[ovs-dev] [PATCH] fatal-signal: Remove snprintf.

William Tu u9012063 at gmail.com
Wed Mar 25 15:52:37 UTC 2020


On Wed, Mar 25, 2020 at 8:39 AM Ben Pfaff <blp at ovn.org> wrote:
>
> On Wed, Mar 25, 2020 at 07:34:13AM -0700, William Tu wrote:
> > Function snprintf is not async-signal-safe.  Replace it with
> > our own implementation.  Example ovs-vswitchd.log output:
> >   2020-03-25T01:08:19.673Z|00050|memory|INFO|handlers:2 ports:3
> >   SIGSEGV detected, backtrace:
> >   0x4872d9         <fatal_signal_handler+0x49>
> >   0x7f4e2ab974b0   <killpg+0x40>
> >   0x7f4e2ac5d74d   <__poll+0x2d>
> >   0x531098         <time_poll+0x108>
> >   0x51aefc         <poll_block+0x8c>
> >   0x445ca9         <udpif_revalidator+0x289>
> >   0x5056fd         <ovsthread_wrapper+0x7d>
> >   0x7f4e2b65f6ba   <start_thread+0xca>
> >   0x7f4e2ac6941d   <clone+0x6d>
> >   0x0              <+0x0>
> >
> > Tested-at: https://travis-ci.org/github/williamtu/ovs-travis/builds/666596271
> > Signed-off-by: William Tu <u9012063 at gmail.com>
>
> I didn't test this, but I assume you did.
>
> The traditional way to get a hex digit is to write "0123456789abcdef"[x],
> although your way is fine too.

Thanks! I think this looks better.
>
> If the function name is long, this will overflow the line buffer.

OK, I will use strncat

>
> There's no reason to write "line =" in each of these, since strcat()
> just returns its first argument.
>
OK, will fix it.
Thanks for your feedback.
William


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