release/src/router/dnsmasq/src/helper.c

   1 /* dnsmasq is Copyright (c) 2000-2015 Simon Kelley
   2
   3    This program is free software; you can redistribute it and/or modify
   4    it under the terms of the GNU General Public License as published by
   5    the Free Software Foundation; version 2 dated June, 1991, or
   6    (at your option) version 3 dated 29 June, 2007.
   7
   8    This program is distributed in the hope that it will be useful,
   9    but WITHOUT ANY WARRANTY; without even the implied warranty of
  10    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11    GNU General Public License for more details.
  12
  13    You should have received a copy of the GNU General Public License
  14    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  15 */
  16
  17 #include "dnsmasq.h"
  18
  19 #ifdef HAVE_SCRIPT
  20
  21 /* This file has code to fork a helper process which recieves data via a pipe
  22    shared with the main process and which is responsible for calling a script when
  23    DHCP leases change.
  24
  25    The helper process is forked before the main process drops root, so it retains root
  26    privs to pass on to the script. For this reason it tries to be paranoid about
  27    data received from the main process, in case that has been compromised. We don't
  28    want the helper to give an attacker root. In particular, the script to be run is
  29    not settable via the pipe, once the fork has taken place it is not alterable by the
  30    main process.
  31 */
  32
  33 static void my_setenv(const char *name, const char *value, int *error);
  34 static unsigned char *grab_extradata(unsigned char *buf, unsigned char *end,  char *env, int *err);
  35
  36 #ifdef HAVE_LUASCRIPT
  37 #define LUA_COMPAT_ALL
  38 #include <lua.h>
  39 #include <lualib.h>
  40 #include <lauxlib.h>
  41
  42 #ifndef lua_open
  43 #define lua_open()     luaL_newstate()
  44 #endif
  45
  46 lua_State *lua;
  47
  48 static unsigned char *grab_extradata_lua(unsigned char *buf, unsigned char *end, char *field);
  49 #endif
  50
  51
  52 struct script_data
  53 {
  54   int flags;
  55   int action, hwaddr_len, hwaddr_type;
  56   int clid_len, hostname_len, ed_len;
  57   struct in_addr addr, giaddr;
  58   unsigned int remaining_time;
  59 #ifdef HAVE_BROKEN_RTC
  60   unsigned int length;
  61 #else
  62   time_t expires;
  63 #endif
  64 #ifdef HAVE_TFTP
  65   off_t file_len;
  66 #endif
  67 #ifdef HAVE_IPV6
  68   struct in6_addr addr6;
  69 #endif
  70 #ifdef HAVE_DHCP6
  71   int iaid, vendorclass_count;
  72 #endif
  73   unsigned char hwaddr[DHCP_CHADDR_MAX];
  74   char interface[IF_NAMESIZE];
  75 };
  76
  77 static struct script_data *buf = NULL;
  78 static size_t bytes_in_buf = 0, buf_size = 0;
  79
  80 int create_helper(int event_fd, int err_fd, uid_t uid, gid_t gid, long max_fd)
  81 {
  82   pid_t pid;
  83   int i, pipefd[2];
  84   struct sigaction sigact;
  85
  86   /* create the pipe through which the main program sends us commands,
  87      then fork our process. */
  88   if (pipe(pipefd) == -1 || !fix_fd(pipefd[1]) || (pid = fork()) == -1)
  89     {
  90       send_event(err_fd, EVENT_PIPE_ERR, errno, NULL);
  91       _exit(0);
  92     }
  93
  94   if (pid != 0)
  95     {
  96       close(pipefd[0]); /* close reader side */
  97       return pipefd[1];
  98     }
  99
 100   /* ignore SIGTERM, so that we can clean up when the main process gets hit
 101      and SIGALRM so that we can use sleep() */
 102   sigact.sa_handler = SIG_IGN;
 103   sigact.sa_flags = 0;
 104   sigemptyset(&sigact.sa_mask);
 105   sigaction(SIGTERM, &sigact, NULL);
 106   sigaction(SIGALRM, &sigact, NULL);
 107
 108   if (!option_bool(OPT_DEBUG) && uid != 0)
 109     {
 110       gid_t dummy;
 111       if (setgroups(0, &dummy) == -1 ||
 112           setgid(gid) == -1 ||
 113           setuid(uid) == -1)
 114         {
 115           if (option_bool(OPT_NO_FORK))
 116             /* send error to daemon process if no-fork */
 117             send_event(event_fd, EVENT_USER_ERR, errno, daemon->scriptuser);
 118           else
 119             {
 120               /* kill daemon */
 121               send_event(event_fd, EVENT_DIE, 0, NULL);
 122               /* return error */
 123               send_event(err_fd, EVENT_USER_ERR, errno, daemon->scriptuser);
 124             }
 125           _exit(0);
 126         }
 127     }
 128
 129   /* close all the sockets etc, we don't need them here.
