Merge branch 'maint'
[paraslash.git] / command.c
1 /*
2 * Copyright (C) 1997 Andre Noll <maan@tuebingen.mpg.de>
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 necessary 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 if (strcmp(cc->argv[2], "status") == 0)
348 msg = senders[scd.sender_num].status();
349 else
350 msg = senders[scd.sender_num].help();
351 return send_sb(&cc->scc, msg, strlen(msg), SBD_OUTPUT, false);
352 }
353
354 switch (scd.cmd_num) {
355 case SENDER_ADD:
356 case SENDER_DELETE:
357 assert(senders[scd.sender_num].resolve_target);
358 ret = senders[scd.sender_num].resolve_target(cc->argv[3], &scd);
359 if (ret < 0)
360 return ret;
361 }
362
363 for (i = 0; i < 10; i++) {
364 mutex_lock(mmd_mutex);
365 if (mmd->sender_cmd_data.cmd_num >= 0) {
366 /* another sender command is active, retry in 100ms */
367 struct timespec ts = {.tv_nsec = 100 * 1000 * 1000};
368 mutex_unlock(mmd_mutex);
369 nanosleep(&ts, NULL);
370 continue;
371 }
372 mmd->sender_cmd_data = scd;
373 mutex_unlock(mmd_mutex);
374 break;
375 }
376 return (i < 10)? 1 : -E_LOCK;
377 }
378
379 /* server info */
380 static int com_si(struct command_context *cc)
381 {
382 int ret;
383 char *msg, *ut;
384
385 if (cc->argc != 1)
386 return -E_COMMAND_SYNTAX;
387 mutex_lock(mmd_mutex);
388 ut = daemon_get_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 ut, mmd->num_played,
397 (int)getppid(),
398 (int)mmd->afs_pid,
399 mmd->active_connections,
400 mmd->num_commands,
401 mmd->num_connects,
402 conf.loglevel_arg,
403 AUDIO_FORMAT_HANDLERS
404 );
405 mutex_unlock(mmd_mutex);
406 free(ut);
407 return send_sb(&cc->scc, msg, ret, SBD_OUTPUT, false);
408 }
409
410 /* version */
411 static int com_version(struct command_context *cc)
412 {
413 char *msg;
414 size_t len;
415
416 if (cc->argc != 1)
417 return -E_COMMAND_SYNTAX;
418 len = xasprintf(&msg, "%s", version_text("server"));
419 return send_sb(&cc->scc, msg, len, SBD_OUTPUT, false);
420 }
421
422 /** These status items are cleared if no audio file is currently open. */
423 #define EMPTY_STATUS_ITEMS \
424 ITEM(PATH) \
425 ITEM(DIRECTORY) \
426 ITEM(BASENAME) \
427 ITEM(SCORE) \
428 ITEM(ATTRIBUTES_BITMAP) \
429 ITEM(ATTRIBUTES_TXT) \
430 ITEM(HASH) \
431 ITEM(IMAGE_ID) \
432 ITEM(IMAGE_NAME) \
433 ITEM(LYRICS_ID) \
434 ITEM(LYRICS_NAME) \
435 ITEM(BITRATE) \
436 ITEM(FORMAT) \
437 ITEM(FREQUENCY) \
438 ITEM(CHANNELS) \
439 ITEM(DURATION) \
440 ITEM(SECONDS_TOTAL) \
441 ITEM(NUM_PLAYED) \
442 ITEM(LAST_PLAYED) \
443 ITEM(TECHINFO) \
444 ITEM(ARTIST) \
445 ITEM(TITLE) \
446 ITEM(YEAR) \
447 ITEM(ALBUM) \
448 ITEM(COMMENT) \
449 ITEM(MTIME) \
450 ITEM(FILE_SIZE) \
451 ITEM(CHUNK_TIME) \
452 ITEM(NUM_CHUNKS) \
453 ITEM(AMPLIFICATION) \
454
455 /**
456 * Write a list of audio-file related status items with empty values.
457 *
458 * This is used by vss when currently no audio file is open.
