pg_upgrade: prevent check on live cluster from generating error

Previously an inaccurate but harmless error was generated when running
--check on a live server before reporting the servers as compatible.
The fix is to split error reporting and exit control in the exec_prog()
API.

Reported-by: Daniel Westermann

Backpatch-through: 10

src/bin/pg_upgrade/dump.c

@@ -23,7 +23,7 @@ generate_old_dump(void)
 	prep_status("Creating dump of global objects");
 
 	/* run new pg_dumpall binary for globals */
-	exec_prog(UTILITY_LOG_FILE, NULL, true,
+	exec_prog(UTILITY_LOG_FILE, NULL, true, true,
 			  "\"%s/pg_dumpall\" %s --globals-only --quote-all-identifiers "
 			  "--binary-upgrade %s -f %s",
 			  new_cluster.bindir, cluster_conn_opts(&old_cluster),

src/bin/pg_upgrade/exec.c

@@ -71,16 +71,14 @@ get_bin_version(ClusterInfo *cluster)
  * and attempts to execute that command.  If the command executes
  * successfully, exec_prog() returns true.
  *
- * If the command fails, an error message is saved to the specified log_file.
- * If throw_error is true, this raises a PG_FATAL error and pg_upgrade
- * terminates; otherwise it is just reported as PG_REPORT and exec_prog()
- * returns false.
+ * If the command fails, an error message is optionally written to the specified
+ * log_file, and the program optionally exits.
  *
  * The code requires it be called first from the primary thread on Windows.
  */
 bool
 exec_prog(const char *log_file, const char *opt_log_file,
-		  bool throw_error, const char *fmt,...)
+		  bool report_error, bool exit_on_error, const char *fmt,...)
 {
 	int			result = 0;
 	int			written;
@@ -173,7 +171,7 @@ exec_prog(const char *log_file, const char *opt_log_file,
 #endif
 		result = system(cmd);
 
-	if (result != 0)
+	if (result != 0 && report_error)
 	{
 		/* we might be in on a progress status line, so go to the next line */
 		report_status(PG_REPORT, "\n*failure*");
@@ -181,12 +179,12 @@ exec_prog(const char *log_file, const char *opt_log_file,
 
 		pg_log(PG_VERBOSE, "There were problems executing \"%s\"\n", cmd);
 		if (opt_log_file)
-			pg_log(throw_error ? PG_FATAL : PG_REPORT,
+			pg_log(exit_on_error ? PG_FATAL : PG_REPORT,
 				   "Consult the last few lines of \"%s\" or \"%s\" for\n"
 				   "the probable cause of the failure.\n",
 				   log_file, opt_log_file);
 		else
-			pg_log(throw_error ? PG_FATAL : PG_REPORT,
+			pg_log(exit_on_error ? PG_FATAL : PG_REPORT,
 				   "Consult the last few lines of \"%s\" for\n"
 				   "the probable cause of the failure.\n",
 				   log_file);

src/bin/pg_upgrade/parallel.c

@@ -78,8 +78,8 @@ parallel_exec_prog(const char *log_file, const char *opt_log_file,
 	va_end(args);
 
 	if (user_opts.jobs <= 1)
-		/* throw_error must be true to allow jobs */
-		exec_prog(log_file, opt_log_file, true, "%s", cmd);
+		/* exit_on_error must be true to allow jobs */
+		exec_prog(log_file, opt_log_file, true, true, "%s", cmd);
 	else
 	{
 		/* parallel */
@@ -122,7 +122,7 @@ parallel_exec_prog(const char *log_file, const char *opt_log_file,
 		child = fork();
 		if (child == 0)
 			/* use _exit to skip atexit() functions */
-			_exit(!exec_prog(log_file, opt_log_file, true, "%s", cmd));
+			_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\n", strerror(errno));
@@ -160,7 +160,7 @@ win32_exec_prog(exec_thread_arg *args)
 {
 	int			ret;
 
-	ret = !exec_prog(args->log_file, args->opt_log_file, true, "%s", args->cmd);
+	ret = !exec_prog(args->log_file, args->opt_log_file, true, true, "%s", args->cmd);
 
