networking: log output from 'ifup -a', run 'ifdown -a' interactively

We've been discussing, over the years, that we'd like to have an easier
way to debug bringup with Finit.  Network bringup is one such case where
it's hard to debug if/what you've misspelled in /etc/network/interfaces

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

src/helpers.c

@@ -30,6 +30,7 @@
 #include <net/if.h>
 #include <netinet/in.h>
 #include <stdarg.h>
+#include <sysexits.h>
 #include <sys/ioctl.h>
 #ifdef _LIBITE_LITE
 # include <libite/lite.h>
@@ -40,6 +41,7 @@
 #include "finit.h"
 #include "helpers.h"
 #include "private.h"
+#include "sig.h"
 #include "util.h"
 #include "utmp-api.h"
 
@@ -498,17 +500,35 @@ void networking(int updown)
 	if (fexist("/etc/network/interfaces")) {
 		pid_t pid;
 
+		if (!updown) {
+			run_interactive("ifdown -a", "Stopping networking");
+			goto done;
+		}
+
 		pid = fork();
 		if (pid == 0) {
-			if (updown)
-				run("ifup -a");
-			else
-				run("ifdown -a");
-			_exit(0);
+			int rc = EX_OSERR;
+			FILE *pp;
+
+			setsid();
+			sig_unblock();
+
+			pp = popen("ifup -a 2>&1", "r");
+			if (pp) {
+				char buf[256];
+
+				while (fgets(buf, sizeof(buf), pp))
+					logit(LOG_NOTICE, "network: %s", buf);
+
+				rc = pclose(pp);
+			}
+
+			_exit(rc);
 		}
 		cgroup_service("network", pid, NULL);
+		print(pid > 0 ? 0 : 1, "Bringing up network interfaces ...");
 
-		print(pid > 0 ? 0 : 1, "%s networking", updown ? "Starting" : "Stopping");
+		goto done;
 	}
 
 fallback: