Re: gEDA-dev: Stack corruption PCB bug in hid_parse_actions????

[Peter Clifton <pcjc2-at-NOSPAMcam_dot_ac_dot_uk>]

On Wed, 2006-09-06 at 17:48 +0100, Peter Clifton wrote:

> Looks like a nasty stack corruption, as whilst argv[0] moves its
> location by 2 bytes (and IIRC, its always this ammount), argv[0] still
> evaluates to the same string.. as if a portion of the stack has been
> shifted. (Cant have shifted all of it, as the function return appears
to
> be ok) (Evaluation of argv[0] as string not shown in output below)
> 
> And program output - from an instrumented version of PCB:

Since it might be useful to make sense of the output below, attached is
the patch which adds the instrumentation I used to produce the output
originally in my email.

Peter
Index: src/action.c
===================================================================
RCS file: /cvsroot/pcb/pcb/src/action.c,v
retrieving revision 1.90
diff -U3 -p -r1.90 action.c
--- src/action.c	18 Aug 2006 03:30:57 -0000	1.90
+++ src/action.c	6 Sep 2006 17:00:37 -0000
@@ -6402,6 +6402,8 @@ ActionExecuteFile (int argc, char **argv
     AFAIL (executefile);
 
   fname = argv[0];
+  printf( "fname is %s\n", fname );
+  printf( "2 argv[0]=%p, fname=%p\n", argv[0],fname );
 
   if ((fp = fopen (fname, "r")) == NULL)
     {
@@ -6409,8 +6411,10 @@ ActionExecuteFile (int argc, char **argv
       return 1;
     }
 
+  printf( "3 argv[0]=%p, fname=%p\n", argv[0],fname );
   while (fgets (line, sizeof (line), fp) != NULL)
     {
+    printf( "4 argv[0]=%p, fname=%p\n", argv[0],fname );
       n++;
       sp = line;
 
@@ -6431,6 +6435,9 @@ ActionExecuteFile (int argc, char **argv
 
       if (*sp && *sp != '#')
 	{
+    printf( "fname %p, is \"%s\"\n", fname, fname );
+    printf( "n is \"%i\"\n", n );
+    printf( "sp %p, is \"%s\"\n", sp, sp );
 	  Message ("%s : line %-3d : \"%s\"\n", fname, n, sp);
 	  hid_parse_actions (sp, 0);
 	}
Index: src/hid/common/actions.c
===================================================================
RCS file: /cvsroot/pcb/pcb/src/hid/common/actions.c,v
retrieving revision 1.8
diff -U3 -p -r1.8 actions.c
--- src/hid/common/actions.c	20 Apr 2006 03:23:07 -0000	1.8
+++ src/hid/common/actions.c	6 Sep 2006 17:00:37 -0000
@@ -227,6 +227,8 @@ hid_parse_actions (const char *rstr,
   char *sp, *aname, *sp2;
   int maybe_empty = 0;
 
+  printf( "hid_parse_actions: rstr %p, is \"%s\", function %p\n", rstr, rstr, function );
+
   if (function == NULL)
     function = hid_actionv;
 
@@ -258,6 +260,7 @@ another:
    * we didn't find a leading ( so invoke the action
    * with no parameters or event.
    */
+  printf( "hid_parse_actions: sp %p, is \"%s\", aname %p, is \"%s\" \n", sp,sp,aname, aname );
   if (!*sp)
     {
       if (function (aname, 0, 0))
@@ -270,6 +273,7 @@ another:
    * action 
    */
   *sp++ = 0;
+  printf( "hid_parse_actions: sp %p, is \"%s\", aname %p, is \"%s\" \n", sp,sp,aname, aname );
   while (1)
     {
       /* 
@@ -279,6 +283,7 @@ another:
       if (*sp == ')' && !maybe_empty)
 	{
 	  *sp++ = 0;
+  printf( "hid_parse_actions: sp %p, is \"%s\", aname %p, is \"%s\" \n", sp,sp,aname, aname );
 	  if (function (aname, num, list))
 	    return 1;
 	  goto another;


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