Re: [bug-gawk] Does gawk deal with signal pipe correctly?

[Peng Yu]

Hi Aharon, I am not familiar with the C API about PIPEs. Could you
please help explain what the bug was and how it is fixed? Why were you
not able to reproduce the bug? Is there anything special in a VM
environment?

On Sun, Jun 17, 2018 at 1:46 PM,  <address@hidden> wrote:
> OK. I banged on this some more and managed to track it down.
> A fix is below.  I will push this out to git shortly.
>
> Thanks,
>
> Arnold
>
> Peng Yu <address@hidden> wrote:
>
>> $ awk --version | head -n 1
>> GNU Awk 4.2.0, API: 2.0 (GNU MPFR 4.0.1, GNU MP 6.1.2)
>>
>> On Sun, Jun 17, 2018 at 6:34 AM,  <address@hidden> wrote:
>> > What is the output from gawk --version?
>> >
>> > Peng Yu <address@hidden> wrote:
>> >
>> >> Here is what I have. It is tested on a virtual machine (hosted on KVM
>> >> on another Ubuntu physical machine). Are you able to get the same
>> >> version vm to test?
>> >>
>> >> $ cat DCt7x2zD | awk '{ print }' | head -n 1
>> >>
>> >> $ echo address@hidden
>> >> 0 141 0
>> >> $ cat DCt7x2zD | awk '{ print }' | head -n 1
>> >>
>> >> $ echo address@hidden
>> >> 0 1 0
> --------------------------
> diff --git a/awk.h b/awk.h
> index f32e30a..31e661d 100644
> --- a/awk.h
> +++ b/awk.h
> @@ -1574,7 +1574,7 @@ extern struct redirect *redirect_string(const char 
> *redir_exp_str,
>                 int *errflg, int extfd, bool failure_fatal);
>  extern NODE *do_close(int nargs);
>  extern int flush_io(void);
> -extern int close_io(bool *stdio_problem);
> +extern int close_io(bool *stdio_problem, bool *got_EPIPE);
>  typedef enum { CLOSE_ALL, CLOSE_TO, CLOSE_FROM } two_way_close_type;
>  extern int close_rp(struct redirect *rp, two_way_close_type how);
>  extern int devopen_simple(const char *name, const char *mode, bool 
> try_real_open);
> diff --git a/debug.c b/debug.c
> index ed763e3..2e68cde 100644
> --- a/debug.c
> +++ b/debug.c
> @@ -5405,11 +5405,11 @@ save_options(const char *file)
>  static void
>  close_all()
>  {
> -       bool stdio_problem;
> +       bool stdio_problem, got_EPIPE;
>         struct command_source *cs;
>
>         (void) nextfile(& curfile, true);       /* close input data file */
> -       (void) close_io(& stdio_problem);
> +       (void) close_io(& stdio_problem, & got_EPIPE);
>         if (cur_srcfile->fd != INVALID_HANDLE) {
>                 close(cur_srcfile->fd);
>                 cur_srcfile->fd = INVALID_HANDLE;
> diff --git a/interpret.h b/interpret.h
> index 20fcb7a..8408a53 100644
> --- a/interpret.h
> +++ b/interpret.h
> @@ -110,6 +110,7 @@ top:
>                 case Op_atexit:
>                 {
>                         bool stdio_problem = false;
> +                       bool got_EPIPE = false;
>
>                         /* avoid false source indications */
>                         source = NULL;
> @@ -125,7 +126,7 @@ top:
>                          * and pipes, in that it doesn't affect their exit 
> status.
>                          * So we no longer do either.
>                          */
> -                       (void) close_io(& stdio_problem);
> +                       (void) close_io(& stdio_problem, & got_EPIPE);
>                         /*
>                          * However, we do want to exit non-zero if there was 
> a problem
>                          * with stdout/stderr, so we reinstate a slightly 
> different
> @@ -135,6 +136,9 @@ top:
>                                 exit_val = 1;
>
>                         close_extensions();
> +
> +                       if (got_EPIPE)
> +                               die_via_sigpipe();
>                 }
>                         break;
>
> diff --git a/io.c b/io.c
> index 9ca29da..a3d68ce 100644
> --- a/io.c
> +++ b/io.c
> @@ -1474,12 +1474,13 @@ flush_io()
>  /* close_io --- close all open files, called when exiting */
>
>  int
> -close_io(bool *stdio_problem)
> +close_io(bool *stdio_problem, bool *got_EPIPE)
>  {
>         struct redirect *rp;
>         struct redirect *next;
>         int status = 0;
>
> +       *stdio_problem = *got_EPIPE = false;
>         errno = 0;
>         for (rp = red_head; rp != NULL; rp = next) {
>                 next = rp->next;
> @@ -1505,6 +1506,9 @@ close_io(bool *stdio_problem)
>  #endif
>                 if (errno != EPIPE)
>                         warning(_("error writing standard output (%s)"), 
> strerror(errno));
> +               else
> +                       *got_EPIPE = true;
> +
>                 status++;
>                 *stdio_problem = true;
>         }
> @@ -1515,6 +1519,9 @@ close_io(bool *stdio_problem)
>  #endif
>                 if (errno != EPIPE)
>                         warning(_("error writing standard error (%s)"), 
> strerror(errno));
> +               else
> +                       *got_EPIPE = true;
> +
>                 status++;
>                 *stdio_problem = true;
>         }



-- 
Regards,
Peng