fmgr, C , and character arguments
Hello all,
I am having a bit of trouble getting my arguments formatted into a
command string for system(). Here is what I have so far for code.
#include <string.h>
#include <stdlib.h>
#include "postgres.h"
#include "fmgr.h"
PG_FUNCTION_INFO_V1(ssh_exec);
Datum
ssh_exec(PG_FUNCTION_ARGS)
{
char *uname = PG_GETARG_CHAR(0);
char *uid = PG_GETARG_CHAR(1);
char *gid = PG_GETARG_CHAR(2);
strncpy(sshcmd, "/usr/local/bin/plsshexec ", 255);
strncat(sshcmd, *uname, 255);
strncat(sshcmd, " ", 255);
strncat(sshcmd, *uid, 255);
strncat(sshcmd, " ", 255);
strncat(sshcmd, *gid, 255);
system(sshcmd);
return 0;
}
I am thinking that strncpy is not a bad idea after moving to the V-1
function manager interface. As I am sure you can see I am a C hack at best.
what is the best way to format the string and make this code work? memcpy?
Thanks for reading my post.
- Joel
On Tue, Mar 27, 2001 at 03:45:17PM -0700, Joel Dudley wrote:
Hello all,
I am having a bit of trouble getting my arguments formatted into a
command string for system(). Here is what I have so far for code.#include <string.h>
#include <stdlib.h>
#include "postgres.h"
#include "fmgr.h"PG_FUNCTION_INFO_V1(ssh_exec);
Try this:
Datum
ssh_exec(PG_FUNCTION_ARGS)
{
char *uname = PG_GETARG_CHAR(0);
char *uid = PG_GETARG_CHAR(1);
char *gid = PG_GETARG_CHAR(2);
strcpy(sshcmd, "/usr/local/bin/plsshexec ");
strncat(sshcmd, VARDATA(uname), VARSIZE(uname));
strcat(sshcmd, " ");
strncat(sshcmd, VARDATA(uid), VARSIZE(uid));
strcat(sshcmd, " ");
strncat(sshcmd, VARDATA(gid), VARSIZE(gid));
system(sshcmd);
return 0;
}
This may work, but is more to give you idea what PostgreSQL
vars are about. I would not use such code in my projects anyway :)
I suggest you study the code in src/backend/utils/adt/varchar.c
to see examples of char/text manipulation.
--
marko