client_common.c

   1 /*
   2  * Copyright (C) 1997-2013 Andre Noll <maan@systemlinux.org>
   3  *
   4  * Licensed under the GPL v2. For licencing details see COPYING.
   5  */
   6
   7 /** \file client_common.c Common functions of para_client and para_audiod. */
   8
   9 #include <regex.h>
  10 #include <sys/types.h>
  11
  12 #include "para.h"
  13 #include "error.h"
  14 #include "list.h"
  15 #include "sched.h"
  16 #include "client.cmdline.h"
  17 #include "crypt.h"
  18 #include "net.h"
  19 #include "fd.h"
  20 #include "sideband.h"
  21 #include "string.h"
  22 #include "client.cmdline.h"
  23 #include "client.h"
  24 #include "buffer_tree.h"
  25 #include "version.h"
  26
  27 /** The size of the receiving buffer. */
  28 #define CLIENT_BUFSIZE 4000
  29
  30 /**
  31  * Close the connection to para_server and deallocate per-command ressources.
  32  *
  33  * \param ct The client task.
  34  *
  35  * This frees all ressources of the current command but keeps the configuration
  36  * in \p ct->conf.
  37  *
  38  * \sa \ref client_close().
  39  */
  40 void client_disconnect(struct client_task *ct)
  41 {
  42         if (!ct)
  43                 return;
  44         if (ct->scc.fd >= 0)
  45                 close(ct->scc.fd);
  46         free_argv(ct->features);
  47         ct->features = NULL;
  48         sc_free(ct->scc.recv);
  49         ct->scc.recv = NULL;
  50         sc_free(ct->scc.send);
  51         ct->scc.send = NULL;
  52         btr_remove_node(&ct->btrn);
  53 }
  54
  55 /**
  56  * Close the connection to para_server and free all resources.
  57  *
  58  * \param ct Pointer to the client data.
  59  *
  60  * \sa \ref client_open(), \ref client_disconnect().
  61  */
  62 void client_close(struct client_task *ct)
  63 {
  64         if (!ct)
  65                 return;
  66         client_disconnect(ct);
  67         free(ct->user);
  68         free(ct->config_file);
  69         free(ct->key_file);
  70         client_cmdline_parser_free(&ct->conf);
  71         free(ct->challenge_hash);
  72         sb_free(ct->sbc);
  73         free(ct);
  74 }
  75
  76 /**
  77  * The preselect hook for server commands.
  78  *
  79  * \param s Pointer to the scheduler.
  80  * \param t Pointer to the task struct for this command.
  81  *
  82  * The task pointer must contain a pointer to the initialized client data
  83  * structure as it is returned by client_open().
  84  *
  85  * This function checks the state of the connection and adds the file descriptor
  86  * of the connection to the read or write fd set of \a s accordingly.
  87  *
  88  * \sa register_task() client_open(), struct sched, struct task.
  89  */
  90 static void client_pre_select(struct sched *s, struct task *t)
  91 {
  92         int ret;
  93         struct client_task *ct = container_of(t, struct client_task, task);
  94         struct btr_node *btrn = ct->btrn;
  95
  96         if (ct->scc.fd < 0)
  97                 return;
  98         switch (ct->status) {
  99         case CL_CONNECTED:
 100         case CL_SENT_AUTH:
 101         case CL_SENT_CH_RESPONSE:
 102         case CL_SENT_COMMAND:
 103                 para_fd_set(ct->scc.fd, &s->rfds, &s->max_fileno);
 104                 return;
 105
 106         case CL_RECEIVED_WELCOME:
 107         case CL_RECEIVED_PROCEED:
 108         case CL_RECEIVED_CHALLENGE:
 109                 para_fd_set(ct->scc.fd, &s->wfds, &s->max_fileno);
 110                 return;
 111
 112         case CL_RECEIVING:
 113                 ret = btr_node_status(btrn, 0, BTR_NT_ROOT);
 114                 if (ret != 0) {
 115                         if (ret < 0)
 116                                 sched_min_delay(s);
 117                         else
 118                                 para_fd_set(ct->scc.fd, &s->rfds,
 119                                         &s->max_fileno);
 120                 }
 121                 return;
 122         case CL_SENDING:
 123                 ret = btr_node_status(btrn, 0, BTR_NT_LEAF);
 124                 if (ret != 0) {
 125                         if (ret < 0)
 126                                 sched_min_delay(s);
 127                         else
 128                                 para_fd_set(ct->scc.fd, &s->wfds,
 129                                         &s->max_fileno);
 130                 }
 131                 return;
 132         }
 133 }
 134
 135 static int client_recv_buffer(struct client_task *ct, fd_set *rfds,
 136                 char *buf, size_t sz, size_t *n)
 137 {
 138         int ret;
 139
 140         if (ct->status < CL_SENT_CH_RESPONSE)
 141                 return read_nonblock(ct->scc.fd, buf, sz, rfds, n);
 142
 143         *n = 0;
 144         ret = sc_recv_buffer(&ct->scc, buf, sz);
 145         /*
 146          * sc_recv_buffer is used with blocking fds elsewhere, so it
 147          * does not use the nonblock-API. Therefore we need to
 148          * check for EOF and EAGAIN.