 130      Don't close err_fd, in case the lua-init fails.
 131      Note that we have to do this before lua init
 132      so we don't close any lua fds. */
 133   for (max_fd--; max_fd >= 0; max_fd--)
 134     if (max_fd != STDOUT_FILENO && max_fd != STDERR_FILENO &&
 135         max_fd != STDIN_FILENO && max_fd != pipefd[0] &&
 136         max_fd != event_fd && max_fd != err_fd)
 137       close(max_fd);
 138
 139 #ifdef HAVE_LUASCRIPT
 140   if (daemon->luascript)
 141     {
 142       const char *lua_err = NULL;
 143       lua = lua_open();
 144       luaL_openlibs(lua);
 145
 146       /* get Lua to load our script file */
 147       if (luaL_dofile(lua, daemon->luascript) != 0)
 148         lua_err = lua_tostring(lua, -1);
 149       else
 150         {
 151           lua_getglobal(lua, "lease");
 152           if (lua_type(lua, -1) != LUA_TFUNCTION)
 153             lua_err = _("lease() function missing in Lua script");
 154         }
 155
 156       if (lua_err)
 157         {
 158           if (option_bool(OPT_NO_FORK) || option_bool(OPT_DEBUG))
 159             /* send error to daemon process if no-fork */
 160             send_event(event_fd, EVENT_LUA_ERR, 0, (char *)lua_err);
 161           else
 162             {
 163               /* kill daemon */
 164               send_event(event_fd, EVENT_DIE, 0, NULL);
 165               /* return error */
 166               send_event(err_fd, EVENT_LUA_ERR, 0, (char *)lua_err);
 167             }
 168           _exit(0);
 169         }
 170
 171       lua_pop(lua, 1);  /* remove nil from stack */
 172       lua_getglobal(lua, "init");
 173       if (lua_type(lua, -1) == LUA_TFUNCTION)
 174         lua_call(lua, 0, 0);
 175       else
 176         lua_pop(lua, 1);  /* remove nil from stack */
 177     }
 178 #endif
 179
 180   /* All init done, close our copy of the error pipe, so that main process can return */
 181   if (err_fd != -1)
 182     close(err_fd);
 183
 184   /* loop here */
 185   while(1)
 186     {
 187       struct script_data data;
 188       char *p, *action_str, *hostname = NULL, *domain = NULL;
 189       unsigned char *buf = (unsigned char *)daemon->namebuff;
 190       unsigned char *end, *extradata, *alloc_buff = NULL;
 191       int is6, err = 0;
 192
 193       free(alloc_buff);
 194
 195       /* we read zero bytes when pipe closed: this is our signal to exit */
 196       if (!read_write(pipefd[0], (unsigned char *)&data, sizeof(data), 1))
 197         {
 198 #ifdef HAVE_LUASCRIPT
 199           if (daemon->luascript)
 200             {
 201               lua_getglobal(lua, "shutdown");
 202               if (lua_type(lua, -1) == LUA_TFUNCTION)
 203                 lua_call(lua, 0, 0);
 204             }
 205 #endif
 206           _exit(0);
 207         }
 208
 209       is6 = !!(data.flags & (LEASE_TA | LEASE_NA));
 210
 211       if (data.action == ACTION_DEL)
 212         action_str = "del";
 213       else if (data.action == ACTION_ADD)
 214         action_str = "add";
 215       else if (data.action == ACTION_OLD || data.action == ACTION_OLD_HOSTNAME)
 216         action_str = "old";
 217       else if (data.action == ACTION_TFTP)
 218         {
 219           action_str = "tftp";
 220           is6 = (data.flags != AF_INET);
 221         }
 222       else
 223         continue;
 224
 225
 226       /* stringify MAC into dhcp_buff */
 227       p = daemon->dhcp_buff;
 228       if (data.hwaddr_type != ARPHRD_ETHER || data.hwaddr_len == 0)
 229         p += sprintf(p, "%.2x-", data.hwaddr_type);
 230       for (i = 0; (i < data.hwaddr_len) && (i < DHCP_CHADDR_MAX); i++)
 231         {
 232           p += sprintf(p, "%.2x", data.hwaddr[i]);
 233           if (i != data.hwaddr_len - 1)
 234             p += sprintf(p, ":");
 235         }
 236
 237       /* supplied data may just exceed normal buffer (unlikely) */
