Add postmaster -C option to query configuration parameters, and have

pg_ctl use that to query the data directory for config-only installs.
This fixes awkward or impossible pg_ctl operation for config-only
installs.

diff --git a/doc/src/sgml/ref/postgres-ref.sgml b/doc/src/sgml/ref/postgres-ref.sgml
index b16bbdfa4b359f9911b3a2a28e66287871b5ee0a..3807f4090a87026c0f13479f47ea917d912188f6 100644 (file)
--- a/doc/src/sgml/ref/postgres-ref.sgml
+++ b/doc/src/sgml/ref/postgres-ref.sgml
@@ -140,6 +140,20 @@ PostgreSQL documentation
       </listitem>
      </varlistentry>
 
+     <varlistentry>
+      <term><option>-C <replaceable>name</replaceable></option></term>
+      <listitem>
+       <para>
+        Returns the value of a named run-time parameter, and exits.
+        (See the <option>-c</> option above for details.)  This can
+        be used on a running server, and returns values from
+        <filename>postgresql.conf</>, modified by any parameters
+        supplied in this invocation.  It does not reflect parameters
+        supplied when the cluster was started.
+       </para>
+      </listitem>
+     </varlistentry>
+
      <varlistentry>
       <term><option>-d <replaceable>debug-level</replaceable></option></term>
       <listitem>

diff --git a/src/backend/main/main.c b/src/backend/main/main.c
index 8d9cb9428df2e4300f57ac4e40982a0b346ed669..b14c7318ab23961d8b4c41444cba31854f837785 100644 (file)
--- a/src/backend/main/main.c
+++ b/src/backend/main/main.c
@@ -283,6 +283,7 @@ help(const char *progname)
 #endif
        printf(_("  -B NBUFFERS     number of shared buffers\n"));
        printf(_("  -c NAME=VALUE   set run-time parameter\n"));
+       printf(_("  -C NAME         return run-time parameter\n"));
        printf(_("  -d 1-5          debugging level\n"));
        printf(_("  -D DATADIR      database directory\n"));
        printf(_("  -e              use European date input format (DMY)\n"));

diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 0a84d97f517fa5e55b6220ebfc22fce3f1fa9f87..dd7493cf9dd997543b225c2f2eb886c751dd7ab0 100644 (file)
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -203,6 +203,8 @@ bool                enable_bonjour = false;
 char      *bonjour_name;
 bool           restart_after_crash = true;
 
+char           *output_config_variable = NULL;
+
 /* PIDs of special child processes; 0 when not running */
 static pid_t StartupPID = 0,
                        BgWriterPID = 0,
@@ -537,7 +539,7 @@ PostmasterMain(int argc, char *argv[])
         * tcop/postgres.c (the option sets should not conflict) and with the
         * common help() function in main/main.c.
         */
-       while ((opt = getopt(argc, argv, "A:B:bc:D:d:EeFf:h:ijk:lN:nOo:Pp:r:S:sTt:W:-:")) != -1)
+       while ((opt = getopt(argc, argv, "A:B:bc:C:D:d:EeFf:h:ijk:lN:nOo:Pp:r:S:sTt:W:-:")) != -1)
        {
                switch (opt)
                {
@@ -554,6 +556,10 @@ PostmasterMain(int argc, char *argv[])
                                IsBinaryUpgrade = true;
                                break;
 
+                       case 'C':
+                               output_config_variable = optarg;
+                               break;
+
                        case 'D':
                                userDoption = optarg;
                                break;
@@ -728,6 +734,13 @@ PostmasterMain(int argc, char *argv[])
        if (!SelectConfigFiles(userDoption, progname))
                ExitPostmaster(2);
 
+       if (output_config_variable != NULL)
+       {
+               /* permission is handled because the user is reading inside the data dir */
+               puts(GetConfigOption(output_config_variable, false, false));
+               ExitPostmaster(0);
+       }
+       
        /* Verify that DataDir looks reasonable */
        checkDataDir();
 

diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index c7eac71e91e4a27d5b2cad1a0106db472d5209ce..19d94b252c2d882e35d8ae1eac724de00aa58c59 100644 (file)
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -3170,7 +3170,7 @@ process_postgres_switches(int argc, char *argv[], GucContext ctx)
         * postmaster/postmaster.c (the option sets should not conflict) and with
         * the common help() function in main/main.c.
         */
-       while ((flag = getopt(argc, argv, "A:B:bc:D:d:EeFf:h:ijk:lN:nOo:Pp:r:S:sTt:v:W:-:")) != -1)
+       while ((flag = getopt(argc, argv, "A:B:bc:C:D:d:EeFf:h:ijk:lN:nOo:Pp:r:S:sTt:v:W:-:")) != -1)
        {
                switch (flag)
                {
@@ -3187,6 +3187,10 @@ process_postgres_switches(int argc, char *argv[], GucContext ctx)
                                IsBinaryUpgrade = true;
                                break;
 
