92002c340e62c0593bc2b534193d8fecb1ea997b
[paraslash.git] / command.c
1 /*
2 * Copyright (C) 1997-2014 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 <netinet/in.h>
10 #include <sys/socket.h>
11 #include <regex.h>
12 #include <signal.h>
13 #include <sys/types.h>
14 #include <osl.h>
15 #include <arpa/inet.h>
16 #include <sys/un.h>
17 #include <netdb.h>
18
19 #include "para.h"
20 #include "error.h"
21 #include "crypt.h"
22 #include "sideband.h"
23 #include "command.h"
24 #include "server.cmdline.h"
25 #include "string.h"
26 #include "afh.h"
27 #include "afs.h"
28 #include "server.h"
29 #include "list.h"
30 #include "send.h"
31 #include "sched.h"
32 #include "vss.h"
33 #include "net.h"
34 #include "daemon.h"
35 #include "fd.h"
36 #include "ipc.h"
37 #include "user_list.h"
38 #include "server_command_list.h"
39 #include "afs_command_list.h"
40 #include "signal.h"
41 #include "version.h"
42
43 static struct server_command afs_cmds[] = {DEFINE_AFS_CMD_ARRAY};
44 static struct server_command server_cmds[] = {DEFINE_SERVER_CMD_ARRAY};
45
46 /** Commands including options must be shorter than this. */
47 #define MAX_COMMAND_LEN 32768
48
49 extern int mmd_mutex;
50 extern struct misc_meta_data *mmd;
51 extern struct sender senders[];
52 int send_afs_status(struct command_context *cc, int parser_friendly);
53
54 static void dummy(__a_unused int s)
55 {
56 }
57
58 static void mmd_dup(struct misc_meta_data *new_mmd)
59 {
60 mutex_lock(mmd_mutex);
61 *new_mmd = *mmd;
62 mutex_unlock(mmd_mutex);
63 }
64
65 /*
66 * Compute human readable string containing vss status for given integer value.
67 *
68 * We don't want to use vss_playing() and friends here because we take a
69 * snapshot of the mmd struct and use the copy for computing the state of the
70 * vss. If the real data were used, we would take the mmd lock for a rather
71 * long time or risk to get an inconsistent view.
72 */
73 static char *vss_status_tohuman(unsigned int flags)
74 {
75 if (flags & VSS_PLAYING)
76 return para_strdup("playing");
77 if (flags & VSS_NEXT)
78 return para_strdup("stopped");
79 return para_strdup("paused");
80 }
81
82 /*
83 * return human readable permission string. Never returns NULL.
84 */
85 static char *cmd_perms_itohuman(unsigned int perms)
86 {
87 char *msg = para_malloc(5 * sizeof(char));
88
89 msg[0] = perms & AFS_READ? 'a' : '-';
90 msg[1] = perms & AFS_WRITE? 'A' : '-';
91 msg[2] = perms & VSS_READ? 'v' : '-';
92 msg[3] = perms & VSS_WRITE? 'V' : '-';
93 msg[4] = '\0';
94 return msg;
95 }
96
97 /*
98 * Never returns NULL.
99 */
100 static char *vss_get_status_flags(unsigned int flags)
101 {
102 char *msg = para_malloc(5 * sizeof(char));
103
104 msg[0] = (flags & VSS_PLAYING)? 'P' : '_';
105 msg[1] = (flags & VSS_NOMORE)? 'O' : '_';
106 msg[2] = (flags & VSS_NEXT)? 'N' : '_';
107 msg[3] = (flags & VSS_REPOS)? 'R' : '_';
108 msg[4] = '\0';
109 return msg;
110 }
111
112 static unsigned get_status(struct misc_meta_data *nmmd, int parser_friendly,
113 char **result)
114 {
115 char mtime[30] = "";
116 char *status, *flags; /* vss status info */
117 /* nobody updates our version of "now" */
118 long offset = (nmmd->offset + 500) / 1000;
119 struct timeval current_time;
120 struct tm mtime_tm;
121 struct para_buffer b = {.flags = parser_friendly? PBF_SIZE_PREFIX : 0};
122
123 /* report real status */
124 status = vss_status_tohuman(nmmd->vss_status_flags);
125 flags = vss_get_status_flags(nmmd->vss_status_flags);
126 if (nmmd->size) { /* parent currently has an audio file open */
127 localtime_r(&nmmd->mtime, &mtime_tm);
128 strftime(mtime, 29, "%b %d %Y", &mtime_tm);
129 }
130 clock_get_realtime(&current_time);
131 /*
132 * The calls to WRITE_STATUS_ITEM() below never fail because
133 * b->max_size is zero (unlimited), see para_printf(). However, clang
134 * is not smart enough to prove this and complains nevertheless.
