Code review for postmaster.pid contents changes.

Fix broken test for pre-existing postmaster, caused by wrong code for
appending lines to the lockfile; don't write a failed listen_address
setting into the lockfile; don't arbitrarily change the location of the
data directory in the lockfile compared to previous releases; provide more
consistent and useful definitions of the socket path and listen_address
entries; avoid assuming that pg_ctl has the same DEFAULT_PGSOCKET_DIR as
the postmaster; assorted code style improvements.

4 files changed, 67 insertions, 62 deletions

diff --git a/src/backend/port/ipc_test.c b/src/backend/port/ipc_test.c
index 2518007c4b6..b4bcf40a7ab 100644
--- a/src/backend/port/ipc_test.c
+++ b/src/backend/port/ipc_test.c
@@ -104,7 +104,7 @@ on_exit_reset(void)
 }
 
 void
-AddToLockFile(int target_line, const char *str)
+AddToDataDirLockFile(int target_line, const char *str)
 {
 }
 
@@ -135,7 +135,7 @@ errcode_for_file_access(void)
 
 bool
 errstart(int elevel, const char *filename, int lineno,
-		 const char *funcname)
+		 const char *funcname, const char *domain)
 {
 	return (elevel >= ERROR);
 }
diff --git a/src/backend/port/sysv_shmem.c b/src/backend/port/sysv_shmem.c
index 474c6142ebe..aece026ec64 100644
--- a/src/backend/port/sysv_shmem.c
+++ b/src/backend/port/sysv_shmem.c
@@ -199,15 +199,16 @@ InternalIpcMemoryCreate(IpcMemoryKey memKey, Size size)
 	on_shmem_exit(IpcMemoryDetach, PointerGetDatum(memAddress));
 
 	/*
-	 * Append record key and ID in lockfile for data directory. Format
-	 * to try to keep it the same length.
+	 * Store shmem key and ID in data directory lockfile.  Format to try to
+	 * keep it the same length always (trailing junk in the lockfile won't
+	 * hurt, but might confuse humans).
 	 */
 	{
-		char line[32];
+		char line[64];
 
-		sprintf(line, "%9lu %9lu\n", (unsigned long) memKey,
-									 (unsigned long) shmid);
-		AddToLockFile(LOCK_FILE_LINES, line);
+		sprintf(line, "%9lu %9lu",
+				(unsigned long) memKey, (unsigned long) shmid);
+		AddToDataDirLockFile(LOCK_FILE_LINE_SHMEM_KEY, line);
 	}
 
 	return memAddress;
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index d158ded390b..179048f32d1 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -482,9 +482,9 @@ PostmasterMain(int argc, char *argv[])
 	int			opt;
 	int			status;
 	char	   *userDoption = NULL;
+	bool		listen_addr_saved = false;
 	int			i;
-	bool		connection_line_output = false;
-	
+
 	MyProcPid = PostmasterPid = getpid();
 
 	MyStartTime = time(NULL);
@@ -861,24 +861,21 @@ PostmasterMain(int argc, char *argv[])
 										  UnixSocketDir,
 										  ListenSocket, MAXLISTEN);
 			else
-			{
 				status = StreamServerPort(AF_UNSPEC, curhost,
 										  (unsigned short) PostPortNumber,
 										  UnixSocketDir,
 										  ListenSocket, MAXLISTEN);
-				/* must supply a valid listen_address for PQping() */
-				if (!connection_line_output)
-				{
-					char line[MAXPGPATH + 2];
 
-					sprintf(line, "%s\n", curhost);
-					AddToLockFile(LOCK_FILE_LINES - 1, line);
-					connection_line_output = true;
-				}
-			}
-				
 			if (status == STATUS_OK)
+			{
 				success++;
+				/* record the first successful host addr in lockfile */
+				if (!listen_addr_saved)
+				{
+					AddToDataDirLockFile(LOCK_FILE_LINE_LISTEN_ADDR, curhost);
+					listen_addr_saved = true;
+				}
+			}
 			else
 				ereport(WARNING,
 						(errmsg("could not create listen socket for \"%s\"",
@@ -893,10 +890,6 @@ PostmasterMain(int argc, char *argv[])
 		pfree(rawstring);
 	}
 
-	/* Supply an empty listen_address line for PQping() */
-	if (!connection_line_output)
-		AddToLockFile(LOCK_FILE_LINES - 1, "\n");
-
 #ifdef USE_BONJOUR
 	/* Register for Bonjour only if we opened TCP socket(s) */
 	if (enable_bonjour && ListenSocket[0] != PGINVALID_SOCKET)
@@ -953,6 +946,14 @@ PostmasterMain(int argc, char *argv[])
 				(errmsg("no socket created for listening")));
 
 	/*
+	 * If no valid TCP ports, write an empty line for listen address,
+	 * indicating the Unix socket must be used.  Note that this line is not
+	 * added to the lock file until there is a socket backing it.
+	 */
+	if (!listen_addr_saved)
+		AddToDataDirLockFile(LOCK_FILE_LINE_LISTEN_ADDR, "");
+
+	/*
 	 * Set up shared memory and semaphores.
 	 */
 	reset_shared(PostPortNumber);
diff --git a/src/backend/utils/init/miscinit.c b/src/backend/utils/init/miscinit.c
index 4f708352daa..ef6422e75c3 100644
--- a/src/backend/utils/init/miscinit.c
+++ b/src/backend/utils/init/miscinit.c
@@ -46,20 +46,7 @@
 
