Arrange for the postmaster (and standalone backends, initdb, etc) to

chdir into PGDATA and subsequently use relative paths instead of absolute
paths to access all files under PGDATA.  This seems to give a small
performance improvement, and it should make the system more robust
against naive DBAs doing things like moving a database directory that
has a live postmaster in it.  Per recent discussion.

1 files changed, 22 insertions, 25 deletions

diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index d14f6db1630..2de55276483 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -37,7 +37,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/postmaster/postmaster.c,v 1.457 2005/06/30 10:02:22 petere Exp $
+ *	  $PostgreSQL: pgsql/src/backend/postmaster/postmaster.c,v 1.458 2005/07/04 04:51:47 tgl Exp $
  *
  * NOTES
  *
@@ -585,6 +585,15 @@ PostmasterMain(int argc, char *argv[])
 		ExitPostmaster(1);
 	}
 
+#ifdef EXEC_BACKEND
+	/* Locate executable backend before we change working directory */
+	if (find_other_exec(argv[0], "postgres", PG_VERSIONSTR,
+						postgres_exec_path) < 0)
+		ereport(FATAL,
+			 (errmsg("%s: could not locate matching postgres executable",
+					 progname)));
+#endif
+
 	/*
 	 * Locate the proper configuration files and data directory, and
 	 * read postgresql.conf for the first time.
@@ -595,6 +604,9 @@ PostmasterMain(int argc, char *argv[])
 	/* Verify that DataDir looks reasonable */
 	checkDataDir();
 
+	/* And switch working directory into it */
+	ChangeToDataDir();
+
 	/*
 	 * Check for invalid combinations of GUC settings.
 	 */
@@ -650,14 +662,6 @@ PostmasterMain(int argc, char *argv[])
 		 (errmsg_internal("-----------------------------------------")));
 	}
 
-#ifdef EXEC_BACKEND
-	if (find_other_exec(argv[0], "postgres", PG_VERSIONSTR,
-						postgres_exec_path) < 0)
-		ereport(FATAL,
-			 (errmsg("%s: could not locate matching postgres executable",
-					 progname)));
-#endif
-
 	/*
 	 * Initialize SSL library, if specified.
 	 */
@@ -691,7 +695,7 @@ PostmasterMain(int argc, char *argv[])
 	 * :-(). For the same reason, it's best to grab the TCP socket(s)
 	 * before the Unix socket.
 	 */
-	CreateDataDirLockFile(DataDir, true);
+	CreateDataDirLockFile(true);
 
 	/*
 	 * Remove old temporary files.	At this point there can be no other
@@ -786,8 +790,6 @@ PostmasterMain(int argc, char *argv[])
 		ereport(FATAL,
 				(errmsg("no socket created for listening")));
 
-	XLOGPathInit();
-
 	/*
 	 * Set up shared memory and semaphores.
 	 */
@@ -2866,20 +2868,16 @@ internal_forkexec(int argc, char *argv[], Port *port)
 		return -1;				/* log made by save_backend_variables */
 
 	/* Calculate name for temp file */
-	Assert(DataDir);
-	snprintf(tmpfilename, MAXPGPATH, "%s/%s/%s.backend_var.%d.%lu",
-			 DataDir, PG_TEMP_FILES_DIR, PG_TEMP_FILE_PREFIX,
+	snprintf(tmpfilename, MAXPGPATH, "%s/%s.backend_var.%d.%lu",
+			 PG_TEMP_FILES_DIR, PG_TEMP_FILE_PREFIX,
 			 MyProcPid, ++tmpBackendFileNum);
 
 	/* Open file */
 	fp = AllocateFile(tmpfilename, PG_BINARY_W);
 	if (!fp)
 	{
-		/* As per OpenTemporaryFile... */
-		char		dirname[MAXPGPATH];
-
-		snprintf(dirname, MAXPGPATH, "%s/%s", DataDir, PG_TEMP_FILES_DIR);
-		mkdir(dirname, S_IRWXU);
+		/* As in OpenTemporaryFile, try to make the temp-file directory */
+		mkdir(PG_TEMP_FILES_DIR, S_IRWXU);
 
 		fp = AllocateFile(tmpfilename, PG_BINARY_W);
 		if (!fp)
@@ -3527,15 +3525,14 @@ StartChildProcess(int xlop)
 static bool
 CreateOptsFile(int argc, char *argv[], char *fullprogname)
 {
-	char		filename[MAXPGPATH];
 	FILE	   *fp;
 	int			i;
 
-	snprintf(filename, sizeof(filename), "%s/postmaster.opts", DataDir);
+#define OPTS_FILE	"postmaster.opts"
 
-	if ((fp = fopen(filename, "w")) == NULL)
+	if ((fp = fopen(OPTS_FILE, "w")) == NULL)
 	{
-		elog(LOG, "could not create file \"%s\": %m", filename);
+		elog(LOG, "could not create file \"%s\": %m", OPTS_FILE);
 		return false;
 	}
 
@@ -3546,7 +3543,7 @@ CreateOptsFile(int argc, char *argv[], char *fullprogname)
 
 	if (fclose(fp))
 	{
-		elog(LOG, "could not write file \"%s\": %m", filename);
+		elog(LOG, "could not write file \"%s\": %m", OPTS_FILE);
 		return false;
 	}