135 * Casting the return value to void silences clang.
136 */
137 (void)WRITE_STATUS_ITEM(&b, SI_FILE_SIZE, "%zu\n", nmmd->size / 1024);
138 (void)WRITE_STATUS_ITEM(&b, SI_MTIME, "%s\n", mtime);
139 (void)WRITE_STATUS_ITEM(&b, SI_STATUS, "%s\n", status);
140 (void)WRITE_STATUS_ITEM(&b, SI_STATUS_FLAGS, "%s\n", flags);
141 (void)WRITE_STATUS_ITEM(&b, SI_OFFSET, "%li\n", offset);
142 (void)WRITE_STATUS_ITEM(&b, SI_AFS_MODE, "%s\n", mmd->afs_mode_string);
143 (void)WRITE_STATUS_ITEM(&b, SI_STREAM_START, "%lu.%lu\n",
144 (long unsigned)nmmd->stream_start.tv_sec,
145 (long unsigned)nmmd->stream_start.tv_usec);
146 (void)WRITE_STATUS_ITEM(&b, SI_CURRENT_TIME, "%lu.%lu\n",
147 (long unsigned)current_time.tv_sec,
148 (long unsigned)current_time.tv_usec);
149 free(flags);
150 free(status);
151 *result = b.buf;
152 return b.offset;
153 }
154
155 static int check_sender_args(int argc, char * const * argv, struct sender_command_data *scd)
156 {
157 int i;
158 /* this has to match sender.h */
159 const char *subcmds[] = {"add", "delete", "allow", "deny", "on", "off", NULL};
160
161 scd->sender_num = -1;
162 if (argc < 2)
163 return -E_COMMAND_SYNTAX;
164 for (i = 0; senders[i].name; i++)
165 if (!strcmp(senders[i].name, argv[1]))
166 break;
167 PARA_DEBUG_LOG("%d:%s\n", argc, argv[1]);
168 if (!senders[i].name)
169 return -E_COMMAND_SYNTAX;
170 scd->sender_num = i;
171 for (i = 0; subcmds[i]; i++)
172 if (!strcmp(subcmds[i], argv[2]))
173 break;
174 if (!subcmds[i])
175 return -E_COMMAND_SYNTAX;
176 scd->cmd_num = i;
177 if (!senders[scd->sender_num].client_cmds[scd->cmd_num])
178 return -E_SENDER_CMD;
179 switch (scd->cmd_num) {
180 case SENDER_ON:
181 case SENDER_OFF:
182 if (argc != 3)
183 return -E_COMMAND_SYNTAX;
184 break;
185 case SENDER_DENY:
186 case SENDER_ALLOW:
187 if (argc != 4 || parse_cidr(argv[3], scd->host,
188 sizeof(scd->host), &scd->netmask) == NULL)
189 return -E_COMMAND_SYNTAX;
190 break;
191 case SENDER_ADD:
192 case SENDER_DELETE:
193 if (argc != 4)
194 return -E_COMMAND_SYNTAX;
195 return parse_fec_url(argv[3], scd);
196 default:
197 return -E_COMMAND_SYNTAX;
198 }
199 return 1;
200 }
201
202 /**
203 * Send a sideband packet through a blocking file descriptor.
204 *
205 * \param scc fd and crypto keys.
206 * \param buf The buffer to send.
207 * \param numbytes The size of \a buf.
208 * \param band The sideband designator of this packet.
209 * \param dont_free If true, never deallocate \a buf.
210 *
211 * The nonblock flag must be disabled for the file descriptor given by \a scc.
212 *
213 * Stream cipher encryption is automatically activated if neccessary via the
214 * sideband transformation, depending on the value of \a band.
215 *
216 * \return Standard.
217 *
218 * \sa \ref send_sb_va().
219 */
220 int send_sb(struct stream_cipher_context *scc, void *buf, size_t numbytes,
221 int band, bool dont_free)
222 {
223 int ret;
224 struct sb_context *sbc;
225 struct iovec iov[2];
226 sb_transformation trafo = band < SBD_PROCEED? NULL : sc_trafo;
227 struct sb_buffer sbb = SBB_INIT(band, buf, numbytes);
228
229 sbc = sb_new_send(&sbb, dont_free, trafo, scc->send);
230 do {
231 ret = sb_get_send_buffers(sbc, iov);
232 ret = xwritev(scc->fd, iov, ret);
233 if (ret < 0)
234 goto fail;
235 } while (sb_sent(sbc, ret) == false);
236 return 1;
237 fail:
238 sb_free(sbc);
239 return ret;
240 }
241
242 /**
243 * Create a variable sized buffer and send it as a sideband packet.
244 *
245 * \param scc Passed to \ref send_sb.
