Re: [patch] Fixed occasional failure to load a custom shared library

[Jan Kratochvil <jan.kratochvil@redhat.com>]

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Hi Kevin,

I am now copyright assignment compliant (as Red Hat employee).

Could you please commit the updated patch?  Its ChangeLog entry:

2006-07-21  Jan Kratochvil  <jan.kratochvil@redhat.com>

	* solib.c (solib_open): Fixed NULL vs. "" refusal to load inferior
	shared libraries.


Thanks,
Jan


On Tue, 27 Jun 2006 03:00:51 +0200, Kevin Buettner wrote:
> On Thu, 22 Jun 2006 13:40:16 +0200
> Jan Kratochvil <lace@jankratochvil.net> wrote:
> 
> Index: solib.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/solib.c,v
> retrieving revision 1.84
> diff -u -p -r1.84 solib.c
> --- solib.c	25 Feb 2006 04:36:39 -0000	1.84
> +++ solib.c	22 Jun 2006 11:24:40 -0000
> @@ -146,13 +146,17 @@ solib_open (char *in_pathname, char **fo
>    int found_file = -1;
>    char *temp_pathname = NULL;
>    char *p = in_pathname;
> +  int solib_absolute_prefix_is_empty;
> +
> +  solib_absolute_prefix_is_empty = (!solib_absolute_prefix
> +                                    || !*solib_absolute_prefix);
> 
> I'd prefer to see this written as follows:
> 
> +  solib_absolute_prefix_is_empty = (solib_absolute_prefix == NULL
> +                                    || *solib_absolute_prefix == 0);
> 
> The rest of your patch looks reasonable.  (You forgot to include a
> ChangeLog entry though...)
> 
> Are you able to commit this yourself or do you need someone to commit
> it for you?
> 
> Thanks for the patch!
> 
> Kevin

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https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=146810

Bug is still present in 2006-07-21 GDB CVS. The segfault is just a consequence of earlier failure to properly load the custom shared library:
Error while mapping shared library sections:
libc++test4dl.so: Success.


Index: solib.c
===================================================================
RCS file: /cvs/src/src/gdb/solib.c,v
retrieving revision 1.84
diff -u -p -r1.84 solib.c
--- solib.c	25 Feb 2006 04:36:39 -0000	1.84
+++ solib.c	21 Jul 2006 18:27:49 -0000
@@ -146,13 +146,17 @@ solib_open (char *in_pathname, char **fo
   int found_file = -1;
   char *temp_pathname = NULL;
   char *p = in_pathname;
+  int solib_absolute_prefix_is_empty;
+
+  solib_absolute_prefix_is_empty = (solib_absolute_prefix == NULL
+                                    || *solib_absolute_prefix == 0);
 
   while (*p && !IS_DIR_SEPARATOR (*p))
     p++;
 
   if (*p)
     {
-      if (! IS_ABSOLUTE_PATH (in_pathname) || solib_absolute_prefix == NULL)
+      if (! IS_ABSOLUTE_PATH (in_pathname) || solib_absolute_prefix_is_empty)
         temp_pathname = in_pathname;
       else
 	{
@@ -208,14 +212,14 @@ solib_open (char *in_pathname, char **fo
 					   &temp_pathname);
 
   /* If not found, next search the inferior's $PATH environment variable. */
-  if (found_file < 0 && solib_absolute_prefix == NULL)
+  if (found_file < 0 && solib_absolute_prefix_is_empty)
     found_file = openp (get_in_environ (inferior_environ, "PATH"),
 			OPF_TRY_CWD_FIRST, in_pathname, O_RDONLY | O_BINARY, 0,
 			&temp_pathname);
 
   /* If not found, next search the inferior's $LD_LIBRARY_PATH 
      environment variable. */
-  if (found_file < 0 && solib_absolute_prefix == NULL)
+  if (found_file < 0 && solib_absolute_prefix_is_empty)
     found_file = openp (get_in_environ (inferior_environ, "LD_LIBRARY_PATH"),
 			OPF_TRY_CWD_FIRST, in_pathname, O_RDONLY | O_BINARY, 0,
 			&temp_pathname);