command_util: Write array definition in header mode.
[paraslash.git] / command.c
1 /*
2 * Copyright (C) 1997-2012 Andre Noll <maan@systemlinux.org>
3 *
4 * Licensed under the GPL v2. For licencing details see COPYING.
5 */
6
7 /** \file command.c Client authentication and server commands. */
8
9 #include <regex.h>
10 #include <signal.h>
11 #include <sys/time.h>
12 #include <sys/types.h>
13 #include <osl.h>
14
15 #include "para.h"
16 #include "error.h"
17 #include "crypt.h"
18 #include "sideband.h"
19 #include "command.h"
20 #include "server.cmdline.h"
21 #include "string.h"
22 #include "afh.h"
23 #include "afs.h"
24 #include "server.h"
25 #include "list.h"
26 #include "send.h"
27 #include "sched.h"
28 #include "vss.h"
29 #include "net.h"
30 #include "daemon.h"
31 #include "fd.h"
32 #include "ipc.h"
33 #include "user_list.h"
34 #include "server_command_list.h"
35 #include "afs_command_list.h"
36 #include "signal.h"
37 #include "version.h"
38
39 struct server_command afs_cmds[] = {DEFINE_AFS_CMD_ARRAY};
40 struct server_command server_cmds[] = {DEFINE_SERVER_CMD_ARRAY};
41
42 /** Commands including options must be shorter than this. */
43 #define MAX_COMMAND_LEN 32768
44
45 extern int mmd_mutex;
46 extern struct misc_meta_data *mmd;
47 extern struct sender senders[];
48 int send_afs_status(struct command_context *cc, int parser_friendly);
49
50 static void dummy(__a_unused int s)
51 {
52 }
53
54 static void mmd_dup(struct misc_meta_data *new_mmd)
55 {
56 mutex_lock(mmd_mutex);
57 *new_mmd = *mmd;
58 mutex_unlock(mmd_mutex);
59 }
60
61 /*
62 * Compute human readable string containing vss status for given integer value.
63 *
64 * We don't want to use vss_playing() and friends here because we take a
65 * snapshot of the mmd struct and use the copy for computing the state of the
66 * vss. If the real data were used, we would take the mmd lock for a rather
67 * long time or risk to get an inconsistent view.
68 */
69 static char *vss_status_tohuman(unsigned int flags)
70 {
71 if (flags & VSS_PLAYING)
72 return para_strdup("playing");
73 if (flags & VSS_NEXT)
74 return para_strdup("stopped");
75 return para_strdup("paused");
76 }
77
78 /*
79 * return human readable permission string. Never returns NULL.
80 */
81 static char *cmd_perms_itohuman(unsigned int perms)
82 {
83 char *msg = para_malloc(5 * sizeof(char));
84
85 msg[0] = perms & AFS_READ? 'a' : '-';
86 msg[1] = perms & AFS_WRITE? 'A' : '-';
87 msg[2] = perms & VSS_READ? 'v' : '-';
88 msg[3] = perms & VSS_WRITE? 'V' : '-';
89 msg[4] = '\0';
90 return msg;
91 }
92
93 /*
94 * Never returns NULL.
95 */
96 static char *vss_get_status_flags(unsigned int flags)
97 {
98 char *msg = para_malloc(5 * sizeof(char));
99
100 msg[0] = (flags & VSS_PLAYING)? 'P' : '_';
101 msg[1] = (flags & VSS_NOMORE)? 'O' : '_';
102 msg[2] = (flags & VSS_NEXT)? 'N' : '_';
103 msg[3] = (flags & VSS_REPOS)? 'R' : '_';
104 msg[4] = '\0';
105 return msg;
106 }
107
108 static unsigned get_status(struct misc_meta_data *nmmd, int parser_friendly,
109 char **result)
110 {
111 char mtime[30] = "";
112 char *status, *flags; /* vss status info */
113 /* nobody updates our version of "now" */
114 char *ut = get_server_uptime_str(NULL);
115 long offset = (nmmd->offset + 500) / 1000;
116 struct timeval current_time;
117 struct tm mtime_tm;
118 struct para_buffer b = {.flags = parser_friendly? PBF_SIZE_PREFIX : 0};
119
120 /* report real status */
121 status = vss_status_tohuman(nmmd->vss_status_flags);
122 flags = vss_get_status_flags(nmmd->vss_status_flags);
123 if (nmmd->size) { /* parent currently has an audio file open */
124 localtime_r(&nmmd->mtime, &mtime_tm);
125 strftime(mtime, 29, "%b %d %Y", &mtime_tm);
126 }
127 gettimeofday(&current_time, NULL);
128 /*
129 * The calls to WRITE_STATUS_ITEM() below never fail because
130 * b->max_size is zero (unlimited), see para_printf(). However, clang
131 * is not smart enough to prove this and complains nevertheless.
132 * Casting the return value to void silences clang.
