pg_upgrade: Use new routine to retrieve data of PG_VERSION

Unsurprisingly, this shaves code.  get_major_server_version() can be
replaced by the new routine added by cd0be131ba6f, with the contents of
PG_VERSION stored in an allocated buffer instead of a fixed-sized one.

Author: Michael Paquier <michael@paquier.xyz>
Reviewed-by: Masahiko Sawada <sawada.mshk@gmail.com>
Discussion: https://postgr.es/m/aOiirvWJzwdVCXph@paquier.xyz

3 files changed, 4 insertions, 43 deletions

diff --git a/src/bin/pg_upgrade/exec.c b/src/bin/pg_upgrade/exec.c
index 63f2815a7cd..c045633d0c2 100644
--- a/src/bin/pg_upgrade/exec.c
+++ b/src/bin/pg_upgrade/exec.c
@@ -12,6 +12,7 @@
 #include <fcntl.h>
 
 #include "common/string.h"
+#include "fe_utils/version.h"
 #include "pg_upgrade.h"
 
 static void check_data_dir(ClusterInfo *cluster);
@@ -343,8 +344,8 @@ check_data_dir(ClusterInfo *cluster)
 	const char *pg_data = cluster->pgdata;
 
 	/* get the cluster version */
-	cluster->major_version = get_major_server_version(cluster);
-
+	cluster->major_version = get_pg_version(cluster->pgdata,
+											&cluster->major_version_str);
 	check_single_dir(pg_data, "");
 	check_single_dir(pg_data, "base");
 	check_single_dir(pg_data, "global");
diff --git a/src/bin/pg_upgrade/pg_upgrade.h b/src/bin/pg_upgrade/pg_upgrade.h
index 0ef47be0dc1..e86336f4be9 100644
--- a/src/bin/pg_upgrade/pg_upgrade.h
+++ b/src/bin/pg_upgrade/pg_upgrade.h
@@ -298,7 +298,7 @@ typedef struct
 	char	   *sockdir;		/* directory for Unix Domain socket, if any */
 	unsigned short port;		/* port number where postmaster is waiting */
 	uint32		major_version;	/* PG_VERSION of cluster */
-	char		major_version_str[64];	/* string PG_VERSION of cluster */
+	char	   *major_version_str;	/* string PG_VERSION of cluster */
 	uint32		bin_version;	/* version returned from pg_ctl */
 	char	  **tablespaces;	/* tablespace directories */
 	int			num_tablespaces;
@@ -473,7 +473,6 @@ char	   *cluster_conn_opts(ClusterInfo *cluster);
 
 bool		start_postmaster(ClusterInfo *cluster, bool report_and_exit_on_error);
 void		stop_postmaster(bool in_atexit);
-uint32		get_major_server_version(ClusterInfo *cluster);
 void		check_pghost_envvar(void);
 
 
diff --git a/src/bin/pg_upgrade/server.c b/src/bin/pg_upgrade/server.c
index 7eb15bc7d5a..d51bee885b8 100644
--- a/src/bin/pg_upgrade/server.c
+++ b/src/bin/pg_upgrade/server.c
@@ -148,45 +148,6 @@ executeQueryOrDie(PGconn *conn, const char *fmt,...)
 }
 
 
-/*
- * get_major_server_version()
- *
- * gets the version (in unsigned int form) for the given datadir. Assumes
- * that datadir is an absolute path to a valid pgdata directory. The version
- * is retrieved by reading the PG_VERSION file.
- */
-uint32
-get_major_server_version(ClusterInfo *cluster)
-{
-	FILE	   *version_fd;
-	char		ver_filename[MAXPGPATH];
-	int			v1 = 0,
-				v2 = 0;
-
-	snprintf(ver_filename, sizeof(ver_filename), "%s/PG_VERSION",
-			 cluster->pgdata);
-	if ((version_fd = fopen(ver_filename, "r")) == NULL)
-		pg_fatal("could not open version file \"%s\": %m", ver_filename);
-
-	if (fscanf(version_fd, "%63s", cluster->major_version_str) == 0 ||
-		sscanf(cluster->major_version_str, "%d.%d", &v1, &v2) < 1)
-		pg_fatal("could not parse version file \"%s\"", ver_filename);
-
-	fclose(version_fd);
-
-	if (v1 < 10)
-	{
-		/* old style, e.g. 9.6.1 */
-		return v1 * 10000 + v2 * 100;
-	}
-	else
-	{
-		/* new style, e.g. 10.1 */
-		return v1 * 10000;
-	}
-}
-
-
 static void
 stop_postmaster_atexit(void)
 {