246 * \param band See \ref send_sb.
247 * \param fmt The format string.
248 *
249 * \return The return value of the underlying call to \ref send_sb.
250 */
251 __printf_3_4 int send_sb_va(struct stream_cipher_context *scc, int band,
252 const char *fmt, ...)
253 {
254 va_list ap;
255 char *msg;
256 int ret;
257
258 va_start(ap, fmt);
259 ret = xvasprintf(&msg, fmt, ap);
260 va_end(ap);
261 return send_sb(scc, msg, ret, band, false);
262 }
263
264 /**
265 * Send an error message to a client.
266 *
267 * \param cc Client info.
268 * \param err The (positive) error code.
269 *
270 * \return The return value of the underlying call to send_sb_va().
271 */
272 int send_strerror(struct command_context *cc, int err)
273 {
274 return send_sb_va(&cc->scc, SBD_ERROR_LOG, "%s\n", para_strerror(err));
275 }
276
277 /**
278 * Send a sideband packet through a blocking file descriptor.
279 *
280 * \param scc fd and crypto keys.
281 * \param expected_band The expected band designator.
282 * \param max_size Passed to \ref sb_new_recv().
283 * \param result Body of the sideband packet is returned here.
284 *
285 * If \a expected_band is not \p SBD_ANY, the band designator of the received
286 * sideband packet is compared to \a expected_band and a mismatch is considered
287 * an error.
288 *
289 * \return Standard.
290 */
291 int recv_sb(struct stream_cipher_context *scc,
292 enum sb_designator expected_band,
293 size_t max_size, struct iovec *result)
294 {
295 int ret;
296 struct sb_context *sbc;
297 struct iovec iov;
298 struct sb_buffer sbb;
299 sb_transformation trafo;
300
301 trafo = expected_band != SBD_ANY && expected_band < SBD_PROCEED?
302 NULL : sc_trafo;
303 sbc = sb_new_recv(max_size, trafo, scc->recv);
304 for (;;) {
305 sb_get_recv_buffer(sbc, &iov);
306 ret = recv_bin_buffer(scc->fd, iov.iov_base, iov.iov_len);
307 if (ret == 0)
308 ret = -E_EOF;
309 if (ret < 0)
310 goto fail;
311 ret = sb_received(sbc, ret, &sbb);
312 if (ret < 0)
313 goto fail;
314 if (ret > 0)
315 break;
316 }
317 ret = -E_BAD_BAND;
318 if (expected_band != SBD_ANY && sbb.band != expected_band)
319 goto fail;
320 *result = sbb.iov;
321 return 1;
322 fail:
323 sb_free(sbc);
324 return ret;
325 }
326
327 static int com_sender(struct command_context *cc)
328 {
329 int i, ret = 0;
330 char *msg = NULL;
331 struct sender_command_data scd;
332
333 if (cc->argc < 2) {
334 for (i = 0; senders[i].name; i++) {
335 char *tmp;
336 ret = xasprintf(&tmp, "%s%s\n", msg? msg : "",
337 senders[i].name);
338 free(msg);
339 msg = tmp;
340 }
341 return send_sb(&cc->scc, msg, ret, SBD_OUTPUT, false);
342 }
343 ret = check_sender_args(cc->argc, cc->argv, &scd);
344 if (ret < 0) {
345 if (scd.sender_num < 0)
346 return ret;
347 msg = senders[scd.sender_num].help();
348 return send_sb(&cc->scc, msg, strlen(msg), SBD_OUTPUT, false);
349 }
350
351 switch (scd.cmd_num) {
352 case SENDER_ADD:
353 case SENDER_DELETE:
354 assert(senders[scd.sender_num].resolve_target);
355 ret = senders[scd.sender_num].resolve_target(cc->argv[3], &scd);
356 if (ret < 0)
357 return ret;
358 }
359
360 for (i = 0; i < 10; i++) {
361 mutex_lock(mmd_mutex);
362 if (mmd->sender_cmd_data.cmd_num >= 0) {
363 mutex_unlock(mmd_mutex);
364 usleep(100 * 1000);
365 continue;
366 }
367 mmd->sender_cmd_data = scd;