133 */
134 (void)WRITE_STATUS_ITEM(&b, SI_FILE_SIZE, "%zu\n", nmmd->size / 1024);
135 (void)WRITE_STATUS_ITEM(&b, SI_MTIME, "%s\n", mtime);
136 (void)WRITE_STATUS_ITEM(&b, SI_STATUS, "%s\n", status);
137 (void)WRITE_STATUS_ITEM(&b, SI_STATUS_FLAGS, "%s\n", flags);
138 (void)WRITE_STATUS_ITEM(&b, SI_OFFSET, "%li\n", offset);
139 (void)WRITE_STATUS_ITEM(&b, SI_AFS_MODE, "%s\n", mmd->afs_mode_string);
140 (void)WRITE_STATUS_ITEM(&b, SI_STREAM_START, "%lu.%lu\n",
141 (long unsigned)nmmd->stream_start.tv_sec,
142 (long unsigned)nmmd->stream_start.tv_usec);
143 (void)WRITE_STATUS_ITEM(&b, SI_CURRENT_TIME, "%lu.%lu\n",
144 (long unsigned)current_time.tv_sec,
145 (long unsigned)current_time.tv_usec);
146 free(flags);
147 free(status);
148 free(ut);
149 *result = b.buf;
150 return b.offset;
151 }
152
153 static int check_sender_args(int argc, char * const * argv, struct sender_command_data *scd)
154 {
155 int i;
156 /* this has to match sender.h */
157 const char *subcmds[] = {"add", "delete", "allow", "deny", "on", "off", NULL};
158
159 scd->sender_num = -1;
160 if (argc < 2)
161 return -E_COMMAND_SYNTAX;
162 for (i = 0; senders[i].name; i++)
163 if (!strcmp(senders[i].name, argv[1]))
164 break;
165 PARA_DEBUG_LOG("%d:%s\n", argc, argv[1]);
166 if (!senders[i].name)
167 return -E_COMMAND_SYNTAX;
168 scd->sender_num = i;
169 for (i = 0; subcmds[i]; i++)
170 if (!strcmp(subcmds[i], argv[2]))
171 break;
172 if (!subcmds[i])
173 return -E_COMMAND_SYNTAX;
174 scd->cmd_num = i;
175 if (!senders[scd->sender_num].client_cmds[scd->cmd_num])
176 return -E_SENDER_CMD;
177 switch (scd->cmd_num) {
178 case SENDER_ON:
179 case SENDER_OFF:
180 if (argc != 3)
181 return -E_COMMAND_SYNTAX;
182 break;
183 case SENDER_DENY:
184 case SENDER_ALLOW:
185 if (argc != 4 || parse_cidr(argv[3], scd->host,
186 sizeof(scd->host), &scd->netmask) == NULL)
187 return -E_COMMAND_SYNTAX;
188 break;
189 case SENDER_ADD:
190 case SENDER_DELETE:
191 if (argc != 4)
192 return -E_COMMAND_SYNTAX;
193 return parse_fec_url(argv[3], scd);
194 default:
195 return -E_COMMAND_SYNTAX;
196 }
197 return 1;
198 }
199
200 /**
201 * Send a sideband packet through a blocking file descriptor.
202 *
203 * \param scc fd and crypto keys.
204 * \param buf The buffer to send.
205 * \param numbytes The size of \a buf.
206 * \param band The sideband designator of this packet.
207 * \param dont_free If true, never deallocate \a buf.
208 *
209 * The nonblock flag must be disabled for the file descriptor given by \a scc.
210 *
211 * Stream cipher encryption is automatically activated if neccessary via the
212 * sideband transformation, depending on the value of \a band.
213 *
214 * \return Standard.
215 *
216 * \sa \ref send_sb_va().
217 */
218 int send_sb(struct stream_cipher_context *scc, void *buf, size_t numbytes,
219 int band, bool dont_free)
220 {
221 int ret;
222 struct sb_context *sbc;
223 struct iovec iov[2];
224 struct sb_buffer sbb = SBB_INIT(band, buf, numbytes);
225 sb_transformation trafo = band < SBD_PROCEED? NULL : sc_trafo;
226
227 sbc = sb_new_send(&sbb, dont_free, trafo, scc->send);
228 do {
229 ret = sb_get_send_buffers(sbc, iov);
230 ret = xwritev(scc->fd, iov, ret);
231 if (ret < 0)
232 goto fail;
233 } while (sb_sent(sbc, ret) == false);
234 return 1;
235 fail:
236 sb_free(sbc);
237 return ret;
238 }
239
240 /**
241 * Create a variable sized buffer and send it as a sideband packet.
242 *
243 * \param scc Passed to \ref send_sb.
244 * \param band See \ref send_sb.
245 * \param fmt The format string.
246 *
247 * \return The return value of the underlying call to \ref send_sb.
248 */
249 __printf_3_4 int send_sb_va(struct stream_cipher_context *scc, int band,
250 const char *fmt, ...)
251 {
252 va_list ap;
253 char *msg;
254 int ret;
255
256 va_start(ap, fmt);
257 ret = xvasprintf(&msg, fmt, ap);
258 va_end(ap);
259 return send_sb(scc, msg, ret, band, false);
260 }
261
262 int send_strerror(struct command_context *cc, int err)
263 {
264 return cc->use_sideband?
265 send_sb_va(&cc->scc, SBD_ERROR_LOG, "%s\n", para_strerror(err))
266 :
267 sc_send_va_buffer(&cc->scc, "%s\n", para_strerror(err));
268 }
269
270 /**
271 * Send a sideband packet through a blocking file descriptor.
