Make pg_control file optional for restore.

stalkerg · stalkerg · commit 4f163d8b861a · 2016-03-02T20:50:33.000+03:00
diff --git a/backup.c b/backup.c
@@ -107,7 +107,7 @@ do_backup_database(parray *backup_list, pgBackupOption bkupopt)
 	 * obtained at output of pg_start_backup or pg_stop_backup does
 	 * not contain this information.
 	 */
-	current.tli = get_current_timeline();
+	current.tli = get_current_timeline(false);
 
 	/*
 	 * In differential backup mode, check if there is an already-validated
@@ -567,7 +567,7 @@ wait_for_archive(pgBackup *backup, const char *sql)
 	 * Enforce TLI obtention if backup is not present as this code
 	 * path can be taken as a callback at exit.
 	 */
-	tli = get_current_timeline();
+	tli = get_current_timeline(false);
 
 	/* Fill in fields if backup exists */
 	if (backup != NULL)
diff --git a/fetch.c b/fetch.c
@@ -33,7 +33,7 @@
  *
  */
 char *
-slurpFile(const char *datadir, const char *path, size_t *filesize)
+slurpFile(const char *datadir, const char *path, size_t *filesize, bool safe)
 {
 	int		 fd;
 	char	   *buffer;
@@ -43,20 +43,35 @@ slurpFile(const char *datadir, const char *path, size_t *filesize)
 	snprintf(fullpath, sizeof(fullpath), "%s/%s", datadir, path);
 
 	if ((fd = open(fullpath, O_RDONLY | PG_BINARY, 0)) == -1)
-		elog(ERROR, "could not open file \"%s\" for reading: %s",
-				fullpath, strerror(errno));
+	{
+		if (safe)
+			return NULL;
+		else
+			elog(ERROR, "could not open file \"%s\" for reading: %s",
+					fullpath, strerror(errno));
+	}
 
 	if (fstat(fd, &statbuf) < 0)
-		elog(ERROR, "could not open file \"%s\" for reading: %s",
-			 fullpath, strerror(errno));
+	{
+		if (safe)
+			return NULL;
+		else
+			elog(ERROR, "could not open file \"%s\" for reading: %s",
+				fullpath, strerror(errno));
+	}
 
 	len = statbuf.st_size;
 
 	buffer = pg_malloc(len + 1);
 
 	if (read(fd, buffer, len) != len)
-		elog(ERROR, "could not read file \"%s\": %s\n",
-			 fullpath, strerror(errno));
+	{
+		if (safe)
+			return NULL;
+		else
+			elog(ERROR, "could not read file \"%s\": %s\n",
+				fullpath, strerror(errno));
+	}
 
 	close(fd);
 
diff --git a/pg_arman.h b/pg_arman.h
@@ -231,7 +231,8 @@ extern void pgBackupDelete(int keep_generations, int keep_days);
 /* in fetch.c */
 extern char *slurpFile(const char *datadir,
 					   const char *path,
-					   size_t *filesize);
+					   size_t *filesize,
+					   bool safe);
 
 /* in validate.c */
 extern int do_validate(pgBackupRange *range);
@@ -291,7 +292,7 @@ extern void extractPageMap(const char *datadir, XLogRecPtr startpoint,
 						   TimeLineID tli, XLogRecPtr endpoint);
 
 /* in util.c */
-extern TimeLineID get_current_timeline(void);
+extern TimeLineID get_current_timeline(bool safe);
 extern void sanityChecks(void);
 extern void time2iso(char *buf, size_t len, time_t time);
 extern const char *status2str(BackupStatus status);
diff --git a/restore.c b/restore.c
@@ -98,7 +98,7 @@ do_restore(const char *target_time,
 	if (!backups)
 		elog(ERROR, "cannot process any more.");
 
-	cur_tli = get_current_timeline();
+	cur_tli = get_current_timeline(true);
 	backup_tli = get_fullbackup_timeline(backups, rt);
 
 	/* determine target timeline */
diff --git a/util.c b/util.c
@@ -60,7 +60,7 @@ sanityChecks(void)
 	size_t			size;
 
 	/* First fetch file... */
-	buffer = slurpFile(pgdata, "global/pg_control", &size);
+	buffer = slurpFile(pgdata, "global/pg_control", &size, false);
 	digestControlFile(&ControlFile, buffer, size);
 	pg_free(buffer);
 
@@ -80,14 +80,16 @@ sanityChecks(void)
  * used by a node.
  */
 TimeLineID
-get_current_timeline(void)
+get_current_timeline(bool safe)
 {
 	ControlFileData ControlFile;
 	char       *buffer;
 	size_t      size;
 
 	/* First fetch file... */
-	buffer = slurpFile(pgdata, "global/pg_control", &size);
+	buffer = slurpFile(pgdata, "global/pg_control", &size, safe);
+	if (buffer == NULL)
+		return 0;
 	digestControlFile(&ControlFile, buffer, size);
 	pg_free(buffer);
 
