Re: gawk's inet hanging?

[Jeff Chua]

On Fri, Nov 6, 2009 at 6:17 PM, Aharon Robbins <address@hidden> wrote:

> Hi. I'll review the patch. I note that gawk is checking an environment
> variable and not an awk variable, thus your initial script was not
> correct.


Aharon,

Have you had a chance to look into the patch I sent earlier (see below)?
Without it, gawk would hang forever instead of returning an error.

Thanks,
Jeff




On Fri, Nov 6, 2009 at 11:27 AM, Jeff Chua <address@hidden>wrote:

>
>
> Arnold,
>
>
>  I'm trying put gawk inet connection to the local smtp port and would like
>> it to detect error conditions, but don't know how.
>>
>
>
> I looked into the source code and it seems the code is testing "unsigned
> long" for negative value ... and that won't work.
>
> I've also modify the code to return ERRNO to user instead of exiting with a
> fatal error in case the socket is no available, and also modified sleep() to
> usleep() and allow GAWK_MSEC_SLEEP to retry in milliseconds interval instead
> of the default 1 second.
>
> Tested with this script.
>
>
> export GAWK_SOCK_RETRIES=3;
> export GAWK_MSEC_SLEEP=200;
> gawk 'BEGIN {
>
>        serv = "/inet/tcp/0/localhost/25";
>        status = (serv |& getline);
>        printf("(%s) (%s) [%s]\n", ERRNO, status, $0);
> }'
>
>
> Patch below. Please consider.
>
>
> Thanks,
> Jeff.
>
>
> --- gawk-stable/io.c    2009-10-30 21:46:43.000000000 +0800
> +++ a/io.c      2009-11-06 10:55:01.000000000 +0800
> @@ -708,10 +708,12 @@
>                        if (! two_way_open(str, rp)) {
>  #ifdef HAVE_SOCKETS
>                                /* multiple messages make life easier for
> translators */
> -                               if (STREQN(str, "/inet/", 6))
> -                                       fatal(_("can't open two way socket
> `%s' for input/output (%s)"),
> -                                               str, strerror(errno));
> -                               else
> +                               if (STREQN(str, "/inet/", 6)) {
> +                                       *errflg = errno;
> +                                       free_temp(tmp);
> +                                       free_rp(rp);
> +                                       return NULL;
> +                               } else
>  #endif
>                                        fatal(_("can't open two way pipe
> `%s' for input/output (%s)"),
>                                                str, strerror(errno));
> @@ -1457,27 +1459,41 @@
>
>                {
>  #define DEFAULT_RETRIES 20
> -                       static unsigned long def_retries = DEFAULT_RETRIES;
> +                       static long def_retries = DEFAULT_RETRIES;
>                        static int first_time = TRUE;
> -                       unsigned long retries = 0;
> +                       long retries = 0;
> +                       static long msleep = 1000;
>
>                        if (first_time) {
>                                char *cp, *end;
> -                               unsigned long count = 0;
> +                               long count = 0;
> +                               char *ms2;
>
>                                first_time = FALSE;
> -                               if ((cp = getenv("GAWK_SOCK_RETRIES")) !=
> NULL) {
> +
> +                               if((cp = getenv("GAWK_SOCK_RETRIES")) !=
> NULL) {
>                                        count = strtoul(cp, &end, 10);
>                                        if (end != cp && count > 0)
>                                                def_retries = count;
> +                                       //warning(_("retries %d %d"),
> def_retries, count);
> +                               }
> +
> +                               if((ms2 = getenv("GAWK_MSEC_SLEEP")) !=
> NULL) {
> +                                       msleep = atoi(ms2);
> +                                       if(msleep < 0)
> +                                               msleep = 1000;
> +                                       //warning(_("msleep %d"), msleep);
>                                }
>                        }
>                        retries = def_retries;
>
> +                       msleep *= 1000;
> +
>                        do {
>                                openfd = socketopen(protocol, localpname,
> cp, hostname);
> +                               //warning(_("retries %d"), retries);
>                                retries--;
> -                       } while (openfd == INVALID_HANDLE && retries >= 0
> && sleep(1) == 0);
> +                       } while (openfd == INVALID_HANDLE && retries >= 0
> && usleep(msleep) == 0);
>                }
>
>                *localpnamelastcharp = '/';
>
>
>