 238       if ((data.hostname_len + data.ed_len + data.clid_len) > MAXDNAME &&
 239           !(alloc_buff = buf = malloc(data.hostname_len + data.ed_len + data.clid_len)))
 240         continue;
 241
 242       if (!read_write(pipefd[0], buf,
 243                       data.hostname_len + data.ed_len + data.clid_len, 1))
 244         continue;
 245
 246       /* CLID into packet */
 247       for (p = daemon->packet, i = 0; i < data.clid_len; i++)
 248         {
 249           p += sprintf(p, "%.2x", buf[i]);
 250           if (i != data.clid_len - 1)
 251               p += sprintf(p, ":");
 252         }
 253
 254 #ifdef HAVE_DHCP6
 255       if (is6)
 256         {
 257           /* or IAID and server DUID for IPv6 */
 258           sprintf(daemon->dhcp_buff3, "%s%u", data.flags & LEASE_TA ? "T" : "", data.iaid);
 259           for (p = daemon->dhcp_packet.iov_base, i = 0; i < daemon->duid_len; i++)
 260             {
 261               p += sprintf(p, "%.2x", daemon->duid[i]);
 262               if (i != daemon->duid_len - 1)
 263                 p += sprintf(p, ":");
 264             }
 265
 266         }
 267 #endif
 268
 269       buf += data.clid_len;
 270
 271       if (data.hostname_len != 0)
 272         {
 273           char *dot;
 274           hostname = (char *)buf;
 275           hostname[data.hostname_len - 1] = 0;
 276           if (data.action != ACTION_TFTP)
 277             {
 278               if (!legal_hostname(hostname))
 279                 hostname = NULL;
 280               else if ((dot = strchr(hostname, '.')))
 281                 {
 282                   domain = dot+1;
 283                   *dot = 0;
 284                 }
 285             }
 286         }
 287
 288       extradata = buf + data.hostname_len;
 289
 290       if (!is6)
 291         inet_ntop(AF_INET, &data.addr, daemon->addrbuff, ADDRSTRLEN);
 292 #ifdef HAVE_DHCP6
 293       else
 294         inet_ntop(AF_INET6, &data.addr6, daemon->addrbuff, ADDRSTRLEN);
 295 #endif
 296
 297 #ifdef HAVE_TFTP
 298       /* file length */
 299       if (data.action == ACTION_TFTP)
 300         sprintf(is6 ? daemon->packet : daemon->dhcp_buff, "%lu", (unsigned long)data.file_len);
 301 #endif
 302
 303 #ifdef HAVE_LUASCRIPT
 304       if (daemon->luascript)
 305         {
 306           if (data.action == ACTION_TFTP)
 307             {
 308               lua_getglobal(lua, "tftp");
 309               if (lua_type(lua, -1) != LUA_TFUNCTION)
 310                 lua_pop(lua, 1); /* tftp function optional */
 311               else
 312                 {
 313                   lua_pushstring(lua, action_str); /* arg1 - action */
 314                   lua_newtable(lua);               /* arg2 - data table */
 315                   lua_pushstring(lua, daemon->addrbuff);
 316                   lua_setfield(lua, -2, "destination_address");
 317                   lua_pushstring(lua, hostname);
 318                   lua_setfield(lua, -2, "file_name");
 319                   lua_pushstring(lua, is6 ? daemon->packet : daemon->dhcp_buff);
 320                   lua_setfield(lua, -2, "file_size");
 321                   lua_call(lua, 2, 0);  /* pass 2 values, expect 0 */
 322                 }
 323             }
 324           else
 325             {
 326               lua_getglobal(lua, "lease");     /* function to call */
 327               lua_pushstring(lua, action_str); /* arg1 - action */
 328               lua_newtable(lua);               /* arg2 - data table */
 329
 330               if (is6)
 331                 {
 332                   lua_pushstring(lua, daemon->packet);
 333                   lua_setfield(lua, -2, "client_duid");
 334                   lua_pushstring(lua, daemon->dhcp_packet.iov_base);
 335                   lua_setfield(lua, -2, "server_duid");
 336                   lua_pushstring(lua, daemon->dhcp_buff3);
