]> git.ipfire.org Git - thirdparty/systemd.git/blob - src/shared/varlink.c
projects / thirdparty / systemd.git / blob
? search:
summary | shortlog | log | commit | commitdiff | tree
blame | history | raw | HEAD
varlink: refactor adding socket event source to the event loop
[thirdparty/systemd.git] / src / shared / varlink.c
1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
2
3 #include <malloc.h>
4 #include <poll.h>
5
6 #include "alloc-util.h"
7 #include "errno-util.h"
8 #include "fd-util.h"
9 #include "glyph-util.h"
10 #include "hashmap.h"
11 #include "io-util.h"
12 #include "list.h"
13 #include "process-util.h"
14 #include "selinux-util.h"
15 #include "set.h"
16 #include "socket-util.h"
17 #include "string-table.h"
18 #include "string-util.h"
19 #include "strv.h"
20 #include "time-util.h"
21 #include "umask-util.h"
22 #include "user-util.h"
23 #include "varlink.h"
24
25 #define VARLINK_DEFAULT_CONNECTIONS_MAX 4096U
26 #define VARLINK_DEFAULT_CONNECTIONS_PER_UID_MAX 1024U
27
28 #define VARLINK_DEFAULT_TIMEOUT_USEC (45U*USEC_PER_SEC)
29 #define VARLINK_BUFFER_MAX (16U*1024U*1024U)
30 #define VARLINK_READ_SIZE (64U*1024U)
31
32 typedef enum VarlinkState {
33 /* Client side states */
34 VARLINK_IDLE_CLIENT,
35 VARLINK_AWAITING_REPLY,
36 VARLINK_AWAITING_REPLY_MORE,
37 VARLINK_CALLING,
38 VARLINK_CALLED,
39 VARLINK_PROCESSING_REPLY,
40
41 /* Server side states */
42 VARLINK_IDLE_SERVER,
43 VARLINK_PROCESSING_METHOD,
44 VARLINK_PROCESSING_METHOD_MORE,
45 VARLINK_PROCESSING_METHOD_ONEWAY,
46 VARLINK_PROCESSED_METHOD,
47 VARLINK_PENDING_METHOD,
48 VARLINK_PENDING_METHOD_MORE,
49
50 /* Common states (only during shutdown) */
51 VARLINK_PENDING_DISCONNECT,
52 VARLINK_PENDING_TIMEOUT,
53 VARLINK_PROCESSING_DISCONNECT,
54 VARLINK_PROCESSING_TIMEOUT,
55 VARLINK_PROCESSING_FAILURE,
56 VARLINK_DISCONNECTED,
57
58 _VARLINK_STATE_MAX,
59 _VARLINK_STATE_INVALID = -EINVAL,
60 } VarlinkState;
61
62 /* Tests whether we are not yet disconnected. Note that this is true during all states where the connection
63 * is still good for something, and false only when it's dead for good. This means: when we are
64 * asynchronously connecting to a peer and the connect() is still pending, then this will return 'true', as
65 * the connection is still good, and we are likely to be able to properly operate on it soon. */
66 #define VARLINK_STATE_IS_ALIVE(state) \
67 IN_SET(state, \
68 VARLINK_IDLE_CLIENT, \
69 VARLINK_AWAITING_REPLY, \
70 VARLINK_AWAITING_REPLY_MORE, \
71 VARLINK_CALLING, \
72 VARLINK_CALLED, \
73 VARLINK_PROCESSING_REPLY, \
74 VARLINK_IDLE_SERVER, \
75 VARLINK_PROCESSING_METHOD, \
76 VARLINK_PROCESSING_METHOD_MORE, \
77 VARLINK_PROCESSING_METHOD_ONEWAY, \
78 VARLINK_PROCESSED_METHOD, \
79 VARLINK_PENDING_METHOD, \
80 VARLINK_PENDING_METHOD_MORE)
81
82 struct Varlink {
83 unsigned n_ref;
84
85 VarlinkServer *server;
86
87 VarlinkState state;
88 bool connecting; /* This boolean indicates whether the socket fd we are operating on is currently
89 * processing an asynchronous connect(). In that state we watch the socket for
90 * EPOLLOUT, but we refrain from calling read() or write() on the socket as that
91 * will trigger ENOTCONN. Note that this boolean is kept separate from the
92 * VarlinkState above on purpose: while the connect() is still not complete we
93 * already want to allow queuing of messages and similar. Thus it's nice to keep
94 * these two state concepts separate: the VarlinkState encodes what our own view of
95 * the connection is, i.e. whether we think it's a server, a client, and has
96 * something queued already, while 'connecting' tells us a detail about the
97 * transport used below, that should have no effect on how we otherwise accept and
98 * process operations from the user.
99 *
100 * Or to say this differently: VARLINK_STATE_IS_ALIVE(state) tells you whether the
101 * connection is good to use, even if it might not be fully connected
102 * yet. connecting=true then informs you that actually we are still connecting, and
103 * the connection is actually not established yet and thus any requests you enqueue
104 * now will still work fine but will be queued only, not sent yet, but that
105 * shouldn't stop you from using the connection, since eventually whatever you queue
106 * *will* be sent.
107 *
108 * Or to say this even differently: 'state' is a high-level ("application layer"
109 * high, if you so will) state, while 'conecting' is a low-level ("transport layer"
110 * low, if you so will) state, and while they are not entirely unrelated and
111 * sometimes propagate effects to each other they are only asynchronously connected
112 * at most. */
113 unsigned n_pending;
114
115 int fd;
116
117 char *input_buffer; /* valid data starts at input_buffer_index, ends at input_buffer_index+input_buffer_size */
118 size_t input_buffer_index;
119 size_t input_buffer_size;
120 size_t input_buffer_unscanned;
121
122 char *output_buffer; /* valid data starts at output_buffer_index, ends at output_buffer_index+output_buffer_size */
123 size_t output_buffer_index;
124 size_t output_buffer_size;
125
126 VarlinkReply reply_callback;
127
128 JsonVariant *current;
129 JsonVariant *reply;
130
131 struct ucred ucred;
132 bool ucred_acquired:1;
133
134 bool write_disconnected:1;
135 bool read_disconnected:1;
136 bool prefer_read_write:1;
137 bool got_pollhup:1;
138
139 usec_t timestamp;
140 usec_t timeout;
141
142 void *userdata;
143 char *description;
144
145 sd_event *event;
146 sd_event_source *io_event_source;
147 sd_event_source *time_event_source;
148 sd_event_source *quit_event_source;
149 sd_event_source *defer_event_source;
150 };
151
152 typedef struct VarlinkServerSocket VarlinkServerSocket;
153
154 struct VarlinkServerSocket {
155 VarlinkServer *server;
156
157 int fd;
158 char *address;
159
160 sd_event_source *event_source;
161
162 LIST_FIELDS(VarlinkServerSocket, sockets);
163 };
164
165 struct VarlinkServer {
166 unsigned n_ref;
167 VarlinkServerFlags flags;
168
169 LIST_HEAD(VarlinkServerSocket, sockets);
170
171 Hashmap *methods;
172 VarlinkConnect connect_callback;
173 VarlinkDisconnect disconnect_callback;
174
175 sd_event *event;
176 int64_t event_priority;
177
178 unsigned n_connections;
179 Hashmap *by_uid;
180
181 void *userdata;
182 char *description;
183
184 unsigned connections_max;
185 unsigned connections_per_uid_max;
186 };
187
188 static const char* const varlink_state_table[_VARLINK_STATE_MAX] = {
189 [VARLINK_IDLE_CLIENT] = "idle-client",
190 [VARLINK_AWAITING_REPLY] = "awaiting-reply",
191 [VARLINK_AWAITING_REPLY_MORE] = "awaiting-reply-more",
192 [VARLINK_CALLING] = "calling",
193 [VARLINK_CALLED] = "called",
194 [VARLINK_PROCESSING_REPLY] = "processing-reply",
195 [VARLINK_IDLE_SERVER] = "idle-server",
196 [VARLINK_PROCESSING_METHOD] = "processing-method",
197 [VARLINK_PROCESSING_METHOD_MORE] = "processing-method-more",
198 [VARLINK_PROCESSING_METHOD_ONEWAY] = "processing-method-oneway",
199 [VARLINK_PROCESSED_METHOD] = "processed-method",
200 [VARLINK_PENDING_METHOD] = "pending-method",
201 [VARLINK_PENDING_METHOD_MORE] = "pending-method-more",
202 [VARLINK_PENDING_DISCONNECT] = "pending-disconnect",
203 [VARLINK_PENDING_TIMEOUT] = "pending-timeout",
204 [VARLINK_PROCESSING_DISCONNECT] = "processing-disconnect",
205 [VARLINK_PROCESSING_TIMEOUT] = "processing-timeout",
206 [VARLINK_PROCESSING_FAILURE] = "processing-failure",
207 [VARLINK_DISCONNECTED] = "disconnected",
208 };
209
210 DEFINE_PRIVATE_STRING_TABLE_LOOKUP_TO_STRING(varlink_state, VarlinkState);
211
212 #define varlink_log_errno(v, error, fmt, ...) \
213 log_debug_errno(error, "%s: " fmt, varlink_description(v), ##__VA_ARGS__)
214
215 #define varlink_log(v, fmt, ...) \
216 log_debug("%s: " fmt, varlink_description(v), ##__VA_ARGS__)
217
218 #define varlink_server_log_errno(s, error, fmt, ...) \
219 log_debug_errno(error, "%s: " fmt, varlink_server_description(s), ##__VA_ARGS__)
220
221 #define varlink_server_log(s, fmt, ...) \
222 log_debug("%s: " fmt, varlink_server_description(s), ##__VA_ARGS__)
223
224 static inline const char *varlink_description(Varlink *v) {
225 return (v ? v->description : NULL) ?: "varlink";
226 }
227
228 static inline const char *varlink_server_description(VarlinkServer *s) {
229 return (s ? s->description : NULL) ?: "varlink";
230 }
231
232 static void varlink_set_state(Varlink *v, VarlinkState state) {
233 assert(v);
234 assert(state >= 0 && state < _VARLINK_STATE_MAX);
235
236 if (v->state < 0)
237 varlink_log(v, "Setting state %s",
238 varlink_state_to_string(state));
239 else
240 varlink_log(v, "Changing state %s %s %s",
241 varlink_state_to_string(v->state),
242 special_glyph(SPECIAL_GLYPH_ARROW_RIGHT),
243 varlink_state_to_string(state));
244
245 v->state = state;
246 }
247
248 static int varlink_new(Varlink **ret) {
249 Varlink *v;
250
251 assert(ret);
252
253 v = new(Varlink, 1);
254 if (!v)
255 return -ENOMEM;
256
257 *v = (Varlink) {
258 .n_ref = 1,
259 .fd = -1,
260
261 .state = _VARLINK_STATE_INVALID,
262
263 .ucred = UCRED_INVALID,
264
265 .timestamp = USEC_INFINITY,
266 .timeout = VARLINK_DEFAULT_TIMEOUT_USEC
267 };
268
269 *ret = v;
270 return 0;
271 }
272
273 int varlink_connect_address(Varlink **ret, const char *address) {
274 _cleanup_(varlink_unrefp) Varlink *v = NULL;
275 union sockaddr_union sockaddr;
276 int r;
277
278 assert_return(ret, -EINVAL);
279 assert_return(address, -EINVAL);
280
281 r = varlink_new(&v);
282 if (r < 0)
283 return log_debug_errno(r, "Failed to create varlink object: %m");
284
285 v->fd = socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
286 if (v->fd < 0)
287 return log_debug_errno(errno, "Failed to create AF_UNIX socket: %m");
288
289 v->fd = fd_move_above_stdio(v->fd);
290
291 r = sockaddr_un_set_path(&sockaddr.un, address);
292 if (r < 0) {
293 if (r != -ENAMETOOLONG)
294 return log_debug_errno(r, "Failed to set socket address '%s': %m", address);
295
