Merge topic branch t/ff-compat into master
[paraslash.git] / afs.c
1 /* Copyright (C) 2007 Andre Noll <maan@tuebingen.mpg.de>, see file COPYING. */
2
3 /** \file afs.c Paraslash's audio file selector. */
4
5 #include <netinet/in.h>
6 #include <sys/socket.h>
7 #include <regex.h>
8 #include <signal.h>
9 #include <fnmatch.h>
10 #include <osl.h>
11 #include <lopsub.h>
12 #include <arpa/inet.h>
13 #include <sys/un.h>
14 #include <netdb.h>
15 #include <lopsub.h>
16
17 #include "server.lsg.h"
18 #include "server_cmd.lsg.h"
19 #include "para.h"
20 #include "error.h"
21 #include "crypt.h"
22 #include "string.h"
23 #include "afh.h"
24 #include "afs.h"
25 #include "net.h"
26 #include "server.h"
27 #include "daemon.h"
28 #include "ipc.h"
29 #include "list.h"
30 #include "sched.h"
31 #include "fd.h"
32 #include "signal.h"
33 #include "sideband.h"
34 #include "command.h"
35
36 /**
37 * The array of tables of the audio file selector.
38 *
39 * We organize them in an array to be able to loop over all tables.
40 */
41 static const struct afs_table {
42 /** The name is no table operation, so define it here. */
43 const char * const name;
44 /** The only way to invoke the ops is via this pointer. */
45 const struct afs_table_operations *ops;
46 } afs_tables[] = {
47 {.name = "audio_files", .ops = &aft_ops},
48 {.name = "attributes", .ops = &attr_ops},
49 {.name = "scores", .ops = &score_ops},
50 {.name = "moods", .ops = &moods_ops},
51 {.name = "lyrics", .ops = &lyrics_ops},
52 {.name = "images", .ops = &images_ops},
53 {.name = "playlists", .ops = &playlists_ops},
54 };
55 /** Used to loop over the afs tables. */
56 #define NUM_AFS_TABLES ARRAY_SIZE(afs_tables)
57
58 struct command_task {
59 /** The file descriptor for the local socket. */
60 int fd;
61 /** The associated task structure. */
62 struct task *task;
63 };
64
65 extern int mmd_mutex;
66 extern struct misc_meta_data *mmd;
67
68 static int server_socket;
69 static struct command_task command_task_struct;
70 static struct signal_task *signal_task;
71
72 static enum play_mode current_play_mode;
73 static char *current_mop; /* mode or playlist specifier. NULL means dummy mood */
74
75 extern uint32_t afs_socket_cookie;
76
77 /**
78 * Passed from command handlers to afs.
79 *
80 * Command handlers cannot change the afs database directly because they run in
81 * a separate process. The callback query structure circumvents this
82 * restriction as follows. To instruct the afs process to execute a particular
83 * function, the command hander writes an instance of this structure to a
84 * shared memory area, along with the arguments to the callback function. The
85 * identifier of the shared memory area is transferred to the afs process via
86 * the command socket.
87 *
88 * The afs process reads the shared memory id from the command socket, attaches
89 * the corresponding area, and calls the callback function whose address is
90 * stored in the area.
91 *
92 * The command output, if any, is transferred back to the command handler in
93 * the same way: The afs process writes the output to a second shared memory
94 * area together with a fixed size metadata header whose format corresponds to
95 * the \ref callback_result structure. The identifier of this area is sent back
96 * to the command handler which attaches the area and forwards the output to
97 * the remote client.
98 *
99 * \sa \ref struct callback_result.
100 */
101 struct callback_query {
102 /** The function to be called. */
103 afs_callback *cb;
104 /** The number of bytes of the query */
105 size_t query_size;
106 };
107
108 /**
109 * Structure embedded in the result of a callback.
110 *
111 * If the callback produced a result, an instance of that structure is embedded
112 * into the shared memory area holding the result, mainly to let the command
113 * handler know the size of the result.
114 *
115 * \sa \ref struct callback_query.
116 */
117 struct callback_result {
118 /** The number of bytes of the result. */
119 size_t result_size;
120 /** The band designator (loglevel for the result). */
121 uint8_t band;
122 };
123
124 static int dispatch_result(int result_shmid, callback_result_handler *handler,
125 void *private_result_data)
126 {
127 struct osl_object result;
128 void *result_shm;
129 /* must attach r/w as result.data might get encrypted in-place. */
130 int ret2, ret = shm_attach(result_shmid, ATTACH_RW, &result_shm);
131 struct callback_result *cr = result_shm;
132
133 if (ret < 0) {
134 PARA_ERROR_LOG("attach failed: %s\n", para_strerror(-ret));
135 return ret;
136 }
137 result.size = cr->result_size;
138 result.data = result_shm + sizeof(*cr);
139 assert(handler);
140 ret = handler(&result, cr->band, private_result_data);
141 ret2 = shm_detach(result_shm);
142 if (ret2 < 0) {
143 PARA_ERROR_LOG("detach failed: %s\n", para_strerror(-ret2));
144 if (ret >= 0)
145 ret = ret2;
146 }
147 return ret;
148 }
149
150 /**
151 * Ask the afs process to call a given function.
152 *
153 * \param f The function to be called.
