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 send_sb(struct client_task *ct, void *buf, size_t numbytes,
 136                 enum sb_designator band, bool dont_free)
 137 {
 138         int ret, fd = ct->scc.fd;
 139         struct iovec iov[2];
 140
 141         if (!ct->sbc) {
 142                 struct sb_buffer sbb;
 143                 sb_transformation trafo = ct->status < CL_RECEIVED_PROCEED?
 144                         NULL : sc_trafo;
 145                 sbb = (typeof(sbb))SBB_INIT(band, buf, numbytes);
 146                 ct->sbc = sb_new_send(&sbb, dont_free, trafo, ct->scc.send);
 147         }
 148         ret = sb_get_send_buffers(ct->sbc, iov);
 149         ret = xwritev(fd, iov, ret);
 150         if (ret < 0) {
 151                 sb_free(ct->sbc);
 152                 ct->sbc = NULL;
 153                 return ret;
 154         }
 155         if (sb_sent(ct->sbc, ret)) {
 156                 ct->sbc = NULL;
 157                 return 1;
 158         }
 159         return 0;
 160 }
 161
 162 static int recv_sb(struct client_task *ct, fd_set *rfds,
 163                 struct sb_buffer *result)
 164 {
 165         int ret;
 166         size_t n;
 167         sb_transformation trafo;
 168         void *trafo_context;
 169         struct iovec iov;
 170
 171         if (!FD_ISSET(ct->scc.fd, rfds))
 172                 return 0;
 173         if (ct->status < CL_SENT_CH_RESPONSE)
 174                 trafo = trafo_context = NULL;
 175         else {
 176                 trafo = sc_trafo;
 177                 trafo_context = ct->scc.recv;
 178         }
 179         if (!ct->sbc)
 180                 ct->sbc = sb_new_recv(0, trafo, trafo_context);
 181 again:
 182         sb_get_recv_buffer(ct->sbc, &iov);
 183         ret = read_nonblock(ct->scc.fd, iov.iov_base, iov.iov_len, rfds, &n);
 184         if (ret < 0) {
 185                 sb_free(ct->sbc);
 186                 ct->sbc = NULL;
 187                 return ret;
 188         }
 189         if (n == 0)
 190                 return 0;
 191         if (!sb_received(ct->sbc, n, result))
 192                 goto again;
 193         ct->sbc = NULL;
 194         return 1;
 195 }
 196
 197
 198 static char **parse_features(char *buf)
 199 {
 200         int i;
 201         const char id[] = "\nFeatures: ";
 202         char *p, *q, **features;
 203
 204         p = strstr(buf, id);
 205         if (!p)
 206                 return NULL;
 207         p += strlen(id);
 208         q = strchr(p, '\n');
 209         if (!q)
 210                 return NULL;
 211         *q = '\0';
 212         create_argv(p, ",", &features);
 213         for (i = 0; features[i]; i++)
 214                 PARA_INFO_LOG("server feature: %s\n", features[i]);
 215         return features;
 216 }
 217
 218 static int dispatch_sbb(struct client_task *ct, struct sb_buffer *sbb)
 219 {
 220         int ret;
 221         const char *designator[] = {SB_DESIGNATORS_ARRAY};
 222
 223         if (!sbb)
 224                 return 0;
 225         if (sbb->band < NUM_SB_DESIGNATORS)
 226                 PARA_DEBUG_LOG("band: %s\n", designator[sbb->band]);
 227
 228         switch (sbb->band) {
 229         case SBD_OUTPUT:
 230                 if (iov_valid(&sbb->iov))
 231                         btr_add_output(sbb->iov.iov_base, sbb->iov.iov_len,
 232                                 ct->btrn);
 233                 ret = 1;
 234                 goto out;
 235         case SBD_DEBUG_LOG:
 236         case SBD_INFO_LOG:
 237         case SBD_NOTICE_LOG:
 238         case SBD_WARNING_LOG:
 239         case SBD_ERROR_LOG:
 240         case SBD_CRIT_LOG:
 241         case SBD_EMERG_LOG:
 242                 if (iov_valid(&sbb->iov)) {
 243                         int ll = sbb->band - SBD_DEBUG_LOG;
 244                         para_log(ll, "remote: %s", (char *)sbb->iov.iov_base);