296 /* This is a file system path, and too long to fit into sockaddr_un. Let's connect via O_PATH
297 * to this socket. */
298
299 r = connect_unix_path(v->fd, AT_FDCWD, address);
300 } else
301 r = RET_NERRNO(connect(v->fd, &sockaddr.sa, r));
302
303 if (r < 0) {
304 if (!IN_SET(r, -EAGAIN, -EINPROGRESS))
305 return log_debug_errno(r, "Failed to connect to %s: %m", address);
306
307 v->connecting = true; /* We are asynchronously connecting, i.e. the connect() is being
308 * processed in the background. As long as that's the case the socket
309 * is in a special state: it's there, we can poll it for EPOLLOUT, but
310 * if we attempt to write() to it before we see EPOLLOUT we'll get
311 * ENOTCONN (and not EAGAIN, like we would for a normal connected
312 * socket that isn't writable at the moment). Since ENOTCONN on write()
313 * hence can mean two different things (i.e. connection not complete
314 * yet vs. already disconnected again), we store as a boolean whether
315 * we are still in connect(). */
316 }
317
318 varlink_set_state(v, VARLINK_IDLE_CLIENT);
319
320 *ret = TAKE_PTR(v);
321 return 0;
322 }
323
324 int varlink_connect_fd(Varlink **ret, int fd) {
325 Varlink *v;
326 int r;
327
328 assert_return(ret, -EINVAL);
329 assert_return(fd >= 0, -EBADF);
330
331 r = fd_nonblock(fd, true);
332 if (r < 0)
333 return log_debug_errno(r, "Failed to make fd %d nonblocking: %m", fd);
334
335 r = varlink_new(&v);
336 if (r < 0)
337 return log_debug_errno(r, "Failed to create varlink object: %m");
338
339 v->fd = fd;
340 varlink_set_state(v, VARLINK_IDLE_CLIENT);
341
342 /* Note that if this function is called we assume the passed socket (if it is one) is already
343 * properly connected, i.e. any asynchronous connect() done on it already completed. Because of that
344 * we'll not set the 'connecting' boolean here, i.e. we don't need to avoid write()ing to the socket
345 * until the connection is fully set up. Behaviour here is hence a bit different from
346 * varlink_connect_address() above, as there we do handle asynchronous connections ourselves and
347 * avoid doing write() on it before we saw EPOLLOUT for the first time. */
348
349 *ret = v;
350 return 0;
351 }
352
353 static void varlink_detach_event_sources(Varlink *v) {
354 assert(v);
355
356 v->io_event_source = sd_event_source_disable_unref(v->io_event_source);
357 v->time_event_source = sd_event_source_disable_unref(v->time_event_source);
358 v->quit_event_source = sd_event_source_disable_unref(v->quit_event_source);
359 v->defer_event_source = sd_event_source_disable_unref(v->defer_event_source);
360 }
361
362 static void varlink_clear(Varlink *v) {
363 assert(v);
364
365 varlink_detach_event_sources(v);
366
367 v->fd = safe_close(v->fd);
368
369 v->input_buffer = mfree(v->input_buffer);
370 v->output_buffer = mfree(v->output_buffer);
371
372 v->current = json_variant_unref(v->current);
373 v->reply = json_variant_unref(v->reply);
374
375 v->event = sd_event_unref(v->event);
376 }
377
378 static Varlink* varlink_destroy(Varlink *v) {
379 if (!v)
380 return NULL;
381
382 /* If this is called the server object must already been unreffed here. Why that? because when we
383 * linked up the varlink connection with the server object we took one ref in each direction */
384 assert(!v->server);
385
386 varlink_clear(v);
387
388 free(v->description);
389 return mfree(v);
390 }
391
392 DEFINE_TRIVIAL_REF_UNREF_FUNC(Varlink, varlink, varlink_destroy);
393
394 static int varlink_test_disconnect(Varlink *v) {
395 assert(v);
396
397 /* Tests whether we the connection has been terminated. We are careful to not stop processing it
398 * prematurely, since we want to handle half-open connections as well as possible and want to flush
399 * out and read data before we close down if we can. */
400
401 /* Already disconnected? */
402 if (!VARLINK_STATE_IS_ALIVE(v->state))
403 return 0;
404
405 /* Wait until connection setup is complete, i.e. until asynchronous connect() completes */
406 if (v->connecting)
407 return 0;
408
409 /* Still something to write and we can write? Stay around */
410 if (v->output_buffer_size > 0 && !v->write_disconnected)
411 return 0;
412
413 /* Both sides gone already? Then there's no need to stick around */
414 if (v->read_disconnected && v->write_disconnected)
415 goto disconnect;
416
417 /* If we are waiting for incoming data but the read side is shut down, disconnect. */
418 if (IN_SET(v->state, VARLINK_AWAITING_REPLY, VARLINK_AWAITING_REPLY_MORE, VARLINK_CALLING, VARLINK_IDLE_SERVER) && v->read_disconnected)
419 goto disconnect;
420
421 /* Similar, if are a client that hasn't written anything yet but the write side is dead, also
422 * disconnect. We also explicitly check for POLLHUP here since we likely won't notice the write side
423 * being down if we never wrote anything. */
424 if (IN_SET(v->state, VARLINK_IDLE_CLIENT) && (v->write_disconnected || v->got_pollhup))
425 goto disconnect;
426
427 /* We are on the server side and still want to send out more replies, but we saw POLLHUP already, and
428 * either got no buffered bytes to write anymore or already saw a write error. In that case we should
429 * shut down the varlink link. */
430 if (IN_SET(v->state, VARLINK_PENDING_METHOD, VARLINK_PENDING_METHOD_MORE) && (v->write_disconnected || v->output_buffer_size == 0) && v->got_pollhup)
431 goto disconnect;
432
433 return 0;
434
435 disconnect:
436 varlink_set_state(v, VARLINK_PENDING_DISCONNECT);
437 return 1;
438 }
439
440 static int varlink_write(Varlink *v) {
441 ssize_t n;
442
443 assert(v);
444
445 if (!VARLINK_STATE_IS_ALIVE(v->state))
446 return 0;
447 if (v->connecting) /* Writing while we are still wait for a non-blocking connect() to complete will
448 * result in ENOTCONN, hence exit early here */
449 return 0;
450 if (v->output_buffer_size == 0)
451 return 0;
452 if (v->write_disconnected)
453 return 0;
454
455 assert(v->fd >= 0);
456
457 /* We generally prefer recv()/send() (mostly because of MSG_NOSIGNAL) but also want to be compatible
458 * with non-socket IO, hence fall back automatically.
459 *
460 * Use a local variable to help gcc figure out that we set 'n' in all cases. */
461 bool prefer_write = v->prefer_read_write;
462 if (!prefer_write) {
463 n = send(v->fd, v->output_buffer + v->output_buffer_index, v->output_buffer_size, MSG_DONTWAIT|MSG_NOSIGNAL);
464 if (n < 0 && errno == ENOTSOCK)
465 prefer_write = v->prefer_read_write = true;
466 }
467 if (prefer_write)
468 n = write(v->fd, v->output_buffer + v->output_buffer_index, v->output_buffer_size);
469 if (n < 0) {
470 if (errno == EAGAIN)
471 return 0;
472
473 if (ERRNO_IS_DISCONNECT(errno)) {
474 /* If we get informed about a disconnect on write, then let's remember that, but not
475 * act on it just yet. Let's wait for read() to report the issue first. */
476 v->write_disconnected = true;
477 return 1;
478 }
479
480 return -errno;
481 }
482
483 v->output_buffer_size -= n;
484
485 if (v->output_buffer_size == 0)
486 v->output_buffer_index = 0;
487 else
488 v->output_buffer_index += n;
489
490 v->timestamp = now(CLOCK_MONOTONIC);
491 return 1;
492 }
493
494 static int varlink_read(Varlink *v) {
495 size_t rs;
496 ssize_t n;
497
498 assert(v);
499
500 if (!IN_SET(v->state, VARLINK_AWAITING_REPLY, VARLINK_AWAITING_REPLY_MORE, VARLINK_CALLING, VARLINK_IDLE_SERVER))
501 return 0;
502 if (v->connecting) /* read() on a socket while we are in connect() will fail with EINVAL, hence exit early here */
503 return 0;
504 if (v->current)
505 return 0;
506 if (v->input_buffer_unscanned > 0)
507 return 0;
508 if (v->read_disconnected)
509 return 0;
510
511 if (v->input_buffer_size >= VARLINK_BUFFER_MAX)
512 return -ENOBUFS;
513
514 assert(v->fd >= 0);
515
516 if (MALLOC_SIZEOF_SAFE(v->input_buffer) <= v->input_buffer_index + v->input_buffer_size) {
517 size_t add;
518
519 add = MIN(VARLINK_BUFFER_MAX - v->input_buffer_size, VARLINK_READ_SIZE);
520
521 if (v->input_buffer_index == 0) {
522
523 if (!GREEDY_REALLOC(v->input_buffer, v->input_buffer_size + add))
524 return -ENOMEM;
525
526 } else {
527 char *b;
528
529 b = new(char, v->input_buffer_size + add);
530 if (!b)
531 return -ENOMEM;
532
533 memcpy(b, v->input_buffer + v->input_buffer_index, v->input_buffer_size);
534
535 free_and_replace(v->input_buffer, b);
536 v->input_buffer_index = 0;
537 }
538 }
539
540 rs = MALLOC_SIZEOF_SAFE(v->input_buffer) - (v->input_buffer_index + v->input_buffer_size);
541
542 bool prefer_read = v->prefer_read_write;
543 if (!prefer_read) {
544 n = recv(v->fd, v->input_buffer + v->input_buffer_index + v->input_buffer_size, rs, MSG_DONTWAIT);
545 if (n < 0 && errno == ENOTSOCK)
546 prefer_read = v->prefer_read_write = true;
547 }
548 if (prefer_read)
549 n = read(v->fd, v->input_buffer + v->input_buffer_index + v->input_buffer_size, rs);
550 if (n < 0) {
551 if (errno == EAGAIN)
552 return 0;
553
554 if (ERRNO_IS_DISCONNECT(errno)) {
555 v->read_disconnected = true;
556 return 1;
557 }
558
559 return -errno;
560 }
561 if (n == 0) { /* EOF */
562 v->read_disconnected = true;
563 return 1;
564 }
565
566 v->input_buffer_size += n;
567 v->input_buffer_unscanned += n;
568
569 return 1;
570 }
571
572 static int varlink_parse_message(Varlink *v) {
573 const char *e, *begin;
574 size_t sz;
575 int r;
576
577 assert(v);
578
579 if (v->current)
580 return 0;
581 if (v->input_buffer_unscanned <= 0)
582 return 0;
583
584 assert(v->input_buffer_unscanned <= v->input_buffer_size);
585 assert(v->input_buffer_index + v->input_buffer_size <= MALLOC_SIZEOF_SAFE(v->input_buffer));
586
587 begin = v->input_buffer + v->input_buffer_index;
588
589 e = memchr(begin + v->input_buffer_size - v->input_buffer_unscanned, 0, v->input_buffer_unscanned);
590 if (!e) {
591 v->input_buffer_unscanned = 0;
592 return 0;
593 }
594
595 sz = e - begin + 1;
596
597 varlink_log(v, "New incoming message: %s", begin); /* FIXME: should we output the whole message here before validation?