154 * \param query Pointer to arbitrary data for the callback.
155 * \param result_handler Called for each shm area sent by the callback.
156 * \param private_result_data Passed verbatim to \a result_handler.
157 *
158 * This function creates a socket for communication with the afs process and a
159 * shared memory area (sma) to which the buffer pointed to by \a query is
160 * copied. It then notifies the afs process that the callback function \a f
161 * should be executed by sending the shared memory identifier (shmid) to the
162 * socket.
163 *
164 * If the callback produces a result, it sends any number of shared memory
165 * identifiers back via the socket. For each such identifier received, \a
166 * result_handler is called. The contents of the sma identified by the received
167 * shmid are passed to that function as an osl object. The private_result_data
168 * pointer is passed as the second argument to \a result_handler.
169 *
170 * \return Number of shared memory areas dispatched on success, negative on
171 * errors.
172 */
173 int send_callback_request(afs_callback *f, struct osl_object *query,
174 callback_result_handler *result_handler,
175 void *private_result_data)
176 {
177 struct callback_query *cq;
178 int ret, fd = -1, query_shmid, result_shmid;
179 void *query_shm;
180 char buf[sizeof(afs_socket_cookie) + sizeof(int)];
181 size_t query_shm_size = sizeof(*cq);
182 int dispatch_error = 0, num_dispatched = 0;
183
184 if (query)
185 query_shm_size += query->size;
186 ret = shm_new(query_shm_size);
187 if (ret < 0)
188 return ret;
189 query_shmid = ret;
190 ret = shm_attach(query_shmid, ATTACH_RW, &query_shm);
191 if (ret < 0)
192 goto out;
193 cq = query_shm;
194 cq->cb = f;
195 cq->query_size = query_shm_size - sizeof(*cq);
196
197 if (query)
198 memcpy(query_shm + sizeof(*cq), query->data, query->size);
199 ret = shm_detach(query_shm);
200 if (ret < 0)
201 goto out;
202
203 *(uint32_t *)buf = afs_socket_cookie;
204 *(int *)(buf + sizeof(afs_socket_cookie)) = query_shmid;
205
206 ret = connect_local_socket(OPT_STRING_VAL(AFS_SOCKET));
207 if (ret < 0)
208 goto out;
209 fd = ret;
210 ret = write_all(fd, buf, sizeof(buf));
211 if (ret < 0)
212 goto out;
213 /*
214 * Read all shmids from afs.
215 *
216 * Even if the dispatcher returns an error we _must_ continue to read
217 * shmids from fd so that we can destroy all shared memory areas that
218 * have been created for us by the afs process.
219 */
220 for (;;) {
221 ret = recv_bin_buffer(fd, buf, sizeof(int));
222 if (ret <= 0)
223 goto out;
224 assert(ret == sizeof(int));
225 ret = *(int *) buf;
226 assert(ret > 0);
227 result_shmid = ret;
228 ret = dispatch_result(result_shmid, result_handler,
229 private_result_data);
230 if (ret < 0 && dispatch_error >= 0)
231 dispatch_error = ret;
232 ret = shm_destroy(result_shmid);
233 if (ret < 0)
234 PARA_CRIT_LOG("destroy result failed: %s\n",
235 para_strerror(-ret));
236 num_dispatched++;
237 }
238 out:
239 if (shm_destroy(query_shmid) < 0)
240 PARA_CRIT_LOG("shm destroy error\n");
241 if (fd >= 0)
242 close(fd);
243 if (dispatch_error < 0)
244 return dispatch_error;
245 if (ret < 0)
246 return ret;
247 return num_dispatched;
248 }
249
250 /**
251 * Wrapper for send_callback_request() which passes a lopsub parse result.
252 *
253 * \param f The callback function.
254 * \param cmd Needed for (de-)serialization.
255 * \param lpr Must match cmd.
256 * \param private_result_data Passed to send_callback_request().
257 *
258 * This function serializes the parse result given by the lpr pointer into a
259 * buffer. The buffer is sent as the query to the afs process with the callback
260 * mechanism.
261 *
262 * \return The return value of the underlying call to send_callback_request().
263 */
264 int send_lls_callback_request(afs_callback *f,
265 const struct lls_command * const cmd,
266 struct lls_parse_result *lpr, void *private_result_data)
267 {
268 struct osl_object query;
269 char *buf = NULL;
270 int ret = lls_serialize_parse_result(lpr, cmd, &buf, &query.size);
271
272 assert(ret >= 0);
273 query.data = buf;
274 ret = send_callback_request(f, &query, afs_cb_result_handler,
275 private_result_data);
276 free(buf);
277 return ret;
278 }
279
280 static int action_if_pattern_matches(struct osl_row *row, void *data)
281 {
282 struct pattern_match_data *pmd = data;
283 struct osl_object name_obj;
284 const char *p, *name;
285 int i, ret;
286
287 ret = osl(osl_get_object(pmd->table, row, pmd->match_col_num,
288 &name_obj));
289 if (ret < 0)
290 return ret;
291 name = (char *)name_obj.data;
292 if ((!name || !*name) && (pmd->pm_flags & PM_SKIP_EMPTY_NAME))
293 return 1;
294 if (lls_num_inputs(pmd->lpr) == 0) {
295 if (pmd->pm_flags & PM_NO_PATTERN_MATCHES_EVERYTHING) {
296 pmd->num_matches++;
297 return pmd->action(pmd->table, row, name, pmd->data);
298 }
299 }
300 i = pmd->input_skip;
301 for (;;) {
302 if (i >= lls_num_inputs(pmd->lpr))
303 break;
304 p = lls_input(i, pmd->lpr);
305 ret = fnmatch(p, name, pmd->fnmatch_flags);
306 if (ret != FNM_NOMATCH) {
307 if (ret != 0)
308 return -E_FNMATCH;
309 ret = pmd->action(pmd->table, row, name, pmd->data);
310 if (ret >= 0)
311 pmd->num_matches++;
312 return ret;
313
314 }
315 i++;
316 }
317 return 1;
318 }
319
320 /**
321 * Execute the given function for each matching row.
