RE: [RFA] Fix memory leak in windows_xfer_shared_libraries

["Pierre Muller" <pierre.muller@ics-cnrs.unistra.fr>]

 Whoops, 
  I forgot to test my patch :(

  Once again, got bitten by a difference
in syntax between C and pascal...
  a semicolon was missing before the else keyword...


Sorry about that,

Pierre  



> -----Message d'origine-----
> De : gdb-patches-owner@sourceware.org [mailto:gdb-patches-
> owner@sourceware.org] De la part de Pierre Muller
> Envoyé : jeudi 13 décembre 2012 12:11
> À : gdb-patches@sourceware.org
> Objet : [RFA] Fix memory leak in windows_xfer_shared_libraries
> 
>   The current mechanism of getting the list of DLLs when command
> infl dll
> is given to gdb prompt,
> info_shared_library function in solib.c calls
>   windows_xfer_shared_libraries in windows-nat.c
> 
>   using target_read_stralloc, which calls target_read_alloc_1.
> 
>   That function reiterates calls to target_read_partial
> until the number of transferred bytes is zero...
> 
>   This results even if the buffer is large enough to contain all data at
> first
> call in a second call in which the same xml answer is computed again,
> and nothing is done, because the offset correspond to the end of the
> resulting
> string.
> 
>   The current code has a memory leak that is fixed by the patch below.
> 
>   I was also wondering if it would not be better to keep the obstack in
> between the two calls, but that would probably require some static
variable
> :(
> 

Fixed patch:

2012-12-13  Pierre Muller  <muller@sourceware.org>

	* windows-nat.c (windows_xfer_shared_libraries): Avoid
	memory leak when OFFSET >= LEN_AVAIL.

Index: windows-nat.c
===================================================================
RCS file: /cvs/src/src/gdb/windows-nat.c,v
retrieving revision 1.236
diff -u -p -r1.236 windows-nat.c
--- windows-nat.c	13 Nov 2012 09:46:10 -0000	1.236
+++ windows-nat.c	13 Dec 2012 10:54:18 -0000
@@ -2411,11 +2411,11 @@ windows_xfer_shared_libraries (struct ta
   buf = obstack_finish (&obstack);
   len_avail = strlen (buf);
   if (offset >= len_avail)
-    return 0;
-
-  if (len > len_avail - offset)
+    len= 0;
+  else if (len > len_avail - offset)
     len = len_avail - offset;
-  memcpy (readbuf, buf + offset, len);
+  if (len > 0)
+    memcpy (readbuf, buf + offset, len);
 
   obstack_free (&obstack, NULL);
   return len;