[PING][PATCH] mtrace: Use a static buffer for printing [BZ #25947]

[Siddhesh Poyarekar via Libc-alpha <libc-alpha@sourceware.org>]

Ping!

On 7/22/21 6:54 PM, Siddhesh Poyarekar via Libc-alpha wrote:
> Use a static buffer for mtrace printing now that it no longer adds to
> default libc footprint.
> ---
>   malloc/mtrace-impl.c | 14 +++-----------
>   1 file changed, 3 insertions(+), 11 deletions(-)
> 
> diff --git a/malloc/mtrace-impl.c b/malloc/mtrace-impl.c
> index 0e10ab7f60..83008ca18f 100644
> --- a/malloc/mtrace-impl.c
> +++ b/malloc/mtrace-impl.c
> @@ -34,11 +34,8 @@
>   
>   #include <kernel-features.h>
>   
> -#define TRACE_BUFFER_SIZE 512
> -
>   static FILE *mallstream;
>   static const char mallenv[] = "MALLOC_TRACE";
> -static char *malloc_trace_buffer;
>   
>   static void
>   tr_where (const void *caller, Dl_info *info)
> @@ -184,16 +181,13 @@ do_mtrace (void)
>     mallfile = secure_getenv (mallenv);
>     if (mallfile != NULL)
>       {
> -      char *mtb = malloc (TRACE_BUFFER_SIZE);
> -      if (mtb == NULL)
> -        return;
> -
>         mallstream = fopen (mallfile != NULL ? mallfile : "/dev/null", "wce");
>         if (mallstream != NULL)
>           {
>             /* Be sure it doesn't malloc its buffer!  */
> -          malloc_trace_buffer = mtb;
> -          setvbuf (mallstream, malloc_trace_buffer, _IOFBF, TRACE_BUFFER_SIZE);
> +	  static char tracebuf [512];
> +
> +	  setvbuf (mallstream, tracebuf, _IOFBF, sizeof (tracebuf));
>             fprintf (mallstream, "= Start\n");
>             if (!added_atexit_handler)
>               {
> @@ -203,8 +197,6 @@ do_mtrace (void)
>               }
>   	  __malloc_debug_enable (MALLOC_MTRACE_HOOK);
>           }
> -      else
> -        free (mtb);
>       }
>   }
>   
>