 	/* terminates thread */
 	return ret;
@@ -187,7 +187,6 @@ parallel_transfer_all_new_dbs(DbInfoArr *old_db_arr, DbInfoArr *new_db_arr,
 #endif
 
 	if (user_opts.jobs <= 1)
-		/* throw_error must be true to allow jobs */
 		transfer_all_new_dbs(old_db_arr, new_db_arr, old_pgdata, new_pgdata, NULL);
 	else
 	{

src/bin/pg_upgrade/pg_upgrade.c

@@ -149,14 +149,14 @@ main(int argc, char **argv)
 	 * because there is no need to have the schema load use new oids.
 	 */
 	prep_status("Setting next OID for new cluster");
-	exec_prog(UTILITY_LOG_FILE, NULL, true,
+	exec_prog(UTILITY_LOG_FILE, NULL, true, true,
 			  "\"%s/pg_resetwal\" -o %u \"%s\"",
 			  new_cluster.bindir, old_cluster.controldata.chkpnt_nxtoid,
 			  new_cluster.pgdata);
 	check_ok();
 
 	prep_status("Sync data directory to disk");
-	exec_prog(UTILITY_LOG_FILE, NULL, true,
+	exec_prog(UTILITY_LOG_FILE, NULL, true, true,
 			  "\"%s/initdb\" --sync-only \"%s\"", new_cluster.bindir,
 			  new_cluster.pgdata);
 	check_ok();
@@ -249,7 +249,7 @@ prepare_new_cluster(void)
 	 * --analyze so autovacuum doesn't update statistics later
 	 */
 	prep_status("Analyzing all rows in the new cluster");
-	exec_prog(UTILITY_LOG_FILE, NULL, true,
+	exec_prog(UTILITY_LOG_FILE, NULL, true, true,
 			  "\"%s/vacuumdb\" %s --all --analyze %s",
 			  new_cluster.bindir, cluster_conn_opts(&new_cluster),
 			  log_opts.verbose ? "--verbose" : "");
@@ -262,7 +262,7 @@ prepare_new_cluster(void)
 	 * counter later.
 	 */
 	prep_status("Freezing all rows in the new cluster");
-	exec_prog(UTILITY_LOG_FILE, NULL, true,
+	exec_prog(UTILITY_LOG_FILE, NULL, true, true,
 			  "\"%s/vacuumdb\" %s --all --freeze %s",
 			  new_cluster.bindir, cluster_conn_opts(&new_cluster),
 			  log_opts.verbose ? "--verbose" : "");
@@ -289,7 +289,7 @@ prepare_new_databases(void)
 	 * support functions in template1 but pg_dumpall creates database using
 	 * the template0 template.
 	 */
-	exec_prog(UTILITY_LOG_FILE, NULL, true,
+	exec_prog(UTILITY_LOG_FILE, NULL, true, true,
 			  "\"%s/psql\" " EXEC_PSQL_ARGS " %s -f \"%s\"",
 			  new_cluster.bindir, cluster_conn_opts(&new_cluster),
 			  GLOBALS_DUMP_FILE);
@@ -392,7 +392,7 @@ copy_subdir_files(const char *old_subdir, const char *new_subdir)
 
 	prep_status("Copying old %s to new server", old_subdir);
 
-	exec_prog(UTILITY_LOG_FILE, NULL, true,
+	exec_prog(UTILITY_LOG_FILE, NULL, true, true,
 #ifndef WIN32
 			  "cp -Rf \"%s\" \"%s\"",
 #else
@@ -418,16 +418,16 @@ copy_xact_xlog_xid(void)
 
 	/* set the next transaction id and epoch of the new cluster */
 	prep_status("Setting next transaction ID and epoch for new cluster");
-	exec_prog(UTILITY_LOG_FILE, NULL, true,
+	exec_prog(UTILITY_LOG_FILE, NULL, true, true,
 			  "\"%s/pg_resetwal\" -f -x %u \"%s\"",
 			  new_cluster.bindir, old_cluster.controldata.chkpnt_nxtxid,
 			  new_cluster.pgdata);
-	exec_prog(UTILITY_LOG_FILE, NULL, true,
+	exec_prog(UTILITY_LOG_FILE, NULL, true, true,
 			  "\"%s/pg_resetwal\" -f -e %u \"%s\"",
 			  new_cluster.bindir, old_cluster.controldata.chkpnt_nxtepoch,
 			  new_cluster.pgdata);
 	/* must reset commit timestamp limits also */
-	exec_prog(UTILITY_LOG_FILE, NULL, true,
+	exec_prog(UTILITY_LOG_FILE, NULL, true, true,
 			  "\"%s/pg_resetwal\" -f -c %u,%u \"%s\"",
 			  new_cluster.bindir,
 			  old_cluster.controldata.chkpnt_nxtxid,
@@ -453,7 +453,7 @@ copy_xact_xlog_xid(void)
 		 * we preserve all files and contents, so we must preserve both "next"
 		 * counters here and the oldest multi present on system.
 		 */
-		exec_prog(UTILITY_LOG_FILE, NULL, true,
+		exec_prog(UTILITY_LOG_FILE, NULL, true, true,
 				  "\"%s/pg_resetwal\" -O %u -m %u,%u \"%s\"",
 				  new_cluster.bindir,
 				  old_cluster.controldata.chkpnt_nxtmxoff,
@@ -481,7 +481,7 @@ copy_xact_xlog_xid(void)
 		 * might end up wrapped around (i.e. 0) if the old cluster had
 		 * next=MaxMultiXactId, but multixact.c can cope with that just fine.
 		 */
-		exec_prog(UTILITY_LOG_FILE, NULL, true,
+		exec_prog(UTILITY_LOG_FILE, NULL, true, true,
 				  "\"%s/pg_resetwal\" -m %u,%u \"%s\"",
 				  new_cluster.bindir,
 				  old_cluster.controldata.chkpnt_nxtmulti + 1,
@@ -492,7 +492,7 @@ copy_xact_xlog_xid(void)
 