322 *
323 * \param pmd Describes what to match and how.
324 *
325 * \return Standard.
326 */
327 int for_each_matching_row(struct pattern_match_data *pmd)
328 {
329 if (pmd->pm_flags & PM_REVERSE_LOOP)
330 return osl(osl_rbtree_loop_reverse(pmd->table, pmd->loop_col_num, pmd,
331 action_if_pattern_matches));
332 return osl(osl_rbtree_loop(pmd->table, pmd->loop_col_num, pmd,
333 action_if_pattern_matches));
334 }
335
336 /**
337 * Compare two osl objects of string type.
338 *
339 * \param obj1 Pointer to the first object.
340 * \param obj2 Pointer to the second object.
341 *
342 * In any case, only \p MIN(obj1->size, obj2->size) characters of each string
343 * are taken into account.
344 *
345 * \return It returns an integer less than, equal to, or greater than zero if
346 * \a obj1 is found, respectively, to be less than, to match, or be greater than
347 * obj2.
348 *
349 * \sa strcmp(3), strncmp(3).
350 */
351 int string_compare(const struct osl_object *obj1, const struct osl_object *obj2)
352 {
353 const char *str1 = obj1->data;
354 const char *str2 = obj2->data;
355 return strncmp(str1, str2, PARA_MIN(obj1->size, obj2->size));
356 }
357
358 static int pass_afd(int fd, char *buf, size_t size)
359 {
360 struct msghdr msg = {.msg_iov = NULL};
361 struct cmsghdr *cmsg;
362 char control[255] __a_aligned(8);
363 int ret;
364 struct iovec iov;
365
366 iov.iov_base = buf;
367 iov.iov_len = size;
368
369 msg.msg_iov = &iov;
370 msg.msg_iovlen = 1;
371
372 msg.msg_control = control;
373 msg.msg_controllen = sizeof(control);
374
375 cmsg = CMSG_FIRSTHDR(&msg);
376 cmsg->cmsg_level = SOL_SOCKET;
377 cmsg->cmsg_type = SCM_RIGHTS;
378 cmsg->cmsg_len = CMSG_LEN(sizeof(int));
379 *(int *)CMSG_DATA(cmsg) = fd;
380
381 /* Sum of the length of all control messages in the buffer */
382 msg.msg_controllen = cmsg->cmsg_len;
383 PARA_DEBUG_LOG("passing %zu bytes and fd %d\n", size, fd);
384 ret = sendmsg(server_socket, &msg, 0);
385 if (ret < 0) {
386 ret = -ERRNO_TO_PARA_ERROR(errno);
387 return ret;
388 }
389 return 1;
390 }
391
392 /**
393 * Pass the fd of the next audio file to the server process.
394 *
395 * This stores all information for streaming the "best" audio file in a shared
396 * memory area. The id of that area and an open file descriptor for the next
397 * audio file are passed to the server process.
398 *
399 * \return Standard.
400 *
401 * \sa \ref open_and_update_audio_file().
402 */
403 static int open_next_audio_file(void)
404 {
405 int ret, shmid, fd;
406 char buf[8];
407
408 ret = open_and_update_audio_file(&fd);
409 if (ret < 0) {
410 if (ret != -OSL_ERRNO_TO_PARA_ERROR(E_OSL_RB_KEY_NOT_FOUND))
411 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
412 goto no_admissible_files;
413 }
414 shmid = ret;
415 if (!write_ok(server_socket)) {
416 ret = -E_AFS_SOCKET;
417 goto destroy;
418 }
419 *(uint32_t *)buf = NEXT_AUDIO_FILE;
420 *(uint32_t *)(buf + 4) = (uint32_t)shmid;
421 ret = pass_afd(fd, buf, 8);
422 close(fd);
423 if (ret >= 0)
424 return ret;
425 destroy:
426 shm_destroy(shmid);
427 return ret;
428 no_admissible_files:
429 *(uint32_t *)buf = NO_ADMISSIBLE_FILES;
430 *(uint32_t *)(buf + 4) = (uint32_t)0;
431 return write_all(server_socket, buf, 8);
432 }
433
434 static int activate_mood_or_playlist(const char *arg, struct para_buffer *pb)
435 {
436 enum play_mode mode;
437 int ret;
438 char *msg;
439
440 if (!arg) {
441 ret = mood_load(NULL, &msg);
442 mode = PLAY_MODE_MOOD;
443 } else if (!strncmp(arg, "p/", 2)) {
444 ret = playlist_load(arg + 2, &msg);
445 mode = PLAY_MODE_PLAYLIST;
446 } else if (!strncmp(arg, "m/", 2)) {
447 ret = mood_load(arg + 2, &msg);
448 mode = PLAY_MODE_MOOD;
449 } else {
450 ret = -ERRNO_TO_PARA_ERROR(EINVAL);
451 msg = make_message("%s: parse error", arg);
452 }
453 if (pb)
454 para_printf(pb, "%s", msg);
455 free(msg);
456 if (ret < 0)
457 return ret;
458 current_play_mode = mode;
459 /*
460 * We get called with arg == current_mop from the signal dispatcher
461 * after SIGHUP and from the error path of the select command to
462 * re-select the current mood or playlist. In this case the assignment
463 * to current_mop below would result in a use-after-free condition.