368 mutex_unlock(mmd_mutex);
369 break;
370 }
371 return (i < 10)? 1 : -E_LOCK;
372 }
373
374 /* server info */
375 static int com_si(struct command_context *cc)
376 {
377 int i, ret;
378 char *msg, *ut, *sender_info = NULL;
379
380 if (cc->argc != 1)
381 return -E_COMMAND_SYNTAX;
382 mutex_lock(mmd_mutex);
383 for (i = 0; senders[i].name; i++) {
384 char *info = senders[i].info();
385 sender_info = para_strcat(sender_info, info);
386 free(info);
387 }
388 ut = get_server_uptime_str(now);
389 ret = xasprintf(&msg,
390 "up: %s\nplayed: %u\n"
391 "server_pid: %d\n"
392 "afs_pid: %d\n"
393 "connections (active/accepted/total): %u/%u/%u\n"
394 "current loglevel: %s\n"
395 "supported audio formats: %s\n"
396 "%s",
397 ut, mmd->num_played,
398 (int)getppid(),
399 (int)mmd->afs_pid,
400 mmd->active_connections,
401 mmd->num_commands,
402 mmd->num_connects,
403 conf.loglevel_arg,
404 AUDIO_FORMAT_HANDLERS,
405 sender_info
406 );
407 mutex_unlock(mmd_mutex);
408 free(ut);
409 free(sender_info);
410 return send_sb(&cc->scc, msg, ret, SBD_OUTPUT, false);
411 }
412
413 /* version */
414 static int com_version(struct command_context *cc)
415 {
416 char *msg;
417 size_t len;
418
419 if (cc->argc != 1)
420 return -E_COMMAND_SYNTAX;
421 len = xasprintf(&msg, "%s", version_text("server"));
422 return send_sb(&cc->scc, msg, len, SBD_OUTPUT, false);
423 }
424
425 #define EMPTY_STATUS_ITEMS \
426 ITEM(PATH) \
427 ITEM(DIRECTORY) \
428 ITEM(BASENAME) \
429 ITEM(SCORE) \
430 ITEM(ATTRIBUTES_BITMAP) \
431 ITEM(ATTRIBUTES_TXT) \
432 ITEM(HASH) \
433 ITEM(IMAGE_ID) \
434 ITEM(IMAGE_NAME) \
435 ITEM(LYRICS_ID) \
436 ITEM(LYRICS_NAME) \
437 ITEM(BITRATE) \
438 ITEM(FORMAT) \
439 ITEM(FREQUENCY) \
440 ITEM(CHANNELS) \
441 ITEM(DURATION) \
442 ITEM(SECONDS_TOTAL) \
443 ITEM(NUM_PLAYED) \
444 ITEM(LAST_PLAYED) \
445 ITEM(TECHINFO) \
446 ITEM(ARTIST) \
447 ITEM(TITLE) \
448 ITEM(YEAR) \
449 ITEM(ALBUM) \
450 ITEM(COMMENT) \
451 ITEM(AMPLIFICATION)
452
453 /**
454 * Write a list of audio-file related status items with empty values.
455 *
456 * This is used by vss when currently no audio file is open.
457 */
458 static unsigned empty_status_items(int parser_friendly, char **result)
459 {
460 char *esi;
461 unsigned len;
462
463 if (parser_friendly)
464 len = xasprintf(&esi,
465 #define ITEM(x) "0004 %02x:\n"
466 EMPTY_STATUS_ITEMS
467 #undef ITEM
468 #define ITEM(x) , SI_ ## x
469 EMPTY_STATUS_ITEMS
470 #undef ITEM
471 );
472 else
473 len = xasprintf(&esi,
474 #define ITEM(x) "%s:\n"
475 EMPTY_STATUS_ITEMS
476 #undef ITEM
477 #define ITEM(x) ,status_item_list[SI_ ## x]
478 EMPTY_STATUS_ITEMS
479 #undef ITEM
480 );
481 *result = esi;
482 return len;
483 }
484 #undef EMPTY_STATUS_ITEMS
485
486 /* stat */
487 static int com_stat(struct command_context *cc)
488 {
489 int i, ret;
490 struct misc_meta_data tmp, *nmmd = &tmp;
491 char *s;
492 int32_t num = 0;
493 int parser_friendly = 0;
494
495 para_sigaction(SIGUSR1, dummy);
496
497 for (i = 1; i < cc->argc; i++) {
498 const char *arg = cc->argv[i];
499 if (arg[0] != '-')
500 break;
501 if (!strcmp(arg, "--")) {
502 i++;
503 break;
504 }
505 if (!strncmp(arg, "-n=", 3)) {
506 ret = para_atoi32(arg + 3, &num);
507 if (ret < 0)
508 return ret;
509 continue;
510 }
511 if (!strcmp(arg, "-p")) {
512 parser_friendly = 1;
