[PATCH] Fix bug #28794: ps segfaults when given empty format string

[Carl Fredrik Hammar]

        * utils/ps.c (main): Move format parsing to parse_opt() and pass
        state to parse_enum().
---
Hi,

This fixes ps so it does not segfault when given an empty format string.
The problem was that parse_enum() is given a NULL pointer instead of a
pointer to the parsing state, so I simply moved the parsing code into the
argp parsing function parse_opt() where the parsing state is available
and pass it to parse_enum().  It is only run when the argument parsing
is successful, just as before.

Regards,
  Fredrik

 utils/ps.c |   40 ++++++++++++++++++++++------------------
 1 files changed, 22 insertions(+), 18 deletions(-)

diff --git a/utils/ps.c b/utils/ps.c
index 6f20965..992b467 100644
--- a/utils/ps.c
+++ b/utils/ps.c
@@ -324,6 +324,28 @@ main(int argc, char *argv[])
          state->child_inputs[0] = &pids_argp_params;
          break;
 
+       case ARGP_KEY_SUCCESS:
+         /* Select an explicit format string if FMT_STRING is a format
+            name.  This is done here because parse_enum needs STATE.  */
+         {
+           const char *fmt_name (unsigned n)
+             {
+               return
+                 n >= (sizeof output_fmts / sizeof *output_fmts)
+                   ? 0
+                   : output_fmts[n].name;
+             }
+           int fmt_index = parse_enum (fmt_string, fmt_name,
+                                       "format type", 1, state);
+           if (fmt_index >= 0)
+             {
+               fmt_string = output_fmts[fmt_index].fmt;
+               if (sort_key_name == NULL)
+                 sort_key_name = output_fmts[fmt_index].sort_key;
+             }
+         }
+         break;
+
        default:
          return ARGP_ERR_UNKNOWN;
        }
@@ -343,24 +365,6 @@ main(int argc, char *argv[])
   /* Parse our command line.  This shouldn't ever return an error.  */
   argp_parse (&argp, argc, argv, 0, 0, 0);
 
-  /* Select an explicit format string if FMT_STRING is a format name.  */
-  {
-    const char *fmt_name (unsigned n)
-      {
-       return
-         n >= (sizeof output_fmts / sizeof *output_fmts)
-           ? 0
-           : output_fmts[n].name;
-      }
-    int fmt_index = parse_enum (fmt_string, fmt_name, "format type", 1, 0);
-    if (fmt_index >= 0)
-      {
-       fmt_string = output_fmts[fmt_index].fmt;
-       if (sort_key_name == NULL)
-         sort_key_name = output_fmts[fmt_index].sort_key;
-      }
-  }
-
   err = proc_stat_list_create(context, &procset);
   if (err)
     error(1, err, "proc_stat_list_create");
-- 
1.6.5