464 */
465 if (arg != current_mop) {
466 free(current_mop);
467 current_mop = arg? para_strdup(arg) : NULL;
468 }
469 /* Notify the server about the mood/playlist change. */
470 mutex_lock(mmd_mutex);
471 strncpy(mmd->afs_mode_string, arg? arg: "dummy",
472 sizeof(mmd->afs_mode_string));
473 mmd->afs_mode_string[sizeof(mmd->afs_mode_string) - 1] = '\0';
474 mmd->events++;
475 mutex_unlock(mmd_mutex);
476 return 1;
477 }
478
479 /**
480 * Result handler for sending data to the para_client process.
481 *
482 * \param result The data to be sent.
483 * \param band The band designator.
484 * \param private Pointer to the command context.
485 *
486 * \return The return value of the underlying call to \ref command.c::send_sb.
487 *
488 * \sa \ref callback_result_handler, \ref command.c::send_sb.
489 */
490 int afs_cb_result_handler(struct osl_object *result, uint8_t band,
491 void *private)
492 {
493 struct command_context *cc = private;
494
495 assert(cc);
496 switch (band) {
497 case SBD_OUTPUT:
498 case SBD_DEBUG_LOG:
499 case SBD_INFO_LOG:
500 case SBD_NOTICE_LOG:
501 case SBD_WARNING_LOG:
502 case SBD_ERROR_LOG:
503 case SBD_CRIT_LOG:
504 case SBD_EMERG_LOG:
505 assert(result->size > 0);
506 return send_sb(&cc->scc, result->data, result->size, band, true);
507 case SBD_AFS_CB_FAILURE:
508 return *(int *)(result->data);
509 default:
510 return -E_BAD_BAND;
511 }
512 }
513
514 static void flush_and_free_pb(struct para_buffer *pb)
515 {
516 int ret;
517 struct afs_max_size_handler_data *amshd = pb->private_data;
518
519 if (pb->buf && pb->size > 0) {
520 ret = pass_buffer_as_shm(amshd->fd, amshd->band, pb->buf,
521 pb->offset);
522 if (ret < 0)
523 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
524 }
525 free(pb->buf);
526 }
527
528 static void init_admissible_files(const char *arg)
529 {
530 int ret = activate_mood_or_playlist(arg, NULL);
531 if (ret < 0) {
532 PARA_WARNING_LOG("could not activate %s: %s\n", arg,
533 para_strerror(-ret));
534 if (arg)
535 activate_mood_or_playlist(NULL, NULL);
536 }
537 }
538
539 static int setup_command_socket_or_die(void)
540 {
541 int ret, socket_fd;
542 const char *socket_name = OPT_STRING_VAL(AFS_SOCKET);
543
544 unlink(socket_name);
545 ret = create_local_socket(socket_name);
546 if (ret < 0) {
547 PARA_EMERG_LOG("%s: %s\n", para_strerror(-ret), socket_name);
548 exit(EXIT_FAILURE);
549 }
550 socket_fd = ret;
551 PARA_INFO_LOG("listening on socket %s (fd %d)\n", socket_name,
552 socket_fd);
553 return socket_fd;
554 }
555
556 static char *database_dir;
557
558 static void close_afs_tables(void)
559 {
560 int i;
561 PARA_NOTICE_LOG("closing afs tables\n");
562 for (i = 0; i < NUM_AFS_TABLES; i++)
563 afs_tables[i].ops->close();
564 free(database_dir);
565 database_dir = NULL;
566 }
567
568 static void get_database_dir(void)
569 {
570 if (!database_dir) {
571 if (OPT_GIVEN(AFS_DATABASE_DIR))
572 database_dir = para_strdup(OPT_STRING_VAL(AFS_DATABASE_DIR));
573 else {
574 char *home = para_homedir();
575 database_dir = make_message(
576 "%s/.paraslash/afs_database-0.7", home);
577 free(home);
578 }
579 }
580 PARA_INFO_LOG("afs_database dir %s\n", database_dir);
581 }
582
583 static int make_database_dir(void)
584 {
585 int ret;
586
587 get_database_dir();
588 ret = para_mkdir(database_dir, 0777);
589 if (ret >= 0 || ret == -ERRNO_TO_PARA_ERROR(EEXIST))
590 return 1;
591 return ret;
592 }
593
594 static int open_afs_tables(void)
595 {
596 int i, ret;
597
598 get_database_dir();
599 PARA_NOTICE_LOG("opening %zu osl tables in %s\n", NUM_AFS_TABLES,
600 database_dir);
601 for (i = 0; i < NUM_AFS_TABLES; i++) {
602 ret = afs_tables[i].ops->open(database_dir);
603 if (ret >= 0)
604 continue;
605 PARA_ERROR_LOG("could not open %s\n", afs_tables[i].name);
606 break;
607 }
608 if (ret >= 0)
609 return ret;
610 while (i)
611 afs_tables[--i].ops->close();
612 return ret;
613 }
614
615 static int afs_signal_post_monitor(struct sched *s, __a_unused void *context)
616 {
617 int signum, ret;
618
619 if (getppid() == 1) {
620 PARA_EMERG_LOG("para_server died\n");