272 *
273 * \param scc fd and crypto keys.
274 * \param expected_band The expected band designator.
275 * \param max_size Passed to \ref sb_new_recv().
276 * \param result Body of the sideband packet is returned here.
277 *
278 * If \a expected_band is not \p SBD_ANY, the band designator of the received
279 * sideband packet is compared to \a expected_band and a mismatch is considered
280 * an error.
281 *
282 * \return Standard.
283 */
284 int recv_sb(struct stream_cipher_context *scc,
285 enum sb_designator expected_band,
286 size_t max_size, struct iovec *result)
287 {
288 int ret;
289 struct sb_context *sbc;
290 struct iovec iov;
291 struct sb_buffer sbb;
292 sb_transformation trafo;
293
294 trafo = expected_band != SBD_ANY && expected_band < SBD_PROCEED?
295 NULL : sc_trafo;
296 sbc = sb_new_recv(max_size, trafo, scc->recv);
297 for (;;) {
298 sb_get_recv_buffer(sbc, &iov);
299 ret = recv_bin_buffer(scc->fd, iov.iov_base, iov.iov_len);
300 if (ret == 0)
301 ret = -E_EOF;
302 if (ret < 0)
303 goto fail;
304 ret = sb_received(sbc, ret, &sbb);
305 if (ret < 0)
306 goto fail;
307 if (ret > 0)
308 break;
309 }
310 ret = -E_BAD_BAND;
311 if (expected_band != SBD_ANY && sbb.band != expected_band)
312 goto fail;
313 *result = sbb.iov;
314 return 1;
315 fail:
316 sb_free(sbc);
317 return ret;
318 }
319
320 int com_sender(struct command_context *cc)
321 {
322 int i, ret = 0;
323 char *msg = NULL;
324 struct sender_command_data scd;
325
326 if (cc->argc < 2) {
327 for (i = 0; senders[i].name; i++) {
328 char *tmp;
329 ret = xasprintf(&tmp, "%s%s\n", msg? msg : "",
330 senders[i].name);
331 free(msg);
332 msg = tmp;
333 }
334 if (cc->use_sideband)
335 return send_sb(&cc->scc, msg, ret, SBD_OUTPUT, false);
336 ret = sc_send_buffer(&cc->scc, msg);
337 free(msg);
338 return ret;
339 }
340 ret = check_sender_args(cc->argc, cc->argv, &scd);
341 if (ret < 0) {
342 if (scd.sender_num < 0)
343 return ret;
344 msg = senders[scd.sender_num].help();
345 if (cc->use_sideband)
346 return send_sb(&cc->scc, msg, strlen(msg), SBD_OUTPUT,
347 false);
348 ret = sc_send_buffer(&cc->scc, msg);
349 free(msg);
350 return ret;
351 }
352
353 switch (scd.cmd_num) {
354 case SENDER_ADD:
355 case SENDER_DELETE:
356 assert(senders[scd.sender_num].resolve_target);
357 ret = senders[scd.sender_num].resolve_target(cc->argv[3], &scd);
358 if (ret < 0)
359 return ret;
360 }
361
362 for (i = 0; i < 10; i++) {
363 mutex_lock(mmd_mutex);
364 if (mmd->sender_cmd_data.cmd_num >= 0) {
365 mutex_unlock(mmd_mutex);
366 usleep(100 * 1000);
367 continue;
368 }
369 memcpy(&mmd->sender_cmd_data, &scd, sizeof(scd));
370 mutex_unlock(mmd_mutex);
371 break;
372 }
373 return (i < 10)? 1 : -E_LOCK;
374 }
375
376 /* server info */
377 int com_si(struct command_context *cc)
378 {
379 int i, ret;
380 char *msg, *ut, *sender_info = NULL;
381
382 if (cc->argc != 1)
383 return -E_COMMAND_SYNTAX;
384 mutex_lock(mmd_mutex);
385 for (i = 0; senders[i].name; i++) {
386 char *info = senders[i].info();
387 sender_info = para_strcat(sender_info, info);
388 free(info);
389 }
390 ut = get_server_uptime_str(now);
391 ret = xasprintf(&msg, "version: " GIT_VERSION "\n"
392 "up: %s\nplayed: %u\n"
393 "server_pid: %d\n"
394 "afs_pid: %d\n"
395 "connections (active/accepted/total): %u/%u/%u\n"
396 "current loglevel: %s\n"
397 "supported audio formats: %s\n"
398 "%s",
399 ut, mmd->num_played,
400 (int)getppid(),
401 (int)mmd->afs_pid,
402 mmd->active_connections,
403 mmd->num_commands,
404 mmd->num_connects,
405 conf.loglevel_arg,
406 SERVER_AUDIO_FORMATS,
407 sender_info
408 );
409 mutex_unlock(mmd_mutex);
410 free(ut);
411 free(sender_info);
412 if (cc->use_sideband)
413 return send_sb(&cc->scc, msg, ret, SBD_OUTPUT, false);
414 ret = sc_send_bin_buffer(&cc->scc, msg, ret);
415 free(msg);
416 return ret;
417 }
418
419 /* version */
