VARLINK_PENDING_METHOD, \
VARLINK_PENDING_METHOD_MORE)
+typedef struct VarlinkJsonQueueItem VarlinkJsonQueueItem;
+
+/* A queued message we shall write into the socket, along with the file descriptors to send at the same
+ * time. This queue item binds them together so that message/fd boundaries are maintained throughout the
+ * whole pipeline. */
+struct VarlinkJsonQueueItem {
+ LIST_FIELDS(VarlinkJsonQueueItem, queue);
+ JsonVariant *data;
+ size_t n_fds;
+ int fds[];
+};
+
struct Varlink {
unsigned n_ref;
size_t output_buffer_index;
size_t output_buffer_size;
+ int *input_fds; /* file descriptors associated with the data in input_buffer (for fd passing) */
+ size_t n_input_fds;
+
+ int *output_fds; /* file descriptors associated with the data in output_buffer (for fd passing) */
+ size_t n_output_fds;
+
+ /* Further messages to output not yet formatted into text, and thus not included in output_buffer
+ * yet. We keep them separate from output_buffer, to not violate fd message boundaries: we want that
+ * each fd that is sent is associated with its fds, and that fds cannot be accidentally associated
+ * with preceeding or following messages. */
+ LIST_HEAD(VarlinkJsonQueueItem, output_queue);
+ VarlinkJsonQueueItem *output_queue_tail;
+
+ /* The fds to associate with the next message that is about to be enqueued. The user first pushes the
+ * fds it intends to send via varlink_push_fd() into this queue, and then once the message data is
+ * submitted we'll combine the fds and the message data into one. */
+ int *pushed_fds;
+ size_t n_pushed_fds;
+
VarlinkReply reply_callback;
JsonVariant *current;
bool prefer_read_write:1;
bool got_pollhup:1;
+ bool allow_fd_passing_input:1;
+ bool allow_fd_passing_output:1;
+
+ int af; /* address family if socket; AF_UNSPEC if not socket; negative if not known */
+
usec_t timestamp;
usec_t timeout;
#define varlink_server_log(s, fmt, ...) \
log_debug("%s: " fmt, varlink_server_description(s), ##__VA_ARGS__)
+static int varlink_format_queue(Varlink *v);
+
static inline const char *varlink_description(Varlink *v) {
return (v ? v->description : NULL) ?: "varlink";
}
return (s ? s->description : NULL) ?: "varlink";
}
+static VarlinkJsonQueueItem *varlink_json_queue_item_free(VarlinkJsonQueueItem *q) {
+ if (!q)
+ return NULL;
+
+ json_variant_unref(q->data);
+ close_many(q->fds, q->n_fds);
+
+ return mfree(q);
+}
+
+static VarlinkJsonQueueItem *varlink_json_queue_item_new(JsonVariant *m, const int fds[], size_t n_fds) {
+ VarlinkJsonQueueItem *q;
+
+ assert(m);
+ assert(fds || n_fds == 0);
+
+ q = malloc(offsetof(VarlinkJsonQueueItem, fds) + sizeof(int) * n_fds);
+ if (!q)
+ return NULL;
+
+ *q = (VarlinkJsonQueueItem) {
+ .data = json_variant_ref(m),
+ .n_fds = n_fds,
+ };
+
+ memcpy_safe(q->fds, fds, n_fds * sizeof(int));
+
+ return TAKE_PTR(q);
+}
+
static void varlink_set_state(Varlink *v, VarlinkState state) {
assert(v);
assert(state >= 0 && state < _VARLINK_STATE_MAX);
.ucred = UCRED_INVALID,
.timestamp = USEC_INFINITY,
- .timeout = VARLINK_DEFAULT_TIMEOUT_USEC
+ .timeout = VARLINK_DEFAULT_TIMEOUT_USEC,
+
+ .af = -1,
};
*ret = v;
