command.c

   1 /*
   2  * Copyright (C) 1997-2007 Andre Noll <maan@systemlinux.org>
   3  *
   4  * Licensed under the GPL v2. For licencing details see COPYING.
   5  */
   6
   7 /** \file command.c does client authentication and executes server commands */
   8
   9 #include <sys/time.h> /* gettimeofday */
  10 #include "para.h" /* gettimeofday */
  11
  12 #include "server.cmdline.h"
  13 #include "afs_common.h"
  14 #include "afh.h"
  15 #include "server.h"
  16 #include "vss.h"
  17 #include "send.h"
  18 #include "rc4.h"
  19 #include <openssl/rc4.h>
  20 #include "error.h"
  21 #include "net.h"
  22 #include "daemon.h"
  23 #include "string.h"
  24 #include "fd.h"
  25 #include "list.h"
  26 #include "user_list.h"
  27 #include "server_command_list.h"
  28 #include "afs_command_list.h"
  29
  30 /** commands including options must be shorter than this */
  31 #define MAX_COMMAND_LEN 32768
  32
  33 static RC4_KEY rc4_recv_key;
  34 static RC4_KEY rc4_send_key;
  35 static unsigned char rc4_buf[2 * RC4_KEY_LEN];
  36
  37 extern const char *status_item_list[NUM_STAT_ITEMS];
  38 extern struct misc_meta_data *mmd;
  39 extern struct audio_file_selector selectors[];
  40 extern struct sender senders[];
  41
  42 static void dummy(__a_unused int s)
  43 {}
  44
  45 static void mmd_dup(struct misc_meta_data *new_mmd)
  46 {
  47         mmd_lock();
  48         *new_mmd = *mmd;
  49         mmd_unlock();
  50 }
  51
  52 /*
  53  * compute human readable string containing
  54  * vss status for given integer value
  55  */
  56 static char *vss_status_tohuman(unsigned int flags)
  57 {
  58         if (flags & VSS_PLAYING)
  59                 return para_strdup("playing");
  60         else if (flags & VSS_NEXT)
  61                 return para_strdup("stopped");
  62         else
  63                 return para_strdup("paused");
  64 }
  65
  66 /*
  67  * return human readable permission string. Never returns NULL.
  68  */
  69 static char *cmd_perms_itohuman(unsigned int perms)
  70 {
  71         char *msg = para_malloc(5 * sizeof(char));
  72
  73         msg[0] = perms & AFS_READ? 'a' : '-';
  74         msg[1] = perms & AFS_WRITE? 'A' : '-';
  75         msg[2] = perms & VSS_READ? 'v' : '-';
  76         msg[3] = perms & VSS_WRITE? 'V' : '-';
  77         msg[4] = '\0';
  78         return msg;
  79 }
  80
  81 /*
  82  * Never returns NULL.
  83  */
  84 static char *vss_get_status_flags(unsigned int flags)
  85 {
  86         char *msg = para_malloc(5 * sizeof(char));
  87
  88         msg[0] = (flags & VSS_PLAYING)? 'P' : '_';
  89         msg[1] = (flags & VSS_NOMORE)? 'O' : '_';
  90         msg[2] = (flags & VSS_NEXT)? 'N' : '_';
  91         msg[3] = (flags & VSS_REPOS)? 'R' : '_';
  92         msg[4] = '\0';
  93         return msg;
  94 }
  95
  96 /*
  97  * compute status bar string. Never returns NULL
  98  */
  99 static char *get_sb_string(struct misc_meta_data *nmmd)
 100 {
 101         char *base, *ret;
 102         long long unsigned secs = 0, rsecs = 0, percent = 0;
 103
 104         base = para_basename(nmmd->filename);
 105         if (!base)
 106                 return para_strdup("");
 107         if (!base[0])
 108                 return base;
 109         if (nmmd->afi.chunks_total) {
 110                 secs = (long long) nmmd->afi.seconds_total * nmmd->chunks_sent
 111                         / nmmd->afi.chunks_total;
 112                 rsecs = (long long) nmmd->afi.seconds_total *
 113                         (nmmd->afi.chunks_total - nmmd->chunks_sent)
 114                         / nmmd->afi.chunks_total;
 115                 percent = 100 * ((nmmd->chunks_sent + 5) / 10)
 116                         / ((nmmd->afi.chunks_total + 5) / 10);
 117         }
 118         ret = make_message("%llu:%02llu [%llu:%02llu] (%llu%%) %s",
 119                 secs / 60, secs % 60,
 120                 rsecs / 60, rsecs % 60,
 121                 percent,
 122                 base
 123         );
 124         free(base);
 125         return ret;
 126 }
 127
 128 static char *get_status(struct misc_meta_data *nmmd)
 129 {
 130         char *bar, *ret, mtime[30] = "";
 131         char *status, *flags; /* vss status info */
 132         char *ut = uptime_str();
