command.c

   1 /*
   2  * Copyright (C) 1997-2007 Andre Noll <maan@systemlinux.org>
   3  *
   4  *     This program is free software; you can redistribute it and/or modify
   5  *     it under the terms of the GNU General Public License as published by
   6  *     the Free Software Foundation; either version 2 of the License, or
   7  *     (at your option) any later version.
   8  *
   9  *     This program is distributed in the hope that it will be useful,
  10  *     but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  *     GNU General Public License for more details.
  13  *
  14  *     You should have received a copy of the GNU General Public License
  15  *     along with this program; if not, write to the Free Software
  16  *     Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111, USA.
  17  */
  18
  19 /** \file command.c does client authentication and executes server commands */
  20
  21 #include <sys/time.h> /* gettimeofday */
  22 #include "server.cmdline.h"
  23 #include "db.h"
  24 #include "server.h"
  25 #include "vss.h"
  26 #include "send.h"
  27 #include "rc4.h"
  28 #include <openssl/rc4.h>
  29 #include "error.h"
  30 #include "net.h"
  31 #include "daemon.h"
  32 #include "string.h"
  33 #include "fd.h"
  34 #include "user_list.h"
  35 #include "server_command_list.h"
  36
  37 static RC4_KEY rc4_recv_key;
  38 static RC4_KEY rc4_send_key;
  39 static unsigned char rc4_buf[2 * RC4_KEY_LEN];
  40
  41 extern const char *status_item_list[NUM_STAT_ITEMS];
  42 extern struct misc_meta_data *mmd;
  43 extern struct audio_file_selector selectors[];
  44 extern struct sender senders[];
  45 extern char *user_list;
  46
  47 static void dummy(__a_unused int s)
  48 {}
  49
  50 static void mmd_dup(struct misc_meta_data *new_mmd)
  51 {
  52         mmd_lock();
  53         *new_mmd = *mmd;
  54         mmd_unlock();
  55 }
  56
  57 /*
  58  * compute human readable string containing
  59  * vss status for given integer value
  60  */
  61 static char *vss_status_tohuman(unsigned int flags)
  62 {
  63         if (flags & VSS_PLAYING)
  64                 return para_strdup("playing");
  65         else if (flags & VSS_NEXT)
  66                 return para_strdup("stopped");
  67         else
  68                 return para_strdup("paused");
  69 }
  70
  71 /*
  72  * return human readable permission string. Never returns NULL.
  73  */
  74 static char *cmd_perms_itohuman(unsigned int perms)
  75 {
  76         char *msg = para_malloc(5 * sizeof(char));
  77
  78         msg[0] = perms & DB_READ? 'a' : '-';
  79         msg[1] = perms & DB_WRITE? 'A' : '-';
  80         msg[2] = perms & VSS_READ? 'v' : '-';
  81         msg[3] = perms & VSS_WRITE? 'V' : '-';
  82         msg[4] = '\0';
  83         return msg;
  84 }
  85
  86 /*
  87  * Never returns NULL.
  88  */
  89 static char *vss_get_status_flags(unsigned int flags)
  90 {
  91         char *msg = para_malloc(5 * sizeof(char));
  92
  93         msg[0] = (flags & VSS_PLAYING)? 'P' : '_';
  94         msg[1] = (flags & VSS_NOMORE)? 'O' : '_';
  95         msg[2] = (flags & VSS_NEXT)? 'N' : '_';
  96         msg[3] = (flags & VSS_REPOS)? 'R' : '_';
  97         msg[4] = '\0';
  98         return msg;
  99 }
 100
 101 /*
 102  * compute status bar string. Never returns NULL
 103  */
 104 static char *get_sb_string(struct misc_meta_data *nmmd)
 105 {
 106         char *base, *ret;
 107         long long unsigned secs = 0, rsecs = 0, percent = 0;
 108
 109         base = para_basename(nmmd->filename);
 110         if (!base)
 111                 return para_strdup("");
 112         if (!base[0])
 113                 return base;
 114         if (nmmd->chunks_total) {
 115                 secs = (long long) nmmd->seconds_total * nmmd->chunks_sent
 116                         / nmmd->chunks_total;
 117                 rsecs = (long long) nmmd->seconds_total *
 118                         (nmmd->chunks_total - nmmd->chunks_sent)
 119                         / nmmd->chunks_total;
 120                 percent = 100 * ((nmmd->chunks_sent + 5) / 10)
 121                         / ((nmmd->chunks_total + 5) / 10);
 122         }
 123         ret = make_message("%llu:%02llu [%llu:%02llu] (%llu%%) %s",
