Add a --socketdir option to pg_upgrade.

This allows control of the directory in which the postmaster sockets
are created for the temporary postmasters started by pg_upgrade.
The default location remains the current working directory, which is
typically fine, but if it is deeply nested then its pathname might
be too long to be a socket name.

In passing, clean up some messiness in pg_upgrade's option handling,
particularly the confusing and undocumented way that configuration-only
datadirs were handled.  And fix check_required_directory's substantially
under-baked cleanup of directory pathnames.

Daniel Gustafsson, reviewed by Hironobu Suzuki, some code cleanup by me

Discussion: https://postgr.es/m/E72DD5C3-2268-48A5-A907-ED4B34BEC223@yesql.se

doc/src/sgml/ref/pgupgrade.sgml

@@ -163,6 +163,14 @@
       </para></listitem>
      </varlistentry>
 
+     <varlistentry>
+      <term><option>-s</option> <replaceable>dir</replaceable></term>
+      <term><option>--socketdir=</option><replaceable>dir</replaceable></term>
+      <listitem><para>directory to use for postmaster sockets during upgrade;
+      default is current working directory; environment
+      variable <envar>PGSOCKETDIR</envar></para></listitem>
+     </varlistentry>
+
      <varlistentry>
       <term><option>-U</option> <replaceable>username</replaceable></term>
       <term><option>--username=</option><replaceable>username</replaceable></term>
@@ -709,11 +717,21 @@ psql --username=postgres --file=script.sql postgres
   <title>Notes</title>
 
   <para>
-   <application>pg_upgrade</application> does not support upgrading of databases
+   <application>pg_upgrade</application> creates various working files, such
-   containing table columns using these <type>reg*</type> OID-referencing system data types:
+   as schema dumps, in the current working directory.  For security, be sure
-   <type>regproc</type>, <type>regprocedure</type>, <type>regoper</type>,
+   that that directory is not readable or writable by any other users.
-   <type>regoperator</type>, <type>regconfig</type>, and
+  </para>
-   <type>regdictionary</type>.  (<type>regtype</type> can be upgraded.)
+
+  <para>
+   <application>pg_upgrade</application> launches short-lived postmasters in
+   the old and new data directories.  Temporary Unix socket files for
+   communication with these postmasters are, by default, made in the current
+   working directory.  In some situations the path name for the current
+   directory might be too long to be a valid socket name.  In that case you
+   can use the <option>-s</option> option to put the socket files in some
+   directory with a shorter path name.  For security, be sure that that
+   directory is not readable or writable by any other users.
+   (This is not relevant on Windows.)
   </para>
 
   <para>
@@ -732,6 +750,14 @@ psql --username=postgres --file=script.sql postgres
    insert dummy data, and upgrade that.
   </para>
 
+  <para>
+   <application>pg_upgrade</application> does not support upgrading of databases
+   containing table columns using these <type>reg*</type> OID-referencing system data types:
+   <type>regproc</type>, <type>regprocedure</type>, <type>regoper</type>,
+   <type>regoperator</type>, <type>regconfig</type>, and
+   <type>regdictionary</type>.  (<type>regtype</type> can be upgraded.)
+  </para>
+
   <para>
    If you are upgrading a pre-<productname>PostgreSQL</productname> 9.2 cluster
    that uses a configuration-file-only directory, you must pass the

src/bin/pg_upgrade/option.c

@@ -21,8 +21,9 @@
 
 
 static void usage(void);
-static void check_required_directory(char **dirpath, char **configpath,
+static void check_required_directory(char **dirpath,
-						 const char *envVarName, const char *cmdLineOption, const char *description);
+						 const char *envVarName, bool useCwd,
+						 const char *cmdLineOption, const char *description);
 #define FIX_DEFAULT_READ_ONLY "-c default_transaction_read_only=false"
 
 
@@ -52,6 +53,7 @@ parseCommandLine(int argc, char *argv[])
 		{"link", no_argument, NULL, 'k'},
 		{"retain", no_argument, NULL, 'r'},
 		{"jobs", required_argument, NULL, 'j'},
+		{"socketdir", required_argument, NULL, 's'},
 		{"verbose", no_argument, NULL, 'v'},
 		{"clone", no_argument, NULL, 1},
 