 245                 }
 246                 ret = 1;
 247                 goto deallocate;
 248         case SBD_EXIT__SUCCESS:
 249                 ret = -E_SERVER_CMD_SUCCESS;
 250                 goto deallocate;
 251         case SBD_EXIT__FAILURE:
 252                 ret = -E_SERVER_CMD_FAILURE;
 253                 goto deallocate;
 254         default:
 255                 PARA_ERROR_LOG("invalid band %d\n", sbb->band);
 256                 ret = -E_BAD_BAND;
 257                 goto deallocate;
 258         }
 259 deallocate:
 260         free(sbb->iov.iov_base);
 261 out:
 262         sbb->iov.iov_base = NULL;
 263         return ret;
 264 }
 265
 266 static bool has_feature(const char *feature, struct client_task *ct)
 267 {
 268         return find_arg(feature, ct->features) >= 0? true : false;
 269 }
 270
 271 static int send_sb_command(struct client_task *ct)
 272 {
 273         int i;
 274         char *command, *p;
 275         size_t len = 0;
 276
 277         if (ct->sbc)
 278                 return send_sb(ct, NULL, 0, 0, false);
 279
 280         for (i = 0; i < ct->conf.inputs_num; i++)
 281                 len += strlen(ct->conf.inputs[i]) + 1;
 282         p = command = para_malloc(len);
 283         for (i = 0; i < ct->conf.inputs_num; i++) {
 284                 strcpy(p, ct->conf.inputs[i]);
 285                 p += strlen(ct->conf.inputs[i]) + 1;
 286         }
 287         PARA_DEBUG_LOG("--> %s\n", command);
 288         return send_sb(ct, command, len, SBD_COMMAND, false);
 289 }
 290
 291 /**
 292  * The post select hook for client commands.
 293  *
 294  * \param s Pointer to the scheduler.
 295  * \param t Pointer to the task struct for this command.
 296  *
 297  * Depending on the current state of the connection and the status of the read
 298  * and write fd sets of \a s, this function performs the necessary steps to
 299  * authenticate the connection, to send the command given by \a t->private_data
 300  * and to receive para_server's output, if any.
 301  *
 302  * \sa struct sched, struct task.
 303  */
 304 static void client_post_select(struct sched *s, struct task *t)
 305 {
 306         struct client_task *ct = container_of(t, struct client_task, task);
 307         struct btr_node *btrn = ct->btrn;
 308         int ret = 0;
 309         size_t n;
 310         char buf[CLIENT_BUFSIZE];
 311
 312         ret = task_get_notification(t);
 313         if (ret < 0)
 314                 goto out;
 315         if (ct->scc.fd < 0)
 316                 return;
 317         switch (ct->status) {
 318         case CL_CONNECTED: /* receive welcome message */
 319                 ret = read_nonblock(ct->scc.fd, buf, sizeof(buf), &s->rfds, &n);
 320                 if (ret < 0 || n == 0)
 321                         goto out;
 322                 ct->features = parse_features(buf);
 323                 if (!has_feature("sideband", ct)) {
 324                         PARA_ERROR_LOG("server has no sideband support\n");
 325                         ret = -E_INCOMPAT_FEAT;
 326                         goto out;
 327                 }
 328                 ct->status = CL_RECEIVED_WELCOME;
 329                 return;
 330         case CL_RECEIVED_WELCOME: /* send auth command */
 331                 if (!FD_ISSET(ct->scc.fd, &s->wfds))
 332                         return;
 333                 sprintf(buf, AUTH_REQUEST_MSG "%s sideband", ct->user);
 334                 PARA_INFO_LOG("--> %s\n", buf);
 335                 ret = write_buffer(ct->scc.fd, buf);
 336                 if (ret < 0)
 337                         goto out;
 338                 ct->status = CL_SENT_AUTH;
 339                 return;
 340         case CL_SENT_AUTH:
 341                 /*
 342                  * Receive challenge and session keys, decrypt the challenge and
 343                  * send back the hash of the decrypted challenge.
