iproute2: Fail "ip netns add" on existing network namespaces.
Use O_EXCL so that we only create and mount a new network namespace
if there is no chance an existing network namespace is present.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
diff --git a/ip/ipnetns.c b/ip/ipnetns.c
index dff3497..e41a598 100644
--- a/ip/ipnetns.c
+++ b/ip/ipnetns.c
@@ -41,16 +41,6 @@
#endif /* HAVE_SETNS */
-static int touch(const char *path, mode_t mode)
-{
- int fd;
- fd = open(path, O_RDONLY|O_CREAT, mode);
- if (fd < 0)
- return -1;
- close(fd);
- return 0;
-}
-
static void usage(void) __attribute__((noreturn));
static void usage(void)
@@ -214,6 +204,7 @@
*/
char netns_path[MAXPATHLEN];
const char *name;
+ int fd;
if (argc < 1) {
fprintf(stderr, "No netns name specified\n");
@@ -227,11 +218,13 @@
mkdir(NETNS_RUN_DIR, S_IRWXU|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH);
/* Create the filesystem state */
- if (touch(netns_path, 0) < 0) {
+ fd = open(netns_path, O_RDONLY|O_CREAT|O_EXCL, 0);
+ if (fd < 0) {
fprintf(stderr, "Could not create %s: %s\n",
netns_path, strerror(errno));
- goto out_delete;
+ return -1;
}
+ close(fd);
if (unshare(CLONE_NEWNET) < 0) {
fprintf(stderr, "Failed to create a new network namespace: %s\n",
strerror(errno));