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 "server.cmdline.h"
  17 #include "afs_common.h"
  18 #include "afh.h"
  19 #include "server.h"
  20 #include "vss.h"
  21 #include "send.h"
  22 #include "rc4.h"
  23 #include "error.h"
  24 #include "net.h"
  25 #include "daemon.h"
  26 #include "string.h"
  27 #include "fd.h"
  28 #include "list.h"
  29 #include "user_list.h"
  30 #include "server_command_list.h"
  31 #include "afs_command_list.h"
  32
  33 /** commands including options must be shorter than this */
  34 #define MAX_COMMAND_LEN 32768
  35
  36 static RC4_KEY rc4_recv_key;
  37 static RC4_KEY rc4_send_key;
  38 static unsigned char rc4_buf[2 * RC4_KEY_LEN];
  39
  40 extern const char *status_item_list[NUM_STAT_ITEMS];
  41 extern struct misc_meta_data *mmd;
  42 extern struct audio_file_selector selectors[];
  43 extern struct sender senders[];
  44
  45 static void dummy(__a_unused int s)
  46 {}
  47
  48 static void mmd_dup(struct misc_meta_data *new_mmd)
  49 {
  50         mmd_lock();
  51         *new_mmd = *mmd;
  52         mmd_unlock();
  53 }
  54
  55 /*
  56  * compute human readable string containing
  57  * vss status for given integer value
  58  */
  59 static char *vss_status_tohuman(unsigned int flags)
  60 {
  61         if (flags & VSS_PLAYING)
  62                 return para_strdup("playing");
  63         else if (flags & VSS_NEXT)
  64                 return para_strdup("stopped");
  65         else
  66                 return para_strdup("paused");
  67 }
  68
  69 /*
  70  * return human readable permission string. Never returns NULL.
  71  */
  72 static char *cmd_perms_itohuman(unsigned int perms)
  73 {
  74         char *msg = para_malloc(5 * sizeof(char));
  75
  76         msg[0] = perms & AFS_READ? 'a' : '-';
  77         msg[1] = perms & AFS_WRITE? 'A' : '-';
  78         msg[2] = perms & VSS_READ? 'v' : '-';
  79         msg[3] = perms & VSS_WRITE? 'V' : '-';
  80         msg[4] = '\0';
  81         return msg;
  82 }
  83
  84 /*
  85  * Never returns NULL.
  86  */
  87 static char *vss_get_status_flags(unsigned int flags)
  88 {
  89         char *msg = para_malloc(5 * sizeof(char));
  90
  91         msg[0] = (flags & VSS_PLAYING)? 'P' : '_';
  92         msg[1] = (flags & VSS_NOMORE)? 'O' : '_';
  93         msg[2] = (flags & VSS_NEXT)? 'N' : '_';
  94         msg[3] = (flags & VSS_REPOS)? 'R' : '_';
  95         msg[4] = '\0';
  96         return msg;
  97 }
  98
  99 /*
 100  * compute status bar string. Never returns NULL
 101  */
 102 static char *get_sb_string(struct misc_meta_data *nmmd)
 103 {
 104         char *base, *ret;
 105         long long unsigned secs = 0, rsecs = 0, percent = 0;
 106
 107         base = para_basename(nmmd->filename);
 108         if (!base)
 109                 return para_strdup("");
 110         if (!base[0])
 111                 return base;
 112         if (nmmd->afi.chunks_total) {
 113                 secs = (long long) nmmd->afi.seconds_total * nmmd->chunks_sent
 114                         / nmmd->afi.chunks_total;
 115                 rsecs = (long long) nmmd->afi.seconds_total *
 116                         (nmmd->afi.chunks_total - nmmd->chunks_sent)
 117                         / nmmd->afi.chunks_total;
 118                 percent = 100 * ((nmmd->chunks_sent + 5) / 10)
 119                         / ((nmmd->afi.chunks_total + 5) / 10);
 120         }
 121         ret = make_message("%llu:%02llu [%llu:%02llu] (%llu%%) %s",
 122                 secs / 60, secs % 60,
 123                 rsecs / 60, rsecs % 60,
 124                 percent,
 125                 base
 126         );
 127         free(base);
 128         return ret;
 129 }
 130
 131 static char *get_status(struct misc_meta_data *nmmd)
 132 {
 133         char *bar, *ret, mtime[30] = "";
 134         char *status, *flags; /* vss status info */
 135         char *ut = uptime_str();
 136         long offset = (nmmd->offset + 500) / 1000;
 137         struct timeval now;
 138         struct tm mtime_tm;
 139
 140         if (nmmd->audio_format >= 0) {
 141                 localtime_r(&nmmd->mtime, &mtime_tm);
 142                 strftime(mtime, 29, "%a %b %d %Y", &mtime_tm);
