Kludge 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.

diff -up popt-1.13/popt.c.execfail popt-1.13/popt.c

--- popt-1.13/popt.c.execfail	2012-08-02 16:08:34.762315304 +0300

+++ popt-1.13/popt.c	2012-08-02 16:11:41.352683721 +0300

@@ -186,6 +186,7 @@ poptContext poptGetContext(const char *

     con->flags = flags;

     con->execs = NULL;

     con->numExecs = 0;

+    con->execFail = NULL;

     con->finalArgvAlloced = argc * 2;

     con->finalArgv = calloc( con->finalArgvAlloced, sizeof(*con->finalArgv) );

     con->execAbsolute = 1;

@@ -234,6 +235,7 @@ void poptResetContext(poptContext con)

     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++) {

@@ -468,6 +470,7 @@ if (_popt_debug)

 /*@-nullstate@*/

     rc = execvp(argv[0], (char *const *)argv);

 /*@=nullstate@*/

+    con->execFail = xstrdup(argv[0]);

 exit:

     if (argv) {

@@ -1194,11 +1197,19 @@ int poptAddItem(poptContext con, poptIte

 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)

diff -up popt-1.13/poptint.h.execfail popt-1.13/poptint.h

--- popt-1.13/poptint.h.execfail	2012-08-02 16:08:34.000000000 +0300

+++ popt-1.13/poptint.h	2012-08-02 16:12:35.796500122 +0300

@@ -78,6 +78,7 @@ struct poptContext_s {

 /*@owned@*/ /*@null@*/

     poptItem execs;

     int numExecs;

+    char * execFail;

 /*@only@*/ /*@null@*/

     const char ** finalArgv;

     int finalArgvCount;