 124                 secs / 60, secs % 60,
 125                 rsecs / 60, rsecs % 60,
 126                 percent,
 127                 base
 128         );
 129         free(base);
 130         return ret;
 131 }
 132
 133 static char *get_status(struct misc_meta_data *nmmd)
 134 {
 135         char *bar, *ret, mtime[30] = "";
 136         char *status, *flags; /* vss status info */
 137         char *ut = uptime_str();
 138         long offset = (nmmd->offset + 500) / 1000;
 139         struct timeval now;
 140         struct tm mtime_tm;
 141
 142         if (nmmd->audio_format >= 0) {
 143                 localtime_r(&nmmd->mtime, &mtime_tm);
 144                 strftime(mtime, 29, "%a %b %d %Y", &mtime_tm);
 145         }
 146         /* report real status */
 147         status = vss_status_tohuman(nmmd->vss_status_flags);
 148         flags = vss_get_status_flags(nmmd->vss_status_flags);
 149         bar = para_basename(nmmd->filename);
 150         gettimeofday(&now, NULL);
 151         ret = make_message(
 152                 "%s:%lu\n"      "%s:%s\n"               "%s:%i\n"       "%s:%u\n"
 153                 "%s:%s\n"       "%s:%s\n"       "%s:%s\n"       "%s:%s\n"
 154                 "%s:%li\n"      "%s:%s\n"       "%s"            "%s"
 155                 "%s:%s\n"       "%s:%lu.%lu\n"  "%s:%lu.%lu\n",
 156                 status_item_list[SI_FILE_SIZE], nmmd->size / 1024,
 157                 status_item_list[SI_MTIME], mtime,
 158                 status_item_list[SI_LENGTH], nmmd->seconds_total,
 159                 status_item_list[SI_NUM_PLAYED], nmmd->num_played,
 160
 161                 status_item_list[SI_STATUS_BAR], bar ? bar : "(none)",
 162                 status_item_list[SI_STATUS], status,
 163                 status_item_list[SI_STATUS_FLAGS], flags,
 164                 status_item_list[SI_SELECTOR], selectors[nmmd->selector_num].name,
 165
 166                 status_item_list[SI_OFFSET], offset,
 167                 status_item_list[SI_FORMAT], audio_format_name(nmmd->audio_format),
 168                 nmmd->selector_info,
 169                 nmmd->audio_file_info,
 170
 171                 status_item_list[SI_UPTIME], ut,
 172                 status_item_list[SI_STREAM_START],
 173                         (long unsigned)nmmd->stream_start.tv_sec,
 174                         (long unsigned)nmmd->stream_start.tv_usec,
 175                 status_item_list[SI_CURRENT_TIME],
 176                         (long unsigned)now.tv_sec,
 177                         (long unsigned)now.tv_usec
 178
 179         );
 180         free(bar);
 181         free(flags);
 182         free(status);
 183         free(ut);
 184         return ret;
 185 }
 186
 187 static int check_sender_args(int argc, char **argv, struct sender_command_data *scd)
 188 {
 189         int i;
 190         /* this has to match sender.h */
 191         const char *subcmds[] = {"add", "delete", "allow", "deny", "on", "off", NULL};
 192
 193         scd->sender_num = -1;
 194         if (argc < 2)
 195                 return -E_COMMAND_SYNTAX;
 196         for (i = 0; senders[i].name; i++)
 197                 if (!strcmp(senders[i].name, argv[1]))
 198                         break;
 199         PARA_DEBUG_LOG("%d:%s\n", argc, argv[1]);
 200         if (!senders[i].name)
 201                 return -E_COMMAND_SYNTAX;
 202         scd->sender_num = i;
 203         for (i = 0; subcmds[i]; i++)
 204                 if (!strcmp(subcmds[i], argv[2]))
 205                         break;
 206         if (!subcmds[i])
 207                 return -E_COMMAND_SYNTAX;
 208         scd->cmd_num = i;
 209         mmd_lock();
 210         if (!senders[scd->sender_num].client_cmds[scd->cmd_num]) {
 211                 mmd_unlock();
 212                 return -E_SENDER_CMD;
 213         }
 214         mmd_unlock();
 215         switch (scd->cmd_num) {
 216         case SENDER_ON:
 217         case SENDER_OFF:
 218                 if (argc != 3)
 219                         return -E_COMMAND_SYNTAX;
 220                 break;
 221         case SENDER_DENY:
 222         case SENDER_ALLOW:
 223                 if (argc != 4 && argc != 5)
 224                         return -E_COMMAND_SYNTAX;
 225                 if (!inet_aton(argv[3], &scd->addr))