 133         long offset = (nmmd->offset + 500) / 1000;
 134         struct timeval now;
 135         struct tm mtime_tm;
 136
 137         if (nmmd->audio_format >= 0) {
 138                 localtime_r(&nmmd->mtime, &mtime_tm);
 139                 strftime(mtime, 29, "%a %b %d %Y", &mtime_tm);
 140         }
 141         /* report real status */
 142         status = vss_status_tohuman(nmmd->vss_status_flags);
 143         flags = vss_get_status_flags(nmmd->vss_status_flags);
 144         bar = para_basename(nmmd->filename);
 145         gettimeofday(&now, NULL);
 146         ret = make_message(
 147                 "%s:%zu\n"      "%s:%s\n"               "%s:%lu\n"      "%s:%u\n"
 148                 "%s:%s\n"       "%s:%s\n"       "%s:%s\n"       "%s:%s\n"
 149                 "%s:%li\n"      "%s:%s\n"       "%s"            "%s"
 150                 "%s:%s\n"       "%s:%lu.%lu\n"  "%s:%lu.%lu\n",
 151                 status_item_list[SI_FILE_SIZE], nmmd->size / 1024,
 152                 status_item_list[SI_MTIME], mtime,
 153                 status_item_list[SI_LENGTH], nmmd->afi.seconds_total,
 154                 status_item_list[SI_NUM_PLAYED], nmmd->num_played,
 155
 156                 status_item_list[SI_STATUS_BAR], bar ? bar : "(none)",
 157                 status_item_list[SI_STATUS], status,
 158                 status_item_list[SI_STATUS_FLAGS], flags,
 159                 status_item_list[SI_SELECTOR], selectors[nmmd->selector_num].name,
 160
 161                 status_item_list[SI_OFFSET], offset,
 162                 status_item_list[SI_FORMAT], audio_format_name(nmmd->audio_format),
 163                 nmmd->selector_info,
 164                 nmmd->afi.info_string,
 165
 166                 status_item_list[SI_UPTIME], ut,
 167                 status_item_list[SI_STREAM_START],
 168                         (long unsigned)nmmd->stream_start.tv_sec,
 169                         (long unsigned)nmmd->stream_start.tv_usec,
 170                 status_item_list[SI_CURRENT_TIME],
 171                         (long unsigned)now.tv_sec,
 172                         (long unsigned)now.tv_usec
 173
 174         );
 175         free(bar);
 176         free(flags);
 177         free(status);
 178         free(ut);
 179         return ret;
 180 }
 181
 182 static int check_sender_args(int argc, char * const * argv, struct sender_command_data *scd)
 183 {
 184         int i;
 185         /* this has to match sender.h */
 186         const char *subcmds[] = {"add", "delete", "allow", "deny", "on", "off", NULL};
 187
 188         scd->sender_num = -1;
 189         if (argc < 2)
 190                 return -E_COMMAND_SYNTAX;
 191         for (i = 0; senders[i].name; i++)
 192                 if (!strcmp(senders[i].name, argv[1]))
 193                         break;
 194         PARA_DEBUG_LOG("%d:%s\n", argc, argv[1]);
 195         if (!senders[i].name)
 196                 return -E_COMMAND_SYNTAX;
 197         scd->sender_num = i;
 198         for (i = 0; subcmds[i]; i++)
 199                 if (!strcmp(subcmds[i], argv[2]))
 200                         break;
 201         if (!subcmds[i])
 202                 return -E_COMMAND_SYNTAX;
 203         scd->cmd_num = i;
 204         mmd_lock();
 205         if (!senders[scd->sender_num].client_cmds[scd->cmd_num]) {
 206                 mmd_unlock();
 207                 return -E_SENDER_CMD;
 208         }
 209         mmd_unlock();
 210         switch (scd->cmd_num) {
 211         case SENDER_ON:
 212         case SENDER_OFF:
 213                 if (argc != 3)
 214                         return -E_COMMAND_SYNTAX;
 215                 break;
 216         case SENDER_DENY:
 217         case SENDER_ALLOW:
 218                 if (argc != 4 && argc != 5)
 219                         return -E_COMMAND_SYNTAX;
 220                 if (!inet_aton(argv[3], &scd->addr))
 221                         return -E_COMMAND_SYNTAX;
 222                 scd->netmask = 32;
 223                 if (argc == 5) {
 224                         scd->netmask = atoi(argv[4]);
 225                         if (scd->netmask < 0 || scd->netmask > 32)
 226                                 return -E_COMMAND_SYNTAX;
 227                 }
 228                 break;
