Attachment 40437 Details for Bug 31790 – git formatted patch

[patch] git formatted patch

0001-Retry-opening-console-device-on-EIO.patch (text/plain), 1.94 KB, created by Martin Pitt on 2010-11-20 09:04:40 UTC

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Creator: Martin Pitt

Created: 2010-11-20 09:04:40 UTC

Size: 1.94 KB

patch

obsolete

>From 3665e8094e50f1f70b02a34d96c005ce152d62a6 Mon Sep 17 00:00:00 2001
>From: Colin Watson <cjwatson@ubuntu.com>
>Date: Sat, 20 Nov 2010 17:57:22 +0100
>Subject: [PATCH] Retry opening console device on EIO
>
>As reported in https://launchpad.net/bugs/544139, ConsoleKit sometimes fails to
>track the active VT. This particular case was tracked down to a race condition
>that happens if you try to open /dev/console while the current TTY is currently
>being closed. This yields an -EIO error, in which case CK should just try
>again.
>
>For a more detailled summary of the problem from a kernel perspective, please
>see https://bugs.launchpad.net/ubuntu/+source/linux/+bug/554172/comments/245 .
>
>https://bugs.freedesktop.org/show_bug.cgi?id=31790
>---
> src/ck-sysdeps-unix.c |   17 +++++++++++++++++
> 1 files changed, 17 insertions(+), 0 deletions(-)
>
>diff --git a/src/ck-sysdeps-unix.c b/src/ck-sysdeps-unix.c
>index e4ab16b..4a1736c 100644
>--- a/src/ck-sysdeps-unix.c
>+++ b/src/ck-sysdeps-unix.c
>@@ -26,6 +26,7 @@
> #include <unistd.h>
> #include <string.h>
> #include <errno.h>
>+#include <time.h>
> #include <sys/types.h>
> #include <sys/stat.h>
> #include <sys/socket.h>
>@@ -150,9 +151,25 @@ open_a_console (char *fnam)
> {
>         int fd;
> 
>+again:
>         fd = open (fnam, O_RDONLY | O_NOCTTY);
>         if (fd < 0 && errno == EACCES)
>                 fd = open (fnam, O_WRONLY | O_NOCTTY);
>+#ifdef __linux__
>+	if (fd < 0 && errno == EIO) {
>+		/* Linux can return EIO if the tty is currently closing,
>+		 * which can happen if multiple processes are opening and
>+		 * closing the console in parallel.  Unfortunately it can
>+		 * also return EIO in more serious situations too (see
>+		 * https://bugs.launchpad.net/bugs/554172), but there isn't
>+		 * much we can do about that since we really need a console
>+		 * fd.
>+		 */
>+		struct timespec ts = { 0, 100000000 }; /* 0.1 seconds */
>+		nanosleep (&ts, NULL);
>+		goto again;
>+	}
>+#endif
> 
>         if (fd < 0)
>                 return -1;
>-- 
>1.7.2.3
>

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