iptables: flush stdout after every verbose log.

Ensures that each logged line is flushed to stdout after it's
written, and not held in any buffer.

Places to modify found via:
  git grep -C5 'fputs[(]buffer, stdout[)];'

On Android iptables-restore -v is run as netd daemon's child process
and fed actions via pipe.  '#PING' is used to verify the child
is still responsive, and thus needs to be unbuffered.

Luckily if you're running iptables-restore in verbose mode you
probably either don't care about performance or - like Android
- actually need this.

Test: builds, required on Android for ip6?tables-restore netd
  subprocess health monitoring.
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 3 insertions, 1 deletions

diff --git a/iptables/iptables-restore.c b/iptables/iptables-restore.c
index b0a51d49..fea04842 100644
--- a/iptables/iptables-restore.c
+++ b/iptables/iptables-restore.c
@@ -178,8 +178,10 @@ ip46tables_restore_main(const struct iptables_restore_cb *cb,
 		if (buffer[0] == '\n')
 			continue;
 		else if (buffer[0] == '#') {
-			if (verbose)
+			if (verbose) {
 				fputs(buffer, stdout);
+				fflush(stdout);
+			}
 			continue;
 		} else if ((strcmp(buffer, "COMMIT\n") == 0) && (in_table)) {
 			if (!testing) {