598 * This may produce a non-printable journal entry if the message
599 * is invalid. We may also expose privileged information. */
600
601 r = json_parse(begin, 0, &v->current, NULL, NULL);
602 if (r < 0) {
603 /* If we encounter a parse failure flush all data. We cannot possibly recover from this,
604 * hence drop all buffered data now. */
605 v->input_buffer_index = v->input_buffer_size = v->input_buffer_unscanned = 0;
606 return varlink_log_errno(v, r, "Failed to parse JSON: %m");
607 }
608
609 v->input_buffer_size -= sz;
610
611 if (v->input_buffer_size == 0)
612 v->input_buffer_index = 0;
613 else
614 v->input_buffer_index += sz;
615
616 v->input_buffer_unscanned = v->input_buffer_size;
617 return 1;
618 }
619
620 static int varlink_test_timeout(Varlink *v) {
621 assert(v);
622
623 if (!IN_SET(v->state, VARLINK_AWAITING_REPLY, VARLINK_AWAITING_REPLY_MORE, VARLINK_CALLING))
624 return 0;
625 if (v->timeout == USEC_INFINITY)
626 return 0;
627
628 if (now(CLOCK_MONOTONIC) < usec_add(v->timestamp, v->timeout))
629 return 0;
630
631 varlink_set_state(v, VARLINK_PENDING_TIMEOUT);
632
633 return 1;
634 }
635
636 static int varlink_dispatch_local_error(Varlink *v, const char *error) {
637 int r;
638
639 assert(v);
640 assert(error);
641
642 if (!v->reply_callback)
643 return 0;
644
645 r = v->reply_callback(v, NULL, error, VARLINK_REPLY_ERROR|VARLINK_REPLY_LOCAL, v->userdata);
646 if (r < 0)
647 log_debug_errno(r, "Reply callback returned error, ignoring: %m");
648
649 return 1;
650 }
651
652 static int varlink_dispatch_timeout(Varlink *v) {
653 assert(v);
654
655 if (v->state != VARLINK_PENDING_TIMEOUT)
656 return 0;
657
658 varlink_set_state(v, VARLINK_PROCESSING_TIMEOUT);
659 varlink_dispatch_local_error(v, VARLINK_ERROR_TIMEOUT);
660 varlink_close(v);
661
662 return 1;
663 }
664
665 static int varlink_dispatch_disconnect(Varlink *v) {
666 assert(v);
667
668 if (v->state != VARLINK_PENDING_DISCONNECT)
669 return 0;
670
671 varlink_set_state(v, VARLINK_PROCESSING_DISCONNECT);
672 varlink_dispatch_local_error(v, VARLINK_ERROR_DISCONNECTED);
673 varlink_close(v);
674
675 return 1;
676 }
677
678 static int varlink_sanitize_parameters(JsonVariant **v) {
679 assert(v);
680
681 /* Varlink always wants a parameters list, hence make one if the caller doesn't want any */
682 if (!*v)
683 return json_variant_new_object(v, NULL, 0);
684 else if (!json_variant_is_object(*v))
685 return -EINVAL;
686
687 return 0;
688 }
689
690 static int varlink_dispatch_reply(Varlink *v) {
691 _cleanup_(json_variant_unrefp) JsonVariant *parameters = NULL;
692 VarlinkReplyFlags flags = 0;
693 const char *error = NULL;
694 JsonVariant *e;
695 const char *k;
696 int r;
697
698 assert(v);
699
700 if (!IN_SET(v->state, VARLINK_AWAITING_REPLY, VARLINK_AWAITING_REPLY_MORE, VARLINK_CALLING))
701 return 0;
702 if (!v->current)
703 return 0;
704
705 assert(v->n_pending > 0);
706
707 if (!json_variant_is_object(v->current))
708 goto invalid;
709
710 JSON_VARIANT_OBJECT_FOREACH(k, e, v->current) {
711
712 if (streq(k, "error")) {
713 if (error)
714 goto invalid;
715 if (!json_variant_is_string(e))
716 goto invalid;
717
718 error = json_variant_string(e);
719 flags |= VARLINK_REPLY_ERROR;
720
721 } else if (streq(k, "parameters")) {
722 if (parameters)
723 goto invalid;
724 if (!json_variant_is_object(e))
725 goto invalid;
726
727 parameters = json_variant_ref(e);
728
729 } else if (streq(k, "continues")) {
730 if (FLAGS_SET(flags, VARLINK_REPLY_CONTINUES))
731 goto invalid;
732
733 if (!json_variant_is_boolean(e))
734 goto invalid;
735
736 if (json_variant_boolean(e))
737 flags |= VARLINK_REPLY_CONTINUES;
738 } else
739 goto invalid;
740 }
741
742 /* Replies with 'continue' set are only OK if we set 'more' when the method call was initiated */
743 if (v->state != VARLINK_AWAITING_REPLY_MORE && FLAGS_SET(flags, VARLINK_REPLY_CONTINUES))
744 goto invalid;
745
746 /* An error is final */
747 if (error && FLAGS_SET(flags, VARLINK_REPLY_CONTINUES))
748 goto invalid;
749
750 r = varlink_sanitize_parameters(&parameters);
751 if (r < 0)
752 goto invalid;
753
754 if (IN_SET(v->state, VARLINK_AWAITING_REPLY, VARLINK_AWAITING_REPLY_MORE)) {
755 varlink_set_state(v, VARLINK_PROCESSING_REPLY);
756
757 if (v->reply_callback) {
758 r = v->reply_callback(v, parameters, error, flags, v->userdata);
759 if (r < 0)
760 log_debug_errno(r, "Reply callback returned error, ignoring: %m");
761 }
762
763 v->current = json_variant_unref(v->current);
764
765 if (v->state == VARLINK_PROCESSING_REPLY) {
766
767 assert(v->n_pending > 0);
768
769 if (!FLAGS_SET(flags, VARLINK_REPLY_CONTINUES))
770 v->n_pending--;
771
772 varlink_set_state(v,
773 FLAGS_SET(flags, VARLINK_REPLY_CONTINUES) ? VARLINK_AWAITING_REPLY_MORE :
774 v->n_pending == 0 ? VARLINK_IDLE_CLIENT : VARLINK_AWAITING_REPLY);
775 }
776 } else {
777 assert(v->state == VARLINK_CALLING);
778 varlink_set_state(v, VARLINK_CALLED);
779 }
780
781 return 1;
782
783 invalid:
784 varlink_set_state(v, VARLINK_PROCESSING_FAILURE);
785 varlink_dispatch_local_error(v, VARLINK_ERROR_PROTOCOL);
786 varlink_close(v);
787
788 return 1;
789 }
790
791 static int varlink_dispatch_method(Varlink *v) {
792 _cleanup_(json_variant_unrefp) JsonVariant *parameters = NULL;
793 VarlinkMethodFlags flags = 0;
794 const char *method = NULL, *error;
795 JsonVariant *e;
796 VarlinkMethod callback;
797 const char *k;
798 int r;
799
800 assert(v);
801
802 if (v->state != VARLINK_IDLE_SERVER)
803 return 0;
804 if (!v->current)
805 return 0;
806
807 if (!json_variant_is_object(v->current))
808 goto invalid;
809
810 JSON_VARIANT_OBJECT_FOREACH(k, e, v->current) {
811
812 if (streq(k, "method")) {
813 if (method)
814 goto invalid;
815 if (!json_variant_is_string(e))
816 goto invalid;
817
818 method = json_variant_string(e);
819
820 } else if (streq(k, "parameters")) {
821 if (parameters)
822 goto invalid;
823 if (!json_variant_is_object(e))
824 goto invalid;
825
826 parameters = json_variant_ref(e);
827
828 } else if (streq(k, "oneway")) {
829
830 if ((flags & (VARLINK_METHOD_ONEWAY|VARLINK_METHOD_MORE)) != 0)
831 goto invalid;
832
833 if (!json_variant_is_boolean(e))
834 goto invalid;
835
836 if (json_variant_boolean(e))
837 flags |= VARLINK_METHOD_ONEWAY;
838
839 } else if (streq(k, "more")) {
840
841 if ((flags & (VARLINK_METHOD_ONEWAY|VARLINK_METHOD_MORE)) != 0)
842 goto invalid;
843
844 if (!json_variant_is_boolean(e))
845 goto invalid;
846
847 if (json_variant_boolean(e))
848 flags |= VARLINK_METHOD_MORE;
849
850 } else
851 goto invalid;
852 }
853
854 if (!method)
855 goto invalid;
856
857 r = varlink_sanitize_parameters(&parameters);
858 if (r < 0)
859 goto fail;
860
861 varlink_set_state(v, (flags & VARLINK_METHOD_MORE) ? VARLINK_PROCESSING_METHOD_MORE :
862 (flags & VARLINK_METHOD_ONEWAY) ? VARLINK_PROCESSING_METHOD_ONEWAY :
863 VARLINK_PROCESSING_METHOD);
864
865 assert(v->server);
866
867 if (STR_IN_SET(method, "org.varlink.service.GetInfo", "org.varlink.service.GetInterface")) {
868 /* For now, we don't implement a single of varlink's own methods */
869 callback = NULL;
870 error = VARLINK_ERROR_METHOD_NOT_IMPLEMENTED;
871 } else if (startswith(method, "org.varlink.service.")) {
872 callback = NULL;
873 error = VARLINK_ERROR_METHOD_NOT_FOUND;
874 } else {
875 callback = hashmap_get(v->server->methods, method);
876 error = VARLINK_ERROR_METHOD_NOT_FOUND;
877 }
878
879 if (callback) {
880 r = callback(v, parameters, flags, v->userdata);
881 if (r < 0) {
882 log_debug_errno(r, "Callback for %s returned error: %m", method);
883
884 /* We got an error back from the callback. Propagate it to the client if the method call remains unanswered. */
885 if (!FLAGS_SET(flags, VARLINK_METHOD_ONEWAY)) {
886 r = varlink_error_errno(v, r);
887 if (r < 0)
888 return r;
889 }
890 }
891 } else if (!FLAGS_SET(flags, VARLINK_METHOD_ONEWAY)) {
892 assert(error);
893
894 r = varlink_errorb(v, error, JSON_BUILD_OBJECT(JSON_BUILD_PAIR("method", JSON_BUILD_STRING(method))));
895 if (r < 0)
896 return r;
897 }
898
899 switch (v->state) {
900
901 case VARLINK_PROCESSED_METHOD: /* Method call is fully processed */
902 case VARLINK_PROCESSING_METHOD_ONEWAY: /* ditto */
903 v->current = json_variant_unref(v->current);
904 varlink_set_state(v, VARLINK_IDLE_SERVER);
905 break;
906
907 case VARLINK_PROCESSING_METHOD: /* Method call wasn't replied to, will be replied to later */
908 varlink_set_state(v, VARLINK_PENDING_METHOD);
909 break;
910
911 case VARLINK_PROCESSING_METHOD_MORE: /* No reply for a "more" message was sent, more to come */
912 varlink_set_state(v, VARLINK_PENDING_METHOD_MORE);
913 break;
914
915 default:
916 assert_not_reached();
917
918 }
919
920 return r;
921
922 invalid:
923 r = -EINVAL;
924
925 fail:
926 varlink_set_state(v, VARLINK_PROCESSING_FAILURE);
927 varlink_dispatch_local_error(v, VARLINK_ERROR_PROTOCOL);
928 varlink_close(v);
929
930 return r;
931 }
932
933 int varlink_process(Varlink *v) {
934 int r;
935
936 assert_return(v, -EINVAL);
937
938 if (v->state == VARLINK_DISCONNECTED)
939 return varlink_log_errno(v, SYNTHETIC_ERRNO(ENOTCONN), "Not connected.");
940
941 varlink_ref(v);
942
943 r = varlink_write(v);
944 if (r < 0)
945 varlink_log_errno(v, r, "Write failed: %m");
946 if (r != 0)
947 goto finish;
948
949 r = varlink_dispatch_reply(v);
