Brice Goglin <brice.gog...@inria.fr> writes:
> When the program name is very long, qemu-user may truncate it in
> /proc/self/stat. However the truncation must keep the ending ") "
> to conform to the proc manpage which says:
> (2) comm %s
> The filename of the executable, in parentheses. This
> is visible whether or not the executable is swapped
> out.
>
> To reproduce:
> $ ln -s /bin/cat <filenamewithmorethan128chars>
> $ qemu-x86_64 ./<filenamewithmorethan128chars> /proc/self/stat
>
> Before the patch, you get:
> 1134631 (<filenametruncated>0 0 0 0 0 0 0 0 ...
> After the patch:
> 1134631 (<filenametruncat>) 0 0 0 0 0 0 0 0 ...
>
> This fixes an issue with hwloc failing to parse /proc/self/stat
> when Ludovic Courtes was testing it in Guix over qemu-aarch64.
>
> Signed-off-by: Philippe_Mathieu-Daudé <phi...@redhat.com>
> Signed-off-by: Brice Goglin <brice.gog...@inria.fr>
>
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -7305,7 +7305,11 @@ static int open_self_stat(void *cpu_env, int fd)
> snprintf(buf, sizeof(buf), "%"PRId64 " ", val);
> } else if (i == 1) {
> /* app name */
> - snprintf(buf, sizeof(buf), "(%s) ", ts->bprm->argv[0]);
> + char *ptr = buf;
> +
> + *ptr++ = '(';
> + ptr = stpncpy(ptr, ts->bprm->argv[0], sizeof(buf) - 3);
> + strcpy(ptr, ") ");
why not just use a format string:
snprintf(buf, sizeof(buf), "(%.125s) ", ts->bprm->argv[0]);
although to be honest when ever I see a bunch of sizeof(buf) code for
strings I tend to re-write it to use the glib GString functions.
> } else if (i == 27) {
> /* stack bottom */
> val = start_stack;
--
Alex Bennée
