Thanks for finding this. I'll incorporate the fix.
Amit
On Oct 26, 8:41 pm, Francis Devereux <[EMAIL PROTECTED]> wrote:
> Hi,
>
> I was playing around with procfs today, and when I did "cat /proc/*/
> cmdline" procfs crashed with a segmentation fault. I re-ran procfs in
> gdb and saw that the crash was caused by the while loop in
> getproccmdline trying to read past the end of target_argv. This was
> when it was getting the command-line for a postgresql process that had
> changed its argc, so the command-line reported by ps was "postgres:
> writer process
> ".
>
> I added a check for the end of the target_argv buffer and re-rand
> "cat /proc/*/cmdline", which now works without a crash. The patch is
> below.
>
> Regards,
>
> Francis
>
> P.S. this is with procfs from subversion r1273, and MacFuse 1.9.23.
>
> Index: procfs.cc
> ===================================================================
> --- procfs.cc (revision 1273)
> +++ procfs.cc (working copy)
> @@ -1816,7 +1816,7 @@
> {
> int i, mib[4], rlen, tlen, thislen;
> int argmax, target_argc;
> - char *target_argv;
> + char *target_argv, *target_argv_end;
> char *cp;
> size_t size;
>
> @@ -1837,6 +1837,8 @@
> return -1;
> }
>
> + target_argv_end = target_argv + argmax;
> +
> mib[0] = CTL_KERN;
> mib[1] = KERN_PROCARGS2;
> mib[2] = pid;
> @@ -1853,8 +1855,14 @@
> rlen = len;
> tlen = 0;
> for (i = 1; i < target_argc + 1; i++) {
> - while (*cp == '\0')
> + while (cp < target_argv_end && *cp == '\0')
> cp++;
> + if (cp == target_argv_end) {
> + // We have reached the end of target_argv without finding
> + // target_argc arguments. This can happen when a process
> has
> + // changed its argv (for example, postgresql does this).
> + break;
> + }
> thislen = snprintf(cmdlinebuf + tlen, rlen, "%s ", cp);
> tlen += thislen;
> rlen -= thislen;
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