621 goto shutdown;
622 }
623 signum = para_next_signal();
624 if (signum == 0)
625 return 0;
626 if (signum == SIGHUP) {
627 close_afs_tables();
628 parse_config_or_die(1);
629 ret = open_afs_tables();
630 if (ret < 0)
631 return ret;
632 init_admissible_files(current_mop);
633 return 0;
634 }
635 PARA_EMERG_LOG("terminating on signal %d\n", signum);
636 shutdown:
637 task_notify_all(s, E_AFS_SIGNAL);
638 return -E_AFS_SIGNAL;
639 }
640
641 static void register_signal_task(struct sched *s)
642 {
643 para_sigaction(SIGPIPE, SIG_IGN);
644 signal_task = signal_init_or_die();
645 para_install_sighandler(SIGINT);
646 para_install_sighandler(SIGTERM);
647 para_install_sighandler(SIGHUP);
648
649 signal_task->task = task_register(&(struct task_info) {
650 .name = "signal",
651 .pre_monitor = signal_pre_monitor,
652 .post_monitor = afs_signal_post_monitor,
653 .context = signal_task,
654
655 }, s);
656 }
657
658 static struct list_head afs_client_list;
659
660 /** Describes one connected afs client. */
661 struct afs_client {
662 /** Position in the afs client list. */
663 struct list_head node;
664 /** The socket file descriptor for this client. */
665 int fd;
666 /** The time the client connected. */
667 struct timeval connect_time;
668 };
669
670 static void command_pre_monitor(struct sched *s, void *context)
671 {
672 struct command_task *ct = context;
673 struct afs_client *client;
674
675 sched_monitor_readfd(server_socket, s);
676 sched_monitor_readfd(ct->fd, s);
677 list_for_each_entry(client, &afs_client_list, node)
678 sched_monitor_readfd(client->fd, s);
679 }
680
681 /**
682 * Send data as shared memory to a file descriptor.
683 *
684 * \param fd File descriptor to send the shmid to.
685 * \param band The band designator for this data.
686 * \param buf The buffer holding the data to be sent.
687 * \param size The size of \a buf.
688 *
689 * This function creates a shared memory area large enough to hold
690 * the content given by \a buf and \a size and sends the identifier
691 * of this area to the file descriptor \a fd.
692 *
693 * It is called by the AFS max_size handler as well as directly by the AFS
694 * command callbacks to send command output to the command handlers.
695 *
696 * \return Zero if \a buf is \p NULL or \a size is zero. Negative on errors,
697 * and positive on success.
698 */
699 int pass_buffer_as_shm(int fd, uint8_t band, const char *buf, size_t size)
700 {
701 int ret, shmid;
702 void *shm;
703 struct callback_result *cr;
704
705 if (size == 0)
706 assert(band != SBD_OUTPUT);
707 ret = shm_new(size + sizeof(*cr));
708 if (ret < 0)
709 return ret;
710 shmid = ret;
711 ret = shm_attach(shmid, ATTACH_RW, &shm);
712 if (ret < 0)
713 goto err;
714 cr = shm;
715 cr->result_size = size;
716 cr->band = band;
717 if (size > 0)
718 memcpy(shm + sizeof(*cr), buf, size);
719 ret = shm_detach(shm);
720 if (ret < 0)
721 goto err;
722 ret = write_all(fd, (char *)&shmid, sizeof(int));
723 if (ret >= 0)
724 return ret;
725 err:
726 if (shm_destroy(shmid) < 0)
727 PARA_ERROR_LOG("destroy result failed\n");
728 return ret;
729 }
730
731 /**
732 * Format and send an error message to the command handler.
733 *
734 * To pass an error message from the callback of an afs command to the client,
735 * this function should be called. It formats the message into a buffer which
736 * is passed as a shared memory area to the command handler from where it
737 * propagates to the client.
738 *
739 * The message will be tagged with the ERROR_LOG sideband designator so that
740 * the client writes it to its stderr stream rather than to stdout as with
741 * aca->pbout. In analogy to the default Unix semantics of stderr, the message
742 * is sent without buffering.
743 *
744 * If sending the error message fails, an error is logged on the server side,
745 * but no other action is taken.
746 *
747 * \param aca Used to obtain the fd to send the shmid to.
748 * \param fmt Usual format string.
749 */
750 __printf_2_3 void afs_error(const struct afs_callback_arg *aca,
751 const char *fmt,...)
