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[thirdparty/systemd.git] / src / shared / varlink.c
1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
2
3 #include <malloc.h>
4 #include <sys/poll.h>
5
6 #include "alloc-util.h"
7 #include "errno-util.h"
8 #include "fd-util.h"
9 #include "hashmap.h"
10 #include "io-util.h"
11 #include "list.h"
12 #include "process-util.h"
13 #include "selinux-util.h"
14 #include "set.h"
15 #include "socket-util.h"
16 #include "string-table.h"
17 #include "string-util.h"
18 #include "strv.h"
19 #include "time-util.h"
20 #include "umask-util.h"
21 #include "user-util.h"
22 #include "varlink.h"
23
24 #define VARLINK_DEFAULT_CONNECTIONS_MAX 4096U
25 #define VARLINK_DEFAULT_CONNECTIONS_PER_UID_MAX 1024U
26
27 #define VARLINK_DEFAULT_TIMEOUT_USEC (45U*USEC_PER_SEC)
28 #define VARLINK_BUFFER_MAX (16U*1024U*1024U)
29 #define VARLINK_READ_SIZE (64U*1024U)
30
31 typedef enum VarlinkState {
32 /* Client side states */
33 VARLINK_IDLE_CLIENT,
34 VARLINK_AWAITING_REPLY,
35 VARLINK_AWAITING_REPLY_MORE,
36 VARLINK_CALLING,
37 VARLINK_CALLED,
38 VARLINK_PROCESSING_REPLY,
39
40 /* Server side states */
41 VARLINK_IDLE_SERVER,
42 VARLINK_PROCESSING_METHOD,
43 VARLINK_PROCESSING_METHOD_MORE,
44 VARLINK_PROCESSING_METHOD_ONEWAY,
45 VARLINK_PROCESSED_METHOD,
46 VARLINK_PENDING_METHOD,
47 VARLINK_PENDING_METHOD_MORE,
48
49 /* Common states (only during shutdown) */
50 VARLINK_PENDING_DISCONNECT,
51 VARLINK_PENDING_TIMEOUT,
52 VARLINK_PROCESSING_DISCONNECT,
53 VARLINK_PROCESSING_TIMEOUT,
54 VARLINK_PROCESSING_FAILURE,
55 VARLINK_DISCONNECTED,
56
57 _VARLINK_STATE_MAX,
58 _VARLINK_STATE_INVALID = -EINVAL,
59 } VarlinkState;
60
61 /* Tests whether we are not yet disconnected. Note that this is true during all states where the connection
62 * is still good for something, and false only when it's dead for good. This means: when we are
63 * asynchronously connecting to a peer and the connect() is still pending, then this will return 'true', as
64 * the connection is still good, and we are likely to be able to properly operate on it soon. */
65 #define VARLINK_STATE_IS_ALIVE(state) \
66 IN_SET(state, \
67 VARLINK_IDLE_CLIENT, \
68 VARLINK_AWAITING_REPLY, \
69 VARLINK_AWAITING_REPLY_MORE, \
70 VARLINK_CALLING, \
71 VARLINK_CALLED, \
72 VARLINK_PROCESSING_REPLY, \
73 VARLINK_IDLE_SERVER, \
74 VARLINK_PROCESSING_METHOD, \
75 VARLINK_PROCESSING_METHOD_MORE, \
76 VARLINK_PROCESSING_METHOD_ONEWAY, \
77 VARLINK_PROCESSED_METHOD, \
78 VARLINK_PENDING_METHOD, \
79 VARLINK_PENDING_METHOD_MORE)
80
81 struct Varlink {
82 unsigned n_ref;
83
84 VarlinkServer *server;
85
86 VarlinkState state;
87 bool connecting; /* This boolean indicates whether the socket fd we are operating on is currently
88 * processing an asynchronous connect(). In that state we watch the socket for
89 * EPOLLOUT, but we refrain from calling read() or write() on the socket as that
90 * will trigger ENOTCONN. Note that this boolean is kept separate from the
91 * VarlinkState above on purpose: while the connect() is still not complete we
92 * already want to allow queuing of messages and similar. Thus it's nice to keep
93 * these two state concepts separate: the VarlinkState encodes what our own view of
94 * the connection is, i.e. whether we think it's a server, a client, and has
95 * something queued already, while 'connecting' tells us a detail about the
96 * transport used below, that should have no effect on how we otherwise accept and
97 * process operations from the user.
98 *
99 * Or to say this differently: VARLINK_STATE_IS_ALIVE(state) tells you whether the
100 * connection is good to use, even if it might not be fully connected
101 * yet. connecting=true then informs you that actually we are still connecting, and
102 * the connection is actually not established yet and thus any requests you enqueue
103 * now will still work fine but will be queued only, not sent yet, but that
104 * shouldn't stop you from using the connection, since eventually whatever you queue
105 * *will* be sent.
106 *
107 * Or to say this even differently: 'state' is a high-level ("application layer"
108 * high, if you so will) state, while 'conecting' is a low-level ("transport layer"
109 * low, if you so will) state, and while they are not entirely unrelated and
110 * sometimes propagate effects to each other they are only asynchronously connected
111 * at most. */
112 unsigned n_pending;
113
114 int fd;
115
116 char *input_buffer; /* valid data starts at input_buffer_index, ends at input_buffer_index+input_buffer_size */
117 size_t input_buffer_index;
118 size_t input_buffer_size;
119 size_t input_buffer_unscanned;
120
121 char *output_buffer; /* valid data starts at output_buffer_index, ends at output_buffer_index+output_buffer_size */
122 size_t output_buffer_index;
123 size_t output_buffer_size;
124
125 VarlinkReply reply_callback;
126
127 JsonVariant *current;
128 JsonVariant *reply;
129
130 struct ucred ucred;
131 bool ucred_acquired:1;
132
133 bool write_disconnected:1;
134 bool read_disconnected:1;
135 bool prefer_read_write:1;
136 bool got_pollhup:1;
137
138 usec_t timestamp;
139 usec_t timeout;
140
141 void *userdata;
142 char *description;
143
144 sd_event *event;
145 sd_event_source *io_event_source;
146 sd_event_source *time_event_source;
147 sd_event_source *quit_event_source;
148 sd_event_source *defer_event_source;
149 };
150
151 typedef struct VarlinkServerSocket VarlinkServerSocket;
152
153 struct VarlinkServerSocket {
154 VarlinkServer *server;
155
156 int fd;
157 char *address;
158
159 sd_event_source *event_source;
160
161 LIST_FIELDS(VarlinkServerSocket, sockets);
162 };
163
164 struct VarlinkServer {
165 unsigned n_ref;
166 VarlinkServerFlags flags;
167
168 LIST_HEAD(VarlinkServerSocket, sockets);
169
170 Hashmap *methods;
171 VarlinkConnect connect_callback;
172 VarlinkDisconnect disconnect_callback;
173
174 sd_event *event;
175 int64_t event_priority;
176
177 unsigned n_connections;
178 Hashmap *by_uid;
179
180 void *userdata;
181 char *description;
182
183 unsigned connections_max;
184 unsigned connections_per_uid_max;
185 };
186
187 static const char* const varlink_state_table[_VARLINK_STATE_MAX] = {
188 [VARLINK_IDLE_CLIENT] = "idle-client",
189 [VARLINK_AWAITING_REPLY] = "awaiting-reply",
190 [VARLINK_AWAITING_REPLY_MORE] = "awaiting-reply-more",
191 [VARLINK_CALLING] = "calling",
192 [VARLINK_CALLED] = "called",
193 [VARLINK_PROCESSING_REPLY] = "processing-reply",
194 [VARLINK_IDLE_SERVER] = "idle-server",
195 [VARLINK_PROCESSING_METHOD] = "processing-method",
196 [VARLINK_PROCESSING_METHOD_MORE] = "processing-method-more",
197 [VARLINK_PROCESSING_METHOD_ONEWAY] = "processing-method-oneway",
198 [VARLINK_PROCESSED_METHOD] = "processed-method",
199 [VARLINK_PENDING_METHOD] = "pending-method",
200 [VARLINK_PENDING_METHOD_MORE] = "pending-method-more",
201 [VARLINK_PENDING_DISCONNECT] = "pending-disconnect",
202 [VARLINK_PENDING_TIMEOUT] = "pending-timeout",
203 [VARLINK_PROCESSING_DISCONNECT] = "processing-disconnect",
204 [VARLINK_PROCESSING_TIMEOUT] = "processing-timeout",
205 [VARLINK_PROCESSING_FAILURE] = "processing-failure",
206 [VARLINK_DISCONNECTED] = "disconnected",
207 };
208
209 DEFINE_PRIVATE_STRING_TABLE_LOOKUP_TO_STRING(varlink_state, VarlinkState);
210
211 #define varlink_log_errno(v, error, fmt, ...) \
212 log_debug_errno(error, "%s: " fmt, varlink_description(v), ##__VA_ARGS__)
213
214 #define varlink_log(v, fmt, ...) \
215 log_debug("%s: " fmt, varlink_description(v), ##__VA_ARGS__)
216
217 #define varlink_server_log_errno(s, error, fmt, ...) \
218 log_debug_errno(error, "%s: " fmt, varlink_server_description(s), ##__VA_ARGS__)
219
220 #define varlink_server_log(s, fmt, ...) \
221 log_debug("%s: " fmt, varlink_server_description(s), ##__VA_ARGS__)
222
223 static inline const char *varlink_description(Varlink *v) {
224 return (v ? v->description : NULL) ?: "varlink";
225 }
226
227 static inline const char *varlink_server_description(VarlinkServer *s) {
228 return (s ? s->description : NULL) ?: "varlink";
229 }
230
231 static void varlink_set_state(Varlink *v, VarlinkState state) {
232 assert(v);
233 assert(state >= 0 && state < _VARLINK_STATE_MAX);
234
235 if (v->state < 0)
236 varlink_log(v, "Setting state %s",
237 varlink_state_to_string(state));
238 else
239 varlink_log(v, "Changing state %s → %s",
240 varlink_state_to_string(v->state),
241 varlink_state_to_string(state));
242
243 v->state = state;
244 }
245
246 static int varlink_new(Varlink **ret) {
247 Varlink *v;
248
249 assert(ret);
250
251 v = new(Varlink, 1);
252 if (!v)
253 return -ENOMEM;
254
255 *v = (Varlink) {
256 .n_ref = 1,
257 .fd = -1,
258
259 .state = _VARLINK_STATE_INVALID,
260
261 .ucred.uid = UID_INVALID,
262 .ucred.gid = GID_INVALID,
263
264 .timestamp = USEC_INFINITY,
265 .timeout = VARLINK_DEFAULT_TIMEOUT_USEC
266 };
267
268 *ret = v;
269 return 0;
270 }
271
272 int varlink_connect_address(Varlink **ret, const char *address) {
273 _cleanup_(varlink_unrefp) Varlink *v = NULL;
274 union sockaddr_union sockaddr;
275 socklen_t sockaddr_len;
276 int r;
277
278 assert_return(ret, -EINVAL);
279 assert_return(address, -EINVAL);
280
281 r = sockaddr_un_set_path(&sockaddr.un, address);
282 if (r < 0)
283 return log_debug_errno(r, "Failed to set socket address '%s': %m", address);
284 sockaddr_len = r;
285
286 r = varlink_new(&v);
287 if (r < 0)
288 return log_debug_errno(r, "Failed to create varlink object: %m");
289
290 v->fd = socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
291 if (v->fd < 0)
292 return log_debug_errno(errno, "Failed to create AF_UNIX socket: %m");
293
294 v->fd = fd_move_above_stdio(v->fd);
