/*
* pclose() plus useful error reporting
*/
int
pclose_check(FILE *stream)
{
int exitstatus;
char *reason;
exitstatus = pclose(stream);
if (exitstatus == 0)
return 0; /* all is well */
if (exitstatus == -1)
{
/* pclose() itself failed, and hopefully set errno */
log_error(_("pclose failed: %s"), strerror(errno));
}
else
{
reason = wait_result_to_str(exitstatus);
log_error("%s", reason);
#ifdef FRONTEND
free(reason);
#else
pfree(reason);
#endif
}
return exitstatus;
}
/*
* Execute a \copy command (frontend copy). We have to open a file (or execute
* a command), then submit a COPY query to the backend and either feed it data
* from the file or route its response into the file.
*/
bool
do_copy(const char *args)
{
PQExpBufferData query;
FILE *copystream;
struct copy_options *options;
bool success;
/* parse options */
options = parse_slash_copy(args);
if (!options)
return false;
/* prepare to read or write the target file */
if (options->file && !options->program)
canonicalize_path(options->file);
if (options->from)
{
if (options->file)
{
if (options->program)
{
fflush(stdout);
fflush(stderr);
errno = 0;
copystream = popen(options->file, PG_BINARY_R);
}
else
copystream = fopen(options->file, PG_BINARY_R);
}
else if (!options->psql_inout)
copystream = pset.cur_cmd_source;
else
copystream = stdin;
}
else
{
if (options->file)
{
if (options->program)
{
fflush(stdout);
fflush(stderr);
errno = 0;
#ifndef WIN32
pqsignal(SIGPIPE, SIG_IGN);
#endif
copystream = popen(options->file, PG_BINARY_W);
}
else
copystream = fopen(options->file, PG_BINARY_W);
}
else if (!options->psql_inout)
copystream = pset.queryFout;
else
copystream = stdout;
}
if (!copystream)
{
if (options->program)
psql_error("could not execute command \"%s\": %s\n",
options->file, strerror(errno));
else
psql_error("%s: %s\n",
options->file, strerror(errno));
free_copy_options(options);
return false;
}
if (!options->program)
{
struct stat st;
int result;
/* make sure the specified file is not a directory */
if ((result = fstat(fileno(copystream), &st)) < 0)
psql_error("could not stat file \"%s\": %s\n",
options->file, strerror(errno));
if (result == 0 && S_ISDIR(st.st_mode))
psql_error("%s: cannot copy from/to a directory\n",
options->file);
if (result < 0 || S_ISDIR(st.st_mode))
{
fclose(copystream);
free_copy_options(options);
return false;
}
}
/* build the command we will send to the backend */
initPQExpBuffer(&query);
printfPQExpBuffer(&query, "COPY ");
appendPQExpBufferStr(&query, options->before_tofrom);
if (options->from)
appendPQExpBufferStr(&query, " FROM STDIN ");
else
appendPQExpBufferStr(&query, " TO STDOUT ");
if (options->after_tofrom)
appendPQExpBufferStr(&query, options->after_tofrom);
/* run it like a user command, but with copystream as data source/sink */
pset.copyStream = copystream;
success = SendQuery(query.data);
pset.copyStream = NULL;
termPQExpBuffer(&query);
if (options->file != NULL)
{
if (options->program)
{
int pclose_rc = pclose(copystream);
if (pclose_rc != 0)
{
if (pclose_rc < 0)
psql_error("could not close pipe to external command: %s\n",
strerror(errno));
else
{
char *reason = wait_result_to_str(pclose_rc);
psql_error("%s: %s\n", options->file,
reason ? reason : "");
if (reason)
free(reason);
}
success = false;
}
#ifndef WIN32
pqsignal(SIGPIPE, SIG_DFL);
#endif
}
else
{
if (fclose(copystream) != 0)
{
psql_error("%s: %s\n", options->file, strerror(errno));
success = false;
}
}
}
free_copy_options(options);
return success;
}
/*
* Attempt to retrieve the specified file from off-line archival storage.
* If successful, fill "path" with its complete path (note that this will be
* a temp file name that doesn't follow the normal naming convention), and
* return TRUE.
*
* If not successful, fill "path" with the name of the normal on-line file
* (which may or may not actually exist, but we'll try to use it), and return
* FALSE.
