pg_rewind failure by file deletion in source server

diff --git a/src/bin/pg_rewind/pg_rewind.c b/src/bin/pg_rewind/pg_rewind.c
index 7e54ac5..ea5385c 100644
--- a/src/bin/pg_rewind/pg_rewind.c
+++ b/src/bin/pg_rewind/pg_rewind.c
@@ -291,6 +291,12 @@ main(int argc, char **argv)
 		print_filemap();
 
 	/*
+	 * Sleep here to allow user to do nasty things with the source file
+	 * list.
+	 */
+	pg_usleep(10000000); /* 10s */
+
+	/*
 	 * Ok, we're ready to start copying things over.
 	 */
 	if (showprogress)

From f12a2cec0489d6c20ed55665bc6698ac701e5d73 Mon Sep 17 00:00:00 2001
From: Michael Paquier <michael@otacoo.com>
Date: Tue, 23 Jun 2015 13:16:23 +0900
Subject: [PATCH 6/6] Make pg_rewind able to detect deleted files on remote
 source

When getting a list of PGDATA files from a remote server with pg_rewind,
it is possible that this list contains temporary files or files that have
been deleted on the remote server after taking the file list, like what
DROP TABLE would do for a relation. This can lead to errors when calling
pg_read_binary_file on an entry that is listed but does not exist anymore,
preventing the rewind from working correctly.

In order to prevent such problems, use the new if_not_exists options
in pg_ls_dir, pg_tablespace_location and pg_read_binary_file to not
fail if a file does not exist anymore and continue process as for
example a relation file removed does not prevent a rewound node from
replaying WAL in recovery, node rewound guaranteed to have a minimum
recovery point set to the current WAL location of the remote node that
is put in sync with.
---
 src/bin/pg_rewind/libpq_fetch.c | 41 ++++++++++++++++++++++++++++++-----------
 1 file changed, 30 insertions(+), 11 deletions(-)

diff --git a/src/bin/pg_rewind/libpq_fetch.c b/src/bin/pg_rewind/libpq_fetch.c
index 6ffd24e..2051d30 100644
--- a/src/bin/pg_rewind/libpq_fetch.c
+++ b/src/bin/pg_rewind/libpq_fetch.c
@@ -149,18 +149,24 @@ libpqProcessFileList(void)
 	sql =
 		"WITH RECURSIVE files (path, filename, size, isdir) AS (\n"
 		"  SELECT '' AS path, filename, size, isdir FROM\n"
-		"  (SELECT pg_ls_dir('.') AS filename) AS fn,\n"
-		"        pg_stat_file(fn.filename) AS this\n"
+		"    (SELECT filename\n"
+		"         FROM pg_ls_dir('.', true, true) AS filename\n"
+		"         WHERE filename NOT IN ('.', '..')) AS fn,\n"
+		"    pg_stat_file(fn.filename, true) AS this\n"
+		"    WHERE this.size IS NOT NULL\n"
 		"  UNION ALL\n"
 		"  SELECT parent.path || parent.filename || '/' AS path,\n"
 		"         fn, this.size, this.isdir\n"
 		"  FROM files AS parent,\n"
-		"       pg_ls_dir(parent.path || parent.filename) AS fn,\n"
-		"       pg_stat_file(parent.path || parent.filename || '/' || fn) AS this\n"
-		"       WHERE parent.isdir = 't'\n"
-		")\n"
-		"SELECT path || filename, size, isdir,\n"
-		"       pg_tablespace_location(pg_tablespace.oid) AS link_target\n"
+		"       pg_ls_dir(parent.path || parent.filename, true, true) AS fn,\n"
+		"       pg_stat_file(parent.path || parent.filename || '/' || fn, true)\n"
+		"              AS this\n"
+		"       WHERE parent.isdir = 't' AND\n"
+		"             (fn NOT IN ('.', '..')) AND\n"
+		"	     this.size IS NOT NULL)\n"
+		"SELECT path || filename AS file_path, size, isdir,\n"
+		"       pg_tablespace_location(pg_tablespace.oid, true)\n"
+		"              AS link_target\n"
 		"FROM files\n"
 		"LEFT OUTER JOIN pg_tablespace ON files.path = 'pg_tblspc/'\n"
 		"                             AND oid::text = files.filename\n";
@@ -259,8 +265,7 @@ receiveFileChunks(const char *sql)
 		}
 
 		if (PQgetisnull(res, 0, 0) ||
-			PQgetisnull(res, 0, 1) ||
-			PQgetisnull(res, 0, 2))
+			PQgetisnull(res, 0, 1))
 		{
 			pg_fatal("unexpected NULL result while fetching remote files\n");
 		}
@@ -278,6 +283,20 @@ receiveFileChunks(const char *sql)
 		memcpy(filename, PQgetvalue(res, 0, 0), filenamelen);
 		filename[filenamelen] = '\0';
 
+		/*
+		 * It may be possible that a file has been deleted on remote side after
+		 * creating the file map. In this case simply ignore it and move on.
+		 */
+		if (PQgetisnull(res, 0, 2))
+		{
+			pg_log(PG_DEBUG,
+				   "received NULL chunk for file \"%s\", file has been deleted\n",
+				   filename);
+			pg_free(filename);
+			PQclear(res);
+			continue;
+		}
+
 		chunk = PQgetvalue(res, 0, 2);
 
 		pg_log(PG_DEBUG, "received chunk for file \"%s\", off %d, len %d\n",
@@ -445,7 +464,7 @@ libpq_executeFileMap(filemap_t *map)
 	 */
 	sql =
 		"SELECT path, begin, \n"
-		"  pg_read_binary_file(path, begin, len) AS chunk\n"
+		"  pg_read_binary_file(path, begin, len, true) AS chunk\n"
 		"FROM fetchchunks\n";
 
 	receiveFileChunks(sql);
-- 
2.4.4

From 454fa9e67c67621b0832d7fbd90153328c99197b Mon Sep 17 00:00:00 2001
From: Michael Paquier <michael@otacoo.com>
Date: Tue, 23 Jun 2015 11:45:49 +0900
Subject: [PATCH 1/6] Extend pg_tablespace_location with if_not_exists option

This is useful for code paths that prefer receive an empty response
instead of an ERROR if tablespace specified does not exist.
---
 doc/src/sgml/func.sgml        |  8 ++++--
 src/backend/utils/adt/misc.c  | 60 ++++++++++++++++++++++++++++++++++---------
 src/include/catalog/pg_proc.h |  2 ++
 src/include/utils/builtins.h  |  1 +
 4 files changed, 57 insertions(+), 14 deletions(-)

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 650051b..7929e7e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -15844,9 +15844,13 @@ SELECT pg_type_is_visible('myschema.widget'::regtype);
        <entry>get the set of database OIDs that have objects in the tablespace</entry>
       </row>
       <row>
-       <entry><literal><function>pg_tablespace_location(<parameter>tablespace_oid</parameter>)</function></literal></entry>
+       <entry><literal><function>pg_tablespace_location(<parameter>tablespace_oid</parameter> [, <parameter>if_not_exists</> <type>boolean</type>])</function></literal></entry>
        <entry><type>text</type></entry>
-       <entry>get the path in the file system that this tablespace is located in</entry>
+       <entry>
+        Get the path in the file system that this tablespace is located in.
+        If <parameter>if_not_exists</parameter> is true, <literal>NULL</literal>
+        is returned if tablespace does not exist instead of an error.
+       </entry>
       </row>
       <row>
        <entry><literal><function>pg_typeof(<parameter>any</parameter>)</function></literal></entry>
diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c
index c0495d9..034728d 100644
--- a/src/backend/utils/adt/misc.c
+++ b/src/backend/utils/adt/misc.c
@@ -336,17 +336,24 @@ pg_tablespace_databases(PG_FUNCTION_ARGS)
 	SRF_RETURN_DONE(funcctx);
 }
 
-
 /*
- * pg_tablespace_location - get location for a tablespace
+ * Wrapper function for pg_tablespace_location and
+ * pg_tablespace_location_extended.
  */
-Datum
-pg_tablespace_location(PG_FUNCTION_ARGS)
+static Datum
+tablespace_location_wrapper(FunctionCallInfo fcinfo)
 {
 	Oid			tablespaceOid = PG_GETARG_OID(0);
 	char		sourcepath[MAXPGPATH];
 	char		targetpath[MAXPGPATH];
 	int			rllen;
+	bool		if_not_exists = false;
+
+	/*
+	 * Check for IF NOT EXISTS option.
+	 */
+	if (PG_NARGS() == 2 && !PG_ARGISNULL(1))
+		if_not_exists = PG_GETARG_BOOL(1);
 
 	/*
 	 * It's useful to apply this function to pg_class.reltablespace, wherein
@@ -373,15 +380,25 @@ pg_tablespace_location(PG_FUNCTION_ARGS)
 
 	rllen = readlink(sourcepath, targetpath, sizeof(targetpath));
 	if (rllen < 0)
-		ereport(ERROR,
-				(errcode_for_file_access(),
-				 errmsg("could not read symbolic link \"%s\": %m",
-						sourcepath)));
+	{
+		if (!if_not_exists)
+			ereport(ERROR,
+					(errcode_for_file_access(),
+					 errmsg("could not read symbolic link \"%s\": %m",
+							sourcepath)));
+		else
+			PG_RETURN_NULL();
+	}
 	if (rllen >= sizeof(targetpath))
-		ereport(ERROR,
-				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
-				 errmsg("symbolic link \"%s\" target is too long",
-						sourcepath)));
+	{
+		if (!if_not_exists)
+			ereport(ERROR,
+					(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+					 errmsg("symbolic link \"%s\" target is too long",
+							sourcepath)));
+		else
+			PG_RETURN_NULL();
+	}
 	targetpath[rllen] = '\0';
 
 	PG_RETURN_TEXT_P(cstring_to_text(targetpath));
@@ -394,6 +411,25 @@ pg_tablespace_location(PG_FUNCTION_ARGS)
 }
 
 /*
+ * pg_tablespace_location - get location for a tablespace
+ */
+Datum
+pg_tablespace_location(PG_FUNCTION_ARGS)
+{
+	return tablespace_location_wrapper(fcinfo);
+}
+
+/*
+ * pg_tablespace_location - get location for a tablespace, with option to
+ * bypass errors in case of a non-existing tablespace.
+ */
+Datum
+pg_tablespace_location_extended(PG_FUNCTION_ARGS)
+{
+	return tablespace_location_wrapper(fcinfo);
+}
+
+/*
  * pg_sleep - delay for N seconds
  */
 Datum
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index 6b3d194..1f163f0 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -2922,6 +2922,8 @@ DESCR("current trigger depth");
 
 DATA(insert OID = 3778 ( pg_tablespace_location PGNSP PGUID 12 1 0 0 0 f f f f t f s 1 0 25 "26" _null_ _null_ _null_ _null_ _null_ pg_tablespace_location _null_ _null_ _null_ ));
 DESCR("tablespace location");
+DATA(insert OID = 3579 ( pg_tablespace_location PGNSP PGUID 12 1 0 0 0 f f f f t f s 2 0 25 "26 16" _null_ _null_ _null_ _null_ _null_ pg_tablespace_location_extended _null_ _null_ _null_ ));
+DESCR("tablespace location");
 
 DATA(insert OID = 1946 (  encode						PGNSP PGUID 12 1 0 0 0 f f f f t f i 2 0 25 "17 25" _null_ _null_ _null_ _null_ _null_ binary_encode _null_ _null_ _null_ ));
 DESCR("convert bytea value into some ascii-only text string");
diff --git a/src/include/utils/builtins.h b/src/include/utils/builtins.h
index 51f25a2..ab78ec2 100644
--- a/src/include/utils/builtins.h
+++ b/src/include/utils/builtins.h
@@ -486,6 +486,7 @@ extern Datum pg_terminate_backend(PG_FUNCTION_ARGS);
 extern Datum pg_reload_conf(PG_FUNCTION_ARGS);
 extern Datum pg_tablespace_databases(PG_FUNCTION_ARGS);
 extern Datum pg_tablespace_location(PG_FUNCTION_ARGS);
+extern Datum pg_tablespace_location_extended(PG_FUNCTION_ARGS);
 extern Datum pg_rotate_logfile(PG_FUNCTION_ARGS);
 extern Datum pg_sleep(PG_FUNCTION_ARGS);
 extern Datum pg_get_keywords(PG_FUNCTION_ARGS);
-- 
2.4.4

From 72ef91958e91e9d6ba4a72d325872edb65166cc7 Mon Sep 17 00:00:00 2001
From: Michael Paquier <michael@otacoo.com>
Date: Tue, 23 Jun 2015 11:48:34 +0900
Subject: [PATCH 2/6] Extend pg_stat_file with if_not_exists option

This is useful for code paths that prefer receiving a NULL result
instead of an ERROR if file specified does not exist.
---
 doc/src/sgml/func.sgml          |  9 ++++--
 src/backend/utils/adt/genfile.c | 65 +++++++++++++++++++++++++++++++----------
 src/include/catalog/pg_proc.h   |  2 ++
 src/include/utils/builtins.h    |  1 +
 4 files changed, 59 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7929e7e..0f70985 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -17830,10 +17830,15 @@ postgres=# SELECT * FROM pg_xlogfile_name_offset(pg_stop_backup());
       </row>
       <row>
        <entry>
-        <literal><function>pg_stat_file(<parameter>filename</> <type>text</>)</function></literal>
+        <literal><function>pg_stat_file(<parameter>filename</> <type>text</>[, <parameter>if_not_exists</> <type>boolean</type>])</function></literal>
        </entry>
        <entry><type>record</type></entry>
-       <entry>Return information about a file</entry>
+       <entry>
+        Return information about a file. If
+        <parameter>if_not_exists</parameter> is true, <literal>NULL</literal>
+        is returned for all result fields if file does not exist instead of
+        an error.
+       </entry>
       </row>
      </tbody>
     </tgroup>
diff --git a/src/backend/utils/adt/genfile.c b/src/backend/utils/adt/genfile.c
index f3f3cca..93eb379 100644
--- a/src/backend/utils/adt/genfile.c
+++ b/src/backend/utils/adt/genfile.c
@@ -254,10 +254,10 @@ pg_read_binary_file_all(PG_FUNCTION_ARGS)
 }
 
 /*
- * stat a file
+ * Wrapper for pg_stat_file and pg_stat_file_extended.
  */
-Datum
-pg_stat_file(PG_FUNCTION_ARGS)
+static Datum
+stat_file_wrapper(PG_FUNCTION_ARGS)
 {
 	text	   *filename_t = PG_GETARG_TEXT_P(0);
 	char	   *filename;
@@ -266,18 +266,29 @@ pg_stat_file(PG_FUNCTION_ARGS)
 	bool		isnull[6];
 	HeapTuple	tuple;
 	TupleDesc	tupdesc;
+	bool		if_not_exists = false;
+	bool		return_null = false;
 
 	if (!superuser())
 		ereport(ERROR,
 				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
 				 (errmsg("must be superuser to get file information"))));
 
+	/* Check for option if_not_exists */
+	if (PG_NARGS() == 2 && !PG_ARGISNULL(1))
+		if_not_exists = PG_GETARG_BOOL(1);
+
 	filename = convert_and_check_filename(filename_t);
 
 	if (stat(filename, &fst) < 0)
-		ereport(ERROR,
-				(errcode_for_file_access(),
-				 errmsg("could not stat file \"%s\": %m", filename)));
+	{
+		if (if_not_exists)
+			return_null = true;
+		else
+			ereport(ERROR,
+					(errcode_for_file_access(),
+					 errmsg("could not stat file \"%s\": %m", filename)));
+	}
 
 	/*
 	 * This record type had better match the output parameters declared for me
@@ -298,20 +309,23 @@ pg_stat_file(PG_FUNCTION_ARGS)
 					   "isdir", BOOLOID, -1, 0);
 	BlessTupleDesc(tupdesc);
 
-	memset(isnull, false, sizeof(isnull));
+	memset(isnull, return_null, sizeof(isnull));
 
-	values[0] = Int64GetDatum((int64) fst.st_size);
-	values[1] = TimestampTzGetDatum(time_t_to_timestamptz(fst.st_atime));
-	values[2] = TimestampTzGetDatum(time_t_to_timestamptz(fst.st_mtime));
-	/* Unix has file status change time, while Win32 has creation time */
+	if (!return_null)
+	{
+		values[0] = Int64GetDatum((int64) fst.st_size);
+		values[1] = TimestampTzGetDatum(time_t_to_timestamptz(fst.st_atime));
+		values[2] = TimestampTzGetDatum(time_t_to_timestamptz(fst.st_mtime));
+		/* Unix has file status change time, while Win32 has creation time */
 #if !defined(WIN32) && !defined(__CYGWIN__)
-	values[3] = TimestampTzGetDatum(time_t_to_timestamptz(fst.st_ctime));
-	isnull[4] = true;
+		values[3] = TimestampTzGetDatum(time_t_to_timestamptz(fst.st_ctime));
+		isnull[4] = true;
 #else
-	isnull[3] = true;
-	values[4] = TimestampTzGetDatum(time_t_to_timestamptz(fst.st_ctime));
+		isnull[3] = true;
+		values[4] = TimestampTzGetDatum(time_t_to_timestamptz(fst.st_ctime));
 #endif
-	values[5] = BoolGetDatum(S_ISDIR(fst.st_mode));
+		values[5] = BoolGetDatum(S_ISDIR(fst.st_mode));
+	}
 
 	tuple = heap_form_tuple(tupdesc, values, isnull);
 
@@ -320,6 +334,25 @@ pg_stat_file(PG_FUNCTION_ARGS)
 	PG_RETURN_DATUM(HeapTupleGetDatum(tuple));
 }
 
+/*
+ * pg_stat_file_extended
+ * Stat a file, with possibility to bypass error in case of a missing file.
+ */
+Datum
+pg_stat_file_extended(PG_FUNCTION_ARGS)
+{
+	return stat_file_wrapper(fcinfo);
+}
+
+/*
+ * stat a file
+ */
+Datum
+pg_stat_file(PG_FUNCTION_ARGS)
+{
+	return stat_file_wrapper(fcinfo);
+}
+
 
 /*
  * List a directory (returns the filenames only)
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index 1f163f0..8da1781 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -3185,6 +3185,8 @@ DESCR("rotate log file");
 
 DATA(insert OID = 2623 ( pg_stat_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v 1 0 2249 "25" "{25,20,1184,1184,1184,1184,16}" "{i,o,o,o,o,o,o}" "{filename,size,access,modification,change,creation,isdir}" _null_ _null_ pg_stat_file _null_ _null_ _null_ ));
 DESCR("get information about file");
+DATA(insert OID = 3307 ( pg_stat_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v 2 0 2249 "25 16" "{25,16,20,1184,1184,1184,1184,16}" "{i,i,o,o,o,o,o,o}" "{filename,if_not_exists,size,access,modification,change,creation,isdir}" _null_ _null_ pg_stat_file_extended _null_ _null_ _null_ ));
+DESCR("get information about file");
 DATA(insert OID = 2624 ( pg_read_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v 3 0 25 "25 20 20" _null_ _null_ _null_ _null_ _null_ pg_read_file _null_ _null_ _null_ ));
 DESCR("read text from a file");
 DATA(insert OID = 3826 ( pg_read_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v 1 0 25 "25" _null_ _null_ _null_ _null_ _null_ pg_read_file_all _null_ _null_ _null_ ));
diff --git a/src/include/utils/builtins.h b/src/include/utils/builtins.h
index ab78ec2..e46650a 100644
--- a/src/include/utils/builtins.h
+++ b/src/include/utils/builtins.h
@@ -472,6 +472,7 @@ extern Datum pg_relation_filepath(PG_FUNCTION_ARGS);
 extern bytea *read_binary_file(const char *filename,
 				 int64 seek_offset, int64 bytes_to_read);
 extern Datum pg_stat_file(PG_FUNCTION_ARGS);
+extern Datum pg_stat_file_extended(PG_FUNCTION_ARGS);
 extern Datum pg_read_file(PG_FUNCTION_ARGS);
 extern Datum pg_read_file_all(PG_FUNCTION_ARGS);
 extern Datum pg_read_binary_file(PG_FUNCTION_ARGS);
-- 
2.4.4

From b4e067ccefef8aac912211aee792af91c624b553 Mon Sep 17 00:00:00 2001
From: Michael Paquier <michael@otacoo.com>
Date: Tue, 23 Jun 2015 11:51:30 +0900
Subject: [PATCH 3/6] Add IF NOT EXISTS to pg_read_file and pg_read_binary_file

