pg_upgrade: Default new bindir to pg_upgrade location

Make the directory where the pg_upgrade binary resides the default for
new bindir, as running the pg_upgrade binary from where the new
cluster is installed is a very common scenario.  Setting this as the
defauly bindir for the new cluster will remove the need to provide it
explicitly via -B in many cases.

To support directories being missing from option parsing, extend the
directory check with a missingOk mode where the path must be filled at
a later point before being used.  Also move the exec_path check to
earlier in setup to make sure we know the new cluster bindir when we
scan for required executables.

This removes the exec_path from the OSInfo struct as it is not used
anywhere.

Author: Daniel Gustafsson <daniel@yesql.se>
Reviewed-by: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>
Discussion: https://www.postgresql.org/message-id/flat/9328.1552952117@sss.pgh.pa.us

doc/src/sgml/ref/pgupgrade.sgml

@@ -89,6 +89,7 @@
       <term><option>-B</option> <replaceable>bindir</replaceable></term>
       <term><option>--new-bindir=</option><replaceable>bindir</replaceable></term>
       <listitem><para>the new PostgreSQL executable directory;
+      default is the directory where <application>pg_upgrade</application> resides;
       environment variable <envar>PGBINNEW</envar></para></listitem>
      </varlistentry>
 

src/bin/pg_upgrade/option.c

@@ -23,7 +23,8 @@
 static void usage(void);
 static void check_required_directory(char **dirpath,
 									 const char *envVarName, bool useCwd,
-									 const char *cmdLineOption, const char *description);
+									 const char *cmdLineOption, const char *description,
+									 bool missingOk);
 #define FIX_DEFAULT_READ_ONLY "-c default_transaction_read_only=false"
 
 
@@ -251,15 +252,15 @@ parseCommandLine(int argc, char *argv[])
 
 	/* Get values from env if not already set */
 	check_required_directory(&old_cluster.bindir, "PGBINOLD", false,
-							 "-b", _("old cluster binaries reside"));
+							 "-b", _("old cluster binaries reside"), false);
 	check_required_directory(&new_cluster.bindir, "PGBINNEW", false,
-							 "-B", _("new cluster binaries reside"));
+							 "-B", _("new cluster binaries reside"), true);
 	check_required_directory(&old_cluster.pgdata, "PGDATAOLD", false,
-							 "-d", _("old cluster data resides"));
+							 "-d", _("old cluster data resides"), false);
 	check_required_directory(&new_cluster.pgdata, "PGDATANEW", false,
-							 "-D", _("new cluster data resides"));
+							 "-D", _("new cluster data resides"), false);
 	check_required_directory(&user_opts.socketdir, "PGSOCKETDIR", true,
-							 "-s", _("sockets will be created"));
+							 "-s", _("sockets will be created"), false);
 
 #ifdef WIN32
 
@@ -293,7 +294,8 @@ usage(void)
 	printf(_("  pg_upgrade [OPTION]...\n\n"));
 	printf(_("Options:\n"));
 	printf(_("  -b, --old-bindir=BINDIR       old cluster executable directory\n"));
-	printf(_("  -B, --new-bindir=BINDIR       new cluster executable directory\n"));
+	printf(_("  -B, --new-bindir=BINDIR       new cluster executable directory (default\n"
+			 "                                same directory as pg_upgrade)"));
 	printf(_("  -c, --check                   check clusters only, don't change any data\n"));
 	printf(_("  -d, --old-datadir=DATADIR     old cluster data directory\n"));
 	printf(_("  -D, --new-datadir=DATADIR     new cluster data directory\n"));
@@ -351,13 +353,15 @@ usage(void)
  *	useCwd		  - true if OK to default to CWD
  *	cmdLineOption - the command line option for this directory
  *	description   - a description of this directory option
+ *	missingOk	  - true if OK that both dirpath and envVarName are not existing
  *
  * We use the last two arguments to construct a meaningful error message if the
  * user hasn't provided the required directory name.
  */
 static void
 check_required_directory(char **dirpath, const char *envVarName, bool useCwd,
-						 const char *cmdLineOption, const char *description)
+						 const char *cmdLineOption, const char *description,
+						 bool missingOk)
 {
 	if (*dirpath == NULL || strlen(*dirpath) == 0)
 	{
@@ -373,6 +377,8 @@ check_required_directory(char **dirpath, const char *envVarName, bool useCwd,
 				pg_fatal("could not determine current directory\n");
 			*dirpath = pg_strdup(cwd);
 		}
+		else if (missingOk)
+			return;
 		else
 			pg_fatal("You must identify the directory where the %s.\n"
 					 "Please use the %s command-line option or the %s environment variable.\n",

