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 <signal.h>
  10 #include <sys/time.h>
  11 #include <sys/types.h>
  12 #include <dirent.h>
  13 #include <openssl/rc4.h>
  14
  15 #include "para.h"
  16 #include "error.h"
  17 #include "server.cmdline.h"
  18 #include "afs_common.h"
  19 #include "string.h"
  20 #include "afh.h"
  21 #include "afs.h"
  22 #include "server.h"
  23 #include "vss.h"
  24 #include "send.h"
  25 #include "rc4.h"
  26 #include "net.h"
  27 #include "daemon.h"
  28 #include "fd.h"
  29 #include "list.h"
  30 #include "user_list.h"
  31 #include "server_command_list.h"
  32 #include "afs_command_list.h"
  33
  34 /** commands including options must be shorter than this */
  35 #define MAX_COMMAND_LEN 32768
  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
  46 static void dummy(__a_unused int s)
  47 {}
  48
  49 static void mmd_dup(struct misc_meta_data *new_mmd)
  50 {
  51         mmd_lock();
  52         *new_mmd = *mmd;
  53         mmd_unlock();
  54 }
  55
  56 /*
  57  * compute human readable string containing
  58  * vss status for given integer value
  59  */
  60 static char *vss_status_tohuman(unsigned int flags)
  61 {
  62         if (flags & VSS_PLAYING)
  63                 return para_strdup("playing");
  64         else if (flags & VSS_NEXT)
  65                 return para_strdup("stopped");
  66         else
  67                 return para_strdup("paused");
  68 }
  69
  70 /*
  71  * return human readable permission string. Never returns NULL.
  72  */
  73 static char *cmd_perms_itohuman(unsigned int perms)
  74 {
  75         char *msg = para_malloc(5 * sizeof(char));
  76
  77         msg[0] = perms & AFS_READ? 'a' : '-';
  78         msg[1] = perms & AFS_WRITE? 'A' : '-';
  79         msg[2] = perms & VSS_READ? 'v' : '-';
  80         msg[3] = perms & VSS_WRITE? 'V' : '-';
  81         msg[4] = '\0';
  82         return msg;
  83 }
  84
  85 /*
  86  * Never returns NULL.
  87  */
  88 static char *vss_get_status_flags(unsigned int flags)
  89 {
  90         char *msg = para_malloc(5 * sizeof(char));
  91
  92         msg[0] = (flags & VSS_PLAYING)? 'P' : '_';
  93         msg[1] = (flags & VSS_NOMORE)? 'O' : '_';
  94         msg[2] = (flags & VSS_NEXT)? 'N' : '_';
  95         msg[3] = (flags & VSS_REPOS)? 'R' : '_';
  96         msg[4] = '\0';
  97         return msg;
  98 }
  99
 100 /*
 101  * compute status bar string. Never returns NULL
 102  */
 103 static char *get_sb_string(struct misc_meta_data *nmmd)
 104 {
 105         char *base, *ret;
 106         long long unsigned secs = 0, rsecs = 0, percent = 0;
 107
 108         base = para_basename(nmmd->filename);
 109         if (!base)
 110                 return para_strdup("");
 111         if (!base[0])
 112                 return base;
 113         if (nmmd->afi.chunks_total) {
 114                 secs = (long long) nmmd->afi.seconds_total * nmmd->chunks_sent
 115                         / nmmd->afi.chunks_total;
 116                 rsecs = (long long) nmmd->afi.seconds_total *
 117                         (nmmd->afi.chunks_total - nmmd->chunks_sent)
 118                         / nmmd->afi.chunks_total;
 119                 percent = 100 * ((nmmd->chunks_sent + 5) / 10)
 120                         / ((nmmd->afi.chunks_total + 5) / 10);
 121         }
 122         ret = make_message("%llu:%02llu [%llu:%02llu] (%llu%%) %s",
 123                 secs / 60, secs % 60,
 124                 rsecs / 60, rsecs % 60,
 125                 percent,
 126                 base
 127         );
 128         free(base);
 129         return ret;
 130 }
 131
 132 static char *get_status(struct misc_meta_data *nmmd)
 133 {
 134         char *bar, *ret, mtime[30] = "";
 135         char *status, *flags; /* vss status info */
 136         char *ut = uptime_str();
 137         long offset = (nmmd->offset + 500) / 1000;
 138         struct timeval now;
 139         struct tm mtime_tm;
 140
 141         if (nmmd->audio_format >= 0) {
 142                 localtime_r(&nmmd->mtime, &mtime_tm);
 143                 strftime(mtime, 29, "%a %b %d %Y", &mtime_tm);
 144         }
 145         /* report real status */