459 */
460 static unsigned empty_status_items(int parser_friendly, char **result)
461 {
462 char *esi;
463 unsigned len;
464
465 if (parser_friendly)
466 len = xasprintf(&esi,
467 #define ITEM(x) "0004 %02x:\n"
468 EMPTY_STATUS_ITEMS
469 #undef ITEM
470 #define ITEM(x) , SI_ ## x
471 EMPTY_STATUS_ITEMS
472 #undef ITEM
473 );
474 else
475 len = xasprintf(&esi,
476 #define ITEM(x) "%s:\n"
477 EMPTY_STATUS_ITEMS
478 #undef ITEM
479 #define ITEM(x) ,status_item_list[SI_ ## x]
480 EMPTY_STATUS_ITEMS
481 #undef ITEM
482 );
483 *result = esi;
484 return len;
485 }
486 #undef EMPTY_STATUS_ITEMS
487
488 /* stat */
489 static int com_stat(struct command_context *cc)
490 {
491 int i, ret;
492 struct misc_meta_data tmp, *nmmd = &tmp;
493 char *s;
494 int32_t num = 0;
495 int parser_friendly = 0;
496
497 para_sigaction(SIGUSR1, dummy);
498
499 for (i = 1; i < cc->argc; i++) {
500 const char *arg = cc->argv[i];
501 if (arg[0] != '-')
502 break;
503 if (!strcmp(arg, "--")) {
504 i++;
505 break;
506 }
507 if (!strncmp(arg, "-n=", 3)) {
508 ret = para_atoi32(arg + 3, &num);
509 if (ret < 0)
510 return ret;
511 continue;
512 }
513 if (!strcmp(arg, "-p")) {
514 parser_friendly = 1;
515 continue;
516 }
517 return -E_COMMAND_SYNTAX;
518 }
519 if (i != cc->argc)
520 return -E_COMMAND_SYNTAX;
521 for (;;) {
522 mmd_dup(nmmd);
523 ret = get_status(nmmd, parser_friendly, &s);
524 ret = send_sb(&cc->scc, s, ret, SBD_OUTPUT, false);
525 if (ret < 0)
526 goto out;
527 if (nmmd->vss_status_flags & VSS_NEXT) {
528 char *esi;
529 ret = empty_status_items(parser_friendly, &esi);
530 ret = send_sb(&cc->scc, esi, ret, SBD_OUTPUT, false);
531 if (ret < 0)
532 goto out;
533 } else
534 send_afs_status(cc, parser_friendly);
535 ret = 1;
536 if (num > 0 && !--num)
537 goto out;
538 sleep(50);
539 ret = -E_SERVER_CRASH;
540 if (getppid() == 1)
541 goto out;
542 }
543 out:
544 return ret;
545 }
546
547 static int send_list_of_commands(struct command_context *cc, struct server_command *cmd,
548 const char *handler)
549 {
550 char *msg = NULL;
551
552 for (; cmd->name; cmd++) {
553 char *tmp, *perms = cmd_perms_itohuman(cmd->perms);
554 tmp = make_message("%s\t%s\t%s\t%s\n", cmd->name, handler,
555 perms, cmd->description);
556 free(perms);
557 msg = para_strcat(msg, tmp);
558 free(tmp);
559 }
560 assert(msg);
561 return send_sb(&cc->scc, msg, strlen(msg), SBD_OUTPUT, false);
562 }
563
564 /* returns string that must be freed by the caller */
565 static struct server_command *get_cmd_ptr(const char *name, char **handler)
566 {
567 struct server_command *cmd;
568
569 for (cmd = server_cmds; cmd->name; cmd++)
570 if (!strcmp(cmd->name, name)) {
571 if (handler)
572 *handler = para_strdup("server"); /* server commands */
573 return cmd;
574 }
575 /* not found, look for commands supported by afs */
576 for (cmd = afs_cmds; cmd->name; cmd++)
577 if (!strcmp(cmd->name, name)) {
578 if (handler)
579 *handler = para_strdup("afs");
580 return cmd;
581 }
582 return NULL;
583 }
584
585 /* help */
586 static int com_help(struct command_context *cc)
587 {
588 struct server_command *cmd;
589 char *perms, *handler, *buf;
590 int ret;
591
592 if (cc->argc < 2) {
593 /* no argument given, print list of commands */
594 if ((ret = send_list_of_commands(cc, server_cmds, "server")) < 0)
595 return ret;