 
 #define DIRECTORY_LOCK_FILE		"postmaster.pid"
-/*
- *	The lock file contents are:
- *
- * line #
- *		1	pid
- *		2	postmaster start time
- *		3	data directory
- *		4	port #
- *		5	user-specified socket directory
- *			(the lines below are added later)
- *		6	first valid listen_address
- *		7	shared memory key
- */
-	
+
 ProcessingMode Mode = InitProcessing;
 
 /* Note: we rely on this to initialize as zeroes */
@@ -244,7 +231,6 @@ static int	SecurityRestrictionContext = 0;
 static bool SetRoleIsActive = false;
 
 
-
 /*
  * GetUserId - get the current effective user ID.
  *
@@ -691,7 +677,7 @@ CreateLockFile(const char *filename, bool amPostmaster,
 			   bool isDDLock, const char *refName)
 {
 	int			fd;
-	char		buffer[MAXPGPATH * 3 + 256];
+	char		buffer[MAXPGPATH * 2 + 256];
 	int			ntries;
 	int			len;
 	int			encoded_pid;
@@ -852,26 +838,26 @@ CreateLockFile(const char *filename, bool amPostmaster,
 		 * looking to see if there is an associated shmem segment that is
 		 * still in use.
 		 *
-		 * Note: because postmaster.pid is written in two steps, we might not
-		 * find the shmem ID values in it; we can't treat that as an error.
+		 * Note: because postmaster.pid is written in multiple steps, we might
+		 * not find the shmem ID values in it; we can't treat that as an
+		 * error.
 		 */
 		if (isDDLock)
 		{
 			char	   *ptr = buffer;
-			unsigned long id1, id2;
-			int lineno;
+			unsigned long id1,
+						id2;
+			int			lineno;
 
-			for (lineno = 1; lineno <= LOCK_FILE_LINES - 1; lineno++)
+			for (lineno = 1; lineno < LOCK_FILE_LINE_SHMEM_KEY; lineno++)
 			{
 				if ((ptr = strchr(ptr, '\n')) == NULL)
-				{
-					elog(LOG, "bogus data in \"%s\"", DIRECTORY_LOCK_FILE);
 					break;
-				}
 				ptr++;
 			}
 
-			if (ptr && sscanf(ptr, "%lu %lu", &id1, &id2) == 2)
+			if (ptr != NULL &&
+				sscanf(ptr, "%lu %lu", &id1, &id2) == 2)
 			{
 				if (PGSharedMemoryIsInUse(id1, id2))
 					ereport(FATAL,
@@ -903,12 +889,23 @@ CreateLockFile(const char *filename, bool amPostmaster,
 	}
 
 	/*
-	 * Successfully created the file, now fill it.
+	 * Successfully created the file, now fill it.  See comment in miscadmin.h
+	 * about the contents.  Note that we write the same info into both datadir
+	 * and socket lockfiles; although more stuff may get added to the datadir
+	 * lockfile later.
 	 */
-	snprintf(buffer, sizeof(buffer), "%d\n%ld\n%s\n%d\n%s\n",
+	snprintf(buffer, sizeof(buffer), "%d\n%s\n%ld\n%d\n%s\n",
 			 amPostmaster ? (int) my_pid : -((int) my_pid),
-			 (long) MyStartTime, DataDir, PostPortNumber,
-			 UnixSocketDir);
+			 DataDir,
+			 (long) MyStartTime,
+			 PostPortNumber,
+#ifdef HAVE_UNIX_SOCKETS
+			 (*UnixSocketDir != '\0') ? UnixSocketDir : DEFAULT_PGSOCKET_DIR
+#else
+			 ""
+#endif
+			 );
+
 	errno = 0;
 	if (write(fd, buffer, strlen(buffer)) != strlen(buffer))
 	{
@@ -1019,17 +1016,20 @@ TouchSocketLockFile(void)
 
 
 /*
- * Add lines to the data directory lock file.  This erases all following
- * lines, but that is OK because lines are added in order.
+ * Add (or replace) a line in the data directory lock file.
+ * The given string should not include a trailing newline.
+ *
+ * Caution: this erases all following lines.  In current usage that is OK
+ * because lines are added in order.  We could improve it if needed.
  */
 void
-AddToLockFile(int target_line, const char *str)
+AddToDataDirLockFile(int target_line, const char *str)
 {
 	int			fd;
 	int			len;
 	int			lineno;
 	char	   *ptr;
-	char		buffer[MAXPGPATH * 3 + 256];
+	char		buffer[BLCKSZ];
 
 	fd = open(DIRECTORY_LOCK_FILE, O_RDWR | PG_BINARY, 0);
 	if (fd < 0)
@@ -1040,7 +1040,7 @@ AddToLockFile(int target_line, const char *str)
 						DIRECTORY_LOCK_FILE)));
 		return;
 	}
-	len = read(fd, buffer, sizeof(buffer) - 100);
+	len = read(fd, buffer, sizeof(buffer) - 1);
 	if (len < 0)
 	{
 		ereport(LOG,
@@ -1053,7 +1053,7 @@ AddToLockFile(int target_line, const char *str)
 	buffer[len] = '\0';
 
 	/*
-	 * Skip over first four lines (PID, pgdata, portnum, socketdir).
+	 * Skip over lines we are not supposed to rewrite.
 	 */
 	ptr = buffer;
 	for (lineno = 1; lineno < target_line; lineno++)
@@ -1066,8 +1066,11 @@ AddToLockFile(int target_line, const char *str)
 		}
 		ptr++;
 	}
-	
-	strlcat(buffer, str, sizeof(buffer));
+
+	/*
+	 * Write or rewrite the target line.
+	 */
+	snprintf(ptr, buffer + sizeof(buffer) - ptr, "%s\n", str);
 
 	/*
 	 * And rewrite the data.  Since we write in a single kernel call, this