Use printf's %m format instead of strerror(errno) in more places

Most callers of strerror() are removed from the backend code.  The
remaining callers require special handling with a saved errno from a
previous system call.  The frontend code still needs strerror() where
error states need to be handled outside of fprintf.

Note that pg_regress is not changed to use %m as the TAP output may
clobber errno, since those functions call fprintf() and friends before
evaluating the format string.

Support for %m in src/port/snprintf.c has been added in d6c55de1f9,
hence all the stable branches currently supported include it.

Author: Dagfinn Ilmari Mannsåker
Discussion: https://postgr.es/m/87sf13jhuw.fsf@wibble.ilmari.org

src/backend/postmaster/postmaster.c

@@ -1375,12 +1375,12 @@ PostmasterMain(int argc, char *argv[])
 
 			/* Make PID file world readable */
 			if (chmod(external_pid_file, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH) != 0)
-				write_stderr("%s: could not change permissions of external PID file \"%s\": %s\n",
+				write_stderr("%s: could not change permissions of external PID file \"%s\": %m\n",
-							 progname, external_pid_file, strerror(errno));
+							 progname, external_pid_file);
 		}
 		else
-			write_stderr("%s: could not write external PID file \"%s\": %s\n",
+			write_stderr("%s: could not write external PID file \"%s\": %m\n",
-						 progname, external_pid_file, strerror(errno));
+						 progname, external_pid_file);
 
 		on_proc_exit(unlink_external_pid_file, 0);
 	}
@@ -1589,8 +1589,8 @@ checkControlFile(void)
 	{
 		write_stderr("%s: could not find the database system\n"
 					 "Expected to find it in the directory \"%s\",\n"
-					 "but could not open file \"%s\": %s\n",
+					 "but could not open file \"%s\": %m\n",
-					 progname, DataDir, path, strerror(errno));
+					 progname, DataDir, path);
 		ExitPostmaster(2);
 	}
 	FreeFile(fp);
@@ -6277,15 +6277,13 @@ read_backend_variables(char *id, Port **port, BackgroundWorker **worker)
 	fp = AllocateFile(id, PG_BINARY_R);
 	if (!fp)
 	{
-		write_stderr("could not open backend variables file \"%s\": %s\n",
+		write_stderr("could not open backend variables file \"%s\": %m\n", id);
-					 id, strerror(errno));
 		exit(1);
 	}
 
 	if (fread(&param, sizeof(param), 1, fp) != 1)
 	{
-		write_stderr("could not read from backend variables file \"%s\": %s\n",
+		write_stderr("could not read from backend variables file \"%s\": %m\n", id);
-					 id, strerror(errno));
 		exit(1);
 	}
 
@@ -6293,8 +6291,7 @@ read_backend_variables(char *id, Port **port, BackgroundWorker **worker)
 	FreeFile(fp);
 	if (unlink(id) != 0)
 	{
-		write_stderr("could not remove file \"%s\": %s\n",
+		write_stderr("could not remove file \"%s\": %m\n", id);
-					 id, strerror(errno));
 		exit(1);
 	}
 #else

src/backend/postmaster/syslogger.c

@@ -1173,7 +1173,7 @@ write_syslogger_file(const char *buffer, int count, int destination)
 	 * to our input pipe which would result in a different sort of looping.
 	 */
 	if (rc != count)
-		write_stderr("could not write to log file: %s\n", strerror(errno));
+		write_stderr("could not write to log file: %m\n");
 }
 
 #ifdef WIN32

src/backend/utils/misc/guc.c

@@ -1799,10 +1799,9 @@ SelectConfigFiles(const char *userDoption, const char *progname)
 
 	if (configdir && stat(configdir, &stat_buf) != 0)
 	{
-		write_stderr("%s: could not access directory \"%s\": %s\n",
+		write_stderr("%s: could not access directory \"%s\": %m\n",
 					 progname,
-					 configdir,
+					 configdir);
-					 strerror(errno));
 		if (errno == ENOENT)
 			write_stderr("Run initdb or pg_basebackup to initialize a PostgreSQL data directory.\n");
 		return false;
@@ -1851,8 +1850,8 @@ SelectConfigFiles(const char *userDoption, const char *progname)
 	 */
 	if (stat(ConfigFileName, &stat_buf) != 0)
 	{
-		write_stderr("%s: could not access the server configuration file \"%s\": %s\n",
+		write_stderr("%s: could not access the server configuration file \"%s\": %m\n",
-					 progname, ConfigFileName, strerror(errno));
+					 progname, ConfigFileName);
 		free(configdir);
 		return false;
 	}

src/bin/initdb/findtimezone.c

@@ -680,8 +680,8 @@ scan_available_timezones(char *tzdir, char *tzdirsub, struct tztry *tt,
 		if (stat(tzdir, &statbuf) != 0)
 		{
 #ifdef DEBUG_IDENTIFY_TIMEZONE
-			fprintf(stderr, "could not stat \"%s\": %s\n",
+			fprintf(stderr, "could not stat \"%s\": %m\n",
-					tzdir, strerror(errno));
+					tzdir);
 #endif
 			tzdir[tzdir_orig_len] = '\0';
 			continue;

src/bin/pg_ctl/pg_ctl.c

@@ -254,8 +254,8 @@ get_pgpid(bool is_status_request)
 			write_stderr(_("%s: directory \"%s\" does not exist\n"), progname,
 						 pg_data);
 		else
-			write_stderr(_("%s: could not access directory \"%s\": %s\n"), progname,
+			write_stderr(_("%s: could not access directory \"%s\": %m\n"), progname,
-						 pg_data, strerror(errno));
+						 pg_data);
 
