At 05:59 PM 12/26/2003 -0500, Christopher Faylor wrote:
>
>I added strace debugging. You can use that as a clue for what I was
>talking about and make it visible if you can't run exim under strace.
I put a try_to_debug(1). Waiting for something to happen.
>>Also, while running sysinternals I noticed to the exim daemon still had tty
>>related handles, despite setsid(). Ditto for inetd.
>
>Calling setsid does not automatically eliminate tty handles.
>
This is what inetd does:
if (setsid() == -1)
return (-1);
if (!noclose && (fd = open(PATH_DEVNULL, O_RDWR, 0)) != -1) {
(void)dup2(fd, STDIN_FILENO);
(void)dup2(fd, STDOUT_FILENO);
(void)dup2(fd, STDERR_FILENO);
*******
Before your last changes, strace was showing
160 282749 [main] inetd 34569887 close: close (2)
361 283110 [main] inetd 34569887 fhandler_tty_slave::close: decremented open_fhs 0,
archetype usecount 2
198 283308 [main] inetd 34569887 fhandler_tty_slave::close: just exiting because
archetype usecount is > 0
163 283471 [main] inetd 34569887 close: 0 = close (2)
160 283631 [main] inetd 34569887 dtable::dup2: 2 = dup2 (3, 2)
*******
Now usecount is even higher
159 292878 [main] inetd 1086339 close: close (2)
181 293059 [main] inetd 1086339 fhandler_tty_slave::close: decremented open_fhs 0,
archetype usecount 3
313 293372 [main] inetd 1086339 fhandler_tty_slave::close: just returning because
archetype usecount is > 0
175 293547 [main] inetd 1086339 close: 0 = close (2)
158 293705 [main] inetd 1086339 dtable::dup2: 2 = dup2 (3, 2)
I looked at your latest change in syscalls.cc.
It seems to me that setsid should simply call close all the time if (cygheap->ctty)
and let close() take care of usecount.
Ditto in pinfo::set_ctty where a problem similar to the one you addressed also exists.
I don't think that will take care of everything, but I can't follow what's happening
when tracing sh -c inetd
Usecount jumps by 2 when open_fhs goes up by 1.
179 854139 [main] SH 34649867 fhandler_tty_slave::open: /dev/tty1 opened,
incremented open_fhs 3, archetype usecount 4
237 880231 [main] sh 34649867 fhandler_tty_slave::dup: incremented open_fhs 4,
archetype usecount 6
The trace is on http://mysite.verizon.net/phumblet/trace if interested.
Pierre
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