295
296 if (connect(v->fd, &sockaddr.sa, sockaddr_len) < 0) {
297 if (!IN_SET(errno, EAGAIN, EINPROGRESS))
298 return log_debug_errno(errno, "Failed to connect to %s: %m", address);
299
300 v->connecting = true; /* We are asynchronously connecting, i.e. the connect() is being
301 * processed in the background. As long as that's the case the socket
302 * is in a special state: it's there, we can poll it for EPOLLOUT, but
303 * if we attempt to write() to it before we see EPOLLOUT we'll get
304 * ENOTCONN (and not EAGAIN, like we would for a normal connected
305 * socket that isn't writable at the moment). Since ENOTCONN on write()
306 * hence can mean two different things (i.e. connection not complete
307 * yet vs. already disconnected again), we store as a boolean whether
308 * we are still in connect(). */
309 }
310
311 varlink_set_state(v, VARLINK_IDLE_CLIENT);
312
313 *ret = TAKE_PTR(v);
314 return 0;
315 }
316
317 int varlink_connect_fd(Varlink **ret, int fd) {
318 Varlink *v;
319 int r;
320
321 assert_return(ret, -EINVAL);
322 assert_return(fd >= 0, -EBADF);
323
324 r = fd_nonblock(fd, true);
325 if (r < 0)
326 return log_debug_errno(r, "Failed to make fd %d nonblocking: %m", fd);
327
328 r = varlink_new(&v);
329 if (r < 0)
330 return log_debug_errno(r, "Failed to create varlink object: %m");
331
332 v->fd = fd;
333 varlink_set_state(v, VARLINK_IDLE_CLIENT);
334
335 /* Note that if this function is called we assume the passed socket (if it is one) is already
336 * properly connected, i.e. any asynchronous connect() done on it already completed. Because of that
337 * we'll not set the 'connecting' boolean here, i.e. we don't need to avoid write()ing to the socket
338 * until the connection is fully set up. Behaviour here is hence a bit different from
339 * varlink_connect_address() above, as there we do handle asynchronous connections ourselves and
340 * avoid doing write() on it before we saw EPOLLOUT for the first time. */
341
342 *ret = v;
343 return 0;
344 }
345
346 static void varlink_detach_event_sources(Varlink *v) {
347 assert(v);
348
349 v->io_event_source = sd_event_source_disable_unref(v->io_event_source);
350 v->time_event_source = sd_event_source_disable_unref(v->time_event_source);
351 v->quit_event_source = sd_event_source_disable_unref(v->quit_event_source);
352 v->defer_event_source = sd_event_source_disable_unref(v->defer_event_source);
353 }
354
355 static void varlink_clear(Varlink *v) {
356 assert(v);
357
358 varlink_detach_event_sources(v);
359
360 v->fd = safe_close(v->fd);
361
362 v->input_buffer = mfree(v->input_buffer);
363 v->output_buffer = mfree(v->output_buffer);
364
365 v->current = json_variant_unref(v->current);
366 v->reply = json_variant_unref(v->reply);
367
368 v->event = sd_event_unref(v->event);
369 }
370
371 static Varlink* varlink_destroy(Varlink *v) {
372 if (!v)
373 return NULL;
374
375 /* If this is called the server object must already been unreffed here. Why that? because when we
376 * linked up the varlink connection with the server object we took one ref in each direction */
377 assert(!v->server);
378
379 varlink_clear(v);
380
381 free(v->description);
382 return mfree(v);
383 }
384
385 DEFINE_TRIVIAL_REF_UNREF_FUNC(Varlink, varlink, varlink_destroy);
386
387 static int varlink_test_disconnect(Varlink *v) {
388 assert(v);
389
390 /* Tests whether we the connection has been terminated. We are careful to not stop processing it
391 * prematurely, since we want to handle half-open connections as well as possible and want to flush
392 * out and read data before we close down if we can. */
393
394 /* Already disconnected? */
395 if (!VARLINK_STATE_IS_ALIVE(v->state))
396 return 0;
397
398 /* Wait until connection setup is complete, i.e. until asynchronous connect() completes */
399 if (v->connecting)
400 return 0;
401
402 /* Still something to write and we can write? Stay around */
403 if (v->output_buffer_size > 0 && !v->write_disconnected)
404 return 0;
405
406 /* Both sides gone already? Then there's no need to stick around */
407 if (v->read_disconnected && v->write_disconnected)
408 goto disconnect;
409
410 /* If we are waiting for incoming data but the read side is shut down, disconnect. */
411 if (IN_SET(v->state, VARLINK_AWAITING_REPLY, VARLINK_AWAITING_REPLY_MORE, VARLINK_CALLING, VARLINK_IDLE_SERVER) && v->read_disconnected)
412 goto disconnect;
413
414 /* Similar, if are a client that hasn't written anything yet but the write side is dead, also
415 * disconnect. We also explicitly check for POLLHUP here since we likely won't notice the write side
416 * being down if we never wrote anything. */
417 if (IN_SET(v->state, VARLINK_IDLE_CLIENT) && (v->write_disconnected || v->got_pollhup))
418 goto disconnect;
419
420 /* The server is still expecting to write more, but its write end is disconnected and it got a POLLHUP
421 * (i.e. from a disconnected client), so disconnect. */
422 if (IN_SET(v->state, VARLINK_PENDING_METHOD, VARLINK_PENDING_METHOD_MORE) && v->write_disconnected && v->got_pollhup)
423 goto disconnect;
424
425 return 0;
426
427 disconnect:
428 varlink_set_state(v, VARLINK_PENDING_DISCONNECT);
429 return 1;
430 }
431
432 static int varlink_write(Varlink *v) {
433 ssize_t n;
434
435 assert(v);
436
437 if (!VARLINK_STATE_IS_ALIVE(v->state))
438 return 0;
439 if (v->connecting) /* Writing while we are still wait for a non-blocking connect() to complete will
440 * result in ENOTCONN, hence exit early here */
441 return 0;
442 if (v->output_buffer_size == 0)
443 return 0;
444 if (v->write_disconnected)
445 return 0;
446
447 assert(v->fd >= 0);
448
449 /* We generally prefer recv()/send() (mostly because of MSG_NOSIGNAL) but also want to be compatible
450 * with non-socket IO, hence fall back automatically.
451 *
452 * Use a local variable to help gcc figure out that we set 'n' in all cases. */
453 bool prefer_write = v->prefer_read_write;
454 if (!prefer_write) {
455 n = send(v->fd, v->output_buffer + v->output_buffer_index, v->output_buffer_size, MSG_DONTWAIT|MSG_NOSIGNAL);
456 if (n < 0 && errno == ENOTSOCK)
457 prefer_write = v->prefer_read_write = true;
458 }
459 if (prefer_write)
460 n = write(v->fd, v->output_buffer + v->output_buffer_index, v->output_buffer_size);
461 if (n < 0) {
462 if (errno == EAGAIN)
463 return 0;
464
465 if (ERRNO_IS_DISCONNECT(errno)) {
466 /* If we get informed about a disconnect on write, then let's remember that, but not
467 * act on it just yet. Let's wait for read() to report the issue first. */
468 v->write_disconnected = true;
469 return 1;
470 }
471
472 return -errno;
473 }
474
475 v->output_buffer_size -= n;
476
477 if (v->output_buffer_size == 0)
478 v->output_buffer_index = 0;
479 else
480 v->output_buffer_index += n;
481
482 v->timestamp = now(CLOCK_MONOTONIC);
483 return 1;
484 }
485
486 static int varlink_read(Varlink *v) {
487 size_t rs;
488 ssize_t n;
489
490 assert(v);
491
492 if (!IN_SET(v->state, VARLINK_AWAITING_REPLY, VARLINK_AWAITING_REPLY_MORE, VARLINK_CALLING, VARLINK_IDLE_SERVER))
493 return 0;
494 if (v->connecting) /* read() on a socket while we are in connect() will fail with EINVAL, hence exit early here */
495 return 0;
496 if (v->current)
497 return 0;
498 if (v->input_buffer_unscanned > 0)
499 return 0;
500 if (v->read_disconnected)
501 return 0;
502
503 if (v->input_buffer_size >= VARLINK_BUFFER_MAX)
504 return -ENOBUFS;
505
506 assert(v->fd >= 0);
507
508 if (MALLOC_SIZEOF_SAFE(v->input_buffer) <= v->input_buffer_index + v->input_buffer_size) {
509 size_t add;
510
511 add = MIN(VARLINK_BUFFER_MAX - v->input_buffer_size, VARLINK_READ_SIZE);
512
513 if (v->input_buffer_index == 0) {
514
515 if (!GREEDY_REALLOC(v->input_buffer, v->input_buffer_size + add))
516 return -ENOMEM;
517
518 } else {
519 char *b;
520
521 b = new(char, v->input_buffer_size + add);
522 if (!b)
523 return -ENOMEM;
524
525 memcpy(b, v->input_buffer + v->input_buffer_index, v->input_buffer_size);
526
527 free_and_replace(v->input_buffer, b);
528 v->input_buffer_index = 0;
529 }
530 }
531
532 rs = MALLOC_SIZEOF_SAFE(v->input_buffer) - (v->input_buffer_index + v->input_buffer_size);
533
534 bool prefer_read = v->prefer_read_write;
535 if (!prefer_read) {
536 n = recv(v->fd, v->input_buffer + v->input_buffer_index + v->input_buffer_size, rs, MSG_DONTWAIT);
537 if (n < 0 && errno == ENOTSOCK)
538 prefer_read = v->prefer_read_write = true;
539 }
540 if (prefer_read)
541 n = read(v->fd, v->input_buffer + v->input_buffer_index + v->input_buffer_size, rs);
542 if (n < 0) {
543 if (errno == EAGAIN)
544 return 0;
545
546 if (ERRNO_IS_DISCONNECT(errno)) {
547 v->read_disconnected = true;
548 return 1;
549 }
550
551 return -errno;
552 }
553 if (n == 0) { /* EOF */
554 v->read_disconnected = true;
555 return 1;
556 }
557
558 v->input_buffer_size += n;
559 v->input_buffer_unscanned += n;
560
561 return 1;
562 }
563
564 static int varlink_parse_message(Varlink *v) {
565 const char *e, *begin;
566 size_t sz;
567 int r;
568
569 assert(v);
570
571 if (v->current)
572 return 0;
573 if (v->input_buffer_unscanned <= 0)
574 return 0;
575
576 assert(v->input_buffer_unscanned <= v->input_buffer_size);
577 assert(v->input_buffer_index + v->input_buffer_size <= MALLOC_SIZEOF_SAFE(v->input_buffer));
578
579 begin = v->input_buffer + v->input_buffer_index;
580
581 e = memchr(begin + v->input_buffer_size - v->input_buffer_unscanned, 0, v->input_buffer_unscanned);
582 if (!e) {
583 v->input_buffer_unscanned = 0;
584 return 0;
585 }
586
587 sz = e - begin + 1;
588
589 varlink_log(v, "New incoming message: %s", begin); /* FIXME: should we output the whole message here before validation?