 149          */
 150         if (ret == 0)
 151                 return -E_SERVER_EOF;
 152         if (ret == -ERRNO_TO_PARA_ERROR(EAGAIN))
 153                 return 0;
 154         if (ret < 0)
 155                 return ret;
 156         *n = ret;
 157         return 0;
 158 }
 159
 160 static int send_sb(struct client_task *ct, void *buf, size_t numbytes,
 161                 enum sb_designator band, bool dont_free)
 162 {
 163         int ret, fd = ct->scc.fd;
 164         struct iovec iov[2];
 165
 166         if (!ct->sbc) {
 167                 struct sb_buffer sbb;
 168                 sb_transformation trafo = ct->status < CL_RECEIVED_PROCEED?
 169                         NULL : sc_trafo;
 170                 sbb = (typeof(sbb))SBB_INIT(band, buf, numbytes);
 171                 ct->sbc = sb_new_send(&sbb, dont_free, trafo, ct->scc.send);
 172         }
 173         ret = sb_get_send_buffers(ct->sbc, iov);
 174         ret = xwritev(fd, iov, ret);
 175         if (ret < 0) {
 176                 sb_free(ct->sbc);
 177                 ct->sbc = NULL;
 178                 return ret;
 179         }
 180         if (sb_sent(ct->sbc, ret)) {
 181                 ct->sbc = NULL;
 182                 return 1;
 183         }
 184         return 0;
 185 }
 186
 187 static int recv_sb(struct client_task *ct, fd_set *rfds,
 188                 struct sb_buffer *result)
 189 {
 190         int ret;
 191         size_t n;
 192         sb_transformation trafo;
 193         void *trafo_context;
 194         struct iovec iov;
 195
 196         if (!FD_ISSET(ct->scc.fd, rfds))
 197                 return 0;
 198         if (ct->status < CL_SENT_CH_RESPONSE)
 199                 trafo = trafo_context = NULL;
 200         else {
 201                 trafo = sc_trafo;
 202                 trafo_context = ct->scc.recv;
 203         }
 204         if (!ct->sbc)
 205                 ct->sbc = sb_new_recv(0, trafo, trafo_context);
 206 again:
 207         sb_get_recv_buffer(ct->sbc, &iov);
 208         ret = read_nonblock(ct->scc.fd, iov.iov_base, iov.iov_len, rfds, &n);
 209         if (ret < 0) {
 210                 sb_free(ct->sbc);
 211                 ct->sbc = NULL;
 212                 return ret;
 213         }
 214         if (n == 0)
 215                 return 0;
 216         if (!sb_received(ct->sbc, n, result))
 217                 goto again;
 218         ct->sbc = NULL;
 219         return 1;
 220 }
 221
 222
 223 static char **parse_features(char *buf)
 224 {
 225         int i;
 226         const char id[] = "\nFeatures: ";
 227         char *p, *q, **features;
 228
 229         p = strstr(buf, id);
 230         if (!p)
 231                 return NULL;
 232         p += strlen(id);
 233         q = strchr(p, '\n');
 234         if (!q)
 235                 return NULL;
 236         *q = '\0';
 237         create_argv(p, ",", &features);
 238         for (i = 0; features[i]; i++)
 239                 PARA_INFO_LOG("server feature: %s\n", features[i]);
 240         return features;
 241 }
 242
 243 static int dispatch_sbb(struct client_task *ct, struct sb_buffer *sbb)