 143         }
 144         /* report real status */
 145         status = vss_status_tohuman(nmmd->vss_status_flags);
 146         flags = vss_get_status_flags(nmmd->vss_status_flags);
 147         bar = para_basename(nmmd->filename);
 148         gettimeofday(&now, NULL);
 149         ret = make_message(
 150                 "%s:%zu\n"      "%s:%s\n"               "%s:%lu\n"      "%s:%u\n"
 151                 "%s:%s\n"       "%s:%s\n"       "%s:%s\n"       "%s:%s\n"
 152                 "%s:%li\n"      "%s:%s\n"       "%s"            "%s"
 153                 "%s:%s\n"       "%s:%lu.%lu\n"  "%s:%lu.%lu\n",
 154                 status_item_list[SI_FILE_SIZE], nmmd->size / 1024,
 155                 status_item_list[SI_MTIME], mtime,
 156                 status_item_list[SI_LENGTH], nmmd->afi.seconds_total,
 157                 status_item_list[SI_NUM_PLAYED], nmmd->num_played,
 158
 159                 status_item_list[SI_STATUS_BAR], bar ? bar : "(none)",
 160                 status_item_list[SI_STATUS], status,
 161                 status_item_list[SI_STATUS_FLAGS], flags,
 162                 status_item_list[SI_SELECTOR], selectors[nmmd->selector_num].name,
 163
 164                 status_item_list[SI_OFFSET], offset,
 165                 status_item_list[SI_FORMAT], audio_format_name(nmmd->audio_format),
 166                 nmmd->selector_info,
 167                 nmmd->afi.info_string,
 168
 169                 status_item_list[SI_UPTIME], ut,
 170                 status_item_list[SI_STREAM_START],
 171                         (long unsigned)nmmd->stream_start.tv_sec,
 172                         (long unsigned)nmmd->stream_start.tv_usec,
 173                 status_item_list[SI_CURRENT_TIME],
 174                         (long unsigned)now.tv_sec,
 175                         (long unsigned)now.tv_usec
 176
 177         );
 178         free(bar);
 179         free(flags);
 180         free(status);
 181         free(ut);
 182         return ret;
 183 }
 184
 185 static int check_sender_args(int argc, char * const * argv, struct sender_command_data *scd)
 186 {
 187         int i;
 188         /* this has to match sender.h */
 189         const char *subcmds[] = {"add", "delete", "allow", "deny", "on", "off", NULL};
 190
 191         scd->sender_num = -1;
 192         if (argc < 2)
 193                 return -E_COMMAND_SYNTAX;
 194         for (i = 0; senders[i].name; i++)
 195                 if (!strcmp(senders[i].name, argv[1]))
 196                         break;
 197         PARA_DEBUG_LOG("%d:%s\n", argc, argv[1]);
 198         if (!senders[i].name)
 199                 return -E_COMMAND_SYNTAX;
 200         scd->sender_num = i;
 201         for (i = 0; subcmds[i]; i++)
 202                 if (!strcmp(subcmds[i], argv[2]))
 203                         break;
 204         if (!subcmds[i])
 205                 return -E_COMMAND_SYNTAX;
 206         scd->cmd_num = i;
 207         mmd_lock();
 208         if (!senders[scd->sender_num].client_cmds[scd->cmd_num]) {
 209                 mmd_unlock();
 210                 return -E_SENDER_CMD;
 211         }
 212         mmd_unlock();
 213         switch (scd->cmd_num) {
 214         case SENDER_ON:
 215         case SENDER_OFF:
 216                 if (argc != 3)
 217                         return -E_COMMAND_SYNTAX;
 218                 break;
 219         case SENDER_DENY:
 220         case SENDER_ALLOW:
 221                 if (argc != 4 && argc != 5)
 222                         return -E_COMMAND_SYNTAX;
 223                 if (!inet_pton(AF_INET, argv[3], &scd->addr))
 224                         return -E_COMMAND_SYNTAX;
 225                 scd->netmask = 32;
 226                 if (argc == 5) {
 227                         scd->netmask = atoi(argv[4]);
 228                         if (scd->netmask < 0 || scd->netmask > 32)
 229                                 return -E_COMMAND_SYNTAX;
 230                 }
 231                 break;
 232         case SENDER_ADD:
 233         case SENDER_DELETE:
 234                 if (argc != 4 && argc != 5)
 235                         return -E_COMMAND_SYNTAX;
 236                 if (!inet_pton(AF_INET, argv[3], &scd->addr))