 344                  */
 345                 {
 346                 /* decrypted challenge/session key buffer */
 347                 unsigned char crypt_buf[1024];
 348                 struct sb_buffer sbb;
 349
 350                 ret = recv_sb(ct, &s->rfds, &sbb);
 351                 if (ret <= 0)
 352                         goto out;
 353                 if (sbb.band != SBD_CHALLENGE) {
 354                         ret = -E_BAD_BAND;
 355                         free(sbb.iov.iov_base);
 356                                 goto out;
 357                 }
 358                 n = sbb.iov.iov_len;
 359                 PARA_INFO_LOG("<-- [challenge] (%zu bytes)\n", n);
 360                 ret = priv_decrypt(ct->key_file, crypt_buf,
 361                         sbb.iov.iov_base, n);
 362                 free(sbb.iov.iov_base);
 363                 if (ret < 0)
 364                         goto out;
 365                 ct->challenge_hash = para_malloc(HASH_SIZE);
 366                 hash_function((char *)crypt_buf, CHALLENGE_SIZE, ct->challenge_hash);
 367                 ct->scc.send = sc_new(crypt_buf + CHALLENGE_SIZE, SESSION_KEY_LEN);
 368                 ct->scc.recv = sc_new(crypt_buf + CHALLENGE_SIZE + SESSION_KEY_LEN,
 369                         SESSION_KEY_LEN);
 370                 hash_to_asc(ct->challenge_hash, buf);
 371                 PARA_INFO_LOG("--> %s\n", buf);
 372                 ct->status = CL_RECEIVED_CHALLENGE;
 373                 return;
 374                 }
 375         case CL_RECEIVED_CHALLENGE:
 376                 ret = send_sb(ct, ct->challenge_hash, HASH_SIZE,
 377                         SBD_CHALLENGE_RESPONSE, false);
 378                 if (ret != 0)
 379                         ct->challenge_hash = NULL;
 380                 if (ret <= 0)
 381                         goto out;
 382                 ct->status = CL_SENT_CH_RESPONSE;
 383                 goto out;
 384         case CL_SENT_CH_RESPONSE: /* read server response */
 385                 {
 386                 struct sb_buffer sbb;
 387                 ret = recv_sb(ct, &s->rfds, &sbb);
 388                 if (ret <= 0)
 389                         goto out;
 390                 free(sbb.iov.iov_base);
 391                 if (sbb.band != SBD_PROCEED)
 392                         ret = -E_BAD_BAND;
 393                 else
 394                         ct->status = CL_RECEIVED_PROCEED;
 395                 goto out;
 396                 }
 397         case CL_RECEIVED_PROCEED: /* concat args and send command */
 398                 {
 399                 if (!FD_ISSET(ct->scc.fd, &s->wfds))
 400                         return;
 401                 ret = send_sb_command(ct);
 402                 if (ret <= 0)
 403                         goto out;
 404                 ct->status = CL_SENT_COMMAND;
 405                 return;
 406                 }
 407         case CL_SENT_COMMAND:
 408                 {
 409                 struct sb_buffer sbb;
 410                 ret = recv_sb(ct, &s->rfds, &sbb);
 411                 if (ret <= 0)
 412                         goto out;
 413                 if (sbb.band == SBD_AWAITING_DATA) {
 414                         ct->status = CL_SENDING;
 415                         free(sbb.iov.iov_base);
 416                         goto out;
 417                 }
 418                 ct->status = CL_RECEIVING;
 419                 ret = dispatch_sbb(ct, &sbb);
 420                 goto out;
 421                 }
 422         case CL_SENDING:
 423                 {
 424                 char *buf2;
 425                 size_t sz;
 426                 ret = btr_node_status(btrn, 0, BTR_NT_LEAF);
 427                 if (ret < 0)
 428                         goto out;
 429                 if (ret == 0)
 430                         return;
 431                 if (!FD_ISSET(ct->scc.fd, &s->wfds))
 432                         return;
 433                 sz = btr_next_buffer(btrn, &buf2);
 434                 ret = sc_send_bin_buffer(&ct->scc, buf2, sz);
 435                 if (ret < 0)
 436                         goto out;
 437                 btr_consume(btrn, sz);
 438                 return;
 439                 }
 440         case CL_RECEIVING:
 441                 {
 442                 struct sb_buffer sbb;
 443                 ret = btr_node_status(btrn, 0, BTR_NT_ROOT);
 444                 if (ret < 0)
 445                         goto out;
 446                 if (ret == 0)
 447                         return;
 448                 /*
 449                  * The FD_ISSET() is not strictly necessary, but is allows us
 450                  * to skip the malloc below if there is nothing to read anyway.