950 if (r < 0)
951 varlink_log_errno(v, r, "Reply dispatch failed: %m");
952 if (r != 0)
953 goto finish;
954
955 r = varlink_dispatch_method(v);
956 if (r < 0)
957 varlink_log_errno(v, r, "Method dispatch failed: %m");
958 if (r != 0)
959 goto finish;
960
961 r = varlink_parse_message(v);
962 if (r < 0)
963 varlink_log_errno(v, r, "Message parsing failed: %m");
964 if (r != 0)
965 goto finish;
966
967 r = varlink_read(v);
968 if (r < 0)
969 varlink_log_errno(v, r, "Read failed: %m");
970 if (r != 0)
971 goto finish;
972
973 r = varlink_test_disconnect(v);
974 assert(r >= 0);
975 if (r != 0)
976 goto finish;
977
978 r = varlink_dispatch_disconnect(v);
979 assert(r >= 0);
980 if (r != 0)
981 goto finish;
982
983 r = varlink_test_timeout(v);
984 assert(r >= 0);
985 if (r != 0)
986 goto finish;
987
988 r = varlink_dispatch_timeout(v);
989 assert(r >= 0);
990 if (r != 0)
991 goto finish;
992
993 finish:
994 if (r >= 0 && v->defer_event_source) {
995 int q;
996
997 /* If we did some processing, make sure we are called again soon */
998 q = sd_event_source_set_enabled(v->defer_event_source, r > 0 ? SD_EVENT_ON : SD_EVENT_OFF);
999 if (q < 0)
1000 r = varlink_log_errno(v, q, "Failed to enable deferred event source: %m");
1001 }
1002
1003 if (r < 0) {
1004 if (VARLINK_STATE_IS_ALIVE(v->state))
1005 /* Initiate disconnection */
1006 varlink_set_state(v, VARLINK_PENDING_DISCONNECT);
1007 else
1008 /* We failed while disconnecting, in that case close right away */
1009 varlink_close(v);
1010 }
1011
1012 varlink_unref(v);
1013 return r;
1014 }
1015
1016 static void handle_revents(Varlink *v, int revents) {
1017 assert(v);
1018
1019 if (v->connecting) {
1020 /* If we have seen POLLOUT or POLLHUP on a socket we are asynchronously waiting a connect()
1021 * to complete on, we know we are ready. We don't read the connection error here though,
1022 * we'll get the error on the next read() or write(). */
1023 if ((revents & (POLLOUT|POLLHUP)) == 0)
1024 return;
1025
1026 varlink_log(v, "Anynchronous connection completed.");
1027 v->connecting = false;
1028 } else {
1029 /* Note that we don't care much about POLLIN/POLLOUT here, we'll just try reading and writing
1030 * what we can. However, we do care about POLLHUP to detect connection termination even if we
1031 * momentarily don't want to read nor write anything. */
1032
1033 if (!FLAGS_SET(revents, POLLHUP))
1034 return;
1035
1036 varlink_log(v, "Got POLLHUP from socket.");
1037 v->got_pollhup = true;
1038 }
1039 }
1040
1041 int varlink_wait(Varlink *v, usec_t timeout) {
1042 int r, fd, events;
1043 usec_t t;
1044
1045 assert_return(v, -EINVAL);
1046
1047 if (v->state == VARLINK_DISCONNECTED)
1048 return varlink_log_errno(v, SYNTHETIC_ERRNO(ENOTCONN), "Not connected.");
1049
1050 r = varlink_get_timeout(v, &t);
1051 if (r < 0)
1052 return r;
1053 if (t != USEC_INFINITY) {
1054 usec_t n;
1055
1056 n = now(CLOCK_MONOTONIC);
1057 if (t < n)
1058 t = 0;
1059 else
1060 t = usec_sub_unsigned(t, n);
1061 }
1062
1063 if (timeout != USEC_INFINITY &&
1064 (t == USEC_INFINITY || timeout < t))
1065 t = timeout;
1066
1067 fd = varlink_get_fd(v);
1068 if (fd < 0)
1069 return fd;
1070
1071 events = varlink_get_events(v);
1072 if (events < 0)
1073 return events;
1074
1075 r = fd_wait_for_event(fd, events, t);
1076 if (r <= 0)
1077 return r;
1078
1079 handle_revents(v, r);
1080 return 1;
1081 }
1082
1083 int varlink_get_fd(Varlink *v) {
1084
1085 assert_return(v, -EINVAL);
1086
1087 if (v->state == VARLINK_DISCONNECTED)
1088 return varlink_log_errno(v, SYNTHETIC_ERRNO(ENOTCONN), "Not connected.");
1089 if (v->fd < 0)
1090 return varlink_log_errno(v, SYNTHETIC_ERRNO(EBADF), "No valid fd.");
1091
1092 return v->fd;
1093 }
1094
1095 int varlink_get_events(Varlink *v) {
1096 int ret = 0;
1097
1098 assert_return(v, -EINVAL);
1099
1100 if (v->state == VARLINK_DISCONNECTED)
1101 return varlink_log_errno(v, SYNTHETIC_ERRNO(ENOTCONN), "Not connected.");
1102
1103 if (v->connecting) /* When processing an asynchronous connect(), we only wait for EPOLLOUT, which
1104 * tells us that the connection is now complete. Before that we should neither
1105 * write() or read() from the fd. */
1106 return EPOLLOUT;
1107
1108 if (!v->read_disconnected &&
1109 IN_SET(v->state, VARLINK_AWAITING_REPLY, VARLINK_AWAITING_REPLY_MORE, VARLINK_CALLING, VARLINK_IDLE_SERVER) &&
1110 !v->current &&
1111 v->input_buffer_unscanned <= 0)
1112 ret |= EPOLLIN;
1113
1114 if (!v->write_disconnected &&
1115 v->output_buffer_size > 0)
1116 ret |= EPOLLOUT;
1117
1118 return ret;
1119 }
1120
1121 int varlink_get_timeout(Varlink *v, usec_t *ret) {
1122 assert_return(v, -EINVAL);
1123
1124 if (v->state == VARLINK_DISCONNECTED)
1125 return varlink_log_errno(v, SYNTHETIC_ERRNO(ENOTCONN), "Not connected.");
1126
1127 if (IN_SET(v->state, VARLINK_AWAITING_REPLY, VARLINK_AWAITING_REPLY_MORE, VARLINK_CALLING) &&
1128 v->timeout != USEC_INFINITY) {
1129 if (ret)
1130 *ret = usec_add(v->timestamp, v->timeout);
1131 return 1;
1132 } else {
1133 if (ret)
1134 *ret = USEC_INFINITY;
1135 return 0;
1136 }
1137 }
1138
1139 int varlink_flush(Varlink *v) {
1140 int ret = 0, r;
1141
1142 assert_return(v, -EINVAL);
1143
1144 if (v->state == VARLINK_DISCONNECTED)
1145 return varlink_log_errno(v, SYNTHETIC_ERRNO(ENOTCONN), "Not connected.");
1146
1147 for (;;) {
1148 if (v->output_buffer_size == 0)
1149 break;
1150 if (v->write_disconnected)
1151 return -ECONNRESET;
1152
1153 r = varlink_write(v);
1154 if (r < 0)
1155 return r;
1156 if (r > 0) {
1157 ret = 1;
1158 continue;
1159 }
1160
1161 r = fd_wait_for_event(v->fd, POLLOUT, USEC_INFINITY);
1162 if (r < 0)
1163 return varlink_log_errno(v, r, "Poll failed on fd: %m");
1164
1165 assert(r != 0);
1166
1167 handle_revents(v, r);
1168 }
1169
1170 return ret;
1171 }
1172
1173 static void varlink_detach_server(Varlink *v) {
1174 VarlinkServer *saved_server;
1175 assert(v);
1176
1177 if (!v->server)
1178 return;
1179
1180 if (v->server->by_uid &&
1181 v->ucred_acquired &&
1182 uid_is_valid(v->ucred.uid)) {
1183 unsigned c;
1184
1185 c = PTR_TO_UINT(hashmap_get(v->server->by_uid, UID_TO_PTR(v->ucred.uid)));
1186 assert(c > 0);
1187
1188 if (c == 1)
1189 (void) hashmap_remove(v->server->by_uid, UID_TO_PTR(v->ucred.uid));
1190 else
1191 (void) hashmap_replace(v->server->by_uid, UID_TO_PTR(v->ucred.uid), UINT_TO_PTR(c - 1));
1192 }
1193
1194 assert(v->server->n_connections > 0);
1195 v->server->n_connections--;
1196
1197 /* If this is a connection associated to a server, then let's disconnect the server and the
1198 * connection from each other. This drops the dangling reference that connect_callback() set up. But
1199 * before we release the references, let's call the disconnection callback if it is defined. */
1200
1201 saved_server = TAKE_PTR(v->server);
1202
1203 if (saved_server->disconnect_callback)
1204 saved_server->disconnect_callback(saved_server, v, saved_server->userdata);
1205
1206 varlink_server_unref(saved_server);
1207 varlink_unref(v);
1208 }
1209
1210 int varlink_close(Varlink *v) {
1211 assert_return(v, -EINVAL);
1212
1213 if (v->state == VARLINK_DISCONNECTED)
1214 return 0;
1215
1216 varlink_set_state(v, VARLINK_DISCONNECTED);
1217
1218 /* Let's take a reference first, since varlink_detach_server() might drop the final (dangling) ref
1219 * which would destroy us before we can call varlink_clear() */
1220 varlink_ref(v);
1221 varlink_detach_server(v);
1222 varlink_clear(v);
1223 varlink_unref(v);
1224
1225 return 1;
1226 }
1227
1228 Varlink* varlink_close_unref(Varlink *v) {
1229 if (!v)
1230 return NULL;
1231
1232 (void) varlink_close(v);
1233 return varlink_unref(v);
1234 }
1235
1236 Varlink* varlink_flush_close_unref(Varlink *v) {
1237 if (!v)
1238 return NULL;
1239
1240 (void) varlink_flush(v);
1241 return varlink_close_unref(v);
1242 }
1243
1244 static int varlink_enqueue_json(Varlink *v, JsonVariant *m) {
1245 _cleanup_free_ char *text = NULL;
1246 int r;
1247
1248 assert(v);
1249 assert(m);
1250
1251 r = json_variant_format(m, 0, &text);
1252 if (r < 0)
1253 return r;
1254 assert(text[r] == '\0');
1255
1256 if (v->output_buffer_size + r + 1 > VARLINK_BUFFER_MAX)
1257 return -ENOBUFS;
1258
1259 varlink_log(v, "Sending message: %s", text);
1260
1261 if (v->output_buffer_size == 0) {
1262
1263 free_and_replace(v->output_buffer, text);
1264
1265 v->output_buffer_size = r + 1;
1266 v->output_buffer_index = 0;
1267
1268 } else if (v->output_buffer_index == 0) {
1269
1270 if (!GREEDY_REALLOC(v->output_buffer, v->output_buffer_size + r + 1))
1271 return -ENOMEM;
1272
1273 memcpy(v->output_buffer + v->output_buffer_size, text, r + 1);
1274 v->output_buffer_size += r + 1;
1275
1276 } else {
1277 char *n;
1278 const size_t new_size = v->output_buffer_size + r + 1;
1279
1280 n = new(char, new_size);
1281 if (!n)
1282 return -ENOMEM;
1283
1284 memcpy(mempcpy(n, v->output_buffer + v->output_buffer_index, v->output_buffer_size), text, r + 1);
1285
1286 free_and_replace(v->output_buffer, n);
1287 v->output_buffer_size = new_size;
1288 v->output_buffer_index = 0;
1289 }
1290
1291 return 0;
1292 }
1293
1294 int varlink_send(Varlink *v, const char *method, JsonVariant *parameters) {
1295 _cleanup_(json_variant_unrefp) JsonVariant *m = NULL;
1296 int r;
1297
1298 assert_return(v, -EINVAL);