 237                         return -E_COMMAND_SYNTAX;
 238                 scd->port = -1;
 239                 if (argc == 5) {
 240                         scd->port = atoi(argv[4]);
 241                         if (scd->port < 0 || scd->port > 65535)
 242                                 return -E_COMMAND_SYNTAX;
 243                 }
 244                 break;
 245         default:
 246                 return -E_COMMAND_SYNTAX;
 247         }
 248         return 1;
 249 }
 250
 251 int com_sender(int fd, int argc, char * const * argv)
 252 {
 253         int i, ret;
 254         struct sender_command_data scd;
 255
 256         if (argc < 2) {
 257                 char *msg = NULL;
 258                 for (i = 0; senders[i].name; i++) {
 259                         char *tmp = make_message("%s%s\n",
 260                                 msg? msg : "", senders[i].name);
 261                         free(msg);
 262                         msg = tmp;
 263                 }
 264                 ret = send_buffer(fd, msg);
 265                 free(msg);
 266                 return ret;
 267         }
 268         ret = check_sender_args(argc, argv, &scd);
 269         if (ret < 0) {
 270                 char *msg;
 271                 if (scd.sender_num < 0)
 272                         return ret;
 273                 msg = senders[scd.sender_num].help();
 274                 send_buffer(fd, msg);
 275                 free(msg);
 276                 return 1;
 277         }
 278         for (i = 0; i < 10; i++) {
 279                 mmd_lock();
 280                 if (mmd->sender_cmd_data.cmd_num >= 0) {
 281                         mmd_unlock();
 282                         usleep(100 * 1000);
 283                         continue;
 284                 }
 285                 mmd->sender_cmd_data = scd;
 286                 mmd_unlock();
 287                 break;
 288         }
 289         return (i < 10)? 1 : -E_LOCK;
 290 }
 291
 292 /* server info */
 293 int com_si(int fd, int argc, __a_unused char * const * argv)
 294 {
 295         int i, ret;
 296         char *ut;
 297         char *selector_string = NULL, *sender_info = NULL, *sender_list = NULL;
 298
 299         if (argc != 1)
 300                 return -E_COMMAND_SYNTAX;
 301         mmd_lock();
 302         for (i = 0; selectors[i].name; i++) {
 303                 selector_string = para_strcat(selector_string, selectors[i].name);
 304                 selector_string = para_strcat(selector_string, " ");
 305         }
 306         for (i = 0; senders[i].name; i++) {
 307                 char *info = senders[i].info();
 308                 sender_info = para_strcat(sender_info, info);
 309                 free(info);
 310                 sender_list = para_strcat(sender_list, senders[i].name);
 311                 sender_list = para_strcat(sender_list, " ");
 312         }
 313         ut = uptime_str();
 314         ret = send_va_buffer(fd, "up: %s\nplayed: %u\n"
 315                 "pid: %d\n"
 316                 "connections (active/accepted/total): %u/%u/%u\n"
 317                 "current loglevel: %i\n"
 318                 "supported audio file selectors: %s\n"
 319                 "supported audio formats: %s\n"
 320                 "supported senders: %s\n"
 321                 "%s",
 322                 ut, mmd->num_played,
 323                 getppid(),
 324                 mmd->active_connections,
 325                 mmd->num_commands,
 326                 mmd->num_connects,
 327                 conf.loglevel_arg,
 328                 selector_string,
 329                 supported_audio_formats(),
 330                 sender_list,
 331                 sender_info
 332         );
 333         mmd_unlock();
 334         free(ut);
 335         free(selector_string);
 336         free(sender_list);
 337         free(sender_info);
 338         return ret;
 339 }
 340
 341 /* version */
 342 int com_version(int fd, int argc, __a_unused char * const * argv)
 343 {
 344         if (argc != 1)
 345                 return -E_COMMAND_SYNTAX;
 346         return send_buffer(fd, VERSION_TEXT("server")
 347                 "built: " BUILD_DATE "\n"
 348                 SYSTEM ", " CC_VERSION "\n"