420 int com_version(struct command_context *cc)
421 {
422 char *msg;
423 size_t len;
424
425 if (cc->argc != 1)
426 return -E_COMMAND_SYNTAX;
427 msg = VERSION_TEXT("server") "built: " BUILD_DATE "\n" UNAME_RS
428 ", " CC_VERSION "\n";
429 len = strlen(msg);
430 if (cc->use_sideband)
431 return send_sb(&cc->scc, msg, len, SBD_OUTPUT, true);
432 return sc_send_bin_buffer(&cc->scc, msg, len);
433 }
434
435 #define EMPTY_STATUS_ITEMS \
436 ITEM(PATH) \
437 ITEM(DIRECTORY) \
438 ITEM(BASENAME) \
439 ITEM(SCORE) \
440 ITEM(ATTRIBUTES_BITMAP) \
441 ITEM(ATTRIBUTES_TXT) \
442 ITEM(HASH) \
443 ITEM(IMAGE_ID) \
444 ITEM(IMAGE_NAME) \
445 ITEM(LYRICS_ID) \
446 ITEM(LYRICS_NAME) \
447 ITEM(BITRATE) \
448 ITEM(FORMAT) \
449 ITEM(FREQUENCY) \
450 ITEM(CHANNELS) \
451 ITEM(DURATION) \
452 ITEM(SECONDS_TOTAL) \
453 ITEM(NUM_PLAYED) \
454 ITEM(LAST_PLAYED) \
455 ITEM(TECHINFO) \
456 ITEM(ARTIST) \
457 ITEM(TITLE) \
458 ITEM(YEAR) \
459 ITEM(ALBUM) \
460 ITEM(COMMENT) \
461 ITEM(AMPLIFICATION)
462
463 /**
464 * Write a list of audio-file related status items with empty values.
465 *
466 * This is used by vss when currently no audio file is open.
467 */
468 static unsigned empty_status_items(int parser_friendly, char **result)
469 {
470 static char *esi;
471 static unsigned len;
472
473 if (esi)
474 goto out;
475
476 if (parser_friendly)
477 len = xasprintf(&esi,
478 #define ITEM(x) "0004 %02x:\n"
479 EMPTY_STATUS_ITEMS
480 #undef ITEM
481 #define ITEM(x) , SI_ ## x
482 EMPTY_STATUS_ITEMS
483 #undef ITEM
484 );
485 else
486 len = xasprintf(&esi,
487 #define ITEM(x) "%s:\n"
488 EMPTY_STATUS_ITEMS
489 #undef ITEM
490 #define ITEM(x) ,status_item_list[SI_ ## x]
491 EMPTY_STATUS_ITEMS
492 #undef ITEM
493 );
494 out:
495 *result = esi;
496 return len;
497 }
498 #undef EMPTY_STATUS_ITEMS
499
500 /* stat */
501 int com_stat(struct command_context *cc)
502 {
503 int i, ret;
504 struct misc_meta_data tmp, *nmmd = &tmp;
505 char *s, *esi = NULL;
506 int32_t num = 0;
507 int parser_friendly = 0;
508
509 para_sigaction(SIGUSR1, dummy);
510
511 for (i = 1; i < cc->argc; i++) {
512 const char *arg = cc->argv[i];
513 if (arg[0] != '-')
514 break;
515 if (!strcmp(arg, "--")) {
516 i++;
517 break;
518 }
519 if (!strncmp(arg, "-n=", 3)) {
520 ret = para_atoi32(arg + 3, &num);
521 if (ret < 0)
522 return ret;
523 continue;
524 }
525 if (!strcmp(arg, "-p")) {
526 parser_friendly = 1;
527 continue;
528 }
529 return -E_COMMAND_SYNTAX;
530 }
531 if (i != cc->argc)
532 return -E_COMMAND_SYNTAX;
533 for (;;) {
534 mmd_dup(nmmd);
535 ret = get_status(nmmd, parser_friendly, &s);
536 if (cc->use_sideband)
537 ret = send_sb(&cc->scc, s, ret, SBD_OUTPUT, false);
538 else {
539 ret = sc_send_bin_buffer(&cc->scc, s, ret);
540 free(s);
541 }
542 if (ret < 0)
543 goto out;
544 if (nmmd->vss_status_flags & VSS_NEXT) {
545 ret = empty_status_items(parser_friendly, &esi);
546 if (cc->use_sideband)
547 ret = send_sb(&cc->scc, esi, ret, SBD_OUTPUT,
548 true);
549 else
550 ret = sc_send_bin_buffer(&cc->scc, esi, ret);
551 if (ret < 0)
552 goto out;
553 } else
554 send_afs_status(cc, parser_friendly);
555 ret = 1;
556 if (num > 0 && !--num)
557 goto out;
558 sleep(50);
559 ret = -E_SERVER_CRASH;
560 if (getppid() == 1)
561 goto out;
562 }
563 out:
564 free(esi);
565 return ret;
566 }
567
568 static int send_list_of_commands(struct command_context *cc, struct server_command *cmd,
569 const char *handler)
570 {
571 int ret;
572 char *msg = NULL;
573
574 for (; cmd->name; cmd++) {
575 char *tmp, *perms = cmd_perms_itohuman(cmd->perms);
576 tmp = make_message("%s\t%s\t%s\t%s\n", cmd->name, handler,
577 perms, cmd->description);
578 free(perms);
579 msg = para_strcat(msg, tmp);
580 free(tmp);
581 }
582 if (cc->use_sideband)
583 return send_sb(&cc->scc, msg, strlen(msg), SBD_OUTPUT, false);
584 ret = sc_send_buffer(&cc->scc, msg);
585 free(msg);
586 return ret;
