Move PG_TEMP_FILE* macros to file_utils.h.

Presently, frontend code that needs to use these macros must either
include storage/fd.h, which declares several frontend-unsafe
functions, or duplicate the macros.  This commit moves these macros
to common/file_utils.h, which is safe for both frontend and backend
code.  Consequently, we can also remove the duplicated macros in
pg_checksums and stop including storage/fd.h in pg_rewind.

Reviewed-by: Michael Paquier
Discussion: https://postgr.es/m/ZOP5qoUualu5xl2Z%40paquier.xyz

src/backend/backup/basebackup.c

@@ -25,6 +25,7 @@
 #include "commands/defrem.h"
 #include "common/compression.h"
 #include "common/file_perm.h"
+#include "common/file_utils.h"
 #include "lib/stringinfo.h"
 #include "miscadmin.h"
 #include "nodes/pg_list.h"
@@ -37,7 +38,6 @@
 #include "storage/bufpage.h"
 #include "storage/checksum.h"
 #include "storage/dsm_impl.h"
-#include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/reinit.h"
 #include "utils/builtins.h"

src/backend/postmaster/postmaster.c

@@ -94,6 +94,7 @@
 #include "access/xlogrecovery.h"
 #include "catalog/pg_control.h"
 #include "common/file_perm.h"
+#include "common/file_utils.h"
 #include "common/ip.h"
 #include "common/pg_prng.h"
 #include "common/string.h"

src/backend/storage/file/fileset.c

@@ -25,6 +25,7 @@
 
 #include "catalog/pg_tablespace.h"
 #include "commands/tablespace.h"
+#include "common/file_utils.h"
 #include "common/hashfn.h"
 #include "miscadmin.h"
 #include "storage/ipc.h"

src/bin/pg_checksums/pg_checksums.c

@@ -52,16 +52,6 @@ typedef enum
 	PG_MODE_ENABLE
 } PgChecksumMode;
 
-/*
- * Filename components.
- *
- * XXX: fd.h is not declared here as frontend side code is not able to
- * interact with the backend-side definitions for the various fsync
- * wrappers.
- */
-#define PG_TEMP_FILES_DIR "pgsql_tmp"
-#define PG_TEMP_FILE_PREFIX "pgsql_tmp"
-
 static PgChecksumMode mode = PG_MODE_CHECK;
 
 static const char *progname;

src/bin/pg_rewind/filemap.c

@@ -27,12 +27,12 @@
 #include <unistd.h>
 
 #include "catalog/pg_tablespace_d.h"
+#include "common/file_utils.h"
 #include "common/hashfn.h"
 #include "common/string.h"
 #include "datapagemap.h"
 #include "filemap.h"
 #include "pg_rewind.h"
-#include "storage/fd.h"
 
 /*
  * Define a hash table which we can use to store information about the files

src/include/common/file_utils.h

@@ -46,4 +46,8 @@ extern ssize_t pg_pwritev_with_retry(int fd,
 
 extern ssize_t pg_pwrite_zeros(int fd, size_t size, off_t offset);
 
+/* Filename components */
+#define PG_TEMP_FILES_DIR "pgsql_tmp"
+#define PG_TEMP_FILE_PREFIX "pgsql_tmp"
+
 #endif							/* FILE_UTILS_H */

src/include/storage/fd.h

@@ -195,8 +195,4 @@ extern int	durable_unlink(const char *fname, int elevel);
 extern void SyncDataDirectory(void);
 extern int	data_sync_elevel(int elevel);
 
-/* Filename components */
-#define PG_TEMP_FILES_DIR "pgsql_tmp"
-#define PG_TEMP_FILE_PREFIX "pgsql_tmp"
-
 #endif							/* FD_H */