 244 {
 245         int ret;
 246         const char *designator[] = {SB_DESIGNATORS_ARRAY};
 247
 248         if (!sbb)
 249                 return 0;
 250         if (sbb->band < NUM_SB_DESIGNATORS)
 251                 PARA_DEBUG_LOG("band: %s\n", designator[sbb->band]);
 252
 253         switch (sbb->band) {
 254         case SBD_OUTPUT:
 255                 if (iov_valid(&sbb->iov))
 256                         btr_add_output(sbb->iov.iov_base, sbb->iov.iov_len,
 257                                 ct->btrn);
 258                 ret = 1;
 259                 goto out;
 260         case SBD_DEBUG_LOG:
 261         case SBD_INFO_LOG:
 262         case SBD_NOTICE_LOG:
 263         case SBD_WARNING_LOG:
 264         case SBD_ERROR_LOG:
 265         case SBD_CRIT_LOG:
 266         case SBD_EMERG_LOG:
 267                 if (iov_valid(&sbb->iov)) {
 268                         int ll = sbb->band - SBD_DEBUG_LOG;
 269                         para_log(ll, "remote: %s", (char *)sbb->iov.iov_base);
 270                 }
 271                 ret = 1;
 272                 goto deallocate;
 273         case SBD_EXIT__SUCCESS:
 274                 ret = -E_SERVER_CMD_SUCCESS;
 275                 goto deallocate;
 276         case SBD_EXIT__FAILURE:
 277                 ret = -E_SERVER_CMD_FAILURE;
 278                 goto deallocate;
 279         default:
 280                 PARA_ERROR_LOG("invalid band %d\n", sbb->band);
 281                 ret = -E_BAD_BAND;
 282                 goto deallocate;
 283         }
 284 deallocate:
 285         free(sbb->iov.iov_base);
 286 out:
 287         sbb->iov.iov_base = NULL;
 288         return ret;
 289 }
 290
 291 static bool has_feature(const char *feature, struct client_task *ct)
 292 {
 293         return find_arg(feature, ct->features) >= 0? true : false;
 294 }
 295
 296 static int send_sb_command(struct client_task *ct)
 297 {
 298         int i;
 299         char *command, *p;
 300         size_t len = 0;
 301
 302         if (ct->sbc)
 303                 return send_sb(ct, NULL, 0, 0, false);
 304
 305         for (i = 0; i < ct->conf.inputs_num; i++)
 306                 len += strlen(ct->conf.inputs[i]) + 1;
 307         p = command = para_malloc(len);
 308         for (i = 0; i < ct->conf.inputs_num; i++) {
 309                 strcpy(p, ct->conf.inputs[i]);
 310                 p += strlen(ct->conf.inputs[i]) + 1;
 311         }
 312         PARA_DEBUG_LOG("--> %s\n", command);
 313         return send_sb(ct, command, len, SBD_COMMAND, false);
 314 }
 315
 316 /**
 317  * The post select hook for client commands.
 318  *
 319  * \param s Pointer to the scheduler.
 320  * \param t Pointer to the task struct for this command.
 321  *
 322  * Depending on the current state of the connection and the status of the read
 323  * and write fd sets of \a s, this function performs the necessary steps to
 324  * authenticate the connection, to send the command given by \a t->private_data
 325  * and to receive para_server's output, if any.
 326  *
 327  * \sa struct sched, struct task.