 		/*
 		 * The Linux Standard Base Core Specification 3.1 says this should
@@ -280,8 +280,8 @@ get_pgpid(bool is_status_request)
 			return 0;
 		else
 		{
-			write_stderr(_("%s: could not open PID file \"%s\": %s\n"),
+			write_stderr(_("%s: could not open PID file \"%s\": %m\n"),
-						 progname, pid_file, strerror(errno));
+						 progname, pid_file);
 			exit(1);
 		}
 	}
@@ -454,8 +454,8 @@ start_postmaster(void)
 	if (pm_pid < 0)
 	{
 		/* fork failed */
-		write_stderr(_("%s: could not start server: %s\n"),
+		write_stderr(_("%s: could not start server: %m\n"),
-					 progname, strerror(errno));
+					 progname);
 		exit(1);
 	}
 	if (pm_pid > 0)
@@ -474,8 +474,8 @@ start_postmaster(void)
 #ifdef HAVE_SETSID
 	if (setsid() < 0)
 	{
-		write_stderr(_("%s: could not start server due to setsid() failure: %s\n"),
+		write_stderr(_("%s: could not start server due to setsid() failure: %m\n"),
-					 progname, strerror(errno));
+					 progname);
 		exit(1);
 	}
 #endif
@@ -496,8 +496,8 @@ start_postmaster(void)
 	(void) execl("/bin/sh", "/bin/sh", "-c", cmd, (char *) NULL);
 
 	/* exec failed */
-	write_stderr(_("%s: could not start server: %s\n"),
+	write_stderr(_("%s: could not start server: %m\n"),
-				 progname, strerror(errno));
+				 progname);
 	exit(1);
 
 	return 0;					/* keep dumb compilers quiet */
@@ -544,8 +544,8 @@ start_postmaster(void)
 			 */
 			if (errno != ENOENT)
 			{
-				write_stderr(_("%s: could not open log file \"%s\": %s\n"),
+				write_stderr(_("%s: could not open log file \"%s\": %m\n"),
-							 progname, log_file, strerror(errno));
+							 progname, log_file);
 				exit(1);
 			}
 		}
@@ -851,8 +851,8 @@ trap_sigint_during_startup(SIGNAL_ARGS)
 	if (postmasterPID != -1)
 	{
 		if (kill(postmasterPID, SIGINT) != 0)
-			write_stderr(_("%s: could not send stop signal (PID: %d): %s\n"),
+			write_stderr(_("%s: could not send stop signal (PID: %d): %m\n"),
-						 progname, (int) postmasterPID, strerror(errno));
+						 progname, (int) postmasterPID);
 	}
 
 	/*
@@ -1035,8 +1035,7 @@ do_stop(void)
 
 	if (kill(pid, sig) != 0)
 	{
-		write_stderr(_("%s: could not send stop signal (PID: %d): %s\n"), progname, (int) pid,
+		write_stderr(_("%s: could not send stop signal (PID: %d): %m\n"), progname, (int) pid);
-					 strerror(errno));
 		exit(1);
 	}
 
@@ -1103,8 +1102,7 @@ do_restart(void)
 	{
 		if (kill(pid, sig) != 0)
 		{
-			write_stderr(_("%s: could not send stop signal (PID: %d): %s\n"), progname, (int) pid,
+			write_stderr(_("%s: could not send stop signal (PID: %d): %m\n"), progname, (int) pid);
-						 strerror(errno));
 			exit(1);
 		}
 
@@ -1159,8 +1157,8 @@ do_reload(void)
 
 	if (kill(pid, sig) != 0)
 	{
-		write_stderr(_("%s: could not send reload signal (PID: %d): %s\n"),
+		write_stderr(_("%s: could not send reload signal (PID: %d): %m\n"),
-					 progname, (int) pid, strerror(errno));
+					 progname, (int) pid);
 		exit(1);
 	}
 
@@ -1207,25 +1205,25 @@ do_promote(void)
 
 	if ((prmfile = fopen(promote_file, "w")) == NULL)
 	{
-		write_stderr(_("%s: could not create promote signal file \"%s\": %s\n"),
+		write_stderr(_("%s: could not create promote signal file \"%s\": %m\n"),
-					 progname, promote_file, strerror(errno));
+					 progname, promote_file);
 		exit(1);
 	}
 	if (fclose(prmfile))
 	{
-		write_stderr(_("%s: could not write promote signal file \"%s\": %s\n"),
+		write_stderr(_("%s: could not write promote signal file \"%s\": %m\n"),
-					 progname, promote_file, strerror(errno));
+					 progname, promote_file);
 		exit(1);
 	}
 
 	sig = SIGUSR1;
 	if (kill(pid, sig) != 0)
 	{
-		write_stderr(_("%s: could not send promote signal (PID: %d): %s\n"),
+		write_stderr(_("%s: could not send promote signal (PID: %d): %m\n"),
-					 progname, (int) pid, strerror(errno));
+					 progname, (int) pid);
 		if (unlink(promote_file) != 0)
-			write_stderr(_("%s: could not remove promote signal file \"%s\": %s\n"),
+			write_stderr(_("%s: could not remove promote signal file \"%s\": %m\n"),
-						 progname, promote_file, strerror(errno));
+						 progname, promote_file);
 		exit(1);
 	}
 
@@ -1280,25 +1278,25 @@ do_logrotate(void)
 
 	if ((logrotatefile = fopen(logrotate_file, "w")) == NULL)
 	{
-		write_stderr(_("%s: could not create log rotation signal file \"%s\": %s\n"),
+		write_stderr(_("%s: could not create log rotation signal file \"%s\": %m\n"),
-					 progname, logrotate_file, strerror(errno));
+					 progname, logrotate_file);
 		exit(1);
 	}
 	if (fclose(logrotatefile))
 	{
-		write_stderr(_("%s: could not write log rotation signal file \"%s\": %s\n"),
+		write_stderr(_("%s: could not write log rotation signal file \"%s\": %m\n"),
-					 progname, logrotate_file, strerror(errno));
+					 progname, logrotate_file);
 		exit(1);
 	}
 
 	sig = SIGUSR1;
 	if (kill(pid, sig) != 0)
 	{
-		write_stderr(_("%s: could not send log rotation signal (PID: %d): %s\n"),
+		write_stderr(_("%s: could not send log rotation signal (PID: %d): %m\n"),
-					 progname, (int) pid, strerror(errno));
+					 progname, (int) pid);
 		if (unlink(logrotate_file) != 0)
-			write_stderr(_("%s: could not remove log rotation signal file \"%s\": %s\n"),
+			write_stderr(_("%s: could not remove log rotation signal file \"%s\": %m\n"),
-						 progname, logrotate_file, strerror(errno));
+						 progname, logrotate_file);
 		exit(1);
 	}
 