 229         case SENDER_ADD:
 230         case SENDER_DELETE:
 231                 if (argc != 4 && argc != 5)
 232                         return -E_COMMAND_SYNTAX;
 233                 if (!inet_aton(argv[3], &scd->addr))
 234                         return -E_COMMAND_SYNTAX;
 235                 scd->port = -1;
 236                 if (argc == 5) {
 237                         scd->port = atoi(argv[4]);
 238                         if (scd->port < 0 || scd->port > 65535)
 239                                 return -E_COMMAND_SYNTAX;
 240                 }
 241                 break;
 242         default:
 243                 return -E_COMMAND_SYNTAX;
 244         }
 245         return 1;
 246 }
 247
 248 int com_sender(int fd, int argc, char * const * argv)
 249 {
 250         int i, ret;
 251         struct sender_command_data scd;
 252
 253         if (argc < 2) {
 254                 char *msg = NULL;
 255                 for (i = 0; senders[i].name; i++) {
 256                         char *tmp = make_message("%s%s\n",
 257                                 msg? msg : "", senders[i].name);
 258                         free(msg);
 259                         msg = tmp;
 260                 }
 261                 ret = send_buffer(fd, msg);
 262                 free(msg);
 263                 return ret;
 264         }
 265         ret = check_sender_args(argc, argv, &scd);
 266         if (ret < 0) {
 267                 char *msg;
 268                 if (scd.sender_num < 0)
 269                         return ret;
 270                 msg = senders[scd.sender_num].help();
 271                 send_buffer(fd, msg);
 272                 free(msg);
 273                 return 1;
 274         }
 275         for (i = 0; i < 10; i++) {
 276                 mmd_lock();
 277                 if (mmd->sender_cmd_data.cmd_num >= 0) {
 278                         mmd_unlock();
 279                         usleep(100 * 1000);
 280                         continue;
 281                 }
 282                 mmd->sender_cmd_data = scd;
 283                 mmd_unlock();
 284                 break;
 285         }
 286         return (i < 10)? 1 : -E_LOCK;
 287 }
 288
 289 /* server info */
 290 int com_si(int fd, int argc, __a_unused char * const * argv)
 291 {
 292         int i, ret;
 293         char *ut;
 294         char *selector_string = NULL, *sender_info = NULL, *sender_list = NULL;
 295
 296         if (argc != 1)
 297                 return -E_COMMAND_SYNTAX;
 298         mmd_lock();
 299         for (i = 0; selectors[i].name; i++) {
 300                 selector_string = para_strcat(selector_string, selectors[i].name);
 301                 selector_string = para_strcat(selector_string, " ");
 302         }
 303         for (i = 0; senders[i].name; i++) {
 304                 char *info = senders[i].info();
 305                 sender_info = para_strcat(sender_info, info);
 306                 free(info);
 307                 sender_list = para_strcat(sender_list, senders[i].name);
 308                 sender_list = para_strcat(sender_list, " ");
 309         }
 310         ut = uptime_str();
 311         ret = send_va_buffer(fd, "up: %s\nplayed: %u\n"
 312                 "pid: %d\n"
 313                 "connections (active/accepted/total): %u/%u/%u\n"
 314                 "current loglevel: %i\n"
 315                 "supported audio file selectors: %s\n"
 316                 "supported audio formats: %s\n"
 317                 "supported senders: %s\n"
 318                 "%s",
 319                 ut, mmd->num_played,
 320                 getppid(),
 321                 mmd->active_connections,
 322                 mmd->num_commands,
 323                 mmd->num_connects,
 324                 conf.loglevel_arg,
 325                 selector_string,
 326                 supported_audio_formats(),
 327                 sender_list,
 328                 sender_info
 329         );
 330         mmd_unlock();
 331         free(ut);
 332         free(selector_string);
 333         free(sender_list);
 334         free(sender_info);
 335         return ret;
 336 }
 337
 338 /* version */
 339 int com_version(int fd, int argc, __a_unused char * const * argv)
 340 {
 341         if (argc != 1)
