Patch from Mike Snitzer to fix return codes.

"I have a need to _really_ know if the interface was properly configured
via ifup so I made busybox's ifupdown pass the return codes through rather
than dropping them on the floor."

"All the functions in ifupdown.c return 1 on success and 0 on failure
(which happens to the opposite of standard practices but whatever).
So it is important for all these functions to not blindly return 1."

"The problem with blindly returning ret, even if it is != 1, is the
callers expect a 0 or 1 and accumulate the return codes.  So a function that
makes 3 calls to execute will have a value of 3 accumulated.  That value
of 1 (success) was almost always returned even if 1 of the commands in the
command sequence failed.  The attached patch fixes the lack of checking
to verify thar result == expected_reult."

networking/ifupdown.c

@@ -27,6 +27,8 @@
  *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  */
 
+/* TODO: standardise execute() return codes to return 0 for success and 1 for failure */
+
 #include <sys/stat.h>
 #include <sys/utsname.h>
 #include <sys/wait.h>
@@ -347,6 +349,9 @@ static int execute(char *command, struct interface_defn_t *ifd, execfn *exec)
 	ret = (*exec) (out);
 
 	free(out);
+	if (ret != 1) {
+		return(0);
+	}
 	return(1);
 }
 
@@ -390,7 +395,7 @@ static int loopback_up6(struct interface_defn_t *ifd, execfn *exec)
 	int result;
 	result =execute("ip addr add ::1 dev %iface%", ifd, exec);
 	result += execute("ip link set %iface% up", ifd, exec);
-	return( result);
+	return ((result == 2) ? 2 : 0);
 #else
 	return( execute("ifconfig %iface% add ::1", ifd, exec));
 #endif
@@ -417,7 +422,7 @@ static int static_up6(struct interface_defn_t *ifd, execfn *exec)
 	result += execute("ifconfig %iface% add %address%/%netmask%", ifd, exec);
 	result += execute("[[ route -A inet6 add ::/0 gw %gateway% ]]", ifd, exec);
 #endif
-	return( result);
+	return ((result == 3) ? 3 : 0);
 }
 
 static int static_down6(struct interface_defn_t *ifd, execfn *exec)
@@ -438,7 +443,7 @@ static int v4tunnel_up(struct interface_defn_t *ifd, execfn *exec)
 	result += execute("ip link set %iface% up", ifd, exec);
 	result += execute("ip addr add %address%/%netmask% dev %iface%", ifd, exec);
 	result += execute("[[ ip route add ::/0 via %gateway% ]]", ifd, exec);
-	return( result);
+	return ((result == 4) ? 4 : 0);
 }
 
 static int v4tunnel_down(struct interface_defn_t * ifd, execfn * exec)
@@ -469,7 +474,7 @@ static int loopback_up(struct interface_defn_t *ifd, execfn *exec)
 	int result;
 	result = execute("ip addr add 127.0.0.1/8 dev %iface%", ifd, exec);
 	result += execute("ip link set %iface% up", ifd, exec);
-	return(result);
+	return ((result == 2) ? 2 : 0);
 #else
 	return( execute("ifconfig %iface% 127.0.0.1 up", ifd, exec));
 #endif
@@ -481,7 +486,7 @@ static int loopback_down(struct interface_defn_t *ifd, execfn *exec)
 	int result;
 	result = execute("ip addr flush dev %iface%", ifd, exec);
 	result += execute("ip link set %iface% down", ifd, exec);
-	return(result);
+	return ((result == 2) ? 2 : 0);
 #else
 	return( execute("ifconfig %iface% 127.0.0.1 down", ifd, exec));
 #endif
@@ -495,14 +500,15 @@ static int static_up(struct interface_defn_t *ifd, execfn *exec)
 			"dev %iface% [[peer %pointopoint%]] [[label %label%]]", ifd, exec);
 	result += execute("ip link set [[mtu %mtu%]] [[address %hwaddress%]] %iface% up", ifd, exec);
 	result += execute("[[ ip route add default via %gateway% dev %iface% ]]", ifd, exec);
+	return ((result == 3) ? 3 : 0);
 #else
 	result = execute("ifconfig %iface% %address% netmask %netmask% "
 				"[[broadcast %broadcast%]] 	[[pointopoint %pointopoint%]] "
 				"[[media %media%]] [[mtu %mtu%]] 	[[hw %hwaddress%]] up",
 				ifd, exec);
 	result += execute("[[ route add default gw %gateway% %iface% ]]", ifd, exec);
+	return ((result == 2) ? 2 : 0);
 #endif
-	return(result);
 }
 