 328  */
 329 static void client_post_select(struct sched *s, struct task *t)
 330 {
 331         struct client_task *ct = container_of(t, struct client_task, task);
 332         struct btr_node *btrn = ct->btrn;
 333         int ret = 0;
 334         size_t n;
 335         char buf[CLIENT_BUFSIZE];
 336
 337         ret = task_get_notification(t);
 338         if (ret < 0)
 339                 goto out;
 340         if (ct->scc.fd < 0)
 341                 return;
 342         switch (ct->status) {
 343         case CL_CONNECTED: /* receive welcome message */
 344                 ret = client_recv_buffer(ct, &s->rfds, buf, sizeof(buf), &n);
 345                 if (ret < 0 || n == 0)
 346                         goto out;
 347                 ct->features = parse_features(buf);
 348                 if (!has_feature("sideband", ct)) {
 349                         PARA_ERROR_LOG("server has no sideband support\n");
 350                         ret = -E_INCOMPAT_FEAT;
 351                         goto out;
 352                 }
 353                 ct->status = CL_RECEIVED_WELCOME;
 354                 return;
 355         case CL_RECEIVED_WELCOME: /* send auth command */
 356                 if (!FD_ISSET(ct->scc.fd, &s->wfds))
 357                         return;
 358                 sprintf(buf, AUTH_REQUEST_MSG "%s sideband", ct->user);
 359                 PARA_INFO_LOG("--> %s\n", buf);
 360                 ret = write_buffer(ct->scc.fd, buf);
 361                 if (ret < 0)
 362                         goto out;
 363                 ct->status = CL_SENT_AUTH;
 364                 return;
 365         case CL_SENT_AUTH:
 366                 /*
 367                  * Receive challenge and session keys, decrypt the challenge and
 368                  * send back the hash of the decrypted challenge.
 369                  */
 370                 {
 371                 /* decrypted challenge/session key buffer */
 372                 unsigned char crypt_buf[1024];
 373                 struct sb_buffer sbb;
 374
 375                 ret = recv_sb(ct, &s->rfds, &sbb);
 376                 if (ret <= 0)
 377                         goto out;
 378                 if (sbb.band != SBD_CHALLENGE) {
 379                         ret = -E_BAD_BAND;
 380                         free(sbb.iov.iov_base);
 381                                 goto out;
 382                 }
 383                 n = sbb.iov.iov_len;
 384                 PARA_INFO_LOG("<-- [challenge] (%zu bytes)\n", n);
 385                 ret = priv_decrypt(ct->key_file, crypt_buf,
 386                         sbb.iov.iov_base, n);
 387                 free(sbb.iov.iov_base);
 388                 if (ret < 0)
 389                         goto out;
 390                 ct->challenge_hash = para_malloc(HASH_SIZE);
 391                 hash_function((char *)crypt_buf, CHALLENGE_SIZE, ct->challenge_hash);
 392                 ct->scc.send = sc_new(crypt_buf + CHALLENGE_SIZE, SESSION_KEY_LEN);
 393                 ct->scc.recv = sc_new(crypt_buf + CHALLENGE_SIZE + SESSION_KEY_LEN,
 394                         SESSION_KEY_LEN);
 395                 hash_to_asc(ct->challenge_hash, buf);
 396                 PARA_INFO_LOG("--> %s\n", buf);
 397                 ct->status = CL_RECEIVED_CHALLENGE;
 398                 return;
 399                 }
 400         case CL_RECEIVED_CHALLENGE:
 401                 ret = send_sb(ct, ct->challenge_hash, HASH_SIZE,
 402                         SBD_CHALLENGE_RESPONSE, false);
 403                 if (ret != 0)
 404                         ct->challenge_hash = NULL;
 405                 if (ret <= 0)
 406                         goto out;
 407                 ct->status = CL_SENT_CH_RESPONSE;
 408                 goto out;
 409         case CL_SENT_CH_RESPONSE: /* read server response */
 410                 {
 411                 struct sb_buffer sbb;
 412                 ret = recv_sb(ct, &s->rfds, &sbb);
 413                 if (ret <= 0)
 414                         goto out;
 415                 free(sbb.iov.iov_base);
 416                 if (sbb.band != SBD_PROCEED)
 417                         ret = -E_BAD_BAND;
 418                 else
 419                         ct->status = CL_RECEIVED_PROCEED;
 420                 goto out;
 421                 }
 422         case CL_RECEIVED_PROCEED: /* concat args and send command */
 423                 {
 424                 if (!FD_ISSET(ct->scc.fd, &s->wfds))
 425                         return;
 426                 ret = send_sb_command(ct);
 427                 if (ret <= 0)
 428                         goto out;