752 {
753 va_list argp;
754 char *msg;
755 unsigned n;
756 int ret;
757
758 va_start(argp, fmt);
759 n = xvasprintf(&msg, fmt, argp);
760 va_end(argp);
761 ret = pass_buffer_as_shm(aca->fd, SBD_ERROR_LOG, msg, n + 1);
762 if (ret < 0)
763 PARA_ERROR_LOG("Could not send %s: %s\n", msg,
764 para_strerror(-ret));
765 free(msg);
766 }
767
768 static int call_callback(int fd, int query_shmid)
769 {
770 void *query_shm;
771 struct callback_query *cq;
772 int ret, ret2;
773 struct afs_callback_arg aca = {.fd = fd};
774
775 ret = shm_attach(query_shmid, ATTACH_RW, &query_shm);
776 if (ret < 0)
777 return ret;
778 cq = query_shm;
779 aca.query.data = (char *)query_shm + sizeof(*cq);
780 aca.query.size = cq->query_size;
781 aca.pbout.max_size = shm_get_shmmax();
782 aca.pbout.max_size_handler = afs_max_size_handler;
783 aca.pbout.private_data = &(struct afs_max_size_handler_data) {
784 .fd = fd,
785 .band = SBD_OUTPUT
786 };
787 ret = cq->cb(&aca);
788 ret2 = shm_detach(query_shm);
789 if (ret2 < 0) {
790 if (ret < 0) /* ignore (but log) detach error */
791 PARA_ERROR_LOG("could not detach sma: %s\n",
792 para_strerror(-ret2));
793 else
794 ret = ret2;
795 }
796 flush_and_free_pb(&aca.pbout);
797 if (ret < 0) {
798 ret2 = pass_buffer_as_shm(fd, SBD_AFS_CB_FAILURE,
799 (const char *)&ret, sizeof(ret));
800 if (ret2 < 0)
801 PARA_ERROR_LOG("could not pass cb failure packet: %s\n",
802 para_strerror(-ret));
803 }
804 return ret;
805 }
806
807 static int execute_server_command(void)
808 {
809 char buf[8];
810 size_t n;
811 int ret = read_nonblock(server_socket, buf, sizeof(buf) - 1, &n);
812
813 if (ret < 0 || n == 0)
814 return ret;
815 buf[n] = '\0';
816 if (strcmp(buf, "new"))
817 return -ERRNO_TO_PARA_ERROR(EINVAL);
818 return open_next_audio_file();
819 }
820
821 /* returns 0 if no data available, 1 else */
822 static int execute_afs_command(int fd)
823 {
824 uint32_t cookie;
825 int query_shmid;
826 char buf[sizeof(cookie) + sizeof(query_shmid)];
827 size_t n;
828 int ret = read_nonblock(fd, buf, sizeof(buf), &n);
829
830 if (ret < 0)
831 goto err;
832 if (n == 0)
833 return 0;
834 if (n != sizeof(buf)) {
835 PARA_NOTICE_LOG("short read (%d bytes, expected %lu)\n",
836 ret, (long unsigned) sizeof(buf));
837 return 1;
838 }
839 cookie = *(uint32_t *)buf;
840 if (cookie != afs_socket_cookie) {
841 PARA_NOTICE_LOG("received invalid cookie (got %u, expected %u)\n",
842 (unsigned)cookie, (unsigned)afs_socket_cookie);
843 return 1;
844 }
845 query_shmid = *(int *)(buf + sizeof(cookie));
846 if (query_shmid < 0) {
847 PARA_WARNING_LOG("received invalid query shmid %d)\n",
848 query_shmid);
849 return 1;
850 }
851 ret = call_callback(fd, query_shmid);
852 if (ret >= 0)
853 return 1;
854 err:
855 PARA_NOTICE_LOG("%s\n", para_strerror(-ret));
856 return 1;
857 }
858
859 /** Shutdown connection if query has not arrived until this many seconds. */
860 #define AFS_CLIENT_TIMEOUT 3
861
862 static int command_post_monitor(struct sched *s, void *context)
863 {
864 struct command_task *ct = context;
865 struct sockaddr_un unix_addr;
866 struct afs_client *client, *tmp;
867 int fd, ret;
868
869 ret = task_get_notification(ct->task);
870 if (ret < 0)
871 return ret;
872 ret = execute_server_command();
873 if (ret < 0) {
874 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
875 task_notify_all(s, -ret);
876 return ret;
877 }
878 /* Check the list of connected clients. */
879 list_for_each_entry_safe(client, tmp, &afs_client_list, node) {
880 ret = execute_afs_command(client->fd);
881 if (ret == 0) { /* prevent bogus connection flooding */
882 struct timeval diff;
883 tv_diff(now, &client->connect_time, &diff);
884 if (diff.tv_sec < AFS_CLIENT_TIMEOUT)
885 continue;
886 PARA_WARNING_LOG("connection timeout\n");
887 }
888 close(client->fd);
889 list_del(&client->node);
890 free(client);
891 }
892 /* Accept connections on the local socket. */
893 ret = para_accept(ct->fd, &unix_addr, sizeof(unix_addr), &fd);
894 if (ret < 0)
895 PARA_NOTICE_LOG("%s\n", para_strerror(-ret));
896 if (ret <= 0)
897 return 0;
898 ret = mark_fd_nonblocking(fd);
899 if (ret < 0) {
900 PARA_NOTICE_LOG("%s\n", para_strerror(-ret));
901 close(fd);
902 return 0;
903 }
904 client = alloc(sizeof(*client));
905 client->fd = fd;
906 client->connect_time = *now;
907 para_list_add(&client->node, &afs_client_list);
908 return 0;
909 }
910
911 static void register_command_task(struct sched *s)
912 {
913 struct command_task *ct = &command_task_struct;
914 ct->fd = setup_command_socket_or_die();
915
916 ct->task = task_register(&(struct task_info) {
917 .name = "afs command",
918 .pre_monitor = command_pre_monitor,
919 .post_monitor = command_post_monitor,
920 .context = ct,
921 }, s);
922 }
923
924 static int afs_poll(struct pollfd *fds, nfds_t nfds, int timeout)
925 {
926 mutex_lock(mmd_mutex);
927 daemon_set_loglevel(mmd->loglevel);
928 mutex_unlock(mmd_mutex);
929 return xpoll(fds, nfds, timeout);
930 }
931
932 /**
933 * Initialize the audio file selector process.