513 continue;
514 }
515 return -E_COMMAND_SYNTAX;
516 }
517 if (i != cc->argc)
518 return -E_COMMAND_SYNTAX;
519 for (;;) {
520 mmd_dup(nmmd);
521 ret = get_status(nmmd, parser_friendly, &s);
522 ret = send_sb(&cc->scc, s, ret, SBD_OUTPUT, false);
523 if (ret < 0)
524 goto out;
525 if (nmmd->vss_status_flags & VSS_NEXT) {
526 char *esi;
527 ret = empty_status_items(parser_friendly, &esi);
528 ret = send_sb(&cc->scc, esi, ret, SBD_OUTPUT, false);
529 if (ret < 0)
530 goto out;
531 } else
532 send_afs_status(cc, parser_friendly);
533 ret = 1;
534 if (num > 0 && !--num)
535 goto out;
536 sleep(50);
537 ret = -E_SERVER_CRASH;
538 if (getppid() == 1)
539 goto out;
540 }
541 out:
542 return ret;
543 }
544
545 static int send_list_of_commands(struct command_context *cc, struct server_command *cmd,
546 const char *handler)
547 {
548 char *msg = NULL;
549
550 for (; cmd->name; cmd++) {
551 char *tmp, *perms = cmd_perms_itohuman(cmd->perms);
552 tmp = make_message("%s\t%s\t%s\t%s\n", cmd->name, handler,
553 perms, cmd->description);
554 free(perms);
555 msg = para_strcat(msg, tmp);
556 free(tmp);
557 }
558 assert(msg);
559 return send_sb(&cc->scc, msg, strlen(msg), SBD_OUTPUT, false);
560 }
561
562 /* returns string that must be freed by the caller */
563 static struct server_command *get_cmd_ptr(const char *name, char **handler)
564 {
565 struct server_command *cmd;
566
567 for (cmd = server_cmds; cmd->name; cmd++)
568 if (!strcmp(cmd->name, name)) {
569 if (handler)
570 *handler = para_strdup("server"); /* server commands */
571 return cmd;
572 }
573 /* not found, look for commands supported by afs */
574 for (cmd = afs_cmds; cmd->name; cmd++)
575 if (!strcmp(cmd->name, name)) {
576 if (handler)
577 *handler = para_strdup("afs");
578 return cmd;
579 }
580 return NULL;
581 }
582
583 /* help */
584 static int com_help(struct command_context *cc)
585 {
586 struct server_command *cmd;
587 char *perms, *handler, *buf;
588 int ret;
589
590 if (cc->argc < 2) {
591 /* no argument given, print list of commands */
592 if ((ret = send_list_of_commands(cc, server_cmds, "server")) < 0)
593 return ret;
594 return send_list_of_commands(cc, afs_cmds, "afs");
595 }
596 /* argument given for help */
597 cmd = get_cmd_ptr(cc->argv[1], &handler);
598 if (!cmd)
599 return -E_BAD_CMD;
600 perms = cmd_perms_itohuman(cmd->perms);
601 ret = xasprintf(&buf, "%s - %s\n\n"
602 "handler: %s\n"
603 "permissions: %s\n"
604 "usage: %s\n\n"
605 "%s\n",
606 cc->argv[1],
607 cmd->description,
608 handler,
609 perms,
610 cmd->usage,
611 cmd->help
612 );
613 free(perms);
614 free(handler);
615 return send_sb(&cc->scc, buf, ret, SBD_OUTPUT, false);
616 }
617
618 /* hup */
619 static int com_hup(struct command_context *cc)
620 {
621 if (cc->argc != 1)
622 return -E_COMMAND_SYNTAX;
623 kill(getppid(), SIGHUP);
624 return 1;
625 }
626
627 /* term */
628 static int com_term(struct command_context *cc)
629 {
630 if (cc->argc != 1)
631 return -E_COMMAND_SYNTAX;
632 kill(getppid(), SIGTERM);
633 return 1;
634 }
635
636 static int com_play(struct command_context *cc)
637 {
638 if (cc->argc != 1)
639 return -E_COMMAND_SYNTAX;
640 mutex_lock(mmd_mutex);
641 mmd->new_vss_status_flags |= VSS_PLAYING;
642 mmd->new_vss_status_flags &= ~VSS_NOMORE;
643 mutex_unlock(mmd_mutex);
644 return 1;