596 return send_list_of_commands(cc, afs_cmds, "afs");
597 }
598 /* argument given for help */
599 cmd = get_cmd_ptr(cc->argv[1], &handler);
600 if (!cmd)
601 return -E_BAD_CMD;
602 perms = cmd_perms_itohuman(cmd->perms);
603 ret = xasprintf(&buf, "%s - %s\n\n"
604 "handler: %s\n"
605 "permissions: %s\n"
606 "usage: %s\n\n"
607 "%s\n",
608 cc->argv[1],
609 cmd->description,
610 handler,
611 perms,
612 cmd->usage,
613 cmd->help
614 );
615 free(perms);
616 free(handler);
617 return send_sb(&cc->scc, buf, ret, SBD_OUTPUT, false);
618 }
619
620 /* hup */
621 static int com_hup(struct command_context *cc)
622 {
623 if (cc->argc != 1)
624 return -E_COMMAND_SYNTAX;
625 kill(getppid(), SIGHUP);
626 return 1;
627 }
628
629 /* term */
630 static int com_term(struct command_context *cc)
631 {
632 if (cc->argc != 1)
633 return -E_COMMAND_SYNTAX;
634 kill(getppid(), SIGTERM);
635 return 1;
636 }
637
638 static int com_play(struct command_context *cc)
639 {
640 if (cc->argc != 1)
641 return -E_COMMAND_SYNTAX;
642 mutex_lock(mmd_mutex);
643 mmd->new_vss_status_flags |= VSS_PLAYING;
644 mmd->new_vss_status_flags &= ~VSS_NOMORE;
645 mutex_unlock(mmd_mutex);
646 return 1;
647 }
648
649 /* stop */
650 static int com_stop(struct command_context *cc)
651 {
652 if (cc->argc != 1)
653 return -E_COMMAND_SYNTAX;
654 mutex_lock(mmd_mutex);
655 mmd->new_vss_status_flags &= ~VSS_PLAYING;
656 mmd->new_vss_status_flags &= ~VSS_REPOS;
657 mmd->new_vss_status_flags |= VSS_NEXT;
658 mutex_unlock(mmd_mutex);
659 return 1;
660 }
661
662 /* pause */
663 static int com_pause(struct command_context *cc)
664 {
665 if (cc->argc != 1)
666 return -E_COMMAND_SYNTAX;
667 mutex_lock(mmd_mutex);
668 if (!vss_paused() && !vss_stopped()) {
669 mmd->events++;
670 mmd->new_vss_status_flags &= ~VSS_PLAYING;
671 mmd->new_vss_status_flags &= ~VSS_NEXT;
672 }
673 mutex_unlock(mmd_mutex);
674 return 1;
675 }
676
677 /* next */
678 static int com_next(struct command_context *cc)
679 {
680 if (cc->argc != 1)
681 return -E_COMMAND_SYNTAX;
682 mutex_lock(mmd_mutex);
683 mmd->events++;
684 mmd->new_vss_status_flags |= VSS_NEXT;
685 mutex_unlock(mmd_mutex);
686 return 1;
687 }
688
689 /* nomore */
690 static int com_nomore(struct command_context *cc)
691 {
692 if (cc->argc != 1)
693 return -E_COMMAND_SYNTAX;
694 mutex_lock(mmd_mutex);
695 if (vss_playing() || vss_paused())
696 mmd->new_vss_status_flags |= VSS_NOMORE;
697 mutex_unlock(mmd_mutex);
698 return 1;
699 }
700
701 /* ff */
702 static int com_ff(struct command_context *cc)
703 {
704 long promille;
705 int ret, backwards = 0;
706 unsigned i;
707 char c;
708
709 if (cc->argc != 2)
710 return -E_COMMAND_SYNTAX;
711 if (!(ret = sscanf(cc->argv[1], "%u%c", &i, &c)))
712 return -E_COMMAND_SYNTAX;
713 if (ret > 1 && c == '-')
714 backwards = 1; /* jmp backwards */
715 mutex_lock(mmd_mutex);
716 ret = -E_NO_AUDIO_FILE;
717 if (!mmd->afd.afhi.chunks_total || !mmd->afd.afhi.seconds_total)
718 goto out;
719 promille = (1000 * mmd->current_chunk) / mmd->afd.afhi.chunks_total;
720 if (backwards)
721 promille -= 1000 * i / mmd->afd.afhi.seconds_total;
722 else
723 promille += 1000 * i / mmd->afd.afhi.seconds_total;
724 if (promille < 0)
725 promille = 0;
726 if (promille > 1000) {
727 mmd->new_vss_status_flags |= VSS_NEXT;
728 goto out;
729 }