587 }
588
589 /* returns string that must be freed by the caller */
590 static struct server_command *get_cmd_ptr(const char *name, char **handler)
591 {
592 struct server_command *cmd;
593
594 for (cmd = server_cmds; cmd->name; cmd++)
595 if (!strcmp(cmd->name, name)) {
596 if (handler)
597 *handler = para_strdup("server"); /* server commands */
598 return cmd;
599 }
600 /* not found, look for commands supported by afs */
601 for (cmd = afs_cmds; cmd->name; cmd++)
602 if (!strcmp(cmd->name, name)) {
603 if (handler)
604 *handler = para_strdup("afs");
605 return cmd;
606 }
607 return NULL;
608 }
609
610 /* help */
611 int com_help(struct command_context *cc)
612 {
613 struct server_command *cmd;
614 char *perms, *handler, *buf;
615 int ret;
616
617 if (cc->argc < 2) {
618 /* no argument given, print list of commands */
619 if ((ret = send_list_of_commands(cc, server_cmds, "server")) < 0)
620 return ret;
621 return send_list_of_commands(cc, afs_cmds, "afs");
622 }
623 /* argument given for help */
624 cmd = get_cmd_ptr(cc->argv[1], &handler);
625 if (!cmd)
626 return -E_BAD_CMD;
627 perms = cmd_perms_itohuman(cmd->perms);
628 ret = xasprintf(&buf, "%s - %s\n\n"
629 "handler: %s\n"
630 "permissions: %s\n"
631 "usage: %s\n\n"
632 "%s\n",
633 cc->argv[1],
634 cmd->description,
635 handler,
636 perms,
637 cmd->usage,
638 cmd->help
639 );
640 free(perms);
641 free(handler);
642 if (cc->use_sideband)
643 return send_sb(&cc->scc, buf, ret, SBD_OUTPUT, false);
644 ret = sc_send_buffer(&cc->scc, buf);
645 free(buf);
646 return ret;
647 }
648
649 /* hup */
650 int com_hup(struct command_context *cc)
651 {
652 if (cc->argc != 1)
653 return -E_COMMAND_SYNTAX;
654 kill(getppid(), SIGHUP);
655 return 1;
656 }
657
658 /* term */
659 int com_term(struct command_context *cc)
660 {
661 if (cc->argc != 1)
662 return -E_COMMAND_SYNTAX;
663 kill(getppid(), SIGTERM);
664 return 1;
665 }
666
667 int com_play(struct command_context *cc)
668 {
669 if (cc->argc != 1)
670 return -E_COMMAND_SYNTAX;
671 mutex_lock(mmd_mutex);
672 mmd->new_vss_status_flags |= VSS_PLAYING;
673 mmd->new_vss_status_flags &= ~VSS_NOMORE;
674 mutex_unlock(mmd_mutex);
675 return 1;
676 }
677
678 /* stop */
679 int com_stop(struct command_context *cc)
680 {
681 if (cc->argc != 1)
682 return -E_COMMAND_SYNTAX;
683 mutex_lock(mmd_mutex);
684 mmd->new_vss_status_flags &= ~VSS_PLAYING;
685 mmd->new_vss_status_flags &= ~VSS_REPOS;
686 mmd->new_vss_status_flags |= VSS_NEXT;
687 mutex_unlock(mmd_mutex);
688 return 1;
689 }
690
691 /* pause */
692 int com_pause(struct command_context *cc)
693 {
694 if (cc->argc != 1)
695 return -E_COMMAND_SYNTAX;
696 mutex_lock(mmd_mutex);
697 if (!vss_paused() && !vss_stopped()) {
698 mmd->events++;
699 mmd->new_vss_status_flags &= ~VSS_PLAYING;
700 mmd->new_vss_status_flags &= ~VSS_NEXT;
701 }
702 mutex_unlock(mmd_mutex);
703 return 1;
704 }
705
706 /* next */
707 int com_next(struct command_context *cc)
708 {
709 if (cc->argc != 1)
710 return -E_COMMAND_SYNTAX;
711 mutex_lock(mmd_mutex);
712 mmd->events++;
713 mmd->new_vss_status_flags |= VSS_NEXT;
714 mutex_unlock(mmd_mutex);
715 return 1;
716 }
717
718 /* nomore */
719 int com_nomore(struct command_context *cc)
720 {
721 if (cc->argc != 1)
722 return -E_COMMAND_SYNTAX;
723 mutex_lock(mmd_mutex);
724 if (vss_playing() || vss_paused())
725 mmd->new_vss_status_flags |= VSS_NOMORE;
726 mutex_unlock(mmd_mutex);
727 return 1;
728 }
729
730 /* ff */
731 int com_ff(struct command_context *cc)
732 {
733 long promille;
734 int ret, backwards = 0;
735 unsigned i;
736 char c;
737
738 if (cc->argc != 2)
739 return -E_COMMAND_SYNTAX;
740 if (!(ret = sscanf(cc->argv[1], "%u%c", &i, &c)))
741 return -E_COMMAND_SYNTAX;
742 if (ret > 1 && c == '-')
743 backwards = 1; /* jmp backwards */
744 mutex_lock(mmd_mutex);
745 ret = -E_NO_AUDIO_FILE;
