From 2a3a35f2e80cb2badcb0efbce1bad2484e364b7b Mon Sep 17 00:00:00 2001 From: Mike Palmiotto Date: Fri, 27 Sep 2019 12:28:19 -0400 Subject: [PATCH 1/8] Add ForkProcType infrastructure --- src/backend/bootstrap/bootstrap.c | 1 + src/backend/main/main.c | 7 + src/backend/postmaster/postmaster.c | 197 ++++++++++++++++---------- src/backend/utils/init/globals.c | 3 +- src/backend/utils/init/postinit.c | 2 +- src/include/bootstrap/bootstrap.h | 2 +- src/include/postmaster/fork_process.h | 33 +++++ 7 files changed, 167 insertions(+), 78 deletions(-) diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c index 9238fbe98d..9f3dad1c6d 100644 --- a/src/backend/bootstrap/bootstrap.c +++ b/src/backend/bootstrap/bootstrap.c @@ -70,6 +70,7 @@ static void cleanup(void); */ AuxProcType MyAuxProcType = NotAnAuxProcess; /* declared in miscadmin.h */ +ForkProcType MyForkProcType = NoForkProcess; /* declared in fork_process.h */ Relation boot_reldesc; /* current relation descriptor */ diff --git a/src/backend/main/main.c b/src/backend/main/main.c index a9edbfd4a4..79942deb7d 100644 --- a/src/backend/main/main.c +++ b/src/backend/main/main.c @@ -199,7 +199,14 @@ main(int argc, char *argv[]) #endif if (argc > 1 && strcmp(argv[1], "--boot") == 0) + { + MemoryContext old_ctx; + + old_ctx = MemoryContextSwitchTo(TopMemoryContext); + AuxiliaryProcessMain(argc, argv); /* does not return */ + MemoryContextSwitchTo(old_ctx); + } else if (argc > 1 && strcmp(argv[1], "--describe-config") == 0) GucInfoMain(); /* does not return */ else if (argc > 1 && strcmp(argv[1], "--single") == 0) diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index eb9e0221f8..e0d11cc6ab 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -421,7 +421,7 @@ static int CountChildren(int target); static bool assign_backendlist_entry(RegisteredBgWorker *rw); static void maybe_start_bgworkers(void); static bool CreateOptsFile(int argc, char *argv[], char *fullprogname); -static pid_t StartChildProcess(AuxProcType type); +static pid_t StartChildProcess(ForkProcType type); static void StartAutovacuumWorker(void); static void MaybeStartWalReceiver(void); static void InitPostmasterDeathWatchHandle(void); @@ -456,7 +456,7 @@ typedef struct #endif /* WIN32 */ static pid_t backend_forkexec(Port *port); -static pid_t internal_forkexec(int argc, char *argv[], Port *port); +static pid_t internal_forkexec(int argc, char *argv[]); /* Type for a socket that can be inherited to a client process */ #ifdef WIN32 @@ -522,6 +522,7 @@ typedef struct char my_exec_path[MAXPGPATH]; char pkglib_path[MAXPGPATH]; char ExtraOptions[MAXPGPATH]; + ForkProcType proc_type; } BackendParameters; static void read_backend_variables(char *id, Port *port); @@ -538,11 +539,11 @@ static void ShmemBackendArrayAdd(Backend *bn); static void ShmemBackendArrayRemove(Backend *bn); #endif /* EXEC_BACKEND */ -#define StartupDataBase() StartChildProcess(StartupProcess) -#define StartBackgroundWriter() StartChildProcess(BgWriterProcess) -#define StartCheckpointer() StartChildProcess(CheckpointerProcess) -#define StartWalWriter() StartChildProcess(WalWriterProcess) -#define StartWalReceiver() StartChildProcess(WalReceiverProcess) +#define StartupDataBase() StartChildProcess(StartupFork) +#define StartBackgroundWriter() StartChildProcess(BgWriterFork) +#define StartCheckpointer() StartChildProcess(CheckpointerFork) +#define StartWalWriter() StartChildProcess(WalWriterFork) +#define StartWalReceiver() StartChildProcess(WalReceiverFork) /* Macros to check exit status of a child process */ #define EXIT_STATUS_0(st) ((st) == 0) @@ -560,6 +561,60 @@ int postmaster_alive_fds[2] = {-1, -1}; HANDLE PostmasterHandle; #endif +static Port *ConnProcPort = NULL; + +/* + * PrepAuxProcessFork + * + * Prepare a ForkProcType struct for the auxiliary process specified by + * AuxProcType. This does all prep related to av parameters and error messages. + */ +static void +PrepAuxProcessFork(ForkProcData *aux_fork) +{ + int ac = 0; + + /* + * Set up command-line arguments for subprocess + */ + aux_fork->av[ac++] = pstrdup("postgres"); + +#ifdef EXEC_BACKEND + aux_fork->av[ac++] = pstrdup("--forkboot"); + aux_fork->av[ac++] = NULL; /* filled in by postmaster_forkexec */ +#endif + + aux_fork->av[ac++] = psprintf("-x%d", MyForkProcType); + + aux_fork->av[ac] = NULL; + Assert(ac < lengthof(*aux_fork->av)); + + aux_fork->ac = ac; + switch (MyForkProcType) + { + case StartupProcess: + aux_fork->type_desc = pstrdup("startup"); + break; + case BgWriterProcess: + aux_fork->type_desc = pstrdup("background writer"); + break; + case CheckpointerProcess: + aux_fork->type_desc = pstrdup("checkpointer"); + break; + case WalWriterProcess: + aux_fork->type_desc = pstrdup("WAL writer"); + break; + case WalReceiverProcess: + aux_fork->type_desc = pstrdup("WAL receiver"); + break; + default: + aux_fork->type_desc = pstrdup("child"); + break; + } + + aux_fork->child_main = AuxiliaryProcessMain; +} + /* * Postmaster main entry point */ @@ -1710,19 +1765,17 @@ ServerLoop(void) break; if (FD_ISSET(ListenSocket[i], &rmask)) { - Port *port; - - port = ConnCreate(ListenSocket[i]); - if (port) + ConnProcPort = ConnCreate(ListenSocket[i]); + if (ConnProcPort) { - BackendStartup(port); + BackendStartup(ConnProcPort); /* * We no longer need the open socket or port structure * in this process */ - StreamClose(port->sock); - ConnFree(port); + StreamClose(ConnProcPort->sock); + ConnFree(ConnProcPort); } } } @@ -4477,11 +4530,11 @@ BackendRun(Port *port) pid_t postmaster_forkexec(int argc, char *argv[]) { - Port port; - /* This entry point passes dummy values for the Port variables */ - memset(&port, 0, sizeof(port)); - return internal_forkexec(argc, argv, &port); + if (!ConnProcPort) + ConnProcPort = palloc0(sizeof(*ConnProcPort)); + + return internal_forkexec(argc, argv); } /* @@ -4506,7 +4559,7 @@ backend_forkexec(Port *port) av[ac] = NULL; Assert(ac < lengthof(av)); - return internal_forkexec(ac, av, port); + return internal_forkexec(ac, av); } #ifndef WIN32 @@ -4518,7 +4571,7 @@ backend_forkexec(Port *port) * - fork():s, and then exec():s the child process */ static pid_t -internal_forkexec(int argc, char *argv[], Port *port) +internal_forkexec(int argc, char *argv[]) { static unsigned long tmpBackendFileNum = 0; pid_t pid; @@ -4526,7 +4579,7 @@ internal_forkexec(int argc, char *argv[], Port *port) BackendParameters param; FILE *fp; - if (!save_backend_variables(¶m, port)) + if (!save_backend_variables(¶m, ConnProcPort)) return -1; /* log made by save_backend_variables */ /* Calculate name for temp file */ @@ -4836,9 +4889,12 @@ SubPostmasterMain(int argc, char *argv[]) if (argc < 3) elog(FATAL, "invalid subpostmaster invocation"); + Assert(!ConnProcPort); + /* Read in the variables file */ memset(&port, 0, sizeof(Port)); read_backend_variables(argv[2], &port); + ConnProcPort = &port; /* Close the postmaster's sockets (as soon as we know them) */ ClosePostmasterPorts(strcmp(argv[1], "--forklog") == 0); @@ -5360,7 +5416,6 @@ CountChildren(int target) return cnt; } - /* * StartChildProcess -- start an auxiliary process for the postmaster * @@ -5371,36 +5426,50 @@ CountChildren(int target) * to start subprocess. */ static pid_t -StartChildProcess(AuxProcType type) +StartChildProcess(ForkProcType type) { pid_t pid; - char *av[10]; - int ac = 0; - char typebuf[32]; - - /* - * Set up command-line arguments for subprocess - */ - av[ac++] = "postgres"; + ForkProcData *fork_data; + MemoryContext old_ctx; + + /* Keep fork data after splitting from postmaster */ + old_ctx = MemoryContextSwitchTo(TopMemoryContext); + fork_data = (ForkProcData *) palloc0(sizeof(ForkProcData)); + fork_data->av = palloc0(sizeof(char *) * 10); + MyForkProcType = type; + + switch(type) + { + /* Auxiliary Processes */ + case CheckerFork: + case BootstrapFork: + case StartupFork: + case BgWriterFork: + case CheckpointerFork: + case WalWriterFork: + case WalReceiverFork: + PrepAuxProcessFork(fork_data); + break; -#ifdef EXEC_BACKEND - av[ac++] = "--forkboot"; - av[ac++] = NULL; /* filled in by postmaster_forkexec */ -#endif + default: + break; + } - snprintf(typebuf, sizeof(typebuf), "-x%d", type); - av[ac++] = typebuf; + MemoryContextSwitchTo(old_ctx); - av[ac] = NULL; - Assert(ac < lengthof(av)); + /* Bail