730 mmd->repos_request = (mmd->afd.afhi.chunks_total * promille) / 1000;
731 mmd->new_vss_status_flags |= VSS_REPOS;
732 mmd->new_vss_status_flags &= ~VSS_NEXT;
733 mmd->events++;
734 ret = 1;
735 out:
736 mutex_unlock(mmd_mutex);
737 return ret;
738 }
739
740 /* jmp */
741 static int com_jmp(struct command_context *cc)
742 {
743 long unsigned int i;
744 int ret;
745
746 if (cc->argc != 2)
747 return -E_COMMAND_SYNTAX;
748 if (sscanf(cc->argv[1], "%lu", &i) <= 0)
749 return -E_COMMAND_SYNTAX;
750 mutex_lock(mmd_mutex);
751 ret = -E_NO_AUDIO_FILE;
752 if (!mmd->afd.afhi.chunks_total)
753 goto out;
754 if (i > 100)
755 i = 100;
756 PARA_INFO_LOG("jumping to %lu%%\n", i);
757 mmd->repos_request = (mmd->afd.afhi.chunks_total * i + 50) / 100;
758 PARA_INFO_LOG("sent: %lu, offset before jmp: %lu\n",
759 mmd->chunks_sent, mmd->offset);
760 mmd->new_vss_status_flags |= VSS_REPOS;
761 mmd->new_vss_status_flags &= ~VSS_NEXT;
762 ret = 1;
763 mmd->events++;
764 out:
765 mutex_unlock(mmd_mutex);
766 return ret;
767 }
768
769 static int com_tasks(struct command_context *cc)
770 {
771 char *tl = server_get_tasks();
772 int ret = 1;
773
774 if (tl)
775 ret = send_sb(&cc->scc, tl, strlen(tl), SBD_OUTPUT, false);
776 return ret;
777 }
778
779 /*
780 * check if perms are sufficient to exec a command having perms cmd_perms.
781 * Returns 0 if perms are sufficient, -E_PERM otherwise.
782 */
783 static int check_perms(unsigned int perms, struct server_command *cmd_ptr)
784 {
785 PARA_DEBUG_LOG("checking permissions\n");
786 return (cmd_ptr->perms & perms) < cmd_ptr->perms ? -E_PERM : 0;
787 }
788
789 static void reset_signals(void)
790 {
791 para_sigaction(SIGCHLD, SIG_IGN);
792 para_sigaction(SIGINT, SIG_DFL);
793 para_sigaction(SIGTERM, SIG_DFL);
794 para_sigaction(SIGHUP, SIG_DFL);
795 }
796
797 struct connection_features {
798 bool sideband_requested;
799 bool aes_ctr128_requested;
800 };
801
802 static int parse_auth_request(char *buf, int len, struct user **u,
803 struct connection_features *cf)
804 {
805 int ret;
806 char *p, *username, **features = NULL;
807 size_t auth_rq_len = strlen(AUTH_REQUEST_MSG);
808
809 *u = NULL;
810 memset(cf, 0, sizeof(*cf));
811 if (len < auth_rq_len + 2)
812 return -E_AUTH_REQUEST;
813 if (strncmp(buf, AUTH_REQUEST_MSG, auth_rq_len) != 0)
814 return -E_AUTH_REQUEST;
815 username = buf + auth_rq_len;
816 p = strchr(username, ' ');
817 if (p) {
818 int i;
819 if (p == username)
820 return -E_AUTH_REQUEST;
821 *p = '\0';
822 p++;
823 create_argv(p, ",", &features);
824 for (i = 0; features[i]; i++) {
825 if (strcmp(features[i], "sideband") == 0)
826 cf->sideband_requested = true;
827 else if (strcmp(features[i], "aes_ctr128") == 0)
828 cf->aes_ctr128_requested = true;
829 else {
830 ret = -E_BAD_FEATURE;
831 goto out;
832 }
833 }
834 }
835 PARA_DEBUG_LOG("received auth request for user %s\n", username);
836 *u = lookup_user(username);
837 ret = 1;
838 out:
839 free_argv(features);
840 return ret;
841 }
842
843 #define HANDSHAKE_BUFSIZE 4096
844
845 static int parse_sb_command(struct command_context *cc, struct iovec *iov)
846 {
847 int ret, i;
848 char *p, *end;
849
850 ret = -E_BAD_CMD;
851 if (iov->iov_base == NULL || iov->iov_len == 0)
852 goto out;
853 p = iov->iov_base;
854 p[iov->iov_len - 1] = '\0'; /* just to be sure */
855 cc->cmd = get_cmd_ptr(p, NULL);