@@ -102,7 +104,7 @@ parseCommandLine(int argc, char *argv[])
 	if ((log_opts.internal = fopen_priv(INTERNAL_LOG_FILE, "a")) == NULL)
 		pg_fatal("could not write to log file \"%s\"\n", INTERNAL_LOG_FILE);
 
-	while ((option = getopt_long(argc, argv, "d:D:b:B:cj:ko:O:p:P:rU:v",
+	while ((option = getopt_long(argc, argv, "d:D:b:B:cj:ko:O:p:P:rs:U:v",
 								 long_options, &optindex)) != -1)
 	{
 		switch (option)
@@ -121,12 +123,10 @@ parseCommandLine(int argc, char *argv[])
 
 			case 'd':
 				old_cluster.pgdata = pg_strdup(optarg);
-				old_cluster.pgconfig = pg_strdup(optarg);
 				break;
 
 			case 'D':
 				new_cluster.pgdata = pg_strdup(optarg);
-				new_cluster.pgconfig = pg_strdup(optarg);
 				break;
 
 			case 'j':
@@ -188,6 +188,10 @@ parseCommandLine(int argc, char *argv[])
 				log_opts.retain = true;
 				break;
 
+			case 's':
+				user_opts.socketdir = pg_strdup(optarg);
+				break;
+
 			case 'U':
 				pg_free(os_info.user);
 				os_info.user = pg_strdup(optarg);
@@ -244,14 +248,16 @@ parseCommandLine(int argc, char *argv[])
 		pg_putenv("PGOPTIONS", FIX_DEFAULT_READ_ONLY);
 
 	/* Get values from env if not already set */
-	check_required_directory(&old_cluster.bindir, NULL, "PGBINOLD", "-b",
+	check_required_directory(&old_cluster.bindir, "PGBINOLD", false,
-							 _("old cluster binaries reside"));
+							 "-b", _("old cluster binaries reside"));
-	check_required_directory(&new_cluster.bindir, NULL, "PGBINNEW", "-B",
+	check_required_directory(&new_cluster.bindir, "PGBINNEW", false,
-							 _("new cluster binaries reside"));
+							 "-B", _("new cluster binaries reside"));
-	check_required_directory(&old_cluster.pgdata, &old_cluster.pgconfig,
+	check_required_directory(&old_cluster.pgdata, "PGDATAOLD", false,
-							 "PGDATAOLD", "-d", _("old cluster data resides"));
+							 "-d", _("old cluster data resides"));
-	check_required_directory(&new_cluster.pgdata, &new_cluster.pgconfig,
+	check_required_directory(&new_cluster.pgdata, "PGDATANEW", false,
-							 "PGDATANEW", "-D", _("new cluster data resides"));
+							 "-D", _("new cluster data resides"));
+	check_required_directory(&user_opts.socketdir, "PGSOCKETDIR", true,
+							 "-s", _("sockets will be created"));
 
 #ifdef WIN32
 
@@ -296,6 +302,7 @@ usage(void)
 	printf(_("  -p, --old-port=PORT           old cluster port number (default %d)\n"), old_cluster.port);
 	printf(_("  -P, --new-port=PORT           new cluster port number (default %d)\n"), new_cluster.port);
 	printf(_("  -r, --retain                  retain SQL and log files after success\n"));
+	printf(_("  -s, --socketdir=DIR           socket directory to use (default CWD)\n"));
 	printf(_("  -U, --username=NAME           cluster superuser (default \"%s\")\n"), os_info.user);
 	printf(_("  -v, --verbose                 enable verbose internal logging\n"));
 	printf(_("  -V, --version                 display version information, then exit\n"));
@@ -337,29 +344,32 @@ usage(void)
  * check_required_directory()
  *
  * Checks a directory option.
- *	dirpath		  - the directory name supplied on the command line
+ *	dirpath		  - the directory name supplied on the command line, or NULL
- *	configpath	  - optional configuration directory
  *	envVarName	  - the name of an environment variable to get if dirpath is NULL
- *	cmdLineOption - the command line option corresponds to this directory (-o, -O, -n, -N)
+ *	useCwd		  - true if OK to default to CWD
+ *	cmdLineOption - the command line option for this directory
  *	description   - a description of this directory option
  *
  * 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, char **configpath,
+check_required_directory(char **dirpath, const char *envVarName, bool useCwd,
-						 const char *envVarName, const char *cmdLineOption,
+						 const char *cmdLineOption, const char *description)
-						 const char *description)
 {
 	if (*dirpath == NULL || strlen(*dirpath) == 0)
 	{
 		const char *envVar;
 