out if pre-conditions are not met */ + if (fork_data == NULL) + return 0; #ifdef EXEC_BACKEND - pid = postmaster_forkexec(ac, av); -#else /* !EXEC_BACKEND */ + pid = postmaster_forkexec(fork_data->ac, fork_data->av); +#else pid = fork_process(); +#endif if (pid == 0) /* child */ { +#ifndef EXEC_BACKEND InitPostmasterChild(); /* Close the postmaster's sockets */ @@ -5410,52 +5479,30 @@ StartChildProcess(AuxProcType type) MemoryContextSwitchTo(TopMemoryContext); MemoryContextDelete(PostmasterContext); PostmasterContext = NULL; +#endif + /* Call the process's main subroutine */ + fork_data->child_main (fork_data->ac, fork_data->av); - AuxiliaryProcessMain(ac, av); +#ifndef EXEC_BACKEND ExitPostmaster(0); +#endif } -#endif /* EXEC_BACKEND */ - - if (pid < 0) + else if (pid < 0) { /* in parent, fork failed */ - int save_errno = errno; + int save_errno = errno; - errno = save_errno; - switch (type) - { - case StartupProcess: - ereport(LOG, - (errmsg("could not fork startup process: %m"))); - break; - case BgWriterProcess: - ereport(LOG, - (errmsg("could not fork background writer process: %m"))); - break; - case CheckpointerProcess: - ereport(LOG, - (errmsg("could not fork checkpointer process: %m"))); - break; - case WalWriterProcess: - ereport(LOG, - (errmsg("could not fork WAL writer process: %m"))); - break; - case WalReceiverProcess: - ereport(LOG, - (errmsg("could not fork WAL receiver process: %m"))); - break; - default: - ereport(LOG, - (errmsg("could not fork process: %m"))); - break; - } + errno = save_errno; + ereport(LOG, + (errmsg("could not fork %s process: %m", fork_data->type_desc))); /* * fork failure is fatal during startup, but there's no need to choke * immediately if starting other child types fails. */ - if (type == StartupProcess) + if (MyForkProcType == StartupFork) ExitPostmaster(1); + return 0; } diff --git a/src/backend/utils/init/globals.c b/src/backend/utils/init/globals.c index 3bf96de256..51657924f1 100644 --- a/src/backend/utils/init/globals.c +++ b/src/backend/utils/init/globals.c @@ -38,9 +38,10 @@ volatile uint32 QueryCancelHoldoffCount = 0; volatile uint32 CritSectionCount = 0; int MyProcPid; +int MyChildProcPid; pg_time_t MyStartTime; TimestampTz MyStartTimestamp; -struct Port *MyProcPort; +struct Port *MyProcPort = NULL; int32 MyCancelKey; int MyPMChildSlot; diff --git a/src/backend/utils/init/postinit.c b/src/backend/utils/init/postinit.c index 29c5ec7b58..c0840c33a7 100644 --- a/src/backend/utils/init/postinit.c +++ b/src/backend/utils/init/postinit.c @@ -1113,7 +1113,7 @@ process_startup_options(Port *port, bool am_superuser) av = (char **) palloc(maxac * sizeof(char *)); ac = 0; - av[ac++] = "postgres"; + av[ac++] = pstrdup("postgres"); pg_split_opts(av, &ac, port->cmdline_options); diff --git a/src/include/bootstrap/bootstrap.h b/src/include/bootstrap/bootstrap.h index 85705602cb..3c53454069 100644 --- a/src/include/bootstrap/bootstrap.h +++ b/src/include/bootstrap/bootstrap.h @@ -15,7 +15,7 @@ #define BOOTSTRAP_H #include "nodes/execnodes.h" - +#include "postmaster/fork_process.h" /* * MAXATTR is the maximum number of attributes in a relation supported diff --git a/src/include/postmaster/fork_process.h b/src/include/postmaster/fork_process.h index eb3c8ec974..d912229055 100644 --- a/src/include/postmaster/fork_process.h +++ b/src/include/postmaster/fork_process.h @@ -12,6 +12,39 @@ #ifndef FORK_PROCESS_H #define FORK_PROCESS_H +#include "postmaster.h" + +typedef enum +{ + NoForkProcess = -1, + CheckerFork = 0, + BootstrapFork, + StartupFork, + BgWriterFork, + CheckpointerFork, + WalWriterFork, + WalReceiverFork, /* end of Auxiliary Process Forks */ + + NUMFORKPROCTYPES /* Must be last! */ +} ForkProcType; + +extern ForkProcType MyForkProcType; + +struct ForkProcData; + +typedef void (*ChildProcessMain) (int argc, char *argv[]); + +typedef struct ForkProcData +{ + char **av; + int ac; + int save_errno; /* for failure */ + char *type_desc; + ChildProcessMain postmaster_main; + ChildProcessMain child_main; + ChildProcessMain fail_main; +} ForkProcData; + extern pid_t fork_process(void); #endif /* FORK_PROCESS_H */ -- 2.23.0