 146         status = vss_status_tohuman(nmmd->vss_status_flags);
 147         flags = vss_get_status_flags(nmmd->vss_status_flags);
 148         bar = para_basename(nmmd->filename);
 149         gettimeofday(&now, NULL);
 150         ret = make_message(
 151                 "%s:%zu\n"      "%s:%s\n"               "%s:%lu\n"      "%s:%u\n"
 152                 "%s:%s\n"       "%s:%s\n"       "%s:%s\n"       "%s:%s\n"
 153                 "%s:%li\n"      "%s:%s\n"       "%s"            "%s"
 154                 "%s:%s\n"       "%s:%lu.%lu\n"  "%s:%lu.%lu\n",
 155                 status_item_list[SI_FILE_SIZE], nmmd->size / 1024,
 156                 status_item_list[SI_MTIME], mtime,
 157                 status_item_list[SI_LENGTH], nmmd->afi.seconds_total,
 158                 status_item_list[SI_NUM_PLAYED], nmmd->num_played,
 159
 160                 status_item_list[SI_STATUS_BAR], bar ? bar : "(none)",
 161                 status_item_list[SI_STATUS], status,
 162                 status_item_list[SI_STATUS_FLAGS], flags,
 163                 status_item_list[SI_SELECTOR], selectors[nmmd->selector_num].name,
 164
 165                 status_item_list[SI_OFFSET], offset,
 166                 status_item_list[SI_FORMAT], audio_format_name(nmmd->audio_format),
 167                 nmmd->selector_info,
 168                 nmmd->afi.info_string,
 169
 170                 status_item_list[SI_UPTIME], ut,
 171                 status_item_list[SI_STREAM_START],
 172                         (long unsigned)nmmd->stream_start.tv_sec,
 173                         (long unsigned)nmmd->stream_start.tv_usec,
 174                 status_item_list[SI_CURRENT_TIME],
 175                         (long unsigned)now.tv_sec,
 176                         (long unsigned)now.tv_usec
 177
 178         );
 179         free(bar);
 180         free(flags);
 181         free(status);
 182         free(ut);
 183         return ret;
 184 }
 185
 186 static int check_sender_args(int argc, char * const * argv, struct sender_command_data *scd)
 187 {
 188         int i;
 189         /* this has to match sender.h */
 190         const char *subcmds[] = {"add", "delete", "allow", "deny", "on", "off", NULL};
 191
 192         scd->sender_num = -1;
 193         if (argc < 2)
 194                 return -E_COMMAND_SYNTAX;
 195         for (i = 0; senders[i].name; i++)
 196                 if (!strcmp(senders[i].name, argv[1]))
 197                         break;
 198         PARA_DEBUG_LOG("%d:%s\n", argc, argv[1]);
 199         if (!senders[i].name)
 200                 return -E_COMMAND_SYNTAX;
 201         scd->sender_num = i;
 202         for (i = 0; subcmds[i]; i++)
 203                 if (!strcmp(subcmds[i], argv[2]))
 204                         break;
 205         if (!subcmds[i])
 206                 return -E_COMMAND_SYNTAX;
 207         scd->cmd_num = i;
 208         mmd_lock();
 209         if (!senders[scd->sender_num].client_cmds[scd->cmd_num]) {
 210                 mmd_unlock();
 211                 return -E_SENDER_CMD;
 212         }
 213         mmd_unlock();
 214         switch (scd->cmd_num) {
 215         case SENDER_ON:
 216         case SENDER_OFF:
 217                 if (argc != 3)
 218                         return -E_COMMAND_SYNTAX;
 219                 break;
 220         case SENDER_DENY:
 221         case SENDER_ALLOW:
 222                 if (argc != 4 && argc != 5)
 223                         return -E_COMMAND_SYNTAX;
 224                 if (!inet_pton(AF_INET, argv[3], &scd->addr))
 225                         return -E_COMMAND_SYNTAX;
 226                 scd->netmask = 32;
 227                 if (argc == 5) {
 228                         scd->netmask = atoi(argv[4]);
 229                         if (scd->netmask < 0 || scd->netmask > 32)
 230                                 return -E_COMMAND_SYNTAX;
 231                 }
 232                 break;
 233         case SENDER_ADD:
 234         case SENDER_DELETE:
 235                 if (argc != 4 && argc != 5)
 236                         return -E_COMMAND_SYNTAX;
 237                 if (!inet_pton(AF_INET, argv[3], &scd->addr))
 238                         return -E_COMMAND_SYNTAX;