 349         );
 350 }
 351
 352 /* sc */
 353 int com_sc(int fd, int argc, char * const * argv)
 354 {
 355         char *name = NULL;
 356         int ret, old = 0, count = -1; /* print af change forever */
 357
 358         if (argc > 1)
 359                 count = atoi(argv[1]);
 360 repeat:
 361         mmd_lock();
 362         if (old != mmd->num_played) {
 363                 old = mmd->num_played;
 364                 name = para_strdup(mmd->filename);
 365         }
 366         mmd_unlock();
 367         if (name) {
 368                 ret = send_va_buffer(fd, "%s\n", name);
 369                 free(name);
 370                 name = NULL;
 371                 if (ret < 0)
 372                         return ret;
 373                 if (argc > 1 && !--count)
 374                         return 1;
 375         }
 376         usleep(500000);
 377         goto repeat;
 378 }
 379
 380 /* sb */
 381 int com_sb(int fd, int argc, char * const * argv)
 382 {
 383         char *sb;
 384         int ret, nr = -1;       /* status bar will be printed that many
 385                                  * times. Negative value means: print
 386                                  * forever
 387                                  */
 388         if (argc > 1)
 389                 nr = atoi(argv[1]);
 390         while (nr) {
 391                 mmd_lock();
 392                 sb = get_sb_string(mmd);
 393                 mmd_unlock();
 394                 ret = send_va_buffer(fd, "%s\n", sb);
 395                 free(sb);
 396                 if (ret < 0)
 397                         return ret;
 398                 if (nr == 1)
 399                         return 1;
 400                 usleep(500000);
 401                 if (nr > 0)
 402                         nr--;
 403         }
 404         return 1;
 405 }
 406
 407 /* stat */
 408 int com_stat(int fd, int argc, char * const * argv)
 409 {
 410         int ret, num = 0;/* status will be printed that many
 411                           * times. num <= 0 means: print forever
 412                           */
 413         struct misc_meta_data tmp, *nmmd = &tmp;
 414         char *s;
 415
 416         signal(SIGUSR1, dummy);
 417
 418         if (argc > 1)
 419                 num = atoi(argv[1]);
 420         for (;;) {
 421
 422                 mmd_dup(nmmd);
 423                 s = get_status(nmmd);
 424                 ret = send_buffer(fd, s);
 425                 free(s);
 426                 if (ret < 0)
 427                         goto out;
 428                 ret = 1;
 429                 if (num == 1)
 430                         goto out;
 431                 sleep(50);
 432                 if (getppid() == 1)
 433                         return -E_SERVER_CRASH;
 434         }
 435 out:
 436         return ret;
 437 }
 438
 439 static int send_list_of_commands(int fd, struct server_command *cmd,
 440                 const char *handler)
 441 {
 442         int ret, i;
 443
 444         for (i = 1; cmd->name; cmd++, i++) {
 445                 char *perms = cmd_perms_itohuman(cmd->perms);
 446                 ret = send_va_buffer(fd, "%s\t%s\t%s\t%s\n", cmd->name,
 447                         handler,
 448                         perms,
 449                         cmd->description);
 450                 free(perms);
 451                 if (ret < 0)
 452                         return ret;
 453         }
 454         return 1;
 455 }
 456
 457 /* always returns string that must be freed by the caller in handler */
 458 static struct server_command *get_cmd_ptr(const char *name, char **handler)
 459 {
 460         struct server_command *cmd;
 461
 462         for (cmd = server_cmds; cmd->name; cmd++)
 463                 if (!strcmp(cmd->name, name)) {
 464                         if (handler)
 465                                 *handler = para_strdup("para_server"); /* server commands */
 466                         return cmd;
 467                 }
 468         /* not found, look for commands supported by the current selector */
 469         mmd_lock();
 470         if (handler)
 471                 *handler = make_message("the %s selector",