return log_debug_errno(errno, "Failed to create AF_UNIX socket: %m");
v->fd = fd_move_above_stdio(v->fd);
+ v->af = AF_UNIX;
r = sockaddr_un_set_path(&sockaddr.un, address);
if (r < 0) {
return log_debug_errno(r, "Failed to create varlink object: %m");
v->fd = fd;
+ v->af = -1,
varlink_set_state(v, VARLINK_IDLE_CLIENT);
/* Note that if this function is called we assume the passed socket (if it is one) is already
/* Clears the currently processed incoming message */
v->current = json_variant_unref(v->current);
+
+ close_many(v->input_fds, v->n_input_fds);
+ v->input_fds = mfree(v->input_fds);
+ v->n_input_fds = 0;
}
static void varlink_clear(Varlink *v) {
v->fd = safe_close(v->fd);
+ varlink_clear_current(v);
+
v->input_buffer = mfree(v->input_buffer);
v->output_buffer = mfree(v->output_buffer);
varlink_clear_current(v);
+ close_many(v->output_fds, v->n_output_fds);
+ v->output_fds = mfree(v->output_fds);
+ v->n_output_fds = 0;
+
+ close_many(v->pushed_fds, v->n_pushed_fds);
+ v->pushed_fds = mfree(v->pushed_fds);
+ v->n_pushed_fds = 0;
+
+ while (v->output_queue) {
+ VarlinkJsonQueueItem *q = v->output_queue;
+
+ LIST_REMOVE(queue, v->output_queue, q);
+ varlink_json_queue_item_free(q);
+ }
+ v->output_queue_tail = NULL;
+
v->event = sd_event_unref(v->event);
}
static int varlink_write(Varlink *v) {
ssize_t n;
+ int r;
assert(v);
if (v->connecting) /* Writing while we are still wait for a non-blocking connect() to complete will
* result in ENOTCONN, hence exit early here */
return 0;
- if (v->output_buffer_size == 0)
- return 0;
if (v->write_disconnected)
return 0;
+ /* If needed let's convert some output queue json variants into text form */
+ r = varlink_format_queue(v);
+ if (r < 0)
+ return r;
+
+ if (v->output_buffer_size == 0)
+ return 0;
+
assert(v->fd >= 0);
- /* We generally prefer recv()/send() (mostly because of MSG_NOSIGNAL) but also want to be compatible
- * with non-socket IO, hence fall back automatically.
- *
- * Use a local variable to help gcc figure out that we set 'n' in all cases. */
- bool prefer_write = v->prefer_read_write;
- if (!prefer_write) {
- n = send(v->fd, v->output_buffer + v->output_buffer_index, v->output_buffer_size, MSG_DONTWAIT|MSG_NOSIGNAL);
- if (n < 0 && errno == ENOTSOCK)
- prefer_write = v->prefer_read_write = true;
+ if (v->n_output_fds > 0) { /* If we shall send fds along, we must use sendmsg() */
+ struct iovec iov = {
+ .iov_base = v->output_buffer + v->output_buffer_index,
+ .iov_len = v->output_buffer_size,
+ };
+ struct msghdr mh = {
+ .msg_iov = &iov,
+ .msg_iovlen = 1,
+ .msg_controllen = CMSG_SPACE(sizeof(int) * v->n_output_fds),
+ };
+
+ mh.msg_control = alloca0(mh.msg_controllen);
+
+ struct cmsghdr *control = CMSG_FIRSTHDR(&mh);
+ control->cmsg_len = CMSG_LEN(sizeof(int) * v->n_output_fds);
+ control->cmsg_level = SOL_SOCKET;
+ control->cmsg_type = SCM_RIGHTS;
+ memcpy(CMSG_DATA(control), v->output_fds, sizeof(int) * v->n_output_fds);
+
+ n = sendmsg(v->fd, &mh, MSG_DONTWAIT|MSG_NOSIGNAL);
+ } else {
+ /* We generally prefer recv()/send() (mostly because of MSG_NOSIGNAL) but also want to be compatible
+ * with non-socket IO, hence fall back automatically.