 337                   lua_setfield(lua, -2, "iaid");
 338                 }
 339
 340               if (!is6 && data.clid_len != 0)
 341                 {
 342                   lua_pushstring(lua, daemon->packet);
 343                   lua_setfield(lua, -2, "client_id");
 344                 }
 345
 346               if (strlen(data.interface) != 0)
 347                 {
 348                   lua_pushstring(lua, data.interface);
 349                   lua_setfield(lua, -2, "interface");
 350                 }
 351
 352 #ifdef HAVE_BROKEN_RTC
 353               lua_pushnumber(lua, data.length);
 354               lua_setfield(lua, -2, "lease_length");
 355 #else
 356               lua_pushnumber(lua, data.expires);
 357               lua_setfield(lua, -2, "lease_expires");
 358 #endif
 359
 360               if (hostname)
 361                 {
 362                   lua_pushstring(lua, hostname);
 363                   lua_setfield(lua, -2, "hostname");
 364                 }
 365
 366               if (domain)
 367                 {
 368                   lua_pushstring(lua, domain);
 369                   lua_setfield(lua, -2, "domain");
 370                 }
 371
 372               end = extradata + data.ed_len;
 373               buf = extradata;
 374
 375               if (!is6)
 376                 buf = grab_extradata_lua(buf, end, "vendor_class");
 377 #ifdef HAVE_DHCP6
 378               else  if (data.vendorclass_count != 0)
 379                 {
 380                   sprintf(daemon->dhcp_buff2, "vendor_class_id");
 381                   buf = grab_extradata_lua(buf, end, daemon->dhcp_buff2);
 382                   for (i = 0; i < data.vendorclass_count - 1; i++)
 383                     {
 384                       sprintf(daemon->dhcp_buff2, "vendor_class%i", i);
 385                       buf = grab_extradata_lua(buf, end, daemon->dhcp_buff2);
 386                     }
 387                 }
 388 #endif
 389
 390               buf = grab_extradata_lua(buf, end, "supplied_hostname");
 391
 392               if (!is6)
 393                 {
 394                   buf = grab_extradata_lua(buf, end, "cpewan_oui");
 395                   buf = grab_extradata_lua(buf, end, "cpewan_serial");
 396                   buf = grab_extradata_lua(buf, end, "cpewan_class");
 397                   buf = grab_extradata_lua(buf, end, "circuit_id");
 398                   buf = grab_extradata_lua(buf, end, "subscriber_id");
 399                   buf = grab_extradata_lua(buf, end, "remote_id");
 400                 }
 401
 402               buf = grab_extradata_lua(buf, end, "tags");
 403
 404               if (is6)
 405                 buf = grab_extradata_lua(buf, end, "relay_address");
 406               else if (data.giaddr.s_addr != 0)
 407                 {
 408                   lua_pushstring(lua, inet_ntoa(data.giaddr));
 409                   lua_setfield(lua, -2, "relay_address");
 410                 }
 411
 412               for (i = 0; buf; i++)
 413                 {
 414                   sprintf(daemon->dhcp_buff2, "user_class%i", i);
 415                   buf = grab_extradata_lua(buf, end, daemon->dhcp_buff2);
 416                 }
 417
 418               if (data.action != ACTION_DEL && data.remaining_time != 0)
 419                 {
 420                   lua_pushnumber(lua, data.remaining_time);
 421                   lua_setfield(lua, -2, "time_remaining");
 422                 }
 423
 424               if (data.action == ACTION_OLD_HOSTNAME && hostname)
 425                 {
 426                   lua_pushstring(lua, hostname);
 427                   lua_setfield(lua, -2, "old_hostname");
 428                 }
 429
 430               if (!is6 || data.hwaddr_len != 0)
 431                 {
 432                   lua_pushstring(lua, daemon->dhcp_buff);