 226                         return -E_COMMAND_SYNTAX;
 227                 scd->netmask = 32;
 228                 if (argc == 5) {
 229                         scd->netmask = atoi(argv[4]);
 230                         if (scd->netmask < 0 || scd->netmask > 32)
 231                                 return -E_COMMAND_SYNTAX;
 232                 }
 233                 break;
 234         case SENDER_ADD:
 235         case SENDER_DELETE:
 236                 if (argc != 4 && argc != 5)
 237                         return -E_COMMAND_SYNTAX;
 238                 if (!inet_aton(argv[3], &scd->addr))
 239                         return -E_COMMAND_SYNTAX;
 240                 scd->port = -1;
 241                 if (argc == 5) {
 242                         scd->port = atoi(argv[4]);
 243                         if (scd->port < 0 || scd->port > 65535)
 244                                 return -E_COMMAND_SYNTAX;
 245                 }
 246                 break;
 247         default:
 248                 return -E_COMMAND_SYNTAX;
 249         }
 250         return 1;
 251 }
 252
 253 int com_sender(int fd, int argc, char **argv)
 254 {
 255         int i, ret;
 256         struct sender_command_data scd;
 257
 258         if (argc < 2) {
 259                 char *msg = NULL;
 260                 for (i = 0; senders[i].name; i++) {
 261                         char *tmp = make_message("%s%s\n",
 262                                 msg? msg : "", senders[i].name);
 263                         free(msg);
 264                         msg = tmp;
 265                 }
 266                 ret = send_buffer(fd, msg);
 267                 free(msg);
 268                 return ret;
 269         }
 270         ret = check_sender_args(argc, argv, &scd);
 271         if (ret < 0) {
 272                 char *msg;
 273                 if (scd.sender_num < 0)
 274                         return ret;
 275                 msg = senders[scd.sender_num].help();
 276                 send_buffer(fd, msg);
 277                 free(msg);
 278                 return 1;
 279         }
 280         for (i = 0; i < 10; i++) {
 281                 mmd_lock();
 282                 if (mmd->sender_cmd_data.cmd_num >= 0) {
 283                         mmd_unlock();
 284                         usleep(100 * 1000);
 285                         continue;
 286                 }
 287                 mmd->sender_cmd_data = scd;
 288                 mmd_unlock();
 289                 break;
 290         }
 291         return (i < 10)? 1 : -E_LOCK;
 292 }
 293
 294 /* server info */
 295 int com_si(int fd, int argc, __a_unused char **argv)
 296 {
 297         int i, ret;
 298         char *ut;
 299         char *selector_string = NULL, *sender_info = NULL, *sender_list = NULL;
 300
 301         if (argc != 1)
 302                 return -E_COMMAND_SYNTAX;
 303         mmd_lock();
 304         for (i = 0; selectors[i].name; i++) {
 305                 selector_string = para_strcat(selector_string, selectors[i].name);
 306                 selector_string = para_strcat(selector_string, " ");
 307         }
 308         for (i = 0; senders[i].name; i++) {
 309                 char *info = senders[i].info();
 310                 sender_info = para_strcat(sender_info, info);
 311                 free(info);
 312                 sender_list = para_strcat(sender_list, senders[i].name);
 313                 sender_list = para_strcat(sender_list, " ");
 314         }
 315         ut = uptime_str();
 316         ret = send_va_buffer(fd, "up: %s\nplayed: %u\n"
 317                 "pid: %d\n"
 318                 "connections (active/accepted/total): %u/%u/%u\n"
 319                 "current loglevel: %i\n"
 320                 "supported audio file selectors: %s\n"
 321                 "supported audio formats: %s\n"
 322                 "supported senders: %s\n"
 323                 "%s",
 324                 ut, mmd->num_played,
 325                 getppid(),
 326                 mmd->active_connections,
 327                 mmd->num_commands,
 328                 mmd->num_connects,
 329                 conf.loglevel_arg,
 330                 selector_string,
 331                 supported_audio_formats(),
 332                 sender_list,