 451                  */
 452                 if (!FD_ISSET(ct->scc.fd, &s->rfds))
 453                         return;
 454                 ret = recv_sb(ct, &s->rfds, &sbb);
 455                 if (ret > 0)
 456                         ret = dispatch_sbb(ct, &sbb);
 457                 goto out;
 458                 }
 459         }
 460 out:
 461         t->error = ret;
 462         if (ret < 0)
 463                 btr_remove_node(&ct->btrn);
 464 }
 465
 466 /**
 467  * Connect to para_server and register the client task.
 468  *
 469  * \param ct The initialized client task structure.
 470  * \param s The scheduler instance to register the client task to.
 471  * \param parent The parent node of the client btr node.
 472  * \param child The child node of the client node.
 473  *
 474  * The client task structure given by \a ct  must be allocated and initialized
 475  * by \ref client_parse_config() before this function is called.
 476  *
 477  * \return Standard.
 478  */
 479 int client_connect(struct client_task *ct, struct sched *s,
 480                 struct btr_node *parent, struct btr_node *child)
 481 {
 482         int ret;
 483
 484         PARA_NOTICE_LOG("connecting %s:%d\n", ct->conf.hostname_arg,
 485                 ct->conf.server_port_arg);
 486         ct->scc.fd = -1;
 487         ret = para_connect_simple(IPPROTO_TCP, ct->conf.hostname_arg,
 488                                                ct->conf.server_port_arg);
 489         if (ret < 0)
 490                 return ret;
 491         ct->scc.fd = ret;
 492         ret = mark_fd_nonblocking(ct->scc.fd);
 493         if (ret < 0)
 494                 goto err_out;
 495         ct->status = CL_CONNECTED;
 496         ct->btrn = btr_new_node(&(struct btr_node_description)
 497                 EMBRACE(.name = "client", .parent = parent, .child = child));
 498         ct->task.pre_select = client_pre_select;
 499         ct->task.post_select = client_post_select;
 500         ct->task.error = 0;
 501         sprintf(ct->task.status, "client");
 502         register_task(s, &ct->task);
 503         return 1;
 504 err_out:
 505         close(ct->scc.fd);
 506         ct->scc.fd = -1;
 507         return ret;
 508 }
 509
 510 /**
 511  * Parse a client configuration.
 512  *
 513  * \param argc Usual argument count.
 514  * \param argv Usual argument vector.
 515  * \param ct_ptr Filled in by this function.
 516  * \param loglevel If not \p NULL, the number of the loglevel is stored here.
 517  *
 518  * This checks the command line options given by \a argc and \a argv, sets
 519  * default values for the user name and the name of the rsa key file and reads
 520  * further options from the config file.
 521  *
 522  * Upon successful return, \a ct_ptr points to a dynamically allocated and
 523  * initialized client task struct.
 524  *
 525  * \return The number of non-option arguments in \a argc/argv on success,
 526  * negative on errors.