@@ -1396,8 +1394,8 @@ do_kill(pid_t pid)
 {
 	if (kill(pid, sig) != 0)
 	{
-		write_stderr(_("%s: could not send signal %d (PID: %d): %s\n"),
+		write_stderr(_("%s: could not send signal %d (PID: %d): %m\n"),
-					 progname, sig, (int) pid, strerror(errno));
+					 progname, sig, (int) pid);
 		exit(1);
 	}
 }

src/bin/pg_dump/compress_gzip.c

@@ -292,7 +292,7 @@ Gzip_getc(CompressFileHandle *CFH)
 	if (ret == EOF)
 	{
 		if (!gzeof(gzfp))
-			pg_fatal("could not read from input file: %s", strerror(errno));
+			pg_fatal("could not read from input file: %m");
 		else
 			pg_fatal("could not read from input file: end of file");
 	}

src/bin/pg_dump/compress_none.c

@@ -94,8 +94,7 @@ read_none(void *ptr, size_t size, size_t *rsize, CompressFileHandle *CFH)
 
 	ret = fread(ptr, 1, size, fp);
 	if (ret != size && !feof(fp))
-		pg_fatal("could not read from input file: %s",
+		pg_fatal("could not read from input file: %m");
-				 strerror(errno));
 
 	if (rsize)
 		*rsize = ret;
@@ -137,7 +136,7 @@ getc_none(CompressFileHandle *CFH)
 	if (ret == EOF)
 	{
 		if (!feof(fp))
-			pg_fatal("could not read from input file: %s", strerror(errno));
+			pg_fatal("could not read from input file: %m");
 		else
 			pg_fatal("could not read from input file: end of file");
 	}

src/bin/pg_upgrade/check.c

@@ -505,8 +505,8 @@ create_script_for_old_cluster_deletion(char **deletion_script_file_name)
 	prep_status("Creating script to delete old cluster");
 
 	if ((script = fopen_priv(*deletion_script_file_name, "w")) == NULL)
-		pg_fatal("could not open file \"%s\": %s",
+		pg_fatal("could not open file \"%s\": %m",
-				 *deletion_script_file_name, strerror(errno));
+				 *deletion_script_file_name);
 
 #ifndef WIN32
 	/* add shebang header */
@@ -556,8 +556,8 @@ create_script_for_old_cluster_deletion(char **deletion_script_file_name)
 
 #ifndef WIN32
 	if (chmod(*deletion_script_file_name, S_IRWXU) != 0)
-		pg_fatal("could not add execute permission to file \"%s\": %s",
+		pg_fatal("could not add execute permission to file \"%s\": %m",
-				 *deletion_script_file_name, strerror(errno));
+				 *deletion_script_file_name);
 #endif
 
 	check_ok();
@@ -678,8 +678,7 @@ check_proper_datallowconn(ClusterInfo *cluster)
 			if (strcmp(datallowconn, "f") == 0)
 			{
 				if (script == NULL && (script = fopen_priv(output_path, "w")) == NULL)
-					pg_fatal("could not open file \"%s\": %s",
+					pg_fatal("could not open file \"%s\": %m", output_path);
-							 output_path, strerror(errno));
 
 				fprintf(script, "%s\n", datname);
 			}
@@ -794,8 +793,7 @@ check_for_isn_and_int8_passing_mismatch(ClusterInfo *cluster)
 		for (rowno = 0; rowno < ntups; rowno++)
 		{
 			if (script == NULL && (script = fopen_priv(output_path, "w")) == NULL)
-				pg_fatal("could not open file \"%s\": %s",
+				pg_fatal("could not open file \"%s\": %m", output_path);
-						 output_path, strerror(errno));
 			if (!db_used)
 			{
 				fprintf(script, "In database: %s\n", active_db->db_name);
@@ -889,8 +887,7 @@ check_for_user_defined_postfix_ops(ClusterInfo *cluster)
 		{
 			if (script == NULL &&
 				(script = fopen_priv(output_path, "w")) == NULL)
-				pg_fatal("could not open file \"%s\": %s",
+				pg_fatal("could not open file \"%s\": %m", output_path);
-						 output_path, strerror(errno));
 			if (!db_used)
 			{
 				fprintf(script, "In database: %s\n", active_db->db_name);
@@ -1018,8 +1015,7 @@ check_for_incompatible_polymorphics(ClusterInfo *cluster)
 		{
 			if (script == NULL &&
 				(script = fopen_priv(output_path, "w")) == NULL)
-				pg_fatal("could not open file \"%s\": %s",
+				pg_fatal("could not open file \"%s\": %m", output_path);
-						 output_path, strerror(errno));
 			if (!db_used)
 			{
 				fprintf(script, "In database: %s\n", active_db->db_name);
@@ -1095,8 +1091,7 @@ check_for_tables_with_oids(ClusterInfo *cluster)
 		for (rowno = 0; rowno < ntups; rowno++)
 		{
 			if (script == NULL && (script = fopen_priv(output_path, "w")) == NULL)
-				pg_fatal("could not open file \"%s\": %s",
+				pg_fatal("could not open file \"%s\": %m", output_path);
-						 output_path, strerror(errno));
 			if (!db_used)
 			{
 				fprintf(script, "In database: %s\n", active_db->db_name);
@@ -1374,8 +1369,7 @@ check_for_pg_role_prefix(ClusterInfo *cluster)
 	for (int rowno = 0; rowno < ntups; rowno++)
 	{
 		if (script == NULL && (script = fopen_priv(output_path, "w")) == NULL)
-			pg_fatal("could not open file \"%s\": %s",
+			pg_fatal("could not open file \"%s\": %m", output_path);
-					 output_path, strerror(errno));
 		fprintf(script, "%s (oid=%s)\n",
 				PQgetvalue(res, rowno, i_rolname),
 				PQgetvalue(res, rowno, i_roloid));
@@ -1448,8 +1442,7 @@ check_for_user_defined_encoding_conversions(ClusterInfo *cluster)
 		{
 			if (script == NULL &&
 				(script = fopen_priv(output_path, "w")) == NULL)
-				pg_fatal("could not open file \"%s\": %s",
+				pg_fatal("could not open file \"%s\": %m", output_path);
-						 output_path, strerror(errno));
 			if (!db_used)
 			{
 				fprintf(script, "In database: %s\n", active_db->db_name);
@@ -1631,8 +1624,7 @@ check_old_cluster_for_valid_slots(bool live_check)
 			{
 				if (script == NULL &&
 					(script = fopen_priv(output_path, "w")) == NULL)
-					pg_fatal("could not open file \"%s\": %s",
+					pg_fatal("could not open file \"%s\": %m", output_path);
-							 output_path, strerror(errno));
 
