From: Rich Felker <dalias@libc.org>
To: musl@lists.openwall.com
Subject: Re: Add login_tty
Date: Sat, 20 Dec 2014 19:58:21 -0500 [thread overview]
Message-ID: <20141221005821.GG4574@brightrain.aerifal.cx> (raw)
In-Reply-To: <20141103182954.GA4423@euler>
On Mon, Nov 03, 2014 at 07:29:54PM +0100, Felix Janda wrote:
> Thanks for the review. Below a new version.
Sorry I didn't get around to reviewing this right away.
> #include <pty.h>
> #include <utmp.h>
> #include <unistd.h>
>
> int forkpty(int *m, char *name, const struct termios *tio, const struct winsize *ws)
> {
> int s, ec, p[2];
> pid_t pid;
>
> if (openpty(m, &s, name, tio, ws) < 0) return -1;
> if (pipe2(p, O_CLOEXEC)) {
> close(s);
> goto fail;
> }
>
> pid = fork();
> if (!pid) {
> close(*m);
> close(p[0]);
> ec = login_tty(s);
login_tty could end up closing the pipe if stdin/out/err were
initially closed in the parent, since p[1] might be 0/1/2 in that
case. I think we need to check for this and move p[1] to a new fd in
that case (and fail if that fails) before calling login_tty.
> while (write(p[1], &ec, sizeof ec) < 0);
> if (ec) _exit(127);
> close(p[1]);
> return 0;
> }
> close(s);
> close(p[1]);
> if (pid > 0) read(p[0], &ec, sizeof ec);
This read probably needs to retry-loop, in case the parent has
interrupting signal handlers.
> close(p[0]);
> if (pid > 0) {
> if (!ec) return pid;
> waitpid(pid, &(int){0}, 0);
I think waitpid could in principle fail too, but it probably shouldn't
since the process is already dead at the time waitpid is called.
> }
> fail:
> close(*m);
> return -1;
> }
Otherwise it looks okay now.
Rich
next prev parent reply other threads:[~2014-12-21 0:58 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-25 18:57 Felix Janda
2014-08-25 22:43 ` Rich Felker
2014-08-26 16:56 ` Felix Janda
2014-08-29 18:44 ` Felix Janda
2014-09-04 21:22 ` Szabolcs Nagy
2014-09-04 21:33 ` Rich Felker
2014-09-04 22:31 ` Justin Cormack
2014-09-05 17:23 ` Felix Janda
2014-09-05 17:29 ` Rich Felker
2014-09-05 18:52 ` Felix Janda
2014-10-31 16:19 ` Rich Felker
2014-11-01 21:15 ` Felix Janda
2014-11-01 21:45 ` Rich Felker
2014-11-01 22:07 ` Szabolcs Nagy
2014-11-01 22:27 ` Felix Janda
2014-11-01 22:43 ` Rich Felker
2014-11-01 22:56 ` Felix Janda
2014-11-02 0:09 ` Rich Felker
2014-11-02 14:19 ` Felix Janda
2014-11-02 16:28 ` Rich Felker
2014-11-02 18:56 ` Felix Janda
2014-11-02 22:28 ` Rich Felker
2014-11-03 18:29 ` Felix Janda
2014-12-21 0:58 ` Rich Felker [this message]
2014-12-21 1:15 ` Rich Felker
2014-12-21 1:38 ` Rich Felker
2014-12-21 2:59 ` Rich Felker
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