Re: [PATCH] malloc: Simplify implementation of __malloc_assert

[Adhemerval Zanella Netto <adhemerval.zanella@linaro.org>]

On 21/07/22 07:34, Florian Weimer via Libc-alpha wrote:
> It is prudent not to run too much code after detecting heap
> corruption, and __fxprintf is really complex.  The line number
> and file name do not carry much information, so it is not included
> in the error message.  (__libc_message only supports %s formatting.)
> The function name and assertion should provide some context.
> 
> Tested on i686-linux-gnu and x86_64-linux-gnu.  Also emulated the
> __libc_message call using GDB, and it produced the expected output.
> 
> Thanks,
> Florian
> ---
>  malloc/malloc.c | 15 +++++----------
>  1 file changed, 5 insertions(+), 10 deletions(-)
> 
> diff --git a/malloc/malloc.c b/malloc/malloc.c
> index 12908b8f97..bd3c76ed31 100644
> --- a/malloc/malloc.c
> +++ b/malloc/malloc.c
> @@ -292,19 +292,14 @@
>  # define __assert_fail(assertion, file, line, function)			\
>  	 __malloc_assert(assertion, file, line, function)
>  
> -extern const char *__progname;
> -
> -static void
> +_Noreturn static void
>  __malloc_assert (const char *assertion, const char *file, unsigned int line,
>  		 const char *function)
>  {
> -  (void) __fxprintf (NULL, "%s%s%s:%u: %s%sAssertion `%s' failed.\n",
> -		     __progname, __progname[0] ? ": " : "",
> -		     file, line,
> -		     function ? function : "", function ? ": " : "",
> -		     assertion);
> -  fflush (stderr);
> -  abort ();
> +  __libc_message (do_abort, "\
> +Fatal glibc error: malloc assertion failure in %s: %s\n",
> +		  function, assertion);
> +  __builtin_unreachable ();
>  }
>  #endif
>  #endif
> 

Would be better to keep the the file and line information?