 				fprintf(script, "The slot \"%s\" is invalid\n",
 						slot->slotname);
@@ -1651,8 +1643,7 @@ check_old_cluster_for_valid_slots(bool live_check)
 			{
 				if (script == NULL &&
 					(script = fopen_priv(output_path, "w")) == NULL)
-					pg_fatal("could not open file \"%s\": %s",
+					pg_fatal("could not open file \"%s\": %m", output_path);
-							 output_path, strerror(errno));
 
 				fprintf(script,
 						"The slot \"%s\" has not consumed the WAL yet\n",
@@ -1721,8 +1712,7 @@ check_old_cluster_subscription_state(void)
 			for (int i = 0; i < ntup; i++)
 			{
 				if (script == NULL && (script = fopen_priv(output_path, "w")) == NULL)
-					pg_fatal("could not open file \"%s\": %s",
+					pg_fatal("could not open file \"%s\": %m", output_path);
-							 output_path, strerror(errno));
 				fprintf(script, "The replication origin is missing for database:\"%s\" subscription:\"%s\"\n",
 						PQgetvalue(res, i, 0),
 						PQgetvalue(res, i, 1));
@@ -1774,8 +1764,7 @@ check_old_cluster_subscription_state(void)
 		for (int i = 0; i < ntup; i++)
 		{
 			if (script == NULL && (script = fopen_priv(output_path, "w")) == NULL)
-				pg_fatal("could not open file \"%s\": %s",
+				pg_fatal("could not open file \"%s\": %m", output_path);
-						 output_path, strerror(errno));
 
 			fprintf(script, "The table sync state \"%s\" is not allowed for database:\"%s\" subscription:\"%s\" schema:\"%s\" relation:\"%s\"\n",
 					PQgetvalue(res, i, 0),

src/bin/pg_upgrade/controldata.c

@@ -126,8 +126,7 @@ get_control_data(ClusterInfo *cluster, bool live_check)
 		fflush(NULL);
 
 		if ((output = popen(cmd, "r")) == NULL)
-			pg_fatal("could not get control data using %s: %s",
+			pg_fatal("could not get control data using %s: %m", cmd);
-					 cmd, strerror(errno));
 
 		/* we have the result of cmd in "output". so parse it line by line now */
 		while (fgets(bufin, sizeof(bufin), output))
@@ -197,8 +196,7 @@ get_control_data(ClusterInfo *cluster, bool live_check)
 	fflush(NULL);
 
 	if ((output = popen(cmd, "r")) == NULL)
-		pg_fatal("could not get control data using %s: %s",
+		pg_fatal("could not get control data using %s: %m", cmd);
-				 cmd, strerror(errno));
 
 	/* Only in <= 9.2 */
 	if (GET_MAJOR_VERSION(cluster->major_version) <= 902)

src/bin/pg_upgrade/exec.c

@@ -44,8 +44,7 @@ get_bin_version(ClusterInfo *cluster)
 
 	if ((output = popen(cmd, "r")) == NULL ||
 		fgets(cmd_output, sizeof(cmd_output), output) == NULL)
-		pg_fatal("could not get pg_ctl version data using %s: %s",
+		pg_fatal("could not get pg_ctl version data using %s: %m", cmd);
-				 cmd, strerror(errno));
 
 	rc = pclose(output);
 	if (rc != 0)
@@ -242,8 +241,7 @@ pid_lock_file_exists(const char *datadir)
 	{
 		/* ENOTDIR means we will throw a more useful error later */
 		if (errno != ENOENT && errno != ENOTDIR)
-			pg_fatal("could not open file \"%s\" for reading: %s",
+			pg_fatal("could not open file \"%s\" for reading: %m", path);
-					 path, strerror(errno));
 
 		return false;
 	}
@@ -322,8 +320,8 @@ check_single_dir(const char *pg_data, const char *subdir)
 			 subdir);
 
 	if (stat(subDirName, &statBuf) != 0)
-		report_status(PG_FATAL, "check for \"%s\" failed: %s",
+		report_status(PG_FATAL, "check for \"%s\" failed: %m",
-					  subDirName, strerror(errno));
+					  subDirName);
 	else if (!S_ISDIR(statBuf.st_mode))
 		report_status(PG_FATAL, "\"%s\" is not a directory",
 					  subDirName);
@@ -388,8 +386,8 @@ check_bin_dir(ClusterInfo *cluster, bool check_versions)
 