 429                 ct->status = CL_SENT_COMMAND;
 430                 return;
 431                 }
 432         case CL_SENT_COMMAND:
 433                 {
 434                 struct sb_buffer sbb;
 435                 ret = recv_sb(ct, &s->rfds, &sbb);
 436                 if (ret <= 0)
 437                         goto out;
 438                 if (sbb.band == SBD_AWAITING_DATA) {
 439                         ct->status = CL_SENDING;
 440                         free(sbb.iov.iov_base);
 441                         goto out;
 442                 }
 443                 ct->status = CL_RECEIVING;
 444                 ret = dispatch_sbb(ct, &sbb);
 445                 goto out;
 446                 }
 447         case CL_SENDING:
 448                 {
 449                 char *buf2;
 450                 size_t sz;
 451                 ret = btr_node_status(btrn, 0, BTR_NT_LEAF);
 452                 if (ret < 0)
 453                         goto out;
 454                 if (ret == 0)
 455                         return;
 456                 if (!FD_ISSET(ct->scc.fd, &s->wfds))
 457                         return;
 458                 sz = btr_next_buffer(btrn, &buf2);
 459                 ret = sc_send_bin_buffer(&ct->scc, buf2, sz);
 460                 if (ret < 0)
 461                         goto out;
 462                 btr_consume(btrn, sz);
 463                 return;
 464                 }
 465         case CL_RECEIVING:
 466                 {
 467                 struct sb_buffer sbb;
 468                 ret = btr_node_status(btrn, 0, BTR_NT_ROOT);
 469                 if (ret < 0)
 470                         goto out;
 471                 if (ret == 0)
 472                         return;
 473                 /*
 474                  * The FD_ISSET() is not strictly necessary, but is allows us
 475                  * to skip the malloc below if there is nothing to read anyway.
 476                  */
 477                 if (!FD_ISSET(ct->scc.fd, &s->rfds))
 478                         return;
 479                 ret = recv_sb(ct, &s->rfds, &sbb);
 480                 if (ret > 0)
 481                         ret = dispatch_sbb(ct, &sbb);
 482                 goto out;
 483                 }
 484         }
 485 out:
 486         t->error = ret;
 487         if (ret < 0)
 488                 btr_remove_node(&ct->btrn);
 489 }
 490
 491 /**
 492  * Connect to para_server and register the client task.
 493  *
 494  * \param ct The initialized client task structure.
 495  * \param s The scheduler instance to register the client task to.
 496  * \param parent The parent node of the client btr node.
 497  * \param child The child node of the client node.
 498  *
 499  * The client task structure given by \a ct  must be allocated and initialized
 500  * by \ref client_parse_config() before this function is called.
 501  *
 502  * \return Standard.
 503  */
 504 int client_connect(struct client_task *ct, struct sched *s,
 505                 struct btr_node *parent, struct btr_node *child)
 506 {
 507         int ret;
 508
 509         PARA_NOTICE_LOG("connecting %s:%d\n", ct->conf.hostname_arg,
 510                 ct->conf.server_port_arg);
 511         ct->scc.fd = -1;
 512         ret = para_connect_simple(IPPROTO_TCP, ct->conf.hostname_arg,
 513                                                ct->conf.server_port_arg);
 514         if (ret < 0)
 515                 return ret;
 516         ct->scc.fd = ret;
 517         ret = mark_fd_nonblocking(ct->scc.fd);
 518         if (ret < 0)
 519                 goto err_out;
 520         ct->status = CL_CONNECTED;
 521         ct->btrn = btr_new_node(&(struct btr_node_description)
 522                 EMBRACE(.name = "client", .parent = parent, .child = child));
 523         ct->task.pre_select = client_pre_select;
 524         ct->task.post_select = client_post_select;
 525         ct->task.error = 0;
 526         sprintf(ct->task.status, "client");
 527         register_task(s, &ct->task);
 528         return 1;
 529 err_out:
 530         close(ct->scc.fd);
 531         ct->scc.fd = -1;
 532         return ret;
 533 }
 534
 535 /**
 536  * Parse a client configuration.
 537  *
 538  * \param argc Usual argument count.
 539  * \param argv Usual argument vector.
 540  * \param ct_ptr Filled in by this function.
 541  * \param loglevel If not \p NULL, the number of the loglevel is stored here.
 542  *
 543  * This checks the command line options given by \a argc and \a argv, sets
 544  * default values for the user name and the name of the rsa key file and reads
 545  * further options from the config file.
