Add a \setenv command to psql.

This can be used to set (or unset) environment variables that will
affect programs called by psql (such as the PAGER), probably most
usefully in a .psqlrc file.

Andrew Dunstan, reviewed by Josh Kupershmidt.

diff --git a/doc/src/sgml/ref/psql-ref.sgml b/doc/src/sgml/ref/psql-ref.sgml
index 01f57c4eeb9febf6bfe8c9b82adf26fd711b35e6..f97929b1fc9f47ddc2591a91099bced828b708fc 100644 (file)
--- a/doc/src/sgml/ref/psql-ref.sgml
+++ b/doc/src/sgml/ref/psql-ref.sgml
@@ -2241,6 +2241,24 @@ lo_import 152801
       </varlistentry>
 
 
+      <varlistentry>
+        <term><literal>\setenv [ <replaceable class="parameter">name</replaceable> [ <replaceable class="parameter">value</replaceable> ] ]</literal></term>
+
+        <listitem>
+        <para>
+        Sets the environment variable <replaceable
+        class="parameter">name</replaceable> to <replaceable
+        class="parameter">value</replaceable>, or if the
+        <replaceable class="parameter">value</replaceable> is
+        not supplied, unsets the environment variable. Example:
+<programlisting>
+testdb=&gt; <userinput>\setenv PAGER less</userinput>
+testdb=&gt; <userinput>\setenv LESS -imx4F</userinput>
+</programlisting>
+        </para>
+        </listitem>
+      </varlistentry>
+
       <varlistentry>
         <term><literal>\sf[+] <replaceable class="parameter">function_description</> </literal></term>
 

diff --git a/src/bin/psql/command.c b/src/bin/psql/command.c
index f885c1d74fec6afd15b74d57d019690be71887e1..e5cf5ff68f46ab7dce57f060d565558ff19c218e 100644 (file)
--- a/src/bin/psql/command.c
+++ b/src/bin/psql/command.c
@@ -1110,6 +1110,51 @@ exec_command(const char *cmd,
        free(opt0);
    }
 
+
+   /* \setenv -- set environment command */
+   else if (strcmp(cmd, "setenv") == 0)
+   {
+       char       *envvar = psql_scan_slash_option(scan_state,
+                                                 OT_NORMAL, NULL, false);
+       char       *envval = psql_scan_slash_option(scan_state,
+                                                 OT_NORMAL, NULL, false);
+
+       if (!envvar)
+       {
+           psql_error("\\%s: missing required argument\n", cmd);
+           success = false;
+       }
+       else if (strchr(envvar,'=') != NULL)
+       {
+           psql_error("\\%s: environment variable name must not contain '='\n",
+                      cmd);
+           success = false;
+       }
+       else if (!envval)
+       {
+           /* No argument - unset the environment variable */
+           unsetenv(envvar);
+           success = true;
+       }
+       else
+       {
+           /* Set variable to the value of the next argument */
+           int         len = strlen(envvar) + strlen(envval) + 1;
+           char       *newval = pg_malloc(len + 1);
+
+           snprintf(newval, len+1, "%s=%s", envvar, envval);
+           putenv(newval);
+           success = true;
+           /*
+            * Do not free newval here, it will screw up the environment
+            * if you do. See putenv man page for details. That means we
+            * leak a bit of memory here, but not enough to worry about.
+            */
+       }
+       free(envvar);
+       free(envval);
+   }
+
    /* \sf -- show a function's source code */
    else if (strcmp(cmd, "sf") == 0 || strcmp(cmd, "sf+") == 0)
    {

diff --git a/src/bin/psql/help.c b/src/bin/psql/help.c
index 4649e944755a5edd5b53f3a8143e4d7656b3a345..13d8bf61d4f36dc591ef47f2b78e685d806a085e 100644 (file)
--- a/src/bin/psql/help.c
+++ b/src/bin/psql/help.c
@@ -158,7 +158,7 @@ slashUsage(unsigned short int pager)
 {
    FILE       *output;
 
-   output = PageOutput(93, pager);
+   output = PageOutput(94, pager);
 
    /* if you add/remove a line here, change the row count above */
 
@@ -257,6 +257,7 @@ slashUsage(unsigned short int pager)
 
    fprintf(output, _("Operating System\n"));
    fprintf(output, _("  \\cd [DIR]              change the current working directory\n"));
+   fprintf(output, _("  \\setenv NAME [VALUE]   set or unset environment variable\n"));
    fprintf(output, _("  \\timing [on|off]       toggle timing of commands (currently %s)\n"),
            ON(pset.timing));
    fprintf(output, _("  \\! [COMMAND]           execute command in shell or start interactive shell\n"));