 527  */
 528 int client_parse_config(int argc, char *argv[], struct client_task **ct_ptr,
 529                 int *loglevel)
 530 {
 531         char *home = para_homedir();
 532         int ret;
 533         struct client_task *ct = para_calloc(sizeof(struct client_task));
 534
 535         *ct_ptr = ct;
 536         ct->scc.fd = -1;
 537         ret = -E_CLIENT_SYNTAX;
 538         if (client_cmdline_parser(argc, argv, &ct->conf))
 539                 goto out;
 540         HANDLE_VERSION_FLAG("client", ct->conf);
 541
 542         ct->config_file = ct->conf.config_file_given?
 543                 para_strdup(ct->conf.config_file_arg) :
 544                 make_message("%s/.paraslash/client.conf", home);
 545         ret = file_exists(ct->config_file);
 546         if (!ret && ct->conf.config_file_given) {
 547                 ret = -E_NO_CONFIG;
 548                 goto out;
 549         }
 550         if (ret) {
 551                 struct client_cmdline_parser_params params = {
 552                         .override = 0,
 553                         .initialize = 0,
 554                         .check_required = 0,
 555                         .check_ambiguity = 0,
 556                         .print_errors = 0
 557                 };
 558                 ret = -E_BAD_CONFIG;
 559                 if (client_cmdline_parser_config_file(ct->config_file,
 560                         &ct->conf, &params))
 561                         goto out;
 562         }
 563         ct->user = ct->conf.user_given?
 564                 para_strdup(ct->conf.user_arg) : para_logname();
 565
 566         if (ct->conf.key_file_given)
 567                 ct->key_file = para_strdup(ct->conf.key_file_arg);
 568         else {
 569                 ct->key_file = make_message("%s/.paraslash/key.%s",
 570                         home, ct->user);
 571                 if (!file_exists(ct->key_file)) {
 572                         free(ct->key_file);
 573                         ct->key_file = make_message("%s/.ssh/id_rsa", home);
 574                 }
 575         }
 576
 577         if (loglevel)
 578                 *loglevel = get_loglevel_by_name(ct->conf.loglevel_arg);
 579         PARA_INFO_LOG("loglevel: %s\n", ct->conf.loglevel_arg);
 580         PARA_INFO_LOG("config_file: %s\n", ct->config_file);
 581         PARA_INFO_LOG("key_file: %s\n", ct->key_file);
 582         ret = ct->conf.inputs_num;
 583 out:
 584         free(home);
 585         if (ret < 0) {
 586                 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
 587                 client_close(ct);
 588                 *ct_ptr = NULL;
 589         }
 590         return ret;
 591 }
 592
 593 /**
 594  * Parse the client configuration and open a connection to para_server.
 595  *
 596  * \param argc See \ref client_parse_config.
 597  * \param argv See \ref client_parse_config.
 598  * \param ct_ptr See \ref client_parse_config.
 599  * \param loglevel See \ref client_parse_config.
 600  * \param parent See \ref client_connect().
 601  * \param child See \ref client_connect().
 602  * \param sched See \ref client_connect().
 603  *
 604  * This function combines client_parse_config() and client_connect(). It is
 605  * considered a syntax error if no command was given, i.e. if the number
 606  * of non-option arguments is zero.
 607  *
 608  * \return Standard.
 609  */
 610 int client_open(int argc, char *argv[], struct client_task **ct_ptr,
 611                 int *loglevel, struct btr_node *parent, struct btr_node *child,
 612                 struct sched *sched)
 613 {
 614         int ret = client_parse_config(argc, argv, ct_ptr, loglevel);
 615
 616         if (ret < 0)
 617                 return ret;
 618         if (ret == 0) {
 619                 ret = -E_CLIENT_SYNTAX;
 620                 goto fail;
 621         }
 622         ret = client_connect(*ct_ptr, sched, parent, child);
 623         if (ret < 0)
 624                 goto fail;
 625         return 1;
 626 fail:
 627         client_close(*ct_ptr);
 628         *ct_ptr = NULL;
 629         return ret;
 630 }