590 * This may produce a non-printable journal entry if the message
591 * is invalid. We may also expose privileged information. */
592
593 r = json_parse(begin, 0, &v->current, NULL, NULL);
594 if (r < 0) {
595 /* If we encounter a parse failure flush all data. We cannot possibly recover from this,
596 * hence drop all buffered data now. */
597 v->input_buffer_index = v->input_buffer_size = v->input_buffer_unscanned = 0;
598 return varlink_log_errno(v, r, "Failed to parse JSON: %m");
599 }
600
601 v->input_buffer_size -= sz;
602
603 if (v->input_buffer_size == 0)
604 v->input_buffer_index = 0;
605 else
606 v->input_buffer_index += sz;
607
608 v->input_buffer_unscanned = v->input_buffer_size;
609 return 1;
610 }
611
612 static int varlink_test_timeout(Varlink *v) {
613 assert(v);
614
615 if (!IN_SET(v->state, VARLINK_AWAITING_REPLY, VARLINK_AWAITING_REPLY_MORE, VARLINK_CALLING))
616 return 0;
617 if (v->timeout == USEC_INFINITY)
618 return 0;
619
620 if (now(CLOCK_MONOTONIC) < usec_add(v->timestamp, v->timeout))
621 return 0;
622
623 varlink_set_state(v, VARLINK_PENDING_TIMEOUT);
624
625 return 1;
626 }
627
628 static int varlink_dispatch_local_error(Varlink *v, const char *error) {
629 int r;
630
631 assert(v);
632 assert(error);
633
634 if (!v->reply_callback)
635 return 0;
636
637 r = v->reply_callback(v, NULL, error, VARLINK_REPLY_ERROR|VARLINK_REPLY_LOCAL, v->userdata);
638 if (r < 0)
639 log_debug_errno(r, "Reply callback returned error, ignoring: %m");
640
641 return 1;
642 }
643
644 static int varlink_dispatch_timeout(Varlink *v) {
645 assert(v);
646
647 if (v->state != VARLINK_PENDING_TIMEOUT)
648 return 0;
649
650 varlink_set_state(v, VARLINK_PROCESSING_TIMEOUT);
651 varlink_dispatch_local_error(v, VARLINK_ERROR_TIMEOUT);
652 varlink_close(v);
653
654 return 1;
655 }
656
657 static int varlink_dispatch_disconnect(Varlink *v) {
658 assert(v);
659
660 if (v->state != VARLINK_PENDING_DISCONNECT)
661 return 0;
662
663 varlink_set_state(v, VARLINK_PROCESSING_DISCONNECT);
664 varlink_dispatch_local_error(v, VARLINK_ERROR_DISCONNECTED);
665 varlink_close(v);
666
667 return 1;
668 }
669
670 static int varlink_sanitize_parameters(JsonVariant **v) {
671 assert(v);
672
673 /* Varlink always wants a parameters list, hence make one if the caller doesn't want any */
674 if (!*v)
675 return json_variant_new_object(v, NULL, 0);
676 else if (!json_variant_is_object(*v))
677 return -EINVAL;
678
679 return 0;
680 }
681
682 static int varlink_dispatch_reply(Varlink *v) {
683 _cleanup_(json_variant_unrefp) JsonVariant *parameters = NULL;
684 VarlinkReplyFlags flags = 0;
685 const char *error = NULL;
686 JsonVariant *e;
687 const char *k;
688 int r;
689
690 assert(v);
691
692 if (!IN_SET(v->state, VARLINK_AWAITING_REPLY, VARLINK_AWAITING_REPLY_MORE, VARLINK_CALLING))
693 return 0;
694 if (!v->current)
695 return 0;
696
697 assert(v->n_pending > 0);
698
699 if (!json_variant_is_object(v->current))
700 goto invalid;
701
702 JSON_VARIANT_OBJECT_FOREACH(k, e, v->current) {
703
704 if (streq(k, "error")) {
705 if (error)
706 goto invalid;
707 if (!json_variant_is_string(e))
708 goto invalid;
709
710 error = json_variant_string(e);
711 flags |= VARLINK_REPLY_ERROR;
712
713 } else if (streq(k, "parameters")) {
714 if (parameters)
715 goto invalid;
716 if (!json_variant_is_object(e))
717 goto invalid;
718
719 parameters = json_variant_ref(e);
720
721 } else if (streq(k, "continues")) {
722 if (FLAGS_SET(flags, VARLINK_REPLY_CONTINUES))
723 goto invalid;
724
725 if (!json_variant_is_boolean(e))
726 goto invalid;
727
728 if (json_variant_boolean(e))
729 flags |= VARLINK_REPLY_CONTINUES;
730 } else
731 goto invalid;
732 }
733
734 /* Replies with 'continue' set are only OK if we set 'more' when the method call was initiated */
735 if (v->state != VARLINK_AWAITING_REPLY_MORE && FLAGS_SET(flags, VARLINK_REPLY_CONTINUES))
736 goto invalid;
737
738 /* An error is final */
739 if (error && FLAGS_SET(flags, VARLINK_REPLY_CONTINUES))
740 goto invalid;
741
742 r = varlink_sanitize_parameters(&parameters);
743 if (r < 0)
744 goto invalid;
745
746 if (IN_SET(v->state, VARLINK_AWAITING_REPLY, VARLINK_AWAITING_REPLY_MORE)) {
747 varlink_set_state(v, VARLINK_PROCESSING_REPLY);
748
749 if (v->reply_callback) {
750 r = v->reply_callback(v, parameters, error, flags, v->userdata);
751 if (r < 0)
752 log_debug_errno(r, "Reply callback returned error, ignoring: %m");
753 }
754
755 v->current = json_variant_unref(v->current);
756
757 if (v->state == VARLINK_PROCESSING_REPLY) {
758
759 assert(v->n_pending > 0);
760
761 if (!FLAGS_SET(flags, VARLINK_REPLY_CONTINUES))
762 v->n_pending--;
763
764 varlink_set_state(v,
765 FLAGS_SET(flags, VARLINK_REPLY_CONTINUES) ? VARLINK_AWAITING_REPLY_MORE :
766 v->n_pending == 0 ? VARLINK_IDLE_CLIENT : VARLINK_AWAITING_REPLY);
767 }
768 } else {
769 assert(v->state == VARLINK_CALLING);
770 varlink_set_state(v, VARLINK_CALLED);
771 }
772
773 return 1;
774
775 invalid:
776 varlink_set_state(v, VARLINK_PROCESSING_FAILURE);
777 varlink_dispatch_local_error(v, VARLINK_ERROR_PROTOCOL);
778 varlink_close(v);
779
780 return 1;
781 }
782
783 static int varlink_dispatch_method(Varlink *v) {
784 _cleanup_(json_variant_unrefp) JsonVariant *parameters = NULL;
785 VarlinkMethodFlags flags = 0;
786 const char *method = NULL, *error;
787 JsonVariant *e;
788 VarlinkMethod callback;
789 const char *k;
790 int r;
791
792 assert(v);
793
794 if (v->state != VARLINK_IDLE_SERVER)
795 return 0;
796 if (!v->current)
797 return 0;
798
799 if (!json_variant_is_object(v->current))
800 goto invalid;
801
802 JSON_VARIANT_OBJECT_FOREACH(k, e, v->current) {
803
804 if (streq(k, "method")) {
805 if (method)
806 goto invalid;
807 if (!json_variant_is_string(e))
808 goto invalid;
809
810 method = json_variant_string(e);
811
812 } else if (streq(k, "parameters")) {
813 if (parameters)
814 goto invalid;
815 if (!json_variant_is_object(e))
816 goto invalid;
817
818 parameters = json_variant_ref(e);
819
820 } else if (streq(k, "oneway")) {
821
822 if ((flags & (VARLINK_METHOD_ONEWAY|VARLINK_METHOD_MORE)) != 0)
823 goto invalid;
824
825 if (!json_variant_is_boolean(e))
826 goto invalid;
827
828 if (json_variant_boolean(e))
829 flags |= VARLINK_METHOD_ONEWAY;
830
831 } else if (streq(k, "more")) {
832
833 if ((flags & (VARLINK_METHOD_ONEWAY|VARLINK_METHOD_MORE)) != 0)
834 goto invalid;
835
836 if (!json_variant_is_boolean(e))
837 goto invalid;
838
839 if (json_variant_boolean(e))
840 flags |= VARLINK_METHOD_MORE;
841
842 } else
843 goto invalid;
844 }
845
846 if (!method)
847 goto invalid;
848
849 r = varlink_sanitize_parameters(&parameters);
850 if (r < 0)
851 goto fail;
852
853 varlink_set_state(v, (flags & VARLINK_METHOD_MORE) ? VARLINK_PROCESSING_METHOD_MORE :
854 (flags & VARLINK_METHOD_ONEWAY) ? VARLINK_PROCESSING_METHOD_ONEWAY :
855 VARLINK_PROCESSING_METHOD);
856
857 assert(v->server);
858
859 if (STR_IN_SET(method, "org.varlink.service.GetInfo", "org.varlink.service.GetInterface")) {
860 /* For now, we don't implement a single of varlink's own methods */
861 callback = NULL;
862 error = VARLINK_ERROR_METHOD_NOT_IMPLEMENTED;
863 } else if (startswith(method, "org.varlink.service.")) {
864 callback = NULL;
865 error = VARLINK_ERROR_METHOD_NOT_FOUND;
866 } else {
867 callback = hashmap_get(v->server->methods, method);
868 error = VARLINK_ERROR_METHOD_NOT_FOUND;
869 }
870
871 if (callback) {
872 r = callback(v, parameters, flags, v->userdata);
873 if (r < 0) {
874 log_debug_errno(r, "Callback for %s returned error: %m", method);
875
876 /* We got an error back from the callback. Propagate it to the client if the method call remains unanswered. */
877 if (!FLAGS_SET(flags, VARLINK_METHOD_ONEWAY)) {
878 r = varlink_error_errno(v, r);
879 if (r < 0)
880 return r;
881 }
882 }
883 } else if (!FLAGS_SET(flags, VARLINK_METHOD_ONEWAY)) {
884 assert(error);
885
886 r = varlink_errorb(v, error, JSON_BUILD_OBJECT(JSON_BUILD_PAIR("method", JSON_BUILD_STRING(method))));
887 if (r < 0)
888 return r;
889 }
890
891 switch (v->state) {
892
893 case VARLINK_PROCESSED_METHOD: /* Method call is fully processed */
894 case VARLINK_PROCESSING_METHOD_ONEWAY: /* ditto */
895 v->current = json_variant_unref(v->current);
896 varlink_set_state(v, VARLINK_IDLE_SERVER);
897 break;
898
899 case VARLINK_PROCESSING_METHOD: /* Method call wasn't replied to, will be replied to later */
900 varlink_set_state(v, VARLINK_PENDING_METHOD);
901 break;
902
903 case VARLINK_PROCESSING_METHOD_MORE: /* No reply for a "more" message was sent, more to come */
904 varlink_set_state(v, VARLINK_PENDING_METHOD_MORE);
905 break;
906
907 default:
908 assert_not_reached("Unexpected state");
909
910 }
911
912 return r;
913
914 invalid:
915 r = -EINVAL;
916
917 fail:
918 varlink_set_state(v, VARLINK_PROCESSING_FAILURE);
919 varlink_dispatch_local_error(v, VARLINK_ERROR_PROTOCOL);
920 varlink_close(v);
921
922 return r;
923 }
924
925 int varlink_process(Varlink *v) {
926 int r;
927
928 assert_return(v, -EINVAL);