 	/* check bindir */
 	if (stat(cluster->bindir, &statBuf) != 0)
-		report_status(PG_FATAL, "check for \"%s\" failed: %s",
+		report_status(PG_FATAL, "check for \"%s\" failed: %m",
-					  cluster->bindir, strerror(errno));
+					  cluster->bindir);
 	else if (!S_ISDIR(statBuf.st_mode))
 		report_status(PG_FATAL, "\"%s\" is not a directory",
 					  cluster->bindir);

src/bin/pg_upgrade/file.c

@@ -41,20 +41,20 @@ cloneFile(const char *src, const char *dst,
 {
 #if defined(HAVE_COPYFILE) && defined(COPYFILE_CLONE_FORCE)
 	if (copyfile(src, dst, NULL, COPYFILE_CLONE_FORCE) < 0)
-		pg_fatal("error while cloning relation \"%s.%s\" (\"%s\" to \"%s\"): %s",
+		pg_fatal("error while cloning relation \"%s.%s\" (\"%s\" to \"%s\"): %m",
-				 schemaName, relName, src, dst, strerror(errno));
+				 schemaName, relName, src, dst);
 #elif defined(__linux__) && defined(FICLONE)
 	int			src_fd;
 	int			dest_fd;
 
 	if ((src_fd = open(src, O_RDONLY | PG_BINARY, 0)) < 0)
-		pg_fatal("error while cloning relation \"%s.%s\": could not open file \"%s\": %s",
+		pg_fatal("error while cloning relation \"%s.%s\": could not open file \"%s\": %m",
-				 schemaName, relName, src, strerror(errno));
+				 schemaName, relName, src);
 
 	if ((dest_fd = open(dst, O_RDWR | O_CREAT | O_EXCL | PG_BINARY,
 						pg_file_create_mode)) < 0)
-		pg_fatal("error while cloning relation \"%s.%s\": could not create file \"%s\": %s",
+		pg_fatal("error while cloning relation \"%s.%s\": could not create file \"%s\": %m",
-				 schemaName, relName, dst, strerror(errno));
+				 schemaName, relName, dst);
 
 	if (ioctl(dest_fd, FICLONE, src_fd) < 0)
 	{
@@ -88,13 +88,13 @@ copyFile(const char *src, const char *dst,
 	char	   *buffer;
 
 	if ((src_fd = open(src, O_RDONLY | PG_BINARY, 0)) < 0)
-		pg_fatal("error while copying relation \"%s.%s\": could not open file \"%s\": %s",
+		pg_fatal("error while copying relation \"%s.%s\": could not open file \"%s\": %m",
-				 schemaName, relName, src, strerror(errno));
+				 schemaName, relName, src);
 
 	if ((dest_fd = open(dst, O_RDWR | O_CREAT | O_EXCL | PG_BINARY,
 						pg_file_create_mode)) < 0)
-		pg_fatal("error while copying relation \"%s.%s\": could not create file \"%s\": %s",
+		pg_fatal("error while copying relation \"%s.%s\": could not create file \"%s\": %m",
-				 schemaName, relName, dst, strerror(errno));
+				 schemaName, relName, dst);
 
 	/* copy in fairly large chunks for best efficiency */
 #define COPY_BUF_SIZE (50 * BLCKSZ)
@@ -107,8 +107,8 @@ copyFile(const char *src, const char *dst,
 		ssize_t		nbytes = read(src_fd, buffer, COPY_BUF_SIZE);
 
 		if (nbytes < 0)
-			pg_fatal("error while copying relation \"%s.%s\": could not read file \"%s\": %s",
+			pg_fatal("error while copying relation \"%s.%s\": could not read file \"%s\": %m",
-					 schemaName, relName, src, strerror(errno));
+					 schemaName, relName, src);
 
 		if (nbytes == 0)
 			break;
@@ -119,8 +119,8 @@ copyFile(const char *src, const char *dst,
 			/* if write didn't set errno, assume problem is no disk space */
 			if (errno == 0)
 				errno = ENOSPC;
-			pg_fatal("error while copying relation \"%s.%s\": could not write file \"%s\": %s",
+			pg_fatal("error while copying relation \"%s.%s\": could not write file \"%s\": %m",
-					 schemaName, relName, dst, strerror(errno));
+					 schemaName, relName, dst);
 		}
 	}
 
@@ -133,8 +133,8 @@ copyFile(const char *src, const char *dst,
 	if (CopyFile(src, dst, true) == 0)
 	{
 		_dosmaperr(GetLastError());
-		pg_fatal("error while copying relation \"%s.%s\" (\"%s\" to \"%s\"): %s",
+		pg_fatal("error while copying relation \"%s.%s\" (\"%s\" to \"%s\"): %m",
-				 schemaName, relName, src, dst, strerror(errno));
+				 schemaName, relName, src, dst);
 	}
 
 #endif							/* WIN32 */
@@ -157,20 +157,20 @@ copyFileByRange(const char *src, const char *dst,
 	ssize_t		nbytes;
 
 	if ((src_fd = open(src, O_RDONLY | PG_BINARY, 0)) < 0)
-		pg_fatal("error while copying relation \"%s.%s\": could not open file \"%s\": %s",
+		pg_fatal("error while copying relation \"%s.%s\": could not open file \"%s\": %m",
-				 schemaName, relName, src, strerror(errno));
+				 schemaName, relName, src);
 
 	if ((dest_fd = open(dst, O_RDWR | O_CREAT | O_EXCL | PG_BINARY,
 						pg_file_create_mode)) < 0)
-		pg_fatal("error while copying relation \"%s.%s\": could not create file \"%s\": %s",
+		pg_fatal("error while copying relation \"%s.%s\": could not create file \"%s\": %m",
-				 schemaName, relName, dst, strerror(errno));
+				 schemaName, relName, dst);
 
 	do
 	{
 		nbytes = copy_file_range(src_fd, NULL, dest_fd, NULL, SSIZE_MAX, 0);
 		if (nbytes < 0)
-			pg_fatal("error while copying relation \"%s.%s\": could not copy file range from \"%s\" to \"%s\": %s",
+			pg_fatal("error while copying relation \"%s.%s\": could not copy file range from \"%s\" to \"%s\": %m",
-					 schemaName, relName, src, dst, strerror(errno));
+					 schemaName, relName, src, dst);
 	}
 	while (nbytes > 0);
 
@@ -191,8 +191,8 @@ linkFile(const char *src, const char *dst,
 		 const char *schemaName, const char *relName)
 {
 	if (link(src, dst) < 0)
-		pg_fatal("error while creating link for relation \"%s.%s\" (\"%s\" to \"%s\"): %s",
+		pg_fatal("error while creating link for relation \"%s.%s\" (\"%s\" to \"%s\"): %m",
-				 schemaName, relName, src, dst, strerror(errno));
+				 schemaName, relName, src, dst);
 }
 