934 *
935 * \param socket_fd File descriptor used for communication with the server.
936 */
937 __noreturn void afs_init(int socket_fd)
938 {
939 static struct sched s;
940 int ret;
941
942 register_signal_task(&s);
943 init_list_head(&afs_client_list);
944 ret = open_afs_tables();
945 if (ret < 0)
946 goto out;
947 server_socket = socket_fd;
948 ret = mark_fd_nonblocking(server_socket);
949 if (ret < 0)
950 goto out_close;
951 PARA_INFO_LOG("server_socket: %d\n", server_socket);
952 init_admissible_files(OPT_STRING_VAL(AFS_INITIAL_MODE));
953 register_command_task(&s);
954 s.default_timeout = 1000;
955 s.poll_function = afs_poll;
956 ret = write(socket_fd, "\0", 1);
957 if (ret != 1) {
958 if (ret == 0)
959 errno = EINVAL;
960 ret = -ERRNO_TO_PARA_ERROR(errno);
961 goto out_close;
962 }
963 ret = schedule(&s);
964 sched_shutdown(&s);
965 mood_unload();
966 out_close:
967 close_afs_tables();
968 out:
969 signal_shutdown(signal_task);
970 free_status_items();
971 free(current_mop);
972 free_lpr();
973 if (ret < 0)
974 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
975 exit(EXIT_FAILURE);
976 }
977
978 static int com_select_callback(struct afs_callback_arg *aca)
979 {
980 const struct lls_command *cmd = SERVER_CMD_CMD_PTR(SELECT);
981 const char *arg;
982 int ret;
983
984 ret = lls_deserialize_parse_result(aca->query.data, cmd, &aca->lpr);
985 assert(ret >= 0);
986 arg = lls_input(0, aca->lpr);
987 score_clear();
988 if (current_play_mode == PLAY_MODE_MOOD)
989 mood_unload();
990 else
991 playlist_unload();
992 ret = activate_mood_or_playlist(arg, &aca->pbout);
993 if (ret >= 0)
994 goto free_lpr;
995 /* ignore subsequent errors (but log them) */
996 if (current_mop && strcmp(current_mop, arg) != 0) {
997 int ret2;
998 afs_error(aca, "switching back to %s\n", current_mop);
999 ret2 = activate_mood_or_playlist(current_mop, &aca->pbout);
1000 if (ret2 >= 0)
1001 goto free_lpr;
1002 afs_error(aca, "could not reactivate %s: %s\n", current_mop,
1003 para_strerror(-ret2));
1004 }
1005 activate_mood_or_playlist(NULL, &aca->pbout);
1006 free_lpr:
1007 lls_free_parse_result(aca->lpr, cmd);
1008 return ret;
1009 }
1010
1011 static int com_select(struct command_context *cc, struct lls_parse_result *lpr)
1012 {
1013 const struct lls_command *cmd = SERVER_CMD_CMD_PTR(SELECT);
1014 char *errctx;
1015 int ret = lls(lls_check_arg_count(lpr, 1, 1, &errctx));
1016
1017 if (ret < 0) {
1018 send_errctx(cc, errctx);
1019 return ret;
1020 }
1021 return send_lls_callback_request(com_select_callback, cmd, lpr, cc);
1022 }
1023 EXPORT_SERVER_CMD_HANDLER(select);
1024
1025 static int com_init_callback(struct afs_callback_arg *aca)
1026 {
1027 uint32_t table_mask = *(uint32_t *)aca->query.data;
1028 int i, ret;
1029
1030 close_afs_tables();
1031 get_database_dir();
1032 for (i = 0; i < NUM_AFS_TABLES; i++) {
1033 const struct afs_table *t = afs_tables + i;
1034
1035 if (!(table_mask & (1 << i)))
1036 continue;
1037 if (!t->ops->create)
1038 continue;
1039 ret = t->ops->create(database_dir);
1040 if (ret < 0) {
1041 afs_error(aca, "cannot create table %s\n", t->name);
1042 goto out;
1043 }
1044 para_printf(&aca->pbout, "successfully created %s table\n",
1045 t->name);
1046 }
1047 ret = open_afs_tables();
1048 if (ret < 0)
1049 afs_error(aca, "cannot open afs tables: %s\n",
1050 para_strerror(-ret));
1051 out:
1052 return ret;
1053 }
1054
1055 static int com_init(struct command_context *cc, struct lls_parse_result *lpr)
1056 {
1057 int i, j, ret;
1058 uint32_t table_mask = (1 << (NUM_AFS_TABLES + 1)) - 1;
1059 struct osl_object query = {.data = &table_mask,
1060 .size = sizeof(table_mask)};
1061 unsigned num_inputs = lls_num_inputs(lpr);
1062
1063 ret = make_database_dir();
1064 if (ret < 0)