1299 assert_return(method, -EINVAL);
1300
1301 if (v->state == VARLINK_DISCONNECTED)
1302 return varlink_log_errno(v, SYNTHETIC_ERRNO(ENOTCONN), "Not connected.");
1303
1304 /* We allow enqueuing multiple method calls at once! */
1305 if (!IN_SET(v->state, VARLINK_IDLE_CLIENT, VARLINK_AWAITING_REPLY))
1306 return varlink_log_errno(v, SYNTHETIC_ERRNO(EBUSY), "Connection busy.");
1307
1308 r = varlink_sanitize_parameters(&parameters);
1309 if (r < 0)
1310 return varlink_log_errno(v, r, "Failed to sanitize parameters: %m");
1311
1312 r = json_build(&m, JSON_BUILD_OBJECT(
1313 JSON_BUILD_PAIR("method", JSON_BUILD_STRING(method)),
1314 JSON_BUILD_PAIR("parameters", JSON_BUILD_VARIANT(parameters)),
1315 JSON_BUILD_PAIR("oneway", JSON_BUILD_BOOLEAN(true))));
1316 if (r < 0)
1317 return varlink_log_errno(v, r, "Failed to build json message: %m");
1318
1319 r = varlink_enqueue_json(v, m);
1320 if (r < 0)
1321 return varlink_log_errno(v, r, "Failed to enqueue json message: %m");
1322
1323 /* No state change here, this is one-way only after all */
1324 v->timestamp = now(CLOCK_MONOTONIC);
1325 return 0;
1326 }
1327
1328 int varlink_sendb(Varlink *v, const char *method, ...) {
1329 _cleanup_(json_variant_unrefp) JsonVariant *parameters = NULL;
1330 va_list ap;
1331 int r;
1332
1333 assert_return(v, -EINVAL);
1334
1335 va_start(ap, method);
1336 r = json_buildv(&parameters, ap);
1337 va_end(ap);
1338
1339 if (r < 0)
1340 return varlink_log_errno(v, r, "Failed to build json message: %m");
1341
1342 return varlink_send(v, method, parameters);
1343 }
1344
1345 int varlink_invoke(Varlink *v, const char *method, JsonVariant *parameters) {
1346 _cleanup_(json_variant_unrefp) JsonVariant *m = NULL;
1347 int r;
1348
1349 assert_return(v, -EINVAL);
1350 assert_return(method, -EINVAL);
1351
1352 if (v->state == VARLINK_DISCONNECTED)
1353 return varlink_log_errno(v, SYNTHETIC_ERRNO(ENOTCONN), "Not connected.");
1354
1355 /* We allow enqueuing multiple method calls at once! */
1356 if (!IN_SET(v->state, VARLINK_IDLE_CLIENT, VARLINK_AWAITING_REPLY))
1357 return varlink_log_errno(v, SYNTHETIC_ERRNO(EBUSY), "Connection busy.");
1358
1359 r = varlink_sanitize_parameters(&parameters);
1360 if (r < 0)
1361 return varlink_log_errno(v, r, "Failed to sanitize parameters: %m");
1362
1363 r = json_build(&m, JSON_BUILD_OBJECT(
1364 JSON_BUILD_PAIR("method", JSON_BUILD_STRING(method)),
1365 JSON_BUILD_PAIR("parameters", JSON_BUILD_VARIANT(parameters))));
1366 if (r < 0)
1367 return varlink_log_errno(v, r, "Failed to build json message: %m");
1368
1369 r = varlink_enqueue_json(v, m);
1370 if (r < 0)
1371 return varlink_log_errno(v, r, "Failed to enqueue json message: %m");
1372
1373 varlink_set_state(v, VARLINK_AWAITING_REPLY);
1374 v->n_pending++;
1375 v->timestamp = now(CLOCK_MONOTONIC);
1376
1377 return 0;
1378 }
1379
1380 int varlink_invokeb(Varlink *v, const char *method, ...) {
1381 _cleanup_(json_variant_unrefp) JsonVariant *parameters = NULL;
1382 va_list ap;
1383 int r;
1384
1385 assert_return(v, -EINVAL);
1386
1387 va_start(ap, method);
1388 r = json_buildv(&parameters, ap);
1389 va_end(ap);
1390
1391 if (r < 0)
1392 return varlink_log_errno(v, r, "Failed to build json message: %m");
1393
1394 return varlink_invoke(v, method, parameters);
1395 }
1396
1397 int varlink_observe(Varlink *v, const char *method, JsonVariant *parameters) {
1398 _cleanup_(json_variant_unrefp) JsonVariant *m = NULL;
1399 int r;
1400
1401 assert_return(v, -EINVAL);
1402 assert_return(method, -EINVAL);
1403
1404 if (v->state == VARLINK_DISCONNECTED)
1405 return varlink_log_errno(v, SYNTHETIC_ERRNO(ENOTCONN), "Not connected.");
1406
1407 /* Note that we don't allow enqueuing multiple method calls when we are in more/continues mode! We
1408 * thus insist on an idle client here. */
1409 if (v->state != VARLINK_IDLE_CLIENT)
1410 return varlink_log_errno(v, SYNTHETIC_ERRNO(EBUSY), "Connection busy.");
1411
1412 r = varlink_sanitize_parameters(&parameters);
1413 if (r < 0)
1414 return varlink_log_errno(v, r, "Failed to sanitize parameters: %m");
1415
1416 r = json_build(&m, JSON_BUILD_OBJECT(
1417 JSON_BUILD_PAIR("method", JSON_BUILD_STRING(method)),
1418 JSON_BUILD_PAIR("parameters", JSON_BUILD_VARIANT(parameters)),
1419 JSON_BUILD_PAIR("more", JSON_BUILD_BOOLEAN(true))));
1420 if (r < 0)
1421 return varlink_log_errno(v, r, "Failed to build json message: %m");
1422
1423 r = varlink_enqueue_json(v, m);
1424 if (r < 0)
1425 return varlink_log_errno(v, r, "Failed to enqueue json message: %m");
1426
1427 varlink_set_state(v, VARLINK_AWAITING_REPLY_MORE);
1428 v->n_pending++;
1429 v->timestamp = now(CLOCK_MONOTONIC);
1430
1431 return 0;
1432 }
1433
1434 int varlink_observeb(Varlink *v, const char *method, ...) {
1435 _cleanup_(json_variant_unrefp) JsonVariant *parameters = NULL;
1436 va_list ap;
1437 int r;
1438
1439 assert_return(v, -EINVAL);
1440
1441 va_start(ap, method);
1442 r = json_buildv(&parameters, ap);
1443 va_end(ap);
1444
1445 if (r < 0)
1446 return varlink_log_errno(v, r, "Failed to build json message: %m");
1447
1448 return varlink_observe(v, method, parameters);
1449 }
1450
1451 int varlink_call(
1452 Varlink *v,
1453 const char *method,
1454 JsonVariant *parameters,
1455 JsonVariant **ret_parameters,
1456 const char **ret_error_id,
1457 VarlinkReplyFlags *ret_flags) {
1458
1459 _cleanup_(json_variant_unrefp) JsonVariant *m = NULL;
1460 int r;
1461
1462 assert_return(v, -EINVAL);
1463 assert_return(method, -EINVAL);
1464
1465 if (v->state == VARLINK_DISCONNECTED)
1466 return varlink_log_errno(v, SYNTHETIC_ERRNO(ENOTCONN), "Not connected.");
1467 if (!IN_SET(v->state, VARLINK_IDLE_CLIENT))
1468 return varlink_log_errno(v, SYNTHETIC_ERRNO(EBUSY), "Connection busy.");
1469
1470 assert(v->n_pending == 0); /* n_pending can't be > 0 if we are in VARLINK_IDLE_CLIENT state */
1471
1472 r = varlink_sanitize_parameters(&parameters);
1473 if (r < 0)
1474 return varlink_log_errno(v, r, "Failed to sanitize parameters: %m");
1475
1476 r = json_build(&m, JSON_BUILD_OBJECT(
1477 JSON_BUILD_PAIR("method", JSON_BUILD_STRING(method)),
1478 JSON_BUILD_PAIR("parameters", JSON_BUILD_VARIANT(parameters))));
1479 if (r < 0)
1480 return varlink_log_errno(v, r, "Failed to build json message: %m");
1481
1482 r = varlink_enqueue_json(v, m);
1483 if (r < 0)
1484 return varlink_log_errno(v, r, "Failed to enqueue json message: %m");
1485
1486 varlink_set_state(v, VARLINK_CALLING);
1487 v->n_pending++;
1488 v->timestamp = now(CLOCK_MONOTONIC);
1489
1490 while (v->state == VARLINK_CALLING) {
1491
1492 r = varlink_process(v);
1493 if (r < 0)
1494 return r;
1495 if (r > 0)
1496 continue;
1497
1498 r = varlink_wait(v, USEC_INFINITY);
1499 if (r < 0)
1500 return r;
1501 }
1502
1503 switch (v->state) {
1504
1505 case VARLINK_CALLED:
1506 assert(v->current);
1507
1508 json_variant_unref(v->reply);
1509 v->reply = TAKE_PTR(v->current);
1510
1511 varlink_set_state(v, VARLINK_IDLE_CLIENT);
1512 assert(v->n_pending == 1);
1513 v->n_pending--;
1514
1515 if (ret_parameters)
1516 *ret_parameters = json_variant_by_key(v->reply, "parameters");
1517 if (ret_error_id)
1518 *ret_error_id = json_variant_string(json_variant_by_key(v->reply, "error"));
1519 if (ret_flags)
1520 *ret_flags = 0;
1521
1522 return 1;
1523
1524 case VARLINK_PENDING_DISCONNECT:
1525 case VARLINK_DISCONNECTED:
1526 return varlink_log_errno(v, SYNTHETIC_ERRNO(ECONNRESET), "Connection was closed.");
1527
1528 case VARLINK_PENDING_TIMEOUT:
1529 return varlink_log_errno(v, SYNTHETIC_ERRNO(ETIME), "Connection timed out.");
1530
1531 default:
1532 assert_not_reached();
1533 }
1534 }
1535
1536 int varlink_callb(
1537 Varlink *v,
1538 const char *method,
1539 JsonVariant **ret_parameters,
1540 const char **ret_error_id,
1541 VarlinkReplyFlags *ret_flags, ...) {
1542
1543 _cleanup_(json_variant_unrefp) JsonVariant *parameters = NULL;
1544 va_list ap;
1545 int r;
1546
1547 assert_return(v, -EINVAL);
1548
1549 va_start(ap, ret_flags);
1550 r = json_buildv(&parameters, ap);
1551 va_end(ap);
1552
1553 if (r < 0)
1554 return varlink_log_errno(v, r, "Failed to build json message: %m");
1555
1556 return varlink_call(v, method, parameters, ret_parameters, ret_error_id, ret_flags);
1557 }
1558
1559 int varlink_reply(Varlink *v, JsonVariant *parameters) {
1560 _cleanup_(json_variant_unrefp) JsonVariant *m = NULL;
1561 int r;
1562
1563 assert_return(v, -EINVAL);
1564
1565 if (v->state == VARLINK_DISCONNECTED)
1566 return -ENOTCONN;
1567 if (!IN_SET(v->state,
1568 VARLINK_PROCESSING_METHOD, VARLINK_PROCESSING_METHOD_MORE,
1569 VARLINK_PENDING_METHOD, VARLINK_PENDING_METHOD_MORE))
1570 return -EBUSY;
1571
1572 r = varlink_sanitize_parameters(&parameters);
1573 if (r < 0)
1574 return varlink_log_errno(v, r, "Failed to sanitize parameters: %m");
1575
1576 r = json_build(&m, JSON_BUILD_OBJECT(JSON_BUILD_PAIR("parameters", JSON_BUILD_VARIANT(parameters))));
1577 if (r < 0)
1578 return varlink_log_errno(v, r, "Failed to build json message: %m");
1579
1580 r = varlink_enqueue_json(v, m);
1581 if (r < 0)
1582 return varlink_log_errno(v, r, "Failed to enqueue json message: %m");
1583
1584 if (IN_SET(v->state, VARLINK_PENDING_METHOD, VARLINK_PENDING_METHOD_MORE)) {
1585 /* We just replied to a method call that was let hanging for a while (i.e. we were outside of