 342                 return -E_COMMAND_SYNTAX;
 343         return send_buffer(fd, VERSION_TEXT("server")
 344                 "built: " BUILD_DATE "\n"
 345                 SYSTEM ", " CC_VERSION "\n"
 346         );
 347 }
 348
 349 /* sc */
 350 int com_sc(int fd, int argc, char * const * argv)
 351 {
 352         char *name = NULL;
 353         int ret, old = 0, count = -1; /* print af change forever */
 354
 355         if (argc > 1)
 356                 count = atoi(argv[1]);
 357 repeat:
 358         mmd_lock();
 359         if (old != mmd->num_played) {
 360                 old = mmd->num_played;
 361                 name = para_strdup(mmd->filename);
 362         }
 363         mmd_unlock();
 364         if (name) {
 365                 ret = send_va_buffer(fd, "%s\n", name);
 366                 free(name);
 367                 name = NULL;
 368                 if (ret < 0)
 369                         return ret;
 370                 if (argc > 1 && !--count)
 371                         return 1;
 372         }
 373         usleep(500000);
 374         goto repeat;
 375 }
 376
 377 /* sb */
 378 int com_sb(int fd, int argc, char * const * argv)
 379 {
 380         char *sb;
 381         int ret, nr = -1;       /* status bar will be printed that many
 382                                  * times. Negative value means: print
 383                                  * forever
 384                                  */
 385         if (argc > 1)
 386                 nr = atoi(argv[1]);
 387         while (nr) {
 388                 mmd_lock();
 389                 sb = get_sb_string(mmd);
 390                 mmd_unlock();
 391                 ret = send_va_buffer(fd, "%s\n", sb);
 392                 free(sb);
 393                 if (ret < 0)
 394                         return ret;
 395                 if (nr == 1)
 396                         return 1;
 397                 usleep(500000);
 398                 if (nr > 0)
 399                         nr--;
 400         }
 401         return 1;
 402 }
 403
 404 /* stat */
 405 int com_stat(int fd, int argc, char * const * argv)
 406 {
 407         int ret, num = 0;/* status will be printed that many
 408                           * times. num <= 0 means: print forever
 409                           */
 410         struct misc_meta_data tmp, *nmmd = &tmp;
 411         char *s;
 412
 413         signal(SIGUSR1, dummy);
 414
 415         if (argc > 1)
 416                 num = atoi(argv[1]);
 417         for (;;) {
 418
 419                 mmd_dup(nmmd);
 420                 s = get_status(nmmd);
 421                 ret = send_buffer(fd, s);
 422                 free(s);
 423                 if (ret < 0)
 424                         goto out;
 425                 ret = 1;
 426                 if (num == 1)
 427                         goto out;
 428                 sleep(50);
 429                 if (getppid() == 1)
 430                         return -E_SERVER_CRASH;
 431         }
 432 out:
 433         return ret;
 434 }
 435
 436 static int send_list_of_commands(int fd, struct server_command *cmd,
 437                 const char *handler)
 438 {
 439         int ret, i;
 440
 441         for (i = 1; cmd->name; cmd++, i++) {
 442                 char *perms = cmd_perms_itohuman(cmd->perms);
 443                 ret = send_va_buffer(fd, "%s\t%s\t%s\t%s\n", cmd->name,
 444                         handler,
 445                         perms,
 446                         cmd->description);
 447                 free(perms);
 448                 if (ret < 0)
 449                         return ret;
 450         }
 451         return 1;
 452 }
 453
 454 /* always returns string that must be freed by the caller in handler */
 455 static struct server_command *get_cmd_ptr(const char *name, char **handler)
 456 {
 457         struct server_command *cmd;
 458
 459         for (cmd = server_cmds; cmd->name; cmd++)
 460                 if (!strcmp(cmd->name, name)) {
 461                         if (handler)
 462                                 *handler = para_strdup("para_server"); /* server commands */
 463                         return cmd;
 464                 }
 465         /* not found, look for commands supported by the current selector */
