* PATCH: bug fix: infinite loop when tty disappears
@ 2019-09-27 12:05 Roman Perepelitsa
0 siblings, 0 replies; only message in thread
From: Roman Perepelitsa @ 2019-09-27 12:05 UTC (permalink / raw)
To: Zsh hackers list
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When TTY disappears and there is at least one fd watcher,
raw_getbyte() can enter an infinite loop where it keeps calling poll()
over and over again.
To reproduce, open a terminal, start zsh and type this:
rm -f /tmp/fifo
mkfifo /tmp/fifo
exec 3<>/tmp/fifo
do-nothing() {}
zle -F 3 do-nothing
Then make TTY disappear. For example, kill the parent with `kill -9
$PPID` and close the terminal window if it's still there. Observe that
zsh is consuming 100% CPU. Note that do-nothing() never gets called.
This patch makes the poll() loop in raw_getbyte() terminate when TTY
is signalling POLLHUP. This makes the behavior consistent with the
case where TTY disappears while no fd watchers are installed.
Roman.
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diff --git a/Src/Zle/zle_main.c b/Src/Zle/zle_main.c
index d3b9aeab8..22c12cf1f 100644
--- a/Src/Zle/zle_main.c
+++ b/Src/Zle/zle_main.c
@@ -708,7 +708,7 @@ raw_getbyte(long do_keytmout, char *cptr, int full)
*/
if (
# ifdef HAVE_POLL
- (fds[0].revents & POLLIN)
+ (fds[0].revents & (POLLIN|POLLERR|POLLHUP|POLLNVAL))
# else
FD_ISSET(SHTTY, &foofd)
# endif
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2019-09-27 12:05 PATCH: bug fix: infinite loop when tty disappears Roman Perepelitsa
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