+ *
+ * Use a local variable to help gcc figure out that we set 'n' in all cases. */
+ bool prefer_write = v->prefer_read_write;
+ if (!prefer_write) {
+ n = send(v->fd, v->output_buffer + v->output_buffer_index, v->output_buffer_size, MSG_DONTWAIT|MSG_NOSIGNAL);
+ if (n < 0 && errno == ENOTSOCK)
+ prefer_write = v->prefer_read_write = true;
+ }
+ if (prefer_write)
+ n = write(v->fd, v->output_buffer + v->output_buffer_index, v->output_buffer_size);
}
- if (prefer_write)
- n = write(v->fd, v->output_buffer + v->output_buffer_index, v->output_buffer_size);
if (n < 0) {
if (errno == EAGAIN)
return 0;
else
v->output_buffer_index += n;
+ close_many(v->output_fds, v->n_output_fds);
+ v->n_output_fds = 0;
+
v->timestamp = now(CLOCK_MONOTONIC);
return 1;
}
+#define VARLINK_FDS_MAX (16U*1024U)
+
static int varlink_read(Varlink *v) {
+ CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(int) * VARLINK_FDS_MAX)) control;
+ struct iovec iov;
+ struct msghdr mh;
size_t rs;
ssize_t n;
+ void *p;
assert(v);
}
}
+ p = v->input_buffer + v->input_buffer_index + v->input_buffer_size;
rs = MALLOC_SIZEOF_SAFE(v->input_buffer) - (v->input_buffer_index + v->input_buffer_size);
- bool prefer_read = v->prefer_read_write;
- if (!prefer_read) {
- n = recv(v->fd, v->input_buffer + v->input_buffer_index + v->input_buffer_size, rs, MSG_DONTWAIT);
- if (n < 0 && errno == ENOTSOCK)
- prefer_read = v->prefer_read_write = true;
+ if (v->allow_fd_passing_input) {
+ iov = (struct iovec) {
+ .iov_base = p,
+ .iov_len = rs,
+ };
+ mh = (struct msghdr) {
+ .msg_iov = &iov,
+ .msg_iovlen = 1,
+ .msg_control = &control,
+ .msg_controllen = sizeof(control),
+ };
+ n = recvmsg_safe(v->fd, &mh, MSG_DONTWAIT|MSG_CMSG_CLOEXEC);
+ } else {
+ bool prefer_read = v->prefer_read_write;
+ if (!prefer_read) {
+ n = recv(v->fd, p, rs, MSG_DONTWAIT);
+ if (n < 0 && errno == ENOTSOCK)
+ prefer_read = v->prefer_read_write = true;
+ }
+ if (prefer_read)
+ n = read(v->fd, p, rs);
}
- if (prefer_read)
- n = read(v->fd, v->input_buffer + v->input_buffer_index + v->input_buffer_size, rs);
if (n < 0) {
if (errno == EAGAIN)
return 0;
return -errno;
}
if (n == 0) { /* EOF */
+
+ if (v->allow_fd_passing_input)
+ cmsg_close_all(&mh);
+
v->read_disconnected = true;
return 1;
}
+ if (v->allow_fd_passing_input) {
+ struct cmsghdr* cmsg;
+
+ cmsg = cmsg_find(&mh, SOL_SOCKET, SCM_RIGHTS, (socklen_t) -1);
+ if (cmsg) {
+ size_t add;
+
+ /* We only allow file descriptors to be passed along with the first byte of a
+ * message. If they are passed with any other byte this is a protocol violation. */
+ if (v->input_buffer_size != 0) {
+ cmsg_close_all(&mh);
+ return -EPROTO;
+ }
+
+ add = (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int);
+ if (add > INT_MAX - v->n_input_fds) {
+ cmsg_close_all(&mh);
+ return -EBADF;
+ }
+
+ if (!GREEDY_REALLOC(v->input_fds, v->n_input_fds + add)) {
+ cmsg_close_all(&mh);
+ return -ENOMEM;
+ }
+
+ memcpy_safe(v->input_fds + v->n_input_fds, CMSG_TYPED_DATA(cmsg, int), add * sizeof(int));
+ v->n_input_fds += add;
+ }
+ }
+
v->input_buffer_size += n;
v->input_buffer_unscanned += n;
return varlink_close_unref(v);
}
-static int varlink_enqueue_json(Varlink *v, JsonVariant *m) {
