fio_check_postmaster() refactoring

Author: kulaginm

src/catchup.c

@@ -133,7 +133,7 @@ catchup_preflight_checks(PGNodeInfo *source_node_info, PGconn *source_conn,
 	if (current.backup_mode != BACKUP_MODE_FULL)
 	{
 		pid_t   pid;
-		pid = fio_check_postmaster(dest_pgdata, FIO_LOCAL_HOST);
+		pid = fio_check_postmaster(FIO_LOCAL_HOST, dest_pgdata);
 		if (pid == 1) /* postmaster.pid is mangled */
 		{
 			char	pid_filename[MAXPGPATH];

src/pg_probackup.h

@@ -1236,7 +1236,6 @@ extern PageState *fio_get_checksum_map(const char *fullpath, uint32 checksum_ver
 extern datapagemap_t *fio_get_lsn_map(const char *fullpath, uint32 checksum_version,
 							int n_blocks, XLogRecPtr horizonLsn, BlockNumber segmentno,
 							fio_location location);
-extern pid_t fio_check_postmaster(const char *pgdata, fio_location location);
 
 extern int32 fio_decompress(void* dst, void const* src, size_t size, int compress_alg, char **errormsg);
 

src/restore.c

@@ -2160,7 +2160,7 @@ check_incremental_compatibility(const char *pgdata, uint64 system_identifier,
 	char    backup_label[MAXPGPATH];
 
 	/* check postmaster pid */
-	pid = fio_check_postmaster(pgdata, FIO_DB_HOST);
+	pid = fio_check_postmaster(FIO_DB_HOST, pgdata);
 
 	if (pid == 1) /* postmaster.pid is mangled */
 	{

src/utils/file.c

@@ -3206,37 +3206,43 @@ local_check_postmaster(const char *pgdata)
  * and check that process is running, if process is running, return its pid number.
  */
 pid_t
-fio_check_postmaster(const char *pgdata, fio_location location)
+fio_check_postmaster(fio_location location, const char *pgdata)
 {
 	if (fio_is_remote(location))
 	{
-		fio_header hdr;
-
-		hdr.cop = FIO_CHECK_POSTMASTER;
-		hdr.size = strlen(pgdata) + 1;
+		fio_header hdr = {
+			.cop = FIO_CHECK_POSTMASTER,
+			.handle = -1,
+			.size = strlen(pgdata) + 1,
+			.arg = 0,
+		};
 
 		IO_CHECK(fio_write_all(fio_stdout, &hdr, sizeof(hdr)), sizeof(hdr));
 		IO_CHECK(fio_write_all(fio_stdout, pgdata, hdr.size), hdr.size);
 
 		/* receive result */
 		IO_CHECK(fio_read_all(fio_stdin, &hdr, sizeof(hdr)), sizeof(hdr));
+		Assert(hdr.cop == FIO_CHECK_POSTMASTER);
+
 		return hdr.arg;
 	}
 	else
 		return local_check_postmaster(pgdata);
 }
 
 static void
-fio_check_postmaster_impl(int out, char *buf)
+fio_check_postmaster_impl(const char *pgdata, int out)
 {
-	fio_header  hdr;
-	pid_t       postmaster_pid;
-	char       *pgdata = (char*) buf;
+	fio_header hdr = {
+		.cop = FIO_CHECK_POSTMASTER,
+		.handle = -1,
+		.size = 0,
+		.arg = 0,
+	};
 
-	postmaster_pid = local_check_postmaster(pgdata);
+	hdr.arg = local_check_postmaster(pgdata);
 
 	/* send arrays of checksums to main process */
-	hdr.arg = postmaster_pid;
 	IO_CHECK(fio_write_all(out, &hdr, sizeof(hdr)), sizeof(hdr));
 }
 
@@ -3427,8 +3433,7 @@ fio_communicate(int in, int out)
 			fio_get_lsn_map_impl(out, buf);
 			break;
 		  case FIO_CHECK_POSTMASTER:
-			/* calculate crc32 for a file */
-			fio_check_postmaster_impl(out, buf);
+			fio_check_postmaster_impl(buf, out);
 			break;
 		  case FIO_DISCONNECT:
 			hdr.cop = FIO_DISCONNECTED;

src/utils/file.h

@@ -147,6 +147,7 @@ extern int     fio_access(fio_location location, const char* path, int mode);
 extern int     fio_stat(fio_location location, const char* path, struct stat* st, bool follow_symlinks);
 extern bool    fio_is_same_file(fio_location location, const char* filename1, const char* filename2, bool follow_symlink);
 extern ssize_t fio_readlink(fio_location location, const char *path, char *value, size_t valsiz);
+extern pid_t   fio_check_postmaster(fio_location location, const char *pgdata);
 
 /* gzFile-style functions */
 #ifdef HAVE_LIBZ