 466         mmd_lock();
 467         if (handler)
 468                 *handler = make_message("the %s selector",
 469                         selectors[mmd->selector_num].name);
 470         cmd = selectors[mmd->selector_num].cmd_list;
 471         mmd_unlock();
 472         for (; cmd->name; cmd++)
 473                 if (!strcmp(cmd->name, name))
 474                         return cmd;
 475         /* not found, look for commands supported by afs */
 476         for (cmd = afs_cmds; cmd; cmd++)
 477                 if (!strcmp(cmd->name, name))
 478                         return cmd;
 479         return NULL;
 480 }
 481
 482 /* help */
 483 int com_help(int fd, int argc, char * const * argv)
 484 {
 485         struct server_command *cmd;
 486         char *perms, *handler;
 487         int ret;
 488
 489         if (argc < 2) {
 490                 /* no argument given, print list of commands */
 491                 if ((ret = send_list_of_commands(fd, server_cmds, "server")) < 0)
 492                         return ret;
 493                 mmd_lock();
 494                 handler = para_strdup(selectors[mmd->selector_num].name);
 495                 cmd = selectors[mmd->selector_num].cmd_list;
 496                 mmd_unlock();
 497                 ret = send_list_of_commands(fd, cmd, handler);
 498                 free(handler);
 499                 if (ret < 0)
 500                         return ret;
 501                 cmd = afs_cmds;
 502                 ret = send_list_of_commands(fd, cmd, "afs");
 503         }
 504         /* argument given for help */
 505         cmd = get_cmd_ptr(argv[1], &handler);
 506         if (!cmd) {
 507                 free(handler);
 508                 return -E_BAD_CMD;
 509         }
 510         perms = cmd_perms_itohuman(cmd->perms);
 511         ret = send_va_buffer(fd,
 512                 "%s - %s\n\n"
 513                 "handler: %s\n"
 514                 "permissions: %s\n"
 515                 "usage: %s\n\n"
 516                 "%s\n",
 517                 argv[1],
 518                 cmd->description,
 519                 handler,
 520                 perms,
 521                 cmd->usage,
 522                 cmd->help
 523         );
 524         free(perms);
 525         free(handler);
 526         return ret;
 527 }
 528
 529 /* hup */
 530 int com_hup(__a_unused int fd, int argc, __a_unused char * const * argv)
 531 {
 532         if (argc != 1)
 533                 return -E_COMMAND_SYNTAX;
 534         kill(getppid(), SIGHUP);
 535         return 1;
 536 }
 537
 538 /* term */
 539 int com_term(__a_unused int fd, int argc, __a_unused char * const * argv)
 540 {
 541         if (argc != 1)
 542                 return -E_COMMAND_SYNTAX;
 543         kill(getppid(), SIGTERM);
 544         return 1;
 545 }
 546
 547 int com_play(__a_unused int fd, int argc, __a_unused char * const * argv)
 548 {
 549         if (argc != 1)
 550                 return -E_COMMAND_SYNTAX;
 551         mmd_lock();
 552         mmd->new_vss_status_flags |= VSS_PLAYING;
 553         mmd->new_vss_status_flags &= ~VSS_NOMORE;
 554         mmd_unlock();
 555         return 1;
 556
 557 }
 558
 559 /* stop */
 560 int com_stop(__a_unused int fd, int argc, __a_unused char * const * argv)
 561 {
 562         if (argc != 1)
 563                 return -E_COMMAND_SYNTAX;
 564         mmd_lock();
 565         mmd->new_vss_status_flags &= ~VSS_PLAYING;
 566         mmd->new_vss_status_flags &= ~VSS_REPOS;
 567         mmd->new_vss_status_flags |= VSS_NEXT;
 568         mmd_unlock();
 569         return 1;
 570 }
 571
 572 /* pause */
 573 int com_pause(__a_unused int fd, int argc, __a_unused char * const * argv)
 574 {
 575         if (argc != 1)
 576                 return -E_COMMAND_SYNTAX;
 577         mmd_lock();
 578         if (!vss_paused())
 579                 mmd->events++;
 580         mmd->new_vss_status_flags &= ~VSS_PLAYING;
 581         mmd->new_vss_status_flags &= ~VSS_NEXT;
 582         mmd_unlock();
 583         return 1;
 584 }
 585
 586 int com_chs(int fd, int argc, char * const * argv)
 587 {
 588         int i, ret;
 589
 590         if (argc == 1) {
 591                 char *selector;
 592                 mmd_lock();
