archive.h File Reference

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Functions
int	RestoreArchivedFile (const char *path, const char *xlogfname, off_t expectedSize, const char *restoreCommand)

Function Documentation

RestoreArchivedFile()

int RestoreArchivedFile	(	const char *	path,
		const char *	xlogfname,
		off_t	expectedSize,
		const char *	restoreCommand
	)

Definition at line 39 of file archive.c.

{
    char        xlogpath[MAXPGPATH];
    char       *xlogRestoreCmd;
    int         rc;
    struct stat stat_buf;
 
    snprintf(xlogpath, MAXPGPATH, "%s/" XLOGDIR "/%s", path, xlogfname);
 
    xlogRestoreCmd = BuildRestoreCommand(restoreCommand, xlogpath,
                                         xlogfname, NULL);
    if (xlogRestoreCmd == NULL)
    {
        pg_log_fatal("cannot use restore_command with %%r placeholder");
        exit(1);
    }
 
    /*
     * Execute restore_command, which should copy the missing file from
     * archival storage.
     */
    rc = system(xlogRestoreCmd);
    pfree(xlogRestoreCmd);
 
    if (rc == 0)
    {
        /*
         * Command apparently succeeded, but let's make sure the file is
         * really there now and has the correct size.
         */
        if (stat(xlogpath, &stat_buf) == 0)
        {
            if (expectedSize > 0 && stat_buf.st_size != expectedSize)
            {
                pg_log_fatal("unexpected file size for \"%s\": %lld instead of %lld",
                             xlogfname, (long long int) stat_buf.st_size,
                             (long long int) expectedSize);
                exit(1);
            }
            else
            {
                int         xlogfd = open(xlogpath, O_RDONLY | PG_BINARY, 0);
 
                if (xlogfd < 0)
                {
                    pg_log_fatal("could not open file \"%s\" restored from archive: %m",
                                 xlogpath);
                    exit(1);
                }
                else
                    return xlogfd;
            }
        }
        else
        {
            if (errno != ENOENT)
            {
                pg_log_fatal("could not stat file \"%s\": %m",
                             xlogpath);
                exit(1);
            }
        }
    }
 
    /*
     * If the failure was due to a signal, then it would be misleading to
     * return with a failure at restoring the file.  So just bail out and
     * exit.  Hard shell errors such as "command not found" are treated as
     * fatal too.
     */
    if (wait_result_is_any_signal(rc, true))
    {
        pg_log_fatal("restore_command failed: %s",
                     wait_result_to_str(rc));
        exit(1);
    }
 
    /*
     * The file is not available, so just let the caller decide what to do
     * next.
     */
    pg_log_error("could not restore file \"%s\" from archive",
                 xlogfname);
    return -1;
}

References BuildRestoreCommand(), exit(), MAXPGPATH, pfree(), PG_BINARY, pg_log_error, pg_log_fatal, snprintf, stat::st_size, stat, wait_result_is_any_signal(), wait_result_to_str(), and XLOGDIR.