 472                         selectors[mmd->selector_num].name);
 473         cmd = selectors[mmd->selector_num].cmd_list;
 474         mmd_unlock();
 475         for (; cmd->name; cmd++)
 476                 if (!strcmp(cmd->name, name))
 477                         return cmd;
 478         /* not found, look for commands supported by afs */
 479         for (cmd = afs_cmds; cmd->name; cmd++)
 480                 if (!strcmp(cmd->name, name))
 481                         return cmd;
 482         return NULL;
 483 }
 484
 485 /* help */
 486 int com_help(int fd, int argc, char * const * argv)
 487 {
 488         struct server_command *cmd;
 489         char *perms, *handler;
 490         int ret;
 491
 492         if (argc < 2) {
 493                 /* no argument given, print list of commands */
 494                 if ((ret = send_list_of_commands(fd, server_cmds, "server")) < 0)
 495                         return ret;
 496                 mmd_lock();
 497                 handler = para_strdup(selectors[mmd->selector_num].name);
 498                 cmd = selectors[mmd->selector_num].cmd_list;
 499                 mmd_unlock();
 500                 ret = send_list_of_commands(fd, cmd, handler);
 501                 free(handler);
 502                 if (ret < 0)
 503                         return ret;
 504                 cmd = afs_cmds;
 505                 return send_list_of_commands(fd, cmd, "afs");
 506         }
 507         /* argument given for help */
 508         cmd = get_cmd_ptr(argv[1], &handler);
 509         if (!cmd) {
 510                 free(handler);
 511                 return -E_BAD_CMD;
 512         }
 513         perms = cmd_perms_itohuman(cmd->perms);
 514         ret = send_va_buffer(fd,
 515                 "%s - %s\n\n"
 516                 "handler: %s\n"
 517                 "permissions: %s\n"
 518                 "usage: %s\n\n"
 519                 "%s\n",
 520                 argv[1],
 521                 cmd->description,
 522                 handler,
 523                 perms,
 524                 cmd->usage,
 525                 cmd->help
 526         );
 527         free(perms);
 528         free(handler);
 529         return ret;
 530 }
 531
 532 /* hup */
 533 int com_hup(__a_unused int fd, int argc, __a_unused char * const * argv)
 534 {
 535         if (argc != 1)
 536                 return -E_COMMAND_SYNTAX;
 537         kill(getppid(), SIGHUP);
 538         return 1;
 539 }
 540
 541 /* term */
 542 int com_term(__a_unused int fd, int argc, __a_unused char * const * argv)
 543 {
 544         if (argc != 1)
 545                 return -E_COMMAND_SYNTAX;
 546         kill(getppid(), SIGTERM);
 547         return 1;
 548 }
 549
 550 int com_play(__a_unused int fd, int argc, __a_unused char * const * argv)
 551 {
 552         if (argc != 1)
 553                 return -E_COMMAND_SYNTAX;
 554         mmd_lock();
 555         mmd->new_vss_status_flags |= VSS_PLAYING;
 556         mmd->new_vss_status_flags &= ~VSS_NOMORE;
 557         mmd_unlock();
 558         return 1;
 559
 560 }
 561
 562 /* stop */
 563 int com_stop(__a_unused int fd, int argc, __a_unused char * const * argv)
 564 {
 565         if (argc != 1)
 566                 return -E_COMMAND_SYNTAX;
 567         mmd_lock();
 568         mmd->new_vss_status_flags &= ~VSS_PLAYING;
 569         mmd->new_vss_status_flags &= ~VSS_REPOS;
 570         mmd->new_vss_status_flags |= VSS_NEXT;
 571         mmd_unlock();
 572         return 1;
 573 }
 574
 575 /* pause */
 576 int com_pause(__a_unused int fd, int argc, __a_unused char * const * argv)
 577 {
 578         if (argc != 1)
 579                 return -E_COMMAND_SYNTAX;
 580         mmd_lock();
 581         if (!vss_paused())
 582                 mmd->events++;
 583         mmd->new_vss_status_flags &= ~VSS_PLAYING;
 584         mmd->new_vss_status_flags &= ~VSS_NEXT;
 585         mmd_unlock();
 586         return 1;
 587 }
 588
 589 int com_chs(int fd, int argc, char * const * argv)
 590 {
 591         int i, ret;
 592
 593         if (argc == 1) {
 594                 char *selector;
 595                 mmd_lock();
 596                 selector = para_strdup(selectors[mmd->selector_num].name);
 597                 mmd_unlock();
 598                 ret = send_va_buffer(fd, "%s\n", selector);
 599                 free(selector);
 600                 return ret;
 601         }
 602         for (i = 0; selectors[i].name; i++) {
 603                 if (strcmp(selectors[i].name, argv[1]))
 604                         continue;
 605                 mmd_lock();
 606                 mmd->selector_change = i;
 607                 mmd->events++;
 608                 mmd_unlock();
 609                 return 1;
 610         }
 611         return -E_BAD_SELECTOR;
 612 }
 613
 614 /* next */
 615 int com_next(__a_unused int fd, int argc, __a_unused char * const * argv)
 616 {
 617         if (argc != 1)
 618                 return -E_COMMAND_SYNTAX;
 619         mmd_lock();
 620         mmd->events++;
 621         mmd->new_vss_status_flags |= VSS_NEXT;
 622         mmd_unlock();
 623         return 1;
 624 }
 625
 626 /* nomore */
 627 int com_nomore(__a_unused int fd, int argc, __a_unused char * const * argv)
 628 {
 629         if (argc != 1)
 630                 return -E_COMMAND_SYNTAX;
 631         mmd_lock();
 632         if (vss_playing() || vss_paused())
 633                 mmd->new_vss_status_flags |= VSS_NOMORE;
 634         mmd_unlock();
 635         return 1;
 636 }
 637
 638 /* ff */
 639 int com_ff(__a_unused int fd, int argc, char * const * argv)
 640 {
 641         long promille;
 642         int ret, backwards = 0;
 643         unsigned i;
 644         char c;
 645
 646         if (argc != 2)
 647                 return -E_COMMAND_SYNTAX;
 648         if (!(ret = sscanf(argv[1], "%u%c", &i, &c)))
 649                 return -E_COMMAND_SYNTAX;
 650         if (ret > 1 && c == '-')
 651                 backwards = 1; /* jmp backwards */
 652         mmd_lock();
 653         ret = -E_NO_AUDIO_FILE;
 654         if (!mmd->afi.chunks_total || !mmd->afi.seconds_total)
 655                 goto out;
 656         promille = (1000 * mmd->current_chunk) / mmd->afi.chunks_total;
 657         if (backwards)
 658                 promille -= 1000 * i / mmd->afi.seconds_total;
 659         else
 660                 promille += 1000 * i / mmd->afi.seconds_total;
 661         if (promille < 0)
 662                 promille = 0;
 663         if (promille >  1000) {
 664                 mmd->new_vss_status_flags |= VSS_NEXT;
 665                 goto out;
 666         }
 667         mmd->repos_request = (mmd->afi.chunks_total * promille) / 1000;
 668         mmd->new_vss_status_flags |= VSS_REPOS;
 669         mmd->new_vss_status_flags &= ~VSS_NEXT;
 670         mmd->events++;
 671         ret = 1;
 672 out:
 673         mmd_unlock();
 674         return ret;
 675 }
 676
 677 /* jmp */
 678 int com_jmp(__a_unused int fd, int argc, char * const * argv)
 679 {
 680         long unsigned int i;
 681         int ret;
 682
 683         if (argc != 2)
 684                 return -E_COMMAND_SYNTAX;
 685         if (sscanf(argv[1], "%lu", &i) <= 0)
 686                 return -E_COMMAND_SYNTAX;
 687         mmd_lock();
 688         ret = -E_NO_AUDIO_FILE;
 689         if (!mmd->afi.chunks_total)
 690                 goto out;
 691         if (i > 100)
 692                 i = 100;
 693         PARA_INFO_LOG("jumping to %lu%%\n", i);
 694         mmd->repos_request = (mmd->afi.chunks_total * i + 50)/ 100;
 695         PARA_INFO_LOG("sent: %lu,  offset before jmp: %lu\n",
 696                 mmd->chunks_sent, mmd->offset);
 697         mmd->new_vss_status_flags |= VSS_REPOS;
 698         mmd->new_vss_status_flags &= ~VSS_NEXT;
 699         ret = 1;
 700         mmd->events++;
 701 out:
 702         mmd_unlock();
 703         return ret;
 704 }
 705
 706 /*
 707  * check if perms are sufficient to exec a command having perms cmd_perms.
 708  * Returns 0 if perms are sufficient, -E_PERM otherwise.
 709  */
 710 static int check_perms(unsigned int perms, struct server_command *cmd_ptr)
 711 {
 712         PARA_DEBUG_LOG("%s", "checking permissions\n");
 713         return (cmd_ptr->perms & perms) < cmd_ptr->perms ? -E_PERM : 0;
 714 }
 715
 716 /*
 717  * Parse first string from *cmd and lookup in table of valid commands.
 718  * On error, NULL is returned.