1586 * the varlink_dispatch_method() stack frame), which means with this reply we are ready to
1587 * process further messages. */
1588 v->current = json_variant_unref(v->current);
1589 varlink_set_state(v, VARLINK_IDLE_SERVER);
1590 } else
1591 /* We replied to a method call from within the varlink_dispatch_method() stack frame), which
1592 * means we should it handle the rest of the state engine. */
1593 varlink_set_state(v, VARLINK_PROCESSED_METHOD);
1594
1595 return 1;
1596 }
1597
1598 int varlink_replyb(Varlink *v, ...) {
1599 _cleanup_(json_variant_unrefp) JsonVariant *parameters = NULL;
1600 va_list ap;
1601 int r;
1602
1603 assert_return(v, -EINVAL);
1604
1605 va_start(ap, v);
1606 r = json_buildv(&parameters, ap);
1607 va_end(ap);
1608
1609 if (r < 0)
1610 return r;
1611
1612 return varlink_reply(v, parameters);
1613 }
1614
1615 int varlink_error(Varlink *v, const char *error_id, JsonVariant *parameters) {
1616 _cleanup_(json_variant_unrefp) JsonVariant *m = NULL;
1617 int r;
1618
1619 assert_return(v, -EINVAL);
1620 assert_return(error_id, -EINVAL);
1621
1622 if (v->state == VARLINK_DISCONNECTED)
1623 return varlink_log_errno(v, SYNTHETIC_ERRNO(ENOTCONN), "Not connected.");
1624 if (!IN_SET(v->state,
1625 VARLINK_PROCESSING_METHOD, VARLINK_PROCESSING_METHOD_MORE,
1626 VARLINK_PENDING_METHOD, VARLINK_PENDING_METHOD_MORE))
1627 return varlink_log_errno(v, SYNTHETIC_ERRNO(EBUSY), "Connection busy.");
1628
1629 r = varlink_sanitize_parameters(&parameters);
1630 if (r < 0)
1631 return varlink_log_errno(v, r, "Failed to sanitize parameters: %m");
1632
1633 r = json_build(&m, JSON_BUILD_OBJECT(
1634 JSON_BUILD_PAIR("error", JSON_BUILD_STRING(error_id)),
1635 JSON_BUILD_PAIR("parameters", JSON_BUILD_VARIANT(parameters))));
1636 if (r < 0)
1637 return varlink_log_errno(v, r, "Failed to build json message: %m");
1638
1639 r = varlink_enqueue_json(v, m);
1640 if (r < 0)
1641 return varlink_log_errno(v, r, "Failed to enqueue json message: %m");
1642
1643 if (IN_SET(v->state, VARLINK_PENDING_METHOD, VARLINK_PENDING_METHOD_MORE)) {
1644 v->current = json_variant_unref(v->current);
1645 varlink_set_state(v, VARLINK_IDLE_SERVER);
1646 } else
1647 varlink_set_state(v, VARLINK_PROCESSED_METHOD);
1648
1649 return 1;
1650 }
1651
1652 int varlink_errorb(Varlink *v, const char *error_id, ...) {
1653 _cleanup_(json_variant_unrefp) JsonVariant *parameters = NULL;
1654 va_list ap;
1655 int r;
1656
1657 assert_return(v, -EINVAL);
1658 assert_return(error_id, -EINVAL);
1659
1660 va_start(ap, error_id);
1661 r = json_buildv(&parameters, ap);
1662 va_end(ap);
1663
1664 if (r < 0)
1665 return varlink_log_errno(v, r, "Failed to build json message: %m");
1666
1667 return varlink_error(v, error_id, parameters);
1668 }
1669
1670 int varlink_error_invalid_parameter(Varlink *v, JsonVariant *parameters) {
1671 int r;
1672
1673 assert_return(v, -EINVAL);
1674 assert_return(parameters, -EINVAL);
1675
1676 /* We expect to be called in one of two ways: the 'parameters' argument is a string variant in which
1677 * case it is the parameter key name that is invalid. Or the 'parameters' argument is an object
1678 * variant in which case we'll pull out the first key. The latter mode is useful in functions that
1679 * don't expect any arguments. */
1680
1681 /* varlink_error(...) expects a json object as the third parameter. Passing a string variant causes
1682 * parameter sanitization to fail, and it returns -EINVAL. */
1683
1684 if (json_variant_is_string(parameters)) {
1685 _cleanup_(json_variant_unrefp) JsonVariant *parameters_obj = NULL;
1686
1687 r = json_build(&parameters_obj,
1688 JSON_BUILD_OBJECT(
1689 JSON_BUILD_PAIR("parameter", JSON_BUILD_VARIANT(parameters))));
1690 if (r < 0)
1691 return r;
1692
1693 return varlink_error(v, VARLINK_ERROR_INVALID_PARAMETER, parameters_obj);
1694 }
1695
1696 if (json_variant_is_object(parameters) &&
1697 json_variant_elements(parameters) > 0) {
1698 _cleanup_(json_variant_unrefp) JsonVariant *parameters_obj = NULL;
1699
1700 r = json_build(&parameters_obj,
1701 JSON_BUILD_OBJECT(
1702 JSON_BUILD_PAIR("parameter", JSON_BUILD_VARIANT(json_variant_by_index(parameters, 0)))));
1703 if (r < 0)
1704 return r;
1705
1706 return varlink_error(v, VARLINK_ERROR_INVALID_PARAMETER, parameters_obj);
1707 }
1708
1709 return -EINVAL;
1710 }
1711
1712 int varlink_error_errno(Varlink *v, int error) {
1713 return varlink_errorb(
1714 v,
1715 VARLINK_ERROR_SYSTEM,
1716 JSON_BUILD_OBJECT(JSON_BUILD_PAIR("errno", JSON_BUILD_INTEGER(abs(error)))));
1717 }
1718
1719 int varlink_notify(Varlink *v, JsonVariant *parameters) {
1720 _cleanup_(json_variant_unrefp) JsonVariant *m = NULL;
1721 int r;
1722
1723 assert_return(v, -EINVAL);
1724
1725 if (v->state == VARLINK_DISCONNECTED)
1726 return varlink_log_errno(v, SYNTHETIC_ERRNO(ENOTCONN), "Not connected.");
1727 if (!IN_SET(v->state, VARLINK_PROCESSING_METHOD_MORE, VARLINK_PENDING_METHOD_MORE))
1728 return varlink_log_errno(v, SYNTHETIC_ERRNO(EBUSY), "Connection busy.");
1729
1730 r = varlink_sanitize_parameters(&parameters);
1731 if (r < 0)
1732 return varlink_log_errno(v, r, "Failed to sanitize parameters: %m");
1733
1734 r = json_build(&m, JSON_BUILD_OBJECT(
1735 JSON_BUILD_PAIR("parameters", JSON_BUILD_VARIANT(parameters)),
1736 JSON_BUILD_PAIR("continues", JSON_BUILD_BOOLEAN(true))));
1737 if (r < 0)
1738 return varlink_log_errno(v, r, "Failed to build json message: %m");
1739
1740 r = varlink_enqueue_json(v, m);
1741 if (r < 0)
1742 return varlink_log_errno(v, r, "Failed to enqueue json message: %m");
1743
1744 /* No state change, as more is coming */
1745 return 1;
1746 }
1747
1748 int varlink_notifyb(Varlink *v, ...) {
1749 _cleanup_(json_variant_unrefp) JsonVariant *parameters = NULL;
1750 va_list ap;
1751 int r;
1752
1753 assert_return(v, -EINVAL);
1754
1755 va_start(ap, v);
1756 r = json_buildv(&parameters, ap);
1757 va_end(ap);
1758
1759 if (r < 0)
1760 return varlink_log_errno(v, r, "Failed to build json message: %m");
1761
1762 return varlink_notify(v, parameters);
1763 }
1764
1765 int varlink_bind_reply(Varlink *v, VarlinkReply callback) {
1766 assert_return(v, -EINVAL);
1767
1768 if (callback && v->reply_callback && callback != v->reply_callback)
1769 return varlink_log_errno(v, SYNTHETIC_ERRNO(EBUSY), "A different callback was already set.");
1770
1771 v->reply_callback = callback;
1772
1773 return 0;
1774 }
1775
1776 void* varlink_set_userdata(Varlink *v, void *userdata) {
1777 void *old;
1778
1779 assert_return(v, NULL);
1780
1781 old = v->userdata;
1782 v->userdata = userdata;
1783
1784 return old;
1785 }
1786
1787 void* varlink_get_userdata(Varlink *v) {
1788 assert_return(v, NULL);
1789
1790 return v->userdata;
1791 }
1792
1793 static int varlink_acquire_ucred(Varlink *v) {
1794 int r;
1795
1796 assert(v);
1797
1798 if (v->ucred_acquired)
1799 return 0;
1800
1801 r = getpeercred(v->fd, &v->ucred);
1802 if (r < 0)
1803 return r;
1804
1805 v->ucred_acquired = true;
1806 return 0;
1807 }
1808
1809 int varlink_get_peer_uid(Varlink *v, uid_t *ret) {
1810 int r;
1811
1812 assert_return(v, -EINVAL);
1813 assert_return(ret, -EINVAL);
1814
1815 r = varlink_acquire_ucred(v);
1816 if (r < 0)
1817 return varlink_log_errno(v, r, "Failed to acquire credentials: %m");
1818
1819 if (!uid_is_valid(v->ucred.uid))
1820 return varlink_log_errno(v, SYNTHETIC_ERRNO(ENODATA), "Peer uid is invalid.");
1821
1822 *ret = v->ucred.uid;
1823 return 0;
1824 }
1825
1826 int varlink_get_peer_pid(Varlink *v, pid_t *ret) {
1827 int r;
1828
1829 assert_return(v, -EINVAL);
1830 assert_return(ret, -EINVAL);
1831
1832 r = varlink_acquire_ucred(v);
1833 if (r < 0)
1834 return varlink_log_errno(v, r, "Failed to acquire credentials: %m");
1835
1836 if (!pid_is_valid(v->ucred.pid))
1837 return varlink_log_errno(v, SYNTHETIC_ERRNO(ENODATA), "Peer uid is invalid.");
1838
1839 *ret = v->ucred.pid;
1840 return 0;
1841 }
1842
1843 int varlink_set_relative_timeout(Varlink *v, usec_t timeout) {
1844 assert_return(v, -EINVAL);
1845 assert_return(timeout > 0, -EINVAL);
1846
1847 v->timeout = timeout;
1848 return 0;
1849 }
1850
1851 VarlinkServer *varlink_get_server(Varlink *v) {
1852 assert_return(v, NULL);
1853
1854 return v->server;
1855 }
1856
1857 int varlink_set_description(Varlink *v, const char *description) {
1858 assert_return(v, -EINVAL);
1859
1860 return free_and_strdup(&v->description, description);
1861 }
1862
1863 static int io_callback(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
1864 Varlink *v = ASSERT_PTR(userdata);
1865
1866 assert(s);
1867
1868 handle_revents(v, revents);
1869 (void) varlink_process(v);
1870
1871 return 1;
1872 }
1873
1874 static int time_callback(sd_event_source *s, uint64_t usec, void *userdata) {
1875 Varlink *v = ASSERT_PTR(userdata);
1876
1877 assert(s);
1878
1879 (void) varlink_process(v);
1880 return 1;
1881 }
1882
1883 static int defer_callback(sd_event_source *s, void *userdata) {
1884 Varlink *v = ASSERT_PTR(userdata);
1885
1886 assert(s);
1887
1888 (void) varlink_process(v);
1889 return 1;
1890 }
1891
1892 static int prepare_callback(sd_event_source *s, void *userdata) {
1893 Varlink *v = ASSERT_PTR(userdata);
1894 int r, e;
1895 usec_t until;
1896 bool have_timeout;
1897
1898 assert(s);
1899
1900 e = varlink_get_events(v);
1901 if (e < 0)
1902 return e;