This is useful for code paths that do not want to fail if the file
queried does not exist.
---
 doc/src/sgml/func.sgml           |  16 +++-
 src/backend/commands/extension.c |   2 +-
 src/backend/utils/adt/genfile.c  | 174 +++++++++++++++++++++++++++++++++------
 src/include/catalog/pg_proc.h    |   8 ++
 src/include/utils/builtins.h     |   8 +-
 5 files changed, 179 insertions(+), 29 deletions(-)

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 0f70985..edfea8b 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -17816,17 +17816,25 @@ postgres=# SELECT * FROM pg_xlogfile_name_offset(pg_stop_backup());
       </row>
       <row>
        <entry>
-        <literal><function>pg_read_file(<parameter>filename</> <type>text</> [, <parameter>offset</> <type>bigint</>, <parameter>length</> <type>bigint</>])</function></literal>
+        <literal><function>pg_read_file(<parameter>filename</> <type>text</> [, <parameter>offset</> <type>bigint</>, <parameter>length</> <type>bigint</> [, <parameter>if_not_exists</> <type>boolean</>] ])</function></literal>
        </entry>
        <entry><type>text</type></entry>
-       <entry>Return the contents of a text file</entry>
+       <entry>
+        Return the contents of a text file. If
+        <parameter>if_not_exists</parameter> is true, <literal>NULL</literal>
+        is returned if file does not exist instead of an error.
+       </entry>
       </row>
       <row>
        <entry>
-        <literal><function>pg_read_binary_file(<parameter>filename</> <type>text</> [, <parameter>offset</> <type>bigint</>, <parameter>length</> <type>bigint</>])</function></literal>
+        <literal><function>pg_read_binary_file(<parameter>filename</> <type>text</> [, <parameter>offset</> <type>bigint</>, <parameter>length</> <type>bigint</> [, <parameter>if_not_exists</> <type>boolean</>] ])</function></literal>
        </entry>
        <entry><type>bytea</type></entry>
-       <entry>Return the contents of a file</entry>
+       <entry>
+        Return the contents of a file. If
+        <parameter>if_not_exists</parameter> is true, <literal>NULL</literal>
+        is returned if file does not exist instead of an error.
+       </entry>
       </row>
       <row>
        <entry>
diff --git a/src/backend/commands/extension.c b/src/backend/commands/extension.c
index 5cc74d0..25bbe01 100644
--- a/src/backend/commands/extension.c
+++ b/src/backend/commands/extension.c
@@ -640,7 +640,7 @@ read_extension_script_file(const ExtensionControlFile *control,
 	char	   *dest_str;
 	int			len;
 
-	content = read_binary_file(filename, 0, -1);
+	content = read_binary_file(filename, 0, -1, false);
 
 	/* use database encoding if not given */
 	if (control->encoding < 0)
diff --git a/src/backend/utils/adt/genfile.c b/src/backend/utils/adt/genfile.c
index 93eb379..6ce9ec3 100644
--- a/src/backend/utils/adt/genfile.c
+++ b/src/backend/utils/adt/genfile.c
@@ -88,7 +88,8 @@ convert_and_check_filename(text *arg)
  * We read the whole of the file when bytes_to_read is negative.
  */
 bytea *
-read_binary_file(const char *filename, int64 seek_offset, int64 bytes_to_read)
+read_binary_file(const char *filename, int64 seek_offset,
+				 int64 bytes_to_read, bool if_not_exists)
 {
 	bytea	   *buf;
 	size_t		nbytes;
@@ -103,9 +104,14 @@ read_binary_file(const char *filename, int64 seek_offset, int64 bytes_to_read)
 			struct stat fst;
 
 			if (stat(filename, &fst) < 0)
-				ereport(ERROR,
-						(errcode_for_file_access(),
-						 errmsg("could not stat file \"%s\": %m", filename)));
+			{
+				if (if_not_exists)
+					return NULL;
+				else
+					ereport(ERROR,
+							(errcode_for_file_access(),
+							 errmsg("could not stat file \"%s\": %m", filename)));
+			}
 
 			bytes_to_read = fst.st_size - seek_offset;
 		}
@@ -118,10 +124,15 @@ read_binary_file(const char *filename, int64 seek_offset, int64 bytes_to_read)
 				 errmsg("requested length too large")));
 
 	if ((file = AllocateFile(filename, PG_BINARY_R)) == NULL)
-		ereport(ERROR,
-				(errcode_for_file_access(),
-				 errmsg("could not open file \"%s\" for reading: %m",
-						filename)));
+	{
+		if (if_not_exists)
+			return NULL;
+		else
+			ereport(ERROR,
+					(errcode_for_file_access(),
+					 errmsg("could not open file \"%s\" for reading: %m",
+							filename)));
+	}
 
 	if (fseeko(file, (off_t) seek_offset,
 			   (seek_offset >= 0) ? SEEK_SET : SEEK_END) != 0)
@@ -150,11 +161,16 @@ read_binary_file(const char *filename, int64 seek_offset, int64 bytes_to_read)
  * in the database encoding.
  */
 static text *
-read_text_file(const char *filename, int64 seek_offset, int64 bytes_to_read)
+read_text_file(const char *filename, int64 seek_offset,
+			   int64 bytes_to_read, bool if_not_exists)
 {
 	bytea	   *buf;
 
-	buf = read_binary_file(filename, seek_offset, bytes_to_read);
+	buf = read_binary_file(filename, seek_offset,
+						   bytes_to_read, if_not_exists);
+
+	if (buf == NULL)
+		return NULL;
 
 	/* Make sure the input is valid */
 	pg_verifymbstr(VARDATA(buf), VARSIZE(buf) - VARHDRSZ, false);
@@ -164,21 +180,27 @@ read_text_file(const char *filename, int64 seek_offset, int64 bytes_to_read)
 }
 
 /*
- * Read a section of a file, returning it as text
+ * Wrapper function for pg_read_file and pg_read_file_extended.
  */
-Datum
-pg_read_file(PG_FUNCTION_ARGS)
+static Datum
+read_file_wrapper(PG_FUNCTION_ARGS)
 {
 	text	   *filename_t = PG_GETARG_TEXT_P(0);
 	int64		seek_offset = PG_GETARG_INT64(1);
 	int64		bytes_to_read = PG_GETARG_INT64(2);
+	bool		if_not_exists = false;
 	char	   *filename;
+	bytea	   *result;
 
 	if (!superuser())
 		ereport(ERROR,
 				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
 				 (errmsg("must be superuser to read files"))));
 
+	/* Check for option if_not_exists */
+	if (PG_NARGS() == 4 && !PG_ARGISNULL(3))
+		if_not_exists = PG_GETARG_BOOL(3);
+
 	filename = convert_and_check_filename(filename_t);
 
 	if (bytes_to_read < 0)
@@ -186,44 +208,100 @@ pg_read_file(PG_FUNCTION_ARGS)
 				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 				 errmsg("requested length cannot be negative")));
 
-	PG_RETURN_TEXT_P(read_text_file(filename, seek_offset, bytes_to_read));
+	result = read_text_file(filename, seek_offset, bytes_to_read,
+							if_not_exists);
+	if (result == NULL)
+		PG_RETURN_NULL();
+	PG_RETURN_TEXT_P(result);
 }
 
 /*
- * Read the whole of a file, returning it as text
+ * Read a section of a file, returning it as text
  */
 Datum
-pg_read_file_all(PG_FUNCTION_ARGS)
+pg_read_file(PG_FUNCTION_ARGS)
+{
+	return read_file_wrapper(fcinfo);
+}
+
+/*
+ * Similar to pg_read_file, with IF NOT EXISTS option.
+ */
+Datum
+pg_read_file_extended(PG_FUNCTION_ARGS)
+{
+	return read_file_wrapper(fcinfo);
+}
+
+/*
+ * Wrapper function for pg_read_file_all and pg_read_file_all_extended.
+ */
+static Datum
+read_file_all_wrapper(PG_FUNCTION_ARGS)
 {
 	text	   *filename_t = PG_GETARG_TEXT_P(0);
 	char	   *filename;
+	text	   *result;
+	bool		if_not_exists = false;
 
 	if (!superuser())
 		ereport(ERROR,
 				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
 				 (errmsg("must be superuser to read files"))));
 
+	/* Check for option if_not_exists */
+	if (PG_NARGS() == 2 && !PG_ARGISNULL(1))
+		if_not_exists = PG_GETARG_BOOL(1);
+
 	filename = convert_and_check_filename(filename_t);
 
-	PG_RETURN_TEXT_P(read_text_file(filename, 0, -1));
+	result = read_text_file(filename, 0, -1, if_not_exists);
+	if (result == NULL)
+		PG_RETURN_NULL();
+
+	PG_RETURN_TEXT_P(result);
 }
 
 /*
- * Read a section of a file, returning it as bytea
+ * Read the whole of a file, returning it as text
  */
 Datum
-pg_read_binary_file(PG_FUNCTION_ARGS)
+pg_read_file_all(PG_FUNCTION_ARGS)
+{
+	return read_file_all_wrapper(fcinfo);
+}
+
+/*
+ * Similar to pg_read_file_all, with IF NOT EXISTS option.
+ */
+Datum
+pg_read_file_all_extended(PG_FUNCTION_ARGS)
+{
+	return read_file_all_wrapper(fcinfo);
+}
+
+/*
+ * Wrapper for pg_read_binary_file and pg_read_binary_file_extended.
+ */
+static Datum
+read_binary_file_wrapper(PG_FUNCTION_ARGS)
 {
 	text	   *filename_t = PG_GETARG_TEXT_P(0);
 	int64		seek_offset = PG_GETARG_INT64(1);
 	int64		bytes_to_read = PG_GETARG_INT64(2);
 	char	   *filename;
+	bool		if_not_exists = false;
+	bytea	   *result;
 
 	if (!superuser())
 		ereport(ERROR,
 				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
 				 (errmsg("must be superuser to read files"))));
 
+	/* Check for option if_not_exists */
+	if (PG_NARGS() == 4 && !PG_ARGISNULL(3))
+		if_not_exists = PG_GETARG_BOOL(3);
+
 	filename = convert_and_check_filename(filename_t);
 
 	if (bytes_to_read < 0)
@@ -231,26 +309,76 @@ pg_read_binary_file(PG_FUNCTION_ARGS)
 				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 				 errmsg("requested length cannot be negative")));
 
-	PG_RETURN_BYTEA_P(read_binary_file(filename, seek_offset, bytes_to_read));
+	result = read_binary_file(filename, seek_offset,
+							  bytes_to_read, if_not_exists);
+	if (result == NULL)
+		PG_RETURN_NULL();
+	PG_RETURN_BYTEA_P(result);
 }
 
 /*
- * Read the whole of a file, returning it as bytea
+ * Read a section of a file, returning it as bytea
  */
 Datum
-pg_read_binary_file_all(PG_FUNCTION_ARGS)
+pg_read_binary_file(PG_FUNCTION_ARGS)
+{
+	return read_binary_file_wrapper(fcinfo);
+}
+
+/*
+ * Similar to pg_read_binary_file, with IF NOT EXISTS option.
+ */
+Datum
+pg_read_binary_file_extended(PG_FUNCTION_ARGS)
+{
+	return read_binary_file_wrapper(fcinfo);
+}
+
+/*
+ * Wrapper for pg_read_binary_file_all and pg_read_binary_file_all_extended.
+ */
+static Datum
+read_binary_file_all_wrapper(PG_FUNCTION_ARGS)
 {
 	text	   *filename_t = PG_GETARG_TEXT_P(0);
 	char	   *filename;
+	bool		if_not_exists = false;
+	text	   *result;
 
 	if (!superuser())
 		ereport(ERROR,
 				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
 				 (errmsg("must be superuser to read files"))));
 
+	/* Check for option if_not_exists */
+	if (PG_NARGS() == 2 && !PG_ARGISNULL(1))
+		if_not_exists = PG_GETARG_BOOL(1);
+
 	filename = convert_and_check_filename(filename_t);
 
-	PG_RETURN_BYTEA_P(read_binary_file(filename, 0, -1));
+	result = read_binary_file(filename, 0, -1, if_not_exists);
+	if (result == NULL)
+		PG_RETURN_NULL();
+
+	PG_RETURN_BYTEA_P(result);
+}
+
+/*
+ * Read the whole of a file, returning it as bytea
+ */
+Datum
+pg_read_binary_file_all(PG_FUNCTION_ARGS)
+{
+	return read_binary_file_all_wrapper(fcinfo);
+}
+
+/*
+ * Similar to pg_read_binary_file_all, with IF NOT EXISTS option.
+ */
+Datum
+pg_read_binary_file_all_extended(PG_FUNCTION_ARGS)
+{
+	return read_binary_file_all_wrapper(fcinfo);
 }
 
 /*
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index 8da1781..c805a9a 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -3189,12 +3189,20 @@ DATA(insert OID = 3307 ( pg_stat_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v 2 0
 DESCR("get information about file");
 DATA(insert OID = 2624 ( pg_read_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v 3 0 25 "25 20 20" _null_ _null_ _null_ _null_ _null_ pg_read_file _null_ _null_ _null_ ));
 DESCR("read text from a file");
+DATA(insert OID = 3293 ( pg_read_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v 4 0 25 "25 20 20 16" _null_ _null_ _null_ _null_ _null_ pg_read_file_extended _null_ _null_ _null_ ));
+DESCR("read text from a file");
 DATA(insert OID = 3826 ( pg_read_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v 1 0 25 "25" _null_ _null_ _null_ _null_ _null_ pg_read_file_all _null_ _null_ _null_ ));
 DESCR("read text from a file");
+DATA(insert OID = 3294 ( pg_read_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v 2 0 25 "25 16" _null_ _null_ _null_ _null_ _null_ pg_read_file_all_extended _null_ _null_ _null_ ));
+DESCR("read text from a file");
 DATA(insert OID = 3827 ( pg_read_binary_file	PGNSP PGUID 12 1 0 0 0 f f f f t f v 3 0 17 "25 20 20" _null_ _null_ _null_ _null_ _null_ pg_read_binary_file _null_ _null_ _null_ ));
 DESCR("read bytea from a file");
+DATA(insert OID = 3295 ( pg_read_binary_file	PGNSP PGUID 12 1 0 0 0 f f f f t f v 4 0 17 "25 20 20 16" _null_ _null_ _null_ _null_ _null_ pg_read_binary_file_extended _null_ _null_ _null_ ));
+DESCR("read bytea from a file");
 DATA(insert OID = 3828 ( pg_read_binary_file	PGNSP PGUID 12 1 0 0 0 f f f f t f v 1 0 17 "25" _null_ _null_ _null_ _null_ _null_ pg_read_binary_file_all _null_ _null_ _null_ ));
 DESCR("read bytea from a file");
+DATA(insert OID = 3296 ( pg_read_binary_file	PGNSP PGUID 12 1 0 0 0 f f f f t f v 2 0 17 "25 16" _null_ _null_ _null_ _null_ _null_ pg_read_binary_file_all_extended _null_ _null_ _null_ ));
+DESCR("read bytea from a file");
 DATA(insert OID = 2625 ( pg_ls_dir			PGNSP PGUID 12 1 1000 0 0 f f f f t t v 1 0 25 "25" _null_ _null_ _null_ _null_ _null_ pg_ls_dir _null_ _null_ _null_ ));
 DESCR("list all files in a directory");
 DATA(insert OID = 2626 ( pg_sleep			PGNSP PGUID 12 1 0 0 0 f f f f t f v 1 0 2278 "701" _null_ _null_ _null_ _null_ _null_ pg_sleep _null_ _null_ _null_ ));
diff --git a/src/include/utils/builtins.h b/src/include/utils/builtins.h
index e46650a..82d0e18 100644
--- a/src/include/utils/builtins.h
+++ b/src/include/utils/builtins.h
@@ -470,13 +470,19 @@ extern Datum pg_relation_filepath(PG_FUNCTION_ARGS);
 
 /* genfile.c */
 extern bytea *read_binary_file(const char *filename,
-				 int64 seek_offset, int64 bytes_to_read);
+							   int64 seek_offset,
+							   int64 bytes_to_read,
+							   bool if_not_exists);
 extern Datum pg_stat_file(PG_FUNCTION_ARGS);
 extern Datum pg_stat_file_extended(PG_FUNCTION_ARGS);
 extern Datum pg_read_file(PG_FUNCTION_ARGS);
+extern Datum pg_read_file_extended(PG_FUNCTION_ARGS);
 extern Datum pg_read_file_all(PG_FUNCTION_ARGS);
+extern Datum pg_read_file_all_extended(PG_FUNCTION_ARGS);
 extern Datum pg_read_binary_file(PG_FUNCTION_ARGS);
+extern Datum pg_read_binary_file_extended(PG_FUNCTION_ARGS);
 extern Datum pg_read_binary_file_all(PG_FUNCTION_ARGS);
+extern Datum pg_read_binary_file_all_extended(PG_FUNCTION_ARGS);
 extern Datum pg_ls_dir(PG_FUNCTION_ARGS);
 
 /* misc.c */
-- 
2.4.4

From f40a675db5e086a72e52cc9d0394728a0ada95f8 Mon Sep 17 00:00:00 2001
From: Michael Paquier <michael@otacoo.com>
Date: Mon, 22 Jun 2015 21:19:33 +0900
Subject: [PATCH 4/6] Extend pg_ls_dir with include_dot_dirs and if_not_exists

If include_dot_dirs is set to true, "." and ".." are listed in the list
of files listed. If if_not_exists is true, an empty list of files is
returned to caller instead of erroring out if the folder specified does
not exist.
---
 doc/src/sgml/func.sgml          | 10 +++++--
 src/backend/utils/adt/genfile.c | 59 +++++++++++++++++++++++++++++++++--------
 src/include/catalog/pg_proc.h   |  2 ++
 src/include/utils/builtins.h    |  1 +
 4 files changed, 59 insertions(+), 13 deletions(-)

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index edfea8b..e9dc19f 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -17809,10 +17809,16 @@ postgres=# SELECT * FROM pg_xlogfile_name_offset(pg_stop_backup());
      <tbody>
       <row>
        <entry>
-        <literal><function>pg_ls_dir(<parameter>dirname</> <type>text</>)</function></literal>
+        <literal><function>pg_ls_dir(<parameter>dirname</> <type>text</> [, <parameter>if_not_exists</> <type>boolean</>, <parameter>include_dot_dirs</> <type>boolean</>] )</function></literal>
        </entry>
        <entry><type>setof text</type></entry>
-       <entry>List the contents of a directory</entry>
+       <entry>
+        List the contents of a directory.  If
+        <parameter>if_not_exists</parameter> is true, an empty result is
+        returned instead of an error. If <parameter>include_dot_dirs</>
+        is true, <quote>.</> and <quote>..</> are included as well in
+        the returned list.
+       </entry>
       </row>
       <row>
        <entry>
diff --git a/src/backend/utils/adt/genfile.c b/src/backend/utils/adt/genfile.c
index 6ce9ec3..6af7253 100644
--- a/src/backend/utils/adt/genfile.c
+++ b/src/backend/utils/adt/genfile.c
@@ -35,6 +35,7 @@ typedef struct
 {
 	char	   *location;
 	DIR		   *dirdesc;
+	bool		include_dot_dirs;
 } directory_fctx;
 
 
@@ -483,14 +484,15 @@ pg_stat_file(PG_FUNCTION_ARGS)
 
 
 /*
- * List a directory (returns the filenames only)
+ * Wrapper for pg_ls_dir and pg_ls_dir_extended.
  */
-Datum
-pg_ls_dir(PG_FUNCTION_ARGS)
+static Datum
+ls_dir_wrapper(PG_FUNCTION_ARGS)
 {
 	FuncCallContext *funcctx;
 	struct dirent *de;
 	directory_fctx *fctx;
+	MemoryContext	oldcontext;
 
 	if (!superuser())
 		ereport(ERROR,
@@ -499,7 +501,17 @@ pg_ls_dir(PG_FUNCTION_ARGS)
 
 	if (SRF_IS_FIRSTCALL())
 	{
-		MemoryContext oldcontext;
+		bool			if_not_exists = false;
+		bool			include_dot_dirs = false;
+
+		/* see if custom parameters have been passed down */
+		if (PG_NARGS() == 3)
+		{
+			if (!PG_ARGISNULL(1))
+				if_not_exists = PG_GETARG_BOOL(1);
+			if (!PG_ARGISNULL(2))
+				include_dot_dirs = PG_GETARG_BOOL(2);
+		}
 
 		funcctx = SRF_FIRSTCALL_INIT();
 		oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
@@ -508,13 +520,18 @@ pg_ls_dir(PG_FUNCTION_ARGS)
 		fctx->location = convert_and_check_filename(PG_GETARG_TEXT_P(0));
 
 		fctx->dirdesc = AllocateDir(fctx->location);
+		fctx->include_dot_dirs = include_dot_dirs;
 
 		if (!fctx->dirdesc)
-			ereport(ERROR,
-					(errcode_for_file_access(),
-					 errmsg("could not open directory \"%s\": %m",
-							fctx->location)));
-
+		{
+			if (if_not_exists && errno == ENOENT)
+				SRF_RETURN_DONE(funcctx);
+			else
+				ereport(ERROR,
+						(errcode_for_file_access(),
+						 errmsg("could not open directory \"%s\": %m",
+								fctx->location)));
+		}
 		funcctx->user_fctx = fctx;
 		MemoryContextSwitchTo(oldcontext);
 	}
@@ -524,8 +541,9 @@ pg_ls_dir(PG_FUNCTION_ARGS)
 
 	while ((de = ReadDir(fctx->dirdesc, fctx->location)) != NULL)
 	{
-		if (strcmp(de->d_name, ".") == 0 ||
-			strcmp(de->d_name, "..") == 0)
+		if (!fctx->include_dot_dirs &&
+			(strcmp(de->d_name, ".") == 0 ||
+			 strcmp(de->d_name, "..") == 0))
 			continue;
 
