diff options
| author | Jeff Dike <jdike@addtoit.com> | 2007-12-01 12:16:30 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-12-03 08:13:17 -0800 |
| commit | ce3b642d42f36406112ab474c03d81c5941d9398 (patch) | |
| tree | 76a3c469248217a1d2e1648f749ad93864fe2856 /arch/um/drivers | |
| parent | 0a765329ed656ef08915c8be4aba9031ba467ee4 (diff) | |
uml: work around host tcsetattr bug
Under the conditions that UML uses it, tcgetattr is guaranteed to return
-EINTR when the console is attached to /dev/ptmx, making generic_console_write
hang because it loops, calling tcgetattr until it succeeds. This is a host
bug - see http://marc.info/?l=linux-kernel&m=119618990807182&w=2 for the
details.
This patch works around it by blocking SIGIO while the terminal attributes are
being fiddled.
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/um/drivers')
| -rw-r--r-- | arch/um/drivers/chan_user.c | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/arch/um/drivers/chan_user.c b/arch/um/drivers/chan_user.c index b88e93b3a39..025764089ac 100644 --- a/arch/um/drivers/chan_user.c +++ b/arch/um/drivers/chan_user.c @@ -74,10 +74,16 @@ void generic_free(void *data) int generic_console_write(int fd, const char *buf, int n) { + sigset_t old, no_sigio; struct termios save, new; int err; if (isatty(fd)) { + sigemptyset(&no_sigio); + sigaddset(&no_sigio, SIGIO); + if (sigprocmask(SIG_BLOCK, &no_sigio, &old)) + goto error; + CATCH_EINTR(err = tcgetattr(fd, &save)); if (err) goto error; @@ -97,8 +103,11 @@ int generic_console_write(int fd, const char *buf, int n) * Restore raw mode, in any case; we *must* ignore any error apart * EINTR, except for debug. */ - if (isatty(fd)) + if (isatty(fd)) { CATCH_EINTR(tcsetattr(fd, TCSAFLUSH, &save)); + sigprocmask(SIG_SETMASK, &old, NULL); + } + return err; error: return -errno; |