initial commit

setns.c

@@ -0,0 +1,31 @@
+#define _GNU_SOURCE
+#include <fcntl.h>
+#include <sched.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+#define errExit(msg)    do { perror(msg); exit(EXIT_FAILURE); \
+	} while (0)
+
+int
+main(int argc, char *argv[])
+{
+	int fd;
+
+	if (argc < 3) {
+		fprintf(stderr, "%s /proc/PID/ns/FILE cmd args...\n", argv[0]);
+		exit(EXIT_FAILURE);
+	}
+
+	fd = open(argv[1], O_RDONLY);   /* Get descriptor for namespace */
+	if (fd == -1)
+		errExit("open");
+
+	//if (setns(fd, CLONE_NEWNS) == -1)
+	if (setns(fd, 0) == -1)         /* Join that namespace */
+		errExit("setns");
+
+	execvp(argv[2], &argv[2]);      /* Execute a command in namespace */
+	errExit("execvp");
+}