diff options
| author | Phil Sutter <phil@nwl.cc> | 2023-12-19 00:56:07 +0100 |
|---|---|---|
| committer | Phil Sutter <phil@nwl.cc> | 2023-12-21 14:33:47 +0100 |
| commit | 63ab5b8906f6913a14d38ec231f21daa760339a9 (patch) | |
| tree | c11fb0a551885592aefc7160b23328860285d9ab /iptables/xshared.c | |
| parent | f5cf76626d95d2c491a80288bccc160c53b44e88 (diff) | |
iptables-legacy: Fix for mandatory lock waiting
Parameter 'wait' passed to xtables_lock() signals three modes of
operation, depending on its value:
0: --wait not specified, do not wait if lock is busy
-1: --wait specified without value, wait indefinitely until lock becomes
free
>0: Wait for 'wait' seconds for lock to become free, abort otherwise
Since fixed commit, the first two cases were treated the same apart from
calling alarm(0), but that is a nop if no alarm is pending. Fix the code
by requesting a non-blocking flock() in the second case. While at it,
restrict the alarm setup to the third case only.
Cc: Jethro Beekman <jethro@fortanix.com>
Cc: howardjohn@google.com
Cc: Antonio Ojea <antonio.ojea.garcia@gmail.com>
Closes: https://bugzilla.netfilter.org/show_bug.cgi?id=1728
Fixes: 07e2107ef0cbc ("xshared: Implement xtables lock timeout using signals")
Signed-off-by: Phil Sutter <phil@nwl.cc>
Diffstat (limited to 'iptables/xshared.c')
| -rw-r--r-- | iptables/xshared.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/iptables/xshared.c b/iptables/xshared.c index 5cae62b4..43fa929d 100644 --- a/iptables/xshared.c +++ b/iptables/xshared.c @@ -270,7 +270,7 @@ static int xtables_lock(int wait) return XT_LOCK_FAILED; } - if (wait != -1) { + if (wait > 0) { sigact_alarm.sa_handler = alarm_ignore; sigact_alarm.sa_flags = SA_RESETHAND; sigemptyset(&sigact_alarm.sa_mask); @@ -278,7 +278,7 @@ static int xtables_lock(int wait) alarm(wait); } - if (flock(fd, LOCK_EX) == 0) + if (flock(fd, LOCK_EX | (wait ? 0 : LOCK_NB)) == 0) return fd; if (errno == EINTR) { |