1903
1904 r = sd_event_source_set_io_events(v->io_event_source, e);
1905 if (r < 0)
1906 return varlink_log_errno(v, r, "Failed to set source events: %m");
1907
1908 r = varlink_get_timeout(v, &until);
1909 if (r < 0)
1910 return r;
1911 have_timeout = r > 0;
1912
1913 if (have_timeout) {
1914 r = sd_event_source_set_time(v->time_event_source, until);
1915 if (r < 0)
1916 return varlink_log_errno(v, r, "Failed to set source time: %m");
1917 }
1918
1919 r = sd_event_source_set_enabled(v->time_event_source, have_timeout ? SD_EVENT_ON : SD_EVENT_OFF);
1920 if (r < 0)
1921 return varlink_log_errno(v, r, "Failed to enable event source: %m");
1922
1923 return 1;
1924 }
1925
1926 static int quit_callback(sd_event_source *event, void *userdata) {
1927 Varlink *v = ASSERT_PTR(userdata);
1928
1929 assert(event);
1930
1931 varlink_flush(v);
1932 varlink_close(v);
1933
1934 return 1;
1935 }
1936
1937 int varlink_attach_event(Varlink *v, sd_event *e, int64_t priority) {
1938 int r;
1939
1940 assert_return(v, -EINVAL);
1941 assert_return(!v->event, -EBUSY);
1942
1943 if (e)
1944 v->event = sd_event_ref(e);
1945 else {
1946 r = sd_event_default(&v->event);
1947 if (r < 0)
1948 return varlink_log_errno(v, r, "Failed to create event source: %m");
1949 }
1950
1951 r = sd_event_add_time(v->event, &v->time_event_source, CLOCK_MONOTONIC, 0, 0, time_callback, v);
1952 if (r < 0)
1953 goto fail;
1954
1955 r = sd_event_source_set_priority(v->time_event_source, priority);
1956 if (r < 0)
1957 goto fail;
1958
1959 (void) sd_event_source_set_description(v->time_event_source, "varlink-time");
1960
1961 r = sd_event_add_exit(v->event, &v->quit_event_source, quit_callback, v);
1962 if (r < 0)
1963 goto fail;
1964
1965 r = sd_event_source_set_priority(v->quit_event_source, priority);
1966 if (r < 0)
1967 goto fail;
1968
1969 (void) sd_event_source_set_description(v->quit_event_source, "varlink-quit");
1970
1971 r = sd_event_add_io(v->event, &v->io_event_source, v->fd, 0, io_callback, v);
1972 if (r < 0)
1973 goto fail;
1974
1975 r = sd_event_source_set_prepare(v->io_event_source, prepare_callback);
1976 if (r < 0)
1977 goto fail;
1978
1979 r = sd_event_source_set_priority(v->io_event_source, priority);
1980 if (r < 0)
1981 goto fail;
1982
1983 (void) sd_event_source_set_description(v->io_event_source, "varlink-io");
1984
1985 r = sd_event_add_defer(v->event, &v->defer_event_source, defer_callback, v);
1986 if (r < 0)
1987 goto fail;
1988
1989 r = sd_event_source_set_priority(v->defer_event_source, priority);
1990 if (r < 0)
1991 goto fail;
1992
1993 (void) sd_event_source_set_description(v->defer_event_source, "varlink-defer");
1994
1995 return 0;
1996
1997 fail:
1998 varlink_log_errno(v, r, "Failed to setup event source: %m");
1999 varlink_detach_event(v);
2000 return r;
2001 }
2002
2003 void varlink_detach_event(Varlink *v) {
2004 if (!v)
2005 return;
2006
2007 varlink_detach_event_sources(v);
2008
2009 v->event = sd_event_unref(v->event);
2010 }
2011
2012 sd_event *varlink_get_event(Varlink *v) {
2013 assert_return(v, NULL);
2014
2015 return v->event;
2016 }
2017
2018 int varlink_server_new(VarlinkServer **ret, VarlinkServerFlags flags) {
2019 VarlinkServer *s;
2020
2021 assert_return(ret, -EINVAL);
2022 assert_return((flags & ~_VARLINK_SERVER_FLAGS_ALL) == 0, -EINVAL);
2023
2024 s = new(VarlinkServer, 1);
2025 if (!s)
2026 return log_oom_debug();
2027
2028 *s = (VarlinkServer) {
2029 .n_ref = 1,
2030 .flags = flags,
2031 .connections_max = varlink_server_connections_max(NULL),
2032 .connections_per_uid_max = varlink_server_connections_per_uid_max(NULL),
2033 };
2034
2035 *ret = s;
2036 return 0;
2037 }
2038
2039 static VarlinkServer* varlink_server_destroy(VarlinkServer *s) {
2040 char *m;
2041
2042 if (!s)
2043 return NULL;
2044
2045 varlink_server_shutdown(s);
2046
2047 while ((m = hashmap_steal_first_key(s->methods)))
2048 free(m);
2049
2050 hashmap_free(s->methods);
2051 hashmap_free(s->by_uid);
2052
2053 sd_event_unref(s->event);
2054
2055 free(s->description);
2056
2057 return mfree(s);
2058 }
2059
2060 DEFINE_TRIVIAL_REF_UNREF_FUNC(VarlinkServer, varlink_server, varlink_server_destroy);
2061
2062 static int validate_connection(VarlinkServer *server, const struct ucred *ucred) {
2063 int allowed = -1;
2064
2065 assert(server);
2066 assert(ucred);
2067
2068 if (FLAGS_SET(server->flags, VARLINK_SERVER_ROOT_ONLY))
2069 allowed = ucred->uid == 0;
2070
2071 if (FLAGS_SET(server->flags, VARLINK_SERVER_MYSELF_ONLY))
2072 allowed = allowed > 0 || ucred->uid == getuid();
2073
2074 if (allowed == 0) { /* Allow access when it is explicitly allowed or when neither
2075 * VARLINK_SERVER_ROOT_ONLY nor VARLINK_SERVER_MYSELF_ONLY are specified. */
2076 varlink_server_log(server, "Unprivileged client attempted connection, refusing.");
2077 return 0;
2078 }
2079
2080 if (server->n_connections >= server->connections_max) {
2081 varlink_server_log(server, "Connection limit of %u reached, refusing.", server->connections_max);
2082 return 0;
2083 }
2084
2085 if (FLAGS_SET(server->flags, VARLINK_SERVER_ACCOUNT_UID)) {
2086 unsigned c;
2087
2088 if (!uid_is_valid(ucred->uid)) {
2089 varlink_server_log(server, "Client with invalid UID attempted connection, refusing.");
2090 return 0;
2091 }
2092
2093 c = PTR_TO_UINT(hashmap_get(server->by_uid, UID_TO_PTR(ucred->uid)));
2094 if (c >= server->connections_per_uid_max) {
2095 varlink_server_log(server, "Per-UID connection limit of %u reached, refusing.",
2096 server->connections_per_uid_max);
2097 return 0;
2098 }
2099 }
2100
2101 return 1;
2102 }
2103
2104 static int count_connection(VarlinkServer *server, const struct ucred *ucred) {
2105 unsigned c;
2106 int r;
2107
2108 assert(server);
2109 assert(ucred);
2110
2111 server->n_connections++;
2112
2113 if (FLAGS_SET(server->flags, VARLINK_SERVER_ACCOUNT_UID)) {
2114 r = hashmap_ensure_allocated(&server->by_uid, NULL);
2115 if (r < 0)
2116 return log_debug_errno(r, "Failed to allocate UID hash table: %m");
2117
2118 c = PTR_TO_UINT(hashmap_get(server->by_uid, UID_TO_PTR(ucred->uid)));
2119
2120 varlink_server_log(server, "Connections of user " UID_FMT ": %u (of %u max)",
2121 ucred->uid, c, server->connections_per_uid_max);
2122
2123 r = hashmap_replace(server->by_uid, UID_TO_PTR(ucred->uid), UINT_TO_PTR(c + 1));
2124 if (r < 0)
2125 return log_debug_errno(r, "Failed to increment counter in UID hash table: %m");
2126 }
2127
2128 return 0;
2129 }
2130
2131 int varlink_server_add_connection(VarlinkServer *server, int fd, Varlink **ret) {
2132 _cleanup_(varlink_unrefp) Varlink *v = NULL;
2133 struct ucred ucred = UCRED_INVALID;
2134 bool ucred_acquired;
2135 int r;
2136
2137 assert_return(server, -EINVAL);
2138 assert_return(fd >= 0, -EBADF);
2139
2140 if ((server->flags & (VARLINK_SERVER_ROOT_ONLY|VARLINK_SERVER_ACCOUNT_UID)) != 0) {
2141 r = getpeercred(fd, &ucred);
2142 if (r < 0)
2143 return varlink_server_log_errno(server, r, "Failed to acquire peer credentials of incoming socket, refusing: %m");
2144
2145 ucred_acquired = true;
2146
2147 r = validate_connection(server, &ucred);
2148 if (r < 0)
2149 return r;
2150 if (r == 0)
2151 return -EPERM;
2152 } else
2153 ucred_acquired = false;
2154
2155 r = varlink_new(&v);
2156 if (r < 0)
2157 return varlink_server_log_errno(server, r, "Failed to allocate connection object: %m");
2158
2159 r = count_connection(server, &ucred);
2160 if (r < 0)
2161 return r;
2162
2163 v->fd = fd;
2164 if (server->flags & VARLINK_SERVER_INHERIT_USERDATA)
2165 v->userdata = server->userdata;
2166
2167 if (ucred_acquired) {
2168 v->ucred = ucred;
2169 v->ucred_acquired = true;
2170 }
2171
2172 _cleanup_free_ char *desc = NULL;
2173 if (asprintf(&desc, "%s-%i", server->description ?: "varlink", v->fd) >= 0)
2174 v->description = TAKE_PTR(desc);
2175
2176 /* Link up the server and the connection, and take reference in both directions. Note that the
2177 * reference on the connection is left dangling. It will be dropped when the connection is closed,
2178 * which happens in varlink_close(), including in the event loop quit callback. */
2179 v->server = varlink_server_ref(server);
2180 varlink_ref(v);
2181
2182 varlink_set_state(v, VARLINK_IDLE_SERVER);
2183
2184 if (server->event) {
2185 r = varlink_attach_event(v, server->event, server->event_priority);
2186 if (r < 0) {
2187 varlink_log_errno(v, r, "Failed to attach new connection: %m");
2188 v->fd = -1; /* take the fd out of the connection again */
2189 varlink_close(v);
2190 return r;
2191 }
2192 }
2193
2194 if (ret)
2195 *ret = v;
2196
2197 return 0;
2198 }
2199
2200 static VarlinkServerSocket *varlink_server_socket_free(VarlinkServerSocket *ss) {
2201 if (!ss)
2202 return NULL;
2203
2204 free(ss->address);
2205 return mfree(ss);
2206 }
2207
2208 DEFINE_TRIVIAL_CLEANUP_FUNC(VarlinkServerSocket *, varlink_server_socket_free);
2209
2210 static int connect_callback(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
2211 VarlinkServerSocket *ss = ASSERT_PTR(userdata);
2212 _cleanup_close_ int cfd = -1;
2213 Varlink *v = NULL;
2214 int r;
2215
2216 assert(source);
2217
2218 varlink_server_log(ss->server, "New incoming connection.");
2219
2220 cfd = accept4(fd, NULL, NULL, SOCK_NONBLOCK|SOCK_CLOEXEC);
2221 if (cfd < 0) {
2222 if (ERRNO_IS_ACCEPT_AGAIN(errno))
2223 return 0;