 239                 scd->port = -1;
 240                 if (argc == 5) {
 241                         scd->port = atoi(argv[4]);
 242                         if (scd->port < 0 || scd->port > 65535)
 243                                 return -E_COMMAND_SYNTAX;
 244                 }
 245                 break;
 246         default:
 247                 return -E_COMMAND_SYNTAX;
 248         }
 249         return 1;
 250 }
 251
 252 int com_sender(int fd, int argc, char * const * argv)
 253 {
 254         int i, ret;
 255         struct sender_command_data scd;
 256
 257         if (argc < 2) {
 258                 char *msg = NULL;
 259                 for (i = 0; senders[i].name; i++) {
 260                         char *tmp = make_message("%s%s\n",
 261                                 msg? msg : "", senders[i].name);
 262                         free(msg);
 263                         msg = tmp;
 264                 }
 265                 ret = send_buffer(fd, msg);
 266                 free(msg);
 267                 return ret;
 268         }
 269         ret = check_sender_args(argc, argv, &scd);
 270         if (ret < 0) {
 271                 char *msg;
 272                 if (scd.sender_num < 0)
 273                         return ret;
 274                 msg = senders[scd.sender_num].help();
 275                 send_buffer(fd, msg);
 276                 free(msg);
 277                 return 1;
 278         }
 279         for (i = 0; i < 10; i++) {
 280                 mmd_lock();
 281                 if (mmd->sender_cmd_data.cmd_num >= 0) {
 282                         mmd_unlock();
 283                         usleep(100 * 1000);
 284                         continue;
 285                 }
 286                 mmd->sender_cmd_data = scd;
 287                 mmd_unlock();
 288                 break;
 289         }
 290         return (i < 10)? 1 : -E_LOCK;
 291 }
 292
 293 /* server info */
 294 int com_si(int fd, int argc, __a_unused char * const * argv)
 295 {
 296         int i, ret;
 297         char *ut;
 298         char *selector_string = NULL, *sender_info = NULL, *sender_list = NULL;
 299
 300         if (argc != 1)
 301                 return -E_COMMAND_SYNTAX;
 302         mmd_lock();
 303         for (i = 0; selectors[i].name; i++) {
 304                 selector_string = para_strcat(selector_string, selectors[i].name);
 305                 selector_string = para_strcat(selector_string, " ");
 306         }
 307         for (i = 0; senders[i].name; i++) {
 308                 char *info = senders[i].info();
 309                 sender_info = para_strcat(sender_info, info);
 310                 free(info);
 311                 sender_list = para_strcat(sender_list, senders[i].name);
 312                 sender_list = para_strcat(sender_list, " ");
 313         }
 314         ut = uptime_str();
 315         ret = send_va_buffer(fd, "up: %s\nplayed: %u\n"
 316                 "pid: %d\n"
 317                 "connections (active/accepted/total): %u/%u/%u\n"
 318                 "current loglevel: %i\n"
 319                 "supported audio file selectors: %s\n"
 320                 "supported audio formats: %s\n"
 321                 "supported senders: %s\n"
 322                 "%s",
 323                 ut, mmd->num_played,
 324                 getppid(),
 325                 mmd->active_connections,
 326                 mmd->num_commands,
 327                 mmd->num_connects,
 328                 conf.loglevel_arg,
 329                 selector_string,
 330                 supported_audio_formats(),
 331                 sender_list,
 332                 sender_info
 333         );
 334         mmd_unlock();
 335         free(ut);
 336         free(selector_string);
 337         free(sender_list);
 338         free(sender_info);
 339         return ret;
 340 }
 341
 342 /* version */
 343 int com_version(int fd, int argc, __a_unused char * const * argv)
 344 {
 345         if (argc != 1)
 346                 return -E_COMMAND_SYNTAX;
 347         return send_buffer(fd, VERSION_TEXT("server")
 348                 "built: " BUILD_DATE "\n"
 349                 SYSTEM ", " CC_VERSION "\n"
 350         );