 		SRF_RETURN_NEXT(funcctx, CStringGetTextDatum(de->d_name));
@@ -535,3 +553,22 @@ pg_ls_dir(PG_FUNCTION_ARGS)
 
 	SRF_RETURN_DONE(funcctx);
 }
+
+/*
+ * List a directory (returns the filenames only)
+ */
+Datum
+pg_ls_dir(PG_FUNCTION_ARGS)
+{
+	return ls_dir_wrapper(fcinfo);
+}
+
+/*
+ * List a directory (can optionally return dot directories or
+ * use IF NOT EXISTS).
+ */
+Datum
+pg_ls_dir_extended(PG_FUNCTION_ARGS)
+{
+	return ls_dir_wrapper(fcinfo);
+}
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index c805a9a..b559572 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -3205,6 +3205,8 @@ DATA(insert OID = 3296 ( pg_read_binary_file	PGNSP PGUID 12 1 0 0 0 f f f f t f
 DESCR("read bytea from a file");
 DATA(insert OID = 2625 ( pg_ls_dir			PGNSP PGUID 12 1 1000 0 0 f f f f t t v 1 0 25 "25" _null_ _null_ _null_ _null_ _null_ pg_ls_dir _null_ _null_ _null_ ));
 DESCR("list all files in a directory");
+DATA(insert OID = 3297 ( pg_ls_dir			PGNSP PGUID 12 1 1000 0 0 f f f f t t v 3 0 25 "25 16 16" _null_ _null_ _null_ _null_ _null_ pg_ls_dir_extended _null_ _null_ _null_ ));
+DESCR("list all files in a directory");
 DATA(insert OID = 2626 ( pg_sleep			PGNSP PGUID 12 1 0 0 0 f f f f t f v 1 0 2278 "701" _null_ _null_ _null_ _null_ _null_ pg_sleep _null_ _null_ _null_ ));
 DESCR("sleep for the specified time in seconds");
 DATA(insert OID = 3935 ( pg_sleep_for			PGNSP PGUID 14 1 0 0 0 f f f f t f v 1 0 2278 "1186" _null_ _null_ _null_ _null_ _null_ "select pg_catalog.pg_sleep(extract(epoch from pg_catalog.clock_timestamp() operator(pg_catalog.+) $1) operator(pg_catalog.-) extract(epoch from pg_catalog.clock_timestamp()))" _null_ _null_ _null_ ));
diff --git a/src/include/utils/builtins.h b/src/include/utils/builtins.h
index 82d0e18..446cda6 100644
--- a/src/include/utils/builtins.h
+++ b/src/include/utils/builtins.h
@@ -484,6 +484,7 @@ extern Datum pg_read_binary_file_extended(PG_FUNCTION_ARGS);
 extern Datum pg_read_binary_file_all(PG_FUNCTION_ARGS);
 extern Datum pg_read_binary_file_all_extended(PG_FUNCTION_ARGS);
 extern Datum pg_ls_dir(PG_FUNCTION_ARGS);
+extern Datum pg_ls_dir_extended(PG_FUNCTION_ARGS);
 
 /* misc.c */
 extern Datum current_database(PG_FUNCTION_ARGS);
-- 
2.4.4

From b15d22e38f0a27e0fedf3fb07e26dcb580f42cb9 Mon Sep 17 00:00:00 2001
From: Michael Paquier <michael@otacoo.com>
Date: Tue, 23 Jun 2015 10:42:48 +0900
Subject: [PATCH 5/6] Add regression tests for pg_ls_dir and
 pg_read_[binary_]file

With the new options if_not_exists that have been added, this looks
worth adding.
---
 src/test/regress/expected/file.out | 84 ++++++++++++++++++++++++++++++++++++++
 src/test/regress/parallel_schedule |  3 ++
 src/test/regress/sql/file.sql      | 29 +++++++++++++
 3 files changed, 116 insertions(+)
 create mode 100644 src/test/regress/expected/file.out
 create mode 100644 src/test/regress/sql/file.sql

diff --git a/src/test/regress/expected/file.out b/src/test/regress/expected/file.out
new file mode 100644
index 0000000..0ddae30
--- /dev/null
+++ b/src/test/regress/expected/file.out
@@ -0,0 +1,84 @@
+--
+-- FILE
+--
+-- Tests of SQL functions interacting directly with files of PGDATA
+-- pg_read_file
+SELECT pg_read_file('postgresql.auto.conf', 0, 23); -- OK
+      pg_read_file       
+-------------------------
+ # Do not edit this file
+(1 row)
+
+SELECT pg_read_file('postgresql_not_exists', 0, 23); -- not OK
+ERROR:  could not open file "postgresql_not_exists" for reading: No such file or directory
+SELECT pg_read_file('postgresql_not_exists', 0, 23, false); -- not OK
+ERROR:  could not open file "postgresql_not_exists" for reading: No such file or directory
+SELECT pg_read_file('postgresql_not_exists', 0, 23, true); -- OK
+ pg_read_file 
+--------------
+ 
+(1 row)
+
+-- pg_read_binary_file
+SELECT pg_read_binary_file('postgresql.auto.conf', 0, 23); -- OK
+               pg_read_binary_file                
+--------------------------------------------------
+ \x2320446f206e6f74206564697420746869732066696c65
+(1 row)
+
+SELECT pg_read_binary_file('postgresql_not_exists', 0, 23); -- not OK
+ERROR:  could not open file "postgresql_not_exists" for reading: No such file or directory
+SELECT pg_read_binary_file('postgresql_not_exists', 0, 23, false); -- not OK
+ERROR:  could not open file "postgresql_not_exists" for reading: No such file or directory
+SELECT pg_read_binary_file('postgresql_not_exists', 0, 23, true); -- OK
+ pg_read_binary_file 
+---------------------
+ 
+(1 row)
+
+-- pg_ls_dir
+SELECT pg_ls_dir('postgresql.conf'); -- not OK, not a directory
+ERROR:  could not open directory "postgresql.conf": Not a directory
+SELECT pg_ls_dir('pg_twophase'); -- empty directory
+ pg_ls_dir 
+-----------
+(0 rows)
+
+SELECT pg_ls_dir('pg_twophase', true, true); -- OK, not empty list
+ pg_ls_dir 
+-----------
+ .
+ ..
+(2 rows)
+
+SELECT pg_ls_dir('pg_twophase', false, false); -- OK, empty list
+ pg_ls_dir 
+-----------
+(0 rows)
+
+SELECT pg_ls_dir('pg_twophase', false, true); -- OK, not empty list
+ pg_ls_dir 
+-----------
+ .
+ ..
+(2 rows)
+
+SELECT pg_ls_dir('pg_twophase', true, false); -- OK, empty list
+ pg_ls_dir 
+-----------
+(0 rows)
+
+SELECT pg_ls_dir('postgresql_not_exists', false, true); -- not OK
+ERROR:  could not open directory "postgresql_not_exists": No such file or directory
+SELECT pg_ls_dir('postgresql_not_exists', false, false); -- not OK
+ERROR:  could not open directory "postgresql_not_exists": No such file or directory
+SELECT pg_ls_dir('postgresql_not_exists', true, true); -- OK, empty list
+ pg_ls_dir 
+-----------
+(0 rows)
+
+SELECT pg_ls_dir('postgresql_not_exists', true, false); -- OK, empty list
+ pg_ls_dir 
+-----------
+(0 rows)
+
diff --git a/src/test/regress/parallel_schedule b/src/test/regress/parallel_schedule
index 91780cd..b1739fa 100644
--- a/src/test/regress/parallel_schedule
+++ b/src/test/regress/parallel_schedule
@@ -108,5 +108,8 @@ test: plancache limit plpgsql copy2 temp domain rangefuncs prepare without_oid c
 # event triggers cannot run concurrently with any test that runs DDL
 test: event_trigger
 
+# Files read during this test may be modified in parallel by other tests
+test: file
+
 # run stats by itself because its delay may be insufficient under heavy load
 test: stats
diff --git a/src/test/regress/sql/file.sql b/src/test/regress/sql/file.sql
new file mode 100644
index 0000000..a0238f2
--- /dev/null
+++ b/src/test/regress/sql/file.sql
@@ -0,0 +1,29 @@
+--
+-- FILE
+--
+
+-- Tests of SQL functions interacting directly with files of PGDATA
+
+-- pg_read_file
+SELECT pg_read_file('postgresql.auto.conf', 0, 23); -- OK
+SELECT pg_read_file('postgresql_not_exists', 0, 23); -- not OK
+SELECT pg_read_file('postgresql_not_exists', 0, 23, false); -- not OK
+SELECT pg_read_file('postgresql_not_exists', 0, 23, true); -- OK
+
+-- pg_read_binary_file
+SELECT pg_read_binary_file('postgresql.auto.conf', 0, 23); -- OK
+SELECT pg_read_binary_file('postgresql_not_exists', 0, 23); -- not OK
+SELECT pg_read_binary_file('postgresql_not_exists', 0, 23, false); -- not OK
+SELECT pg_read_binary_file('postgresql_not_exists', 0, 23, true); -- OK
+
+-- pg_ls_dir
+SELECT pg_ls_dir('postgresql.conf'); -- not OK, not a directory
+SELECT pg_ls_dir('pg_twophase'); -- empty directory
+SELECT pg_ls_dir('pg_twophase', true, true); -- OK, not empty list
+SELECT pg_ls_dir('pg_twophase', false, false); -- OK, empty list
+SELECT pg_ls_dir('pg_twophase', false, true); -- OK, not empty list
+SELECT pg_ls_dir('pg_twophase', true, false); -- OK, empty list
+SELECT pg_ls_dir('postgresql_not_exists', false, true); -- not OK
+SELECT pg_ls_dir('postgresql_not_exists', false, false); -- not OK
+SELECT pg_ls_dir('postgresql_not_exists', true, true); -- OK, empty list
+SELECT pg_ls_dir('postgresql_not_exists', true, false); -- OK, empty list
-- 
2.4.4

diff --git a/src/bin/pg_rewind/pg_rewind.c b/src/bin/pg_rewind/pg_rewind.c
index 7e54ac5..ea5385c 100644
--- a/src/bin/pg_rewind/pg_rewind.c
+++ b/src/bin/pg_rewind/pg_rewind.c
@@ -291,6 +291,12 @@ main(int argc, char **argv)
 		print_filemap();
 
 	/*
+	 * Sleep here to allow user to do nasty things with the source file
+	 * list.
+	 */
+	pg_usleep(10000000); /* 10s */
+
+	/*
 	 * Ok, we're ready to start copying things over.
 	 */
 	if (showprogress)

From 228d17d6808d350507a2ef137c7bdb496dc765d3 Mon Sep 17 00:00:00 2001
From: Michael Paquier <michael@otacoo.com>
Date: Wed, 24 Jun 2015 10:32:01 +0900
Subject: [PATCH 1/8] Extend pg_tablespace_location with if_not_exists option

This is useful for code paths that prefer receive an empty response
instead of an ERROR if tablespace specified does not exist.
---
 doc/src/sgml/func.sgml        |  8 +++++--
 src/backend/utils/adt/misc.c  | 49 ++++++++++++++++++++++++++++++++++++-------
 src/include/catalog/pg_proc.h |  2 ++
 src/include/utils/builtins.h  |  1 +
 4 files changed, 50 insertions(+), 10 deletions(-)

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 650051b..7929e7e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -15844,9 +15844,13 @@ SELECT pg_type_is_visible('myschema.widget'::regtype);
        <entry>get the set of database OIDs that have objects in the tablespace</entry>
       </row>
       <row>
-       <entry><literal><function>pg_tablespace_location(<parameter>tablespace_oid</parameter>)</function></literal></entry>
+       <entry><literal><function>pg_tablespace_location(<parameter>tablespace_oid</parameter> [, <parameter>if_not_exists</> <type>boolean</type>])</function></literal></entry>
        <entry><type>text</type></entry>
-       <entry>get the path in the file system that this tablespace is located in</entry>
+       <entry>
+        Get the path in the file system that this tablespace is located in.
+        If <parameter>if_not_exists</parameter> is true, <literal>NULL</literal>
+        is returned if tablespace does not exist instead of an error.
+       </entry>
       </row>
       <row>
        <entry><literal><function>pg_typeof(<parameter>any</parameter>)</function></literal></entry>
diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c
index c0495d9..dc19c2c 100644
--- a/src/backend/utils/adt/misc.c
+++ b/src/backend/utils/adt/misc.c
@@ -336,17 +336,24 @@ pg_tablespace_databases(PG_FUNCTION_ARGS)
 	SRF_RETURN_DONE(funcctx);
 }
 
-
 /*
- * pg_tablespace_location - get location for a tablespace
+ * Wrapper function for pg_tablespace_location and
+ * pg_tablespace_location_extended.
  */
-Datum
-pg_tablespace_location(PG_FUNCTION_ARGS)
+static Datum
+tablespace_location_wrapper(FunctionCallInfo fcinfo)
 {
 	Oid			tablespaceOid = PG_GETARG_OID(0);
 	char		sourcepath[MAXPGPATH];
 	char		targetpath[MAXPGPATH];
 	int			rllen;
+	bool		if_not_exists = false;
+
+	/*
+	 * Check for IF NOT EXISTS option.
+	 */
+	if (PG_NARGS() == 2 && !PG_ARGISNULL(1))
+		if_not_exists = PG_GETARG_BOOL(1);
 
 	/*
 	 * It's useful to apply this function to pg_class.reltablespace, wherein
@@ -373,15 +380,22 @@ pg_tablespace_location(PG_FUNCTION_ARGS)
 
 	rllen = readlink(sourcepath, targetpath, sizeof(targetpath));
 	if (rllen < 0)
-		ereport(ERROR,
-				(errcode_for_file_access(),
-				 errmsg("could not read symbolic link \"%s\": %m",
-						sourcepath)));
+	{
+		if (if_not_exists && errno == ENOENT)
+			PG_RETURN_NULL();
+		else
+			ereport(ERROR,
+					(errcode_for_file_access(),
+					 errmsg("could not read symbolic link \"%s\": %m",
+							sourcepath)));
+	}
 	if (rllen >= sizeof(targetpath))
+	{
 		ereport(ERROR,
 				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
 				 errmsg("symbolic link \"%s\" target is too long",
 						sourcepath)));
+	}
 	targetpath[rllen] = '\0';
 
 	PG_RETURN_TEXT_P(cstring_to_text(targetpath));
@@ -394,6 +408,25 @@ pg_tablespace_location(PG_FUNCTION_ARGS)
 }
 
 /*
+ * pg_tablespace_location - get location for a tablespace
+ */
+Datum
+pg_tablespace_location(PG_FUNCTION_ARGS)
+{
+	return tablespace_location_wrapper(fcinfo);
+}
+
+/*
+ * pg_tablespace_location - get location for a tablespace, with option to
+ * bypass errors in case of a non-existing tablespace.
+ */
+Datum
+pg_tablespace_location_extended(PG_FUNCTION_ARGS)
+{
+	return tablespace_location_wrapper(fcinfo);
+}
+
+/*
  * pg_sleep - delay for N seconds
  */
 Datum
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index 6b3d194..1f163f0 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -2922,6 +2922,8 @@ DESCR("current trigger depth");
 
 DATA(insert OID = 3778 ( pg_tablespace_location PGNSP PGUID 12 1 0 0 0 f f f f t f s 1 0 25 "26" _null_ _null_ _null_ _null_ _null_ pg_tablespace_location _null_ _null_ _null_ ));
 DESCR("tablespace location");
+DATA(insert OID = 3579 ( pg_tablespace_location PGNSP PGUID 12 1 0 0 0 f f f f t f s 2 0 25 "26 16" _null_ _null_ _null_ _null_ _null_ pg_tablespace_location_extended _null_ _null_ _null_ ));
+DESCR("tablespace location");
 
 DATA(insert OID = 1946 (  encode						PGNSP PGUID 12 1 0 0 0 f f f f t f i 2 0 25 "17 25" _null_ _null_ _null_ _null_ _null_ binary_encode _null_ _null_ _null_ ));
 DESCR("convert bytea value into some ascii-only text string");
diff --git a/src/include/utils/builtins.h b/src/include/utils/builtins.h
index 51f25a2..ab78ec2 100644
--- a/src/include/utils/builtins.h
+++ b/src/include/utils/builtins.h
@@ -486,6 +486,7 @@ extern Datum pg_terminate_backend(PG_FUNCTION_ARGS);
 extern Datum pg_reload_conf(PG_FUNCTION_ARGS);
 extern Datum pg_tablespace_databases(PG_FUNCTION_ARGS);
 extern Datum pg_tablespace_location(PG_FUNCTION_ARGS);
+extern Datum pg_tablespace_location_extended(PG_FUNCTION_ARGS);
 extern Datum pg_rotate_logfile(PG_FUNCTION_ARGS);
 extern Datum pg_sleep(PG_FUNCTION_ARGS);
 extern Datum pg_get_keywords(PG_FUNCTION_ARGS);
-- 
2.4.4

From 2804fdc5fd974e688a930ab58559dbb7047cca8e Mon Sep 17 00:00:00 2001
From: Michael Paquier <michael@otacoo.com>
Date: Wed, 24 Jun 2015 10:34:17 +0900
Subject: [PATCH 2/8] Extend pg_stat_file with if_not_exists option

This is useful for code paths that prefer receiving a NULL result
instead of an ERROR if file specified does not exist.
---
 doc/src/sgml/func.sgml          |  9 ++++--
 src/backend/utils/adt/genfile.c | 65 +++++++++++++++++++++++++++++++----------
 src/include/catalog/pg_proc.h   |  2 ++
 src/include/utils/builtins.h    |  1 +
 4 files changed, 59 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7929e7e..0f70985 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -17830,10 +17830,15 @@ postgres=# SELECT * FROM pg_xlogfile_name_offset(pg_stop_backup());
       </row>
       <row>
        <entry>
-        <literal><function>pg_stat_file(<parameter>filename</> <type>text</>)</function></literal>
+        <literal><function>pg_stat_file(<parameter>filename</> <type>text</>[, <parameter>if_not_exists</> <type>boolean</type>])</function></literal>
        </entry>
        <entry><type>record</type></entry>
-       <entry>Return information about a file</entry>
+       <entry>
+        Return information about a file. If
+        <parameter>if_not_exists</parameter> is true, <literal>NULL</literal>
+        is returned for all result fields if file does not exist instead of
+        an error.
+       </entry>
       </row>
      </tbody>
     </tgroup>
diff --git a/src/backend/utils/adt/genfile.c b/src/backend/utils/adt/genfile.c
index f3f3cca..dd97d83 100644
--- a/src/backend/utils/adt/genfile.c
+++ b/src/backend/utils/adt/genfile.c
@@ -254,10 +254,10 @@ pg_read_binary_file_all(PG_FUNCTION_ARGS)
 }
 
 /*
- * stat a file
+ * Wrapper for pg_stat_file and pg_stat_file_extended.
  */
-Datum
-pg_stat_file(PG_FUNCTION_ARGS)
+static Datum
+stat_file_wrapper(PG_FUNCTION_ARGS)
 {
 	text	   *filename_t = PG_GETARG_TEXT_P(0);
 	char	   *filename;
@@ -266,18 +266,29 @@ pg_stat_file(PG_FUNCTION_ARGS)
 	bool		isnull[6];
 	HeapTuple	tuple;
 	TupleDesc	tupdesc;
+	bool		if_not_exists = false;
+	bool		return_null = false;
 
 	if (!superuser())
 		ereport(ERROR,
 				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
 				 (errmsg("must be superuser to get file information"))));
 