 593                 selector = para_strdup(selectors[mmd->selector_num].name);
 594                 mmd_unlock();
 595                 ret = send_va_buffer(fd, "%s\n", selector);
 596                 free(selector);
 597                 return ret;
 598         }
 599         for (i = 0; selectors[i].name; i++) {
 600                 if (strcmp(selectors[i].name, argv[1]))
 601                         continue;
 602                 mmd_lock();
 603                 mmd->selector_change = i;
 604                 mmd->events++;
 605                 mmd_unlock();
 606                 return 1;
 607         }
 608         return -E_BAD_SELECTOR;
 609 }
 610
 611 /* next */
 612 int com_next(__a_unused int fd, int argc, __a_unused char * const * argv)
 613 {
 614         if (argc != 1)
 615                 return -E_COMMAND_SYNTAX;
 616         mmd_lock();
 617         mmd->events++;
 618         mmd->new_vss_status_flags |= VSS_NEXT;
 619         mmd_unlock();
 620         return 1;
 621 }
 622
 623 /* nomore */
 624 int com_nomore(__a_unused int fd, int argc, __a_unused char * const * argv)
 625 {
 626         if (argc != 1)
 627                 return -E_COMMAND_SYNTAX;
 628         mmd_lock();
 629         if (vss_playing() || vss_paused())
 630                 mmd->new_vss_status_flags |= VSS_NOMORE;
 631         mmd_unlock();
 632         return 1;
 633 }
 634
 635 /* ff */
 636 int com_ff(__a_unused int fd, int argc, char * const * argv)
 637 {
 638         long promille;
 639         int ret, backwards = 0;
 640         unsigned i;
 641         char c;
 642
 643         if (argc != 2)
 644                 return -E_COMMAND_SYNTAX;
 645         if (!(ret = sscanf(argv[1], "%u%c", &i, &c)))
 646                 return -E_COMMAND_SYNTAX;
 647         if (ret > 1 && c == '-')
 648                 backwards = 1; /* jmp backwards */
 649         mmd_lock();
 650         ret = -E_NO_AUDIO_FILE;
 651         if (!mmd->afi.chunks_total || !mmd->afi.seconds_total)
 652                 goto out;
 653         promille = (1000 * mmd->current_chunk) / mmd->afi.chunks_total;
 654         if (backwards)
 655                 promille -= 1000 * i / mmd->afi.seconds_total;
 656         else
 657                 promille += 1000 * i / mmd->afi.seconds_total;
 658         if (promille < 0)
 659                 promille = 0;
 660         if (promille >  1000) {
 661                 mmd->new_vss_status_flags |= VSS_NEXT;
 662                 goto out;
 663         }
 664         mmd->repos_request = (mmd->afi.chunks_total * promille) / 1000;
 665         mmd->new_vss_status_flags |= VSS_REPOS;
 666         mmd->new_vss_status_flags &= ~VSS_NEXT;
 667         mmd->events++;
 668         ret = 1;
 669 out:
 670         mmd_unlock();
 671         return ret;
 672 }
 673
 674 /* jmp */
 675 int com_jmp(__a_unused int fd, int argc, char * const * argv)
 676 {
 677         long unsigned int i;
 678         int ret;
 679
 680         if (argc != 2)
 681                 return -E_COMMAND_SYNTAX;
 682         if (sscanf(argv[1], "%lu", &i) <= 0)
 683                 return -E_COMMAND_SYNTAX;
 684         mmd_lock();
 685         ret = -E_NO_AUDIO_FILE;
 686         if (!mmd->afi.chunks_total)
 687                 goto out;
 688         if (i > 100)
 689                 i = 100;
 690         PARA_INFO_LOG("jumping to %lu%%\n", i);
 691         mmd->repos_request = (mmd->afi.chunks_total * i + 50)/ 100;
 692         PARA_INFO_LOG("sent: %lu,  offset before jmp: %lu\n",
 693                 mmd->chunks_sent, mmd->offset);
 694         mmd->new_vss_status_flags |= VSS_REPOS;
 695         mmd->new_vss_status_flags &= ~VSS_NEXT;
 696         ret = 1;
 697         mmd->events++;
 698 out:
 699         mmd_unlock();
 700         return ret;
 701 }
 702
 703 /*
 704  * check if perms are sufficient to exec a command having perms cmd_perms.
 705  * Returns 0 if perms are sufficient, -E_PERM otherwise.
 706  */
 707 static int check_perms(unsigned int perms, struct server_command *cmd_ptr)
 708 {
 709         PARA_DEBUG_LOG("%s", "checking permissions\n");
 710         return (cmd_ptr->perms & perms) < cmd_ptr->perms ? -E_PERM : 0;
 711 }
 712
 713 /*
 714  * Parse first string from *cmd and lookup in table of valid commands.
 715  * On error, NULL is returned.