856 if (!cc->cmd)
857 goto out;
858 ret = check_perms(cc->u->perms, cc->cmd);
859 if (ret < 0)
860 goto out;
861 end = iov->iov_base + iov->iov_len;
862 for (i = 0; p < end; i++)
863 p += strlen(p) + 1;
864 cc->argc = i;
865 cc->argv = para_malloc((cc->argc + 1) * sizeof(char *));
866 for (i = 0, p = iov->iov_base; p < end; i++) {
867 cc->argv[i] = para_strdup(p);
868 p += strlen(p) + 1;
869 }
870 cc->argv[cc->argc] = NULL;
871 ret = cc->argc;
872 out:
873 free(iov->iov_base);
874 return ret;
875 }
876
877 /**
878 * Perform user authentication and execute a command.
879 *
880 * \param fd The file descriptor to send output to.
881 * \param peername Identifies the connecting peer.
882 *
883 * Whenever para_server accepts an incoming tcp connection on the port it
884 * listens on, it forks and the resulting child calls this function.
885 *
886 * An RSA-based challenge/response is used to authenticate the peer. It that
887 * authentication succeeds, a random session key is generated and sent back to
888 * the peer, encrypted with its RSA public key. From this point on, all
889 * transfers are crypted with this session key.
890 *
891 * Next it is checked if the peer supplied a valid server command or a command
892 * for the audio file selector. If yes, and if the user has sufficient
893 * permissions to execute that command, the function calls the corresponding
894 * command handler which does argument checking and further processing.
895 *
896 * In order to cope with a DOS attacks, a timeout is set up which terminates
897 * the function if the connection was not authenticated when the timeout
898 * expires.
899 *
900 * \sa alarm(2), crypt.c, crypt.h
901 */
902 __noreturn void handle_connect(int fd, const char *peername)
903 {
904 int ret;
905 unsigned char rand_buf[CHALLENGE_SIZE + 2 * SESSION_KEY_LEN];
906 unsigned char challenge_hash[HASH_SIZE];
907 char *command = NULL, *buf = para_malloc(HANDSHAKE_BUFSIZE) /* must be on the heap */;
908 size_t numbytes;
909 struct command_context cc_struct = {.peer = peername}, *cc = &cc_struct;
910 struct iovec iov;
911 struct connection_features cf;
912
913 cc->scc.fd = fd;
914 reset_signals();
915 /* we need a blocking fd here as recv() might return EAGAIN otherwise. */
916 ret = mark_fd_blocking(fd);
917 if (ret < 0)
918 goto net_err;
919 /* send Welcome message */
920 ret = write_va_buffer(fd, "This is para_server, version "
921 PACKAGE_VERSION ".\n"
922 "Features: sideband,aes_ctr128\n"
923 );
924 if (ret < 0)
925 goto net_err;
926 /* recv auth request line */
927 ret = recv_buffer(fd, buf, HANDSHAKE_BUFSIZE);
928 if (ret < 0)
929 goto net_err;
930 ret = parse_auth_request(buf, ret, &cc->u, &cf);
931 if (ret < 0)
932 goto net_err;
933 if (!cf.sideband_requested) { /* sideband is mandatory */
934 PARA_ERROR_LOG("client did not request sideband\n");
935 ret = -E_BAD_FEATURE;
936 goto net_err;
937 }
938 if (cc->u) {
939 get_random_bytes_or_die(rand_buf, sizeof(rand_buf));
940 ret = pub_encrypt(cc->u->pubkey, rand_buf, sizeof(rand_buf),
941 (unsigned char *)buf);
942 if (ret < 0)
943 goto net_err;
944 numbytes = ret;
945 } else {
946 /*
947 * We don't want to reveal our user names, so we send a
948 * challenge to the client even if the user does not exist, and
949 * fail the authentication later.