+	/* Check for option if_not_exists */
+	if (PG_NARGS() == 2 && !PG_ARGISNULL(1))
+		if_not_exists = PG_GETARG_BOOL(1);
+
 	filename = convert_and_check_filename(filename_t);
 
 	if (stat(filename, &fst) < 0)
-		ereport(ERROR,
-				(errcode_for_file_access(),
-				 errmsg("could not stat file \"%s\": %m", filename)));
+	{
+		if (if_not_exists && errno == ENOENT)
+			return_null = true;
+		else
+			ereport(ERROR,
+					(errcode_for_file_access(),
+					 errmsg("could not stat file \"%s\": %m", filename)));
+	}
 
 	/*
 	 * This record type had better match the output parameters declared for me
@@ -298,20 +309,23 @@ pg_stat_file(PG_FUNCTION_ARGS)
 					   "isdir", BOOLOID, -1, 0);
 	BlessTupleDesc(tupdesc);
 
-	memset(isnull, false, sizeof(isnull));
+	memset(isnull, return_null, sizeof(isnull));
 
-	values[0] = Int64GetDatum((int64) fst.st_size);
-	values[1] = TimestampTzGetDatum(time_t_to_timestamptz(fst.st_atime));
-	values[2] = TimestampTzGetDatum(time_t_to_timestamptz(fst.st_mtime));
-	/* Unix has file status change time, while Win32 has creation time */
+	if (!return_null)
+	{
+		values[0] = Int64GetDatum((int64) fst.st_size);
+		values[1] = TimestampTzGetDatum(time_t_to_timestamptz(fst.st_atime));
+		values[2] = TimestampTzGetDatum(time_t_to_timestamptz(fst.st_mtime));
+		/* Unix has file status change time, while Win32 has creation time */
 #if !defined(WIN32) && !defined(__CYGWIN__)
-	values[3] = TimestampTzGetDatum(time_t_to_timestamptz(fst.st_ctime));
-	isnull[4] = true;
+		values[3] = TimestampTzGetDatum(time_t_to_timestamptz(fst.st_ctime));
+		isnull[4] = true;
 #else
-	isnull[3] = true;
-	values[4] = TimestampTzGetDatum(time_t_to_timestamptz(fst.st_ctime));
+		isnull[3] = true;
+		values[4] = TimestampTzGetDatum(time_t_to_timestamptz(fst.st_ctime));
 #endif
-	values[5] = BoolGetDatum(S_ISDIR(fst.st_mode));
+		values[5] = BoolGetDatum(S_ISDIR(fst.st_mode));
+	}
 
 	tuple = heap_form_tuple(tupdesc, values, isnull);
 
@@ -320,6 +334,25 @@ pg_stat_file(PG_FUNCTION_ARGS)
 	PG_RETURN_DATUM(HeapTupleGetDatum(tuple));
 }
 
+/*
+ * pg_stat_file_extended
+ * Stat a file, with possibility to bypass error in case of a missing file.
+ */
+Datum
+pg_stat_file_extended(PG_FUNCTION_ARGS)
+{
+	return stat_file_wrapper(fcinfo);
+}
+
+/*
+ * stat a file
+ */
+Datum
+pg_stat_file(PG_FUNCTION_ARGS)
+{
+	return stat_file_wrapper(fcinfo);
+}
+
 
 /*
  * List a directory (returns the filenames only)
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index 1f163f0..8da1781 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -3185,6 +3185,8 @@ DESCR("rotate log file");
 
 DATA(insert OID = 2623 ( pg_stat_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v 1 0 2249 "25" "{25,20,1184,1184,1184,1184,16}" "{i,o,o,o,o,o,o}" "{filename,size,access,modification,change,creation,isdir}" _null_ _null_ pg_stat_file _null_ _null_ _null_ ));
 DESCR("get information about file");
+DATA(insert OID = 3307 ( pg_stat_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v 2 0 2249 "25 16" "{25,16,20,1184,1184,1184,1184,16}" "{i,i,o,o,o,o,o,o}" "{filename,if_not_exists,size,access,modification,change,creation,isdir}" _null_ _null_ pg_stat_file_extended _null_ _null_ _null_ ));
+DESCR("get information about file");
 DATA(insert OID = 2624 ( pg_read_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v 3 0 25 "25 20 20" _null_ _null_ _null_ _null_ _null_ pg_read_file _null_ _null_ _null_ ));
 DESCR("read text from a file");
 DATA(insert OID = 3826 ( pg_read_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v 1 0 25 "25" _null_ _null_ _null_ _null_ _null_ pg_read_file_all _null_ _null_ _null_ ));
diff --git a/src/include/utils/builtins.h b/src/include/utils/builtins.h
index ab78ec2..e46650a 100644
--- a/src/include/utils/builtins.h
+++ b/src/include/utils/builtins.h
@@ -472,6 +472,7 @@ extern Datum pg_relation_filepath(PG_FUNCTION_ARGS);
 extern bytea *read_binary_file(const char *filename,
 				 int64 seek_offset, int64 bytes_to_read);
 extern Datum pg_stat_file(PG_FUNCTION_ARGS);
+extern Datum pg_stat_file_extended(PG_FUNCTION_ARGS);
 extern Datum pg_read_file(PG_FUNCTION_ARGS);
 extern Datum pg_read_file_all(PG_FUNCTION_ARGS);
 extern Datum pg_read_binary_file(PG_FUNCTION_ARGS);
-- 
2.4.4

From 0b6b6b438d6a17573f929e50c3adfd726f0b3948 Mon Sep 17 00:00:00 2001
From: Michael Paquier <michael@otacoo.com>
Date: Wed, 24 Jun 2015 10:37:31 +0900
Subject: [PATCH 3/8] Add IF NOT EXISTS to pg_read_file and pg_read_binary_file

This is useful for code paths that do not want to fail if the file
queried does not exist.
---
 doc/src/sgml/func.sgml           |  16 +++-
 src/backend/commands/extension.c |   2 +-
 src/backend/utils/adt/genfile.c  | 174 +++++++++++++++++++++++++++++++++------
 src/include/catalog/pg_proc.h    |   8 ++
 src/include/utils/builtins.h     |   8 +-
 5 files changed, 179 insertions(+), 29 deletions(-)

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 0f70985..edfea8b 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -17816,17 +17816,25 @@ postgres=# SELECT * FROM pg_xlogfile_name_offset(pg_stop_backup());
       </row>
       <row>
        <entry>
-        <literal><function>pg_read_file(<parameter>filename</> <type>text</> [, <parameter>offset</> <type>bigint</>, <parameter>length</> <type>bigint</>])</function></literal>
+        <literal><function>pg_read_file(<parameter>filename</> <type>text</> [, <parameter>offset</> <type>bigint</>, <parameter>length</> <type>bigint</> [, <parameter>if_not_exists</> <type>boolean</>] ])</function></literal>
        </entry>
        <entry><type>text</type></entry>
-       <entry>Return the contents of a text file</entry>
+       <entry>
+        Return the contents of a text file. If
+        <parameter>if_not_exists</parameter> is true, <literal>NULL</literal>
+        is returned if file does not exist instead of an error.
+       </entry>
       </row>
       <row>
        <entry>
-        <literal><function>pg_read_binary_file(<parameter>filename</> <type>text</> [, <parameter>offset</> <type>bigint</>, <parameter>length</> <type>bigint</>])</function></literal>
+        <literal><function>pg_read_binary_file(<parameter>filename</> <type>text</> [, <parameter>offset</> <type>bigint</>, <parameter>length</> <type>bigint</> [, <parameter>if_not_exists</> <type>boolean</>] ])</function></literal>
        </entry>
        <entry><type>bytea</type></entry>
-       <entry>Return the contents of a file</entry>
+       <entry>
+        Return the contents of a file. If
+        <parameter>if_not_exists</parameter> is true, <literal>NULL</literal>
+        is returned if file does not exist instead of an error.
+       </entry>
       </row>
       <row>
        <entry>
diff --git a/src/backend/commands/extension.c b/src/backend/commands/extension.c
index 5cc74d0..25bbe01 100644
--- a/src/backend/commands/extension.c
+++ b/src/backend/commands/extension.c
@@ -640,7 +640,7 @@ read_extension_script_file(const ExtensionControlFile *control,
 	char	   *dest_str;
 	int			len;
 
-	content = read_binary_file(filename, 0, -1);
+	content = read_binary_file(filename, 0, -1, false);
 
 	/* use database encoding if not given */
 	if (control->encoding < 0)
diff --git a/src/backend/utils/adt/genfile.c b/src/backend/utils/adt/genfile.c
index dd97d83..d45c66e 100644
--- a/src/backend/utils/adt/genfile.c
+++ b/src/backend/utils/adt/genfile.c
@@ -88,7 +88,8 @@ convert_and_check_filename(text *arg)
  * We read the whole of the file when bytes_to_read is negative.
  */
 bytea *
-read_binary_file(const char *filename, int64 seek_offset, int64 bytes_to_read)
+read_binary_file(const char *filename, int64 seek_offset,
+				 int64 bytes_to_read, bool if_not_exists)
 {
 	bytea	   *buf;
 	size_t		nbytes;
@@ -103,9 +104,14 @@ read_binary_file(const char *filename, int64 seek_offset, int64 bytes_to_read)
 			struct stat fst;
 
 			if (stat(filename, &fst) < 0)
-				ereport(ERROR,
-						(errcode_for_file_access(),
-						 errmsg("could not stat file \"%s\": %m", filename)));
+			{
+				if (if_not_exists && errno == ENOENT)
+					return NULL;
+				else
+					ereport(ERROR,
+							(errcode_for_file_access(),
+							 errmsg("could not stat file \"%s\": %m", filename)));
+			}
 
 			bytes_to_read = fst.st_size - seek_offset;
 		}
@@ -118,10 +124,15 @@ read_binary_file(const char *filename, int64 seek_offset, int64 bytes_to_read)
 				 errmsg("requested length too large")));
 
 	if ((file = AllocateFile(filename, PG_BINARY_R)) == NULL)
-		ereport(ERROR,
-				(errcode_for_file_access(),
-				 errmsg("could not open file \"%s\" for reading: %m",
-						filename)));
+	{
+		if (if_not_exists && errno == ENOENT)
+			return NULL;
+		else
+			ereport(ERROR,
+					(errcode_for_file_access(),
+					 errmsg("could not open file \"%s\" for reading: %m",
+							filename)));
+	}
 
 	if (fseeko(file, (off_t) seek_offset,
 			   (seek_offset >= 0) ? SEEK_SET : SEEK_END) != 0)
@@ -150,11 +161,16 @@ read_binary_file(const char *filename, int64 seek_offset, int64 bytes_to_read)
  * in the database encoding.
  */
 static text *
-read_text_file(const char *filename, int64 seek_offset, int64 bytes_to_read)
+read_text_file(const char *filename, int64 seek_offset,
+			   int64 bytes_to_read, bool if_not_exists)
 {
 	bytea	   *buf;
 
-	buf = read_binary_file(filename, seek_offset, bytes_to_read);
+	buf = read_binary_file(filename, seek_offset,
+						   bytes_to_read, if_not_exists);
+
+	if (buf == NULL)
+		return NULL;
 
 	/* Make sure the input is valid */
 	pg_verifymbstr(VARDATA(buf), VARSIZE(buf) - VARHDRSZ, false);
@@ -164,21 +180,27 @@ read_text_file(const char *filename, int64 seek_offset, int64 bytes_to_read)
 }
 
 /*
- * Read a section of a file, returning it as text
+ * Wrapper function for pg_read_file and pg_read_file_extended.
  */
-Datum
-pg_read_file(PG_FUNCTION_ARGS)
+static Datum
+read_file_wrapper(PG_FUNCTION_ARGS)
 {
 	text	   *filename_t = PG_GETARG_TEXT_P(0);
 	int64		seek_offset = PG_GETARG_INT64(1);
 	int64		bytes_to_read = PG_GETARG_INT64(2);
+	bool		if_not_exists = false;
 	char	   *filename;
+	bytea	   *result;
 
 	if (!superuser())
 		ereport(ERROR,
 				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
 				 (errmsg("must be superuser to read files"))));
 
+	/* Check for option if_not_exists */
+	if (PG_NARGS() == 4 && !PG_ARGISNULL(3))
+		if_not_exists = PG_GETARG_BOOL(3);
+
 	filename = convert_and_check_filename(filename_t);
 
 	if (bytes_to_read < 0)
@@ -186,44 +208,100 @@ pg_read_file(PG_FUNCTION_ARGS)
 				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 				 errmsg("requested length cannot be negative")));
 
-	PG_RETURN_TEXT_P(read_text_file(filename, seek_offset, bytes_to_read));
+	result = read_text_file(filename, seek_offset, bytes_to_read,
+							if_not_exists);
+	if (result == NULL)
+		PG_RETURN_NULL();
+	PG_RETURN_TEXT_P(result);
 }
 
 /*
- * Read the whole of a file, returning it as text
+ * Read a section of a file, returning it as text
  */
 Datum
-pg_read_file_all(PG_FUNCTION_ARGS)
+pg_read_file(PG_FUNCTION_ARGS)
+{
+	return read_file_wrapper(fcinfo);
+}
+
+/*
+ * Similar to pg_read_file, with IF NOT EXISTS option.
+ */
+Datum
+pg_read_file_extended(PG_FUNCTION_ARGS)
+{
+	return read_file_wrapper(fcinfo);
+}
+
+/*
+ * Wrapper function for pg_read_file_all and pg_read_file_all_extended.
+ */
+static Datum
+read_file_all_wrapper(PG_FUNCTION_ARGS)
 {
 	text	   *filename_t = PG_GETARG_TEXT_P(0);
 	char	   *filename;
+	text	   *result;
+	bool		if_not_exists = false;
 
 	if (!superuser())
 		ereport(ERROR,
 				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
 				 (errmsg("must be superuser to read files"))));
 
+	/* Check for option if_not_exists */
+	if (PG_NARGS() == 2 && !PG_ARGISNULL(1))
+		if_not_exists = PG_GETARG_BOOL(1);
+
 	filename = convert_and_check_filename(filename_t);
 
-	PG_RETURN_TEXT_P(read_text_file(filename, 0, -1));
+	result = read_text_file(filename, 0, -1, if_not_exists);
+	if (result == NULL)
+		PG_RETURN_NULL();
+
+	PG_RETURN_TEXT_P(result);
 }
 
 /*
- * Read a section of a file, returning it as bytea
+ * Read the whole of a file, returning it as text
  */
 Datum
-pg_read_binary_file(PG_FUNCTION_ARGS)
+pg_read_file_all(PG_FUNCTION_ARGS)
+{
+	return read_file_all_wrapper(fcinfo);
+}
+
+/*
+ * Similar to pg_read_file_all, with IF NOT EXISTS option.
+ */
+Datum
+pg_read_file_all_extended(PG_FUNCTION_ARGS)
+{
+	return read_file_all_wrapper(fcinfo);
+}
+
+/*
+ * Wrapper for pg_read_binary_file and pg_read_binary_file_extended.
+ */
+static Datum
+read_binary_file_wrapper(PG_FUNCTION_ARGS)
 {
 	text	   *filename_t = PG_GETARG_TEXT_P(0);
 	int64		seek_offset = PG_GETARG_INT64(1);
 	int64		bytes_to_read = PG_GETARG_INT64(2);
 	char	   *filename;
+	bool		if_not_exists = false;
+	bytea	   *result;
 
 	if (!superuser())
 		ereport(ERROR,
 				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
 				 (errmsg("must be superuser to read files"))));
 
+	/* Check for option if_not_exists */
+	if (PG_NARGS() == 4 && !PG_ARGISNULL(3))
+		if_not_exists = PG_GETARG_BOOL(3);
+
 	filename = convert_and_check_filename(filename_t);
 
 	if (bytes_to_read < 0)
@@ -231,26 +309,76 @@ pg_read_binary_file(PG_FUNCTION_ARGS)
 				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 				 errmsg("requested length cannot be negative")));
 
-	PG_RETURN_BYTEA_P(read_binary_file(filename, seek_offset, bytes_to_read));
+	result = read_binary_file(filename, seek_offset,
+							  bytes_to_read, if_not_exists);
+	if (result == NULL)
+		PG_RETURN_NULL();
+	PG_RETURN_BYTEA_P(result);
 }
 
 /*
- * Read the whole of a file, returning it as bytea
+ * Read a section of a file, returning it as bytea
  */
 Datum
-pg_read_binary_file_all(PG_FUNCTION_ARGS)
+pg_read_binary_file(PG_FUNCTION_ARGS)
+{
+	return read_binary_file_wrapper(fcinfo);
+}
+
+/*
+ * Similar to pg_read_binary_file, with IF NOT EXISTS option.
+ */
+Datum
+pg_read_binary_file_extended(PG_FUNCTION_ARGS)
+{
+	return read_binary_file_wrapper(fcinfo);
+}
+
+/*
+ * Wrapper for pg_read_binary_file_all and pg_read_binary_file_all_extended.
+ */
+static Datum
+read_binary_file_all_wrapper(PG_FUNCTION_ARGS)
 {
 	text	   *filename_t = PG_GETARG_TEXT_P(0);
 	char	   *filename;
+	bool		if_not_exists = false;
+	text	   *result;
 
 	if (!superuser())
 		ereport(ERROR,
 				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
 				 (errmsg("must be superuser to read files"))));
 
+	/* Check for option if_not_exists */
+	if (PG_NARGS() == 2 && !PG_ARGISNULL(1))
+		if_not_exists = PG_GETARG_BOOL(1);
+
 	filename = convert_and_check_filename(filename_t);
 
-	PG_RETURN_BYTEA_P(read_binary_file(filename, 0, -1));
+	result = read_binary_file(filename, 0, -1, if_not_exists);
+	if (result == NULL)
+		PG_RETURN_NULL();
+
+	PG_RETURN_BYTEA_P(result);
+}
+
+/*
+ * Read the whole of a file, returning it as bytea
+ */
+Datum
+pg_read_binary_file_all(PG_FUNCTION_ARGS)
+{
+	return read_binary_file_all_wrapper(fcinfo);
+}
+
+/*
+ * Similar to pg_read_binary_file_all, with IF NOT EXISTS option.
+ */
+Datum
+pg_read_binary_file_all_extended(PG_FUNCTION_ARGS)
+{
+	return read_binary_file_all_wrapper(fcinfo);
 }
 
 /*
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index 8da1781..c805a9a 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -3189,12 +3189,20 @@ DATA(insert OID = 3307 ( pg_stat_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v 2 0
 DESCR("get information about file");
 DATA(insert OID = 2624 ( pg_read_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v 3 0 25 "25 20 20" _null_ _null_ _null_ _null_ _null_ pg_read_file _null_ _null_ _null_ ));
 DESCR("read text from a file");
+DATA(insert OID = 3293 ( pg_read_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v 4 0 25 "25 20 20 16" _null_ _null_ _null_ _null_ _null_ pg_read_file_extended _null_ _null_ _null_ ));
+DESCR("read text from a file");
 DATA(insert OID = 3826 ( pg_read_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v 1 0 25 "25" _null_ _null_ _null_ _null_ _null_ pg_read_file_all _null_ _null_ _null_ ));
 DESCR("read text from a file");
+DATA(insert OID = 3294 ( pg_read_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v 2 0 25 "25 16" _null_ _null_ _null_ _null_ _null_ pg_read_file_all_extended _null_ _null_ _null_ ));
+DESCR("read text from a file");
 DATA(insert OID = 3827 ( pg_read_binary_file	PGNSP PGUID 12 1 0 0 0 f f f f t f v 3 0 17 "25 20 20" _null_ _null_ _null_ _null_ _null_ pg_read_binary_file _null_ _null_ _null_ ));
 DESCR("read bytea from a file");
+DATA(insert OID = 3295 ( pg_read_binary_file	PGNSP PGUID 12 1 0 0 0 f f f f t f v 4 0 17 "25 20 20 16" _null_ _null_ _null_ _null_ _null_ pg_read_binary_file_extended _null_ _null_ _null_ ));
+DESCR("read bytea from a file");
 DATA(insert OID = 3828 ( pg_read_binary_file	PGNSP PGUID 12 1 0 0 0 f f f f t f v 1 0 17 "25" _null_ _null_ _null_ _null_ _null_ pg_read_binary_file_all _null_ _null_ _null_ ));
 DESCR("read bytea from a file");
+DATA(insert OID = 3296 ( pg_read_binary_file	PGNSP PGUID 12 1 0 0 0 f f f f t f v 2 0 17 "25 16" _null_ _null_ _null_ _null_ _null_ pg_read_binary_file_all_extended _null_ _null_ _null_ ));
+DESCR("read bytea from a file");
 DATA(insert OID = 2625 ( pg_ls_dir			PGNSP PGUID 12 1 1000 0 0 f f f f t t v 1 0 25 "25" _null_ _null_ _null_ _null_ _null_ pg_ls_dir _null_ _null_ _null_ ));
 DESCR("list all files in a directory");
 DATA(insert OID = 2626 ( pg_sleep			PGNSP PGUID 12 1 0 0 0 f f f f t f v 1 0 2278 "701" _null_ _null_ _null_ _null_ _null_ pg_sleep _null_ _null_ _null_ ));
diff --git a/src/include/utils/builtins.h b/src/include/utils/builtins.h
index e46650a..82d0e18 100644
--- a/src/include/utils/builtins.h
+++ b/src/include/utils/builtins.h
@@ -470,13 +470,19 @@ extern Datum pg_relation_filepath(PG_FUNCTION_ARGS);
 