1065 return ret;
1066 if (num_inputs > 0) {
1067 table_mask = 0;
1068 for (i = 0; i < num_inputs; i++) {
1069 for (j = 0; j < NUM_AFS_TABLES; j++) {
1070 const struct afs_table *t = afs_tables + j;
1071
1072 if (strcmp(lls_input(i, lpr), t->name))
1073 continue;
1074 table_mask |= (1 << j);
1075 break;
1076 }
1077 if (j == NUM_AFS_TABLES)
1078 return -E_BAD_TABLE_NAME;
1079 }
1080 }
1081 return send_callback_request(com_init_callback, &query,
1082 afs_cb_result_handler, cc);
1083 }
1084 EXPORT_SERVER_CMD_HANDLER(init);
1085
1086 static int com_check(struct command_context *cc, struct lls_parse_result *lpr)
1087 {
1088 const struct lls_opt_result *r_a = SERVER_CMD_OPT_RESULT(CHECK, AFT, lpr);
1089 const struct lls_opt_result *r_A = SERVER_CMD_OPT_RESULT(CHECK, ATTRIBUTE, lpr);
1090 const struct lls_opt_result *r_m = SERVER_CMD_OPT_RESULT(CHECK, MOOD, lpr);
1091 const struct lls_opt_result *r_p = SERVER_CMD_OPT_RESULT(CHECK, PLAYLIST, lpr);
1092 bool noopt = !lls_opt_given(r_a) && !lls_opt_given(r_A)
1093 && !lls_opt_given(r_m) && !lls_opt_given(r_p);
1094 int ret;
1095
1096 if (noopt || lls_opt_given(r_a)) {
1097 ret = send_callback_request(aft_check_callback, NULL,
1098 afs_cb_result_handler, cc);
1099 if (ret < 0)
1100 return ret;
1101 }
1102 if (noopt || lls_opt_given(r_A)) {
1103 ret = send_callback_request(attribute_check_callback, NULL,
1104 afs_cb_result_handler, cc);
1105 if (ret < 0)
1106 return ret;
1107 }
1108 if (noopt || lls_opt_given(r_p)) {
1109 ret = send_callback_request(playlist_check_callback,
1110 NULL, afs_cb_result_handler, cc);
1111 if (ret < 0)
1112 return ret;
1113 }
1114 if (noopt || lls_opt_given(r_m)) {
1115 ret = send_callback_request(mood_check_callback, NULL,
1116 afs_cb_result_handler, cc);
1117 if (ret < 0)
1118 return ret;
1119 }
1120 return 1;
1121 }
1122 EXPORT_SERVER_CMD_HANDLER(check);
1123
1124 /**
1125 * The afs event dispatcher.
1126 *
1127 * \param event Type of the event.
1128 * \param pb May be \p NULL.
1129 * \param data Type depends on \a event.
1130 *
1131 * This function calls each table event handler, passing \a pb and \a data
1132 * verbatim. It's up to the handlers to interpret the \a data pointer. If a
1133 * handler returns negative, the loop is aborted.
1134 *
1135 * \return The (negative) error code of the first handler that failed, or non-negative
1136 * if all handlers succeeded.
1137 */
1138 __must_check int afs_event(enum afs_events event, struct para_buffer *pb,
1139 void *data)
1140 {
1141 int i, ret;
1142
1143 for (i = 0; i < NUM_AFS_TABLES; i++) {
1144 const struct afs_table *t = afs_tables + i;
1145 if (!t->ops->event_handler)
1146 continue;
1147 ret = t->ops->event_handler(event, pb, data);
1148 if (ret < 0) {
1149 PARA_CRIT_LOG("table %s, event %u: %s\n", t->name,
1150 event, para_strerror(-ret));
1151 return ret;
1152 }
1153 }
1154 return 1;
1155 }
1156
1157 /**
1158 * Dummy event handler for the images table.
1159 *
1160 * \param event Unused.
1161 * \param pb Unused.
1162 * \param data Unused.
1163 *
1164 * \return The images table does not honor events, so this handler always
1165 * returns success.
1166 */
1167 __a_const int images_event_handler(__a_unused enum afs_events event,
1168 __a_unused struct para_buffer *pb, __a_unused void *data)
1169 {
1170 return 1;
1171 }
1172
1173 /**
1174 * Dummy event handler for the lyrics table.
1175 *
1176 * \param event Unused.
1177 * \param pb Unused.
1178 * \param data Unused.
1179 *
1180 * \return The lyrics table does not honor events, so this handler always
1181 * returns success.
1182 */
1183 __a_const int lyrics_event_handler(__a_unused enum afs_events event,
1184 __a_unused struct para_buffer *pb, __a_unused void *data)
1185 {
1186 return 1;
1187 }