645 }
646
647 /* stop */
648 static int com_stop(struct command_context *cc)
649 {
650 if (cc->argc != 1)
651 return -E_COMMAND_SYNTAX;
652 mutex_lock(mmd_mutex);
653 mmd->new_vss_status_flags &= ~VSS_PLAYING;
654 mmd->new_vss_status_flags &= ~VSS_REPOS;
655 mmd->new_vss_status_flags |= VSS_NEXT;
656 mutex_unlock(mmd_mutex);
657 return 1;
658 }
659
660 /* pause */
661 static int com_pause(struct command_context *cc)
662 {
663 if (cc->argc != 1)
664 return -E_COMMAND_SYNTAX;
665 mutex_lock(mmd_mutex);
666 if (!vss_paused() && !vss_stopped()) {
667 mmd->events++;
668 mmd->new_vss_status_flags &= ~VSS_PLAYING;
669 mmd->new_vss_status_flags &= ~VSS_NEXT;
670 }
671 mutex_unlock(mmd_mutex);
672 return 1;
673 }
674
675 /* next */
676 static int com_next(struct command_context *cc)
677 {
678 if (cc->argc != 1)
679 return -E_COMMAND_SYNTAX;
680 mutex_lock(mmd_mutex);
681 mmd->events++;
682 mmd->new_vss_status_flags |= VSS_NEXT;
683 mutex_unlock(mmd_mutex);
684 return 1;
685 }
686
687 /* nomore */
688 static int com_nomore(struct command_context *cc)
689 {
690 if (cc->argc != 1)
691 return -E_COMMAND_SYNTAX;
692 mutex_lock(mmd_mutex);
693 if (vss_playing() || vss_paused())
694 mmd->new_vss_status_flags |= VSS_NOMORE;
695 mutex_unlock(mmd_mutex);
696 return 1;
697 }
698
699 /* ff */
700 static int com_ff(struct command_context *cc)
701 {
702 long promille;
703 int ret, backwards = 0;
704 unsigned i;
705 char c;
706
707 if (cc->argc != 2)
708 return -E_COMMAND_SYNTAX;
709 if (!(ret = sscanf(cc->argv[1], "%u%c", &i, &c)))
710 return -E_COMMAND_SYNTAX;
711 if (ret > 1 && c == '-')
712 backwards = 1; /* jmp backwards */
713 mutex_lock(mmd_mutex);
714 ret = -E_NO_AUDIO_FILE;
715 if (!mmd->afd.afhi.chunks_total || !mmd->afd.afhi.seconds_total)
716 goto out;
717 promille = (1000 * mmd->current_chunk) / mmd->afd.afhi.chunks_total;
718 if (backwards)
719 promille -= 1000 * i / mmd->afd.afhi.seconds_total;
720 else
721 promille += 1000 * i / mmd->afd.afhi.seconds_total;
722 if (promille < 0)
723 promille = 0;
724 if (promille > 1000) {
725 mmd->new_vss_status_flags |= VSS_NEXT;
726 goto out;
727 }
728 mmd->repos_request = (mmd->afd.afhi.chunks_total * promille) / 1000;
729 mmd->new_vss_status_flags |= VSS_REPOS;
730 mmd->new_vss_status_flags &= ~VSS_NEXT;
731 mmd->events++;
732 ret = 1;
733 out:
734 mutex_unlock(mmd_mutex);
735 return ret;
736 }
737
738 /* jmp */
739 static int com_jmp(struct command_context *cc)
740 {
741 long unsigned int i;
742 int ret;
743
744 if (cc->argc != 2)
745 return -E_COMMAND_SYNTAX;
746 if (sscanf(cc->argv[1], "%lu", &i) <= 0)
747 return -E_COMMAND_SYNTAX;
748 mutex_lock(mmd_mutex);
749 ret = -E_NO_AUDIO_FILE;
750 if (!mmd->afd.afhi.chunks_total)
751 goto out;
752 if (i > 100)
753 i = 100;
754 PARA_INFO_LOG("jumping to %lu%%\n", i);
755 mmd->repos_request = (mmd->afd.afhi.chunks_total * i + 50)/ 100;
756 PARA_INFO_LOG("sent: %lu, offset before jmp: %lu\n",
757 mmd->chunks_sent, mmd->offset);
758 mmd->new_vss_status_flags |= VSS_REPOS;
759 mmd->new_vss_status_flags &= ~VSS_NEXT;
760 ret = 1;
761 mmd->events++;
762 out:
763 mutex_unlock(mmd_mutex);
764 return ret;
765 }
766
767 /*
768 * check if perms are sufficient to exec a command having perms cmd_perms.
769 * Returns 0 if perms are sufficient, -E_PERM otherwise.
