Use XLOG_CONTROL_FILE macro consistently for control file name.

The XLOG_CONTROL_FILE macro (defined in access/xlog_internal.h)
represents the control file name. While some parts of the codebase already
use this macro, others previously hardcoded the file name as a string.

This commit replaces those hardcoded strings with the macro,
ensuring consistent usage throughout the code. This makes future
maintenance easier and improves searchability, for example when
grepping for control file usage.

Author: Anton A. Melnikov <a.melnikov@postgrespro.ru>
Reviewed-by: Daniel Gustafsson <daniel@yesql.se>
Reviewed-by: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Reviewed-by: Masao Fujii <masao.fujii@gmail.com>
Discussion: https://postgr.es/m/0841ec77-47e5-452a-adb4-c6fa55d605fc@postgrespro.ru

src/backend/backup/basebackup.c

@@ -1349,7 +1349,7 @@ sendDir(bbsink *sink, const char *path, int basepathlen, bool sizeonly,
 		snprintf(pathbuf, sizeof(pathbuf), "%s/%s", path, de->d_name);
 
 		/* Skip pg_control here to back up it last */
-		if (strcmp(pathbuf, "./global/pg_control") == 0)
+		if (strcmp(pathbuf, "./" XLOG_CONTROL_FILE) == 0)
 			continue;
 
 		if (lstat(pathbuf, &statbuf) != 0)

src/backend/postmaster/postmaster.c

@@ -90,6 +90,7 @@
 #endif
 
 #include "access/xlog.h"
+#include "access/xlog_internal.h"
 #include "access/xlogrecovery.h"
 #include "common/file_perm.h"
 #include "common/pg_prng.h"
@@ -1516,7 +1517,7 @@ checkControlFile(void)
 	char		path[MAXPGPATH];
 	FILE	   *fp;
 
-	snprintf(path, sizeof(path), "%s/global/pg_control", DataDir);
+	snprintf(path, sizeof(path), "%s/%s", DataDir, XLOG_CONTROL_FILE);
 
 	fp = AllocateFile(path, PG_BINARY_R);
 	if (fp == NULL)

src/bin/pg_combinebackup/pg_combinebackup.c

@@ -24,6 +24,7 @@
 #include <linux/fs.h>
 #endif
 
+#include "access/xlog_internal.h"
 #include "backup_label.h"
 #include "common/checksum_helper.h"
 #include "common/controldata_utils.h"
@@ -300,7 +301,7 @@ main(int argc, char *argv[])
 		{
 			char	   *controlpath;
 
-			controlpath = psprintf("%s/%s", prior_backup_dirs[i], "global/pg_control");
+			controlpath = psprintf("%s/%s", prior_backup_dirs[i], XLOG_CONTROL_FILE);
 
 			pg_fatal("%s: manifest system identifier is %" PRIu64 ", but control file has %" PRIu64,
 					 controlpath,
@@ -614,7 +615,7 @@ check_control_files(int n_backups, char **backup_dirs)
 		bool		crc_ok;
 		char	   *controlpath;
 
-		controlpath = psprintf("%s/%s", backup_dirs[i], "global/pg_control");
+		controlpath = psprintf("%s/%s", backup_dirs[i], XLOG_CONTROL_FILE);
 		pg_log_debug("reading \"%s\"", controlpath);
 		control_file = get_controlfile_by_exact_path(controlpath, &crc_ok);
 

src/bin/pg_controldata/pg_controldata.c

@@ -1,7 +1,7 @@
 /*
  * pg_controldata
  *
- * reads the data from $PGDATA/global/pg_control
+ * reads the data from the control file located at $PGDATA/XLOG_CONTROL_FILE.
  *
  * copyright (c) Oliver Elphick <olly@lfix.co.uk>, 2001;
  * license: BSD

src/bin/pg_rewind/filemap.c

@@ -26,6 +26,7 @@
 #include <sys/stat.h>
 #include <unistd.h>
 
+#include "access/xlog_internal.h"
 #include "catalog/pg_tablespace_d.h"
 #include "common/file_utils.h"
 #include "common/hashfn_unstable.h"
@@ -704,7 +705,7 @@ decide_file_action(file_entry_t *entry)
 	 * Don't touch the control file. It is handled specially, after copying
 	 * all the other files.
 	 */
-	if (strcmp(path, "global/pg_control") == 0)
+	if (strcmp(path, XLOG_CONTROL_FILE) == 0)
 		return FILE_ACTION_NONE;
 
 	/* Skip macOS system files */

src/bin/pg_rewind/pg_rewind.c

@@ -328,7 +328,7 @@ main(int argc, char **argv)
 	 * need to make sure by themselves that the target cluster is in a clean
 	 * state.
 	 */
-	buffer = slurpFile(datadir_target, "global/pg_control", &size);
+	buffer = slurpFile(datadir_target, XLOG_CONTROL_FILE, &size);
 	digestControlFile(&ControlFile_target, buffer, size);
 	pg_free(buffer);
 
@@ -338,12 +338,12 @@ main(int argc, char **argv)
 	{
 		ensureCleanShutdown(argv[0]);
 
-		buffer = slurpFile(datadir_target, "global/pg_control", &size);
+		buffer = slurpFile(datadir_target, XLOG_CONTROL_FILE, &size);
 		digestControlFile(&ControlFile_target, buffer, size);
 		pg_free(buffer);
 	}
 