*
* For fixed-size files, the caller may pass the expected size as an
* additional crosscheck on successful recovery. If the file size is not
* known, set expectedSize = 0.
*
* When 'cleanupEnabled' is false, refrain from deleting any old WAL segments
* in the archive. This is used when fetching the initial checkpoint record,
* when we are not yet sure how far back we need the WAL.
*/
bool
RestoreArchivedFile(char *path, const char *xlogfname,
const char *recovername, off_t expectedSize,
bool cleanupEnabled)
{
char xlogpath[MAXPGPATH];
char xlogRestoreCmd[MAXPGPATH];
char lastRestartPointFname[MAXPGPATH];
char *dp;
char *endp;
const char *sp;
int rc;
bool signaled;
struct stat stat_buf;
XLogSegNo restartSegNo;
XLogRecPtr restartRedoPtr;
TimeLineID restartTli;
/* In standby mode, restore_command might not be supplied */
if (recoveryRestoreCommand == NULL)
goto not_available;
/*
* When doing archive recovery, we always prefer an archived log file even
* if a file of the same name exists in XLOGDIR. The reason is that the
* file in XLOGDIR could be an old, un-filled or partly-filled version
* that was copied and restored as part of backing up $PGDATA.
*
* We could try to optimize this slightly by checking the local copy
* lastchange timestamp against the archived copy, but we have no API to
* do this, nor can we guarantee that the lastchange timestamp was
* preserved correctly when we copied to archive. Our aim is robustness,
* so we elect not to do this.
*
* If we cannot obtain the log file from the archive, however, we will try
* to use the XLOGDIR file if it exists. This is so that we can make use
* of log segments that weren't yet transferred to the archive.
*
* Notice that we don't actually overwrite any files when we copy back
* from archive because the restore_command may inadvertently restore
* inappropriate xlogs, or they may be corrupt, so we may wish to fallback
* to the segments remaining in current XLOGDIR later. The
* copy-from-archive filename is always the same, ensuring that we don't
* run out of disk space on long recoveries.
*/
snprintf(xlogpath, MAXPGPATH, XLOGDIR "/%s", recovername);
/*
* Make sure there is no existing file named recovername.
*/
if (stat(xlogpath, &stat_buf) != 0)
{
if (errno != ENOENT)
ereport(FATAL,
(errcode_for_file_access(),
errmsg("could not stat file \"%s\": %m",
xlogpath)));
}
else
{
if (unlink(xlogpath) != 0)
ereport(FATAL,
(errcode_for_file_access(),
errmsg("could not remove file \"%s\": %m",
xlogpath)));
}
/*
* Calculate the archive file cutoff point for use during log shipping
* replication. All files earlier than this point can be deleted from the
* archive, though there is no requirement to do so.
*
* If cleanup is not enabled, initialise this with the filename of
* InvalidXLogRecPtr, which will prevent the deletion of any WAL files
* from the archive because of the alphabetic sorting property of WAL
* filenames.
*
* Once we have successfully located the redo pointer of the checkpoint
* from which we start recovery we never request a file prior to the redo
* pointer of the last restartpoint. When redo begins we know that we have
* successfully located it, so there is no need for additional status
* flags to signify the point when we can begin deleting WAL files from
* the archive.
*/
if (cleanupEnabled)
{
GetOldestRestartPoint(&restartRedoPtr, &restartTli);
XLByteToSeg(restartRedoPtr, restartSegNo);
XLogFileName(lastRestartPointFname, restartTli, restartSegNo);
/* we shouldn't need anything earlier than last restart point */
Assert(strcmp(lastRestartPointFname, xlogfname) <= 0);
}
else
XLogFileName(lastRestartPointFname, 0, 0L);
/*
* construct the command to be executed
*/
dp = xlogRestoreCmd;
endp = xlogRestoreCmd + MAXPGPATH - 1;
*endp = '\0';
for (sp = recoveryRestoreCommand; *sp; sp++)
{
if (*sp == '%')
{
switch (sp[1])
{
case 'p':
/* %p: relative path of target file */
sp++;
StrNCpy(dp, xlogpath, endp - dp);
make_native_path(dp);
dp += strlen(dp);
break;
case 'f':
/* %f: filename of desired file */
sp++;
StrNCpy(dp, xlogfname, endp - dp);
dp += strlen(dp);
break;
case 'r':
/* %r: filename of last restartpoint */
sp++;
StrNCpy(dp, lastRestartPointFname, endp - dp);
dp += strlen(dp);
break;
case '%':
/* convert %% to a single % */
sp++;
if (dp < endp)
*dp++ = *sp;
break;
default:
/* otherwise treat the % as not special */
if (dp < endp)
*dp++ = *sp;
break;
}
}
else
{
if (dp < endp)
*dp++ = *sp;
}
}
*dp = '\0';
ereport(DEBUG3,
(errmsg_internal("executing restore command \"%s\"",
xlogRestoreCmd)));
/*
* Check signals before restore command and reset afterwards.
