Bug#47684: vsnprintf broken in libc6 (powerppc)

[Daniel Jacobowitz <dan@debian.org>]

On Mon, Oct 18, 1999 at 01:14:04AM +0100, Nuno Oliveira wrote:
> Package: libc6
> Version: 2.1.2-5
> 
> I get SIGSEGVs at the vsnprintf call in the following code
> segment (this is from dump-0.4, on powerpc):
> 
> void
> #ifdef __STDC__
> msg(const char *fmt, ...)
> #else
> msg(fmt, va_alist)
>         char *fmt;
>         va_dcl
> #ifdef __STDC__
>         va_start(ap, fmt);
> #else
>         va_start(ap);
> #endif
>         (void) vfprintf(stderr, fmt, ap);
>         (void) fflush(stdout);
>         (void) fflush(stderr);
>         (void) vsnprintf(lastmsg, sizeof(lastmsg), fmt, ap);
>         va_end(ap);
> }
> 
> The call to vfprintf just before is ok. Using libc_debug I get:

> This is probably related to bug #22541.


No, it's not.  You're violating the usage of varargs. You need to call
va_end() again and va_start a second time between the two uses of ap.

Dan

/--------------------------------\  /--------------------------------\
|       Daniel Jacobowitz        |__|        SCS Class of 2002       |
|   Debian GNU/Linux Developer    __    Carnegie Mellon University   |
|         dan@debian.org         |  |       dmj+@andrew.cmu.edu      |
\--------------------------------/  \--------------------------------/