Re: [Chicken-users] pressed Ctrl-\ and got segmentation fault

[Jim Ursetto]

Ah, so the segfault also occurs with plain old `cat` then?  I think we can 
close this bug ;) Thanks for tracking this down further.

On Jun 23, 2013, at 7:14, Moritz Wilhelmy <address@hidden> wrote:

> On 21.06.2013 22:34, John Cowan wrote:
>> I can confirm that on 32-bit Linux.  On Cygwin, however, typing ^\ does
>> trigger a SIGSEGV with dumped core (except that it doesn't actually dump
>> core because the Windows kernel can't do that).  Both systems are running
>> version 4.8.2 (rev ea02c9a), and there is no .csirc file.  Readline is
>> not involved: the config line says "manyargs dload ptables" only.
> 
> Right.
> 
> $ cat
> ^\
> Segmentation fault (core dumped)
> 
> But:
> $ cat test.c
> #include <stdio.h>
> #include <signal.h>
> #include <unistd.h>
> 
> void sighandler(int sig)
> {
>    printf("Caught signal: %d\n", sig);
> }
> 
> main()
> {
>    struct sigaction s;
>    memset(&s, 0, sizeof(s));
>    s.sa_handler = sighandler;
>    
>    sigaction(SIGSEGV, &s, 0);
>    sigaction(SIGQUIT, &s, 0);
> 
>    while (1)
>        sleep(1);
> 
>    return 0;
> }
> $ ./test &
> [2] 3720
> $ kill -QUIT %2
> Caught signal: 3
> $ kill -SEGV %2
> Caught signal: 11
> $ ./test
> ^\
> Caught signal: 3
> 
> If you comment out sigaction(SIGQUIT, &s, 0); it prints
> Segmentation fault (core dumped)
> although it is actually killed by SIGQUIT, not SIGSEGV.
> 
> This leads me to believe that something inside Cygwin just prints the
> wrong string for some reason, like for instance Windows or Cygwin
> returning a bogus value for WTERMSIG in the wait-syscall the shell
> makes, and that this is not a Chicken bug.
> 
> However, this puzzles me:
> $ find >/dev/null
> ^\
> Quit (core dumped)
> $ cat >/dev/null
> ^\
> Segmentation fault (core dumped)
> $ cat /dev/zero >/dev/null
> ^\
> Quit (core dumped)
> 
> So it might be that processes which are killed while doing I/O print
> "Quit" and "Segmentation fault" otherwise.
> 
> 
> Best regards,
> 
> Moritz
> 
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