 
@@ -230,17 +230,17 @@ rewriteVisibilityMap(const char *fromfile, const char *tofile,
 	rewriteVmBytesPerPage = (BLCKSZ - SizeOfPageHeaderData) / 2;
 
 	if ((src_fd = open(fromfile, O_RDONLY | PG_BINARY, 0)) < 0)
-		pg_fatal("error while copying relation \"%s.%s\": could not open file \"%s\": %s",
+		pg_fatal("error while copying relation \"%s.%s\": could not open file \"%s\": %m",
-				 schemaName, relName, fromfile, strerror(errno));
+				 schemaName, relName, fromfile);
 
 	if (fstat(src_fd, &statbuf) != 0)
-		pg_fatal("error while copying relation \"%s.%s\": could not stat file \"%s\": %s",
+		pg_fatal("error while copying relation \"%s.%s\": could not stat file \"%s\": %m",
-				 schemaName, relName, fromfile, strerror(errno));
+				 schemaName, relName, fromfile);
 
 	if ((dst_fd = open(tofile, O_RDWR | O_CREAT | O_EXCL | PG_BINARY,
 					   pg_file_create_mode)) < 0)
-		pg_fatal("error while copying relation \"%s.%s\": could not create file \"%s\": %s",
+		pg_fatal("error while copying relation \"%s.%s\": could not create file \"%s\": %m",
-				 schemaName, relName, tofile, strerror(errno));
+				 schemaName, relName, tofile);
 
 	/* Save old file size */
 	src_filesize = statbuf.st_size;
@@ -263,8 +263,8 @@ rewriteVisibilityMap(const char *fromfile, const char *tofile,
 		if ((bytesRead = read(src_fd, buffer.data, BLCKSZ)) != BLCKSZ)
 		{
 			if (bytesRead < 0)
-				pg_fatal("error while copying relation \"%s.%s\": could not read file \"%s\": %s",
+				pg_fatal("error while copying relation \"%s.%s\": could not read file \"%s\": %m",
-						 schemaName, relName, fromfile, strerror(errno));
+						 schemaName, relName, fromfile);
 			else
 				pg_fatal("error while copying relation \"%s.%s\": partial page found in file \"%s\"",
 						 schemaName, relName, fromfile);
@@ -341,8 +341,8 @@ rewriteVisibilityMap(const char *fromfile, const char *tofile,
 				/* if write didn't set errno, assume problem is no disk space */
 				if (errno == 0)
 					errno = ENOSPC;
-				pg_fatal("error while copying relation \"%s.%s\": could not write file \"%s\": %s",
+				pg_fatal("error while copying relation \"%s.%s\": could not write file \"%s\": %m",
-						 schemaName, relName, tofile, strerror(errno));
+						 schemaName, relName, tofile);
 			}
 
 			/* Advance for next new page */
@@ -368,25 +368,23 @@ check_file_clone(void)
 
 #if defined(HAVE_COPYFILE) && defined(COPYFILE_CLONE_FORCE)
 	if (copyfile(existing_file, new_link_file, NULL, COPYFILE_CLONE_FORCE) < 0)
-		pg_fatal("could not clone file between old and new data directories: %s",
+		pg_fatal("could not clone file between old and new data directories: %m");
-				 strerror(errno));
 #elif defined(__linux__) && defined(FICLONE)
 	{
 		int			src_fd;
 		int			dest_fd;
 
 		if ((src_fd = open(existing_file, O_RDONLY | PG_BINARY, 0)) < 0)
-			pg_fatal("could not open file \"%s\": %s",
+			pg_fatal("could not open file \"%s\": %m",
-					 existing_file, strerror(errno));
+					 existing_file);
 
 		if ((dest_fd = open(new_link_file, O_RDWR | O_CREAT | O_EXCL | PG_BINARY,
 							pg_file_create_mode)) < 0)
-			pg_fatal("could not create file \"%s\": %s",
+			pg_fatal("could not create file \"%s\": %m",
-					 new_link_file, strerror(errno));
+					 new_link_file);
 
 		if (ioctl(dest_fd, FICLONE, src_fd) < 0)
-			pg_fatal("could not clone file between old and new data directories: %s",
+			pg_fatal("could not clone file between old and new data directories: %m");
-					 strerror(errno));
 
 		close(src_fd);
 		close(dest_fd);
@@ -414,17 +412,16 @@ check_copy_file_range(void)
 		int			dest_fd;
 
 		if ((src_fd = open(existing_file, O_RDONLY | PG_BINARY, 0)) < 0)
-			pg_fatal("could not open file \"%s\": %s",
+			pg_fatal("could not open file \"%s\": %m",
-					 existing_file, strerror(errno));
+					 existing_file);
 
 		if ((dest_fd = open(new_link_file, O_RDWR | O_CREAT | O_EXCL | PG_BINARY,
 							pg_file_create_mode)) < 0)
-			pg_fatal("could not create file \"%s\": %s",
+			pg_fatal("could not create file \"%s\": %m",
-					 new_link_file, strerror(errno));
+					 new_link_file);
 
 		if (copy_file_range(src_fd, NULL, dest_fd, NULL, SSIZE_MAX, 0) < 0)
-			pg_fatal("could not copy file range between old and new data directories: %s",
+			pg_fatal("could not copy file range between old and new data directories: %m");
-					 strerror(errno));
 
 		close(src_fd);
 		close(dest_fd);
@@ -447,9 +444,8 @@ check_hard_link(void)
 	unlink(new_link_file);		/* might fail */
 
 	if (link(existing_file, new_link_file) < 0)
-		pg_fatal("could not create hard link between old and new data directories: %s\n"
+		pg_fatal("could not create hard link between old and new data directories: %m\n"
-				 "In link mode the old and new data directories must be on the same file system.",
+				 "In link mode the old and new data directories must be on the same file system.");
-				 strerror(errno));
 
 	unlink(new_link_file);
 }

src/bin/pg_upgrade/function.c

@@ -186,8 +186,7 @@ check_loadable_libraries(void)
 				was_load_failure = true;
 