 /* genfile.c */
 extern bytea *read_binary_file(const char *filename,
-				 int64 seek_offset, int64 bytes_to_read);
+							   int64 seek_offset,
+							   int64 bytes_to_read,
+							   bool if_not_exists);
 extern Datum pg_stat_file(PG_FUNCTION_ARGS);
 extern Datum pg_stat_file_extended(PG_FUNCTION_ARGS);
 extern Datum pg_read_file(PG_FUNCTION_ARGS);
+extern Datum pg_read_file_extended(PG_FUNCTION_ARGS);
 extern Datum pg_read_file_all(PG_FUNCTION_ARGS);
+extern Datum pg_read_file_all_extended(PG_FUNCTION_ARGS);
 extern Datum pg_read_binary_file(PG_FUNCTION_ARGS);
+extern Datum pg_read_binary_file_extended(PG_FUNCTION_ARGS);
 extern Datum pg_read_binary_file_all(PG_FUNCTION_ARGS);
+extern Datum pg_read_binary_file_all_extended(PG_FUNCTION_ARGS);
 extern Datum pg_ls_dir(PG_FUNCTION_ARGS);
 
 /* misc.c */
-- 
2.4.4

From 3299e47802759d362a034d718492420e3bea62dd Mon Sep 17 00:00:00 2001
From: Michael Paquier <michael@otacoo.com>
Date: Wed, 24 Jun 2015 10:59:16 +0900
Subject: [PATCH 4/8] Extend pg_ls_dir with include_dot_dirs and if_not_exists

If include_dot_dirs is set to true, "." and ".." are listed in the list
of files listed. If if_not_exists is true, an empty list of files is
returned to caller instead of erroring out if the folder specified does
not exist.
---
 doc/src/sgml/func.sgml          | 11 +++++--
 src/backend/utils/adt/genfile.c | 65 ++++++++++++++++++++++++++++++++++-------
 src/include/catalog/pg_proc.h   |  2 ++
 src/include/utils/builtins.h    |  1 +
 4 files changed, 66 insertions(+), 13 deletions(-)

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index edfea8b..3b5161a 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -17809,10 +17809,17 @@ postgres=# SELECT * FROM pg_xlogfile_name_offset(pg_stop_backup());
      <tbody>
       <row>
        <entry>
-        <literal><function>pg_ls_dir(<parameter>dirname</> <type>text</>)</function></literal>
+        <literal><function>pg_ls_dir(<parameter>dirname</> <type>text</> [, <parameter>if_not_exists</> <type>boolean</>, <parameter>include_dot_dirs</> <type>boolean</>] )</function></literal>
        </entry>
        <entry><type>setof text</type></entry>
-       <entry>List the contents of a directory</entry>
+       <entry>
+        List the contents of a directory.  If
+        <parameter>if_not_exists</parameter> is true, an empty result is
+        returned instead of an error. If <parameter>include_dot_dirs</>
+        is true, <quote>.</> and <quote>..</> are included as well in
+        the returned list, which is useful to distinguish an empty
+        and an non-existent directory.
+       </entry>
       </row>
       <row>
        <entry>
diff --git a/src/backend/utils/adt/genfile.c b/src/backend/utils/adt/genfile.c
index d45c66e..12866dd 100644
--- a/src/backend/utils/adt/genfile.c
+++ b/src/backend/utils/adt/genfile.c
@@ -35,6 +35,8 @@ typedef struct
 {
 	char	   *location;
 	DIR		   *dirdesc;
+	bool		include_dot_dirs;
+	bool		leave_early;
 } directory_fctx;
 
 
@@ -483,14 +485,15 @@ pg_stat_file(PG_FUNCTION_ARGS)
 
 
 /*
- * List a directory (returns the filenames only)
+ * Wrapper for pg_ls_dir and pg_ls_dir_extended.
  */
-Datum
-pg_ls_dir(PG_FUNCTION_ARGS)
+static Datum
+ls_dir_wrapper(PG_FUNCTION_ARGS)
 {
 	FuncCallContext *funcctx;
 	struct dirent *de;
 	directory_fctx *fctx;
+	MemoryContext	oldcontext;
 
 	if (!superuser())
 		ereport(ERROR,
@@ -499,7 +502,17 @@ pg_ls_dir(PG_FUNCTION_ARGS)
 
 	if (SRF_IS_FIRSTCALL())
 	{
-		MemoryContext oldcontext;
+		bool			if_not_exists = false;
+		bool			include_dot_dirs = false;
+
+		/* see if custom parameters have been passed down */
+		if (PG_NARGS() == 3)
+		{
+			if (!PG_ARGISNULL(1))
+				if_not_exists = PG_GETARG_BOOL(1);
+			if (!PG_ARGISNULL(2))
+				include_dot_dirs = PG_GETARG_BOOL(2);
+		}
 
 		funcctx = SRF_FIRSTCALL_INIT();
 		oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
@@ -507,14 +520,20 @@ pg_ls_dir(PG_FUNCTION_ARGS)
 		fctx = palloc(sizeof(directory_fctx));
 		fctx->location = convert_and_check_filename(PG_GETARG_TEXT_P(0));
 
+		fctx->include_dot_dirs = include_dot_dirs;
+		fctx->leave_early = false;
 		fctx->dirdesc = AllocateDir(fctx->location);
 
 		if (!fctx->dirdesc)
-			ereport(ERROR,
-					(errcode_for_file_access(),
-					 errmsg("could not open directory \"%s\": %m",
-							fctx->location)));
-
+		{
+			if (if_not_exists && errno == ENOENT)
+				fctx->leave_early = true;
+			else
+				ereport(ERROR,
+						(errcode_for_file_access(),
+						 errmsg("could not open directory \"%s\": %m",
+								fctx->location)));
+		}
 		funcctx->user_fctx = fctx;
 		MemoryContextSwitchTo(oldcontext);
 	}
@@ -522,10 +541,15 @@ pg_ls_dir(PG_FUNCTION_ARGS)
 	funcctx = SRF_PERCALL_SETUP();
 	fctx = (directory_fctx *) funcctx->user_fctx;
 
+	/* Leave earlier if needed */
+	if (fctx->leave_early)
+		SRF_RETURN_DONE(funcctx);
+
 	while ((de = ReadDir(fctx->dirdesc, fctx->location)) != NULL)
 	{
-		if (strcmp(de->d_name, ".") == 0 ||
-			strcmp(de->d_name, "..") == 0)
+		if (!fctx->include_dot_dirs &&
+			(strcmp(de->d_name, ".") == 0 ||
+			 strcmp(de->d_name, "..") == 0))
 			continue;
 
 		SRF_RETURN_NEXT(funcctx, CStringGetTextDatum(de->d_name));
@@ -535,3 +559,22 @@ pg_ls_dir(PG_FUNCTION_ARGS)
 
 	SRF_RETURN_DONE(funcctx);
 }
+
+/*
+ * List a directory (returns the filenames only)
+ */
+Datum
+pg_ls_dir(PG_FUNCTION_ARGS)
+{
+	return ls_dir_wrapper(fcinfo);
+}
+
+/*
+ * List a directory (can optionally return dot directories or
+ * use IF NOT EXISTS).
+ */
+Datum
+pg_ls_dir_extended(PG_FUNCTION_ARGS)
+{
+	return ls_dir_wrapper(fcinfo);
+}
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index c805a9a..b559572 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -3205,6 +3205,8 @@ DATA(insert OID = 3296 ( pg_read_binary_file	PGNSP PGUID 12 1 0 0 0 f f f f t f
 DESCR("read bytea from a file");
 DATA(insert OID = 2625 ( pg_ls_dir			PGNSP PGUID 12 1 1000 0 0 f f f f t t v 1 0 25 "25" _null_ _null_ _null_ _null_ _null_ pg_ls_dir _null_ _null_ _null_ ));
 DESCR("list all files in a directory");
+DATA(insert OID = 3297 ( pg_ls_dir			PGNSP PGUID 12 1 1000 0 0 f f f f t t v 3 0 25 "25 16 16" _null_ _null_ _null_ _null_ _null_ pg_ls_dir_extended _null_ _null_ _null_ ));
+DESCR("list all files in a directory");
 DATA(insert OID = 2626 ( pg_sleep			PGNSP PGUID 12 1 0 0 0 f f f f t f v 1 0 2278 "701" _null_ _null_ _null_ _null_ _null_ pg_sleep _null_ _null_ _null_ ));
 DESCR("sleep for the specified time in seconds");
 DATA(insert OID = 3935 ( pg_sleep_for			PGNSP PGUID 14 1 0 0 0 f f f f t f v 1 0 2278 "1186" _null_ _null_ _null_ _null_ _null_ "select pg_catalog.pg_sleep(extract(epoch from pg_catalog.clock_timestamp() operator(pg_catalog.+) $1) operator(pg_catalog.-) extract(epoch from pg_catalog.clock_timestamp()))" _null_ _null_ _null_ ));
diff --git a/src/include/utils/builtins.h b/src/include/utils/builtins.h
index 82d0e18..446cda6 100644
--- a/src/include/utils/builtins.h
+++ b/src/include/utils/builtins.h
@@ -484,6 +484,7 @@ extern Datum pg_read_binary_file_extended(PG_FUNCTION_ARGS);
 extern Datum pg_read_binary_file_all(PG_FUNCTION_ARGS);
 extern Datum pg_read_binary_file_all_extended(PG_FUNCTION_ARGS);
 extern Datum pg_ls_dir(PG_FUNCTION_ARGS);
+extern Datum pg_ls_dir_extended(PG_FUNCTION_ARGS);
 
 /* misc.c */
 extern Datum current_database(PG_FUNCTION_ARGS);
-- 
2.4.4

From fae83e948c7f8bd9f8f33ef6f088f8d7b5cf465a Mon Sep 17 00:00:00 2001
From: Michael Paquier <michael@otacoo.com>
Date: Wed, 24 Jun 2015 11:26:02 +0900
Subject: [PATCH 5/8] Add new column islink in pg_stat_file

This allows to detect if the file path evaluated is a synlink or not.
pg_stat_file is switched to use as well lstat to enable soft link
detection.
---
 doc/src/sgml/func.sgml          |  5 +++--
 src/backend/utils/adt/genfile.c | 15 +++++++++++----
 src/include/catalog/pg_proc.h   |  4 ++--
 3 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 3b5161a..20b91ab 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -17903,8 +17903,9 @@ SELECT convert_from(pg_read_binary_file('file_in_utf8.txt'), 'UTF8');
     <function>pg_stat_file</> returns a record containing the file
     size, last accessed time stamp, last modified time stamp,
     last file status change time stamp (Unix platforms only),
-    file creation time stamp (Windows only), and a <type>boolean</type>
-    indicating if it is a directory.  Typical usages include:
+    file creation time stamp (Windows only), a <type>boolean</type>
+    indicating if it is a directory, and a <type>boolean</type>
+    indicating if it is a symbolic link.  Typical usages include:
 <programlisting>
 SELECT * FROM pg_stat_file('filename');
 SELECT (pg_stat_file('filename')).modification;
diff --git a/src/backend/utils/adt/genfile.c b/src/backend/utils/adt/genfile.c
index 12866dd..456061b 100644
--- a/src/backend/utils/adt/genfile.c
+++ b/src/backend/utils/adt/genfile.c
@@ -392,8 +392,8 @@ stat_file_wrapper(PG_FUNCTION_ARGS)
 	text	   *filename_t = PG_GETARG_TEXT_P(0);
 	char	   *filename;
 	struct stat fst;
-	Datum		values[6];
-	bool		isnull[6];
+	Datum		values[7];
+	bool		isnull[7];
 	HeapTuple	tuple;
 	TupleDesc	tupdesc;
 	bool		if_not_exists = false;
@@ -410,7 +410,7 @@ stat_file_wrapper(PG_FUNCTION_ARGS)
 
 	filename = convert_and_check_filename(filename_t);
 
-	if (stat(filename, &fst) < 0)
+	if (lstat(filename, &fst) < 0)
 	{
 		if (if_not_exists && errno == ENOENT)
 			return_null = true;
@@ -424,7 +424,7 @@ stat_file_wrapper(PG_FUNCTION_ARGS)
 	 * This record type had better match the output parameters declared for me
 	 * in pg_proc.h.
 	 */
-	tupdesc = CreateTemplateTupleDesc(6, false);
+	tupdesc = CreateTemplateTupleDesc(7, false);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 1,
 					   "size", INT8OID, -1, 0);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 2,
@@ -437,6 +437,8 @@ stat_file_wrapper(PG_FUNCTION_ARGS)
 					   "creation", TIMESTAMPTZOID, -1, 0);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 6,
 					   "isdir", BOOLOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 7,
+					   "islink", BOOLOID, -1, 0);
 	BlessTupleDesc(tupdesc);
 
 	memset(isnull, return_null, sizeof(isnull));
@@ -455,6 +457,11 @@ stat_file_wrapper(PG_FUNCTION_ARGS)
 		values[4] = TimestampTzGetDatum(time_t_to_timestamptz(fst.st_ctime));
 #endif
 		values[5] = BoolGetDatum(S_ISDIR(fst.st_mode));
+#ifndef WIN32
+		values[6] = BoolGetDatum(S_ISLNK(fst.st_mode));
+#else
+		values[6] = BoolGetDatum(pgwin32_is_junction(filename));
+#endif
 	}
 
 	tuple = heap_form_tuple(tupdesc, values, isnull);
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index b559572..36d3e15 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -3183,9 +3183,9 @@ DESCR("reload configuration files");
 DATA(insert OID = 2622 ( pg_rotate_logfile		PGNSP PGUID 12 1 0 0 0 f f f f t f v 0 0 16 "" _null_ _null_ _null_ _null_ _null_ pg_rotate_logfile _null_ _null_ _null_ ));
 DESCR("rotate log file");
 
-DATA(insert OID = 2623 ( pg_stat_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v 1 0 2249 "25" "{25,20,1184,1184,1184,1184,16}" "{i,o,o,o,o,o,o}" "{filename,size,access,modification,change,creation,isdir}" _null_ _null_ pg_stat_file _null_ _null_ _null_ ));
+DATA(insert OID = 2623 ( pg_stat_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v 1 0 2249 "25" "{25,20,1184,1184,1184,1184,16,16}" "{i,o,o,o,o,o,o,o}" "{filename,size,access,modification,change,creation,isdir,islink}" _null_ _null_ pg_stat_file _null_ _null_ _null_ ));
 DESCR("get information about file");
-DATA(insert OID = 3307 ( pg_stat_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v 2 0 2249 "25 16" "{25,16,20,1184,1184,1184,1184,16}" "{i,i,o,o,o,o,o,o}" "{filename,if_not_exists,size,access,modification,change,creation,isdir}" _null_ _null_ pg_stat_file_extended _null_ _null_ _null_ ));
+DATA(insert OID = 3307 ( pg_stat_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v 2 0 2249 "25 16" "{25,16,20,1184,1184,1184,1184,16,16}" "{i,i,o,o,o,o,o,o,o}" "{filename,if_not_exists,size,access,modification,change,creation,isdir,islink}" _null_ _null_ pg_stat_file_extended _null_ _null_ _null_ ));
 DESCR("get information about file");
 DATA(insert OID = 2624 ( pg_read_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v 3 0 25 "25 20 20" _null_ _null_ _null_ _null_ _null_ pg_read_file _null_ _null_ _null_ ));
 DESCR("read text from a file");
-- 
2.4.4

From ef78401e6b136577fb1703a6820743ab404631b1 Mon Sep 17 00:00:00 2001
From: Michael Paquier <michael@otacoo.com>
Date: Wed, 24 Jun 2015 13:03:08 +0900
Subject: [PATCH 6/8] Add pg_readlink to get value of a symbolic link

This is similar to Posix's readlink, except that PostgreSQL restrictions
are applied to the source path queried, similarly to other functions of
genfile.c.
---
 doc/src/sgml/func.sgml          |  9 +++++++
 src/backend/utils/adt/genfile.c | 54 +++++++++++++++++++++++++++++++++++++++++
 src/include/catalog/pg_proc.h   |  2 ++
 src/include/utils/builtins.h    |  1 +
 4 files changed, 66 insertions(+)

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 20b91ab..81a8090 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -17855,6 +17855,15 @@ postgres=# SELECT * FROM pg_xlogfile_name_offset(pg_stop_backup());
         an error.
        </entry>
       </row>
+      <row>
+       <entry>
+        <literal><function>pg_readlink(<parameter>filename</> <type>text</>)</function></literal>
+       </entry>
+       <entry><type>text</type></entry>
+       <entry>
+        Return value of a symbolic link.
+       </entry>
+      </row>
      </tbody>
     </tgroup>
    </table>
diff --git a/src/backend/utils/adt/genfile.c b/src/backend/utils/adt/genfile.c
index 456061b..94ff7d6 100644
--- a/src/backend/utils/adt/genfile.c
+++ b/src/backend/utils/adt/genfile.c
@@ -585,3 +585,57 @@ pg_ls_dir_extended(PG_FUNCTION_ARGS)
 {
 	return ls_dir_wrapper(fcinfo);
 }
+
+
+/*
+ * pg_readlink - Find the real location of the provided symbolic link.
+ */
+Datum
+pg_readlink(PG_FUNCTION_ARGS)
+{
+	text	   *sourcepath_t = PG_GETARG_TEXT_P(0);
+	char	   *sourcepath;
+	char        targetpath[MAXPGPATH];
+	int			rllen;
+	bool		if_not_exists = false;
+
+	if (!superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 (errmsg("must be superuser to read files"))));
+
+	/* Check for option if_not_exists */
+	if (PG_NARGS() == 2 && !PG_ARGISNULL(1))
+		if_not_exists = PG_GETARG_BOOL(1);
+
+#if defined(HAVE_READLINK) || defined(WIN32)
+	sourcepath = convert_and_check_filename(sourcepath_t);
+
+	rllen = readlink(sourcepath, targetpath, sizeof(targetpath));
+	if (rllen < 0)
+	{
+		if (if_not_exists && errno == ENOENT)
+			PG_RETURN_NULL();
+		else
+			ereport(ERROR,
+					(errcode_for_file_access(),
+					 errmsg("could not read symbolic link \"%s\": %m",
+							sourcepath)));
+	}
+	if (rllen >= sizeof(targetpath))
+	{
+		ereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("symbolic link \"%s\" target is too long",
+						sourcepath)));
+	}
+	targetpath[rllen] = '\0';
+
+	PG_RETURN_TEXT_P(cstring_to_text(targetpath));
+#else
+	ereport(ERROR,
+			(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+			 errmsg("readline is not available on this platform")));
+	PG_RETURN_NULL();
+#endif
+}
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index 36d3e15..11dd80d 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -3207,6 +3207,8 @@ DATA(insert OID = 2625 ( pg_ls_dir			PGNSP PGUID 12 1 1000 0 0 f f f f t t v 1 0
 DESCR("list all files in a directory");
 DATA(insert OID = 3297 ( pg_ls_dir			PGNSP PGUID 12 1 1000 0 0 f f f f t t v 3 0 25 "25 16 16" _null_ _null_ _null_ _null_ _null_ pg_ls_dir_extended _null_ _null_ _null_ ));
 DESCR("list all files in a directory");
+DATA(insert OID = 3298 ( pg_readlink		PGNSP PGUID 12 1 0 0 0 f f f f t f s 1 0 25 "25" _null_ _null_ _null_ _null_ _null_ pg_readlink _null_ _null_ _null_ ));
+DESCR("read value of a symbolic link");
 DATA(insert OID = 2626 ( pg_sleep			PGNSP PGUID 12 1 0 0 0 f f f f t f v 1 0 2278 "701" _null_ _null_ _null_ _null_ _null_ pg_sleep _null_ _null_ _null_ ));
 DESCR("sleep for the specified time in seconds");
 DATA(insert OID = 3935 ( pg_sleep_for			PGNSP PGUID 14 1 0 0 0 f f f f t f v 1 0 2278 "1186" _null_ _null_ _null_ _null_ _null_ "select pg_catalog.pg_sleep(extract(epoch from pg_catalog.clock_timestamp() operator(pg_catalog.+) $1) operator(pg_catalog.-) extract(epoch from pg_catalog.clock_timestamp()))" _null_ _null_ _null_ ));
diff --git a/src/include/utils/builtins.h b/src/include/utils/builtins.h
index 446cda6..27a4fd8 100644
--- a/src/include/utils/builtins.h
+++ b/src/include/utils/builtins.h
@@ -485,6 +485,7 @@ extern Datum pg_read_binary_file_all(PG_FUNCTION_ARGS);
 extern Datum pg_read_binary_file_all_extended(PG_FUNCTION_ARGS);
 extern Datum pg_ls_dir(PG_FUNCTION_ARGS);
 extern Datum pg_ls_dir_extended(PG_FUNCTION_ARGS);
+extern Datum pg_readlink(PG_FUNCTION_ARGS);
 