929
930 if (v->state == VARLINK_DISCONNECTED)
931 return varlink_log_errno(v, SYNTHETIC_ERRNO(ENOTCONN), "Not connected.");
932
933 varlink_ref(v);
934
935 r = varlink_write(v);
936 if (r < 0)
937 varlink_log_errno(v, r, "Write failed: %m");
938 if (r != 0)
939 goto finish;
940
941 r = varlink_dispatch_reply(v);
942 if (r < 0)
943 varlink_log_errno(v, r, "Reply dispatch failed: %m");
944 if (r != 0)
945 goto finish;
946
947 r = varlink_dispatch_method(v);
948 if (r < 0)
949 varlink_log_errno(v, r, "Method dispatch failed: %m");
950 if (r != 0)
951 goto finish;
952
953 r = varlink_parse_message(v);
954 if (r < 0)
955 varlink_log_errno(v, r, "Message parsing failed: %m");
956 if (r != 0)
957 goto finish;
958
959 r = varlink_read(v);
960 if (r < 0)
961 varlink_log_errno(v, r, "Read failed: %m");
962 if (r != 0)
963 goto finish;
964
965 r = varlink_test_disconnect(v);
966 assert(r >= 0);
967 if (r != 0)
968 goto finish;
969
970 r = varlink_dispatch_disconnect(v);
971 assert(r >= 0);
972 if (r != 0)
973 goto finish;
974
975 r = varlink_test_timeout(v);
976 assert(r >= 0);
977 if (r != 0)
978 goto finish;
979
980 r = varlink_dispatch_timeout(v);
981 assert(r >= 0);
982 if (r != 0)
983 goto finish;
984
985 finish:
986 if (r >= 0 && v->defer_event_source) {
987 int q;
988
989 /* If we did some processing, make sure we are called again soon */
990 q = sd_event_source_set_enabled(v->defer_event_source, r > 0 ? SD_EVENT_ON : SD_EVENT_OFF);
991 if (q < 0)
992 r = varlink_log_errno(v, q, "Failed to enable deferred event source: %m");
993 }
994
995 if (r < 0) {
996 if (VARLINK_STATE_IS_ALIVE(v->state))
997 /* Initiate disconnection */
998 varlink_set_state(v, VARLINK_PENDING_DISCONNECT);
999 else
1000 /* We failed while disconnecting, in that case close right away */
1001 varlink_close(v);
1002 }
1003
1004 varlink_unref(v);
1005 return r;
1006 }
1007
1008 static void handle_revents(Varlink *v, int revents) {
1009 assert(v);
1010
1011 if (v->connecting) {
1012 /* If we have seen POLLOUT or POLLHUP on a socket we are asynchronously waiting a connect()
1013 * to complete on, we know we are ready. We don't read the connection error here though,
1014 * we'll get the error on the next read() or write(). */
1015 if ((revents & (POLLOUT|POLLHUP)) == 0)
1016 return;
1017
1018 varlink_log(v, "Anynchronous connection completed.");
1019 v->connecting = false;
1020 } else {
1021 /* Note that we don't care much about POLLIN/POLLOUT here, we'll just try reading and writing
1022 * what we can. However, we do care about POLLHUP to detect connection termination even if we
1023 * momentarily don't want to read nor write anything. */
1024
1025 if (!FLAGS_SET(revents, POLLHUP))
1026 return;
1027
1028 varlink_log(v, "Got POLLHUP from socket.");
1029 v->got_pollhup = true;
1030 }
1031 }
1032
1033 int varlink_wait(Varlink *v, usec_t timeout) {
1034 int r, fd, events;
1035 usec_t t;
1036
1037 assert_return(v, -EINVAL);
1038
1039 if (v->state == VARLINK_DISCONNECTED)
1040 return varlink_log_errno(v, SYNTHETIC_ERRNO(ENOTCONN), "Not connected.");
1041
1042 r = varlink_get_timeout(v, &t);
1043 if (r < 0)
1044 return r;
1045 if (t != USEC_INFINITY) {
1046 usec_t n;
1047
1048 n = now(CLOCK_MONOTONIC);
1049 if (t < n)
1050 t = 0;
1051 else
1052 t = usec_sub_unsigned(t, n);
1053 }
1054
1055 if (timeout != USEC_INFINITY &&
1056 (t == USEC_INFINITY || timeout < t))
1057 t = timeout;
1058
1059 fd = varlink_get_fd(v);
1060 if (fd < 0)
1061 return fd;
1062
1063 events = varlink_get_events(v);
1064 if (events < 0)
1065 return events;
1066
1067 r = fd_wait_for_event(fd, events, t);
1068 if (r <= 0)
1069 return r;
1070
1071 handle_revents(v, r);
1072 return 1;
1073 }
1074
1075 int varlink_get_fd(Varlink *v) {
1076
1077 assert_return(v, -EINVAL);
1078
1079 if (v->state == VARLINK_DISCONNECTED)
1080 return varlink_log_errno(v, SYNTHETIC_ERRNO(ENOTCONN), "Not connected.");
1081 if (v->fd < 0)
1082 return varlink_log_errno(v, SYNTHETIC_ERRNO(EBADF), "No valid fd.");
1083
1084 return v->fd;
1085 }
1086
1087 int varlink_get_events(Varlink *v) {
1088 int ret = 0;
1089
1090 assert_return(v, -EINVAL);
1091
1092 if (v->state == VARLINK_DISCONNECTED)
1093 return varlink_log_errno(v, SYNTHETIC_ERRNO(ENOTCONN), "Not connected.");
1094
1095 if (v->connecting) /* When processing an asynchronous connect(), we only wait for EPOLLOUT, which
1096 * tells us that the connection is now complete. Before that we should neither
1097 * write() or read() from the fd. */
1098 return EPOLLOUT;
1099
1100 if (!v->read_disconnected &&
1101 IN_SET(v->state, VARLINK_AWAITING_REPLY, VARLINK_AWAITING_REPLY_MORE, VARLINK_CALLING, VARLINK_IDLE_SERVER) &&
1102 !v->current &&
1103 v->input_buffer_unscanned <= 0)
1104 ret |= EPOLLIN;
1105
1106 if (!v->write_disconnected &&
1107 v->output_buffer_size > 0)
1108 ret |= EPOLLOUT;
1109
1110 return ret;
1111 }
1112
1113 int varlink_get_timeout(Varlink *v, usec_t *ret) {
1114 assert_return(v, -EINVAL);
1115
1116 if (v->state == VARLINK_DISCONNECTED)
1117 return varlink_log_errno(v, SYNTHETIC_ERRNO(ENOTCONN), "Not connected.");
1118
1119 if (IN_SET(v->state, VARLINK_AWAITING_REPLY, VARLINK_AWAITING_REPLY_MORE, VARLINK_CALLING) &&
1120 v->timeout != USEC_INFINITY) {
1121 if (ret)
1122 *ret = usec_add(v->timestamp, v->timeout);
1123 return 1;
1124 } else {
1125 if (ret)
1126 *ret = USEC_INFINITY;
1127 return 0;
1128 }
1129 }
1130
1131 int varlink_flush(Varlink *v) {
1132 int ret = 0, r;
1133
1134 assert_return(v, -EINVAL);
1135
1136 if (v->state == VARLINK_DISCONNECTED)
1137 return varlink_log_errno(v, SYNTHETIC_ERRNO(ENOTCONN), "Not connected.");
1138
1139 for (;;) {
1140 if (v->output_buffer_size == 0)
1141 break;
1142 if (v->write_disconnected)
1143 return -ECONNRESET;
1144
1145 r = varlink_write(v);
1146 if (r < 0)
1147 return r;
1148 if (r > 0) {
1149 ret = 1;
1150 continue;
1151 }
1152
1153 r = fd_wait_for_event(v->fd, POLLOUT, USEC_INFINITY);
1154 if (r < 0)
1155 return varlink_log_errno(v, r, "Poll failed on fd: %m");
1156
1157 assert(r != 0);
1158
1159 handle_revents(v, r);
1160 }
1161
1162 return ret;
1163 }
1164
1165 static void varlink_detach_server(Varlink *v) {
1166 VarlinkServer *saved_server;
1167 assert(v);
1168
1169 if (!v->server)
1170 return;
1171
1172 if (v->server->by_uid &&
1173 v->ucred_acquired &&
1174 uid_is_valid(v->ucred.uid)) {
1175 unsigned c;
1176
1177 c = PTR_TO_UINT(hashmap_get(v->server->by_uid, UID_TO_PTR(v->ucred.uid)));
1178 assert(c > 0);
1179
1180 if (c == 1)
1181 (void) hashmap_remove(v->server->by_uid, UID_TO_PTR(v->ucred.uid));
1182 else
1183 (void) hashmap_replace(v->server->by_uid, UID_TO_PTR(v->ucred.uid), UINT_TO_PTR(c - 1));
1184 }
1185
1186 assert(v->server->n_connections > 0);
1187 v->server->n_connections--;
1188
1189 /* If this is a connection associated to a server, then let's disconnect the server and the
1190 * connection from each other. This drops the dangling reference that connect_callback() set up. But
1191 * before we release the references, let's call the disconnection callback if it is defined. */
1192
1193 saved_server = TAKE_PTR(v->server);
1194
1195 if (saved_server->disconnect_callback)
1196 saved_server->disconnect_callback(saved_server, v, saved_server->userdata);
1197
1198 varlink_server_unref(saved_server);
1199 varlink_unref(v);
1200 }
1201
1202 int varlink_close(Varlink *v) {
1203 assert_return(v, -EINVAL);
1204
1205 if (v->state == VARLINK_DISCONNECTED)
1206 return 0;
1207
1208 varlink_set_state(v, VARLINK_DISCONNECTED);
1209
1210 /* Let's take a reference first, since varlink_detach_server() might drop the final (dangling) ref
1211 * which would destroy us before we can call varlink_clear() */
1212 varlink_ref(v);
1213 varlink_detach_server(v);
1214 varlink_clear(v);
1215 varlink_unref(v);
1216
1217 return 1;
1218 }
1219
1220 Varlink* varlink_close_unref(Varlink *v) {
1221 if (!v)
1222 return NULL;
1223
1224 (void) varlink_close(v);
1225 return varlink_unref(v);
1226 }
1227
1228 Varlink* varlink_flush_close_unref(Varlink *v) {
1229 if (!v)
1230 return NULL;
1231
1232 (void) varlink_flush(v);
1233 return varlink_close_unref(v);
1234 }
1235
1236 static int varlink_enqueue_json(Varlink *v, JsonVariant *m) {
1237 _cleanup_free_ char *text = NULL;
1238 int r;
1239
1240 assert(v);
1241 assert(m);
1242
1243 r = json_variant_format(m, 0, &text);
1244 if (r < 0)
1245 return r;
1246 assert(text[r] == '\0');
1247
1248 if (v->output_buffer_size + r + 1 > VARLINK_BUFFER_MAX)
1249 return -ENOBUFS;
1250
1251 varlink_log(v, "Sending message: %s", text);
1252
1253 if (v->output_buffer_size == 0) {
1254
1255 free_and_replace(v->output_buffer, text);
1256
1257 v->output_buffer_size = r + 1;
1258 v->output_buffer_index = 0;
1259
1260 } else if (v->output_buffer_index == 0) {
1261
1262 if (!GREEDY_REALLOC(v->output_buffer, v->output_buffer_size + r + 1))
1263 return -ENOMEM;
1264
1265 memcpy(v->output_buffer + v->output_buffer_size, text, r + 1);
1266 v->output_buffer_size += r + 1;
1267