 				if (script == NULL && (script = fopen_priv(output_path, "w")) == NULL)
-					pg_fatal("could not open file \"%s\": %s",
+					pg_fatal("could not open file \"%s\": %m", output_path);
-							 output_path, strerror(errno));
 				fprintf(script, _("could not load library \"%s\": %s"),
 						lib,
 						PQerrorMessage(conn));

src/bin/pg_upgrade/option.c

@@ -445,8 +445,7 @@ adjust_data_dir(ClusterInfo *cluster)
 
 	if ((output = popen(cmd, "r")) == NULL ||
 		fgets(cmd_output, sizeof(cmd_output), output) == NULL)
-		pg_fatal("could not get data directory using %s: %s",
+		pg_fatal("could not get data directory using %s: %m", cmd);
-				 cmd, strerror(errno));
 
 	rc = pclose(output);
 	if (rc != 0)
@@ -491,16 +490,15 @@ get_sock_dir(ClusterInfo *cluster, bool live_check)
 		snprintf(filename, sizeof(filename), "%s/postmaster.pid",
 				 cluster->pgdata);
 		if ((fp = fopen(filename, "r")) == NULL)
-			pg_fatal("could not open file \"%s\": %s",
+			pg_fatal("could not open file \"%s\": %m", filename);
-					 filename, strerror(errno));
 
 		for (lineno = 1;
 			 lineno <= Max(LOCK_FILE_LINE_PORT, LOCK_FILE_LINE_SOCKET_DIR);
 			 lineno++)
 		{
 			if (fgets(line, sizeof(line), fp) == NULL)
-				pg_fatal("could not read line %d from file \"%s\": %s",
+				pg_fatal("could not read line %d from file \"%s\": %m",
-						 lineno, filename, strerror(errno));
+						 lineno, filename);
 
 			/* potentially overwrite user-supplied value */
 			if (lineno == LOCK_FILE_LINE_PORT)

src/bin/pg_upgrade/parallel.c

@@ -124,7 +124,7 @@ parallel_exec_prog(const char *log_file, const char *opt_log_file,
 			_exit(!exec_prog(log_file, opt_log_file, true, true, "%s", cmd));
 		else if (child < 0)
 			/* fork failed */
-			pg_fatal("could not create worker process: %s", strerror(errno));
+			pg_fatal("could not create worker process: %m");
 #else
 		/* empty array element are always at the end */
 		new_arg = exec_thread_args[parallel_jobs - 1];
@@ -140,7 +140,7 @@ parallel_exec_prog(const char *log_file, const char *opt_log_file,
 		child = (HANDLE) _beginthreadex(NULL, 0, (void *) win32_exec_prog,
 										new_arg, 0, NULL);
 		if (child == 0)
-			pg_fatal("could not create worker thread: %s", strerror(errno));
+			pg_fatal("could not create worker thread: %m");
 
 		thread_handles[parallel_jobs - 1] = child;
 #endif
@@ -232,7 +232,7 @@ parallel_transfer_all_new_dbs(DbInfoArr *old_db_arr, DbInfoArr *new_db_arr,
 		}
 		else if (child < 0)
 			/* fork failed */
-			pg_fatal("could not create worker process: %s", strerror(errno));
+			pg_fatal("could not create worker process: %m");
 #else
 		/* empty array element are always at the end */
 		new_arg = transfer_thread_args[parallel_jobs - 1];
@@ -250,7 +250,7 @@ parallel_transfer_all_new_dbs(DbInfoArr *old_db_arr, DbInfoArr *new_db_arr,
 		child = (HANDLE) _beginthreadex(NULL, 0, (void *) win32_transfer_all_new_dbs,
 										new_arg, 0, NULL);
 		if (child == 0)
-			pg_fatal("could not create worker thread: %s", strerror(errno));
+			pg_fatal("could not create worker thread: %m");
 
 		thread_handles[parallel_jobs - 1] = child;
 #endif
@@ -291,7 +291,7 @@ reap_child(bool wait_for_child)
 #ifndef WIN32
 	child = waitpid(-1, &work_status, wait_for_child ? 0 : WNOHANG);
 	if (child == (pid_t) -1)
-		pg_fatal("%s() failed: %s", "waitpid", strerror(errno));
+		pg_fatal("%s() failed: %m", "waitpid");
 	if (child == 0)
 		return false;			/* no children, or no dead children */
 	if (work_status != 0)
@@ -310,7 +310,7 @@ reap_child(bool wait_for_child)
 	/* get the result */
 	GetExitCodeThread(thread_handles[thread_num], &res);
 	if (res != 0)
-		pg_fatal("child worker exited abnormally: %s", strerror(errno));
+		pg_fatal("child worker exited abnormally: %m");
 
 	/* dispose of handle to stop leaks */
 	CloseHandle(thread_handles[thread_num]);

src/bin/pg_upgrade/pg_upgrade.c

@@ -105,8 +105,8 @@ main(int argc, char **argv)
 	 * output directories with correct permissions.
 	 */
 	if (!GetDataDirectoryCreatePerm(new_cluster.pgdata))
-		pg_fatal("could not read permissions of directory \"%s\": %s",
+		pg_fatal("could not read permissions of directory \"%s\": %m",
-				 new_cluster.pgdata, strerror(errno));
+				 new_cluster.pgdata);
 
 	umask(pg_mode_mask);
 

src/bin/pg_upgrade/relfilenumber.c

@@ -218,9 +218,8 @@ transfer_relfile(FileNameMap *map, const char *type_suffix, bool vm_must_add_fro
 				if (errno == ENOENT)
 					return;
 				else
-					pg_fatal("error while checking for file existence \"%s.%s\" (\"%s\" to \"%s\"): %s",
+					pg_fatal("error while checking for file existence \"%s.%s\" (\"%s\" to \"%s\"): %m",
-							 map->nspname, map->relname, old_file, new_file,
+							 map->nspname, map->relname, old_file, new_file);
-							 strerror(errno));
 			}
 