 546  *
 547  * Upon successful return, \a ct_ptr points to a dynamically allocated and
 548  * initialized client task struct.
 549  *
 550  * \return The number of non-option arguments in \a argc/argv on success,
 551  * negative on errors.
 552  */
 553 int client_parse_config(int argc, char *argv[], struct client_task **ct_ptr,
 554                 int *loglevel)
 555 {
 556         char *home = para_homedir();
 557         int ret;
 558         struct client_task *ct = para_calloc(sizeof(struct client_task));
 559
 560         *ct_ptr = ct;
 561         ct->scc.fd = -1;
 562         ret = -E_CLIENT_SYNTAX;
 563         if (client_cmdline_parser(argc, argv, &ct->conf))
 564                 goto out;
 565         HANDLE_VERSION_FLAG("client", ct->conf);
 566
 567         ct->config_file = ct->conf.config_file_given?
 568                 para_strdup(ct->conf.config_file_arg) :
 569                 make_message("%s/.paraslash/client.conf", home);
 570         ret = file_exists(ct->config_file);
 571         if (!ret && ct->conf.config_file_given) {
 572                 ret = -E_NO_CONFIG;
 573                 goto out;
 574         }
 575         if (ret) {
 576                 struct client_cmdline_parser_params params = {
 577                         .override = 0,
 578                         .initialize = 0,
 579                         .check_required = 0,
 580                         .check_ambiguity = 0,
 581                         .print_errors = 0
 582                 };
 583                 ret = -E_BAD_CONFIG;
 584                 if (client_cmdline_parser_config_file(ct->config_file,
 585                         &ct->conf, &params))
 586                         goto out;
 587         }
 588         ct->user = ct->conf.user_given?
 589                 para_strdup(ct->conf.user_arg) : para_logname();
 590
 591         if (ct->conf.key_file_given)
 592                 ct->key_file = para_strdup(ct->conf.key_file_arg);
 593         else {
 594                 ct->key_file = make_message("%s/.paraslash/key.%s",
 595                         home, ct->user);
 596                 if (!file_exists(ct->key_file)) {
 597                         free(ct->key_file);
 598                         ct->key_file = make_message("%s/.ssh/id_rsa", home);
 599                 }
 600         }
 601
 602         if (loglevel)
 603                 *loglevel = get_loglevel_by_name(ct->conf.loglevel_arg);
 604         PARA_INFO_LOG("loglevel: %s\n", ct->conf.loglevel_arg);
 605         PARA_INFO_LOG("config_file: %s\n", ct->config_file);
 606         PARA_INFO_LOG("key_file: %s\n", ct->key_file);
 607         ret = ct->conf.inputs_num;
 608 out:
 609         free(home);
 610         if (ret < 0) {
 611                 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
 612                 client_close(ct);
 613                 *ct_ptr = NULL;
 614         }
 615         return ret;
 616 }
 617
 618 /**
 619  * Parse the client configuration and open a connection to para_server.
 620  *
 621  * \param argc See \ref client_parse_config.
 622  * \param argv See \ref client_parse_config.
 623  * \param ct_ptr See \ref client_parse_config.
 624  * \param loglevel See \ref client_parse_config.
 625  * \param parent See \ref client_connect().
 626  * \param child See \ref client_connect().
 627  * \param sched See \ref client_connect().
 628  *
 629  * This function combines client_parse_config() and client_connect(). It is
 630  * considered a syntax error if no command was given, i.e. if the number
 631  * of non-option arguments is zero.
 632  *
 633  * \return Standard.
 634  */
 635 int client_open(int argc, char *argv[], struct client_task **ct_ptr,
 636                 int *loglevel, struct btr_node *parent, struct btr_node *child,
 637                 struct sched *sched)
 638 {
 639         int ret = client_parse_config(argc, argv, ct_ptr, loglevel);
 640
 641         if (ret < 0)
 642                 return ret;
 643         if (ret == 0) {
 644                 ret = -E_CLIENT_SYNTAX;
 645                 goto fail;
 646         }
 647         ret = client_connect(*ct_ptr, sched, parent, child);
 648         if (ret < 0)
 649                 goto fail;
 650         return 1;
 651 fail:
 652         client_close(*ct_ptr);
 653         *ct_ptr = NULL;
 654         return ret;
 655 }