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[RFA-v2] Fix other memory leak in solib_target_current_sos
- From: "Pierre Muller" <pierre dot muller at ics-cnrs dot unistra dot fr>
- To: "'Pedro Alves'" <palves at redhat dot com>
- Cc: <gdb-patches at sourceware dot org>
- Date: Fri, 14 Dec 2012 14:07:21 +0100
- Subject: [RFA-v2] Fix other memory leak in solib_target_current_sos
- References: <50c9b7e6.25f2440a.3810.3771SMTPIN_ADDED_BROKEN@mx.google.com> <50CA3784.2030706@redhat.com> <000301cdd9d0$0db345d0$2919d170$@muller@ics-cnrs.unistra.fr> <50CAF521.3040307@redhat.com> <000001cdd9e5$6868f6e0$393ae4a0$@muller@ics-cnrs.unistra.fr> <50CB0574.7040406@redhat.com>
> -----Message d'origine-----
> De?: gdb-patches-owner@sourceware.org [mailto:gdb-patches-
> owner@sourceware.org] De la part de Pedro Alves
> Envoyé?: vendredi 14 décembre 2012 11:55
> À?: Pierre Muller
> Cc?: gdb-patches@sourceware.org
> Objet?: Re: [RFA] Fix other memory leak in solib_target_current_sos
>
> On 12/14/2012 10:25 AM, Pierre Muller wrote:
>
> > I found another leak, down the same line,
> > solib_target_current_sos
> > calls target_read_stralloc
> > which as its name suggests allocates the result on the heap...
> > But that string was not freed in the current code...
> >
> > This patch fixes that leak.
>
> Thanks.
>
> > 2012-12-14 Pierre Muller <muller@sourceware.org>
> >
> > * solib-target.c (solib_target_current_sos): Remove 'const'
> > qualifier from type of library_document local variable to be
> > able to free it and avoid a memory leak.
> >
> > Index: src/gdb/solib-target.c
> > ===================================================================
> > RCS file: /cvs/src/src/gdb/solib-target.c,v
> > retrieving revision 1.24
> > diff -u -p -r1.24 solib-target.c
> > --- src/gdb/solib-target.c 4 Jan 2012 08:17:11 -0000 1.24
> > +++ src/gdb/solib-target.c 14 Dec 2012 10:17:58 -0000
> > @@ -246,7 +246,7 @@ static struct so_list *
> > solib_target_current_sos (void)
> > {
> > struct so_list *new_solib, *start = NULL, *last = NULL;
> > - const char *library_document;
> > + char *library_document;
> > VEC(lm_info_p) *library_list;
> > struct lm_info *info;
> > int ix;
> > @@ -261,7 +261,10 @@ solib_target_current_sos (void)
> > /* Parse the list. */
> > library_list = solib_target_parse_libraries (library_document);
> > if (library_list == NULL)
> > - return NULL;
> > + {
> > + xfree (library_document);
> > + return NULL;
> > + }
> >
> > /* Build a struct so_list for each entry on the list. */
> > for (ix = 0; VEC_iterate (lm_info_p, library_list, ix, info); ix++)
> > @@ -291,6 +294,9 @@ solib_target_current_sos (void)
> > /* Free the library list, but not its members. */
> > VEC_free (lm_info_p, library_list);
> >
> > + /* Also free allocated library_document string. */
> > + xfree (library_document);
> > +
> > return start;
> > }
> >
>
> Parsing XML, within solib_target_parse_libraries, may throw. Thus, a
> cleanup would be better:
>
> + old_chain = make_cleanup (xfree, library_document);
> library_list = solib_target_parse_libraries (library_document);
> + do_cleanups (old_chain);
Of course...
library_document isn't needed after that point anymore.
New version of the patch below.
Pierre
2012-12-14 Pierre Muller <muller@sourceware.org>
Pedro Alves <palves@redhat.com>
* solib-target.c (solib_target_current_sos): Remove 'const'
qualifier from type of library_document local variable to be
able to free it and avoid a memory leak.
Use cleanup chain to avoid leak even if exceptino is generated.
Index: solib-target.c
===================================================================
RCS file: /cvs/src/src/gdb/solib-target.c,v
retrieving revision 1.24
diff -u -p -r1.24 solib-target.c
--- solib-target.c 4 Jan 2012 08:17:11 -0000 1.24
+++ solib-target.c 14 Dec 2012 13:03:13 -0000
@@ -246,7 +246,8 @@ static struct so_list *
solib_target_current_sos (void)
{
struct so_list *new_solib, *start = NULL, *last = NULL;
- const char *library_document;
+ char *library_document;
+ struct cleanup *old_chain;
VEC(lm_info_p) *library_list;
struct lm_info *info;
int ix;
@@ -258,8 +259,15 @@ solib_target_current_sos (void)
if (library_document == NULL)
return NULL;
+ /* solib_target_parse_libraries may throw, so we use a cleanup. */
+ old_chain = make_cleanup (xfree, library_document);
+
/* Parse the list. */
library_list = solib_target_parse_libraries (library_document);
+
+ /* library_document string is not needed behind this point. */
+ do_cleanups (old_chain);
+
if (library_list == NULL)
return NULL;