*/
PreRestoreCommand();
/*
* Copy xlog from archival storage to XLOGDIR
*/
rc = system(xlogRestoreCmd);
PostRestoreCommand();
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)
{
int elevel;
/*
* If we find a partial file in standby mode, we assume it's
* because it's just being copied to the archive, and keep
* trying.
*
* Otherwise treat a wrong-sized file as FATAL to ensure the
* DBA would notice it, but is that too strong? We could try
* to plow ahead with a local copy of the file ... but the
* problem is that there probably isn't one, and we'd
* incorrectly conclude we've reached the end of WAL and we're
* done recovering ...
*/
if (StandbyMode && stat_buf.st_size < expectedSize)
elevel = DEBUG1;
else
elevel = FATAL;
ereport(elevel,
(errmsg("archive file \"%s\" has wrong size: %lu instead of %lu",
xlogfname,
(unsigned long) stat_buf.st_size,
(unsigned long) expectedSize)));
return false;
}
else
{
ereport(LOG,
(errmsg("restored log file \"%s\" from archive",
xlogfname)));
strcpy(path, xlogpath);
return true;
}
}
else
{
/* stat failed */
if (errno != ENOENT)
ereport(FATAL,
(errcode_for_file_access(),
errmsg("could not stat file \"%s\": %m",
xlogpath)));
}
}
/*
* Remember, we rollforward UNTIL the restore fails so failure here is
* just part of the process... that makes it difficult to determine
* whether the restore failed because there isn't an archive to restore,
* or because the administrator has specified the restore program
* incorrectly. We have to assume the former.
*
* However, if the failure was due to any sort of signal, it's best to
* punt and abort recovery. (If we "return false" here, upper levels will
* assume that recovery is complete and start up the database!) It's
* essential to abort on child SIGINT and SIGQUIT, because per spec
* system() ignores SIGINT and SIGQUIT while waiting; if we see one of
* those it's a good bet we should have gotten it too.
*
* On SIGTERM, assume we have received a fast shutdown request, and exit
* cleanly. It's pure chance whether we receive the SIGTERM first, or the
* child process. If we receive it first, the signal handler will call
* proc_exit, otherwise we do it here. If we or the child process received
* SIGTERM for any other reason than a fast shutdown request, postmaster
* will perform an immediate shutdown when it sees us exiting
* unexpectedly.
*
* Per the Single Unix Spec, shells report exit status > 128 when a called
* command died on a signal. Also, 126 and 127 are used to report
* problems such as an unfindable command; treat those as fatal errors
* too.
*/
if (WIFSIGNALED(rc) && WTERMSIG(rc) == SIGTERM)
proc_exit(1);
signaled = WIFSIGNALED(rc) || WEXITSTATUS(rc) > 125;
ereport(signaled ? FATAL : DEBUG2,
(errmsg("could not restore file \"%s\" from archive: %s",
xlogfname, wait_result_to_str(rc))));
not_available:
/*
* if an archived file is not available, there might still be a version of
* this file in XLOGDIR, so return that as the filename to open.
*
* In many recovery scenarios we expect this to fail also, but if so that
* just means we've reached the end of WAL.
*/
snprintf(path, MAXPGPATH, XLOGDIR "/%s", xlogfname);
return false;
}
/*
* Attempt to execute an external shell command during recovery.
*
* 'command' is the shell command to be executed, 'commandName' is a
* human-readable name describing the command emitted in the logs. If
* 'failOnSignal' is true and the command is killed by a signal, a FATAL
* error is thrown. Otherwise a WARNING is emitted.
*
* This is currently used for recovery_end_command and archive_cleanup_command.
