| Message ID | 20180604123043.13985-1-berrange@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | chardev: don't splatter terminal settings on exit if not previously set | expand |
On Mon, Jun 4, 2018 at 2:30 PM, Daniel P. Berrangé <berrange@redhat.com> wrote: > The stdio chardev finalize method calls term_exit() to restore the > original terminal settings that were saved in the "oldtty" global. If > the qemu_chr_open_stdio() method exited with an error, we might not have > any original terminal settings saved in "oldtty" yet. > > eg > > $ qemu-system-x86_64 -monitor stdio -daemonize > qemu-system-x86_64: -monitor stdio: cannot use stdio with -daemonize > > will cause QEMU to splatter the terminal settings with an all-zeros > "struct termios", with predictably unpleasant results. Fortunately the > existing "stdio_in_use" flag is suitable witness for whether "oldtty" > contains settings that need restoring. > > Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> > --- > chardev/char-stdio.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/chardev/char-stdio.c b/chardev/char-stdio.c > index d83e60e787..8039e85f64 100644 > --- a/chardev/char-stdio.c > +++ b/chardev/char-stdio.c > @@ -46,8 +46,10 @@ static bool stdio_echo_state; > > static void term_exit(void) > { > - tcsetattr(0, TCSANOW, &oldtty); > - fcntl(0, F_SETFL, old_fd0_flags); > + if (stdio_in_use) { > + tcsetattr(0, TCSANOW, &oldtty); > + fcntl(0, F_SETFL, old_fd0_flags); > + } > } > > static void qemu_chr_set_echo_stdio(Chardev *chr, bool echo) > -- > 2.17.0 >
diff --git a/chardev/char-stdio.c b/chardev/char-stdio.c index d83e60e787..8039e85f64 100644 --- a/chardev/char-stdio.c +++ b/chardev/char-stdio.c @@ -46,8 +46,10 @@ static bool stdio_echo_state; static void term_exit(void) { - tcsetattr(0, TCSANOW, &oldtty); - fcntl(0, F_SETFL, old_fd0_flags); + if (stdio_in_use) { + tcsetattr(0, TCSANOW, &oldtty); + fcntl(0, F_SETFL, old_fd0_flags); + } } static void qemu_chr_set_echo_stdio(Chardev *chr, bool echo)
The stdio chardev finalize method calls term_exit() to restore the original terminal settings that were saved in the "oldtty" global. If the qemu_chr_open_stdio() method exited with an error, we might not have any original terminal settings saved in "oldtty" yet. eg $ qemu-system-x86_64 -monitor stdio -daemonize qemu-system-x86_64: -monitor stdio: cannot use stdio with -daemonize will cause QEMU to splatter the terminal settings with an all-zeros "struct termios", with predictably unpleasant results. Fortunately the existing "stdio_in_use" flag is suitable witness for whether "oldtty" contains settings that need restoring. Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> --- chardev/char-stdio.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)