 716  */
 717 static struct server_command *parse_cmd(const char *cmdstr)
 718 {
 719         char buf[255];
 720         int n = 0;
 721
 722         sscanf(cmdstr, "%200s%n", buf, &n);
 723         if (!n)
 724                 return NULL;
 725         buf[n] = '\0';
 726         return get_cmd_ptr(buf, NULL);
 727 }
 728
 729 static long int para_rand(long unsigned max)
 730 {
 731         return (long int) ((max + 0.0) * (random() / (RAND_MAX + 1.0)));
 732 }
 733
 734 static void init_rc4_keys(void)
 735 {
 736         int i;
 737
 738         for (i = 0; i < 2 * RC4_KEY_LEN; i++)
 739                 rc4_buf[i] = para_rand(256);
 740         PARA_DEBUG_LOG("rc4 keys initialized (%u:%u)\n",
 741                 (unsigned char) rc4_buf[0],
 742                 (unsigned char) rc4_buf[RC4_KEY_LEN]);
 743         RC4_set_key(&rc4_recv_key, RC4_KEY_LEN, rc4_buf);
 744         RC4_set_key(&rc4_send_key, RC4_KEY_LEN, rc4_buf + RC4_KEY_LEN);
 745 }
 746
 747 static void rc4_recv(unsigned long len, const unsigned char *indata,
 748                 unsigned char *outdata, __a_unused void *private_data)
 749 {
 750         RC4(&rc4_recv_key, len, indata, outdata);
 751 }
 752
 753 static void rc4_send(unsigned long len, const unsigned char *indata,
 754                 unsigned char *outdata, __a_unused void *private_data)
 755 {
 756         RC4(&rc4_send_key, len, indata, outdata);
 757 }
 758
 759 static int read_command(int fd, char **result)
 760 {
 761         int ret;
 762         char buf[4096];
 763         char *command = NULL;
 764
 765         for (;;) {
 766                 size_t numbytes;
 767                 char *p;
 768
 769                 ret = recv_buffer(fd, buf, sizeof(buf));
 770                 if (ret < 0)
 771                         goto out;
 772                 if (!ret)
 773                         break;
 774                 numbytes = ret;
 775                 ret = -E_COMMAND_SYNTAX;
 776                 if (command && numbytes + strlen(command) > MAX_COMMAND_LEN) /* DOS */
 777                         goto out;
 778                 command = para_strcat(command, buf);
 779                 p = strstr(command, EOC_MSG);
 780                 if (p) {
 781                         *p = '\0';
 782                         break;
 783                 }
 784         }
 785         ret = command? 1 : -E_COMMAND_SYNTAX;
 786 out:
 787         if (ret < 0)
 788                 free(command);
 789         else
 790                 *result = command;
 791         return ret;
 792
 793 }
 794
 795 /**
 796  * perform user authentication and execute a command
 797  *
 798  * \param fd the file descriptor to send output to
 799  * \param addr socket address info of peer
 800  *
 801  * \return EXIT_SUCCESS or EXIT_FAILURE
 802  *
 803  * Whenever para_server accepts an incoming tcp connection on
 804  * the port it listens on, it forks and the resulting child
 805  * calls this function.
 806  *
 807  * An RSA-based challenge/response is used to authenticate
 808  * the peer. It that authentication succeeds, a random RC4
 809  * session key is generated and sent back to the peer,
 810  * encrypted with its RSA public key.  From this point on,
 811  * all transfers are crypted with this session key.
 812  *
 813  * Next it is checked if the peer supplied  a valid server
 814  * command or a command for the audio file selector currently
 815  * in use.  If yes, and if the user has sufficient
 816  * permissions to execute that command, the function calls
 817  * the corresponding command handler which does argument
 818  * checking and further processing.
 819  *
 820  * In order to cope with a DOS attacks, a timeout is set up
 821  * which terminates the function if the connection was not
 822  * authenticated when the timeout expires.