746 if (!mmd->afd.afhi.chunks_total || !mmd->afd.afhi.seconds_total)
747 goto out;
748 promille = (1000 * mmd->current_chunk) / mmd->afd.afhi.chunks_total;
749 if (backwards)
750 promille -= 1000 * i / mmd->afd.afhi.seconds_total;
751 else
752 promille += 1000 * i / mmd->afd.afhi.seconds_total;
753 if (promille < 0)
754 promille = 0;
755 if (promille > 1000) {
756 mmd->new_vss_status_flags |= VSS_NEXT;
757 goto out;
758 }
759 mmd->repos_request = (mmd->afd.afhi.chunks_total * promille) / 1000;
760 mmd->new_vss_status_flags |= VSS_REPOS;
761 mmd->new_vss_status_flags &= ~VSS_NEXT;
762 mmd->events++;
763 ret = 1;
764 out:
765 mutex_unlock(mmd_mutex);
766 return ret;
767 }
768
769 /* jmp */
770 int com_jmp(struct command_context *cc)
771 {
772 long unsigned int i;
773 int ret;
774
775 if (cc->argc != 2)
776 return -E_COMMAND_SYNTAX;
777 if (sscanf(cc->argv[1], "%lu", &i) <= 0)
778 return -E_COMMAND_SYNTAX;
779 mutex_lock(mmd_mutex);
780 ret = -E_NO_AUDIO_FILE;
781 if (!mmd->afd.afhi.chunks_total)
782 goto out;
783 if (i > 100)
784 i = 100;
785 PARA_INFO_LOG("jumping to %lu%%\n", i);
786 mmd->repos_request = (mmd->afd.afhi.chunks_total * i + 50)/ 100;
787 PARA_INFO_LOG("sent: %lu, offset before jmp: %lu\n",
788 mmd->chunks_sent, mmd->offset);
789 mmd->new_vss_status_flags |= VSS_REPOS;
790 mmd->new_vss_status_flags &= ~VSS_NEXT;
791 ret = 1;
792 mmd->events++;
793 out:
794 mutex_unlock(mmd_mutex);
795 return ret;
796 }
797
798 /*
799 * check if perms are sufficient to exec a command having perms cmd_perms.
800 * Returns 0 if perms are sufficient, -E_PERM otherwise.
801 */
802 static int check_perms(unsigned int perms, struct server_command *cmd_ptr)
803 {
804 PARA_DEBUG_LOG("checking permissions\n");
805 return (cmd_ptr->perms & perms) < cmd_ptr->perms ? -E_PERM : 0;
806 }
807
808 /*
809 * Parse first string from *cmd and lookup in table of valid commands.
810 * On error, NULL is returned.
811 */
812 static struct server_command *parse_cmd(const char *cmdstr)
813 {
814 char buf[255];
815 int n = 0;
816
817 sscanf(cmdstr, "%200s%n", buf, &n);
818 if (!n)
819 return NULL;
820 buf[n] = '\0';
821 return get_cmd_ptr(buf, NULL);
822 }
823
824 static int read_command(struct stream_cipher_context *scc, char **result)
825 {
826 int ret;
827 char buf[4096];
828 char *command = NULL;
829
830 for (;;) {
831 size_t numbytes;
832 char *p;
833
834 ret = sc_recv_buffer(scc, buf, sizeof(buf));
835 if (ret < 0)
836 goto out;
837 if (!ret)
838 break;
839 numbytes = ret;
840 ret = -E_COMMAND_SYNTAX;
841 if (command && numbytes + strlen(command) > MAX_COMMAND_LEN) /* DOS */
842 goto out;
843 command = para_strcat(command, buf);
844 p = strstr(command, EOC_MSG);
845 if (p) {
846 *p = '\0';
847 break;
848 }
849 }
850 ret = command? 1 : -E_COMMAND_SYNTAX;
851 out:
852 if (ret < 0)
853 free(command);
854 else
855 *result = command;
856 return ret;
857
858 }
859
860 static void reset_signals(void)
861 {
862 para_sigaction(SIGCHLD, SIG_IGN);
863 para_sigaction(SIGINT, SIG_DFL);
864 para_sigaction(SIGTERM, SIG_DFL);
865 para_sigaction(SIGHUP, SIG_DFL);
866 }
867
868 static int parse_auth_request(char *buf, int len, struct user **u,
869 bool *use_sideband)
870 {
871 int ret;
872 char *p, *username, **features = NULL;
873 size_t auth_rq_len = strlen(AUTH_REQUEST_MSG);
874
875 *u = NULL;
876 *use_sideband = false;
877 if (len < auth_rq_len + 2)
878 return -E_AUTH_REQUEST;
879 if (strncmp(buf, AUTH_REQUEST_MSG, auth_rq_len) != 0)
880 return -E_AUTH_REQUEST;
881 username = buf + auth_rq_len;
882 p = strchr(username, ' ');
883 if (p) {
884 int i;
885 if (p == username)
886 return -E_AUTH_REQUEST;
887 *p = '\0';
888 p++;
889 create_argv(p, ",", &features);
890 for (i = 0; features[i]; i++) {
891 if (strcmp(features[i], "sideband") == 0)
892 *use_sideband = true;
893 else {
894 ret = -E_BAD_FEATURE;
895 goto out;
896 }
897 }
898 }
