X-Git-Url: https://git.wh0rd.org/?p=home.git;a=blobdiff_plain;f=vunshare.c;h=96fe7a35b677a3b24c6d7baae6222160591730d6;hp=274eebcd9dc87e05008d3f57ff780012b1b2fb90;hb=HEAD;hpb=ce7f5e52754ca16cf3140fe3100c92d6904e5757

diff --git a/vunshare.c b/vunshare.c
index 274eebc..96fe7a3 100644
--- a/vunshare.c
+++ b/vunshare.c
@@ -4,7 +4,6 @@
  */
 
 /* TODO:
- * - Add userns support.
  * - Make pidns init optional.
  * - Make setproctitle nicer and include program argv[0].
  * - Set up prctl(PR_SET_PDEATHSIG).
@@ -51,14 +50,19 @@ static void unshare_net(void)
 	if (!vunshare(CLONE_NEWNET))
 		return;
 
-	int sock = socket(AF_LOCAL, SOCK_DGRAM|SOCK_CLOEXEC, 0);
+	int sock;
 	struct ifreq ifr;
 
+	sock = socket(AF_LOCAL, SOCK_DGRAM|SOCK_CLOEXEC, 0);
+	if (sock < 0)
+		err(1, "socket(AF_LOCAL) failed");
+
 	/* Equiv of `ip link set up lo`.  Kernel will assign 127.0.0.1 for us. */
 	strcpy(ifr.ifr_name, "lo");
 	if (ioctl(sock, SIOCGIFFLAGS, &ifr) < 0)
 		err(1, "ioctl(SIOCGIFFLAGS) failed");
-	strcpy(ifr.ifr_name, "lo");
+
+	/* The kernel preserves ifr.ifr_name for use. */
 	ifr.ifr_flags |= IFF_UP | IFF_RUNNING;
 	if (ioctl(sock, SIOCSIFFLAGS, &ifr) < 0)
 		err(1, "ioctl(SIOCSIFFLAGS) failed");
@@ -190,7 +194,7 @@ static void setup_signal_handler(pid_t pid)
 
 	child_pid = pid;
 
-	for (i = 1; i < SIGUNUSED; ++i)
+	for (i = 1; i < SIGRTMIN; ++i)
 		if (sigaction(i, &sa, NULL) && errno != EINVAL)
 			fprintf(stderr, "sigaction(%i) failed: %s\n", i, strerror(errno));
 	for (i = SIGRTMIN; i <= SIGRTMAX; ++i)
@@ -283,7 +287,18 @@ static const struct option opts[] = {
 
 static void usage(void)
 {
-	puts("Usage: unshare [options] <program>");
+	puts(
+		"Usage: unshare [options] <program>\n"
+		"\n"
+		"Options: [DimnpuU]\n"
+		"  -i   Use IPC namespaces\n"
+		"  -m   Use mount namespaces\n"
+		"  -n   Use net namespaces\n"
+		"  -p   Use pid namespaces\n"
+		"  -u   Use UTS namespaces\n"
+		"  -U   Use user namespaces\n"
+		"  -D   Daemonize program"
+	);
 	exit(EX_USAGE);
 }