 333                 sender_info
 334         );
 335         mmd_unlock();
 336         free(ut);
 337         free(selector_string);
 338         free(sender_list);
 339         free(sender_info);
 340         return ret;
 341 }
 342
 343 /* version */
 344 int com_version(int socket_fd, int argc, __a_unused char **argv)
 345 {
 346         if (argc != 1)
 347                 return -E_COMMAND_SYNTAX;
 348         return send_buffer(socket_fd, VERSION_TEXT("server")
 349                 "built: " BUILD_DATE "\n"
 350                 SYSTEM ", " CC_VERSION "\n"
 351         );
 352 }
 353
 354 /* sc */
 355 int com_sc(int socket_fd, int argc, char **argv)
 356 {
 357         char *name = NULL;
 358         int ret, old = 0, count = -1; /* print af change forever */
 359
 360         if (argc > 1)
 361                 count = atoi(argv[1]);
 362 repeat:
 363         mmd_lock();
 364         if (old != mmd->num_played) {
 365                 old = mmd->num_played;
 366                 name = para_strdup(mmd->filename);
 367         }
 368         mmd_unlock();
 369         if (name) {
 370                 ret = send_va_buffer(socket_fd, "%s\n", name);
 371                 free(name);
 372                 name = NULL;
 373                 if (ret < 0)
 374                         return ret;
 375                 if (argc > 1 && !--count)
 376                         return 1;
 377         }
 378         usleep(500000);
 379         goto repeat;
 380 }
 381
 382 /* sb */
 383 int com_sb(int socket_fd, int argc, char **argv)
 384 {
 385         char *sb;
 386         int ret, nr = -1;       /* status bar will be printed that many
 387                                  * times. Negative value means: print
 388                                  * forever
 389                                  */
 390         if (argc > 1)
 391                 nr = atoi(argv[1]);
 392         while (nr) {
 393                 mmd_lock();
 394                 sb = get_sb_string(mmd);
 395                 mmd_unlock();
 396                 ret = send_va_buffer(socket_fd, "%s\n", sb);
 397                 free(sb);
 398                 if (ret < 0)
 399                         return ret;
 400                 if (nr == 1)
 401                         return 1;
 402                 usleep(500000);
 403                 if (nr > 0)
 404                         nr--;
 405         }
 406         return 1;
 407 }
 408
 409 /* stat */
 410 int com_stat(int socket_fd, int argc, char **argv)
 411 {
 412         int ret, num = 0;/* status will be printed that many
 413                           * times. num <= 0 means: print forever
 414                           */
 415         struct misc_meta_data tmp, *nmmd = &tmp;
 416         char *s;
 417
 418         signal(SIGUSR1, dummy);
 419
 420         if (argc > 1)
 421                 num = atoi(argv[1]);
 422         for (;;) {
 423
 424                 mmd_dup(nmmd);
 425                 s = get_status(nmmd);
 426                 ret = send_buffer(socket_fd, s);
 427                 free(s);
 428                 if (ret < 0)
 429                         goto out;
 430                 ret = 1;
 431                 if (num == 1)
 432                         goto out;
 433                 sleep(50);
 434                 if (getppid() == 1)
 435                         return -E_SERVER_CRASH;
 436         }
 437 out:
 438         return ret;
 439 }
 440
 441 static int send_list_of_commands(int fd, struct server_command *cmd,
 442                 const char *handler)
 443 {
 444         int ret, i;
 445
 446         for (i = 1; cmd->name; cmd++, i++) {
 447                 char *perms = cmd_perms_itohuman(cmd->perms);
 448                 ret = send_va_buffer(fd, "%s\t%s\t%s\t%s\n", cmd->name,
 449                         handler,
 450                         perms,
 451                         cmd->description);
 452                 free(perms);
 453                 if (ret < 0)
 454                         return ret;
 455         }
 456         return 1;
 457 }
 458
 459 /* always returns string that must be freed by the caller in handler */
 460 static struct server_command *get_cmd_ptr(char *name, char **handler)
 461 {
 462         struct server_command *cmd;
 463