 351 }
 352
 353 /* sc */
 354 int com_sc(int fd, int argc, char * const * argv)
 355 {
 356         char *name = NULL;
 357         int ret, old = 0, count = -1; /* print af change forever */
 358
 359         if (argc > 1)
 360                 count = atoi(argv[1]);
 361 repeat:
 362         mmd_lock();
 363         if (old != mmd->num_played) {
 364                 old = mmd->num_played;
 365                 name = para_strdup(mmd->filename);
 366         }
 367         mmd_unlock();
 368         if (name) {
 369                 ret = send_va_buffer(fd, "%s\n", name);
 370                 free(name);
 371                 name = NULL;
 372                 if (ret < 0)
 373                         return ret;
 374                 if (argc > 1 && !--count)
 375                         return 1;
 376         }
 377         usleep(500000);
 378         goto repeat;
 379 }
 380
 381 /* sb */
 382 int com_sb(int fd, int argc, char * const * argv)
 383 {
 384         char *sb;
 385         int ret, nr = -1;       /* status bar will be printed that many
 386                                  * times. Negative value means: print
 387                                  * forever
 388                                  */
 389         if (argc > 1)
 390                 nr = atoi(argv[1]);
 391         while (nr) {
 392                 mmd_lock();
 393                 sb = get_sb_string(mmd);
 394                 mmd_unlock();
 395                 ret = send_va_buffer(fd, "%s\n", sb);
 396                 free(sb);
 397                 if (ret < 0)
 398                         return ret;
 399                 if (nr == 1)
 400                         return 1;
 401                 usleep(500000);
 402                 if (nr > 0)
 403                         nr--;
 404         }
 405         return 1;
 406 }
 407
 408 /* stat */
 409 int com_stat(int fd, int argc, char * const * argv)
 410 {
 411         int ret, num = 0;/* status will be printed that many
 412                           * times. num <= 0 means: print forever
 413                           */
 414         struct misc_meta_data tmp, *nmmd = &tmp;
 415         char *s;
 416
 417         signal(SIGUSR1, dummy);
 418
 419         if (argc > 1)
 420                 num = atoi(argv[1]);
 421         for (;;) {
 422
 423                 mmd_dup(nmmd);
 424                 s = get_status(nmmd);
 425                 ret = send_buffer(fd, s);
 426                 free(s);
 427                 if (ret < 0)
 428                         goto out;
 429                 ret = 1;
 430                 if (num == 1)
 431                         goto out;
 432                 sleep(50);
 433                 if (getppid() == 1)
 434                         return -E_SERVER_CRASH;
 435         }
 436 out:
 437         return ret;
 438 }
 439
 440 static int send_list_of_commands(int fd, struct server_command *cmd,
 441                 const char *handler)
 442 {
 443         int ret, i;
 444
 445         for (i = 1; cmd->name; cmd++, i++) {
 446                 char *perms = cmd_perms_itohuman(cmd->perms);
 447                 ret = send_va_buffer(fd, "%s\t%s\t%s\t%s\n", cmd->name,
 448                         handler,
 449                         perms,
 450                         cmd->description);
 451                 free(perms);
 452                 if (ret < 0)
 453                         return ret;
 454         }
 455         return 1;
 456 }
 457
 458 /* always returns string that must be freed by the caller in handler */
 459 static struct server_command *get_cmd_ptr(const char *name, char **handler)
 460 {
 461         struct server_command *cmd;
 462
 463         for (cmd = server_cmds; cmd->name; cmd++)
 464                 if (!strcmp(cmd->name, name)) {
 465                         if (handler)
 466                                 *handler = para_strdup("para_server"); /* server commands */
 467                         return cmd;
 468                 }
 469         /* not found, look for commands supported by the current selector */
 470         mmd_lock();
 471         if (handler)
 472                 *handler = make_message("the %s selector",
 473                         selectors[mmd->selector_num].name);