 719  */
 720 static struct server_command *parse_cmd(const char *cmdstr)
 721 {
 722         char buf[255];
 723         int n = 0;
 724
 725         sscanf(cmdstr, "%200s%n", buf, &n);
 726         if (!n)
 727                 return NULL;
 728         buf[n] = '\0';
 729         return get_cmd_ptr(buf, NULL);
 730 }
 731
 732 static long int para_rand(long unsigned max)
 733 {
 734         return (long int) ((max + 0.0) * (random() / (RAND_MAX + 1.0)));
 735 }
 736
 737 static void init_rc4_keys(void)
 738 {
 739         int i;
 740
 741         for (i = 0; i < 2 * RC4_KEY_LEN; i++)
 742                 rc4_buf[i] = para_rand(256);
 743         PARA_DEBUG_LOG("rc4 keys initialized (%u:%u)\n",
 744                 (unsigned char) rc4_buf[0],
 745                 (unsigned char) rc4_buf[RC4_KEY_LEN]);
 746         RC4_set_key(&rc4_recv_key, RC4_KEY_LEN, rc4_buf);
 747         RC4_set_key(&rc4_send_key, RC4_KEY_LEN, rc4_buf + RC4_KEY_LEN);
 748 }
 749
 750 static void rc4_recv(unsigned long len, const unsigned char *indata,
 751                 unsigned char *outdata, __a_unused void *private_data)
 752 {
 753         RC4(&rc4_recv_key, len, indata, outdata);
 754 }
 755
 756 static void rc4_send(unsigned long len, const unsigned char *indata,
 757                 unsigned char *outdata, __a_unused void *private_data)
 758 {
 759         RC4(&rc4_send_key, len, indata, outdata);
 760 }
 761
 762 static int read_command(int fd, char **result)
 763 {
 764         int ret;
 765         char buf[4096];
 766         char *command = NULL;
 767
 768         for (;;) {
 769                 size_t numbytes;
 770                 char *p;
 771
 772                 ret = recv_buffer(fd, buf, sizeof(buf));
 773                 if (ret < 0)
 774                         goto out;
 775                 if (!ret)
 776                         break;
 777                 numbytes = ret;
 778                 ret = -E_COMMAND_SYNTAX;
 779                 if (command && numbytes + strlen(command) > MAX_COMMAND_LEN) /* DOS */
 780                         goto out;
 781                 command = para_strcat(command, buf);
 782                 p = strstr(command, EOC_MSG);
 783                 if (p) {
 784                         *p = '\0';
 785                         break;
 786                 }
 787         }
 788         ret = command? 1 : -E_COMMAND_SYNTAX;
 789 out:
 790         if (ret < 0)
 791                 free(command);
 792         else
 793                 *result = command;
 794         return ret;
 795
 796 }
 797
 798 /**
 799  * perform user authentication and execute a command
 800  *
 801  * \param fd the file descriptor to send output to
 802  * \param addr socket address info of peer
 803  *
 804  * \return EXIT_SUCCESS or EXIT_FAILURE
 805  *
 806  * Whenever para_server accepts an incoming tcp connection on
 807  * the port it listens on, it forks and the resulting child
 808  * calls this function.
 809  *
 810  * An RSA-based challenge/response is used to authenticate
 811  * the peer. It that authentication succeeds, a random RC4
 812  * session key is generated and sent back to the peer,
 813  * encrypted with its RSA public key.  From this point on,
 814  * all transfers are crypted with this session key.
 815  *
 816  * Next it is checked if the peer supplied  a valid server
 817  * command or a command for the audio file selector currently
 818  * in use.  If yes, and if the user has sufficient
 819  * permissions to execute that command, the function calls
 820  * the corresponding command handler which does argument
 821  * checking and further processing.
 822  *
 823  * In order to cope with a DOS attacks, a timeout is set up
 824  * which terminates the function if the connection was not
 825  * authenticated when the timeout expires.