 464         for (cmd = server_cmds; cmd->name; cmd++)
 465                 if (!strcmp(cmd->name, name)) {
 466                         if (handler)
 467                                 *handler = para_strdup("para_server"); /* server commands */
 468                         return cmd;
 469                 }
 470         /* not found, look for commands supported by the current selector */
 471         mmd_lock();
 472         if (handler)
 473                 *handler = make_message("the %s selector",
 474                         selectors[mmd->selector_num].name);
 475         cmd = selectors[mmd->selector_num].cmd_list;
 476         mmd_unlock();
 477         for (; cmd->name; cmd++)
 478                 if (!strcmp(cmd->name, name))
 479                         return cmd;
 480         return NULL;
 481 }
 482
 483 /* help */
 484 int com_help(int fd, int argc, char **argv)
 485 {
 486         struct server_command *cmd;
 487         char *perms, *handler;
 488         int ret;
 489
 490         if (argc < 2) {
 491                 /* no argument given, print list of commands */
 492                 if ((ret = send_list_of_commands(fd, server_cmds, "server")) < 0)
 493                         return ret;
 494                 mmd_lock();
 495                 handler = para_strdup(selectors[mmd->selector_num].name);
 496                 cmd = selectors[mmd->selector_num].cmd_list;
 497                 mmd_unlock();
 498                 ret = send_list_of_commands(fd, cmd, handler);
 499                 free(handler);
 500                 return ret;
 501         }
 502         /* argument given for help */
 503         cmd = get_cmd_ptr(argv[1], &handler);
 504         if (!cmd) {
 505                 free(handler);
 506                 return -E_BAD_CMD;
 507         }
 508         perms = cmd_perms_itohuman(cmd->perms);
 509         ret = send_va_buffer(fd,
 510                 "%s - %s\n\n"
 511                 "handler: %s\n"
 512                 "permissions: %s\n"
 513                 "usage: %s\n\n"
 514                 "%s\n",
 515                 argv[1],
 516                 cmd->description,
 517                 handler,
 518                 perms,
 519                 cmd->usage,
 520                 cmd->help
 521         );
 522         free(perms);
 523         free(handler);
 524         return ret;
 525 }
 526
 527 /* hup */
 528 int com_hup(__a_unused int socket_fd, int argc, __a_unused char **argv)
 529 {
 530         if (argc != 1)
 531                 return -E_COMMAND_SYNTAX;
 532         kill(getppid(), SIGHUP);
 533         return 1;
 534 }
 535
 536 /* term */
 537 int com_term(__a_unused int socket_fd, int argc, __a_unused char **argv)
 538 {
 539         if (argc != 1)
 540                 return -E_COMMAND_SYNTAX;
 541         kill(getppid(), SIGTERM);
 542         return 1;
 543 }
 544
 545 int com_play(__a_unused int socket_fd, int argc, __a_unused char **argv)
 546 {
 547         if (argc != 1)
 548                 return -E_COMMAND_SYNTAX;
 549         mmd_lock();
 550         mmd->new_vss_status_flags |= VSS_PLAYING;
 551         mmd->new_vss_status_flags &= ~VSS_NOMORE;
 552         mmd_unlock();
 553         return 1;
 554
 555 }
 556
 557 /* stop */
 558 int com_stop(__a_unused int socket_fd, int argc, __a_unused char **argv)
 559 {
 560         if (argc != 1)
 561                 return -E_COMMAND_SYNTAX;
 562         mmd_lock();
 563         mmd->new_vss_status_flags &= ~VSS_PLAYING;
 564         mmd->new_vss_status_flags &= ~VSS_REPOS;
 565         mmd->new_vss_status_flags |= VSS_NEXT;
 566         mmd_unlock();
 567         return 1;
 568 }
 569
 570 /* pause */
 571 int com_pause(__a_unused int socket_fd, int argc, __a_unused char **argv)
 572 {
 573         if (argc != 1)
 574                 return -E_COMMAND_SYNTAX;
 575         mmd_lock();
 576         if (!vss_paused())
 577                 mmd->events++;
 578         mmd->new_vss_status_flags &= ~VSS_PLAYING;
 579         mmd->new_vss_status_flags &= ~VSS_NEXT;
 580         mmd_unlock();
 581         return 1;
 582 }
 583
 584 int com_chs(int fd, int argc, char **argv)
 585 {
 586         int i, ret;
 587
 588         if (argc == 1) {
 589                 char *selector;
 590                 mmd_lock();