2224
2225 return varlink_server_log_errno(ss->server, errno, "Failed to accept incoming socket: %m");
2226 }
2227
2228 r = varlink_server_add_connection(ss->server, cfd, &v);
2229 if (r < 0)
2230 return 0;
2231
2232 TAKE_FD(cfd);
2233
2234 if (ss->server->connect_callback) {
2235 r = ss->server->connect_callback(ss->server, v, ss->server->userdata);
2236 if (r < 0) {
2237 varlink_log_errno(v, r, "Connection callback returned error, disconnecting client: %m");
2238 varlink_close(v);
2239 return 0;
2240 }
2241 }
2242
2243 return 0;
2244 }
2245
2246 static int varlink_server_create_listen_fd_socket(VarlinkServer *s, int fd, VarlinkServerSocket **ret_ss) {
2247 _cleanup_(varlink_server_socket_freep) VarlinkServerSocket *ss = NULL;
2248 int r;
2249
2250 assert(s);
2251 assert(fd >= 0);
2252 assert(ret_ss);
2253
2254 r = fd_nonblock(fd, true);
2255 if (r < 0)
2256 return r;
2257
2258 ss = new(VarlinkServerSocket, 1);
2259 if (!ss)
2260 return log_oom_debug();
2261
2262 *ss = (VarlinkServerSocket) {
2263 .server = s,
2264 .fd = fd,
2265 };
2266
2267 if (s->event) {
2268 r = sd_event_add_io(s->event, &ss->event_source, fd, EPOLLIN, connect_callback, ss);
2269 if (r < 0)
2270 return r;
2271
2272 r = sd_event_source_set_priority(ss->event_source, s->event_priority);
2273 if (r < 0)
2274 return r;
2275 }
2276
2277 *ret_ss = TAKE_PTR(ss);
2278 return 0;
2279 }
2280
2281 int varlink_server_listen_fd(VarlinkServer *s, int fd) {
2282 _cleanup_(varlink_server_socket_freep) VarlinkServerSocket *ss = NULL;
2283 int r;
2284
2285 assert_return(s, -EINVAL);
2286 assert_return(fd >= 0, -EBADF);
2287
2288 r = varlink_server_create_listen_fd_socket(s, fd, &ss);
2289 if (r < 0)
2290 return r;
2291
2292 LIST_PREPEND(sockets, s->sockets, TAKE_PTR(ss));
2293 return 0;
2294 }
2295
2296 int varlink_server_listen_address(VarlinkServer *s, const char *address, mode_t m) {
2297 _cleanup_(varlink_server_socket_freep) VarlinkServerSocket *ss = NULL;
2298 union sockaddr_union sockaddr;
2299 socklen_t sockaddr_len;
2300 _cleanup_close_ int fd = -1;
2301 int r;
2302
2303 assert_return(s, -EINVAL);
2304 assert_return(address, -EINVAL);
2305 assert_return((m & ~0777) == 0, -EINVAL);
2306
2307 r = sockaddr_un_set_path(&sockaddr.un, address);
2308 if (r < 0)
2309 return r;
2310 sockaddr_len = r;
2311
2312 fd = socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
2313 if (fd < 0)
2314 return -errno;
2315
2316 fd = fd_move_above_stdio(fd);
2317
2318 (void) sockaddr_un_unlink(&sockaddr.un);
2319
2320 RUN_WITH_UMASK(~m & 0777) {
2321 r = mac_selinux_bind(fd, &sockaddr.sa, sockaddr_len);
2322 if (r < 0)
2323 return r;
2324 }
2325
2326 if (listen(fd, SOMAXCONN) < 0)
2327 return -errno;
2328
2329 r = varlink_server_create_listen_fd_socket(s, fd, &ss);
2330 if (r < 0)
2331 return r;
2332
2333 r = free_and_strdup(&ss->address, address);
2334 if (r < 0)
2335 return r;
2336
2337 LIST_PREPEND(sockets, s->sockets, TAKE_PTR(ss));
2338 TAKE_FD(fd);
2339 return 0;
2340 }
2341
2342 void* varlink_server_set_userdata(VarlinkServer *s, void *userdata) {
2343 void *ret;
2344
2345 assert_return(s, NULL);
2346
2347 ret = s->userdata;
2348 s->userdata = userdata;
2349
2350 return ret;
2351 }
2352
2353 void* varlink_server_get_userdata(VarlinkServer *s) {
2354 assert_return(s, NULL);
2355
2356 return s->userdata;
2357 }
2358
2359 static VarlinkServerSocket* varlink_server_socket_destroy(VarlinkServerSocket *ss) {
2360 if (!ss)
2361 return NULL;
2362
2363 if (ss->server)
2364 LIST_REMOVE(sockets, ss->server->sockets, ss);
2365
2366 sd_event_source_disable_unref(ss->event_source);
2367
2368 free(ss->address);
2369 safe_close(ss->fd);
2370
2371 return mfree(ss);
2372 }
2373
2374 int varlink_server_shutdown(VarlinkServer *s) {
2375 assert_return(s, -EINVAL);
2376
2377 while (s->sockets)
2378 varlink_server_socket_destroy(s->sockets);
2379
2380 return 0;
2381 }
2382
2383 static int varlink_server_add_socket_event_source(VarlinkServer *s, VarlinkServerSocket *ss, int64_t priority) {
2384 _cleanup_(sd_event_source_unrefp) sd_event_source *es = NULL;
2385
2386 int r;
2387
2388 assert(s);
2389 assert(s->event);
2390 assert(ss);
2391 assert(ss->fd >= 0);
2392 assert(!ss->event_source);
2393
2394 r = sd_event_add_io(s->event, &es, ss->fd, EPOLLIN, connect_callback, ss);
2395 if (r < 0)
2396 return r;
2397
2398 r = sd_event_source_set_priority(es, priority);
2399 if (r < 0)
2400 return r;
2401
2402 ss->event_source = TAKE_PTR(es);
2403 return 0;
2404 }
2405
2406 int varlink_server_attach_event(VarlinkServer *s, sd_event *e, int64_t priority) {
2407 int r;
2408
2409 assert_return(s, -EINVAL);
2410 assert_return(!s->event, -EBUSY);
2411
2412 if (e)
2413 s->event = sd_event_ref(e);
2414 else {
2415 r = sd_event_default(&s->event);
2416 if (r < 0)
2417 return r;
2418 }
2419
2420 LIST_FOREACH(sockets, ss, s->sockets) {
2421 r = varlink_server_add_socket_event_source(s, ss, priority);
2422 if (r < 0)
2423 goto fail;
2424 }
2425
2426 s->event_priority = priority;
2427 return 0;
2428
2429 fail:
2430 varlink_server_detach_event(s);
2431 return r;
2432 }
2433
2434 int varlink_server_detach_event(VarlinkServer *s) {
2435 assert_return(s, -EINVAL);
2436
2437 LIST_FOREACH(sockets, ss, s->sockets)
2438 ss->event_source = sd_event_source_disable_unref(ss->event_source);
2439
2440 sd_event_unref(s->event);
2441 return 0;
2442 }
2443
2444 sd_event *varlink_server_get_event(VarlinkServer *s) {
2445 assert_return(s, NULL);
2446
2447 return s->event;
2448 }
2449
2450 int varlink_server_bind_method(VarlinkServer *s, const char *method, VarlinkMethod callback) {
2451 _cleanup_free_ char *m = NULL;
2452 int r;
2453
2454 assert_return(s, -EINVAL);
2455 assert_return(method, -EINVAL);
2456 assert_return(callback, -EINVAL);
2457
2458 if (startswith(method, "org.varlink.service."))
2459 return log_debug_errno(SYNTHETIC_ERRNO(EEXIST), "Cannot bind server to '%s'.", method);
2460
2461 m = strdup(method);
2462 if (!m)
2463 return log_oom_debug();
2464
2465 r = hashmap_ensure_put(&s->methods, &string_hash_ops, m, callback);
2466 if (r == -ENOMEM)
2467 return log_oom_debug();
2468 if (r < 0)
2469 return log_debug_errno(r, "Failed to register callback: %m");
2470 if (r > 0)
2471 TAKE_PTR(m);
2472
2473 return 0;
2474 }
2475
2476 int varlink_server_bind_method_many_internal(VarlinkServer *s, ...) {
2477 va_list ap;
2478 int r = 0;
2479
2480 assert_return(s, -EINVAL);
2481
2482 va_start(ap, s);
2483 for (;;) {
2484 VarlinkMethod callback;
2485 const char *method;
2486
2487 method = va_arg(ap, const char *);
2488 if (!method)
2489 break;
2490
2491 callback = va_arg(ap, VarlinkMethod);
2492
2493 r = varlink_server_bind_method(s, method, callback);
2494 if (r < 0)
2495 break;
2496 }
2497 va_end(ap);
2498
2499 return r;
2500 }
2501
2502 int varlink_server_bind_connect(VarlinkServer *s, VarlinkConnect callback) {
2503 assert_return(s, -EINVAL);
2504
2505 if (callback && s->connect_callback && callback != s->connect_callback)
2506 return log_debug_errno(SYNTHETIC_ERRNO(EBUSY), "A different callback was already set.");
2507
2508 s->connect_callback = callback;
2509 return 0;
2510 }
2511
2512 int varlink_server_bind_disconnect(VarlinkServer *s, VarlinkDisconnect callback) {
2513 assert_return(s, -EINVAL);
2514
2515 if (callback && s->disconnect_callback && callback != s->disconnect_callback)
2516 return log_debug_errno(SYNTHETIC_ERRNO(EBUSY), "A different callback was already set.");
2517
2518 s->disconnect_callback = callback;
2519 return 0;
2520 }
2521
2522 unsigned varlink_server_connections_max(VarlinkServer *s) {
2523 int dts;
2524
2525 /* If a server is specified, return the setting for that server, otherwise the default value */
2526 if (s)
2527 return s->connections_max;
2528
2529 dts = getdtablesize();
2530 assert_se(dts > 0);
2531
2532 /* Make sure we never use up more than ¾th of RLIMIT_NOFILE for IPC */
2533 if (VARLINK_DEFAULT_CONNECTIONS_MAX > (unsigned) dts / 4 * 3)
2534 return dts / 4 * 3;
2535
2536 return VARLINK_DEFAULT_CONNECTIONS_MAX;
2537 }
2538
2539 unsigned varlink_server_connections_per_uid_max(VarlinkServer *s) {
2540 unsigned m;
2541
2542 if (s)
2543 return s->connections_per_uid_max;
2544
2545 /* Make sure to never use up more than ¾th of available connections for a single user */
2546 m = varlink_server_connections_max(NULL);
2547 if (VARLINK_DEFAULT_CONNECTIONS_PER_UID_MAX > m)
2548 return m / 4 * 3;
2549
2550 return VARLINK_DEFAULT_CONNECTIONS_PER_UID_MAX;
2551 }
2552
2553 int varlink_server_set_connections_per_uid_max(VarlinkServer *s, unsigned m) {
2554 assert_return(s, -EINVAL);
2555 assert_return(m > 0, -EINVAL);
2556
2557 s->connections_per_uid_max = m;
2558 return 0;
2559 }
2560
2561 int varlink_server_set_connections_max(VarlinkServer *s, unsigned m) {
2562 assert_return(s, -EINVAL);
2563 assert_return(m > 0, -EINVAL);
2564
2565 s->connections_max = m;
2566 return 0;
2567 }
2568
2569 unsigned varlink_server_current_connections(VarlinkServer *s) {
2570 assert_return(s, UINT_MAX);
2571
2572 return s->n_connections;
2573 }
2574
2575 int varlink_server_set_description(VarlinkServer *s, const char *description) {
2576 assert_return(s, -EINVAL);
2577
2578 return free_and_strdup(&s->description, description);
2579 }
Unnamed repository; edit this file 'description' to name the repository.