1268 } else {
1269 char *n;
1270 const size_t new_size = v->output_buffer_size + r + 1;
1271
1272 n = new(char, new_size);
1273 if (!n)
1274 return -ENOMEM;
1275
1276 memcpy(mempcpy(n, v->output_buffer + v->output_buffer_index, v->output_buffer_size), text, r + 1);
1277
1278 free_and_replace(v->output_buffer, n);
1279 v->output_buffer_size = new_size;
1280 v->output_buffer_index = 0;
1281 }
1282
1283 return 0;
1284 }
1285
1286 int varlink_send(Varlink *v, const char *method, JsonVariant *parameters) {
1287 _cleanup_(json_variant_unrefp) JsonVariant *m = NULL;
1288 int r;
1289
1290 assert_return(v, -EINVAL);
1291 assert_return(method, -EINVAL);
1292
1293 if (v->state == VARLINK_DISCONNECTED)
1294 return varlink_log_errno(v, SYNTHETIC_ERRNO(ENOTCONN), "Not connected.");
1295
1296 /* We allow enqueuing multiple method calls at once! */
1297 if (!IN_SET(v->state, VARLINK_IDLE_CLIENT, VARLINK_AWAITING_REPLY))
1298 return varlink_log_errno(v, SYNTHETIC_ERRNO(EBUSY), "Connection busy.");
1299
1300 r = varlink_sanitize_parameters(&parameters);
1301 if (r < 0)
1302 return varlink_log_errno(v, r, "Failed to sanitize parameters: %m");
1303
1304 r = json_build(&m, JSON_BUILD_OBJECT(
1305 JSON_BUILD_PAIR("method", JSON_BUILD_STRING(method)),
1306 JSON_BUILD_PAIR("parameters", JSON_BUILD_VARIANT(parameters)),
1307 JSON_BUILD_PAIR("oneway", JSON_BUILD_BOOLEAN(true))));
1308 if (r < 0)
1309 return varlink_log_errno(v, r, "Failed to build json message: %m");
1310
1311 r = varlink_enqueue_json(v, m);
1312 if (r < 0)
1313 return varlink_log_errno(v, r, "Failed to enqueue json message: %m");
1314
1315 /* No state change here, this is one-way only after all */
1316 v->timestamp = now(CLOCK_MONOTONIC);
1317 return 0;
1318 }
1319
1320 int varlink_sendb(Varlink *v, const char *method, ...) {
1321 _cleanup_(json_variant_unrefp) JsonVariant *parameters = NULL;
1322 va_list ap;
1323 int r;
1324
1325 assert_return(v, -EINVAL);
1326
1327 va_start(ap, method);
1328 r = json_buildv(&parameters, ap);
1329 va_end(ap);
1330
1331 if (r < 0)
1332 return varlink_log_errno(v, r, "Failed to build json message: %m");
1333
1334 return varlink_send(v, method, parameters);
1335 }
1336
1337 int varlink_invoke(Varlink *v, const char *method, JsonVariant *parameters) {
1338 _cleanup_(json_variant_unrefp) JsonVariant *m = NULL;
1339 int r;
1340
1341 assert_return(v, -EINVAL);
1342 assert_return(method, -EINVAL);
1343
1344 if (v->state == VARLINK_DISCONNECTED)
1345 return varlink_log_errno(v, SYNTHETIC_ERRNO(ENOTCONN), "Not connected.");
1346
1347 /* We allow enqueuing multiple method calls at once! */
1348 if (!IN_SET(v->state, VARLINK_IDLE_CLIENT, VARLINK_AWAITING_REPLY))
1349 return varlink_log_errno(v, SYNTHETIC_ERRNO(EBUSY), "Connection busy.");
1350
1351 r = varlink_sanitize_parameters(&parameters);
1352 if (r < 0)
1353 return varlink_log_errno(v, r, "Failed to sanitize parameters: %m");
1354
1355 r = json_build(&m, JSON_BUILD_OBJECT(
1356 JSON_BUILD_PAIR("method", JSON_BUILD_STRING(method)),
1357 JSON_BUILD_PAIR("parameters", JSON_BUILD_VARIANT(parameters))));
1358 if (r < 0)
1359 return varlink_log_errno(v, r, "Failed to build json message: %m");
1360
1361 r = varlink_enqueue_json(v, m);
1362 if (r < 0)
1363 return varlink_log_errno(v, r, "Failed to enqueue json message: %m");
1364
1365 varlink_set_state(v, VARLINK_AWAITING_REPLY);
1366 v->n_pending++;
1367 v->timestamp = now(CLOCK_MONOTONIC);
1368
1369 return 0;
1370 }
1371
1372 int varlink_invokeb(Varlink *v, const char *method, ...) {
1373 _cleanup_(json_variant_unrefp) JsonVariant *parameters = NULL;
1374 va_list ap;
1375 int r;
1376
1377 assert_return(v, -EINVAL);
1378
1379 va_start(ap, method);
1380 r = json_buildv(&parameters, ap);
1381 va_end(ap);
1382
1383 if (r < 0)
1384 return varlink_log_errno(v, r, "Failed to build json message: %m");
1385
1386 return varlink_invoke(v, method, parameters);
1387 }
1388
1389 int varlink_observe(Varlink *v, const char *method, JsonVariant *parameters) {
1390 _cleanup_(json_variant_unrefp) JsonVariant *m = NULL;
1391 int r;
1392
1393 assert_return(v, -EINVAL);
1394 assert_return(method, -EINVAL);
1395
1396 if (v->state == VARLINK_DISCONNECTED)
1397 return varlink_log_errno(v, SYNTHETIC_ERRNO(ENOTCONN), "Not connected.");
1398
1399 /* Note that we don't allow enqueuing multiple method calls when we are in more/continues mode! We
1400 * thus insist on an idle client here. */
1401 if (v->state != VARLINK_IDLE_CLIENT)
1402 return varlink_log_errno(v, SYNTHETIC_ERRNO(EBUSY), "Connection busy.");
1403
1404 r = varlink_sanitize_parameters(&parameters);
1405 if (r < 0)
1406 return varlink_log_errno(v, r, "Failed to sanitize parameters: %m");
1407
1408 r = json_build(&m, JSON_BUILD_OBJECT(
1409 JSON_BUILD_PAIR("method", JSON_BUILD_STRING(method)),
1410 JSON_BUILD_PAIR("parameters", JSON_BUILD_VARIANT(parameters)),
1411 JSON_BUILD_PAIR("more", JSON_BUILD_BOOLEAN(true))));
1412 if (r < 0)
1413 return varlink_log_errno(v, r, "Failed to build json message: %m");
1414
1415 r = varlink_enqueue_json(v, m);
1416 if (r < 0)
1417 return varlink_log_errno(v, r, "Failed to enqueue json message: %m");
1418
1419 varlink_set_state(v, VARLINK_AWAITING_REPLY_MORE);
1420 v->n_pending++;
1421 v->timestamp = now(CLOCK_MONOTONIC);
1422
1423 return 0;
1424 }
1425
1426 int varlink_observeb(Varlink *v, const char *method, ...) {
1427 _cleanup_(json_variant_unrefp) JsonVariant *parameters = NULL;
1428 va_list ap;
1429 int r;
1430
1431 assert_return(v, -EINVAL);
1432
1433 va_start(ap, method);
1434 r = json_buildv(&parameters, ap);
1435 va_end(ap);
1436
1437 if (r < 0)
1438 return varlink_log_errno(v, r, "Failed to build json message: %m");
1439
1440 return varlink_observe(v, method, parameters);
1441 }
1442
1443 int varlink_call(
1444 Varlink *v,
1445 const char *method,
1446 JsonVariant *parameters,
1447 JsonVariant **ret_parameters,
1448 const char **ret_error_id,
1449 VarlinkReplyFlags *ret_flags) {
1450
1451 _cleanup_(json_variant_unrefp) JsonVariant *m = NULL;
1452 int r;
1453
1454 assert_return(v, -EINVAL);
1455 assert_return(method, -EINVAL);
1456
1457 if (v->state == VARLINK_DISCONNECTED)
1458 return varlink_log_errno(v, SYNTHETIC_ERRNO(ENOTCONN), "Not connected.");
1459 if (!IN_SET(v->state, VARLINK_IDLE_CLIENT))
1460 return varlink_log_errno(v, SYNTHETIC_ERRNO(EBUSY), "Connection busy.");
1461
1462 assert(v->n_pending == 0); /* n_pending can't be > 0 if we are in VARLINK_IDLE_CLIENT state */
1463
1464 r = varlink_sanitize_parameters(&parameters);
1465 if (r < 0)
1466 return varlink_log_errno(v, r, "Failed to sanitize parameters: %m");
1467
1468 r = json_build(&m, JSON_BUILD_OBJECT(
1469 JSON_BUILD_PAIR("method", JSON_BUILD_STRING(method)),
1470 JSON_BUILD_PAIR("parameters", JSON_BUILD_VARIANT(parameters))));
1471 if (r < 0)
1472 return varlink_log_errno(v, r, "Failed to build json message: %m");
1473
1474 r = varlink_enqueue_json(v, m);
1475 if (r < 0)
1476 return varlink_log_errno(v, r, "Failed to enqueue json message: %m");
1477
1478 varlink_set_state(v, VARLINK_CALLING);
1479 v->n_pending++;
1480 v->timestamp = now(CLOCK_MONOTONIC);
1481
1482 while (v->state == VARLINK_CALLING) {
1483
1484 r = varlink_process(v);
1485 if (r < 0)
1486 return r;
1487 if (r > 0)
1488 continue;
1489
1490 r = varlink_wait(v, USEC_INFINITY);
1491 if (r < 0)
1492 return r;
1493 }
1494
1495 switch (v->state) {
1496
1497 case VARLINK_CALLED:
1498 assert(v->current);
1499
1500 json_variant_unref(v->reply);
1501 v->reply = TAKE_PTR(v->current);
1502
1503 varlink_set_state(v, VARLINK_IDLE_CLIENT);
1504 assert(v->n_pending == 1);
1505 v->n_pending--;
1506
1507 if (ret_parameters)
1508 *ret_parameters = json_variant_by_key(v->reply, "parameters");
1509 if (ret_error_id)
1510 *ret_error_id = json_variant_string(json_variant_by_key(v->reply, "error"));
1511 if (ret_flags)
1512 *ret_flags = 0;
1513
1514 return 1;
1515
1516 case VARLINK_PENDING_DISCONNECT:
1517 case VARLINK_DISCONNECTED:
1518 return varlink_log_errno(v, SYNTHETIC_ERRNO(ECONNRESET), "Connection was closed.");
1519
1520 case VARLINK_PENDING_TIMEOUT:
1521 return varlink_log_errno(v, SYNTHETIC_ERRNO(ETIME), "Connection timed out.");
1522
1523 default:
1524 assert_not_reached("Unexpected state after method call.");
1525 }
1526 }
1527
1528 int varlink_callb(
1529 Varlink *v,
1530 const char *method,
1531 JsonVariant **ret_parameters,
1532 const char **ret_error_id,
1533 VarlinkReplyFlags *ret_flags, ...) {
1534
1535 _cleanup_(json_variant_unrefp) JsonVariant *parameters = NULL;
1536 va_list ap;
1537 int r;
1538
1539 assert_return(v, -EINVAL);
1540
1541 va_start(ap, ret_flags);
1542 r = json_buildv(&parameters, ap);
1543 va_end(ap);
1544
1545 if (r < 0)
1546 return varlink_log_errno(v, r, "Failed to build json message: %m");
1547
1548 return varlink_call(v, method, parameters, ret_parameters, ret_error_id, ret_flags);
1549 }
1550
1551 int varlink_reply(Varlink *v, JsonVariant *parameters) {
1552 _cleanup_(json_variant_unrefp) JsonVariant *m = NULL;
