Date: Wed, 14 Oct 1998 08:12:03 -0600 (MDT) From: Darren Whittaker <djw@sage1.sagecorp.com> To: Mike Smith <mike@smith.net.au> Cc: freebsd-current@FreeBSD.ORG, john.young@openmarket.com Subject: Re: problem in 3.0 Message-ID: <Pine.SOL.3.93.981014080742.8720A-100000@sage1.sagecorp.com> In-Reply-To: <199810080530.WAA01135@dingo.cdrom.com>
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Thank you for your email. I have taken your code and modified it to run as
a cgi:
#include <stdio.h>
#include <err.h>
#include <errno.h>
int main(int argc, char *argv[])
{
int i, j;
char buf[256];
FILE *p;
/* output the head */
printf("Content-type: text/html\n");
fflush(stdout);
printf("\n<html><head><title>TESTING</title></head>");
printf("<CENTER><H1>TESTING</CENTER></H1><HR>\n");
printf("<body bgcolor=#ffffff><p><pre>\n");
fflush(stdout);
/* loop using popen */
for (i = 0; i < 10; i++)
{
buf[0] = '\0';
if ((p = popen("/bin/date", "r")) == NULL)
{
printf("popen error: %s\n",strerror(errno));
continue;
}
fgets(buf, sizeof(buf) - 1, p);
printf(buf);
if ((j = pclose(p)) != 0)
printf("pclose error: %s [%d]\n",strerror(j),j);
}
/* output the tail */
fflush(stdout);
printf("</pre><HR><center><small>Copyright © 1998 Open Market, Inc.
All
Rights Reserved.\n");
printf("</small></center></body></html>\n");
fflush(stdout);
}
Here is some of the output when I run it from the web browser:
Wed Oct 14 07:00:13 PDT 1998
pclose error: No child processes [10]
pclose error: No child processes [10]
pclose error: No child processes [10]
pclose error: No child processes [10]
pclose error: No child processes [10]
pclose error: No child processes [10]
pclose error: No child processes [10]
pclose error: No child processes [10]
pclose error: No child processes [10]
What do you think the problem might be?
-Darren
------------------
Darren Whittaker
Senior Software Engineer
Small Enterprise Group
Open Market, Inc.
On Wed, 7 Oct 1998, Mike Smith wrote:
> > We have found a problem with popen. The first popen is executed just fine
> > with a good pclose. The second popen appears to work (though nothing
> > happens) and the pclose returns a 138. This also applies to the system
> > call. The first one works but any after sustem call after the first
> > one fails. We even forked the process but in the child only the first
> > popen work.
>
> I'm not sure that I can follow your problem here. Have you reduced the
> program to its simplest form, eg:
>
> dingo:/tmp>cat p.c
> #include <stdio.h>
> #include <err.h>
>
> void main(void)
> {
> int i, j;
> char buf[256];
> FILE *p;
>
> for (i = 0; i < 10; i++) {
> if ((p = popen("/bin/date", "r")) == NULL)
> err(1, "popen");
> fgets(buf, sizeof(buf) - 1, p);
> printf(buf);
> if ((j = pclose(p)) != 0)
> errx(1, "pclose %d", j);
> }
> }
> dingo:/tmp>gcc -o p p.c
> dingo:/tmp>./p
> Wed Oct 7 22:28:04 PDT 1998
> Wed Oct 7 22:28:04 PDT 1998
> Wed Oct 7 22:28:04 PDT 1998
> Wed Oct 7 22:28:04 PDT 1998
> Wed Oct 7 22:28:04 PDT 1998
> Wed Oct 7 22:28:04 PDT 1998
> Wed Oct 7 22:28:04 PDT 1998
> Wed Oct 7 22:28:04 PDT 1998
> Wed Oct 7 22:28:04 PDT 1998
> Wed Oct 7 22:28:04 PDT 1998
> dingo:/tmp>uname -a
> FreeBSD dingo.cdrom.com 3.0-CURRENT FreeBSD 3.0-CURRENT #2: Wed Sep 16 16:38:28 PDT 1998 mike@dingo.cdrom.com:/local0/src/sys/compile/DINGO i386
>
> What do you mean by "this also applies to the system call"? Which
> system call?
>
> > Now our program is running as a cgi under Apache and works on your 2.x
> > versions just fine.
>
> I'm afraid you're going to have to supply some more detail before we
> can help you further here.
> --
> \\ Sometimes you're ahead, \\ Mike Smith
> \\ sometimes you're behind. \\ mike@smith.net.au
> \\ The race is long, and in the \\ msmith@freebsd.org
> \\ end it's only with yourself. \\ msmith@cdrom.com
>
>
>
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