770 */
771 static int check_perms(unsigned int perms, struct server_command *cmd_ptr)
772 {
773 PARA_DEBUG_LOG("checking permissions\n");
774 return (cmd_ptr->perms & perms) < cmd_ptr->perms ? -E_PERM : 0;
775 }
776
777 static void reset_signals(void)
778 {
779 para_sigaction(SIGCHLD, SIG_IGN);
780 para_sigaction(SIGINT, SIG_DFL);
781 para_sigaction(SIGTERM, SIG_DFL);
782 para_sigaction(SIGHUP, SIG_DFL);
783 }
784
785 struct connection_features {
786 bool sideband_requested;
787 bool aes_ctr128_requested;
788 };
789
790 static int parse_auth_request(char *buf, int len, struct user **u,
791 struct connection_features *cf)
792 {
793 int ret;
794 char *p, *username, **features = NULL;
795 size_t auth_rq_len = strlen(AUTH_REQUEST_MSG);
796
797 *u = NULL;
798 memset(cf, 0, sizeof(*cf));
799 if (len < auth_rq_len + 2)
800 return -E_AUTH_REQUEST;
801 if (strncmp(buf, AUTH_REQUEST_MSG, auth_rq_len) != 0)
802 return -E_AUTH_REQUEST;
803 username = buf + auth_rq_len;
804 p = strchr(username, ' ');
805 if (p) {
806 int i;
807 if (p == username)
808 return -E_AUTH_REQUEST;
809 *p = '\0';
810 p++;
811 create_argv(p, ",", &features);
812 for (i = 0; features[i]; i++) {
813 if (strcmp(features[i], "sideband") == 0)
814 cf->sideband_requested = true;
815 else if (strcmp(features[i], "aes_ctr128") == 0)
816 cf->aes_ctr128_requested = true;
817 else {
818 ret = -E_BAD_FEATURE;
819 goto out;
820 }
821 }
822 }
823 PARA_DEBUG_LOG("received auth request for user %s\n", username);
824 *u = lookup_user(username);
825 ret = 1;
826 out:
827 free_argv(features);
828 return ret;
829 }
830
831 #define HANDSHAKE_BUFSIZE 4096
832
833 static int parse_sb_command(struct command_context *cc, struct iovec *iov)
834 {
835 int ret, i;
836 char *p, *end;
837
838 ret = -E_BAD_CMD;
839 if (iov->iov_base == NULL || iov->iov_len == 0)
840 goto out;
841 p = iov->iov_base;
842 p[iov->iov_len - 1] = '\0'; /* just to be sure */
843 cc->cmd = get_cmd_ptr(p, NULL);
844 if (!cc->cmd)
845 goto out;
846 ret = check_perms(cc->u->perms, cc->cmd);
847 if (ret < 0)
848 goto out;
849 end = iov->iov_base + iov->iov_len;
850 for (i = 0; p < end; i++)
851 p += strlen(p) + 1;
852 cc->argc = i;
853 cc->argv = para_malloc((cc->argc + 1) * sizeof(char *));
854 for (i = 0, p = iov->iov_base; p < end; i++) {
855 cc->argv[i] = para_strdup(p);
856 p += strlen(p) + 1;
857 }
858 cc->argv[cc->argc] = NULL;
859 ret = cc->argc;
860 out:
861 free(iov->iov_base);
862 return ret;
863 }
864
865 /**
866 * Perform user authentication and execute a command.
867 *
868 * \param fd The file descriptor to send output to.
869 * \param peername Identifies the connecting peer.
870 *
871 * Whenever para_server accepts an incoming tcp connection on
872 * the port it listens on, it forks and the resulting child
873 * calls this function.
874 *
875 * An RSA-based challenge/response is used to authenticate
876 * the peer. It that authentication succeeds, a random
877 * session key is generated and sent back to the peer,
878 * encrypted with its RSA public key. From this point on,
879 * all transfers are crypted with this session key.
880 *
881 * Next it is checked if the peer supplied a valid server command or a command
882 * for the audio file selector. If yes, and if the user has sufficient
883 * permissions to execute that command, the function calls the corresponding
884 * command handler which does argument checking and further processing.
885 *
886 * In order to cope with a DOS attacks, a timeout is set up
887 * which terminates the function if the connection was not
888 * authenticated when the timeout expires.
889 *
890 * \sa alarm(2), crypt.c, crypt.h
891 */
892 __noreturn void handle_connect(int fd, const char *peername)
893 {
894 int ret;
895 unsigned char rand_buf[CHALLENGE_SIZE + 2 * SESSION_KEY_LEN];
896 unsigned char challenge_hash[HASH_SIZE];
897 char *command = NULL, *buf = para_malloc(HANDSHAKE_BUFSIZE) /* must be on the heap */;
898 size_t numbytes;
899 struct command_context cc_struct = {.peer = peername}, *cc = &cc_struct;
900 struct iovec iov;
901 struct connection_features cf;
902
903 cc->scc.fd = fd;
904 reset_signals();
905 /* we need a blocking fd here as recv() might return EAGAIN otherwise. */
906 ret = mark_fd_blocking(fd);
907 if (ret < 0)
908 goto net_err;
909 /* send Welcome message */
910 ret = write_va_buffer(fd, "This is para_server, version "
911 PACKAGE_VERSION ".\n"
912 "Features: sideband,aes_ctr128\n"
913 );
914 if (ret < 0)
915 goto net_err;
916 /* recv auth request line */
917 ret = recv_buffer(fd, buf, HANDSHAKE_BUFSIZE);
918 if (ret < 0)
919 goto net_err;
920 ret = parse_auth_request(buf, ret, &cc->u, &cf);
921 if (ret < 0)
922 goto net_err;
923 if (!cf.sideband_requested) { /* sideband is mandatory */
924 PARA_ERROR_LOG("client did not request sideband\n");
925 ret = -E_BAD_FEATURE;
926 goto net_err;
927 }
928 if (cc->u) {
929 get_random_bytes_or_die(rand_buf, sizeof(rand_buf));
930 ret = pub_encrypt(cc->u->pubkey, rand_buf, sizeof(rand_buf),
931 (unsigned char *)buf);
932 if (ret < 0)
933 goto net_err;
934 numbytes = ret;
935 } else {
936 /*
937 * We don't want to reveal our user names, so we send a
938 * challenge to the client even if the user does not exist, and
939 * fail the authentication later.