 823  *
 824  * \sa alarm(2), rc4(3), crypt.c, crypt.h
 825  */
 826 int handle_connect(int fd, struct sockaddr_in *addr)
 827 {
 828         int ret, argc, use_rc4 = 0;
 829         char buf[4096];
 830         unsigned char crypt_buf[MAXLINE];
 831         struct user *u;
 832         struct server_command *cmd = NULL;
 833         long unsigned challenge_nr, chall_response;
 834         char **argv = NULL;
 835         char *p, *command = NULL;
 836         size_t numbytes;
 837
 838         signal(SIGCHLD, SIG_IGN);
 839         signal(SIGINT, SIG_DFL);
 840         signal(SIGTERM, SIG_DFL);
 841         signal(SIGHUP, SIG_DFL);
 842         signal(SIGUSR1, SIG_IGN);
 843
 844         challenge_nr = random();
 845         /* send Welcome message */
 846         ret = send_va_buffer(fd, "This is para_server, version "
 847                 PACKAGE_VERSION  ".\n" );
 848         if (ret < 0)
 849                 goto err_out;
 850         /* recv auth request line */
 851         ret = recv_buffer(fd, buf, sizeof(buf));
 852         if (ret < 0)
 853                 goto err_out;
 854         if (ret <= 6) {
 855                 ret = -E_AUTH;
 856                 goto err_out;
 857         }
 858         numbytes = ret;
 859         ret = -E_AUTH;
 860         if (strncmp(buf, "auth ", 5))
 861                 goto err_out;
 862
 863         if (numbytes < 9 || strncmp(buf, "auth rc4 ", 9))
 864                 p = buf + 5; /* client version < 0.2.6 */
 865         else {
 866                 p = buf + 9; /* client version >= 0.2.6 */
 867                 use_rc4 = 1;
 868         }
 869         PARA_DEBUG_LOG("received %s request for user %s\n",
 870                 use_rc4? "rc4" : "auth", p);
 871         ret = -E_BAD_USER;
 872         u = lookup_user(p);
 873         if (!u)
 874                 goto err_out;
 875         ret = para_encrypt_challenge(u->rsa, challenge_nr, crypt_buf);
 876         if (ret <= 0)
 877                 goto err_out;
 878         numbytes = ret;
 879         PARA_DEBUG_LOG("sending %zu byte challenge\n", numbytes);
 880         /* We can't use send_buffer here since buf may contain null bytes */
 881         ret = send_bin_buffer(fd,(char *) crypt_buf, numbytes);
 882         if (ret < 0)
 883                 goto err_out;
 884         /* recv decrypted number */
 885         ret = recv_buffer(fd, buf, sizeof(buf));
 886         if (ret < 0)
 887                 goto err_out;
 888         numbytes = ret;
 889         ret = -E_AUTH;
 890         if (!numbytes)
 891                 goto err_out;
 892         if (sscanf(buf, CHALLENGE_RESPONSE_MSG "%lu", &chall_response) < 1
 893                         || chall_response != challenge_nr)
 894                 goto err_out;
 895         /* auth successful, send 'Proceed' message */
 896         PARA_INFO_LOG("good auth for %s (%lu)\n", u->name, challenge_nr);
 897         sprintf(buf, "%s", PROCEED_MSG);
 898         if (use_rc4) {
 899                 init_rc4_keys();
 900                 ret = para_encrypt_buffer(u->rsa, rc4_buf, 2 * RC4_KEY_LEN,
 901                         (unsigned char *)buf + PROCEED_MSG_LEN + 1);
 902                 if (ret <= 0)
 903                         goto err_out;
 904                 numbytes = ret + strlen(PROCEED_MSG) + 1;
 905         } else
 906                 numbytes = strlen(buf);
 907         ret = send_bin_buffer(fd, buf, numbytes);
 908         if (ret < 0)
 909                 goto err_out;
 910         if (use_rc4)
 911                 enable_crypt(fd, rc4_recv, rc4_send, NULL);
 912         ret = read_command(fd, &command);
 913         if (ret < 0)
 914                 goto err_out;
 915         ret = -E_BAD_CMD;
 916         cmd = parse_cmd(command);
 917         if (!cmd)
 918                 goto err_out;
 919         /* valid command, check permissions */
 920         ret = check_perms(u->perms, cmd);
 921         if (ret < 0)
 922                 goto err_out;
 923         /* valid command and sufficient perms */
 924         alarm(0);
 925         argc = split_args(command, &argv, "\n");
 926         mmd_lock();
 927         mmd->num_commands++;
 928         mmd_unlock();
 929         PARA_NOTICE_LOG("calling com_%s() for %s@%s\n", cmd->name, u->name,
 930                 inet_ntoa(addr->sin_addr));
 931         ret = cmd->handler(fd, argc, argv);
 932         if (ret >= 0) {
 933                 ret = EXIT_SUCCESS;
 934                 goto out;
 935         }
 936 err_out:
 937         PARA_NOTICE_LOG("%s\n", PARA_STRERROR(-ret));
 938         if (ret != -E_SEND && ret != -E_RECV)
 939                 send_va_buffer(fd, "%s\n", PARA_STRERROR(-ret));
 940         ret = EXIT_FAILURE;
 941 out:
 942         free(command);
 943         free(argv);
 944         mmd_lock();
 945         if (cmd && (cmd->perms & AFS_WRITE) && ret >= 0)
 946                 mmd->events++;
 947         mmd->active_connections--;
 948         mmd_unlock();
 949         return ret;
 950 }