+struct secure_dirs {
+ int host_fd;
+ int cwd_fd;
+ int guest_fd;
+ int target_fd;
+};
+
+static inline int
+fchroot(int fd)
+{
+ if (fchdir(fd) == -1 || chroot(".") == -1)
+ return -1;
+ return 0;
+}
+
+static inline int
+restore_dirs(struct secure_dirs *dirs)
+{
+ if (dirs->host_fd != -1) {
+ if (fchroot(dirs->host_fd) == -1)
+ return -1;
+ if (close(dirs->host_fd) == -1)
+ return -1;
+ }
+ if (dirs->guest_fd != -1) {
+ if (close(dirs->guest_fd) == -1)
+ return -1;
+ }
+ if (dirs->target_fd != -1) {
+ if (close(dirs->target_fd) == -1)
+ return -1;
+ }
+ if (dirs->cwd_fd != -1) {
+ if (fchdir(dirs->cwd_fd) == -1)
+ return -1;
+ if (close(dirs->cwd_fd) == -1)
+ return -1;
+ }
+ return 0;
+}
+
+static inline int
+secure_chdir(struct secure_dirs *dirs, const char *guest, const char *target)
+{
+ dirs->host_fd = dirs->cwd_fd = dirs->guest_fd = dirs->target_fd = -1;
+
+ dirs->host_fd = open("/", O_RDONLY|O_DIRECTORY);
+ if (dirs->host_fd == -1)
+ return -1;
+
+ dirs->cwd_fd = open(".", O_RDONLY|O_DIRECTORY);
+ if (dirs->cwd_fd == -1)
+ return -1;
+
+ dirs->guest_fd = open(guest, O_RDONLY|O_DIRECTORY);
+ if (dirs->guest_fd == -1)
+ return -1;
+ if (fchroot(dirs->guest_fd) == -1)
+ return -1;
+
+ dirs->target_fd = open(target, O_RDONLY|O_DIRECTORY);
+ if (dirs->target_fd == -1)
+ return -1;
+
+ if (fchroot(dirs->host_fd) == -1 || close(dirs->host_fd) == -1)
+ return -1;
+ dirs->host_fd = -1;
+ if (close(dirs->guest_fd) == -1)
+ return -1;
+ dirs->guest_fd = -1;
+
+ if (fchdir(dirs->target_fd) == -1 || close(dirs->target_fd) == -1)
+ return -1;
+
+ return 0;
+}
+
+static PyObject *
+vserver_mount(PyObject *self, PyObject *args)
+{
+ const char *guest, *target, *source, *type, *data = NULL;
+ unsigned long flags = 0;
+ struct secure_dirs dirs;
+
+ if (!PyArg_ParseTuple(args, "ssss|ks", &source, &guest, &target, &type,
+ &flags, &data))
+ return NULL;
+
+ if (secure_chdir(&dirs, guest, target) == -1)
+ goto out;
+ if (mount(source, ".", type, flags, data) == -1)
+ goto out;
+ restore_dirs(&dirs);
+
+ return NONE;
+
+out:
+ restore_dirs(&dirs);
+ return PyErr_SetFromErrno(PyExc_OSError);
+}
+
+static PyObject *
+vserver_umount(PyObject *self, PyObject *args)
+{
+ const char *guest, *target;
+ int flags = 0;
+ char *path;
+ PyObject *ret;
+
+ if (!PyArg_ParseTuple(args, "ss|i", &guest, &target, &flags))
+ return NULL;
+
+ path = calloc(strlen(guest) + strlen(target) + 2, sizeof(char));
+ sprintf(path, "%s/%s", guest, target);
+ if (umount2(path, flags) == -1)
+ ret = PyErr_SetFromErrno(PyExc_OSError);
+ else
+ ret = NONE;
+ free(path);
+
+ return ret;
+}
+
+static PyObject *
+vserver_set_runlevel(PyObject *self, PyObject *args)
+{
+ const char *file;
+ int runlevel;
+ struct utmp ut;
+
+ if (!PyArg_ParseTuple(args, "si", &file, &runlevel))
+ return NULL;
+
+ utmpname(file);
+ setutent();
+ memset(&ut, 0, sizeof(ut));
+ ut.ut_type = RUN_LVL;
+ ut.ut_pid = ('#' << 8) + runlevel + '0';
+ pututline(&ut);
+ endutent();
+
+ return NONE;
+}
+