*/
void
ExecuteRecoveryCommand(char *command, char *commandName, bool failOnSignal)
{
char xlogRecoveryCmd[MAXPGPATH];
char lastRestartPointFname[MAXPGPATH];
char *dp;
char *endp;
const char *sp;
int rc;
bool signaled;
XLogSegNo restartSegNo;
XLogRecPtr restartRedoPtr;
TimeLineID restartTli;
Assert(command && commandName);
/*
* Calculate the archive file cutoff point for use during log shipping
* replication. All files earlier than this point can be deleted from the
* archive, though there is no requirement to do so.
*/
GetOldestRestartPoint(&restartRedoPtr, &restartTli);
XLByteToSeg(restartRedoPtr, restartSegNo);
XLogFileName(lastRestartPointFname, restartTli, restartSegNo);
/*
* construct the command to be executed
*/
dp = xlogRecoveryCmd;
endp = xlogRecoveryCmd + MAXPGPATH - 1;
*endp = '\0';
for (sp = command; *sp; sp++)
{
if (*sp == '%')
{
switch (sp[1])
{
case 'r':
/* %r: filename of last restartpoint */
sp++;
StrNCpy(dp, lastRestartPointFname, endp - dp);
dp += strlen(dp);
break;
case '%':
/* convert %% to a single % */
sp++;
if (dp < endp)
*dp++ = *sp;
break;
default:
/* otherwise treat the % as not special */
if (dp < endp)
*dp++ = *sp;
break;
}
}
else
{
if (dp < endp)
*dp++ = *sp;
}
}
*dp = '\0';
ereport(DEBUG3,
(errmsg_internal("executing %s \"%s\"", commandName, command)));
/*
* execute the constructed command
*/
rc = system(xlogRecoveryCmd);
if (rc != 0)
{
/*
* If the failure was due to any sort of signal, it's best to punt and
* abort recovery. See also detailed comments on signals in
* RestoreArchivedFile().
*/
signaled = WIFSIGNALED(rc) || WEXITSTATUS(rc) > 125;
ereport((signaled && failOnSignal) ? FATAL : WARNING,
/*------
translator: First %s represents a recovery.conf parameter name like
"recovery_end_command", the 2nd is the value of that parameter, the
third an already translated error message. */
(errmsg("%s \"%s\": %s", commandName,
command, wait_result_to_str(rc))));
}
}
/*
* Run ssl_passphrase_command
*
* prompt will be substituted for %p. is_server_start determines the loglevel
* of error messages.
*
* The result will be put in buffer buf, which is of size size. The return
* value is the length of the actual result.
*/
int
run_ssl_passphrase_command(const char *prompt, bool is_server_start, char *buf, int size)
{
int loglevel = is_server_start ? ERROR : LOG;
StringInfoData command;
char *p;
FILE *fh;
int pclose_rc;
size_t len = 0;
Assert(prompt);
Assert(size > 0);
buf[0] = '\0';
initStringInfo(&command);
for (p = ssl_passphrase_command; *p; p++)
{
if (p[0] == '%')
{
switch (p[1])
{
case 'p':
appendStringInfoString(&command, prompt);
p++;
break;
case '%':
appendStringInfoChar(&command, '%');
p++;
break;
default:
appendStringInfoChar(&command, p[0]);
}
}
else
appendStringInfoChar(&command, p[0]);
}
fh = OpenPipeStream(command.data, "r");
if (fh == NULL)
{
ereport(loglevel,
(errcode_for_file_access(),
errmsg("could not execute command \"%s\": %m",
command.data)));
goto error;
}
if (!fgets(buf, size, fh))
{
if (ferror(fh))
{
ereport(loglevel,
(errcode_for_file_access(),
errmsg("could not read from command \"%s\": %m",
command.data)));
goto error;
}
}
pclose_rc = ClosePipeStream(fh);
if (pclose_rc == -1)
{
ereport(loglevel,
(errcode_for_file_access(),
errmsg("could not close pipe to external command: %m")));
goto error;
}
else if (pclose_rc != 0)
{
ereport(loglevel,
(errcode_for_file_access(),
errmsg("command \"%s\" failed",
command.data),
errdetail_internal("%s", wait_result_to_str(pclose_rc))));
goto error;
}
/* strip trailing newline */
len = strlen(buf);
if (len > 0 && buf[len - 1] == '\n')
buf[--len] = '\0';
error:
pfree(command.data);
return len;
}