 433                   lua_setfield(lua, -2, "mac_address");
 434                 }
 435
 436               lua_pushstring(lua, daemon->addrbuff);
 437               lua_setfield(lua, -2, "ip_address");
 438
 439               lua_call(lua, 2, 0);      /* pass 2 values, expect 0 */
 440             }
 441         }
 442 #endif
 443
 444       /* no script, just lua */
 445       if (!daemon->lease_change_command)
 446         continue;
 447
 448       /* possible fork errors are all temporary resource problems */
 449       while ((pid = fork()) == -1 && (errno == EAGAIN || errno == ENOMEM))
 450         sleep(2);
 451
 452       if (pid == -1)
 453         continue;
 454
 455       /* wait for child to complete */
 456       if (pid != 0)
 457         {
 458           /* reap our children's children, if necessary */
 459           while (1)
 460             {
 461               int status;
 462               pid_t rc = wait(&status);
 463
 464               if (rc == pid)
 465                 {
 466                   /* On error send event back to main process for logging */
 467                   if (WIFSIGNALED(status))
 468                     send_event(event_fd, EVENT_KILLED, WTERMSIG(status), NULL);
 469                   else if (WIFEXITED(status) && WEXITSTATUS(status) != 0)
 470                     send_event(event_fd, EVENT_EXITED, WEXITSTATUS(status), NULL);
 471                   break;
 472                 }
 473
 474               if (rc == -1 && errno != EINTR)
 475                 break;
 476             }
 477
 478           continue;
 479         }
 480
 481       if (data.action != ACTION_TFTP)
 482         {
 483 #ifdef HAVE_DHCP6
 484           my_setenv("DNSMASQ_IAID", is6 ? daemon->dhcp_buff3 : NULL, &err);
 485           my_setenv("DNSMASQ_SERVER_DUID", is6 ? daemon->dhcp_packet.iov_base : NULL, &err);
 486           my_setenv("DNSMASQ_MAC", is6 && data.hwaddr_len != 0 ? daemon->dhcp_buff : NULL, &err);
 487 #endif
 488
 489           my_setenv("DNSMASQ_CLIENT_ID", !is6 && data.clid_len != 0 ? daemon->packet : NULL, &err);
 490           my_setenv("DNSMASQ_INTERFACE", strlen(data.interface) != 0 ? data.interface : NULL, &err);
 491
 492 #ifdef HAVE_BROKEN_RTC
 493           sprintf(daemon->dhcp_buff2, "%u", data.length);
 494           my_setenv("DNSMASQ_LEASE_LENGTH", daemon->dhcp_buff2, &err);
 495 #else
 496           sprintf(daemon->dhcp_buff2, "%lu", (unsigned long)data.expires);
 497           my_setenv("DNSMASQ_LEASE_EXPIRES", daemon->dhcp_buff2, &err);
 498 #endif
 499
 500           my_setenv("DNSMASQ_DOMAIN", domain, &err);
 501
 502           end = extradata + data.ed_len;
 503           buf = extradata;
 504
 505           if (!is6)
 506             buf = grab_extradata(buf, end, "DNSMASQ_VENDOR_CLASS", &err);
 507 #ifdef HAVE_DHCP6
 508           else
 509             {
 510               if (data.vendorclass_count != 0)
 511                 {
 512                   buf = grab_extradata(buf, end, "DNSMASQ_VENDOR_CLASS_ID", &err);
 513                   for (i = 0; i < data.vendorclass_count - 1; i++)
 514                     {
 515                       sprintf(daemon->dhcp_buff2, "DNSMASQ_VENDOR_CLASS%i", i);
 516                       buf = grab_extradata(buf, end, daemon->dhcp_buff2, &err);
 517                     }
 518                 }
 519             }
 520 #endif
 521
 522           buf = grab_extradata(buf, end, "DNSMASQ_SUPPLIED_HOSTNAME", &err);
 523
 524           if (!is6)
 525             {
 526               buf = grab_extradata(buf, end, "DNSMASQ_CPEWAN_OUI", &err);
 527               buf = grab_extradata(buf, end, "DNSMASQ_CPEWAN_SERIAL", &err);
 528               buf = grab_extradata(buf, end, "DNSMASQ_CPEWAN_CLASS", &err);
 529               buf = grab_extradata(buf, end, "DNSMASQ_CIRCUIT_ID", &err);