 		if ((envVar = getenv(envVarName)) && strlen(envVar))
-		{
 			*dirpath = pg_strdup(envVar);
-			if (configpath)
+		else if (useCwd)
-				*configpath = pg_strdup(envVar);
+		{
+			char		cwd[MAXPGPATH];
+
+			if (!getcwd(cwd, MAXPGPATH))
+				pg_fatal("could not determine current directory\n");
+			*dirpath = pg_strdup(cwd);
 		}
 		else
 			pg_fatal("You must identify the directory where the %s.\n"
@@ -368,16 +378,10 @@ check_required_directory(char **dirpath, char **configpath,
 	}
 
 	/*
-	 * Trim off any trailing path separators because we construct paths by
+	 * Clean up the path, in particular trimming any trailing path separators,
-	 * appending to this path.
+	 * because we construct paths by appending to this path.
 	 */
-#ifndef WIN32
+	canonicalize_path(*dirpath);
-	if ((*dirpath)[strlen(*dirpath) - 1] == '/')
-#else
-	if ((*dirpath)[strlen(*dirpath) - 1] == '/' ||
-		(*dirpath)[strlen(*dirpath) - 1] == '\\')
-#endif
-		(*dirpath)[strlen(*dirpath) - 1] = 0;
 }
 
 /*
@@ -386,6 +390,10 @@ check_required_directory(char **dirpath, char **configpath,
  * If a configuration-only directory was specified, find the real data dir
  * by querying the running server.  This has limited checking because we
  * can't check for a running server because we can't find postmaster.pid.
+ *
+ * On entry, cluster->pgdata has been set from command line or env variable,
+ * but cluster->pgconfig isn't set.  We fill both variables with corrected
+ * values.
  */
 void
 adjust_data_dir(ClusterInfo *cluster)
@@ -396,6 +404,9 @@ adjust_data_dir(ClusterInfo *cluster)
 	FILE	   *fp,
 			   *output;
 
+	/* Initially assume config dir and data dir are the same */
+	cluster->pgconfig = pg_strdup(cluster->pgdata);
+
 	/* If there is no postgresql.conf, it can't be a config-only dir */
 	snprintf(filename, sizeof(filename), "%s/postgresql.conf", cluster->pgconfig);
 	if ((fp = fopen(filename, "r")) == NULL)
@@ -462,12 +473,7 @@ get_sock_dir(ClusterInfo *cluster, bool live_check)
 	if (GET_MAJOR_VERSION(cluster->major_version) >= 901)
 	{
 		if (!live_check)
-		{
+			cluster->sockdir = user_opts.socketdir;
-			/* Use the current directory for the socket */
-			cluster->sockdir = pg_malloc(MAXPGPATH);
-			if (!getcwd(cluster->sockdir, MAXPGPATH))
-				pg_fatal("could not determine current directory\n");
-		}
 		else
 		{
 			/*

src/bin/pg_upgrade/pg_upgrade.h

@@ -298,7 +298,8 @@ typedef struct
 	bool		check;			/* true -> ask user for permission to make
 								 * changes */
 	transferMode transfer_mode; /* copy files or link them? */
-	int			jobs;
+	int			jobs;			/* number of processes/threads to use */
+	char	   *socketdir;		/* directory to use for Unix sockets */
 } UserOpts;
 
 typedef struct
@@ -374,7 +375,7 @@ bool		pid_lock_file_exists(const char *datadir);
 /* file.c */
 
 void cloneFile(const char *src, const char *dst,
-		 const char *schemaName, const char *relName);
+		  const char *schemaName, const char *relName);
 void copyFile(const char *src, const char *dst,
 		 const char *schemaName, const char *relName);
 void linkFile(const char *src, const char *dst,