 591                 selector = para_strdup(selectors[mmd->selector_num].name);
 592                 mmd_unlock();
 593                 ret = send_va_buffer(fd, "%s\n", selector);
 594                 free(selector);
 595                 return ret;
 596         }
 597         for (i = 0; selectors[i].name; i++) {
 598                 if (strcmp(selectors[i].name, argv[1]))
 599                         continue;
 600                 mmd_lock();
 601                 mmd->selector_change = i;
 602                 mmd->events++;
 603                 mmd_unlock();
 604                 return 1;
 605         }
 606         return -E_BAD_SELECTOR;
 607 }
 608
 609 /* next */
 610 int com_next(__a_unused int socket_fd, int argc, __a_unused char **argv)
 611 {
 612         if (argc != 1)
 613                 return -E_COMMAND_SYNTAX;
 614         mmd_lock();
 615         mmd->events++;
 616         mmd->new_vss_status_flags |= VSS_NEXT;
 617         mmd_unlock();
 618         return 1;
 619 }
 620
 621 /* nomore */
 622 int com_nomore(__a_unused int socket_fd, int argc, __a_unused char **argv)
 623 {
 624         if (argc != 1)
 625                 return -E_COMMAND_SYNTAX;
 626         mmd_lock();
 627         if (vss_playing() || vss_paused())
 628                 mmd->new_vss_status_flags |= VSS_NOMORE;
 629         mmd_unlock();
 630         return 1;
 631 }
 632
 633 /* ff */
 634 int com_ff(__a_unused int socket_fd, int argc, char **argv)
 635 {
 636         long promille;
 637         int ret, backwards = 0;
 638         unsigned i;
 639         char c;
 640
 641         if (argc != 2)
 642                 return -E_COMMAND_SYNTAX;
 643         if (!(ret = sscanf(argv[1], "%u%c", &i, &c)))
 644                 return -E_COMMAND_SYNTAX;
 645         if (ret > 1 && c == '-')
 646                 backwards = 1; /* jmp backwards */
 647         mmd_lock();
 648         ret = -E_NO_AUDIO_FILE;
 649         if (!mmd->chunks_total || !mmd->seconds_total)
 650                 goto out;
 651         promille = (1000 * mmd->current_chunk) / mmd->chunks_total;
 652         if (backwards)
 653                 promille -= 1000 * i / mmd->seconds_total;
 654         else
 655                 promille += 1000 * i / mmd->seconds_total;
 656         if (promille < 0)
 657                 promille = 0;
 658         if (promille >  1000) {
 659                 mmd->new_vss_status_flags |= VSS_NEXT;
 660                 goto out;
 661         }
 662         mmd->repos_request = (mmd->chunks_total * promille) / 1000;
 663         mmd->new_vss_status_flags |= VSS_REPOS;
 664         mmd->new_vss_status_flags &= ~VSS_NEXT;
 665         mmd->events++;
 666         ret = 1;
 667 out:
 668         mmd_unlock();
 669         return ret;
 670 }
 671
 672 /* jmp */
 673 int com_jmp(__a_unused int socket_fd, int argc, char **argv)
 674 {
 675         long unsigned int i;
 676         int ret;
 677
 678         if (argc != 2)
 679                 return -E_COMMAND_SYNTAX;
 680         if (sscanf(argv[1], "%lu", &i) <= 0)
 681                 return -E_COMMAND_SYNTAX;
 682         mmd_lock();
 683         ret = -E_NO_AUDIO_FILE;
 684         if (!mmd->chunks_total)
 685                 goto out;
 686         if (i > 100)
 687                 i = 100;
 688         PARA_INFO_LOG("jumping to %lu%%\n", i);
 689         mmd->repos_request = (mmd->chunks_total * i + 50)/ 100;
 690         PARA_INFO_LOG("sent: %lu,  offset before jmp: %lu\n",
 691                 mmd->chunks_sent, mmd->offset);
 692         mmd->new_vss_status_flags |= VSS_REPOS;
 693         mmd->new_vss_status_flags &= ~VSS_NEXT;
 694         ret = 1;
 695         mmd->events++;
 696 out:
 697         mmd_unlock();
 698         return ret;
 699 }
 700
 701 /*
 702  * check if perms are sufficient to exec a command having perms cmd_perms.
 703  * Returns 0 if perms are sufficient, -E_PERM otherwise.
 704  */
 705 static int check_perms(unsigned int perms, struct server_command *cmd_ptr)
 706 {
 707         PARA_DEBUG_LOG("%s", "checking permissions\n");
 708         return (cmd_ptr->perms & perms) < cmd_ptr->perms ? -E_PERM : 0;
 709 }
 710
 711 /*
 712  * Parse first string from *cmd and lookup in table of valid commands.
 713  * On error, NULL is returned.