 530               buf = grab_extradata(buf, end, "DNSMASQ_SUBSCRIBER_ID", &err);
 531               buf = grab_extradata(buf, end, "DNSMASQ_REMOTE_ID", &err);
 532             }
 533
 534           buf = grab_extradata(buf, end, "DNSMASQ_TAGS", &err);
 535
 536           if (is6)
 537             buf = grab_extradata(buf, end, "DNSMASQ_RELAY_ADDRESS", &err);
 538           else
 539             my_setenv("DNSMASQ_RELAY_ADDRESS", data.giaddr.s_addr != 0 ? inet_ntoa(data.giaddr) : NULL, &err);
 540
 541           for (i = 0; buf; i++)
 542             {
 543               sprintf(daemon->dhcp_buff2, "DNSMASQ_USER_CLASS%i", i);
 544               buf = grab_extradata(buf, end, daemon->dhcp_buff2, &err);
 545             }
 546
 547           sprintf(daemon->dhcp_buff2, "%u", data.remaining_time);
 548           my_setenv("DNSMASQ_TIME_REMAINING", data.action != ACTION_DEL && data.remaining_time != 0 ? daemon->dhcp_buff2 : NULL, &err);
 549
 550           my_setenv("DNSMASQ_OLD_HOSTNAME", data.action == ACTION_OLD_HOSTNAME ? hostname : NULL, &err);
 551           if (data.action == ACTION_OLD_HOSTNAME)
 552             hostname = NULL;
 553         }
 554
 555       my_setenv("DNSMASQ_LOG_DHCP", option_bool(OPT_LOG_OPTS) ? "1" : NULL, &err);
 556
 557       /* we need to have the event_fd around if exec fails */
 558       if ((i = fcntl(event_fd, F_GETFD)) != -1)
 559         fcntl(event_fd, F_SETFD, i | FD_CLOEXEC);
 560       close(pipefd[0]);
 561
 562       p =  strrchr(daemon->lease_change_command, '/');
 563       if (err == 0)
 564         {
 565           execl(daemon->lease_change_command,
 566                 p ? p+1 : daemon->lease_change_command,
 567                 action_str, is6 ? daemon->packet : daemon->dhcp_buff,
 568                 daemon->addrbuff, hostname, (char*)NULL);
 569           err = errno;
 570         }
 571       /* failed, send event so the main process logs the problem */
 572       send_event(event_fd, EVENT_EXEC_ERR, err, NULL);
 573       _exit(0);
 574     }
 575 }
 576
 577 static void my_setenv(const char *name, const char *value, int *error)
 578 {
 579   if (*error == 0)
 580     {
 581       if (!value)
 582         unsetenv(name);
 583       else if (setenv(name, value, 1) != 0)
 584         *error = errno;
 585     }
 586 }
 587
 588 static unsigned char *grab_extradata(unsigned char *buf, unsigned char *end,  char *env, int *err)
 589 {
 590   unsigned char *next = NULL;
 591   char *val = NULL;
 592
 593   if (buf && (buf != end))
 594     {
 595       for (next = buf; ; next++)
 596         if (next == end)
 597           {
 598             next = NULL;
 599             break;
 600           }
 601         else if (*next == 0)
 602           break;
 603
 604       if (next && (next != buf))
 605         {
 606           char *p;
 607           /* No "=" in value */
 608           if ((p = strchr((char *)buf, '=')))
 609             *p = 0;
 610           val = (char *)buf;
 611         }
 612     }
 613
 614   my_setenv(env, val, err);
 615
 616   return next ? next + 1 : NULL;
 617 }
 618
 619 #ifdef HAVE_LUASCRIPT
 620 static unsigned char *grab_extradata_lua(unsigned char *buf, unsigned char *end, char *field)
 621 {
 622   unsigned char *next;
 623
 624   if (!buf || (buf == end))
 625     return NULL;
 626
 627   for (next = buf; *next != 0; next++)
 628     if (next == end)
 629       return NULL;
 630
 631   if (next != buf)
 632     {
 633       lua_pushstring(lua,  (char *)buf);
 634       lua_setfield(lua, -2, field);
 635     }
 636
 637   return next + 1;
 638 }
 639 #endif
 640
 641 static void buff_alloc(size_t size)
 642 {
 643   if (size > buf_size)
 644     {
 645       struct script_data *new;
 646
 647       /* start with reasonable size, will almost never need extending. */
 648       if (size < sizeof(struct script_data) + 200)