 474         cmd = selectors[mmd->selector_num].cmd_list;
 475         mmd_unlock();
 476         for (; cmd->name; cmd++)
 477                 if (!strcmp(cmd->name, name))
 478                         return cmd;
 479         /* not found, look for commands supported by afs */
 480         for (cmd = afs_cmds; cmd->name; cmd++)
 481                 if (!strcmp(cmd->name, name))
 482                         return cmd;
 483         return NULL;
 484 }
 485
 486 /* help */
 487 int com_help(int fd, int argc, char * const * argv)
 488 {
 489         struct server_command *cmd;
 490         char *perms, *handler;
 491         int ret;
 492
 493         if (argc < 2) {
 494                 /* no argument given, print list of commands */
 495                 if ((ret = send_list_of_commands(fd, server_cmds, "server")) < 0)
 496                         return ret;
 497                 mmd_lock();
 498                 handler = para_strdup(selectors[mmd->selector_num].name);
 499                 cmd = selectors[mmd->selector_num].cmd_list;
 500                 mmd_unlock();
 501                 ret = send_list_of_commands(fd, cmd, handler);
 502                 free(handler);
 503                 if (ret < 0)
 504                         return ret;
 505                 cmd = afs_cmds;
 506                 return send_list_of_commands(fd, cmd, "afs");
 507         }
 508         /* argument given for help */
 509         cmd = get_cmd_ptr(argv[1], &handler);
 510         if (!cmd) {
 511                 free(handler);
 512                 return -E_BAD_CMD;
 513         }
 514         perms = cmd_perms_itohuman(cmd->perms);
 515         ret = send_va_buffer(fd,
 516                 "%s - %s\n\n"
 517                 "handler: %s\n"
 518                 "permissions: %s\n"
 519                 "usage: %s\n\n"
 520                 "%s\n",
 521                 argv[1],
 522                 cmd->description,
 523                 handler,
 524                 perms,
 525                 cmd->usage,
 526                 cmd->help
 527         );
 528         free(perms);
 529         free(handler);
 530         return ret;
 531 }
 532
 533 /* hup */
 534 int com_hup(__a_unused int fd, int argc, __a_unused char * const * argv)
 535 {
 536         if (argc != 1)
 537                 return -E_COMMAND_SYNTAX;
 538         kill(getppid(), SIGHUP);
 539         return 1;
 540 }
 541
 542 /* term */
 543 int com_term(__a_unused int fd, int argc, __a_unused char * const * argv)
 544 {
 545         if (argc != 1)
 546                 return -E_COMMAND_SYNTAX;
 547         kill(getppid(), SIGTERM);
 548         return 1;
 549 }
 550
 551 int com_play(__a_unused int fd, int argc, __a_unused char * const * argv)
 552 {
 553         if (argc != 1)
 554                 return -E_COMMAND_SYNTAX;
 555         mmd_lock();
 556         mmd->new_vss_status_flags |= VSS_PLAYING;
 557         mmd->new_vss_status_flags &= ~VSS_NOMORE;
 558         mmd_unlock();
 559         return 1;
 560
 561 }
 562
 563 /* stop */
 564 int com_stop(__a_unused int fd, int argc, __a_unused char * const * argv)
 565 {
 566         if (argc != 1)
 567                 return -E_COMMAND_SYNTAX;
 568         mmd_lock();
 569         mmd->new_vss_status_flags &= ~VSS_PLAYING;
 570         mmd->new_vss_status_flags &= ~VSS_REPOS;
 571         mmd->new_vss_status_flags |= VSS_NEXT;
 572         mmd_unlock();
 573         return 1;
 574 }
 575
 576 /* pause */
 577 int com_pause(__a_unused int fd, int argc, __a_unused char * const * argv)
 578 {
 579         if (argc != 1)
 580                 return -E_COMMAND_SYNTAX;
 581         mmd_lock();
 582         if (!vss_paused())
 583                 mmd->events++;
 584         mmd->new_vss_status_flags &= ~VSS_PLAYING;
 585         mmd->new_vss_status_flags &= ~VSS_NEXT;
 586         mmd_unlock();
 587         return 1;
 588 }
 589
 590 int com_chs(int fd, int argc, char * const * argv)
 591 {
 592         int i, ret;
 593
 594         if (argc == 1) {
 595                 char *selector;
 596                 mmd_lock();
 597                 selector = para_strdup(selectors[mmd->selector_num].name);