 	/* now reset the wal archives in the new cluster */
 	prep_status("Resetting WAL archives");
-	exec_prog(UTILITY_LOG_FILE, NULL, true,
+	exec_prog(UTILITY_LOG_FILE, NULL, true, true,
 	/* use timeline 1 to match controldata and no WAL history file */
 			  "\"%s/pg_resetwal\" -l 00000001%s \"%s\"", new_cluster.bindir,
 			  old_cluster.controldata.nextxlogfile + 8,

src/bin/pg_upgrade/pg_upgrade.h

@@ -360,7 +360,7 @@ void		generate_old_dump(void);
 #define EXEC_PSQL_ARGS "--echo-queries --set ON_ERROR_STOP=on --no-psqlrc --dbname=template1"
 
 bool exec_prog(const char *log_file, const char *opt_log_file,
-		  bool throw_error, const char *fmt,...) pg_attribute_printf(4, 5);
+		  bool report_error, bool exit_on_error, const char *fmt,...) pg_attribute_printf(5, 6);
 void		verify_directories(void);
 bool		pid_lock_file_exists(const char *datadir);
 
@@ -416,8 +416,8 @@ PGresult   *executeQueryOrDie(PGconn *conn, const char *fmt,...) pg_attribute_pr
 
 char	   *cluster_conn_opts(ClusterInfo *cluster);
 
-bool		start_postmaster(ClusterInfo *cluster, bool throw_error);
-void		stop_postmaster(bool fast);
+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);
 

src/bin/pg_upgrade/server.c

@@ -191,7 +191,7 @@ stop_postmaster_atexit(void)
 
 
 bool
-start_postmaster(ClusterInfo *cluster, bool throw_error)
+start_postmaster(ClusterInfo *cluster, bool report_and_exit_on_error)
 {
 	char		cmd[MAXPGPATH * 4 + 1000];
 	PGconn	   *conn;
@@ -257,11 +257,11 @@ start_postmaster(ClusterInfo *cluster, bool throw_error)
 							  (strcmp(SERVER_LOG_FILE,
 									  SERVER_START_LOG_FILE) != 0) ?
 							  SERVER_LOG_FILE : NULL,
-							  false,
+							  report_and_exit_on_error, false,
 							  "%s", cmd);
 
 	/* Did it fail and we are just testing if the server could be started? */
-	if (!pg_ctl_return && !throw_error)
+	if (!pg_ctl_return && !report_and_exit_on_error)
 		return false;
 
 	/*
@@ -305,9 +305,9 @@ start_postmaster(ClusterInfo *cluster, bool throw_error)
 	PQfinish(conn);
 
 	/*
-	 * If pg_ctl failed, and the connection didn't fail, and throw_error is
-	 * enabled, fail now.  This could happen if the server was already
-	 * running.
+	 * If pg_ctl failed, and the connection didn't fail, and
+	 * report_and_exit_on_error is enabled, fail now.  This
+	 * could happen if the server was already running.
 	 */
 	if (!pg_ctl_return)
 	{
@@ -322,7 +322,7 @@ start_postmaster(ClusterInfo *cluster, bool throw_error)
 
 
 void
-stop_postmaster(bool fast)
+stop_postmaster(bool in_atexit)
 {
 	ClusterInfo *cluster;
 
@@ -333,11 +333,11 @@ stop_postmaster(bool fast)
 	else
 		return;					/* no cluster running */
 
-	exec_prog(SERVER_STOP_LOG_FILE, NULL, !fast,
+	exec_prog(SERVER_STOP_LOG_FILE, NULL, !in_atexit, !in_atexit,
 			  "\"%s/pg_ctl\" -w -D \"%s\" -o \"%s\" %s stop",
 			  cluster->bindir, cluster->pgconfig,
 			  cluster->pgopts ? cluster->pgopts : "",
-			  fast ? "-m fast" : "-m smart");
+			  in_atexit ? "-m fast" : "-m smart");
 
 	os_info.running_cluster = NULL;
 }