Re: [PATCH] Replace potentially unsafe alloca with xmalloc/xfree in value_concat

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

On Fri, 14 Sep 2012 14:48:33 +0200, Siddhesh Poyarekar wrote:
> http://sourceware.org/ml/gdb-cvs/2012-09/msg00068.html
> 
> CVSROOT:	/cvs/src
> Module name:	src
> Changes by:	siddhesh@sourceware.org	2012-09-14 12:46:56
> 
> Modified files:
> 	gdb            : ChangeLog valarith.c 
> 
> Log message:
> 	* valarith.c (value_concat): Replace unsafe ALLOCA with
> 	XMALLOC/XFREE.
> 
> Patches:
> http://sourceware.org/cgi-bin/cvsweb.cgi/src/gdb/ChangeLog.diff?cvsroot=src&r1=1.14659&r2=1.14660
> http://sourceware.org/cgi-bin/cvsweb.cgi/src/gdb/valarith.c.diff?cvsroot=src&r1=1.105&r2=1.106

I understand it is not significant but:

In this case you could post just the first link as this patch itself has been
(in fact - one line change) already posted here before.

If you meant this as the patch post this is still not easily + offline
reviewable.  For a full commit post either post 'cvs diff' before you commit
it or wait half an hour for mirror into GIT and take it from GIT or use the
script of mine:
	http://git.jankratochvil.net/?p=nethome.git;a=blob_plain;f=bin/changelogget;hb=master
	->
	changelogget -n http://sourceware.org/ml/gdb-cvs/2012-09/msg00068.html

I do not know how other people do that, there are many various possibilities.


Thanks,
Jan


http://sourceware.org/ml/gdb-cvs/2012-09/msg00068.html

--- src/gdb/ChangeLog	2012/09/14 12:10:21	1.14659
+++ src/gdb/ChangeLog	2012/09/14 12:46:55	1.14660
@@ -1,3 +1,8 @@
+2012-09-14  Siddhesh Poyarekar  <siddhesh@redhat.com>
+
+	* valarith.c (value_concat): Replace unsafe ALLOCA with
+	XMALLOC/XFREE.
+
 2012-09-14  Pedro Alves  <palves@redhat.com>
 
 	* gdb.1 (SEE ALSO): Expand pointer to GDB's Texinfo manual.
--- src/gdb/valarith.c	2012/08/16 07:36:20	1.105
+++ src/gdb/valarith.c	2012/09/14 12:46:55	1.106
@@ -668,9 +668,12 @@
       if (TYPE_CODE (type2) == TYPE_CODE_STRING
 	  || TYPE_CODE (type2) == TYPE_CODE_CHAR)
 	{
+	  struct cleanup *back_to;
+
 	  count = longest_to_int (value_as_long (inval1));
 	  inval2len = TYPE_LENGTH (type2);
-	  ptr = (char *) alloca (count * inval2len);
+	  ptr = (char *) xmalloc (count * inval2len);
+	  back_to = make_cleanup (xfree, ptr);
 	  if (TYPE_CODE (type2) == TYPE_CODE_CHAR)
 	    {
 	      char_type = type2;
@@ -693,6 +696,7 @@
 		}
 	    }
 	  outval = value_string (ptr, count * inval2len, char_type);
+	  do_cleanups (back_to);
 	}
       else if (TYPE_CODE (type2) == TYPE_CODE_BOOL)
 	{
@@ -706,6 +710,8 @@
   else if (TYPE_CODE (type1) == TYPE_CODE_STRING
 	   || TYPE_CODE (type1) == TYPE_CODE_CHAR)
     {
+      struct cleanup *back_to;
+
       /* We have two character strings to concatenate.  */
       if (TYPE_CODE (type2) != TYPE_CODE_STRING
 	  && TYPE_CODE (type2) != TYPE_CODE_CHAR)
@@ -714,7 +720,8 @@
 	}
       inval1len = TYPE_LENGTH (type1);
       inval2len = TYPE_LENGTH (type2);
-      ptr = (char *) alloca (inval1len + inval2len);
+      ptr = (char *) xmalloc (inval1len + inval2len);
+      back_to = make_cleanup (xfree, ptr);
       if (TYPE_CODE (type1) == TYPE_CODE_CHAR)
 	{
 	  char_type = type1;
@@ -737,6 +744,7 @@
 	  memcpy (ptr + inval1len, value_contents (inval2), inval2len);
 	}
       outval = value_string (ptr, inval1len + inval2len, char_type);
+      do_cleanups (back_to);
     }
   else if (TYPE_CODE (type1) == TYPE_CODE_BOOL)
     {