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commit 24f8174646123c2833bc87967b366796231b04e0
Author: Liping Zhang <zlpnobody@gmail.com>
Date: Sun Feb 5 21:57:34 2017 +0800
xshared: do not lock again and again if "-w" option is not specified
After running the following commands, some confusing messages was printed
out:
# while : ; do
iptables -A INPUT &
iptables -D INPUT &
done
[...]
Another app is currently holding the xtables lock; still -9s 0us time
ahead to have a chance to grab the lock...
Another app is currently holding the xtables lock; still -29s 0us time
ahead to have a chance to grab the lock...
If "-w" option is not specified, the "wait" will be zero, so we should
check whether the timer_left is less than wait_interval before we call
select to sleep.
Also remove unused "BASE_MICROSECONDS" and "struct timeval waited_time"
introduced by commit e8f857a5a151 ("xtables: Add an interval option for
xtables lock wait").
Fixes: e8f857a5a151 ("xtables: Add an interval option for xtables lock wait")
Signed-off-by: Liping Zhang <zlpnobody@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
diff --git a/iptables/xshared.c b/iptables/xshared.c
index cccb8ae..055acf2 100644
--- a/iptables/xshared.c
+++ b/iptables/xshared.c
@@ -17,7 +17,6 @@
#include "xshared.h"
#define XT_LOCK_NAME "/run/xtables.lock"
-#define BASE_MICROSECONDS 100000
/*
* Print out any special helps. A user might like to be able to add a --help
@@ -249,13 +248,11 @@ void xs_init_match(struct xtables_match *match)
bool xtables_lock(int wait, struct timeval *wait_interval)
{
- struct timeval time_left, wait_time, waited_time;
+ struct timeval time_left, wait_time;
int fd, i = 0;
time_left.tv_sec = wait;
time_left.tv_usec = 0;
- waited_time.tv_sec = 0;
- waited_time.tv_usec = 0;
fd = open(XT_LOCK_NAME, O_CREAT, 0600);
if (fd < 0)
@@ -264,6 +261,9 @@ bool xtables_lock(int wait, struct timeval *wait_interval)
while (1) {
if (flock(fd, LOCK_EX | LOCK_NB) == 0)
return true;
+ else if (wait >= 0 && timercmp(&time_left, wait_interval, <))
+ return false;
+
if (++i % 10 == 0) {
if (wait != -1)
fprintf(stderr, "Another app is currently holding the xtables lock; "
@@ -279,10 +279,7 @@ bool xtables_lock(int wait, struct timeval *wait_interval)
if (wait == -1)
continue;
- timeradd(&waited_time, wait_interval, &waited_time);
timersub(&time_left, wait_interval, &time_left);
- if (!timerisset(&time_left))
- return false;
}
}