src/bin/pg_upgrade/pg_upgrade.c

@@ -204,14 +204,29 @@ main(int argc, char **argv)
 static void
 setup(char *argv0, bool *live_check)
 {
-	char		exec_path[MAXPGPATH];	/* full path to my executable */
-
 	/*
 	 * make sure the user has a clean environment, otherwise, we may confuse
 	 * libpq when we connect to one (or both) of the servers.
 	 */
 	check_pghost_envvar();
 
+	/*
+	 * In case the user hasn't specified the directory for the new binaries
+	 * with -B, default to using the path of the currently executed pg_upgrade
+	 * binary.
+	 */
+	if (!new_cluster.bindir)
+	{
+		char		exec_path[MAXPGPATH];
+
+		if (find_my_exec(argv0, exec_path) < 0)
+			pg_fatal("%s: could not find own program executable\n", argv0);
+		/* Trim off program name and keep just path */
+		*last_dir_separator(exec_path) = '\0';
+		canonicalize_path(exec_path);
+		new_cluster.bindir = pg_strdup(exec_path);
+	}
+
 	verify_directories();
 
 	/* no postmasters should be running, except for a live check */
@@ -247,15 +262,6 @@ setup(char *argv0, bool *live_check)
 			pg_fatal("There seems to be a postmaster servicing the new cluster.\n"
 					 "Please shutdown that postmaster and try again.\n");
 	}
-
-	/* get path to pg_upgrade executable */
-	if (find_my_exec(argv0, exec_path) < 0)
-		pg_fatal("%s: could not find own program executable\n", argv0);
-
-	/* Trim off program name and keep just path */
-	*last_dir_separator(exec_path) = '\0';
-	canonicalize_path(exec_path);
-	os_info.exec_path = pg_strdup(exec_path);
 }
 
 

src/bin/pg_upgrade/pg_upgrade.h

@@ -314,7 +314,6 @@ typedef struct
 typedef struct
 {
 	const char *progname;		/* complete pathname for this program */
-	char	   *exec_path;		/* full path to my executable */
 	char	   *user;			/* username for clusters */
 	bool		user_specified; /* user specified on command-line */
 	char	  **old_tablespaces;	/* tablespaces */

src/bin/pg_upgrade/test.sh

@@ -220,7 +220,7 @@ PGDATA="$BASE_PGDATA"
 
 standard_initdb 'initdb'
 
-pg_upgrade $PG_UPGRADE_OPTS -d "${PGDATA}.old" -D "$PGDATA" -b "$oldbindir" -B "$bindir" -p "$PGPORT" -P "$PGPORT"
+pg_upgrade $PG_UPGRADE_OPTS -d "${PGDATA}.old" -D "$PGDATA" -b "$oldbindir" -p "$PGPORT" -P "$PGPORT"
 
 # make sure all directories and files have group permissions, on Unix hosts
 # Windows hosts don't support Unix-y permissions.

src/tools/msvc/vcregress.pl

@@ -604,7 +604,7 @@ sub upgradecheck
 	print "\nRunning pg_upgrade\n\n";
 	@args = (
 		'pg_upgrade', '-d', "$data.old", '-D', $data, '-b',
-		$bindir,      '-B', $bindir);
+		$bindir);
 	system(@args) == 0 or exit 1;
 	print "\nStarting new cluster\n\n";
 	@args = ('pg_ctl', '-l', "$logdir/postmaster2.log", 'start');