-	buffer = source->fetch_file(source, "global/pg_control", &size);
+	buffer = source->fetch_file(source, XLOG_CONTROL_FILE, &size);
 	digestControlFile(&ControlFile_source, buffer, size);
 	pg_free(buffer);
 
@@ -636,7 +636,7 @@ perform_rewind(filemap_t *filemap, rewind_source *source,
 	 * Fetch the control file from the source last. This ensures that the
 	 * minRecoveryPoint is up-to-date.
 	 */
-	buffer = source->fetch_file(source, "global/pg_control", &size);
+	buffer = source->fetch_file(source, XLOG_CONTROL_FILE, &size);
 	digestControlFile(&ControlFile_source_after, buffer, size);
 	pg_free(buffer);
 

src/bin/pg_upgrade/controldata.c

@@ -12,6 +12,7 @@
 #include <ctype.h>
 #include <limits.h>				/* for CHAR_MIN */
 
+#include "access/xlog_internal.h"
 #include "common/string.h"
 #include "pg_upgrade.h"
 
@@ -757,10 +758,10 @@ disable_old_cluster(transferMode transfer_mode)
 				new_path[MAXPGPATH];
 
 	/* rename pg_control so old server cannot be accidentally started */
-	prep_status("Adding \".old\" suffix to old global/pg_control");
+	prep_status("Adding \".old\" suffix to old " XLOG_CONTROL_FILE);
 
-	snprintf(old_path, sizeof(old_path), "%s/global/pg_control", old_cluster.pgdata);
-	snprintf(new_path, sizeof(new_path), "%s/global/pg_control.old", old_cluster.pgdata);
+	snprintf(old_path, sizeof(old_path), "%s/%s", old_cluster.pgdata, XLOG_CONTROL_FILE);
+	snprintf(new_path, sizeof(new_path), "%s/%s.old", old_cluster.pgdata, XLOG_CONTROL_FILE);
 	if (pg_mv_file(old_path, new_path) != 0)
 		pg_fatal("could not rename file \"%s\" to \"%s\": %m",
 				 old_path, new_path);
@@ -769,10 +770,10 @@ disable_old_cluster(transferMode transfer_mode)
 	if (transfer_mode == TRANSFER_MODE_LINK)
 		pg_log(PG_REPORT, "\n"
 			   "If you want to start the old cluster, you will need to remove\n"
-			   "the \".old\" suffix from %s/global/pg_control.old.\n"
+			   "the \".old\" suffix from %s/%s.old.\n"
 			   "Because \"link\" mode was used, the old cluster cannot be safely\n"
 			   "started once the new cluster has been started.",
-			   old_cluster.pgdata);
+			   old_cluster.pgdata, XLOG_CONTROL_FILE);
 	else if (transfer_mode == TRANSFER_MODE_SWAP)
 		pg_log(PG_REPORT, "\n"
 			   "Because \"swap\" mode was used, the old cluster can no longer be\n"

src/bin/pg_verifybackup/astreamer_verify.c

@@ -14,6 +14,7 @@
 
 #include "postgres_fe.h"
 
+#include "access/xlog_internal.h"
 #include "catalog/pg_control.h"
 #include "pg_verifybackup.h"
 
@@ -225,7 +226,7 @@ member_verify_header(astreamer *streamer, astreamer_member *member)
 		(!mystreamer->context->skip_checksums && should_verify_checksum(m));
 	mystreamer->verify_control_data =
 		mystreamer->context->manifest->version != 1 &&
-		!m->bad && strcmp(m->pathname, "global/pg_control") == 0;
+		!m->bad && strcmp(m->pathname, XLOG_CONTROL_FILE) == 0;
 
 	/* If we're going to verify the checksum, initial a checksum context. */
 	if (mystreamer->verify_checksum &&
@@ -370,7 +371,7 @@ member_verify_control_data(astreamer *streamer)
 	pg_crc32c	crc;
 
 	/* Should be here only for control file */
-	Assert(strcmp(mystreamer->mfile->pathname, "global/pg_control") == 0);
+	Assert(strcmp(mystreamer->mfile->pathname, XLOG_CONTROL_FILE) == 0);
 	Assert(mystreamer->verify_control_data);
 
 	/*

src/bin/pg_verifybackup/pg_verifybackup.c

@@ -18,6 +18,7 @@
 #include <sys/stat.h>
 #include <time.h>
 
+#include "access/xlog_internal.h"
 #include "common/logging.h"
 #include "common/parse_manifest.h"
 #include "fe_utils/simple_list.h"
@@ -730,7 +731,7 @@ verify_plain_backup_file(verifier_context *context, char *relpath,
 	 * version 1.
 	 */
 	if (context->manifest->version != 1 &&
-		strcmp(relpath, "global/pg_control") == 0)
+		strcmp(relpath, XLOG_CONTROL_FILE) == 0)
 		verify_control_file(fullpath, context->manifest->system_identifier);
 
 	/* Update statistics for progress report, if necessary */

src/common/controldata_utils.c

@@ -53,7 +53,7 @@ get_controlfile(const char *DataDir, bool *crc_ok_p)
 {
 	char		ControlFilePath[MAXPGPATH];
 
-	snprintf(ControlFilePath, MAXPGPATH, "%s/global/pg_control", DataDir);
+	snprintf(ControlFilePath, MAXPGPATH, "%s/%s", DataDir, XLOG_CONTROL_FILE);
 
 	return get_controlfile_by_exact_path(ControlFilePath, crc_ok_p);
 }