899 PARA_DEBUG_LOG("received auth request for user %s (sideband = %s)\n",
900 username, *use_sideband? "true" : "false");
901 *u = lookup_user(username);
902 ret = 1;
903 out:
904 free_argv(features);
905 return ret;
906 }
907
908 #define HANDSHAKE_BUFSIZE 4096
909
910 static int parse_sb_command(struct command_context *cc, struct iovec *iov)
911 {
912 int ret, i;
913 char *p, *end;
914
915 ret = -E_BAD_CMD;
916 if (iov->iov_base == NULL || iov->iov_len == 0)
917 goto out;
918 p = iov->iov_base;
919 p[iov->iov_len - 1] = '\0'; /* just to be sure */
920 cc->cmd = get_cmd_ptr(p, NULL);
921 if (!cc->cmd)
922 goto out;
923 ret = check_perms(cc->u->perms, cc->cmd);
924 if (ret < 0)
925 goto out;
926 end = iov->iov_base + iov->iov_len;
927 for (i = 0, p = iov->iov_base; p < end; i++)
928 p += strlen(p) + 1;
929 cc->argc = i;
930 cc->argv = para_malloc((cc->argc + 1) * sizeof(char *));
931 for (i = 0, p = iov->iov_base; p < end; i++) {
932 cc->argv[i] = para_strdup(p);
933 p += strlen(p) + 1;
934 }
935 cc->argv[cc->argc] = NULL;
936 ret = cc->argc;
937 out:
938 free(iov->iov_base);
939 return ret;
940 }
941
942 /**
943 * Perform user authentication and execute a command.
944 *
945 * \param fd The file descriptor to send output to.
946 * \param peername Identifies the connecting peer.
947 *
948 * Whenever para_server accepts an incoming tcp connection on
949 * the port it listens on, it forks and the resulting child
950 * calls this function.
951 *
952 * An RSA-based challenge/response is used to authenticate
953 * the peer. It that authentication succeeds, a random
954 * session key is generated and sent back to the peer,
955 * encrypted with its RSA public key. From this point on,
956 * all transfers are crypted with this session key.
957 *
958 * Next it is checked if the peer supplied a valid server command or a command
959 * for the audio file selector. If yes, and if the user has sufficient
960 * permissions to execute that command, the function calls the corresponding
961 * command handler which does argument checking and further processing.
962 *
963 * In order to cope with a DOS attacks, a timeout is set up
964 * which terminates the function if the connection was not
965 * authenticated when the timeout expires.
966 *
967 * \sa alarm(2), crypt.c, crypt.h
968 */
969 __noreturn void handle_connect(int fd, const char *peername)
970 {
971 int ret;
972 unsigned char rand_buf[CHALLENGE_SIZE + 2 * SESSION_KEY_LEN];
973 unsigned char challenge_hash[HASH_SIZE];
974 char *p, *command = NULL, *buf = para_malloc(HANDSHAKE_BUFSIZE) /* must be on the heap */;
975 size_t numbytes;
976 struct command_context cc_struct = {.peer = peername}, *cc = &cc_struct;
977
978 cc->scc.fd = fd;
979 reset_signals();
980 /* we need a blocking fd here as recv() might return EAGAIN otherwise. */
981 ret = mark_fd_blocking(fd);
982 if (ret < 0)
983 goto net_err;
984 /* send Welcome message */
985 ret = write_va_buffer(fd, "This is para_server, version "
986 PACKAGE_VERSION ".\n"
987 "Features: sideband,foo\n"
988 );
989 if (ret < 0)
990 goto net_err;
991 /* recv auth request line */
992 ret = recv_buffer(fd, buf, HANDSHAKE_BUFSIZE);
993 if (ret < 0)
994 goto net_err;
995 ret = parse_auth_request(buf, ret, &cc->u, &cc->use_sideband);
996 if (ret < 0)
997 goto net_err;
998 p = buf + strlen(AUTH_REQUEST_MSG);
999 PARA_DEBUG_LOG("received auth request for user %s\n", p);
1000 cc->u = lookup_user(p);
1001 if (cc->u) {
1002 get_random_bytes_or_die(rand_buf, sizeof(rand_buf));
1003 ret = pub_encrypt(cc->u->pubkey, rand_buf, sizeof(rand_buf),
1004 (unsigned char *)buf);
1005 if (ret < 0)
1006 goto net_err;
1007 numbytes = ret;
1008 } else {
1009 /*
1010 * We don't want to reveal our user names, so we send a
1011 * challenge to the client even if the user does not exist, and
1012 * fail the authentication later.
