Re: [PATCH] Fix Werror=stringop-overflow in target.c

[Jakub Jelinek]

On Mon, Nov 20, 2017 at 02:58:49PM +0100, Martin Liška wrote:
> Hello.
> 
> This is fix of compilation error I see with 
> --enable-offload-targets=nvptx-none=. It's explained
> in very detail way here:
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83007#c1
> 
> Ready for trunk?
> Martin
> 
> libgomp/ChangeLog:
> 
> 2017-11-20  Martin Liska  <mli...@suse.cz>
> 
>       * target.c (gomp_target_init): Use proper string operation.
> ---
>  libgomp/target.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)

I've instead committed this version after bootstrapping/regtesting it on
x86_64-linux and i686-linux:

2017-11-22  Jakub Jelinek  <ja...@redhat.com>

        PR libgomp/83106
        * target.c (gomp_target_init): Compute lengths just once and
        use them in both malloc size and subsequent copying.

--- libgomp/target.c.jj 2017-10-28 09:02:06.000000000 +0200
+++ libgomp/target.c    2017-11-22 13:54:56.250444247 +0100
@@ -2656,20 +2656,24 @@ gomp_target_init (void)
     do
       {
        struct gomp_device_descr current_device;
+       size_t prefix_len, suffix_len, cur_len;
 
        next = strchr (cur, ',');
 
-       plugin_name = (char *) malloc (1 + (next ? next - cur : strlen (cur))
-                                      + strlen (prefix) + strlen (suffix));
+       prefix_len = strlen (prefix);
+       cur_len = next ? next - cur : strlen (cur);
+       suffix_len = strlen (suffix);
+
+       plugin_name = (char *) malloc (prefix_len + cur_len + suffix_len + 1);
        if (!plugin_name)
          {
            num_devices = 0;
            break;
          }
 
-       strcpy (plugin_name, prefix);
-       strncat (plugin_name, cur, next ? next - cur : strlen (cur));
-       strcat (plugin_name, suffix);
+       memcpy (plugin_name, prefix, prefix_len);
+       memcpy (plugin_name + prefix_len, cur, cur_len);
+       memcpy (plugin_name + prefix_len + cur_len, suffix, suffix_len + 1);
 
        if (gomp_load_plugin_for_device (&current_device, plugin_name))
          {


        Jakub