From 1d12f7bb86fba1d65938ed2c85b7a0f11424281b Mon Sep 17 00:00:00 2001
From: Yusuke Sato <yusukes@google.com>
Date: Thu, 20 Aug 2015 22:44:31 -0700
Subject: Add '-w' option to ip[6]tables-restore

so ip[6]tables-restrore and ip[6]tables commands can be safely
executed in parallel.

Bug: 21725996
Change-Id: I4d0c0e5ff9e7881d9ebdfa5d4c733029703bb8de
---
 iptables/ip6tables-restore.c | 18 +++++++++++++++---
 iptables/iptables-restore.c  | 18 +++++++++++++++---
 2 files changed, 30 insertions(+), 6 deletions(-)

diff --git a/iptables/ip6tables-restore.c b/iptables/ip6tables-restore.c
index b8b9e0dd..31bc502f 100644
--- a/iptables/ip6tables-restore.c
+++ b/iptables/ip6tables-restore.c
@@ -15,6 +15,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include "ip6tables.h"
+#include "xshared.h"
 #include "xtables.h"
 #include "libiptc/libip6tc.h"
 #include "ip6tables-multi.h"
@@ -25,7 +26,7 @@
 #define DEBUGP(x, args...)
 #endif
 
-static int binary = 0, counters = 0, verbose = 0, noflush = 0;
+static int binary = 0, counters = 0, verbose = 0, noflush = 0, wait = 0;
 
 /* Keeping track of external matches and targets.  */
 static const struct option options[] = {
@@ -35,6 +36,7 @@ static const struct option options[] = {
 	{.name = "test",     .has_arg = false, .val = 't'},
 	{.name = "help",     .has_arg = false, .val = 'h'},
 	{.name = "noflush",  .has_arg = false, .val = 'n'},
+	{.name = "wait",     .has_arg = false, .val = 'w'},
 	{.name = "modprobe", .has_arg = true,  .val = 'M'},
 	{.name = "table",    .has_arg = true,  .val = 'T'},
 	{NULL},
@@ -44,13 +46,14 @@ static void print_usage(const char *name, const char *version) __attribute__((no
 
 static void print_usage(const char *name, const char *version)
 {
-	fprintf(stderr, "Usage: %s [-b] [-c] [-v] [-t] [-h]\n"
+	fprintf(stderr, "Usage: %s [-b] [-c] [-v] [-t] [-h] [-w]\n"
 			"	   [ --binary ]\n"
 			"	   [ --counters ]\n"
 			"	   [ --verbose ]\n"
 			"	   [ --test ]\n"
 			"	   [ --help ]\n"
 			"	   [ --noflush ]\n"
+			"	   [ --wait ]\n"
 			"          [ --modprobe=<command>]\n", name);
 
 	exit(1);
@@ -204,7 +207,7 @@ int ip6tables_restore_main(int argc, char *argv[])
 	init_extensions6();
 #endif
 
-	while ((c = getopt_long(argc, argv, "bcvthnM:T:", options, NULL)) != -1) {
+	while ((c = getopt_long(argc, argv, "bcvthnwM:T:", options, NULL)) != -1) {
 		switch (c) {
 			case 'b':
 				binary = 1;
@@ -225,6 +228,9 @@ int ip6tables_restore_main(int argc, char *argv[])
 			case 'n':
 				noflush = 1;
 				break;
+			case 'w':
+				wait = 1;
+				break;
 			case 'M':
 				xtables_modprobe_program = optarg;
 				break;
@@ -248,6 +254,12 @@ int ip6tables_restore_main(int argc, char *argv[])
 	}
 	else in = stdin;
 
+	if (!xtables_lock(wait)) {
+		fprintf(stderr, "Another app is currently holding the xtables lock. "
+			"Perhaps you want to use the -w option?\n");
+		exit(RESOURCE_PROBLEM);
+	}
+
 	/* Grab standard input. */
 	while (fgets(buffer, sizeof(buffer), in)) {
 		int ret = 0;
diff --git a/iptables/iptables-restore.c b/iptables/iptables-restore.c
index 8c942ff6..2009f732 100644
--- a/iptables/iptables-restore.c
+++ b/iptables/iptables-restore.c
@@ -12,6 +12,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include "iptables.h"
+#include "xshared.h"
 #include "xtables.h"
 #include "libiptc/libiptc.h"
 #include "iptables-multi.h"
@@ -22,7 +23,7 @@
 #define DEBUGP(x, args...)
 #endif
 
-static int binary = 0, counters = 0, verbose = 0, noflush = 0;
+static int binary = 0, counters = 0, verbose = 0, noflush = 0, wait = 0;
 
 /* Keeping track of external matches and targets.  */
 static const struct option options[] = {
@@ -32,6 +33,7 @@ static const struct option options[] = {
 	{.name = "test",     .has_arg = false, .val = 't'},
 	{.name = "help",     .has_arg = false, .val = 'h'},
 	{.name = "noflush",  .has_arg = false, .val = 'n'},
+	{.name = "wait",     .has_arg = false, .val = 'w'},
 	{.name = "modprobe", .has_arg = true,  .val = 'M'},
 	{.name = "table",    .has_arg = true,  .val = 'T'},
 	{NULL},
@@ -43,13 +45,14 @@ static void print_usage(const char *name, const char *version) __attribute__((no
 
 static void print_usage(const char *name, const char *version)
 {
-	fprintf(stderr, "Usage: %s [-b] [-c] [-v] [-t] [-h]\n"
+	fprintf(stderr, "Usage: %s [-b] [-c] [-v] [-t] [-h] [-w]\n"
 			"	   [ --binary ]\n"
 			"	   [ --counters ]\n"
 			"	   [ --verbose ]\n"
 			"	   [ --test ]\n"
 			"	   [ --help ]\n"
 			"	   [ --noflush ]\n"
+			"	   [ --wait ]\n"
 			"	   [ --table=<TABLE> ]\n"
 			"          [ --modprobe=<command>]\n", name);
 
@@ -204,7 +207,7 @@ iptables_restore_main(int argc, char *argv[])
 	init_extensions4();
 #endif
 
-	while ((c = getopt_long(argc, argv, "bcvthnM:T:", options, NULL)) != -1) {
+	while ((c = getopt_long(argc, argv, "bcvthnwM:T:", options, NULL)) != -1) {
 		switch (c) {
 			case 'b':
 				binary = 1;
@@ -225,6 +228,9 @@ iptables_restore_main(int argc, char *argv[])
 			case 'n':
 				noflush = 1;
 				break;
+			case 'w':
+				wait = 1;
+				break;
 			case 'M':
 				xtables_modprobe_program = optarg;
 				break;
@@ -248,6 +254,12 @@ iptables_restore_main(int argc, char *argv[])
 	}
 	else in = stdin;
 
+	if (!xtables_lock(wait)) {
+		fprintf(stderr, "Another app is currently holding the xtables lock. "
+			"Perhaps you want to use the -w option?\n");
+		exit(RESOURCE_PROBLEM);
+	}
+
 	/* Grab standard input. */
 	while (fgets(buffer, sizeof(buffer), in)) {
 		int ret = 0;
-- 
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