 /* misc.c */
 extern Datum current_database(PG_FUNCTION_ARGS);
-- 
2.4.4

From e39f8148f2baa95a6426f46f407eeb0fa243a478 Mon Sep 17 00:00:00 2001
From: Michael Paquier <michael@otacoo.com>
Date: Tue, 23 Jun 2015 10:42:48 +0900
Subject: [PATCH 7/8] Add regression tests for pg_ls_dir and
 pg_read_[binary_]file

With the new options if_not_exists that have been added, this looks
worth adding.
---
 src/test/regress/expected/file.out | 84 ++++++++++++++++++++++++++++++++++++++
 src/test/regress/parallel_schedule |  3 ++
 src/test/regress/sql/file.sql      | 29 +++++++++++++
 3 files changed, 116 insertions(+)
 create mode 100644 src/test/regress/expected/file.out
 create mode 100644 src/test/regress/sql/file.sql

diff --git a/src/test/regress/expected/file.out b/src/test/regress/expected/file.out
new file mode 100644
index 0000000..0ddae30
--- /dev/null
+++ b/src/test/regress/expected/file.out
@@ -0,0 +1,84 @@
+--
+-- FILE
+--
+-- Tests of SQL functions interacting directly with files of PGDATA
+-- pg_read_file
+SELECT pg_read_file('postgresql.auto.conf', 0, 23); -- OK
+      pg_read_file       
+-------------------------
+ # Do not edit this file
+(1 row)
+
+SELECT pg_read_file('postgresql_not_exists', 0, 23); -- not OK
+ERROR:  could not open file "postgresql_not_exists" for reading: No such file or directory
+SELECT pg_read_file('postgresql_not_exists', 0, 23, false); -- not OK
+ERROR:  could not open file "postgresql_not_exists" for reading: No such file or directory
+SELECT pg_read_file('postgresql_not_exists', 0, 23, true); -- OK
+ pg_read_file 
+--------------
+ 
+(1 row)
+
+-- pg_read_binary_file
+SELECT pg_read_binary_file('postgresql.auto.conf', 0, 23); -- OK
+               pg_read_binary_file                
+--------------------------------------------------
+ \x2320446f206e6f74206564697420746869732066696c65
+(1 row)
+
+SELECT pg_read_binary_file('postgresql_not_exists', 0, 23); -- not OK
+ERROR:  could not open file "postgresql_not_exists" for reading: No such file or directory
+SELECT pg_read_binary_file('postgresql_not_exists', 0, 23, false); -- not OK
+ERROR:  could not open file "postgresql_not_exists" for reading: No such file or directory
+SELECT pg_read_binary_file('postgresql_not_exists', 0, 23, true); -- OK
+ pg_read_binary_file 
+---------------------
+ 
+(1 row)
+
+-- pg_ls_dir
+SELECT pg_ls_dir('postgresql.conf'); -- not OK, not a directory
+ERROR:  could not open directory "postgresql.conf": Not a directory
+SELECT pg_ls_dir('pg_twophase'); -- empty directory
+ pg_ls_dir 
+-----------
+(0 rows)
+
+SELECT pg_ls_dir('pg_twophase', true, true); -- OK, not empty list
+ pg_ls_dir 
+-----------
+ .
+ ..
+(2 rows)
+
+SELECT pg_ls_dir('pg_twophase', false, false); -- OK, empty list
+ pg_ls_dir 
+-----------
+(0 rows)
+
+SELECT pg_ls_dir('pg_twophase', false, true); -- OK, not empty list
+ pg_ls_dir 
+-----------
+ .
+ ..
+(2 rows)
+
+SELECT pg_ls_dir('pg_twophase', true, false); -- OK, empty list
+ pg_ls_dir 
+-----------
+(0 rows)
+
+SELECT pg_ls_dir('postgresql_not_exists', false, true); -- not OK
+ERROR:  could not open directory "postgresql_not_exists": No such file or directory
+SELECT pg_ls_dir('postgresql_not_exists', false, false); -- not OK
+ERROR:  could not open directory "postgresql_not_exists": No such file or directory
+SELECT pg_ls_dir('postgresql_not_exists', true, true); -- OK, empty list
+ pg_ls_dir 
+-----------
+(0 rows)
+
+SELECT pg_ls_dir('postgresql_not_exists', true, false); -- OK, empty list
+ pg_ls_dir 
+-----------
+(0 rows)
+
diff --git a/src/test/regress/parallel_schedule b/src/test/regress/parallel_schedule
index 91780cd..b1739fa 100644
--- a/src/test/regress/parallel_schedule
+++ b/src/test/regress/parallel_schedule
@@ -108,5 +108,8 @@ test: plancache limit plpgsql copy2 temp domain rangefuncs prepare without_oid c
 # event triggers cannot run concurrently with any test that runs DDL
 test: event_trigger
 
+# Files read during this test may be modified in parallel by other tests
+test: file
+
 # run stats by itself because its delay may be insufficient under heavy load
 test: stats
diff --git a/src/test/regress/sql/file.sql b/src/test/regress/sql/file.sql
new file mode 100644
index 0000000..a0238f2
--- /dev/null
+++ b/src/test/regress/sql/file.sql
@@ -0,0 +1,29 @@
+--
+-- FILE
+--
+
+-- Tests of SQL functions interacting directly with files of PGDATA
+
+-- pg_read_file
+SELECT pg_read_file('postgresql.auto.conf', 0, 23); -- OK
+SELECT pg_read_file('postgresql_not_exists', 0, 23); -- not OK
+SELECT pg_read_file('postgresql_not_exists', 0, 23, false); -- not OK
+SELECT pg_read_file('postgresql_not_exists', 0, 23, true); -- OK
+
+-- pg_read_binary_file
+SELECT pg_read_binary_file('postgresql.auto.conf', 0, 23); -- OK
+SELECT pg_read_binary_file('postgresql_not_exists', 0, 23); -- not OK
+SELECT pg_read_binary_file('postgresql_not_exists', 0, 23, false); -- not OK
+SELECT pg_read_binary_file('postgresql_not_exists', 0, 23, true); -- OK
+
+-- pg_ls_dir
+SELECT pg_ls_dir('postgresql.conf'); -- not OK, not a directory
+SELECT pg_ls_dir('pg_twophase'); -- empty directory
+SELECT pg_ls_dir('pg_twophase', true, true); -- OK, not empty list
+SELECT pg_ls_dir('pg_twophase', false, false); -- OK, empty list
+SELECT pg_ls_dir('pg_twophase', false, true); -- OK, not empty list
+SELECT pg_ls_dir('pg_twophase', true, false); -- OK, empty list
+SELECT pg_ls_dir('postgresql_not_exists', false, true); -- not OK
+SELECT pg_ls_dir('postgresql_not_exists', false, false); -- not OK
+SELECT pg_ls_dir('postgresql_not_exists', true, true); -- OK, empty list
+SELECT pg_ls_dir('postgresql_not_exists', true, false); -- OK, empty list
-- 
2.4.4

From 370cc091048a2259e633ca65473ed1a835e13451 Mon Sep 17 00:00:00 2001
From: Michael Paquier <michael@otacoo.com>
Date: Wed, 24 Jun 2015 15:10:16 +0900
Subject: [PATCH 8/8] Fix symlink usage in pg_rewind

Make use of pg_readlink to determine where a symlink in a source PGDATA
streamed is from. Also remove restrictions related to symlink comparisons
on source and target instances, those need to be only limited to
tablespaces.
---
 src/bin/pg_rewind/file_ops.c    |  2 ++
 src/bin/pg_rewind/filemap.c     | 11 ++-----
 src/bin/pg_rewind/filemap.h     |  1 +
 src/bin/pg_rewind/libpq_fetch.c | 63 +++++++++++++++++++++++++----------------
 4 files changed, 45 insertions(+), 32 deletions(-)

diff --git a/src/bin/pg_rewind/file_ops.c b/src/bin/pg_rewind/file_ops.c
index c2d8aa1..29ddb1d 100644
--- a/src/bin/pg_rewind/file_ops.c
+++ b/src/bin/pg_rewind/file_ops.c
@@ -139,6 +139,7 @@ remove_target(file_entry_t *entry)
 			remove_target_file(entry->path);
 			break;
 
+		case FILE_TYPE_TABLESPACE:
 		case FILE_TYPE_SYMLINK:
 			remove_target_symlink(entry->path);
 			break;
@@ -156,6 +157,7 @@ create_target(file_entry_t *entry)
 			create_target_dir(entry->path);
 			break;
 
+		case FILE_TYPE_TABLESPACE:
 		case FILE_TYPE_SYMLINK:
 			create_target_symlink(entry->path, entry->link_target);
 			break;
diff --git a/src/bin/pg_rewind/filemap.c b/src/bin/pg_rewind/filemap.c
index 05eff68..6ef2342 100644
--- a/src/bin/pg_rewind/filemap.c
+++ b/src/bin/pg_rewind/filemap.c
@@ -112,12 +112,6 @@ process_source_file(const char *path, file_type_t type, size_t newsize,
 	switch (type)
 	{
 		case FILE_TYPE_DIRECTORY:
-			if (exists && !S_ISDIR(statbuf.st_mode))
-			{
-				/* it's a directory in source, but not in target. Strange.. */
-				pg_fatal("\"%s\" is not a directory\n", localpath);
-			}
-
 			if (!exists)
 				action = FILE_ACTION_CREATE;
 			else
@@ -125,7 +119,7 @@ process_source_file(const char *path, file_type_t type, size_t newsize,
 			oldsize = 0;
 			break;
 
-		case FILE_TYPE_SYMLINK:
+		case FILE_TYPE_TABLESPACE:
 			if (exists &&
 #ifndef WIN32
 				!S_ISLNK(statbuf.st_mode)
@@ -140,7 +134,8 @@ process_source_file(const char *path, file_type_t type, size_t newsize,
 				 */
 				pg_fatal("\"%s\" is not a symbolic link\n", localpath);
 			}
-
+			/* fallback to default */
+		case FILE_TYPE_SYMLINK:
 			if (!exists)
 				action = FILE_ACTION_CREATE;
 			else
diff --git a/src/bin/pg_rewind/filemap.h b/src/bin/pg_rewind/filemap.h
index 9943ec5..35540d6 100644
--- a/src/bin/pg_rewind/filemap.h
+++ b/src/bin/pg_rewind/filemap.h
@@ -36,6 +36,7 @@ typedef enum
 {
 	FILE_TYPE_REGULAR,
 	FILE_TYPE_DIRECTORY,
+	FILE_TYPE_TABLESPACE,
 	FILE_TYPE_SYMLINK
 } file_type_t;
 
diff --git a/src/bin/pg_rewind/libpq_fetch.c b/src/bin/pg_rewind/libpq_fetch.c
index df71069..49950b9 100644
--- a/src/bin/pg_rewind/libpq_fetch.c
+++ b/src/bin/pg_rewind/libpq_fetch.c
@@ -140,30 +140,28 @@ libpqProcessFileList(void)
 	 * Create a recursive directory listing of the whole data directory.
 	 *
 	 * The WITH RECURSIVE part does most of the work. The second part gets the
-	 * targets of the symlinks in pg_tblspc directory.
-	 *
-	 * XXX: There is no backend function to get a symbolic link's target in
-	 * general, so if the admin has put any custom symbolic links in the data
-	 * directory, they won't be copied correctly.
+	 * targets of the symlinks in the data directory.
 	 */
 	sql =
 		"WITH RECURSIVE files (path, filename, size, isdir) AS (\n"
-		"  SELECT '' AS path, filename, size, isdir FROM\n"
-		"  (SELECT pg_ls_dir('.') AS filename) AS fn,\n"
-		"        pg_stat_file(fn.filename) AS this\n"
+		"  SELECT '' AS path, filename, size, isdir, islink FROM\n"
+		"  (SELECT pg_ls_dir('.', true, false) AS filename) AS fn,\n"
+		"        pg_stat_file(fn.filename, true) AS this\n"
+		"    WHERE this.size IS NOT NULL\n"
 		"  UNION ALL\n"
 		"  SELECT parent.path || parent.filename || '/' AS path,\n"
-		"         fn, this.size, this.isdir\n"
+		"         fn, this.size, this.isdir, this.islink\n"
 		"  FROM files AS parent,\n"
-		"       pg_ls_dir(parent.path || parent.filename) AS fn,\n"
-		"       pg_stat_file(parent.path || parent.filename || '/' || fn) AS this\n"
-		"       WHERE parent.isdir = 't'\n"
-		")\n"
-		"SELECT path || filename, size, isdir,\n"
-		"       pg_tablespace_location(pg_tablespace.oid) AS link_target\n"
-		"FROM files\n"
-		"LEFT OUTER JOIN pg_tablespace ON files.path = 'pg_tblspc/'\n"
-		"                             AND oid::text = files.filename\n";
+		"       pg_ls_dir(parent.path || parent.filename, true, false) AS fn,\n"
+		"       pg_stat_file(parent.path || parent.filename || '/' || fn, true)\n"
+		"              AS this\n"
+		"       WHERE parent.isdir = 't' AND\n"
+		"	          this.size IS NOT NULL)\n"
+		"SELECT path || filename AS file_path, size, isdir, islink,\n"
+		"       path = 'pg_tblspc/' AS istblspc,\n"
+		"       CASE WHEN islink THEN pg_readlink(path || filename)\n"
+		"            ELSE NULL END AS link_target\n"
+		"FROM files\n";
 	res = PQexec(conn, sql);
 
 	if (PQresultStatus(res) != PGRES_TUPLES_OK)
@@ -171,7 +169,7 @@ libpqProcessFileList(void)
 				 PQresultErrorMessage(res));
 
 	/* sanity check the result set */
-	if (PQnfields(res) != 4)
+	if (PQnfields(res) != 6)
 		pg_fatal("unexpected result set while fetching file list\n");
 
 	/* Read result to local variables */
@@ -180,10 +178,14 @@ libpqProcessFileList(void)
 		char	   *path = PQgetvalue(res, i, 0);
 		int			filesize = atoi(PQgetvalue(res, i, 1));
 		bool		isdir = (strcmp(PQgetvalue(res, i, 2), "t") == 0);
-		char	   *link_target = PQgetvalue(res, i, 3);
+		bool		islink = (strcmp(PQgetvalue(res, i, 3), "t") == 0);
+		bool		istblspc = (strcmp(PQgetvalue(res, i, 4), "t") == 0);
+		char	   *link_target = PQgetvalue(res, i, 5);
 		file_type_t type;
 
-		if (link_target[0])
+		if (istblspc)
+			type = FILE_TYPE_TABLESPACE;
+		else if (islink)
 			type = FILE_TYPE_SYMLINK;
 		else if (isdir)
 			type = FILE_TYPE_DIRECTORY;
@@ -259,8 +261,7 @@ receiveFileChunks(const char *sql)
 		}
 
 		if (PQgetisnull(res, 0, 0) ||
-			PQgetisnull(res, 0, 1) ||
-			PQgetisnull(res, 0, 2))
+			PQgetisnull(res, 0, 1))
 		{
 			pg_fatal("unexpected null values in result while fetching remote files\n");
 		}
@@ -278,6 +279,20 @@ receiveFileChunks(const char *sql)
 		memcpy(filename, PQgetvalue(res, 0, 0), filenamelen);
 		filename[filenamelen] = '\0';
 
+		/*
+		 * It may be possible that a file has been deleted on remote side after
+		 * creating the file map. In this case simply ignore it and move on.
+		 */
+		if (PQgetisnull(res, 0, 2))
+		{
+			pg_log(PG_DEBUG,
+				   "received NULL chunk for file \"%s\", file has been deleted\n",
+				   filename);
+			pg_free(filename);
+			PQclear(res);
+			continue;
+		}
+
 		chunk = PQgetvalue(res, 0, 2);
 
 		pg_log(PG_DEBUG, "received chunk for file \"%s\", offset %d, size %d\n",
@@ -445,7 +460,7 @@ libpq_executeFileMap(filemap_t *map)
 	 */
 	sql =
 		"SELECT path, begin, \n"
-		"  pg_read_binary_file(path, begin, len) AS chunk\n"
+		"  pg_read_binary_file(path, begin, len, true) AS chunk\n"
 		"FROM fetchchunks\n";
 
 	receiveFileChunks(sql);
-- 
2.4.4

diff --git a/src/bin/pg_rewind/copy_fetch.c b/src/bin/pg_rewind/copy_fetch.c
index 224fad1..ef830ac 100644
--- a/src/bin/pg_rewind/copy_fetch.c
+++ b/src/bin/pg_rewind/copy_fetch.c
@@ -174,7 +174,8 @@ copy_file_range(const char *path, off_t begin, off_t end, bool trunc)
 	if (lseek(srcfd, begin, SEEK_SET) == -1)
 		pg_fatal("could not seek in source file: %s\n", strerror(errno));
 
-	open_target_file(path, trunc);
+	if (!open_target_file(path, trunc))
+		return;
 
 	while (end - begin > 0)
 	{
diff --git a/src/bin/pg_rewind/file_ops.c b/src/bin/pg_rewind/file_ops.c
index c2d8aa1..1f68855 100644
--- a/src/bin/pg_rewind/file_ops.c
+++ b/src/bin/pg_rewind/file_ops.c
@@ -40,17 +40,17 @@ static void remove_target_symlink(const char *path);
  * Open a target file for writing. If 'trunc' is true and the file already
  * exists, it will be truncated.
  */
-void
+bool
 open_target_file(const char *path, bool trunc)
 {
 	int			mode;
 
 	if (dry_run)
-		return;
+		return true;
 
 	if (dstfd != -1 && !trunc &&
 		strcmp(path, &dstpath[strlen(datadir_target) + 1]) == 0)
-		return;					/* already open */
+		return true;				/* already open */
 
 	close_target_file();
 
@@ -60,9 +60,19 @@ open_target_file(const char *path, bool trunc)
 	if (trunc)
 		mode |= O_TRUNC;
 	dstfd = open(dstpath, mode, 0600);
+
+	/* ignore errors for unreadable files */
+	if (dstfd < 0 && errno == EACCES)
+	{
+		pg_log(PG_PROGRESS, "could not open target file \"%s\", bypassing: %s\n",
+			   dstpath, strerror(errno));
+		return false;
+	}
 	if (dstfd < 0)
 		pg_fatal("could not open target file \"%s\": %s\n",
 				 dstpath, strerror(errno));
+
+	return true;
 }
 
 /*
diff --git a/src/bin/pg_rewind/file_ops.h b/src/bin/pg_rewind/file_ops.h
index f68c71d..e437cb1 100644
--- a/src/bin/pg_rewind/file_ops.h
+++ b/src/bin/pg_rewind/file_ops.h
@@ -12,7 +12,7 @@
 
 #include "filemap.h"
 
-extern void open_target_file(const char *path, bool trunc);
+extern bool open_target_file(const char *path, bool trunc);
 extern void write_target_range(char *buf, off_t begin, size_t size);
 extern void close_target_file(void);
 extern void truncate_target_file(const char *path, off_t newsize);
diff --git a/src/bin/pg_rewind/libpq_fetch.c b/src/bin/pg_rewind/libpq_fetch.c
index df71069..41c096b 100644
--- a/src/bin/pg_rewind/libpq_fetch.c
+++ b/src/bin/pg_rewind/libpq_fetch.c
@@ -283,7 +283,8 @@ receiveFileChunks(const char *sql)
 		pg_log(PG_DEBUG, "received chunk for file \"%s\", offset %d, size %d\n",
 			   filename, chunkoff, chunksize);
 
-		open_target_file(filename, false);
+		if (!open_target_file(filename, false))
+			continue;
 
 		write_target_range(chunk, chunkoff, chunksize);
 
@@ -406,8 +407,8 @@ libpq_executeFileMap(filemap_t *map)
 
 			case FILE_ACTION_COPY:
 				/* Truncate the old file out of the way, if any */
-				open_target_file(entry->path, true);
-				fetch_file_range(entry->path, 0, entry->newsize);
+				if (open_target_file(entry->path, true))
+					fetch_file_range(entry->path, 0, entry->newsize);
 				break;
 
 			case FILE_ACTION_TRUNCATE:
diff --git a/src/bin/pg_rewind/pg_rewind.c b/src/bin/pg_rewind/pg_rewind.c
index 032301f..77dddbe 100644
--- a/src/bin/pg_rewind/pg_rewind.c
+++ b/src/bin/pg_rewind/pg_rewind.c
@@ -496,7 +496,8 @@ createBackupLabel(XLogRecPtr startpoint, TimeLineID starttli, XLogRecPtr checkpo
 		pg_fatal("backup label buffer too small\n");	/* shouldn't happen */
 