 598                 mmd_unlock();
 599                 ret = send_va_buffer(fd, "%s\n", selector);
 600                 free(selector);
 601                 return ret;
 602         }
 603         for (i = 0; selectors[i].name; i++) {
 604                 if (strcmp(selectors[i].name, argv[1]))
 605                         continue;
 606                 mmd_lock();
 607                 mmd->selector_change = i;
 608                 mmd->events++;
 609                 mmd_unlock();
 610                 return 1;
 611         }
 612         return -E_BAD_SELECTOR;
 613 }
 614
 615 /* next */
 616 int com_next(__a_unused int fd, int argc, __a_unused char * const * argv)
 617 {
 618         if (argc != 1)
 619                 return -E_COMMAND_SYNTAX;
 620         mmd_lock();
 621         mmd->events++;
 622         mmd->new_vss_status_flags |= VSS_NEXT;
 623         mmd_unlock();
 624         return 1;
 625 }
 626
 627 /* nomore */
 628 int com_nomore(__a_unused int fd, int argc, __a_unused char * const * argv)
 629 {
 630         if (argc != 1)
 631                 return -E_COMMAND_SYNTAX;
 632         mmd_lock();
 633         if (vss_playing() || vss_paused())
 634                 mmd->new_vss_status_flags |= VSS_NOMORE;
 635         mmd_unlock();
 636         return 1;
 637 }
 638
 639 /* ff */
 640 int com_ff(__a_unused int fd, int argc, char * const * argv)
 641 {
 642         long promille;
 643         int ret, backwards = 0;
 644         unsigned i;
 645         char c;
 646
 647         if (argc != 2)
 648                 return -E_COMMAND_SYNTAX;
 649         if (!(ret = sscanf(argv[1], "%u%c", &i, &c)))
 650                 return -E_COMMAND_SYNTAX;
 651         if (ret > 1 && c == '-')
 652                 backwards = 1; /* jmp backwards */
 653         mmd_lock();
 654         ret = -E_NO_AUDIO_FILE;
 655         if (!mmd->afi.chunks_total || !mmd->afi.seconds_total)
 656                 goto out;
 657         promille = (1000 * mmd->current_chunk) / mmd->afi.chunks_total;
 658         if (backwards)
 659                 promille -= 1000 * i / mmd->afi.seconds_total;
 660         else
 661                 promille += 1000 * i / mmd->afi.seconds_total;
 662         if (promille < 0)
 663                 promille = 0;
 664         if (promille >  1000) {
 665                 mmd->new_vss_status_flags |= VSS_NEXT;
 666                 goto out;
 667         }
 668         mmd->repos_request = (mmd->afi.chunks_total * promille) / 1000;
 669         mmd->new_vss_status_flags |= VSS_REPOS;
 670         mmd->new_vss_status_flags &= ~VSS_NEXT;
 671         mmd->events++;
 672         ret = 1;
 673 out:
 674         mmd_unlock();
 675         return ret;
 676 }
 677
 678 /* jmp */
 679 int com_jmp(__a_unused int fd, int argc, char * const * argv)
 680 {
 681         long unsigned int i;
 682         int ret;
 683
 684         if (argc != 2)
 685                 return -E_COMMAND_SYNTAX;
 686         if (sscanf(argv[1], "%lu", &i) <= 0)
 687                 return -E_COMMAND_SYNTAX;
 688         mmd_lock();
 689         ret = -E_NO_AUDIO_FILE;
 690         if (!mmd->afi.chunks_total)
 691                 goto out;
 692         if (i > 100)
 693                 i = 100;
 694         PARA_INFO_LOG("jumping to %lu%%\n", i);
 695         mmd->repos_request = (mmd->afi.chunks_total * i + 50)/ 100;
 696         PARA_INFO_LOG("sent: %lu,  offset before jmp: %lu\n",
 697                 mmd->chunks_sent, mmd->offset);
 698         mmd->new_vss_status_flags |= VSS_REPOS;
 699         mmd->new_vss_status_flags &= ~VSS_NEXT;
 700         ret = 1;
 701         mmd->events++;
 702 out:
 703         mmd_unlock();
 704         return ret;
 705 }
 706
 707 /*
 708  * check if perms are sufficient to exec a command having perms cmd_perms.
 709  * Returns 0 if perms are sufficient, -E_PERM otherwise.
 710  */
 711 static int check_perms(unsigned int perms, struct server_command *cmd_ptr)
 712 {
 713         PARA_DEBUG_LOG("%s", "checking permissions\n");
 714         return (cmd_ptr->perms & perms) < cmd_ptr->perms ? -E_PERM : 0;
 715 }
 716
 717 /*
 718  * Parse first string from *cmd and lookup in table of valid commands.
 719  * On error, NULL is returned.
