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