[Libguestfs] [PATCH libguestfs 2/5] guestfish: write --help to stdout, use gnulib's progname module

[Jim Meyering]

Richard W.M. Jones wrote:
> On Mon, Aug 24, 2009 at 01:51:18PM +0200, Jim Meyering wrote:
>> @@ -205,6 +202,11 @@ main (int argc, char *argv[])
>>        (argv[0][0] != '/' || strstr (argv[0], "/.libs/lt-") != NULL))
>>      guestfs_set_path (g, "appliance:" GUESTFS_DEFAULT_PATH);
>>
>> +  /* getopt_long uses argv[0], so give it the sanitized name, too.
>> +     But only temporarily.  */
>> +  char *argv0 = argv[0];
>> +  argv[0] = bad_cast (program_name);
>> +
>>    for (;;) {
>>      c = getopt_long (argc, argv, options, long_options, &option_index);
>>      if (c == -1) break;
>
>> @@ -325,6 +327,9 @@ main (int argc, char *argv[])
>>      }
>>    }
>>
>> +  /* Restore original value.  */
>> +  argv[0] = argv0;
>> +
>>    /* Inspector mode invalidates most of the other arguments. */
>>    if (inspector) {
>>      char cmd[1024];
>
> I'm maybe missing something, but why restore it?
>
> How about instead something like:
>
> char *real_argv0 = argv[0];
> argv[0] = bad_cast (program_name);
>
>  //...
>
> /* change the path-munging code to use real_argv0 */
>
>  //...
>
> /* don't bother restoring argv[0] */

Sure.  That works, too.
Here's the incremental:

diff --git a/fish/fish.c b/fish/fish.c
index baa1b6e..e799f86 100644
--- a/fish/fish.c
+++ b/fish/fish.c
@@ -203,7 +203,7 @@ main (int argc, char *argv[])

   /* getopt_long uses argv[0], so give it the sanitized name, too.
      But only temporarily.  */
-  char *argv0 = argv[0];
+  char *real_argv0 = argv[0];
   argv[0] = bad_cast (program_name);

   for (;;) {
@@ -328,9 +328,6 @@ main (int argc, char *argv[])
     }
   }

-  /* Restore original value.  */
-  argv[0] = argv0;
-
   /* Inspector mode invalidates most of the other arguments. */
   if (inspector) {
     char cmd[1024];
@@ -352,7 +349,7 @@ main (int argc, char *argv[])

     strcpy (cmd, "a=`virt-inspector");
     while (optind < argc) {
-      if (strlen (cmd) + strlen (argv[optind]) + strlen (argv[0]) + 60
+      if (strlen (cmd) + strlen (argv[optind]) + strlen (real_argv0) + 60
           >= sizeof cmd) {
         fprintf (stderr,
                  _("%s: virt-inspector command too long for fixed-size buffer\n"),
@@ -370,7 +367,7 @@ main (int argc, char *argv[])
     else
       strcat (cmd, " --fish");

-    sprintf (&cmd[strlen(cmd)], "` && %s $a", argv[0]);
+    sprintf (&cmd[strlen(cmd)], "` && %s $a", real_argv0);

     if (guestfs_get_verbose (g))
       strcat (cmd, " -v");