 826  *
 827  * \sa alarm(2), rc4(3), crypt.c, crypt.h
 828  */
 829 int handle_connect(int fd, struct sockaddr_in *addr)
 830 {
 831         int ret, argc, use_rc4 = 0;
 832         char buf[4096];
 833         unsigned char crypt_buf[MAXLINE];
 834         struct user *u;
 835         struct server_command *cmd = NULL;
 836         long unsigned challenge_nr, chall_response;
 837         char **argv = NULL;
 838         char *p, *command = NULL;
 839         size_t numbytes;
 840
 841         signal(SIGCHLD, SIG_IGN);
 842         signal(SIGINT, SIG_DFL);
 843         signal(SIGTERM, SIG_DFL);
 844         signal(SIGHUP, SIG_DFL);
 845         signal(SIGUSR1, SIG_IGN);
 846
 847         challenge_nr = random();
 848         /* send Welcome message */
 849         ret = send_va_buffer(fd, "This is para_server, version "
 850                 PACKAGE_VERSION  ".\n" );
 851         if (ret < 0)
 852                 goto err_out;
 853         /* recv auth request line */
 854         ret = recv_buffer(fd, buf, sizeof(buf));
 855         if (ret < 0)
 856                 goto err_out;
 857         if (ret <= 6) {
 858                 ret = -E_AUTH;
 859                 goto err_out;
 860         }
 861         numbytes = ret;
 862         ret = -E_AUTH;
 863         if (strncmp(buf, "auth ", 5))
 864                 goto err_out;
 865
 866         if (numbytes < 9 || strncmp(buf, "auth rc4 ", 9))
 867                 p = buf + 5; /* client version < 0.2.6 */
 868         else {
 869                 p = buf + 9; /* client version >= 0.2.6 */
 870                 use_rc4 = 1;
 871         }
 872         PARA_DEBUG_LOG("received %s request for user %s\n",
 873                 use_rc4? "rc4" : "auth", p);
 874         ret = -E_BAD_USER;
 875         u = lookup_user(p);
 876         if (!u)
 877                 goto err_out;
 878         ret = para_encrypt_challenge(u->rsa, challenge_nr, crypt_buf);
 879         if (ret <= 0)
 880                 goto err_out;
 881         numbytes = ret;
 882         PARA_DEBUG_LOG("sending %zu byte challenge\n", numbytes);
 883         /* We can't use send_buffer here since buf may contain null bytes */
 884         ret = send_bin_buffer(fd,(char *) crypt_buf, numbytes);
 885         if (ret < 0)
 886                 goto err_out;
 887         /* recv decrypted number */
 888         ret = recv_buffer(fd, buf, sizeof(buf));
 889         if (ret < 0)
 890                 goto err_out;
 891         numbytes = ret;
 892         ret = -E_AUTH;
 893         if (!numbytes)
 894                 goto err_out;
 895         if (sscanf(buf, CHALLENGE_RESPONSE_MSG "%lu", &chall_response) < 1
 896                         || chall_response != challenge_nr)
 897                 goto err_out;
 898         /* auth successful, send 'Proceed' message */
 899         PARA_INFO_LOG("good auth for %s (%lu)\n", u->name, challenge_nr);
 900         sprintf(buf, "%s", PROCEED_MSG);
 901         if (use_rc4) {
 902                 init_rc4_keys();
 903                 ret = para_encrypt_buffer(u->rsa, rc4_buf, 2 * RC4_KEY_LEN,
 904                         (unsigned char *)buf + PROCEED_MSG_LEN + 1);
 905                 if (ret <= 0)
 906                         goto err_out;
 907                 numbytes = ret + strlen(PROCEED_MSG) + 1;
 908         } else
 909                 numbytes = strlen(buf);
 910         ret = send_bin_buffer(fd, buf, numbytes);
 911         if (ret < 0)
 912                 goto err_out;
 913         if (use_rc4)
 914                 enable_crypt(fd, rc4_recv, rc4_send, NULL);
 915         ret = read_command(fd, &command);
 916         if (ret < 0)
 917                 goto err_out;
 918         ret = -E_BAD_CMD;
 919         cmd = parse_cmd(command);
 920         if (!cmd)
 921                 goto err_out;
 922         /* valid command, check permissions */
 923         ret = check_perms(u->perms, cmd);
 924         if (ret < 0)
 925                 goto err_out;
 926         /* valid command and sufficient perms */
 927         alarm(0);
 928         argc = split_args(command, &argv, "\n");
 929         mmd_lock();
 930         mmd->num_commands++;
 931         mmd_unlock();
 932         PARA_NOTICE_LOG("calling com_%s() for %s@%s\n", cmd->name, u->name,
 933                 inet_ntoa(addr->sin_addr));
 934         ret = cmd->handler(fd, argc, argv);
 935         if (ret >= 0) {
 936                 ret = EXIT_SUCCESS;
 937                 goto out;
 938         }
 939 err_out:
 940         PARA_NOTICE_LOG("%s\n", PARA_STRERROR(-ret));
 941         if (ret != -E_SEND && ret != -E_RECV)
 942                 send_va_buffer(fd, "%s\n", PARA_STRERROR(-ret));
 943         ret = EXIT_FAILURE;
 944 out:
 945         free(command);
 946         free(argv);
 947         mmd_lock();
 948         if (cmd && (cmd->perms & AFS_WRITE) && ret >= 0)
 949                 mmd->events++;
 950         mmd->active_connections--;
 951         mmd_unlock();
 952         return ret;
 953 }