 714  */
 715 static struct server_command *parse_cmd(const char *cmdstr)
 716 {
 717         char buf[255];
 718         int n = 0;
 719
 720         sscanf(cmdstr, "%200s%n", buf, &n);
 721         if (!n)
 722                 return NULL;
 723         buf[n] = '\0';
 724         return get_cmd_ptr(buf, NULL);
 725 }
 726
 727 static long int para_rand(long unsigned max)
 728 {
 729         return (long int) ((max + 0.0) * (random() / (RAND_MAX + 1.0)));
 730 }
 731
 732 static void init_rc4_keys(void)
 733 {
 734         int i;
 735
 736         for (i = 0; i < 2 * RC4_KEY_LEN; i++)
 737                 rc4_buf[i] = para_rand(256);
 738         PARA_DEBUG_LOG("rc4 keys initialized (%u:%u)\n",
 739                 (unsigned char) rc4_buf[0],
 740                 (unsigned char) rc4_buf[RC4_KEY_LEN]);
 741         RC4_set_key(&rc4_recv_key, RC4_KEY_LEN, rc4_buf);
 742         RC4_set_key(&rc4_send_key, RC4_KEY_LEN, rc4_buf + RC4_KEY_LEN);
 743 }
 744
 745 static void rc4_recv(unsigned long len, const unsigned char *indata,
 746                 unsigned char *outdata, __a_unused void *private_data)
 747 {
 748         RC4(&rc4_recv_key, len, indata, outdata);
 749 }
 750
 751 static void rc4_send(unsigned long len, const unsigned char *indata,
 752                 unsigned char *outdata, __a_unused void *private_data)
 753 {
 754         RC4(&rc4_send_key, len, indata, outdata);
 755 }
 756
 757 /**
 758  * perform user authentication and execute a command
 759  *
 760  * \param fd the file descriptor to send output to
 761  * \param addr socket address info of peer
 762  *
 763  * \return EXIT_SUCCESS or EXIT_FAILURE
 764  *
 765  * Whenever para_server accepts an incoming tcp connection on
 766  * the port it listens on, it forks and the resulting child
 767  * calls this function.
 768  *
 769  * An RSA-based challenge/response is used to authenticate
 770  * the peer. It that authentication succeeds, a random RC4
 771  * session key is generated and sent back to the peer,
 772  * encrypted with its RSA public key.  From this point on,
 773  * all transfers are crypted with this session key.
 774  *
 775  * Next it is checked if the peer supplied  a valid server
 776  * command or a command for the audio file selector currently
 777  * in use.  If yes, and if the user has sufficient
 778  * permissions to execute that command, the function calls
 779  * the corresponding command handler which does argument
 780  * checking and further processing.
 781  *
 782  * In order to cope with a DOS attacks, a timeout is set up
 783  * which terminates the function if the connection was not
 784  * authenticated when the timeout expires.
 785  *
 786  * \sa alarm(2), rc4(3), crypt.c, crypt.h
 787  */
 788 int handle_connect(int fd, struct sockaddr_in *addr)
 789 {
 790         int numbytes, ret, argc, use_rc4 = 0;
 791         char buf[STRINGSIZE];
 792         unsigned char crypt_buf[MAXLINE];
 793         struct user u;
 794         struct server_command *cmd = NULL;
 795         long unsigned challenge_nr, chall_response;
 796         char **argv = NULL;
 797         char *p, *command = NULL;
 798
 799         signal(SIGCHLD, SIG_IGN);
 800         signal(SIGINT, SIG_DFL);
 801         signal(SIGTERM, SIG_DFL);
 802         signal(SIGHUP, SIG_DFL);
 803         signal(SIGUSR1, SIG_IGN);
 804
 805         challenge_nr = random();
 806         /* send Welcome message */
 807         ret = send_va_buffer(fd, "This is para_server, version "
 808                 PACKAGE_VERSION  ".\n" );
 809         if (ret < 0)
 810                 goto err_out;
 811         /* recv auth request line */
 812         ret = recv_buffer(fd, buf, sizeof(buf));
 813         if (ret < 0)
 814                 goto err_out;
 815         if (ret <= 6) {
 816                 ret = -E_AUTH;
 817                 goto err_out;
 818         }
 819         numbytes = ret;
 820         ret = -E_AUTH;
 821         if (strncmp(buf, "auth ", 5))
 822                 goto err_out;
 823
 824         if (numbytes < 9 || strncmp(buf, "auth rc4 ", 9))
 825                 u.name = para_strdup(buf + 5); /* client version < 0.2.6 */
