lib/namespace: fix fd leakage in non-error case

My previous patch 5950ba9 ("lib/namespace: don't leak fd in error case")
was a step in the wrong direction. Instead of closing the opened file
descriptor in error case only, follow a better approach here and close
the fd as soon as it is not used anymore. This way the inelegant goto
statements can be dropped, and the fd leak in non-error case is fixed as
well.

Fixes: 5950ba9 ("lib/namespace: don't leak fd in error case")
Signed-off-by: Phil Sutter <phil@nwl.cc>

diff --git a/lib/namespace.c b/lib/namespace.c
index 8197165259ccf0d052d7e3212a70eefe7a784cc0..30b513889e6e2423daefd749234260449db9bfbd 100644 (file)
--- a/lib/namespace.c
+++ b/lib/namespace.c
@@ -58,35 +58,34 @@ int netns_switch(char *name)
        if (setns(netns, CLONE_NEWNET) < 0) {
                fprintf(stderr, "setting the network namespace \"%s\" failed: %s\n",
                        name, strerror(errno));
-               goto fail_close;
+               close(netns);
+               return -1;
        }
+       close(netns);
 
        if (unshare(CLONE_NEWNS) < 0) {
                fprintf(stderr, "unshare failed: %s\n", strerror(errno));
-               goto fail_close;
+               return -1;
        }
        /* Don't let any mounts propagate back to the parent */
        if (mount("", "/", "none", MS_SLAVE | MS_REC, NULL)) {
                fprintf(stderr, "\"mount --make-rslave /\" failed: %s\n",
                        strerror(errno));
-               goto fail_close;
+               return -1;
        }
        /* Mount a version of /sys that describes the network namespace */
        if (umount2("/sys", MNT_DETACH) < 0) {
                fprintf(stderr, "umount of /sys failed: %s\n", strerror(errno));
-               goto fail_close;
+               return -1;
        }
        if (mount(name, "/sys", "sysfs", 0, NULL) < 0) {
                fprintf(stderr, "mount of /sys failed: %s\n",strerror(errno));
-               goto fail_close;
+               return -1;
        }
 
        /* Setup bind mounts for config files in /etc */
        bind_etc(name);
        return 0;
-fail_close:
-       close(netns);
-       return -1;
 }
 
 int netns_get_fd(const char *name)