 static int static_down(struct interface_defn_t *ifd, execfn *exec)
@@ -515,7 +521,7 @@ static int static_down(struct interface_defn_t *ifd, execfn *exec)
 	result = execute("[[ route del default gw %gateway% %iface% ]]", ifd, exec);
 	result += execute("ifconfig %iface% down", ifd, exec);
 #endif
-	return(result);
+	return ((result == 2) ? 2 : 0);
 }
 
 static int execable(char *program)
@@ -562,7 +568,7 @@ static int dhcp_down(struct interface_defn_t *ifd, execfn *exec)
 	} else if (execable("/sbin/pump")) {
 		result = execute("pump -i %iface% -k", ifd, exec);
 	} else if (execable("/sbin/dhclient")) {
-		execute("kill -9 `cat /var/run/dhclient.%iface%.pid` 2>/dev/null", ifd, exec);
+		result = execute("kill -9 `cat /var/run/dhclient.%iface%.pid` 2>/dev/null", ifd, exec);
 	} else if (execable("/sbin/dhcpcd")) {
 		result = execute("dhcpcd -k %iface%", ifd, exec);
 	}
@@ -1033,9 +1039,10 @@ static int execute_all(struct interface_defn_t *ifd, execfn *exec, const char *o
 	}
 
 	bb_xasprintf(&buf, "run-parts /etc/network/if-%s.d", opt);
-	(*exec)(buf);
-
-	return (1);
+	if ((*exec)(buf) != 1) {
+		return 0;
+	}
+	return 1;
 }
 
 static int check(char *str) {
@@ -1198,6 +1205,7 @@ extern int ifupdown_main(int argc, char **argv)
 #endif
 	int do_all = 0;
 	int force = 0;
+	int any_failures = 0;
 	int i;
 
 	if (bb_applet_name[2] == 'u') {
@@ -1312,6 +1320,7 @@ extern int ifupdown_main(int argc, char **argv)
 		char *liface;
 		char *pch;
 		int okay = 0;
+		int cmds_ret;
 
 		iface = strdup(target_list->data);
 		target_list = target_list->link;
@@ -1374,9 +1383,13 @@ extern int ifupdown_main(int argc, char **argv)
 				debug_noise("\nConfiguring interface %s (%s)\n", liface, currif->address_family->name);
 
 				/* Call the cmds function pointer, does either iface_up() or iface_down() */
-				if (cmds(currif) == -1) {
+				cmds_ret = cmds(currif);
+				if (cmds_ret == -1) {
 					bb_error_msg("Don't seem to have all the variables for %s/%s.",
 							liface, currif->address_family->name);
+					any_failures += 1;
+				} else if (cmds_ret == 0) {
+					any_failures += 1;
 				}
 
 				currif->iface = oldiface;
@@ -1389,6 +1402,7 @@ extern int ifupdown_main(int argc, char **argv)
 
 		if (!okay && !force) {
 			bb_error_msg("Ignoring unknown interface %s", liface);
+			any_failures += 1;
 		} else {
 			llist_t *iface_state = find_iface_state(state_list, iface);
 
@@ -1448,5 +1462,7 @@ extern int ifupdown_main(int argc, char **argv)
 		state_fp = NULL;
 	}
 
+	if (any_failures)
+		return 1;
 	return 0;
 }