Re: Bug#271758: ud segfault (was: When will the amd64 port be stable?)
On Sun, Dec 12, 2004 at 05:18:37AM +0000, Steve McIntyre wrote:
> David Liontooth <liontooth@cogweb.net> wrote:
> >Goswin von Brederlow wrote:
> >>
> >>And now the same with -f please. I didn't see a segfault in the starce
> >>and it is probably its child that dies.
> >>
> >>You can also compile the ud with debug infos and run it in gdb.
> >>
> >>MfG
> >> Goswin
> >>
> >>
> >Hi Goswin,
> >
> >So this is not behavior others are seeing?
> >I have the pleasure of sending you a thousand EBADF reports below --
> >you're likely only interested in the last few lines:
>
> OK, so I'm bored. I've just looked at the bug and found the
> problem. ud's source is quite ugly, suggesting a novice author. I can
> recreate the bug quite readily here, and it's crashing down below a
> sprintf() call:
>
> (gdb) bt
> #0 0x0000002a956e9980 in strlen () from /lib/libc.so.6
> #1 0x0000002a956b7c75 in vfprintf () from /lib/libc.so.6
> #2 0x0000002a956d6ec5 in vsprintf () from /lib/libc.so.6
> #3 0x0000002a956be50a in sprintf () from /lib/libc.so.6
> #4 0x0000000000401340 in get_kernel_version (kernel_version=0x7fbffff544 "running Linux 2.6.9", IsCurrent=0) at ud.c:150
> #5 0x00000000004020c5 in main (argc=1, argv=0x7fbffff540) at ud.c:822
>
> The reason for this becomes clear once you turn on warnings in the
> compilation:
>
> gcc -DPACKAGE=\"ud\" -DVERSION=\"0.7.1\" -DSTDC_HEADERS=1 -DHAVE_UNISTD_H=1 -DRETSIGTYPE=void -DHAVE_GETHOSTNAME=1 -I. -I. -g -O2 -Wall -W -c ud.c
> ud.c: In function `get_kernel_version':
> ud.c:150: warning: implicit declaration of function `ctime'
> ud.c:150: warning: format argument is not a pointer (arg 3)
>
> ctime is returning a pointer rather than an int. Simply adding
> "#include <time.h>" to the top of the ud.c source file fixes this
> bug. Prototypes are there for a reason!
>
> Turning on warnings also highlights other silly coding bugs, but I'll
> leave those for other people.
Cheers for that, I will prepare an upload to close all the warnings.
Steve
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