+                       case 'C':
+                               /* ignored for consistency with the postmaster */
+                               break;
+
                        case 'D':
                                if (secure)
                                        userDoption = strdup(optarg);
@@ -3272,7 +3276,7 @@ process_postgres_switches(int argc, char *argv[], GucContext ctx)
                                break;
 
                        case 'T':
-                               /* ignored for consistency with postmaster */
+                               /* ignored for consistency with the postmaster */
                                break;
 
                        case 't':

diff --git a/src/bin/pg_ctl/pg_ctl.c b/src/bin/pg_ctl/pg_ctl.c
index 0dbdfe7312cbe9ccad67b26d2e857dd19066d1c7..e633d0c18fee85aac2e639f4d40128b72f0de2ad 100644 (file)
--- a/src/bin/pg_ctl/pg_ctl.c
+++ b/src/bin/pg_ctl/pg_ctl.c
@@ -81,6 +81,7 @@ static ShutdownMode shutdown_mode = SMART_MODE;
 static int     sig = SIGTERM;          /* default */
 static CtlCommand ctl_command = NO_COMMAND;
 static char *pg_data = NULL;
+static char *pg_config = NULL;
 static char *pgdata_opt = NULL;
 static char *post_opts = NULL;
 static const char *progname;
@@ -131,6 +132,7 @@ static void do_status(void);
 static void do_promote(void);
 static void do_kill(pgpid_t pid);
 static void print_msg(const char *msg);
+static void adjust_data_dir(void);
 
 #if defined(WIN32) || defined(__CYGWIN__)
 static bool pgwin32_IsInstalled(SC_HANDLE);
@@ -1265,10 +1267,10 @@ pgwin32_CommandLine(bool registration)
                strcat(cmdLine, "\"");
        }
 
-       if (pg_data)
+       if (pg_config)
        {
                strcat(cmdLine, " -D \"");
-               strcat(cmdLine, pg_data);
+               strcat(cmdLine, pg_config);
                strcat(cmdLine, "\"");
        }
 
@@ -1886,6 +1888,59 @@ set_starttype(char *starttypeopt)
 }
 #endif
 
+/*
+ * adjust_data_dir
+ *
+ * If a configuration-only directory was specified, find the real data dir.
+ */
+void
+adjust_data_dir(void)
+{
+       char            cmd[MAXPGPATH], filename[MAXPGPATH], *my_exec_path;
+       FILE       *fd;
+
+       /* If there is no postgresql.conf, it can't be a config-only dir */
+       snprintf(filename, sizeof(filename), "%s/postgresql.conf", pg_config);
+       if ((fd = fopen(filename, "r")) == NULL)
+               return;
+       fclose(fd);
+
+       /* If PG_VERSION exists, it can't be a config-only dir */
+       snprintf(filename, sizeof(filename), "%s/PG_VERSION", pg_config);
+       if ((fd = fopen(filename, "r")) != NULL)
+       {
+               fclose(fd);
+               return;
+       }
+
+       /* Must be a configuration directory, so find the data directory */
+
+       /* we use a private my_exec_path to avoid interfering with later uses */
+       if (exec_path == NULL)
+               my_exec_path = find_other_exec_or_die(argv0, "postgres", PG_BACKEND_VERSIONSTR);
+       else
+               my_exec_path = xstrdup(exec_path);
+
+       snprintf(cmd, MAXPGPATH, SYSTEMQUOTE "\"%s\" %s%s -C data_directory" SYSTEMQUOTE,
+                        my_exec_path, pgdata_opt ? pgdata_opt : "", post_opts ?
+                        post_opts : "");
+
+       fd = popen(cmd, "r");
+       if (fd == NULL || fgets(filename, sizeof(filename), fd) == NULL)
+       {
+               write_stderr(_("%s: cannot find the data directory using %s\n"), progname, my_exec_path);
+               exit(1);
+       }
+       pclose(fd);
+       free(my_exec_path);
+
+       if (strlen(filename) > 0 && filename[strlen(filename) - 1] == '\n')
+               filename[strlen(filename) - 1] = '\0';
+       free(pg_data);
+       pg_data = xstrdup(filename);
+       canonicalize_path(pg_data);
+}
+
 
 int
 main(int argc, char **argv)
@@ -2120,14 +2175,17 @@ main(int argc, char **argv)
        }
 
        /* Note we put any -D switch into the env var above */
-       pg_data = getenv("PGDATA");
-       if (pg_data)
+       pg_config = getenv("PGDATA");
+       if (pg_config)
        {
-               pg_data = xstrdup(pg_data);
-               canonicalize_path(pg_data);
+               pg_config = xstrdup(pg_config);
+               canonicalize_path(pg_config);
+               pg_data = xstrdup(pg_config);
        }
 
-       if (pg_data == NULL &&
+       adjust_data_dir();
+       
+       if (pg_config == NULL &&
                ctl_command != KILL_COMMAND && ctl_command != UNREGISTER_COMMAND)
        {
                write_stderr(_("%s: no database directory specified and environment variable PGDATA unset\n"),