1013 */
1014 numbytes = 256;
1015 get_random_bytes_or_die((unsigned char *)buf, numbytes);
1016 }
1017 PARA_DEBUG_LOG("sending %u byte challenge + rc4 keys (%zu bytes)\n",
1018 CHALLENGE_SIZE, numbytes);
1019 if (cc->use_sideband) {
1020 struct iovec iov;
1021 ret = send_sb(&cc->scc, buf, numbytes, SBD_CHALLENGE, false);
1022 buf = NULL;
1023 if (ret < 0)
1024 goto net_err;
1025 ret = recv_sb(&cc->scc, SBD_CHALLENGE_RESPONSE,
1026 HANDSHAKE_BUFSIZE, &iov);
1027 if (ret < 0)
1028 goto net_err;
1029 buf = iov.iov_base;
1030 numbytes = iov.iov_len;
1031 } else {
1032 ret = write_all(fd, buf, numbytes);
1033 if (ret < 0)
1034 goto net_err;
1035 /* recv challenge response */
1036 ret = recv_bin_buffer(fd, buf, HASH_SIZE);
1037 if (ret < 0)
1038 goto net_err;
1039 numbytes = ret;
1040 }
1041 PARA_DEBUG_LOG("received %zu bytes challenge response\n", numbytes);
1042 ret = -E_BAD_USER;
1043 if (!cc->u)
1044 goto net_err;
1045 /*
1046 * The correct response is the hash of the first CHALLENGE_SIZE bytes
1047 * of the random data.
1048 */
1049 ret = -E_BAD_AUTH;
1050 if (numbytes != HASH_SIZE)
1051 goto net_err;
1052 hash_function((char *)rand_buf, CHALLENGE_SIZE, challenge_hash);
1053 if (memcmp(challenge_hash, buf, HASH_SIZE))
1054 goto net_err;
1055 /* auth successful */
1056 alarm(0);
1057 PARA_INFO_LOG("good auth for %s\n", cc->u->name);
1058 /* init stream cipher keys with the second part of the random buffer */
1059 cc->scc.recv = sc_new(rand_buf + CHALLENGE_SIZE, SESSION_KEY_LEN);
1060 cc->scc.send = sc_new(rand_buf + CHALLENGE_SIZE + SESSION_KEY_LEN, SESSION_KEY_LEN);
1061 if (cc->use_sideband)
1062 ret = send_sb(&cc->scc, NULL, 0, SBD_PROCEED, false);
1063 else
1064 ret = sc_send_buffer(&cc->scc, PROCEED_MSG);
1065 if (ret < 0)
1066 goto net_err;
1067 if (cc->use_sideband) {
1068 struct iovec iov;
1069 ret = recv_sb(&cc->scc, SBD_COMMAND, MAX_COMMAND_LEN, &iov);
1070 if (ret < 0)
1071 goto net_err;
1072 ret = parse_sb_command(cc, &iov);
1073 if (ret < 0)
1074 goto err_out;
1075 cc->argc = ret;
1076 } else {
1077 ret = read_command(&cc->scc, &command);
1078 if (ret == -E_COMMAND_SYNTAX)
1079 goto err_out;
1080 if (ret < 0)
1081 goto net_err;
1082 ret = -E_BAD_CMD;
1083 cc->cmd = parse_cmd(command);
1084 if (!cc->cmd)
1085 goto err_out;
1086 /* valid command, check permissions */
1087 ret = check_perms(cc->u->perms, cc->cmd);
1088 if (ret < 0)
1089 goto err_out;
1090 /* valid command and sufficient perms */
1091 ret = create_argv(command, "\n", &cc->argv);
1092 if (ret < 0)
1093 goto err_out;
1094 cc->argc = ret;
1095 }
1096 PARA_NOTICE_LOG("calling com_%s() for %s@%s\n", cc->cmd->name,
1097 cc->u->name, peername);
1098 ret = cc->cmd->handler(cc);
1099 free_argv(cc->argv);
1100 mutex_lock(mmd_mutex);
1101 mmd->num_commands++;
1102 mutex_unlock(mmd_mutex);
1103 if (ret >= 0)
1104 goto out;
1105 err_out:
1106 if (send_strerror(cc, -ret) >= 0 && cc->use_sideband)
1107 send_sb(&cc->scc, NULL, 0, SBD_EXIT__FAILURE, true);
1108 net_err:
1109 PARA_NOTICE_LOG("%s\n", para_strerror(-ret));
1110 out:
1111 free(buf);
1112 free(command);
1113 mutex_lock(mmd_mutex);
1114 if (cc->cmd && (cc->cmd->perms & AFS_WRITE) && ret >= 0)
1115 mmd->events++;
1116 mmd->active_connections--;
1117 mutex_unlock(mmd_mutex);
1118 if (ret >= 0 && cc->use_sideband) {
1119 ret = send_sb(&cc->scc, NULL, 0, SBD_EXIT__SUCCESS, true);
1120 if (ret < 0)
1121 PARA_NOTICE_LOG("%s\n", para_strerror(-ret));
1122 }
1123 sc_free(cc->scc.recv);
1124 sc_free(cc->scc.send);
1125 exit(ret < 0? EXIT_FAILURE : EXIT_SUCCESS);
1126 }