 	/* TODO: move old file out of the way, if any. */
-	open_target_file("backup_label", true);		/* BACKUP_LABEL_FILE */
+	if (!open_target_file("backup_label", true))		/* BACKUP_LABEL_FILE */
+		pg_fatal("failed update of backup_label\n");
 	write_target_range(buf, 0, len);
 }
 
@@ -557,7 +558,8 @@ updateControlFile(ControlFileData *ControlFile)
 	memset(buffer, 0, PG_CONTROL_SIZE);
 	memcpy(buffer, ControlFile, sizeof(ControlFileData));
 
-	open_target_file("global/pg_control", false);
+	if (!open_target_file("global/pg_control", false))
+		pg_fatal("failed update of global/pg_control");
 
 	write_target_range(buffer, 0, PG_CONTROL_SIZE);
 
diff --git a/src/bin/pg_rewind/t/003_extrafiles.pl b/src/bin/pg_rewind/t/003_extrafiles.pl
index 9a95268..95b42de 100644
--- a/src/bin/pg_rewind/t/003_extrafiles.pl
+++ b/src/bin/pg_rewind/t/003_extrafiles.pl
@@ -51,6 +51,17 @@ sub run_test
 	  "$test_master_datadir/tst_master_dir/master_subdir/master_file3",
 	  "in master3";
 
+	# Create a read-only file on both nodes
+	append_to_file
+	  "$test_standby_datadir/read_only_file",
+	  "read-only file in both4";
+	chmod 0400, "$test_standby_datadir/read_only_file";
+	append_to_file
+	  "$test_master_datadir/read_only_file",
+	  "read-only file in both4";
+	chmod 0400, "$test_standby_datadir/read_only_file";
+	chmod 0400, "$test_master_datadir/read_only_file";
+
 	RewindTest::promote_standby();
 	RewindTest::run_pg_rewind($test_mode);
 

From 378bd8af5c27e7e20b038f05b693b95e9871ef0b Mon Sep 17 00:00:00 2001
From: Michael Paquier <michael@otacoo.com>
Date: Mon, 29 Jun 2015 13:38:03 +0900
Subject: [PATCH 1/5] Fix some typos and an incorrect naming introduced by
 cb2acb1

---
 doc/src/sgml/func.sgml        | 4 ++--
 src/include/catalog/pg_proc.h | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index d49cd43..8b28e29 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -17851,7 +17851,7 @@ postgres=# SELECT * FROM pg_xlogfile_name_offset(pg_stop_backup());
 
    <para>
     All of these functions take an optional <parameter>missing_ok</> parameter,
-    which specifies the behaviour when the file or directory does not exist.
+    which specifies the behavior when the file or directory does not exist.
     If <literal>true</literal>, the function returns NULL (except
     <function>pg_ls_dir</>, which returns an empty result set). If
     <literal>false</>, an error is raised. The default is <literal>false</>.
@@ -17867,7 +17867,7 @@ postgres=# SELECT * FROM pg_xlogfile_name_offset(pg_stop_backup());
     included in the result set. The default is to exclude them
     (<literal>false</>), but including them can be useful when
     <parameter>missing_ok</> is <literal>true</literal>, to distinguish an
-    empty directory from an non-existent directory.
+    empty directory from a non-existent directory.
    </para>
 
    <indexterm>
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index 3a40fa6..be3a8fb 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -3183,7 +3183,7 @@ DESCR("rotate log file");
 
 DATA(insert OID = 2623 ( pg_stat_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v 1 0 2249 "25" "{25,20,1184,1184,1184,1184,16}" "{i,o,o,o,o,o,o}" "{filename,size,access,modification,change,creation,isdir}" _null_ _null_ pg_stat_file_1arg _null_ _null_ _null_ ));
 DESCR("get information about file");
-DATA(insert OID = 3307 ( pg_stat_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v 2 0 2249 "25 16" "{25,16,20,1184,1184,1184,1184,16}" "{i,i,o,o,o,o,o,o}" "{filename,if_not_exists,size,access,modification,change,creation,isdir}" _null_ _null_ pg_stat_file _null_ _null_ _null_ ));
+DATA(insert OID = 3307 ( pg_stat_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v 2 0 2249 "25 16" "{25,16,20,1184,1184,1184,1184,16}" "{i,i,o,o,o,o,o,o}" "{filename,missing_ok,size,access,modification,change,creation,isdir}" _null_ _null_ pg_stat_file _null_ _null_ _null_ ));
 DESCR("get information about file");
 DATA(insert OID = 2624 ( pg_read_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v 3 0 25 "25 20 20" _null_ _null_ _null_ _null_ _null_ pg_read_file_off_len _null_ _null_ _null_ ));
 DESCR("read text from a file");
-- 
2.4.5

From 9ae79930461a9024d01a878bdf63bfc4cd143c0d Mon Sep 17 00:00:00 2001
From: Michael Paquier <michael@otacoo.com>
Date: Wed, 24 Jun 2015 11:26:02 +0900
Subject: [PATCH 2/5] Add new column islink in pg_stat_file

This allows to detect if the file path evaluated is a symlink or not.
pg_stat_file is switched to use as well lstat to enable soft link
detection.
---
 doc/src/sgml/func.sgml          |  5 +++--
 src/backend/utils/adt/genfile.c | 15 +++++++++++----
 src/include/catalog/pg_proc.h   |  5 ++---
 3 files changed, 16 insertions(+), 9 deletions(-)

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 8b28e29..67e1626 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -17905,8 +17905,9 @@ SELECT convert_from(pg_read_binary_file('file_in_utf8.txt'), 'UTF8');
     <function>pg_stat_file</> returns a record containing the file
     size, last accessed time stamp, last modified time stamp,
     last file status change time stamp (Unix platforms only),
-    file creation time stamp (Windows only), and a <type>boolean</type>
-    indicating if it is a directory.  Typical usages include:
+    file creation time stamp (Windows only), a <type>boolean</type>
+    indicating if it is a directory, and a <type>boolean</type>
+    indicating if it is a symbolic link.  Typical usages include:
 <programlisting>
 SELECT * FROM pg_stat_file('filename');
 SELECT (pg_stat_file('filename')).modification;
diff --git a/src/backend/utils/adt/genfile.c b/src/backend/utils/adt/genfile.c
index c4eb10d..df8ae88 100644
--- a/src/backend/utils/adt/genfile.c
+++ b/src/backend/utils/adt/genfile.c
@@ -306,8 +306,8 @@ pg_stat_file(PG_FUNCTION_ARGS)
 	text	   *filename_t = PG_GETARG_TEXT_P(0);
 	char	   *filename;
 	struct stat fst;
-	Datum		values[6];
-	bool		isnull[6];
+	Datum		values[7];
+	bool		isnull[7];
 	HeapTuple	tuple;
 	TupleDesc	tupdesc;
 	bool		missing_ok = false;
@@ -323,7 +323,7 @@ pg_stat_file(PG_FUNCTION_ARGS)
 
 	filename = convert_and_check_filename(filename_t);
 
-	if (stat(filename, &fst) < 0)
+	if (lstat(filename, &fst) < 0)
 	{
 		if (missing_ok && errno == ENOENT)
 			PG_RETURN_NULL();
@@ -337,7 +337,7 @@ pg_stat_file(PG_FUNCTION_ARGS)
 	 * This record type had better match the output parameters declared for me
 	 * in pg_proc.h.
 	 */
-	tupdesc = CreateTemplateTupleDesc(6, false);
+	tupdesc = CreateTemplateTupleDesc(7, false);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 1,
 					   "size", INT8OID, -1, 0);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 2,
@@ -350,6 +350,8 @@ pg_stat_file(PG_FUNCTION_ARGS)
 					   "creation", TIMESTAMPTZOID, -1, 0);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 6,
 					   "isdir", BOOLOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 7,
+					   "islink", BOOLOID, -1, 0);
 	BlessTupleDesc(tupdesc);
 
 	memset(isnull, false, sizeof(isnull));
@@ -366,6 +368,11 @@ pg_stat_file(PG_FUNCTION_ARGS)
 	values[4] = TimestampTzGetDatum(time_t_to_timestamptz(fst.st_ctime));
 #endif
 	values[5] = BoolGetDatum(S_ISDIR(fst.st_mode));
+#ifndef WIN32
+	values[6] = BoolGetDatum(S_ISLNK(fst.st_mode));
+#else
+	values[6] = BoolGetDatum(pgwin32_is_junction(filename));
+#endif
 
 	tuple = heap_form_tuple(tupdesc, values, isnull);
 
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index be3a8fb..f6abd74 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -3180,10 +3180,9 @@ DATA(insert OID = 2621 ( pg_reload_conf			PGNSP PGUID 12 1 0 0 0 f f f f t f v 0
 DESCR("reload configuration files");
 DATA(insert OID = 2622 ( pg_rotate_logfile		PGNSP PGUID 12 1 0 0 0 f f f f t f v 0 0 16 "" _null_ _null_ _null_ _null_ _null_ pg_rotate_logfile _null_ _null_ _null_ ));
 DESCR("rotate log file");
-
-DATA(insert OID = 2623 ( pg_stat_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v 1 0 2249 "25" "{25,20,1184,1184,1184,1184,16}" "{i,o,o,o,o,o,o}" "{filename,size,access,modification,change,creation,isdir}" _null_ _null_ pg_stat_file_1arg _null_ _null_ _null_ ));
+DATA(insert OID = 2623 ( pg_stat_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v 1 0 2249 "25" "{25,20,1184,1184,1184,1184,16,16}" "{i,o,o,o,o,o,o,o}" "{filename,size,access,modification,change,creation,isdir,islink}" _null_ _null_ pg_stat_file_1arg _null_ _null_ _null_ ));
 DESCR("get information about file");
-DATA(insert OID = 3307 ( pg_stat_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v 2 0 2249 "25 16" "{25,16,20,1184,1184,1184,1184,16}" "{i,i,o,o,o,o,o,o}" "{filename,missing_ok,size,access,modification,change,creation,isdir}" _null_ _null_ pg_stat_file _null_ _null_ _null_ ));
+DATA(insert OID = 3307 ( pg_stat_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v 2 0 2249 "25 16" "{25,16,20,1184,1184,1184,1184,16,16}" "{i,i,o,o,o,o,o,o,o}" "{filename,missing_ok,size,access,modification,change,creation,isdir,islink}" _null_ _null_ pg_stat_file _null_ _null_ _null_ ));
 DESCR("get information about file");
 DATA(insert OID = 2624 ( pg_read_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v 3 0 25 "25 20 20" _null_ _null_ _null_ _null_ _null_ pg_read_file_off_len _null_ _null_ _null_ ));
 DESCR("read text from a file");
-- 
2.4.5

From 0ea59fb774e61e60def14f5a3470429695ad6adc Mon Sep 17 00:00:00 2001
From: Michael Paquier <michael@otacoo.com>
Date: Mon, 29 Jun 2015 14:40:20 +0900
Subject: [PATCH 3/5] Add pg_readlink to get value of a symbolic link

This is similar to Posix's readlink, except that PostgreSQL restrictions
are applied to the source path queried, similarly to other functions of
genfile.c.
---
 doc/src/sgml/func.sgml          |  9 ++++++
 src/backend/utils/adt/genfile.c | 66 +++++++++++++++++++++++++++++++++++++++++
 src/include/catalog/pg_proc.h   |  4 +++
 src/include/utils/builtins.h    |  2 ++
 4 files changed, 81 insertions(+)

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 67e1626..80a4f26 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -17845,6 +17845,15 @@ postgres=# SELECT * FROM pg_xlogfile_name_offset(pg_stop_backup());
         Return information about a file.
        </entry>
       </row>
+      <row>
+       <entry>
+        <literal><function>pg_readlink(<parameter>filename</> <type>text</>[, <parameter>missing_ok</> <type>boolean</type>])</function></literal>
+       </entry>
+       <entry><type>text</type></entry>
+       <entry>
+        Return value of a symbolic link.
+       </entry>
+      </row>
      </tbody>
     </tgroup>
    </table>
diff --git a/src/backend/utils/adt/genfile.c b/src/backend/utils/adt/genfile.c
index df8ae88..a0f8d7b 100644
--- a/src/backend/utils/adt/genfile.c
+++ b/src/backend/utils/adt/genfile.c
@@ -480,3 +480,69 @@ pg_ls_dir_1arg(PG_FUNCTION_ARGS)
 {
 	return pg_ls_dir(fcinfo);
 }
+
+
+/*
+ * pg_readlink - Find the real location of the provided symbolic link.
+ */
+Datum
+pg_readlink(PG_FUNCTION_ARGS)
+{
+	text	   *sourcepath_t = PG_GETARG_TEXT_P(0);
+	char	   *sourcepath;
+	char        targetpath[MAXPGPATH];
+	int			rllen;
+	bool		missing_ok = false;
+
+	if (!superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 (errmsg("must be superuser to read files"))));
+
+	if (PG_NARGS() == 2)
+		missing_ok = PG_GETARG_BOOL(1);
+
+#if defined(HAVE_READLINK) || defined(WIN32)
+	sourcepath = convert_and_check_filename(sourcepath_t);
+
+	rllen = readlink(sourcepath, targetpath, sizeof(targetpath));
+	if (rllen < 0)
+	{
+		if (missing_ok && errno == ENOENT)
+			PG_RETURN_NULL();
+		else
+			ereport(ERROR,
+					(errcode_for_file_access(),
+					 errmsg("could not read symbolic link \"%s\": %m",
+							sourcepath)));
+	}
+	if (rllen >= sizeof(targetpath))
+	{
+		ereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("symbolic link \"%s\" target is too long",
+						sourcepath)));
+	}
+	targetpath[rllen] = '\0';
+
+	PG_RETURN_TEXT_P(cstring_to_text(targetpath));
+#else
+	ereport(ERROR,
+			(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+			 errmsg("symbolic links are not supported by this platform")));
+	PG_RETURN_NULL();
+#endif
+}
+
+/*
+ * pg_readlink (1 argument version)
+ *
+ * note: this wrapper is necessary to pass the sanity check in opr_sanity,
+ * which checks that all built-in functions that share the implementing C
+ * function take the same number of arguments
+ */
+Datum
+pg_readlink_1arg(PG_FUNCTION_ARGS)
+{
+	return pg_readlink(fcinfo);
+}
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index f6abd74..f9c6176 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -3200,6 +3200,10 @@ DATA(insert OID = 2625 ( pg_ls_dir			PGNSP PGUID 12 1 1000 0 0 f f f f t t v 1 0
 DESCR("list all files in a directory");
 DATA(insert OID = 3297 ( pg_ls_dir			PGNSP PGUID 12 1 1000 0 0 f f f f t t v 3 0 25 "25 16 16" _null_ _null_ _null_ _null_ _null_ pg_ls_dir _null_ _null_ _null_ ));
 DESCR("list all files in a directory");
+DATA(insert OID = 3298 ( pg_readlink		PGNSP PGUID 12 1 0 0 0 f f f f t f v 1 0 25 "25" _null_ _null_ _null_ _null_ _null_ pg_readlink_1arg _null_ _null_ _null_ ));
+DESCR("read value of a symbolic link");
+DATA(insert OID = 3299 ( pg_readlink		PGNSP PGUID 12 1 0 0 0 f f f f t f v 2 0 25 "25 16" _null_ _null_ _null_ _null_ _null_ pg_readlink _null_ _null_ _null_ ));
+DESCR("read value of a symbolic link");
 DATA(insert OID = 2626 ( pg_sleep			PGNSP PGUID 12 1 0 0 0 f f f f t f v 1 0 2278 "701" _null_ _null_ _null_ _null_ _null_ pg_sleep _null_ _null_ _null_ ));
 DESCR("sleep for the specified time in seconds");
 DATA(insert OID = 3935 ( pg_sleep_for			PGNSP PGUID 14 1 0 0 0 f f f f t f v 1 0 2278 "1186" _null_ _null_ _null_ _null_ _null_ "select pg_catalog.pg_sleep(extract(epoch from pg_catalog.clock_timestamp() operator(pg_catalog.+) $1) operator(pg_catalog.-) extract(epoch from pg_catalog.clock_timestamp()))" _null_ _null_ _null_ ));
diff --git a/src/include/utils/builtins.h b/src/include/utils/builtins.h
index 9855672..615e5ab 100644
--- a/src/include/utils/builtins.h
+++ b/src/include/utils/builtins.h
@@ -479,6 +479,8 @@ extern Datum pg_read_binary_file_off_len(PG_FUNCTION_ARGS);
 extern Datum pg_read_binary_file_all(PG_FUNCTION_ARGS);
 extern Datum pg_ls_dir(PG_FUNCTION_ARGS);
 extern Datum pg_ls_dir_1arg(PG_FUNCTION_ARGS);
+extern Datum pg_readlink(PG_FUNCTION_ARGS);
+extern Datum pg_readlink_1arg(PG_FUNCTION_ARGS);
 
 /* misc.c */
 extern Datum current_database(PG_FUNCTION_ARGS);
-- 
2.4.5

From bdf72b13775b7fa71d24a92c71fc0c4002109e01 Mon Sep 17 00:00:00 2001
From: Michael Paquier <michael@otacoo.com>
Date: Mon, 29 Jun 2015 15:07:24 +0900
Subject: [PATCH 4/5] Extend pg_tablespace_location with option missing_ok

This is useful for code paths that prefer receive an empty response
instead of an ERROR if tablespace specified does not exist.
---
 doc/src/sgml/func.sgml        |  9 +++++++--
 src/backend/utils/adt/misc.c  | 30 ++++++++++++++++++++++++++----
 src/include/catalog/pg_proc.h |  2 ++
 src/include/utils/builtins.h  |  1 +
 4 files changed, 36 insertions(+), 6 deletions(-)

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 80a4f26..0257df6 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -15850,9 +15850,14 @@ SELECT pg_type_is_visible('myschema.widget'::regtype);
        <entry>get the set of database OIDs that have objects in the tablespace</entry>
       </row>
       <row>
-       <entry><literal><function>pg_tablespace_location(<parameter>tablespace_oid</parameter>)</function></literal></entry>
+       <entry><literal><function>pg_tablespace_location(<parameter>tablespace_oid</parameter> [, <parameter>missing_ok</> <type>boolean</type>])</function></literal></entry>
        <entry><type>text</type></entry>
-       <entry>get the path in the file system that this tablespace is located in</entry>
+       <entry>
+        Get the path in the file system that this tablespace is located in.
+        If <parameter>missing_ok</> is <literal>true</>, the function returns
+        NULL when the tablespace does not exist. if <literal>false</>, an
+        error is raised. The default is <literal>false</>.
+       </entry>
       </row>
       <row>
        <entry><literal><function>pg_typeof(<parameter>any</parameter>)</function></literal></entry>
diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c
index c0495d9..f5f61c5 100644
--- a/src/backend/utils/adt/misc.c
+++ b/src/backend/utils/adt/misc.c
@@ -347,6 +347,10 @@ pg_tablespace_location(PG_FUNCTION_ARGS)
 	char		sourcepath[MAXPGPATH];
 	char		targetpath[MAXPGPATH];
 	int			rllen;
+	bool		missing_ok = false;
+
+	if (PG_NARGS() == 2)
+		missing_ok = PG_GETARG_BOOL(1);
 
 	/*
 	 * It's useful to apply this function to pg_class.reltablespace, wherein
@@ -373,10 +377,15 @@ pg_tablespace_location(PG_FUNCTION_ARGS)
 
 	rllen = readlink(sourcepath, targetpath, sizeof(targetpath));
 	if (rllen < 0)
-		ereport(ERROR,
-				(errcode_for_file_access(),
-				 errmsg("could not read symbolic link \"%s\": %m",
-						sourcepath)));
+	{
+		if (missing_ok && errno == ENOENT)
+			PG_RETURN_NULL();
+		else
+			ereport(ERROR,
+					(errcode_for_file_access(),
+					 errmsg("could not read symbolic link \"%s\": %m",
+							sourcepath)));
+	}
 	if (rllen >= sizeof(targetpath))
 		ereport(ERROR,
 				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
@@ -394,6 +403,19 @@ pg_tablespace_location(PG_FUNCTION_ARGS)
 }
 
