Patch from Fedora to return something semi-meaningful on exec alias fail

[Robert Scheck]

Hello all,

attached is a patch by Panu Matilainen who provided a patch to Fedora to
return something semi-meaningful on exec alias fail. But as I am not a C
developer, I do not have any clue if this patch is good or bad. However it
is applied in Fedora already for some time and doesn't seem to cause issues
there.

May you please review that patch and - if suitable - apply it for the next
popt, release? Thanks!


Greetings,
  Robert

Patch by Panu Matilainen <pmati...@redhat.com> for popt <= 1.16 which kludges
poptBadOption() to return something semi-meaningful on exec alias fail:

- poptBadOption() is totally unaware of exec alias failures, and will return
  either the first argument or last option, giving wonderfully misleading error
  messages (#697435, #710267).
- Remember execvp() first argument on failure and return that from
  poptBadOption() if present to give the user a reasonable clue what exactly
  went wrong.

--- popt-1.16/popt.c                            2010-01-19 01:39:10.000000000 
+0100
+++ popt-1.16/popt.c.execfail                   2013-11-24 15:50:06.000000000 
+0100
@@ -192,6 +192,7 @@
     con->flags = flags;
     con->execs = NULL;
     con->numExecs = 0;
+    con->execFail = NULL;
     con->finalArgvAlloced = argc * 2;
     con->finalArgv = calloc( (size_t)con->finalArgvAlloced, 
sizeof(*con->finalArgv) );
     con->execAbsolute = 1;
@@ -236,6 +237,7 @@
     con->nextLeftover = 0;
     con->restLeftover = 0;
     con->doExec = NULL;
+    con->execFail = _free(con->execFail);
 
     if (con->finalArgv != NULL)
     for (i = 0; i < con->finalArgvCount; i++) {
@@ -564,6 +566,7 @@
 /*@-nullstate@*/
     rc = execvp(argv[0], (char *const *)argv);
 /*@=nullstate@*/
+    con->execFail = xstrdup(argv[0]);
 
 exit:
     if (argv) {
@@ -1697,11 +1700,19 @@
 const char * poptBadOption(poptContext con, unsigned int flags)
 {
     struct optionStackEntry * os = NULL;
+    const char *badOpt = NULL;
 
-    if (con != NULL)
-       os = (flags & POPT_BADOPTION_NOALIAS) ? con->optionStack : con->os;
+    if (con != NULL) {
+       /* Stupid hack to return something semi-meaningful from exec failure */
+       if (con->execFail) {
+           badOpt = con->execFail;
+       } else {
+           os = (flags & POPT_BADOPTION_NOALIAS) ? con->optionStack : con->os;
+           badOpt = os->argv[os->next - 1];
+       }
+    }
 
-    return (os != NULL && os->argv != NULL ? os->argv[os->next - 1] : NULL);
+    return badOpt;
 }
 
 const char * poptStrerror(const int error)
--- popt-1.16/poptint.h                         2010-01-19 01:39:10.000000000 
+0100
+++ popt-1.16/poptint.h.execfail                2013-11-24 15:50:38.000000000 
+0100
@@ -132,6 +132,7 @@
 /*@owned@*/ /*@null@*/
     poptItem execs;
     int numExecs;
+    char * execFail;
 /*@only@*/ /*@null@*/
     poptArgv finalArgv;
     int finalArgvCount;

pgppEDI8me8ZB.pgp
Description: PGP signature