 826         else {
 827                 u.name = para_strdup(buf + 9); /* client version >= 0.2.6 */
 828                 use_rc4 = 1;
 829         }
 830         PARA_DEBUG_LOG("received %s request for user %s\n",
 831                 use_rc4? "rc4" : "auth", u.name);
 832         if ((ret = lookup_user(&u)) < 0)
 833                 goto err_out;
 834         ret = para_encrypt_challenge(u.rsa, challenge_nr, crypt_buf);
 835         if (ret <= 0)
 836                 goto err_out;
 837         numbytes = ret;
 838         PARA_DEBUG_LOG("sending %d byte challenge\n", numbytes);
 839         /* We can't use send_buffer here since buf may contain null bytes */
 840         ret = send_bin_buffer(fd,(char *) crypt_buf, numbytes);
 841         if (ret < 0)
 842                 goto err_out;
 843         /* recv decrypted number */
 844         numbytes = recv_buffer(fd, buf, sizeof(buf));
 845         ret = numbytes;
 846         if (ret < 0)
 847                 goto err_out;
 848         ret = -E_AUTH;
 849         if (!numbytes)
 850                 goto err_out;
 851         if (sscanf(buf, CHALLENGE_RESPONSE_MSG "%lu", &chall_response) < 1
 852                         || chall_response != challenge_nr)
 853                 goto err_out;
 854         /* auth successful. Send 'Proceed' message */
 855         PARA_INFO_LOG("good auth for %s (%lu)\n", u.name, challenge_nr);
 856         sprintf(buf, "%s", PROCEED_MSG);
 857         if (use_rc4) {
 858                 init_rc4_keys();
 859                 ret = para_encrypt_buffer(u.rsa, rc4_buf, 2 * RC4_KEY_LEN,
 860                         (unsigned char *)buf + PROCEED_MSG_LEN + 1);
 861                 if (ret <= 0)
 862                         goto err_out;
 863                 numbytes = ret + strlen(PROCEED_MSG) + 1;
 864         } else
 865                 numbytes = strlen(buf);
 866         ret = send_bin_buffer(fd, buf, numbytes);
 867         if (ret < 0)
 868                 goto err_out;
 869         if (use_rc4)
 870                 enable_crypt(fd, rc4_recv, rc4_send, NULL);
 871         /* read command */
 872         while ((numbytes = recv_buffer(fd, buf, sizeof(buf))) > 0) {
 873 //              PARA_INFO_LOG("recvd: %s (%d)\n", buf, numbytes);
 874                 ret = -E_COMMAND_SYNTAX;
 875                 if (command && numbytes + strlen(command) > STRINGSIZE) /* DOS */
 876                         goto err_out;
 877                 command = para_strcat(command, buf);
 878                 if ((p = strstr(command, EOC_MSG))) {
 879                         *p = '\0';
 880                         break;
 881                 }
 882         }
 883         ret = numbytes;
 884         if (ret < 0)
 885                 goto err_out;
 886         ret = -E_BAD_CMD;
 887         /* parse command */
 888         if (!(cmd = parse_cmd(command)))
 889                 goto err_out;
 890         /* valid command, check permissions */
 891         ret = check_perms(u.perms, cmd);
 892         if (ret < 0)
 893                 goto err_out;
 894         /* valid command and sufficient perms */
 895         alarm(0);
 896         argc = split_args(command, &argv, "\n");
 897         mmd_lock();
 898         mmd->num_commands++;
 899         mmd_unlock();
 900         PARA_NOTICE_LOG("calling com_%s() for %s@%s\n", cmd->name, u.name,
 901                 inet_ntoa(addr->sin_addr));
 902         ret = cmd->handler(fd, argc, argv);
 903         if (ret >= 0) {
 904                 ret = EXIT_SUCCESS;
 905                 goto out;
 906         }
 907 err_out:
 908         if (ret != -E_SEND && ret != -E_RECV) {
 909                 PARA_NOTICE_LOG("%s\n", PARA_STRERROR(-ret));
 910                 send_va_buffer(fd, "%s\n", PARA_STRERROR(-ret));
 911         }
 912         ret = EXIT_FAILURE;
 913 out:
 914         free(command);
 915         free(argv);
 916         mmd_lock();
 917         if (cmd && (cmd->perms & DB_WRITE) && ret >= 0)
 918                 mmd->events++;
 919         mmd->active_connections--;
 920         mmd_unlock();
 921         return ret;
 922 }