 649         size = sizeof(struct script_data) + 200;
 650
 651       if (!(new = whine_malloc(size)))
 652         return;
 653       if (buf)
 654         free(buf);
 655       buf = new;
 656       buf_size = size;
 657     }
 658 }
 659
 660 /* pack up lease data into a buffer */
 661 void queue_script(int action, struct dhcp_lease *lease, char *hostname, time_t now)
 662 {
 663   unsigned char *p;
 664   unsigned int hostname_len = 0, clid_len = 0, ed_len = 0;
 665   int fd = daemon->dhcpfd;
 666 #ifdef HAVE_DHCP6
 667   if (!daemon->dhcp)
 668     fd = daemon->dhcp6fd;
 669 #endif
 670
 671   /* no script */
 672   if (daemon->helperfd == -1)
 673     return;
 674
 675   if (lease->extradata)
 676     ed_len = lease->extradata_len;
 677   if (lease->clid)
 678     clid_len = lease->clid_len;
 679   if (hostname)
 680     hostname_len = strlen(hostname) + 1;
 681
 682   buff_alloc(sizeof(struct script_data) +  clid_len + ed_len + hostname_len);
 683
 684   buf->action = action;
 685   buf->flags = lease->flags;
 686 #ifdef HAVE_DHCP6
 687   buf->vendorclass_count = lease->vendorclass_count;
 688   buf->addr6 = lease->addr6;
 689   buf->iaid = lease->iaid;
 690 #endif
 691   buf->hwaddr_len = lease->hwaddr_len;
 692   buf->hwaddr_type = lease->hwaddr_type;
 693   buf->clid_len = clid_len;
 694   buf->ed_len = ed_len;
 695   buf->hostname_len = hostname_len;
 696   buf->addr = lease->addr;
 697   buf->giaddr = lease->giaddr;
 698   memcpy(buf->hwaddr, lease->hwaddr, DHCP_CHADDR_MAX);
 699   if (!indextoname(fd, lease->last_interface, buf->interface))
 700     buf->interface[0] = 0;
 701
 702 #ifdef HAVE_BROKEN_RTC
 703   buf->length = lease->length;
 704 #else
 705   buf->expires = lease->expires;
 706 #endif
 707
 708   if (lease->expires != 0)
 709     buf->remaining_time = (unsigned int)difftime(lease->expires, now);
 710   else
 711     buf->remaining_time = 0;
 712
 713   p = (unsigned char *)(buf+1);
 714   if (clid_len != 0)
 715     {
 716       memcpy(p, lease->clid, clid_len);
 717       p += clid_len;
 718     }
 719   if (hostname_len != 0)
 720     {
 721       memcpy(p, hostname, hostname_len);
 722       p += hostname_len;
 723     }
 724   if (ed_len != 0)
 725     {
 726       memcpy(p, lease->extradata, ed_len);
 727       p += ed_len;
 728     }
 729   bytes_in_buf = p - (unsigned char *)buf;
 730 }
 731
 732 #ifdef HAVE_TFTP
 733 /* This nastily re-uses DHCP-fields for TFTP stuff */
 734 void queue_tftp(off_t file_len, char *filename, union mysockaddr *peer)
 735 {
 736   unsigned int filename_len;
 737
 738   /* no script */
 739   if (daemon->helperfd == -1)
 740     return;
 741
 742   filename_len = strlen(filename) + 1;
 743   buff_alloc(sizeof(struct script_data) +  filename_len);
 744   memset(buf, 0, sizeof(struct script_data));
 745
 746   buf->action = ACTION_TFTP;
 747   buf->hostname_len = filename_len;
 748   buf->file_len = file_len;
 749
 750   if ((buf->flags = peer->sa.sa_family) == AF_INET)
 751     buf->addr = peer->in.sin_addr;
 752 #ifdef HAVE_IPV6
 753   else
 754     buf->addr6 = peer->in6.sin6_addr;
 755 #endif
 756
 757   memcpy((unsigned char *)(buf+1), filename, filename_len);
 758
 759   bytes_in_buf = sizeof(struct script_data) +  filename_len;
 760 }
 761 #endif
 762
 763 int helper_buf_empty(void)
 764 {
 765   return bytes_in_buf == 0;
 766 }
 767
 768 void helper_write(void)
 769 {
 770   ssize_t rc;
 771
 772   if (bytes_in_buf == 0)
 773     return;
 774
 775   if ((rc = write(daemon->helperfd, buf, bytes_in_buf)) != -1)
 776     {
 777       if (bytes_in_buf != (size_t)rc)
 778         memmove(buf, buf + rc, bytes_in_buf - rc);
 779       bytes_in_buf -= rc;
 780     }
 781   else
 782     {
 783       if (errno == EAGAIN || errno == EINTR)
 784         return;
 785       bytes_in_buf = 0;
 786     }
 787 }
 788
 789 #endif
 790
 791
 792