+static int varlink_format_json(Varlink *v, JsonVariant *m) {
_cleanup_free_ char *text = NULL;
int r;
return 0;
}
+static int varlink_enqueue_json(Varlink *v, JsonVariant *m) {
+ VarlinkJsonQueueItem *q;
+
+ assert(v);
+ assert(m);
+
+ /* If ther are no file descriptors to be queued and no queue entries yet we can shortcut things and
+ * append this entry directly to the output buffer */
+ if (v->n_pushed_fds == 0 && !v->output_queue)
+ return varlink_format_json(v, m);
+
+ /* Otherwise add a queue entry for this */
+ q = varlink_json_queue_item_new(m, v->pushed_fds, v->n_pushed_fds);
+ if (!q)
+ return -ENOMEM;
+
+ v->n_pushed_fds = 0; /* fds now belong to the queue entry */
+
+ LIST_INSERT_AFTER(queue, v->output_queue, v->output_queue_tail, q);
+ v->output_queue_tail = q;
+ return 0;
+}
+
+static int varlink_format_queue(Varlink *v) {
+ int r;
+
+ assert(v);
+
+ /* Takes entries out of the output queue and formats them into the output buffer. But only if this
+ * would not corrupt our fd message boundaries */
+
+ while (v->output_queue) {
+ _cleanup_free_ int *array = NULL;
+ VarlinkJsonQueueItem *q = v->output_queue;
+
+ if (v->n_output_fds > 0) /* unwritten fds? if we'd add more we'd corrupt the fd message boundaries, hence wait */
+ return 0;
+
+ if (q->n_fds > 0) {
+ array = newdup(int, q->fds, q->n_fds);
+ if (!array)
+ return -ENOMEM;
+ }
+
+ r = varlink_format_json(v, q->data);
+ if (r < 0)
+ return r;
+
+ /* Take possession of the queue element's fds */
+ free(v->output_fds);
+ v->output_fds = TAKE_PTR(array);
+ v->n_output_fds = q->n_fds;
+ q->n_fds = 0;
+
+ LIST_REMOVE(queue, v->output_queue, q);
+ if (!v->output_queue)
+ v->output_queue_tail = NULL;
+
+ varlink_json_queue_item_free(q);
+ }
+
+ return 0;
+}
+
int varlink_send(Varlink *v, const char *method, JsonVariant *parameters) {
_cleanup_(json_variant_unrefp) JsonVariant *m = NULL;
int r;
assert(v->n_pending == 0); /* n_pending can't be > 0 if we are in VARLINK_IDLE_CLIENT state */
+ /* If there was still a reply pinned from a previous call, now it's the time to get rid of it, so
+ * that we can assign a new reply shortly. */
varlink_clear_current(v);
r = varlink_sanitize_parameters(¶meters);
VARLINK_PENDING_METHOD, VARLINK_PENDING_METHOD_MORE))
return varlink_log_errno(v, SYNTHETIC_ERRNO(EBUSY), "Connection busy.");
+ /* Reset the list of pushed file descriptors before sending an error reply. We do this here to
+ * simplify code that puts together a complex reply message with fds, and half-way something
+ * fails. In that case the pushed fds need to be flushed out again. Under the assumption that it
+ * never makes sense to send fds along with errors we simply flush them out here beforehand, so that
+ * the callers don't need to do this explicitly. */
+ varlink_reset_fds(v);
+
r = varlink_sanitize_parameters(¶meters);
if (r < 0)
return varlink_log_errno(v, r, "Failed to sanitize parameters: %m");
return v->event;
}
+int varlink_push_fd(Varlink *v, int fd) {
+ int i;
+
+ assert_return(v, -EINVAL);
+ assert_return(fd >= 0, -EBADF);
+
+ /* Takes an fd to send along with the *next* varlink message sent via this varlink connection. This