 720  */
 721 static struct server_command *parse_cmd(const char *cmdstr)
 722 {
 723         char buf[255];
 724         int n = 0;
 725
 726         sscanf(cmdstr, "%200s%n", buf, &n);
 727         if (!n)
 728                 return NULL;
 729         buf[n] = '\0';
 730         return get_cmd_ptr(buf, NULL);
 731 }
 732
 733 static long int para_rand(long unsigned max)
 734 {
 735         return (long int) ((max + 0.0) * (random() / (RAND_MAX + 1.0)));
 736 }
 737
 738 static void init_rc4_keys(void)
 739 {
 740         int i;
 741
 742         for (i = 0; i < 2 * RC4_KEY_LEN; i++)
 743                 rc4_buf[i] = para_rand(256);
 744         PARA_DEBUG_LOG("rc4 keys initialized (%u:%u)\n",
 745                 (unsigned char) rc4_buf[0],
 746                 (unsigned char) rc4_buf[RC4_KEY_LEN]);
 747         RC4_set_key(&rc4_recv_key, RC4_KEY_LEN, rc4_buf);
 748         RC4_set_key(&rc4_send_key, RC4_KEY_LEN, rc4_buf + RC4_KEY_LEN);
 749 }
 750
 751 static void rc4_recv(unsigned long len, const unsigned char *indata,
 752                 unsigned char *outdata, __a_unused void *private_data)
 753 {
 754         RC4(&rc4_recv_key, len, indata, outdata);
 755 }
 756
 757 static void rc4_send(unsigned long len, const unsigned char *indata,
 758                 unsigned char *outdata, __a_unused void *private_data)
 759 {
 760         RC4(&rc4_send_key, len, indata, outdata);
 761 }
 762
 763 static int read_command(int fd, char **result)
 764 {
 765         int ret;
 766         char buf[4096];
 767         char *command = NULL;
 768
 769         for (;;) {
 770                 size_t numbytes;
 771                 char *p;
 772
 773                 ret = recv_buffer(fd, buf, sizeof(buf));
 774                 if (ret < 0)
 775                         goto out;
 776                 if (!ret)
 777                         break;
 778                 numbytes = ret;
 779                 ret = -E_COMMAND_SYNTAX;
 780                 if (command && numbytes + strlen(command) > MAX_COMMAND_LEN) /* DOS */
 781                         goto out;
 782                 command = para_strcat(command, buf);
 783                 p = strstr(command, EOC_MSG);
 784                 if (p) {
 785                         *p = '\0';
 786                         break;
 787                 }
 788         }
 789         ret = command? 1 : -E_COMMAND_SYNTAX;
 790 out:
 791         if (ret < 0)
 792                 free(command);
 793         else
 794                 *result = command;
 795         return ret;
 796
 797 }
 798
 799 /**
 800  * perform user authentication and execute a command
 801  *
 802  * \param fd the file descriptor to send output to
 803  * \param addr socket address info of peer
 804  *
 805  * \return EXIT_SUCCESS or EXIT_FAILURE
 806  *
 807  * Whenever para_server accepts an incoming tcp connection on
 808  * the port it listens on, it forks and the resulting child
 809  * calls this function.
 810  *
 811  * An RSA-based challenge/response is used to authenticate
 812  * the peer. It that authentication succeeds, a random RC4
 813  * session key is generated and sent back to the peer,
 814  * encrypted with its RSA public key.  From this point on,
 815  * all transfers are crypted with this session key.
 816  *
 817  * Next it is checked if the peer supplied  a valid server
 818  * command or a command for the audio file selector currently
 819  * in use.  If yes, and if the user has sufficient
 820  * permissions to execute that command, the function calls
 821  * the corresponding command handler which does argument
 822  * checking and further processing.
 823  *
 824  * In order to cope with a DOS attacks, a timeout is set up
 825  * which terminates the function if the connection was not
 826  * authenticated when the timeout expires.
