[lxc-devel] [lxc/lxc] 4dc964: lxc_setup_tios(): Ignore SIGTTOU and SIGTTIN signa...

[GitHub]

  Branch: refs/heads/master
  Home:   https://github.com/lxc/lxc
  Commit: 4dc96430afec0669228e541935640710dffaa9bd
      https://github.com/lxc/lxc/commit/4dc96430afec0669228e541935640710dffaa9bd
  Author: Thomas Jarosch <thomas.jarosch at intra2net.com>
  Date:   2017-02-08 (Wed, 08 Feb 2017)

  Changed paths:
    M src/lxc/console.c

  Log Message:
  -----------
  lxc_setup_tios(): Ignore SIGTTOU and SIGTTIN signals

Prevent an endless loop while executing lxc-attach in the background:

The kernel might fire SIGTTOU while an ioctl() in tcsetattr()
is executed. When the ioctl() is resumed and retries,
the signal handler interrupts it again.

We can't configure the TTY to stop sending
the signals in the first place since that
is a modification/write to the TTY already.

Still we clear the TOSTOP flag to prevent further signals.

Command to reproduce the hang:
----------------------------
cat > lxc_hang.sh << EOF
/usr/bin/timeout 5s /usr/bin/lxc-attach -n SOMECONTAINER -- /bin/true
EOF
sh lxc_hang.sh    # hangs
----------------------------

Signed-off-by: Thomas Jarosch <thomas.jarosch at intra2net.com>


  Commit: 3a5cb1afffea06ad45a1144bbc3098bb6d5c7e11
      https://github.com/lxc/lxc/commit/3a5cb1afffea06ad45a1144bbc3098bb6d5c7e11
  Author: Stéphane Graber <stgraber at stgraber.org>
  Date:   2017-02-08 (Wed, 08 Feb 2017)

  Changed paths:
    M src/lxc/console.c

  Log Message:
  -----------
  Merge pull request #1424 from brauner/2017-02-08/thomasDOTjaroschATintra2netDOTcom_pty_sigttou

lxc_setup_tios(): Ignore SIGTTOU and SIGTTIN signals


Compare: https://github.com/lxc/lxc/compare/b93fbd248601...3a5cb1afffea