Revert refactoring of restore command code to shell_restore.c

This reverts commits 24c35ec and 57169ad.  PreRestoreCommand() and
PostRestoreCommand() need to be put closer to the system() call calling
a restore_command, as they enable in_restore_command for the startup
process which would in turn trigger an immediate proc_exit() in the
SIGTERM handler.  Perhaps we could get rid of this behavior entirely,
but 24c35ec has made the window where the flag is enabled much larger
than it was, and any Postgres-like actions (palloc, etc.) taken by code
paths while the flag is enabled could lead to more severe issues in the
shutdown processing.

Note that curculio has showed that there are much more problems in this
area, unrelated to this change, actually, hence the issues related to
that had better be addressed first.  Keeping the code of HEAD in line
with the stable branches should make that a bit easier.

Per discussion with Andres Freund and Nathan Bossart.

Discussion: https://postgr.es/m/Y979NR3U5VnWrTwB@paquier.xyz

1 files changed, 0 insertions, 171 deletions

diff --git a/src/backend/access/transam/shell_restore.c b/src/backend/access/transam/shell_restore.c
deleted file mode 100644
index 8458209f490..00000000000
--- a/src/backend/access/transam/shell_restore.c
+++ /dev/null
@@ -1,171 +0,0 @@
-/*-------------------------------------------------------------------------
- *
- * shell_restore.c
- *		Recovery functions for a user-specified shell command.
- *
- * These recovery functions use a user-specified shell command (e.g. based
- * on the GUC restore_command).
- *
- * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
- * Portions Copyright (c) 1994, Regents of the University of California
- *
- * src/backend/access/transam/shell_restore.c
- *
- *-------------------------------------------------------------------------
- */
-
-#include "postgres.h"
-
-#include <signal.h>
-
-#include "access/xlogarchive.h"
-#include "access/xlogrecovery.h"
-#include "common/percentrepl.h"
-#include "storage/ipc.h"
-#include "utils/wait_event.h"
-
-static bool ExecuteRecoveryCommand(const char *command,
-								   const char *commandName,
-								   bool failOnSignal,
-								   bool exitOnSigterm,
-								   uint32 wait_event_info,
-								   int fail_elevel);
-
-/*
- * Attempt to execute a shell-based restore command.
- *
- * Returns true if the command has succeeded, false otherwise.
- */
-bool
-shell_restore(const char *file, const char *path,
-			  const char *lastRestartPointFileName)
-{
-	char	   *nativePath = pstrdup(path);
-	char	   *cmd;
-	bool		ret;
-
-	/* Build the restore command to execute */
-	make_native_path(nativePath);
-	cmd = replace_percent_placeholders(recoveryRestoreCommand,
-									   "restore_command", "frp", file,
-									   lastRestartPointFileName,
-									   nativePath);
-	pfree(nativePath);
-
-	/*
-	 * 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.
-	 *
-	 * We treat hard shell errors such as "command not found" as fatal, too.
-	 */
-	ret = ExecuteRecoveryCommand(cmd, "restore_command",
-								 true,	/* failOnSignal */
-								 true,	/* exitOnSigterm */
-								 WAIT_EVENT_RESTORE_COMMAND, DEBUG2);
-	pfree(cmd);
-
-	return ret;
-}
-
-/*
- * Attempt to execute a shell-based archive cleanup command.
- */
-void
-shell_archive_cleanup(const char *lastRestartPointFileName)
-{
-	char	   *cmd;
-
-	cmd = replace_percent_placeholders(archiveCleanupCommand,
-									   "archive_cleanup_command",
-									   "r", lastRestartPointFileName);
-	(void) ExecuteRecoveryCommand(cmd, "archive_cleanup_command", false, false,
-								  WAIT_EVENT_ARCHIVE_CLEANUP_COMMAND, WARNING);
-	pfree(cmd);
-}
-
-/*
- * Attempt to execute a shell-based end-of-recovery command.
- */
-void
-shell_recovery_end(const char *lastRestartPointFileName)
-{
-	char	   *cmd;
-
-	cmd = replace_percent_placeholders(recoveryEndCommand,
-									   "recovery_end_command",
-									   "r", lastRestartPointFileName);
-	(void) ExecuteRecoveryCommand(cmd, "recovery_end_command", true, false,
-								  WAIT_EVENT_RECOVERY_END_COMMAND, WARNING);
-	pfree(cmd);
-}
-
-/*
- * 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, 'fail_elevel' is used for the log message.
- * If 'exitOnSigterm' is true and the command is killed by SIGTERM, we exit
- * immediately.
- *
- * Returns whether the command succeeded.
- */
-static bool
-ExecuteRecoveryCommand(const char *command, const char *commandName,
-					   bool failOnSignal, bool exitOnSigterm,
-					   uint32 wait_event_info, int fail_elevel)
-{
-	int			rc;
-
-	Assert(command && commandName);
-
-	ereport(DEBUG3,
-			(errmsg_internal("executing %s \"%s\"", commandName, command)));
-
-	/*
-	 * execute the constructed command
-	 */
-	fflush(NULL);
-	pgstat_report_wait_start(wait_event_info);
-	rc = system(command);
-	pgstat_report_wait_end();
-
-	if (rc != 0)
-	{
-		if (exitOnSigterm && wait_result_is_signal(rc, SIGTERM))
-			proc_exit(1);
-
-		/*
-		 * If the failure was due to any sort of signal, it's best to punt and
-		 * abort recovery.  See comments in shell_restore().
-		 */
-		ereport((failOnSignal && wait_result_is_any_signal(rc, true)) ? FATAL : fail_elevel,
-		/*------
-		   translator: First %s represents a postgresql.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))));
-	}
-
-	return (rc == 0);
-}