 /*
+ * pg_tablespace_location (1 argument version)
+ *
+ * note: this wrapper is necessary to pass the sanity check in opr_sanity,
+ * which checks that all built-in functions that share the implementing C
+ * function take the same number of arguments.
+ */
+Datum
+pg_tablespace_location_1arg(PG_FUNCTION_ARGS)
+{
+	return pg_tablespace_location(fcinfo);
+}
+
+/*
  * pg_sleep - delay for N seconds
  */
 Datum
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index f9c6176..6ccbf9b 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -2922,6 +2922,8 @@ DESCR("current trigger depth");
 
 DATA(insert OID = 3778 ( pg_tablespace_location PGNSP PGUID 12 1 0 0 0 f f f f t f s 1 0 25 "26" _null_ _null_ _null_ _null_ _null_ pg_tablespace_location _null_ _null_ _null_ ));
 DESCR("tablespace location");
+DATA(insert OID = 3579 ( pg_tablespace_location PGNSP PGUID 12 1 0 0 0 f f f f t f s 2 0 25 "26 16" _null_ _null_ _null_ _null_ _null_ pg_tablespace_location_1arg _null_ _null_ _null_ ));
+DESCR("tablespace location");
 
 DATA(insert OID = 1946 (  encode						PGNSP PGUID 12 1 0 0 0 f f f f t f i 2 0 25 "17 25" _null_ _null_ _null_ _null_ _null_ binary_encode _null_ _null_ _null_ ));
 DESCR("convert bytea value into some ascii-only text string");
diff --git a/src/include/utils/builtins.h b/src/include/utils/builtins.h
index 615e5ab..150afb6 100644
--- a/src/include/utils/builtins.h
+++ b/src/include/utils/builtins.h
@@ -490,6 +490,7 @@ extern Datum pg_terminate_backend(PG_FUNCTION_ARGS);
 extern Datum pg_reload_conf(PG_FUNCTION_ARGS);
 extern Datum pg_tablespace_databases(PG_FUNCTION_ARGS);
 extern Datum pg_tablespace_location(PG_FUNCTION_ARGS);
+extern Datum pg_tablespace_location_1arg(PG_FUNCTION_ARGS);
 extern Datum pg_rotate_logfile(PG_FUNCTION_ARGS);
 extern Datum pg_sleep(PG_FUNCTION_ARGS);
 extern Datum pg_get_keywords(PG_FUNCTION_ARGS);
-- 
2.4.5

From f44c286ec129deaf120986a5025996001cfd8ffe Mon Sep 17 00:00:00 2001
From: Michael Paquier <michael@otacoo.com>
Date: Mon, 29 Jun 2015 15:09:34 +0900
Subject: [PATCH 5/5] Fix symlink usage in pg_rewind

Make use of pg_readlink to determine where a symlink in a source PGDATA
streamed is from. Also remove restrictions related to symlink comparisons
on source and target instances, those need to be only limited to
tablespaces.
---
 src/bin/pg_rewind/file_ops.c    |  2 ++
 src/bin/pg_rewind/filemap.c     | 11 +++--------
 src/bin/pg_rewind/filemap.h     |  1 +
 src/bin/pg_rewind/libpq_fetch.c | 32 ++++++++++++++++----------------
 4 files changed, 22 insertions(+), 24 deletions(-)

diff --git a/src/bin/pg_rewind/file_ops.c b/src/bin/pg_rewind/file_ops.c
index c2d8aa1..29ddb1d 100644
--- a/src/bin/pg_rewind/file_ops.c
+++ b/src/bin/pg_rewind/file_ops.c
@@ -139,6 +139,7 @@ remove_target(file_entry_t *entry)
 			remove_target_file(entry->path);
 			break;
 
+		case FILE_TYPE_TABLESPACE:
 		case FILE_TYPE_SYMLINK:
 			remove_target_symlink(entry->path);
 			break;
@@ -156,6 +157,7 @@ create_target(file_entry_t *entry)
 			create_target_dir(entry->path);
 			break;
 
+		case FILE_TYPE_TABLESPACE:
 		case FILE_TYPE_SYMLINK:
 			create_target_symlink(entry->path, entry->link_target);
 			break;
diff --git a/src/bin/pg_rewind/filemap.c b/src/bin/pg_rewind/filemap.c
index 05eff68..6ef2342 100644
--- a/src/bin/pg_rewind/filemap.c
+++ b/src/bin/pg_rewind/filemap.c
@@ -112,12 +112,6 @@ process_source_file(const char *path, file_type_t type, size_t newsize,
 	switch (type)
 	{
 		case FILE_TYPE_DIRECTORY:
-			if (exists && !S_ISDIR(statbuf.st_mode))
-			{
-				/* it's a directory in source, but not in target. Strange.. */
-				pg_fatal("\"%s\" is not a directory\n", localpath);
-			}
-
 			if (!exists)
 				action = FILE_ACTION_CREATE;
 			else
@@ -125,7 +119,7 @@ process_source_file(const char *path, file_type_t type, size_t newsize,
 			oldsize = 0;
 			break;
 
-		case FILE_TYPE_SYMLINK:
+		case FILE_TYPE_TABLESPACE:
 			if (exists &&
 #ifndef WIN32
 				!S_ISLNK(statbuf.st_mode)
@@ -140,7 +134,8 @@ process_source_file(const char *path, file_type_t type, size_t newsize,
 				 */
 				pg_fatal("\"%s\" is not a symbolic link\n", localpath);
 			}
-
+			/* fallback to default */
+		case FILE_TYPE_SYMLINK:
 			if (!exists)
 				action = FILE_ACTION_CREATE;
 			else
diff --git a/src/bin/pg_rewind/filemap.h b/src/bin/pg_rewind/filemap.h
index 9943ec5..35540d6 100644
--- a/src/bin/pg_rewind/filemap.h
+++ b/src/bin/pg_rewind/filemap.h
@@ -36,6 +36,7 @@ typedef enum
 {
 	FILE_TYPE_REGULAR,
 	FILE_TYPE_DIRECTORY,
+	FILE_TYPE_TABLESPACE,
 	FILE_TYPE_SYMLINK
 } file_type_t;
 
diff --git a/src/bin/pg_rewind/libpq_fetch.c b/src/bin/pg_rewind/libpq_fetch.c
index 05aa133..d77c931 100644
--- a/src/bin/pg_rewind/libpq_fetch.c
+++ b/src/bin/pg_rewind/libpq_fetch.c
@@ -140,30 +140,26 @@ libpqProcessFileList(void)
 	 * Create a recursive directory listing of the whole data directory.
 	 *
 	 * The WITH RECURSIVE part does most of the work. The second part gets the
-	 * targets of the symlinks in pg_tblspc directory.
-	 *
-	 * XXX: There is no backend function to get a symbolic link's target in
-	 * general, so if the admin has put any custom symbolic links in the data
-	 * directory, they won't be copied correctly.
+	 * targets of the symlinks in the data directory.
 	 */
 	sql =
-		"WITH RECURSIVE files (path, filename, size, isdir) AS (\n"
-		"  SELECT '' AS path, filename, size, isdir FROM\n"
+		"WITH RECURSIVE files (path, filename, size, isdir, islink) AS (\n"
+		"  SELECT '' AS path, filename, size, isdir, islink FROM\n"
 		"  (SELECT pg_ls_dir('.', true, false) AS filename) AS fn,\n"
 		"        pg_stat_file(fn.filename, true) AS this\n"
 		"  UNION ALL\n"
 		"  SELECT parent.path || parent.filename || '/' AS path,\n"
-		"         fn, this.size, this.isdir\n"
+		"         fn, this.size, this.isdir, this.islink\n"
 		"  FROM files AS parent,\n"
 		"       pg_ls_dir(parent.path || parent.filename, true, false) AS fn,\n"
 		"       pg_stat_file(parent.path || parent.filename || '/' || fn, true) AS this\n"
 		"       WHERE parent.isdir = 't'\n"
 		")\n"
-		"SELECT path || filename, size, isdir,\n"
-		"       pg_tablespace_location(pg_tablespace.oid) AS link_target\n"
-		"FROM files\n"
-		"LEFT OUTER JOIN pg_tablespace ON files.path = 'pg_tblspc/'\n"
-		"                             AND oid::text = files.filename\n";
+		"SELECT path || filename, size, isdir, islink,\n"
+		"       path = 'pg_tblspc/' AS istblspc,\n"
+		"       CASE WHEN islink THEN pg_readlink(path || filename)\n"
+		"            ELSE NULL END AS link_target\n"
+		"FROM files\n";
 	res = PQexec(conn, sql);
 
 	if (PQresultStatus(res) != PGRES_TUPLES_OK)
@@ -171,7 +167,7 @@ libpqProcessFileList(void)
 				 PQresultErrorMessage(res));
 
 	/* sanity check the result set */
-	if (PQnfields(res) != 4)
+	if (PQnfields(res) != 6)
 		pg_fatal("unexpected result set while fetching file list\n");
 
 	/* Read result to local variables */
@@ -180,7 +176,9 @@ libpqProcessFileList(void)
 		char	   *path = PQgetvalue(res, i, 0);
 		int			filesize = atoi(PQgetvalue(res, i, 1));
 		bool		isdir = (strcmp(PQgetvalue(res, i, 2), "t") == 0);
-		char	   *link_target = PQgetvalue(res, i, 3);
+		bool		islink = (strcmp(PQgetvalue(res, i, 3), "t") == 0);
+		bool		istblspc = (strcmp(PQgetvalue(res, i, 4), "t") == 0);
+		char	   *link_target = PQgetvalue(res, i, 5);
 		file_type_t type;
 
 		if (PQgetisnull(res, 0, 1))
@@ -192,7 +190,9 @@ libpqProcessFileList(void)
 			continue;
 		}
 
-		if (link_target[0])
+		if (istblspc)
+			type = FILE_TYPE_TABLESPACE;
+		else if (islink)
 			type = FILE_TYPE_SYMLINK;
 		else if (isdir)
 			type = FILE_TYPE_DIRECTORY;
-- 
2.4.5

diff --git a/doc/src/sgml/ref/pg_rewind.sgml b/doc/src/sgml/ref/pg_rewind.sgml
index 32dc83f..92325f3 100644
--- a/doc/src/sgml/ref/pg_rewind.sgml
+++ b/doc/src/sgml/ref/pg_rewind.sgml
@@ -234,4 +234,15 @@ PostgreSQL documentation
   </refsect2>
  </refsect1>
 
+ <refsect1>
+  <title>Notes</title>
+
+  <para>
+   Read-only files cannot be included in the data directory of target
+   instance before starting <application>pg_rewind</>. For example, soft
+   links to read-only files should be temporarily removed from the data
+   directory and added back after the process.
+  </para>
+ </refsect1>
+
 </refentry>

diff --git a/doc/src/sgml/ref/pg_rewind.sgml b/doc/src/sgml/ref/pg_rewind.sgml
index 32dc83f..bb1d640 100644
--- a/doc/src/sgml/ref/pg_rewind.sgml
+++ b/doc/src/sgml/ref/pg_rewind.sgml
@@ -49,12 +49,13 @@ PostgreSQL documentation
 
   <para>
    The result is equivalent to replacing the target data directory with the
-   source one. All files are copied, including configuration files. The
-   advantage of <application>pg_rewind</> over taking a new base backup, or
-   tools like <application>rsync</>, is that <application>pg_rewind</> does
-   not require reading through all unchanged files in the cluster. That makes
-   it a lot faster when the database is large and only a small portion of it
-   differs between the clusters.
+   source one. All files in the data directory are copied, including
+   configuration files, but excluding the WAL log directory,
+   <filename>pg_xlog</>. The advantage of <application>pg_rewind</> over
+   taking a new base backup, or tools like <application>rsync</>, is that
+   <application>pg_rewind</> does not require reading through all unchanged
+   files in the cluster. That makes it a lot faster when the database is
+   large and only a small portion of it differs between the clusters.
   </para>
 
   <para>
@@ -74,12 +75,12 @@ PostgreSQL documentation
    When the target server is started up for the first time after running
    <application>pg_rewind</>, it will go into recovery mode and replay all
    WAL generated in the source server after the point of divergence.
-   If some of the WAL was no longer available in the source server when
-   <application>pg_rewind</> was run, and therefore could not be copied by
-   <application>pg_rewind</> session, it needs to be made available when the
-   target server is started up. That can be done by creating a
-   <filename>recovery.conf</> file in the target data directory with a
-   suitable <varname>restore_command</>.
+   Like after restoring from a base backup using continous archiving,
+   the source server's WAL must be made available to the rewound server.
+   This can be done by creating a <filename>recovery.conf</> file in the
+   target data directory with a suitable <varname>restore_command</> or
+   <varname>primary_conninfo</> line, or by copying the required WAL files
+   manually into <filename>pg_xlog</> in the target data directory.
   </para>
  </refsect1>
 
diff --git a/src/bin/pg_rewind/RewindTest.pm b/src/bin/pg_rewind/RewindTest.pm
index 5219ec9..82e3f4c 100644
--- a/src/bin/pg_rewind/RewindTest.pm
+++ b/src/bin/pg_rewind/RewindTest.pm
@@ -284,14 +284,12 @@ sub run_pg_rewind
 
 	# Keep a temporary postgresql.conf for master node or it would be
 	# overwritten during the rewind.
-	copy(
-		"$test_master_datadir/postgresql.conf",
-		"$testroot/master-postgresql.conf.tmp");
+	copy("$test_master_datadir/postgresql.conf",
+		 "$testroot/master-postgresql.conf.tmp");
 
 	# Now run pg_rewind
 	if ($test_mode eq "local")
 	{
-
 		# Do rewind using a local pgdata as source
 		# Stop the master and be ready to perform the rewind
 		system_or_bail(
@@ -306,10 +304,22 @@ sub run_pg_rewind
 			$log_path,
 			'2>&1');
 		ok($result, 'pg_rewind local');
+
+		# Copy WAL files from the source server so that recovery will find
+		# them. (In remote mode, the source server is still running, and the
+		# rewound server will use streaming replication to connect to the
+		# source server and fetch the WAL from there.)
+		opendir(DIR,"$test_standby_datadir/pg_xlog") or die "Cannot open $test_standby_datadir/pg_xlo\n";
+		my @xlogfiles = readdir(DIR);
+		closedir(DIR);
+
+		foreach my $xlogfile (@xlogfiles) {
+			copy("$test_standby_datadir/pg_xlog/$xlogfile",
+				 "$test_master_datadir/pg_xlog/");
+		}
 	}
 	elsif ($test_mode eq "remote")
 	{
-
 		# Do rewind using a remote connection as source
 		my $result = run(
 			[   'pg_rewind',
diff --git a/src/bin/pg_rewind/copy_fetch.c b/src/bin/pg_rewind/copy_fetch.c
index 224fad1..f437391 100644
--- a/src/bin/pg_rewind/copy_fetch.c
+++ b/src/bin/pg_rewind/copy_fetch.c
@@ -74,6 +74,9 @@ recurse_dir(const char *datadir, const char *parentpath,
 			strcmp(xlde->d_name, "..") == 0)
 			continue;
 
+		if (parentpath == NULL && strcmp(xlde->d_name, "pg_xlog") == 0)
+			continue;
+
 		snprintf(fullpath, MAXPGPATH, "%s/%s", fullparentpath, xlde->d_name);
 
 		if (lstat(fullpath, &fst) < 0)
diff --git a/src/bin/pg_rewind/libpq_fetch.c b/src/bin/pg_rewind/libpq_fetch.c
index 05aa133..2f411e3 100644
--- a/src/bin/pg_rewind/libpq_fetch.c
+++ b/src/bin/pg_rewind/libpq_fetch.c
@@ -151,6 +151,7 @@ libpqProcessFileList(void)
 		"  SELECT '' AS path, filename, size, isdir FROM\n"
 		"  (SELECT pg_ls_dir('.', true, false) AS filename) AS fn,\n"
 		"        pg_stat_file(fn.filename, true) AS this\n"
+		"   WHERE filename <> 'pg_xlog'"
 		"  UNION ALL\n"
 		"  SELECT parent.path || parent.filename || '/' AS path,\n"
 		"         fn, this.size, this.isdir\n"

diff --git a/doc/src/sgml/ref/pg_rewind.sgml b/doc/src/sgml/ref/pg_rewind.sgml
index 32dc83f..bb1d640 100644
--- a/doc/src/sgml/ref/pg_rewind.sgml
+++ b/doc/src/sgml/ref/pg_rewind.sgml
@@ -49,12 +49,13 @@ PostgreSQL documentation
 
   <para>
    The result is equivalent to replacing the target data directory with the
-   source one. All files are copied, including configuration files. The
-   advantage of <application>pg_rewind</> over taking a new base backup, or
-   tools like <application>rsync</>, is that <application>pg_rewind</> does
-   not require reading through all unchanged files in the cluster. That makes
-   it a lot faster when the database is large and only a small portion of it
-   differs between the clusters.
+   source one. All files in the data directory are copied, including
+   configuration files, but excluding the WAL log directory,
+   <filename>pg_xlog</>. The advantage of <application>pg_rewind</> over
+   taking a new base backup, or tools like <application>rsync</>, is that
+   <application>pg_rewind</> does not require reading through all unchanged
+   files in the cluster. That makes it a lot faster when the database is
+   large and only a small portion of it differs between the clusters.
   </para>
 
   <para>
@@ -74,12 +75,12 @@ PostgreSQL documentation
    When the target server is started up for the first time after running
    <application>pg_rewind</>, it will go into recovery mode and replay all
    WAL generated in the source server after the point of divergence.
-   If some of the WAL was no longer available in the source server when
-   <application>pg_rewind</> was run, and therefore could not be copied by
-   <application>pg_rewind</> session, it needs to be made available when the
-   target server is started up. That can be done by creating a
-   <filename>recovery.conf</> file in the target data directory with a
-   suitable <varname>restore_command</>.
+   Like after restoring from a base backup using continous archiving,
+   the source server's WAL must be made available to the rewound server.
+   This can be done by creating a <filename>recovery.conf</> file in the
+   target data directory with a suitable <varname>restore_command</> or
+   <varname>primary_conninfo</> line, or by copying the required WAL files
+   manually into <filename>pg_xlog</> in the target data directory.
   </para>
  </refsect1>
 
diff --git a/src/bin/pg_rewind/RewindTest.pm b/src/bin/pg_rewind/RewindTest.pm
index db5e90b..4d0fe6d 100644
--- a/src/bin/pg_rewind/RewindTest.pm
+++ b/src/bin/pg_rewind/RewindTest.pm
@@ -290,6 +290,21 @@ sub run_pg_rewind
 					"--source-pgdata=$test_standby_datadir",
 					"--target-pgdata=$test_master_datadir"],
 				   'pg_rewind local');
+
+		# Copy WAL files from the source server so that recovery will find
+		# them. (In remote mode, the source server is still running, and the
+		# rewound server will use streaming replication to connect to the
+		# source server and fetch the WAL from there.)
+		opendir(DIR,"$test_standby_datadir/pg_xlog") or
+			die "Cannot open $test_standby_datadir/pg_xlog\n";
+		my @xlogfiles = readdir(DIR);
+		closedir(DIR);
+
+		foreach my $xlogfile (@xlogfiles)
+		{
+			copy("$test_standby_datadir/pg_xlog/$xlogfile",
+				 "$test_master_datadir/pg_xlog/");
+		}
 	}
 	elsif ($test_mode eq "remote")
 	{
diff --git a/src/bin/pg_rewind/copy_fetch.c b/src/bin/pg_rewind/copy_fetch.c
index 224fad1..f437391 100644
--- a/src/bin/pg_rewind/copy_fetch.c
+++ b/src/bin/pg_rewind/copy_fetch.c
@@ -74,6 +74,9 @@ recurse_dir(const char *datadir, const char *parentpath,
 			strcmp(xlde->d_name, "..") == 0)
 			continue;
 
+		if (parentpath == NULL && strcmp(xlde->d_name, "pg_xlog") == 0)
+			continue;
+
 		snprintf(fullpath, MAXPGPATH, "%s/%s", fullparentpath, xlde->d_name);
 
 		if (lstat(fullpath, &fst) < 0)
diff --git a/src/bin/pg_rewind/libpq_fetch.c b/src/bin/pg_rewind/libpq_fetch.c
index 1979fbc..bf99e9a 100644
--- a/src/bin/pg_rewind/libpq_fetch.c
+++ b/src/bin/pg_rewind/libpq_fetch.c
@@ -154,6 +154,7 @@ libpqProcessFileList(void)
 		"  SELECT '' AS path, filename, size, isdir FROM\n"
 		"  (SELECT pg_ls_dir('.', true, false) AS filename) AS fn,\n"
 		"        pg_stat_file(fn.filename, true) AS this\n"
+		"   WHERE filename <> 'pg_xlog'"
 		"  UNION ALL\n"
 		"  SELECT parent.path || parent.filename || '/' AS path,\n"
 		"         fn, this.size, this.isdir\n"