940 */
941 numbytes = 256;
942 get_random_bytes_or_die((unsigned char *)buf, numbytes);
943 }
944 PARA_DEBUG_LOG("sending %u byte challenge + session key (%zu bytes)\n",
945 CHALLENGE_SIZE, numbytes);
946 ret = send_sb(&cc->scc, buf, numbytes, SBD_CHALLENGE, false);
947 buf = NULL;
948 if (ret < 0)
949 goto net_err;
950 ret = recv_sb(&cc->scc, SBD_CHALLENGE_RESPONSE,
951 HANDSHAKE_BUFSIZE, &iov);
952 if (ret < 0)
953 goto net_err;
954 buf = iov.iov_base;
955 numbytes = iov.iov_len;
956 PARA_DEBUG_LOG("received %zu bytes challenge response\n", numbytes);
957 ret = -E_BAD_USER;
958 if (!cc->u)
959 goto net_err;
960 /*
961 * The correct response is the hash of the first CHALLENGE_SIZE bytes
962 * of the random data.
963 */
964 ret = -E_BAD_AUTH;
965 if (numbytes != HASH_SIZE)
966 goto net_err;
967 hash_function((char *)rand_buf, CHALLENGE_SIZE, challenge_hash);
968 if (memcmp(challenge_hash, buf, HASH_SIZE))
969 goto net_err;
970 /* auth successful */
971 alarm(0);
972 PARA_INFO_LOG("good auth for %s\n", cc->u->name);
973 /* init stream cipher keys with the second part of the random buffer */
974 cc->scc.recv = sc_new(rand_buf + CHALLENGE_SIZE, SESSION_KEY_LEN,
975 cf.aes_ctr128_requested);
976 cc->scc.send = sc_new(rand_buf + CHALLENGE_SIZE + SESSION_KEY_LEN,
977 SESSION_KEY_LEN, cf.aes_ctr128_requested);
978 ret = send_sb(&cc->scc, NULL, 0, SBD_PROCEED, false);
979 if (ret < 0)
980 goto net_err;
981 ret = recv_sb(&cc->scc, SBD_COMMAND, MAX_COMMAND_LEN, &iov);
982 if (ret < 0)
983 goto net_err;
984 ret = parse_sb_command(cc, &iov);
985 if (ret < 0)
986 goto err_out;
987 cc->argc = ret;
988 PARA_NOTICE_LOG("calling com_%s() for %s@%s\n", cc->cmd->name,
989 cc->u->name, peername);
990 ret = cc->cmd->handler(cc);
991 free_argv(cc->argv);
992 mutex_lock(mmd_mutex);
993 mmd->num_commands++;
994 mutex_unlock(mmd_mutex);
995 if (ret >= 0)
996 goto out;
997 err_out:
998 if (send_strerror(cc, -ret) >= 0)
999 send_sb(&cc->scc, NULL, 0, SBD_EXIT__FAILURE, true);
1000 net_err:
1001 PARA_NOTICE_LOG("%s\n", para_strerror(-ret));
1002 out:
1003 free(buf);
1004 free(command);
1005 mutex_lock(mmd_mutex);
1006 if (cc->cmd && (cc->cmd->perms & AFS_WRITE) && ret >= 0)
1007 mmd->events++;
1008 mmd->active_connections--;
1009 mutex_unlock(mmd_mutex);
1010 if (ret >= 0) {
1011 ret = send_sb(&cc->scc, NULL, 0, SBD_EXIT__SUCCESS, true);
1012 if (ret < 0)
1013 PARA_NOTICE_LOG("%s\n", para_strerror(-ret));
1014 }
1015 sc_free(cc->scc.recv);
1016 sc_free(cc->scc.send);
1017 exit(ret < 0? EXIT_FAILURE : EXIT_SUCCESS);
1018 }