950 */
951 numbytes = 256;
952 get_random_bytes_or_die((unsigned char *)buf, numbytes);
953 }
954 PARA_DEBUG_LOG("sending %u byte challenge + session key (%zu bytes)\n",
955 CHALLENGE_SIZE, numbytes);
956 ret = send_sb(&cc->scc, buf, numbytes, SBD_CHALLENGE, false);
957 buf = NULL;
958 if (ret < 0)
959 goto net_err;
960 ret = recv_sb(&cc->scc, SBD_CHALLENGE_RESPONSE,
961 HANDSHAKE_BUFSIZE, &iov);
962 if (ret < 0)
963 goto net_err;
964 buf = iov.iov_base;
965 numbytes = iov.iov_len;
966 PARA_DEBUG_LOG("received %zu bytes challenge response\n", numbytes);
967 ret = -E_BAD_USER;
968 if (!cc->u)
969 goto net_err;
970 /*
971 * The correct response is the hash of the first CHALLENGE_SIZE bytes
972 * of the random data.
973 */
974 ret = -E_BAD_AUTH;
975 if (numbytes != HASH_SIZE)
976 goto net_err;
977 hash_function((char *)rand_buf, CHALLENGE_SIZE, challenge_hash);
978 if (memcmp(challenge_hash, buf, HASH_SIZE))
979 goto net_err;
980 /* auth successful */
981 alarm(0);
982 PARA_INFO_LOG("good auth for %s\n", cc->u->name);
983 /* init stream cipher keys with the second part of the random buffer */
984 cc->scc.recv = sc_new(rand_buf + CHALLENGE_SIZE, SESSION_KEY_LEN,
985 cf.aes_ctr128_requested);
986 cc->scc.send = sc_new(rand_buf + CHALLENGE_SIZE + SESSION_KEY_LEN,
987 SESSION_KEY_LEN, cf.aes_ctr128_requested);
988 ret = send_sb(&cc->scc, NULL, 0, SBD_PROCEED, false);
989 if (ret < 0)
990 goto net_err;
991 ret = recv_sb(&cc->scc, SBD_COMMAND, MAX_COMMAND_LEN, &iov);
992 if (ret < 0)
993 goto net_err;
994 ret = parse_sb_command(cc, &iov);
995 if (ret < 0)
996 goto err_out;
997 cc->argc = ret;
998 PARA_NOTICE_LOG("calling com_%s() for %s@%s\n", cc->cmd->name,
999 cc->u->name, peername);
1000 ret = cc->cmd->handler(cc);
1001 free_argv(cc->argv);
1002 mutex_lock(mmd_mutex);
1003 mmd->num_commands++;
1004 mutex_unlock(mmd_mutex);
1005 if (ret >= 0)
1006 goto out;
1007 err_out:
1008 if (send_strerror(cc, -ret) >= 0)
1009 send_sb(&cc->scc, NULL, 0, SBD_EXIT__FAILURE, true);
1010 net_err:
1011 PARA_NOTICE_LOG("%s\n", para_strerror(-ret));
1012 out:
1013 free(buf);
1014 free(command);
1015 mutex_lock(mmd_mutex);
1016 if (cc->cmd && (cc->cmd->perms & AFS_WRITE) && ret >= 0)
1017 mmd->events++;
1018 mmd->active_connections--;
1019 mutex_unlock(mmd_mutex);
1020 if (ret >= 0) {
1021 ret = send_sb(&cc->scc, NULL, 0, SBD_EXIT__SUCCESS, true);
1022 if (ret < 0)
1023 PARA_NOTICE_LOG("%s\n", para_strerror(-ret));
1024 }
1025 sc_free(cc->scc.recv);
1026 sc_free(cc->scc.send);
1027 exit(ret < 0? EXIT_FAILURE : EXIT_SUCCESS);
1028 }