+ * takes ownership of the specified fd. Use varlink_dup_fd() below to duplicate the fd first. */
+
+ if (!v->allow_fd_passing_output)
+ return -EPERM;
+
+ if (v->n_pushed_fds >= INT_MAX)
+ return -ENOMEM;
+
+ if (!GREEDY_REALLOC(v->pushed_fds, v->n_pushed_fds + 1))
+ return -ENOMEM;
+
+ i = (int) v->n_pushed_fds;
+ v->pushed_fds[v->n_pushed_fds++] = fd;
+ return i;
+}
+
+int varlink_dup_fd(Varlink *v, int fd) {
+ _cleanup_close_ int dp = -1;
+ int r;
+
+ assert_return(v, -EINVAL);
+ assert_return(fd >= 0, -EBADF);
+
+ /* Like varlink_push_fd() but duplicates the specified fd instead of taking possession of it */
+
+ dp = fcntl(fd, F_DUPFD_CLOEXEC, 3);
+ if (dp < 0)
+ return -errno;
+
+ r = varlink_push_fd(v, dp);
+ if (r < 0)
+ return r;
+
+ TAKE_FD(dp);
+ return r;
+}
+
+int varlink_reset_fds(Varlink *v) {
+ assert_return(v, -EINVAL);
+
+ /* Closes all currently pending fds to send. This may be used whenever the caller is in the process
+ * of putting together a message with fds, and then eventually something fails and they need to
+ * rollback the fds. Note that this is implicitly called whenever an error reply is sent, see above. */
+
+ close_many(v->output_fds, v->n_output_fds);
+ v->n_output_fds = 0;
+ return 0;
+}
+
+int varlink_peek_fd(Varlink *v, size_t i) {
+ assert_return(v, -EINVAL);
+
+ /* Returns one of the file descriptors that were received along witht the current message. This does
+ * not duplicate the fd nor invalidate it, it hence remains in our possession. */
+
+ if (!v->allow_fd_passing_input)
+ return -EPERM;
+
+ if (i >= v->n_input_fds)
+ return -ENXIO;
+
+ return v->input_fds[i];
+}
+
+int varlink_take_fd(Varlink *v, size_t i) {
+ assert_return(v, -EINVAL);
+
+ /* Similar to varlink_peek_fd() but the file descriptor's ownership is passed to the caller, and
+ * we'll invalidate the reference to it under our possession. If called twice in a row will return
+ * -EBADF */
+
+ if (!v->allow_fd_passing_input)
+ return -EPERM;
+
+ if (i >= v->n_input_fds)
+ return -ENXIO;
+
+ return TAKE_FD(v->input_fds[i]);
+}
+
+static int verify_unix_socket(Varlink *v) {
+ assert(v);
+
+ if (v->af < 0) {
+ struct stat st;
+
+ if (fstat(v->fd, &st) < 0)
+ return -errno;
+ if (!S_ISSOCK(st.st_mode)) {
+ v->af = AF_UNSPEC;
+ return -ENOTSOCK;
+ }
+
+ v->af = socket_get_family(v->fd);
+ if (v->af < 0)
+ return v->af;
+ }
+
+ return v->af == AF_UNIX ? 0 : -ENOMEDIUM;
+}
+
+int varlink_set_allow_fd_passing_input(Varlink *v, bool b) {
+ int r;
+
+ assert_return(v, -EINVAL);
+
+ if (v->allow_fd_passing_input == b)
+ return 0;
+
+ if (!b) {
+ v->allow_fd_passing_input = false;
+ return 1;
+ }
+
+ r = verify_unix_socket(v);
+ if (r < 0)
+ return r;
+
+ v->allow_fd_passing_input = true;
+ return 0;
+}
+
+int varlink_set_allow_fd_passing_output(Varlink *v, bool b) {
+ int r;
+
+ assert_return(v, -EINVAL);
+
+ if (v->allow_fd_passing_output == b)
+ return 0;
+
+ if (!b) {
+ v->allow_fd_passing_output = false;
+ return 1;
+ }
+
+ r = verify_unix_socket(v);
+ if (r < 0)
+ return r;
+
+ v->allow_fd_passing_output = true;
+ return 0;
+}
+
int varlink_server_new(VarlinkServer **ret, VarlinkServerFlags flags) {
VarlinkServer *s;
projects / thirdparty / systemd.git / commitdiff