 			/* If file is empty, just return */

src/bin/pg_upgrade/tablespace.c

@@ -84,8 +84,8 @@ get_tablespace_paths(void)
 							  os_info.old_tablespaces[tblnum]);
 			else
 				report_status(PG_FATAL,
-							  "could not stat tablespace directory \"%s\": %s",
+							  "could not stat tablespace directory \"%s\": %m",
-							  os_info.old_tablespaces[tblnum], strerror(errno));
+							  os_info.old_tablespaces[tblnum]);
 		}
 		if (!S_ISDIR(statBuf.st_mode))
 			report_status(PG_FATAL,

src/bin/pg_upgrade/version.c

@@ -113,8 +113,7 @@ check_for_data_types_usage(ClusterInfo *cluster,
 		{
 			found = true;
 			if (script == NULL && (script = fopen_priv(output_path, "w")) == NULL)
-				pg_fatal("could not open file \"%s\": %s", output_path,
+				pg_fatal("could not open file \"%s\": %m", output_path);
-						 strerror(errno));
 			if (!db_used)
 			{
 				fprintf(script, "In database: %s\n", active_db->db_name);
@@ -289,8 +288,7 @@ old_9_6_invalidate_hash_indexes(ClusterInfo *cluster, bool check_mode)
 			if (!check_mode)
 			{
 				if (script == NULL && (script = fopen_priv(output_path, "w")) == NULL)
-					pg_fatal("could not open file \"%s\": %s", output_path,
+					pg_fatal("could not open file \"%s\": %m", output_path);
-							 strerror(errno));
 				if (!db_used)
 				{
 					PQExpBufferData connectbuf;
@@ -423,8 +421,7 @@ report_extension_updates(ClusterInfo *cluster)
 		for (rowno = 0; rowno < ntups; rowno++)
 		{
 			if (script == NULL && (script = fopen_priv(output_path, "w")) == NULL)
-				pg_fatal("could not open file \"%s\": %s", output_path,
+				pg_fatal("could not open file \"%s\": %m", output_path);
-						 strerror(errno));
 			if (!db_used)
 			{
 				PQExpBufferData connectbuf;

src/common/psprintf.c

@@ -115,8 +115,8 @@ pvsnprintf(char *buf, size_t len, const char *fmt, va_list args)
 #ifndef FRONTEND
 		elog(ERROR, "vsnprintf failed: %m with format string \"%s\"", fmt);
 #else
-		fprintf(stderr, "vsnprintf failed: %s with format string \"%s\"\n",
+		fprintf(stderr, "vsnprintf failed: %m with format string \"%s\"\n",
-				strerror(errno), fmt);
+				fmt);
 		exit(EXIT_FAILURE);
 #endif
 	}

src/interfaces/ecpg/preproc/ecpg.c

@@ -216,8 +216,8 @@ main(int argc, char *const argv[])
 
 				if (base_yyout == NULL)
 				{
-					fprintf(stderr, _("%s: could not open file \"%s\": %s\n"),
+					fprintf(stderr, _("%s: could not open file \"%s\": %m\n"),
-							progname, output_filename, strerror(errno));
+							progname, output_filename);
 					output_filename = NULL;
 				}
 				else
@@ -331,8 +331,8 @@ main(int argc, char *const argv[])
 					base_yyout = fopen(output_filename, PG_BINARY_W);
 					if (base_yyout == NULL)
 					{
-						fprintf(stderr, _("%s: could not open file \"%s\": %s\n"),
+						fprintf(stderr, _("%s: could not open file \"%s\": %m\n"),
-								progname, output_filename, strerror(errno));
+								progname, output_filename);
 						free(output_filename);
 						output_filename = NULL;
 						free(input_filename);
@@ -342,8 +342,8 @@ main(int argc, char *const argv[])
 			}
 
 			if (base_yyin == NULL)
-				fprintf(stderr, _("%s: could not open file \"%s\": %s\n"),
+				fprintf(stderr, _("%s: could not open file \"%s\": %m\n"),
-						progname, argv[fnr], strerror(errno));
+						progname, argv[fnr]);
 			else
 			{
 				struct cursor *ptr;

src/port/path.c

@@ -772,8 +772,7 @@ make_absolute_path(const char *path)
 #ifndef FRONTEND
 				elog(ERROR, "could not get current working directory: %m");
 #else
-				fprintf(stderr, _("could not get current working directory: %s\n"),
+				fprintf(stderr, _("could not get current working directory: %m\n"));
-						strerror(errno));
 				return NULL;
 #endif
 			}

src/test/isolation/isolationtester.c

@@ -871,7 +871,7 @@ try_complete_step(TestSpec *testspec, PermutationStep *pstep, int flags)
 		{
 			if (errno == EINTR)
 				continue;
-			fprintf(stderr, "select failed: %s\n", strerror(errno));
+			fprintf(stderr, "select failed: %m\n");
 			exit(1);
 		}
 		else if (ret == 0)		/* select() timeout: check for lock wait */

src/test/modules/libpq_pipeline/libpq_pipeline.c

@@ -492,7 +492,7 @@ test_nosync(PGconn *conn)
 		tv.tv_usec = 0;
 		if (select(sock + 1, &input_mask, NULL, NULL, &tv) < 0)
 		{
-			fprintf(stderr, "select() failed: %s\n", strerror(errno));
+			fprintf(stderr, "select() failed: %m\n");
 			exit_nicely(conn);
 		}
 		if (FD_ISSET(sock, &input_mask) && PQconsumeInput(conn) != 1)
@@ -943,7 +943,7 @@ test_pipelined_insert(PGconn *conn, int n_rows)
 
 		if (select(sock + 1, &input_mask, &output_mask, NULL, NULL) < 0)
 		{
-			fprintf(stderr, "select() failed: %s\n", strerror(errno));
+			fprintf(stderr, "select() failed: %m\n");
 			exit_nicely(conn);
 		}
 

src/tools/ifaddrs/test_ifaddrs.c

@@ -66,6 +66,6 @@ main(int argc, char *argv[])
 #endif
 
 	if (pg_foreach_ifaddr(callback, NULL) < 0)
-		fprintf(stderr, "pg_foreach_ifaddr failed: %s\n", strerror(errno));
+		fprintf(stderr, "pg_foreach_ifaddr failed: %m\n");
 	return 0;
 }