Add unshare(1)

No manpage yet.

Makefile

@@ -26,7 +26,8 @@ SRC += \
 	reboot.c            \
 	rmmod.c             \
 	swapoff.c           \
-	swapon.c
+	swapon.c            \
+	unshare.c
 endif
 
 OBJ = $(SRC:.c=.o) $(LIB)

unshare.c

@@ -0,0 +1,53 @@
+/* See LICENSE file for copyright and license details. */
+#include <sched.h>
+#include <errno.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <string.h>
+#include "util.h"
+
+static void
+usage(void)
+{
+	eprintf("usage: %s program [args]\n", argv0);
+}
+
+int
+main(int argc, char *argv[])
+{
+	int flags = 0;
+
+	ARGBEGIN {
+	case 'm':
+		flags |= CLONE_NEWNS;
+		break;
+	case 'u':
+		flags |= CLONE_NEWUTS;
+		break;
+	case 'i':
+		flags |= CLONE_NEWIPC;
+		break;
+	case 'n':
+		flags |= CLONE_NEWNET;
+		break;
+	case 'p':
+		flags |= CLONE_NEWPID;
+		break;
+	case 'U':
+		flags |= CLONE_NEWUSER;
+		break;
+	default:
+		usage();
+	} ARGEND;
+
+	if (argc < 1)
+		usage();
+
+	if (unshare(flags) < 0)
+		eprintf("unshare:");
+
+	if (execvp(argv[0], argv) < 0)
+		eprintf("execvp:");
+
+	return 0;
+}