1553 int r;
1554
1555 assert_return(v, -EINVAL);
1556
1557 if (v->state == VARLINK_DISCONNECTED)
1558 return -ENOTCONN;
1559 if (!IN_SET(v->state,
1560 VARLINK_PROCESSING_METHOD, VARLINK_PROCESSING_METHOD_MORE,
1561 VARLINK_PENDING_METHOD, VARLINK_PENDING_METHOD_MORE))
1562 return -EBUSY;
1563
1564 r = varlink_sanitize_parameters(&parameters);
1565 if (r < 0)
1566 return varlink_log_errno(v, r, "Failed to sanitize parameters: %m");
1567
1568 r = json_build(&m, JSON_BUILD_OBJECT(JSON_BUILD_PAIR("parameters", JSON_BUILD_VARIANT(parameters))));
1569 if (r < 0)
1570 return varlink_log_errno(v, r, "Failed to build json message: %m");
1571
1572 r = varlink_enqueue_json(v, m);
1573 if (r < 0)
1574 return varlink_log_errno(v, r, "Failed to enqueue json message: %m");
1575
1576 if (IN_SET(v->state, VARLINK_PENDING_METHOD, VARLINK_PENDING_METHOD_MORE)) {
1577 /* We just replied to a method call that was let hanging for a while (i.e. we were outside of
1578 * the varlink_dispatch_method() stack frame), which means with this reply we are ready to
1579 * process further messages. */
1580 v->current = json_variant_unref(v->current);
1581 varlink_set_state(v, VARLINK_IDLE_SERVER);
1582 } else
1583 /* We replied to a method call from within the varlink_dispatch_method() stack frame), which
1584 * means we should it handle the rest of the state engine. */
1585 varlink_set_state(v, VARLINK_PROCESSED_METHOD);
1586
1587 return 1;
1588 }
1589
1590 int varlink_replyb(Varlink *v, ...) {
1591 _cleanup_(json_variant_unrefp) JsonVariant *parameters = NULL;
1592 va_list ap;
1593 int r;
1594
1595 assert_return(v, -EINVAL);
1596
1597 va_start(ap, v);
1598 r = json_buildv(&parameters, ap);
1599 va_end(ap);
1600
1601 if (r < 0)
1602 return r;
1603
1604 return varlink_reply(v, parameters);
1605 }
1606
1607 int varlink_error(Varlink *v, const char *error_id, JsonVariant *parameters) {
1608 _cleanup_(json_variant_unrefp) JsonVariant *m = NULL;
1609 int r;
1610
1611 assert_return(v, -EINVAL);
1612 assert_return(error_id, -EINVAL);
1613
1614 if (v->state == VARLINK_DISCONNECTED)
1615 return varlink_log_errno(v, SYNTHETIC_ERRNO(ENOTCONN), "Not connected.");
1616 if (!IN_SET(v->state,
1617 VARLINK_PROCESSING_METHOD, VARLINK_PROCESSING_METHOD_MORE,
1618 VARLINK_PENDING_METHOD, VARLINK_PENDING_METHOD_MORE))
1619 return varlink_log_errno(v, SYNTHETIC_ERRNO(EBUSY), "Connection busy.");
1620
1621 r = varlink_sanitize_parameters(&parameters);
1622 if (r < 0)
1623 return varlink_log_errno(v, r, "Failed to sanitize parameters: %m");
1624
1625 r = json_build(&m, JSON_BUILD_OBJECT(
1626 JSON_BUILD_PAIR("error", JSON_BUILD_STRING(error_id)),
1627 JSON_BUILD_PAIR("parameters", JSON_BUILD_VARIANT(parameters))));
1628 if (r < 0)
1629 return varlink_log_errno(v, r, "Failed to build json message: %m");
1630
1631 r = varlink_enqueue_json(v, m);
1632 if (r < 0)
1633 return varlink_log_errno(v, r, "Failed to enqueue json message: %m");
1634
1635 if (IN_SET(v->state, VARLINK_PENDING_METHOD, VARLINK_PENDING_METHOD_MORE)) {
1636 v->current = json_variant_unref(v->current);
1637 varlink_set_state(v, VARLINK_IDLE_SERVER);
1638 } else
1639 varlink_set_state(v, VARLINK_PROCESSED_METHOD);
1640
1641 return 1;
1642 }
1643
1644 int varlink_errorb(Varlink *v, const char *error_id, ...) {
1645 _cleanup_(json_variant_unrefp) JsonVariant *parameters = NULL;
1646 va_list ap;
1647 int r;
1648
1649 assert_return(v, -EINVAL);
1650 assert_return(error_id, -EINVAL);
1651
1652 va_start(ap, error_id);
1653 r = json_buildv(&parameters, ap);
1654 va_end(ap);
1655
1656 if (r < 0)
1657 return varlink_log_errno(v, r, "Failed to build json message: %m");
1658
1659 return varlink_error(v, error_id, parameters);
1660 }
1661
1662 int varlink_error_invalid_parameter(Varlink *v, JsonVariant *parameters) {
1663
1664 assert_return(v, -EINVAL);
1665 assert_return(parameters, -EINVAL);
1666
1667 /* We expect to be called in one of two ways: the 'parameters' argument is a string variant in which
1668 * case it is the parameter key name that is invalid. Or the 'parameters' argument is an object
1669 * variant in which case we'll pull out the first key. The latter mode is useful in functions that
1670 * don't expect any arguments. */
1671
1672 if (json_variant_is_string(parameters))
1673 return varlink_error(v, VARLINK_ERROR_INVALID_PARAMETER, parameters);
1674
1675 if (json_variant_is_object(parameters) &&
1676 json_variant_elements(parameters) > 0)
1677 return varlink_error(v, VARLINK_ERROR_INVALID_PARAMETER,
1678 json_variant_by_index(parameters, 0));
1679
1680 return -EINVAL;
1681 }
1682
1683 int varlink_error_errno(Varlink *v, int error) {
1684 return varlink_errorb(
1685 v,
1686 VARLINK_ERROR_SYSTEM,
1687 JSON_BUILD_OBJECT(JSON_BUILD_PAIR("errno", JSON_BUILD_INTEGER(abs(error)))));
1688 }
1689
1690 int varlink_notify(Varlink *v, JsonVariant *parameters) {
1691 _cleanup_(json_variant_unrefp) JsonVariant *m = NULL;
1692 int r;
1693
1694 assert_return(v, -EINVAL);
1695
1696 if (v->state == VARLINK_DISCONNECTED)
1697 return varlink_log_errno(v, SYNTHETIC_ERRNO(ENOTCONN), "Not connected.");
1698 if (!IN_SET(v->state, VARLINK_PROCESSING_METHOD_MORE, VARLINK_PENDING_METHOD_MORE))
1699 return varlink_log_errno(v, SYNTHETIC_ERRNO(EBUSY), "Connection busy.");
1700
1701 r = varlink_sanitize_parameters(&parameters);
1702 if (r < 0)
1703 return varlink_log_errno(v, r, "Failed to sanitize parameters: %m");
1704
1705 r = json_build(&m, JSON_BUILD_OBJECT(
1706 JSON_BUILD_PAIR("parameters", JSON_BUILD_VARIANT(parameters)),
1707 JSON_BUILD_PAIR("continues", JSON_BUILD_BOOLEAN(true))));
1708 if (r < 0)
1709 return varlink_log_errno(v, r, "Failed to build json message: %m");
1710
1711 r = varlink_enqueue_json(v, m);
1712 if (r < 0)
1713 return varlink_log_errno(v, r, "Failed to enqueue json message: %m");
1714
1715 /* No state change, as more is coming */
1716 return 1;
1717 }
1718
1719 int varlink_notifyb(Varlink *v, ...) {
1720 _cleanup_(json_variant_unrefp) JsonVariant *parameters = NULL;
1721 va_list ap;
1722 int r;
1723
1724 assert_return(v, -EINVAL);
1725
1726 va_start(ap, v);
1727 r = json_buildv(&parameters, ap);
1728 va_end(ap);
1729
1730 if (r < 0)
1731 return varlink_log_errno(v, r, "Failed to build json message: %m");
1732
1733 return varlink_notify(v, parameters);
1734 }
1735
1736 int varlink_bind_reply(Varlink *v, VarlinkReply callback) {
1737 assert_return(v, -EINVAL);
1738
1739 if (callback && v->reply_callback && callback != v->reply_callback)
1740 return varlink_log_errno(v, SYNTHETIC_ERRNO(EBUSY), "A different callback was already set.");
1741
1742 v->reply_callback = callback;
1743
1744 return 0;
1745 }
1746
1747 void* varlink_set_userdata(Varlink *v, void *userdata) {
1748 void *old;
1749
1750 assert_return(v, NULL);
1751
1752 old = v->userdata;
1753 v->userdata = userdata;
1754
1755 return old;
1756 }
1757
1758 void* varlink_get_userdata(Varlink *v) {
1759 assert_return(v, NULL);
1760
1761 return v->userdata;
1762 }
1763
1764 static int varlink_acquire_ucred(Varlink *v) {
1765 int r;
1766
1767 assert(v);
1768
1769 if (v->ucred_acquired)
1770 return 0;
1771
1772 r = getpeercred(v->fd, &v->ucred);
1773 if (r < 0)
1774 return r;
1775
1776 v->ucred_acquired = true;
1777 return 0;
1778 }
1779
1780 int varlink_get_peer_uid(Varlink *v, uid_t *ret) {
1781 int r;
1782
1783 assert_return(v, -EINVAL);
1784 assert_return(ret, -EINVAL);
1785
1786 r = varlink_acquire_ucred(v);
1787 if (r < 0)
1788 return varlink_log_errno(v, r, "Failed to acquire credentials: %m");
1789
1790 if (!uid_is_valid(v->ucred.uid))
1791 return varlink_log_errno(v, SYNTHETIC_ERRNO(ENODATA), "Peer uid is invalid.");
1792
1793 *ret = v->ucred.uid;
1794 return 0;
1795 }
1796
1797 int varlink_get_peer_pid(Varlink *v, pid_t *ret) {
1798 int r;
1799
1800 assert_return(v, -EINVAL);
1801 assert_return(ret, -EINVAL);
1802
1803 r = varlink_acquire_ucred(v);
1804 if (r < 0)
1805 return varlink_log_errno(v, r, "Failed to acquire credentials: %m");
1806
1807 if (!pid_is_valid(v->ucred.pid))
1808 return varlink_log_errno(v, SYNTHETIC_ERRNO(ENODATA), "Peer uid is invalid.");
1809
1810 *ret = v->ucred.pid;
1811 return 0;
1812 }
1813
1814 int varlink_set_relative_timeout(Varlink *v, usec_t timeout) {
1815 assert_return(v, -EINVAL);
1816 assert_return(timeout > 0, -EINVAL);
1817
1818 v->timeout = timeout;
1819 return 0;
1820 }
1821
1822 VarlinkServer *varlink_get_server(Varlink *v) {
1823 assert_return(v, NULL);
1824
1825 return v->server;
1826 }
1827
1828 int varlink_set_description(Varlink *v, const char *description) {
1829 assert_return(v, -EINVAL);
1830
1831 return free_and_strdup(&v->description, description);
1832 }
1833
1834 static int io_callback(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
1835 Varlink *v = userdata;
1836
1837 assert(s);
1838 assert(v);
1839
1840 handle_revents(v, revents);
1841 (void) varlink_process(v);
1842
1843 return 1;
1844 }
1845
1846 static int time_callback(sd_event_source *s, uint64_t usec, void *userdata) {