 827  *
 828  * \sa alarm(2), rc4(3), crypt.c, crypt.h
 829  */
 830 int handle_connect(int fd, struct sockaddr_in *addr)
 831 {
 832         int ret, argc, use_rc4 = 0;
 833         char buf[4096];
 834         unsigned char crypt_buf[MAXLINE];
 835         struct user *u;
 836         struct server_command *cmd = NULL;
 837         long unsigned challenge_nr, chall_response;
 838         char **argv = NULL;
 839         char *p, *command = NULL;
 840         size_t numbytes;
 841
 842         signal(SIGCHLD, SIG_IGN);
 843         signal(SIGINT, SIG_DFL);
 844         signal(SIGTERM, SIG_DFL);
 845         signal(SIGHUP, SIG_DFL);
 846         signal(SIGUSR1, SIG_IGN);
 847
 848         challenge_nr = random();
 849         /* send Welcome message */
 850         ret = send_va_buffer(fd, "This is para_server, version "
 851                 PACKAGE_VERSION  ".\n" );
 852         if (ret < 0)
 853                 goto err_out;
 854         /* recv auth request line */
 855         ret = recv_buffer(fd, buf, sizeof(buf));
 856         if (ret < 0)
 857                 goto err_out;
 858         if (ret <= 6) {
 859                 ret = -E_AUTH;
 860                 goto err_out;
 861         }
 862         numbytes = ret;
 863         ret = -E_AUTH;
 864         if (strncmp(buf, "auth ", 5))
 865                 goto err_out;
 866
 867         if (numbytes < 9 || strncmp(buf, "auth rc4 ", 9))
 868                 p = buf + 5; /* client version < 0.2.6 */
 869         else {
 870                 p = buf + 9; /* client version >= 0.2.6 */
 871                 use_rc4 = 1;
 872         }
 873         PARA_DEBUG_LOG("received %s request for user %s\n",
 874                 use_rc4? "rc4" : "auth", p);
 875         ret = -E_BAD_USER;
 876         u = lookup_user(p);
 877         if (!u)
 878                 goto err_out;
 879         ret = para_encrypt_challenge(u->rsa, challenge_nr, crypt_buf);
 880         if (ret <= 0)
 881                 goto err_out;
 882         numbytes = ret;
 883         PARA_DEBUG_LOG("sending %zu byte challenge\n", numbytes);
 884         /* We can't use send_buffer here since buf may contain null bytes */
 885         ret = send_bin_buffer(fd,(char *) crypt_buf, numbytes);
 886         if (ret < 0)
 887                 goto err_out;
 888         /* recv decrypted number */
 889         ret = recv_buffer(fd, buf, sizeof(buf));
 890         if (ret < 0)
 891                 goto err_out;
 892         numbytes = ret;
 893         ret = -E_AUTH;
 894         if (!numbytes)
 895                 goto err_out;
 896         if (sscanf(buf, CHALLENGE_RESPONSE_MSG "%lu", &chall_response) < 1
 897                         || chall_response != challenge_nr)
 898                 goto err_out;
 899         /* auth successful, send 'Proceed' message */
 900         PARA_INFO_LOG("good auth for %s (%lu)\n", u->name, challenge_nr);
 901         sprintf(buf, "%s", PROCEED_MSG);
 902         if (use_rc4) {
 903                 init_rc4_keys();
 904                 ret = para_encrypt_buffer(u->rsa, rc4_buf, 2 * RC4_KEY_LEN,
 905                         (unsigned char *)buf + PROCEED_MSG_LEN + 1);
 906                 if (ret <= 0)
 907                         goto err_out;
 908                 numbytes = ret + strlen(PROCEED_MSG) + 1;
 909         } else
 910                 numbytes = strlen(buf);
 911         ret = send_bin_buffer(fd, buf, numbytes);
 912         if (ret < 0)
 913                 goto err_out;
 914         if (use_rc4)
 915                 enable_crypt(fd, rc4_recv, rc4_send, NULL);
 916         ret = read_command(fd, &command);
 917         if (ret < 0)
 918                 goto err_out;
 919         ret = -E_BAD_CMD;
 920         cmd = parse_cmd(command);
 921         if (!cmd)
 922                 goto err_out;
 923         /* valid command, check permissions */
 924         ret = check_perms(u->perms, cmd);
 925         if (ret < 0)
 926                 goto err_out;
 927         /* valid command and sufficient perms */
 928         alarm(0);
 929         argc = split_args(command, &argv, "\n");
 930         mmd_lock();
 931         mmd->num_commands++;
 932         mmd_unlock();
 933         PARA_NOTICE_LOG("calling com_%s() for %s@%s\n", cmd->name, u->name,
 934                 inet_ntoa(addr->sin_addr));
 935         ret = cmd->handler(fd, argc, argv);
 936         if (ret >= 0) {
 937                 ret = EXIT_SUCCESS;
 938                 goto out;
 939         }
 940 err_out:
 941         PARA_NOTICE_LOG("%s\n", PARA_STRERROR(-ret));
 942         if (ret != -E_SEND && ret != -E_RECV)
 943                 send_va_buffer(fd, "%s\n", PARA_STRERROR(-ret));
 944         ret = EXIT_FAILURE;
 945 out:
 946         free(command);
 947         free(argv);
 948         mmd_lock();
 949         if (cmd && (cmd->perms & AFS_WRITE) && ret >= 0)
 950                 mmd->events++;
 951         mmd->active_connections--;
 952         mmd_unlock();
 953         return ret;
 954 }