1847 Varlink *v = userdata;
1848
1849 assert(s);
1850 assert(v);
1851
1852 (void) varlink_process(v);
1853 return 1;
1854 }
1855
1856 static int defer_callback(sd_event_source *s, void *userdata) {
1857 Varlink *v = userdata;
1858
1859 assert(s);
1860 assert(v);
1861
1862 (void) varlink_process(v);
1863 return 1;
1864 }
1865
1866 static int prepare_callback(sd_event_source *s, void *userdata) {
1867 Varlink *v = userdata;
1868 int r, e;
1869 usec_t until;
1870 bool have_timeout;
1871
1872 assert(s);
1873 assert(v);
1874
1875 e = varlink_get_events(v);
1876 if (e < 0)
1877 return e;
1878
1879 r = sd_event_source_set_io_events(v->io_event_source, e);
1880 if (r < 0)
1881 return varlink_log_errno(v, r, "Failed to set source events: %m");
1882
1883 r = varlink_get_timeout(v, &until);
1884 if (r < 0)
1885 return r;
1886 have_timeout = r > 0;
1887
1888 if (have_timeout) {
1889 r = sd_event_source_set_time(v->time_event_source, until);
1890 if (r < 0)
1891 return varlink_log_errno(v, r, "Failed to set source time: %m");
1892 }
1893
1894 r = sd_event_source_set_enabled(v->time_event_source, have_timeout ? SD_EVENT_ON : SD_EVENT_OFF);
1895 if (r < 0)
1896 return varlink_log_errno(v, r, "Failed to enable event source: %m");
1897
1898 return 1;
1899 }
1900
1901 static int quit_callback(sd_event_source *event, void *userdata) {
1902 Varlink *v = userdata;
1903
1904 assert(event);
1905 assert(v);
1906
1907 varlink_flush(v);
1908 varlink_close(v);
1909
1910 return 1;
1911 }
1912
1913 int varlink_attach_event(Varlink *v, sd_event *e, int64_t priority) {
1914 int r;
1915
1916 assert_return(v, -EINVAL);
1917 assert_return(!v->event, -EBUSY);
1918
1919 if (e)
1920 v->event = sd_event_ref(e);
1921 else {
1922 r = sd_event_default(&v->event);
1923 if (r < 0)
1924 return varlink_log_errno(v, r, "Failed to create event source: %m");
1925 }
1926
1927 r = sd_event_add_time(v->event, &v->time_event_source, CLOCK_MONOTONIC, 0, 0, time_callback, v);
1928 if (r < 0)
1929 goto fail;
1930
1931 r = sd_event_source_set_priority(v->time_event_source, priority);
1932 if (r < 0)
1933 goto fail;
1934
1935 (void) sd_event_source_set_description(v->time_event_source, "varlink-time");
1936
1937 r = sd_event_add_exit(v->event, &v->quit_event_source, quit_callback, v);
1938 if (r < 0)
1939 goto fail;
1940
1941 r = sd_event_source_set_priority(v->quit_event_source, priority);
1942 if (r < 0)
1943 goto fail;
1944
1945 (void) sd_event_source_set_description(v->quit_event_source, "varlink-quit");
1946
1947 r = sd_event_add_io(v->event, &v->io_event_source, v->fd, 0, io_callback, v);
1948 if (r < 0)
1949 goto fail;
1950
1951 r = sd_event_source_set_prepare(v->io_event_source, prepare_callback);
1952 if (r < 0)
1953 goto fail;
1954
1955 r = sd_event_source_set_priority(v->io_event_source, priority);
1956 if (r < 0)
1957 goto fail;
1958
1959 (void) sd_event_source_set_description(v->io_event_source, "varlink-io");
1960
1961 r = sd_event_add_defer(v->event, &v->defer_event_source, defer_callback, v);
1962 if (r < 0)
1963 goto fail;
1964
1965 r = sd_event_source_set_priority(v->defer_event_source, priority);
1966 if (r < 0)
1967 goto fail;
1968
1969 (void) sd_event_source_set_description(v->defer_event_source, "varlink-defer");
1970
1971 return 0;
1972
1973 fail:
1974 varlink_log_errno(v, r, "Failed to setup event source: %m");
1975 varlink_detach_event(v);
1976 return r;
1977 }
1978
1979 void varlink_detach_event(Varlink *v) {
1980 if (!v)
1981 return;
1982
1983 varlink_detach_event_sources(v);
1984
1985 v->event = sd_event_unref(v->event);
1986 }
1987
1988 sd_event *varlink_get_event(Varlink *v) {
1989 assert_return(v, NULL);
1990
1991 return v->event;
1992 }
1993
1994 int varlink_server_new(VarlinkServer **ret, VarlinkServerFlags flags) {
1995 VarlinkServer *s;
1996
1997 assert_return(ret, -EINVAL);
1998 assert_return((flags & ~_VARLINK_SERVER_FLAGS_ALL) == 0, -EINVAL);
1999
2000 s = new(VarlinkServer, 1);
2001 if (!s)
2002 return log_oom_debug();
2003
2004 *s = (VarlinkServer) {
2005 .n_ref = 1,
2006 .flags = flags,
2007 .connections_max = varlink_server_connections_max(NULL),
2008 .connections_per_uid_max = varlink_server_connections_per_uid_max(NULL),
2009 };
2010
2011 *ret = s;
2012 return 0;
2013 }
2014
2015 static VarlinkServer* varlink_server_destroy(VarlinkServer *s) {
2016 char *m;
2017
2018 if (!s)
2019 return NULL;
2020
2021 varlink_server_shutdown(s);
2022
2023 while ((m = hashmap_steal_first_key(s->methods)))
2024 free(m);
2025
2026 hashmap_free(s->methods);
2027 hashmap_free(s->by_uid);
2028
2029 sd_event_unref(s->event);
2030
2031 free(s->description);
2032
2033 return mfree(s);
2034 }
2035
2036 DEFINE_TRIVIAL_REF_UNREF_FUNC(VarlinkServer, varlink_server, varlink_server_destroy);
2037
2038 static int validate_connection(VarlinkServer *server, const struct ucred *ucred) {
2039 int allowed = -1;
2040
2041 assert(server);
2042 assert(ucred);
2043
2044 if (FLAGS_SET(server->flags, VARLINK_SERVER_ROOT_ONLY))
2045 allowed = ucred->uid == 0;
2046
2047 if (FLAGS_SET(server->flags, VARLINK_SERVER_MYSELF_ONLY))
2048 allowed = allowed > 0 || ucred->uid == getuid();
2049
2050 if (allowed == 0) { /* Allow access when it is explicitly allowed or when neither
2051 * VARLINK_SERVER_ROOT_ONLY nor VARLINK_SERVER_MYSELF_ONLY are specified. */
2052 varlink_server_log(server, "Unprivileged client attempted connection, refusing.");
2053 return 0;
2054 }
2055
2056 if (server->n_connections >= server->connections_max) {
2057 varlink_server_log(server, "Connection limit of %u reached, refusing.", server->connections_max);
2058 return 0;
2059 }
2060
2061 if (FLAGS_SET(server->flags, VARLINK_SERVER_ACCOUNT_UID)) {
2062 unsigned c;
2063
2064 if (!uid_is_valid(ucred->uid)) {
2065 varlink_server_log(server, "Client with invalid UID attempted connection, refusing.");
2066 return 0;
2067 }
2068
2069 c = PTR_TO_UINT(hashmap_get(server->by_uid, UID_TO_PTR(ucred->uid)));
2070 if (c >= server->connections_per_uid_max) {
2071 varlink_server_log(server, "Per-UID connection limit of %u reached, refusing.",
2072 server->connections_per_uid_max);
2073 return 0;
2074 }
2075 }
2076
2077 return 1;
2078 }
2079
2080 static int count_connection(VarlinkServer *server, struct ucred *ucred) {
2081 unsigned c;
2082 int r;
2083
2084 assert(server);
2085 assert(ucred);
2086
2087 server->n_connections++;
2088
2089 if (FLAGS_SET(server->flags, VARLINK_SERVER_ACCOUNT_UID)) {
2090 r = hashmap_ensure_allocated(&server->by_uid, NULL);
2091 if (r < 0)
2092 return log_debug_errno(r, "Failed to allocate UID hash table: %m");
2093
2094 c = PTR_TO_UINT(hashmap_get(server->by_uid, UID_TO_PTR(ucred->uid)));
2095
2096 varlink_server_log(server, "Connections of user " UID_FMT ": %u (of %u max)",
2097 ucred->uid, c, server->connections_per_uid_max);
2098
2099 r = hashmap_replace(server->by_uid, UID_TO_PTR(ucred->uid), UINT_TO_PTR(c + 1));
2100 if (r < 0)
2101 return log_debug_errno(r, "Failed to increment counter in UID hash table: %m");
2102 }
2103
2104 return 0;
2105 }
2106
2107 int varlink_server_add_connection(VarlinkServer *server, int fd, Varlink **ret) {
2108 _cleanup_(varlink_unrefp) Varlink *v = NULL;
2109 bool ucred_acquired;
2110 struct ucred ucred;
2111 int r;
2112
2113 assert_return(server, -EINVAL);
2114 assert_return(fd >= 0, -EBADF);
2115
2116 if ((server->flags & (VARLINK_SERVER_ROOT_ONLY|VARLINK_SERVER_ACCOUNT_UID)) != 0) {
2117 r = getpeercred(fd, &ucred);
2118 if (r < 0)
2119 return varlink_server_log_errno(server, r, "Failed to acquire peer credentials of incoming socket, refusing: %m");
2120
2121 ucred_acquired = true;
2122
2123 r = validate_connection(server, &ucred);
2124 if (r < 0)
2125 return r;
2126 if (r == 0)
2127 return -EPERM;
2128 } else
2129 ucred_acquired = false;
2130
2131 r = varlink_new(&v);
2132 if (r < 0)
2133 return varlink_server_log_errno(server, r, "Failed to allocate connection object: %m");
2134
2135 r = count_connection(server, &ucred);
2136 if (r < 0)
2137 return r;
2138
2139 v->fd = fd;
2140 if (server->flags & VARLINK_SERVER_INHERIT_USERDATA)
2141 v->userdata = server->userdata;
2142
2143 if (ucred_acquired) {
2144 v->ucred = ucred;
2145 v->ucred_acquired = true;
2146 }
2147
2148 _cleanup_free_ char *desc = NULL;
2149 if (asprintf(&desc, "%s-%i", server->description ?: "varlink", v->fd) >= 0)
2150 v->description = TAKE_PTR(desc);
2151
2152 /* Link up the server and the connection, and take reference in both directions. Note that the
2153 * reference on the connection is left dangling. It will be dropped when the connection is closed,
2154 * which happens in varlink_close(), including in the event loop quit callback. */
2155 v->server = varlink_server_ref(server);
2156 varlink_ref(v);
2157
2158 varlink_set_state(v, VARLINK_IDLE_SERVER);
2159
2160 if (server->event) {
2161 r = varlink_attach_event(v, server->event, server->event_priority);
2162 if (r < 0) {
2163 varlink_log_errno(v, r, "Failed to attach new connection: %m");
2164 v->fd = -1; /* take the fd out of the connection again */
2165 varlink_close(v);
2166 return r;
2167 }
2168 }
2169
2170 if (ret)
2171 *ret = v;
2172
2173 return 0;
2174 }
2175
2176 static int connect_callback(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
2177 VarlinkServerSocket *ss = userdata;
2178 _cleanup_close_ int cfd = -1;
2179 Varlink *v = NULL;
2180 int r;
2181
2182 assert(source);
2183 assert(ss);
2184
2185 varlink_server_log(ss->server, "New incoming connection.");
2186
2187 cfd = accept4(fd, NULL, NULL, SOCK_NONBLOCK|SOCK_CLOEXEC);
2188 if (cfd < 0) {
2189 if (ERRNO_IS_ACCEPT_AGAIN(errno))
2190 return 0;
2191
2192 return varlink_server_log_errno(ss->server, errno, "Failed to accept incoming socket: %m");
2193 }
2194
2195 r = varlink_server_add_connection(ss->server, cfd, &v);
2196 if (r < 0)
2197 return 0;
2198
2199 TAKE_FD(cfd);
2200
2201 if (ss->server->connect_callback) {
2202 r = ss->server->connect_callback(ss->server, v, ss->server->userdata);
2203 if (r < 0) {
2204 varlink_log_errno(v, r, "Connection callback returned error, disconnecting client: %m");
2205 varlink_close(v);
2206 return 0;
2207 }
2208 }
2209
2210 return 0;
2211 }
2212
2213 int varlink_server_listen_fd(VarlinkServer *s, int fd) {
2214 _cleanup_free_ VarlinkServerSocket *ss = NULL;
2215 int r;
2216
2217 assert_return(s, -EINVAL);
2218 assert_return(fd >= 0, -EBADF);
2219
2220 r = fd_nonblock(fd, true);
2221 if (r < 0)
2222 return r;
2223
2224 ss = new(VarlinkServerSocket, 1);
2225 if (!ss)
2226 return log_oom_debug();
2227
2228 *ss = (VarlinkServerSocket) {
2229 .server = s,
2230 .fd = fd,
2231 };
2232
2233 if (s->event) {
2234 r = sd_event_add_io(s->event, &ss->event_source, fd, EPOLLIN, connect_callback, ss);
2235 if (r < 0)
2236 return r;
2237
2238 r = sd_event_source_set_priority(ss->event_source, s->event_priority);
2239 if (r < 0)
2240 return r;
2241 }
2242
2243 LIST_PREPEND(sockets, s->sockets, TAKE_PTR(ss));
2244 return 0;
2245 }
2246
2247 int varlink_server_listen_address(VarlinkServer *s, const char *address, mode_t m) {
2248 union sockaddr_union sockaddr;
2249 socklen_t sockaddr_len;
2250 _cleanup_close_ int fd = -1;
2251 int r;
2252
2253 assert_return(s, -EINVAL);
2254 assert_return(address, -EINVAL);
2255 assert_return((m & ~0777) == 0, -EINVAL);
2256
2257 r = sockaddr_un_set_path(&sockaddr.un, address);
2258 if (r < 0)
2259 return r;
2260 sockaddr_len = r;
2261
2262 fd = socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
2263 if (fd < 0)
2264 return -errno;
2265
2266 fd = fd_move_above_stdio(fd);
2267
2268 (void) sockaddr_un_unlink(&sockaddr.un);
2269
2270 RUN_WITH_UMASK(~m & 0777) {
2271 r = mac_selinux_bind(fd, &sockaddr.sa, sockaddr_len);
2272 if (r < 0)
2273 return r;
2274 }
2275
2276 if (listen(fd, SOMAXCONN) < 0)
2277 return -errno;
2278
2279 r = varlink_server_listen_fd(s, fd);
2280 if (r < 0)
2281 return r;
2282
2283 TAKE_FD(fd);
2284 return 0;
2285 }
2286
2287 void* varlink_server_set_userdata(VarlinkServer *s, void *userdata) {
2288 void *ret;
2289
2290 assert_return(s, NULL);
2291
2292 ret = s->userdata;
2293 s->userdata = userdata;
2294
2295 return ret;
2296 }
2297
2298 void* varlink_server_get_userdata(VarlinkServer *s) {
2299 assert_return(s, NULL);
2300
2301 return s->userdata;
2302 }
2303
2304 static VarlinkServerSocket* varlink_server_socket_destroy(VarlinkServerSocket *ss) {
2305 if (!ss)
2306 return NULL;
2307
2308 if (ss->server)
2309 LIST_REMOVE(sockets, ss->server->sockets, ss);
2310
2311 sd_event_source_disable_unref(ss->event_source);
2312
2313 free(ss->address);
2314 safe_close(ss->fd);
2315
2316 return mfree(ss);
2317 }
2318
2319 int varlink_server_shutdown(VarlinkServer *s) {
2320 assert_return(s, -EINVAL);
2321
2322 while (s->sockets)
2323 varlink_server_socket_destroy(s->sockets);
2324
2325 return 0;
2326 }
2327
2328 int varlink_server_attach_event(VarlinkServer *s, sd_event *e, int64_t priority) {
2329 VarlinkServerSocket *ss;
2330 int r;
2331
2332 assert_return(s, -EINVAL);
2333 assert_return(!s->event, -EBUSY);
2334
2335 if (e)
2336 s->event = sd_event_ref(e);
2337 else {
2338 r = sd_event_default(&s->event);
2339 if (r < 0)
2340 return r;
2341 }
2342
2343 LIST_FOREACH(sockets, ss, s->sockets) {
2344 assert(!ss->event_source);
2345
2346 r = sd_event_add_io(s->event, &ss->event_source, ss->fd, EPOLLIN, connect_callback, ss);
2347 if (r < 0)
2348 goto fail;
2349
2350 r = sd_event_source_set_priority(ss->event_source, priority);
2351 if (r < 0)
2352 goto fail;
2353 }
2354
2355 s->event_priority = priority;
2356 return 0;
2357
2358 fail:
2359 varlink_server_detach_event(s);
2360 return r;
2361 }
2362
2363 int varlink_server_detach_event(VarlinkServer *s) {
2364 VarlinkServerSocket *ss;
2365
2366 assert_return(s, -EINVAL);
2367
2368 LIST_FOREACH(sockets, ss, s->sockets) {
2369
2370 if (!ss->event_source)
2371 continue;
2372
2373 (void) sd_event_source_set_enabled(ss->event_source, SD_EVENT_OFF);
2374 ss->event_source = sd_event_source_unref(ss->event_source);
2375 }
2376
2377 sd_event_unref(s->event);
2378 return 0;
2379 }
2380
2381 sd_event *varlink_server_get_event(VarlinkServer *s) {
2382 assert_return(s, NULL);
2383
2384 return s->event;
2385 }
2386
2387 int varlink_server_bind_method(VarlinkServer *s, const char *method, VarlinkMethod callback) {
2388 _cleanup_free_ char *m = NULL;
2389 int r;
2390
2391 assert_return(s, -EINVAL);
2392 assert_return(method, -EINVAL);
2393 assert_return(callback, -EINVAL);
2394
2395 if (startswith(method, "org.varlink.service."))
2396 return log_debug_errno(SYNTHETIC_ERRNO(EEXIST), "Cannot bind server to '%s'.", method);
2397
2398 m = strdup(method);
2399 if (!m)
2400 return log_oom_debug();
2401
2402 r = hashmap_ensure_put(&s->methods, &string_hash_ops, m, callback);
2403 if (r == -ENOMEM)
2404 return log_oom_debug();
2405 if (r < 0)
2406 return log_debug_errno(r, "Failed to register callback: %m");
2407 if (r > 0)
2408 TAKE_PTR(m);
2409
2410 return 0;
2411 }
2412
2413 int varlink_server_bind_method_many_internal(VarlinkServer *s, ...) {
2414 va_list ap;
2415 int r = 0;
2416
2417 assert_return(s, -EINVAL);
2418
2419 va_start(ap, s);
2420 for (;;) {
2421 VarlinkMethod callback;
2422 const char *method;
2423
2424 method = va_arg(ap, const char *);
2425 if (!method)
2426 break;
2427
2428 callback = va_arg(ap, VarlinkMethod);
2429
2430 r = varlink_server_bind_method(s, method, callback);
2431 if (r < 0)
2432 break;
2433 }
2434 va_end(ap);
2435
2436 return r;
2437 }
2438
2439 int varlink_server_bind_connect(VarlinkServer *s, VarlinkConnect callback) {
2440 assert_return(s, -EINVAL);
2441
2442 if (callback && s->connect_callback && callback != s->connect_callback)
2443 return log_debug_errno(SYNTHETIC_ERRNO(EBUSY), "A different callback was already set.");
2444
2445 s->connect_callback = callback;
2446 return 0;
2447 }
2448
2449 int varlink_server_bind_disconnect(VarlinkServer *s, VarlinkDisconnect callback) {
2450 assert_return(s, -EINVAL);
2451
2452 if (callback && s->disconnect_callback && callback != s->disconnect_callback)
2453 return log_debug_errno(SYNTHETIC_ERRNO(EBUSY), "A different callback was already set.");
2454
2455 s->disconnect_callback = callback;
2456 return 0;
2457 }
2458
2459 unsigned varlink_server_connections_max(VarlinkServer *s) {
2460 int dts;
2461
2462 /* If a server is specified, return the setting for that server, otherwise the default value */
2463 if (s)
2464 return s->connections_max;
2465
2466 dts = getdtablesize();
2467 assert_se(dts > 0);
2468
2469 /* Make sure we never use up more than ¾th of RLIMIT_NOFILE for IPC */
2470 if (VARLINK_DEFAULT_CONNECTIONS_MAX > (unsigned) dts / 4 * 3)
2471 return dts / 4 * 3;
2472
2473 return VARLINK_DEFAULT_CONNECTIONS_MAX;
2474 }
2475
2476 unsigned varlink_server_connections_per_uid_max(VarlinkServer *s) {
2477 unsigned m;
2478
2479 if (s)
2480 return s->connections_per_uid_max;
2481
2482 /* Make sure to never use up more than ¾th of available connections for a single user */
2483 m = varlink_server_connections_max(NULL);
2484 if (VARLINK_DEFAULT_CONNECTIONS_PER_UID_MAX > m)
2485 return m / 4 * 3;
2486
2487 return VARLINK_DEFAULT_CONNECTIONS_PER_UID_MAX;
2488 }
2489
2490 int varlink_server_set_connections_per_uid_max(VarlinkServer *s, unsigned m) {
2491 assert_return(s, -EINVAL);
2492 assert_return(m > 0, -EINVAL);
2493
2494 s->connections_per_uid_max = m;
2495 return 0;
2496 }
2497
2498 int varlink_server_set_connections_max(VarlinkServer *s, unsigned m) {
2499 assert_return(s, -EINVAL);
2500 assert_return(m > 0, -EINVAL);
2501
2502 s->connections_max = m;
2503 return 0;
2504 }
2505
2506 unsigned varlink_server_current_connections(VarlinkServer *s) {
2507 assert_return(s, UINT_MAX);
2508
2509 return s->n_connections;
2510 }
2511
2512 int varlink_server_set_description(VarlinkServer *s, const char *description) {
2513 assert_return(s, -EINVAL);
2514
2515 return free_and_strdup(&s->description, description);
2516 }
Unnamed repository; edit this file 'description' to name the repository.