client_common.c

   1 /*
   2  * Copyright (C) 1997-2012 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         sc_free(ct->scc.recv);
  48         ct->scc.recv = NULL;
  49         sc_free(ct->scc.send);
  50         ct->scc.send = NULL;
  51         btr_free_node(ct->btrn);
  52         ct->btrn = NULL;
  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 bool has_feature(const char *feature, struct client_task *ct)
 244 {
 245         return find_arg(feature, ct->features) >= 0? true : false;
 246 }
 247
 248 /**
 249  * The post select hook for client commands.
 250  *
 251  * \param s Pointer to the scheduler.
 252  * \param t Pointer to the task struct for this command.
 253  *
 254  * Depending on the current state of the connection and the status of the read
 255  * and write fd sets of \a s, this function performs the necessary steps to
 256  * authenticate the connection, to send the command given by \a t->private_data
 257  * and to receive para_server's output, if any.
 258  *
 259  * \sa struct sched, struct task.
 260  */
 261 static void client_post_select(struct sched *s, struct task *t)
 262 {
 263         struct client_task *ct = container_of(t, struct client_task, task);
 264         struct btr_node *btrn = ct->btrn;
 265         int ret = 0;
 266         size_t n;
 267         char buf[CLIENT_BUFSIZE];
 268
 269         t->error = 0;
 270         if (ct->scc.fd < 0)
 271                 return;
 272         switch (ct->status) {
 273         case CL_CONNECTED: /* receive welcome message */
 274                 ret = client_recv_buffer(ct, &s->rfds, buf, sizeof(buf), &n);
 275                 if (ret < 0 || n == 0)
 276                         goto out;
 277                 ct->features = parse_features(buf);
 278                 ct->status = CL_RECEIVED_WELCOME;
 279                 return;
 280         case CL_RECEIVED_WELCOME: /* send auth command */
 281                 if (!FD_ISSET(ct->scc.fd, &s->wfds))
 282                         return;
 283                 if (has_feature("sideband", ct)) {
 284                         ct->use_sideband = true;
 285                         sprintf(buf, AUTH_REQUEST_MSG "%s sideband", ct->user);
 286                 } else
 287                         sprintf(buf, AUTH_REQUEST_MSG "%s", ct->user);
 288                 PARA_INFO_LOG("--> %s\n", buf);
 289                 ret = write_buffer(ct->scc.fd, buf);
 290                 if (ret < 0)
 291                         goto out;
 292                 ct->status = CL_SENT_AUTH;
 293                 return;
 294         case CL_SENT_AUTH:
 295                 /*
 296                  * Receive challenge and session keys, decrypt the challenge and
 297                  * send back the hash of the decrypted challenge.
 298                  */
 299                 {
 300                 /* decrypted challenge/session key buffer */
 301                 unsigned char crypt_buf[1024];
 302                 /* the SHA1 of the decrypted challenge */
 303
 304                 if (ct->use_sideband) {
 305                         struct sb_buffer sbb;
 306                         ret = recv_sb(ct, &s->rfds, &sbb);
 307                         if (ret <= 0)
 308                                 goto out;
 309                         if (sbb.band != SBD_CHALLENGE) {
 310                                 ret = -E_BAD_BAND;
 311                                 free(sbb.iov.iov_base);
 312                                         goto out;
 313                         }
 314                         n = sbb.iov.iov_len;
 315                         PARA_INFO_LOG("<-- [challenge] (%zu bytes)\n", n);
 316                         ret = priv_decrypt(ct->key_file, crypt_buf,
 317                                 sbb.iov.iov_base, n);
 318                         free(sbb.iov.iov_base);
 319                         if (ret < 0)
 320                                 goto out;
 321                 } else {
 322                         ret = client_recv_buffer(ct, &s->rfds, buf, sizeof(buf), &n);
 323                         if (ret < 0 || n == 0)
 324                                 goto out;
 325                         PARA_INFO_LOG("<-- [challenge] (%zu bytes)\n", n);
 326                         ret = priv_decrypt(ct->key_file, crypt_buf,
 327                                 (unsigned char *)buf, n);
 328                         if (ret < 0)
 329                                 goto out;
 330                 }
 331                 ct->challenge_hash = para_malloc(HASH_SIZE);
 332                 hash_function((char *)crypt_buf, CHALLENGE_SIZE, ct->challenge_hash);
 333                 ct->scc.send = sc_new(crypt_buf + CHALLENGE_SIZE, SESSION_KEY_LEN);
 334                 ct->scc.recv = sc_new(crypt_buf + CHALLENGE_SIZE + SESSION_KEY_LEN,
 335                         SESSION_KEY_LEN);
 336                 hash_to_asc(ct->challenge_hash, buf);
 337                 PARA_INFO_LOG("--> %s\n", buf);
 338                 ct->status = CL_RECEIVED_CHALLENGE;
 339                 return;
 340                 }
 341         case CL_RECEIVED_CHALLENGE:
 342                 if (ct->use_sideband) {
 343                         ret = send_sb(ct, ct->challenge_hash, HASH_SIZE,
 344                                 SBD_CHALLENGE_RESPONSE, false);
 345                         if (ret != 0)
 346                                 ct->challenge_hash = NULL;
 347                         if (ret <= 0)
 348                                 goto out;
 349                 } else {
 350                         ret = write_all(ct->scc.fd, (char *)ct->challenge_hash, HASH_SIZE);
 351                         if (ret < 0)
 352                                 goto out;
 353                 }
 354                 ct->status = CL_SENT_CH_RESPONSE;
 355                 goto out;
 356         case CL_SENT_CH_RESPONSE: /* read server response */
 357                 {
 358                 if (ct->use_sideband) {
 359                         struct sb_buffer sbb;
 360                         ret = recv_sb(ct, &s->rfds, &sbb);
 361                         if (ret <= 0)
 362                                 goto out;
 363                         free(sbb.iov.iov_base);
 364                         if (sbb.band != SBD_PROCEED)
 365                                 ret = -E_BAD_BAND;
 366                         else
 367                                 ct->status = CL_RECEIVED_PROCEED;
 368                         goto out;
 369                 }
 370                 ret = client_recv_buffer(ct, &s->rfds, buf, sizeof(buf), &n);
 371                 if (ret < 0 || n == 0)
 372                         goto out;
 373                 /* check if server has sent "Proceed" message */
 374                 ret = -E_CLIENT_AUTH;
 375                 if (n < PROCEED_MSG_LEN)
 376                         goto out;
 377                 if (!strstr(buf, PROCEED_MSG))
 378                         goto out;
 379                 ct->status = CL_RECEIVED_PROCEED;
 380                 return;
 381                 }
 382         case CL_RECEIVED_PROCEED: /* concat args and send command */
 383                 {
 384                 int i;
 385                 char *command = NULL;
 386                 if (!FD_ISSET(ct->scc.fd, &s->wfds))
 387                         return;
 388                 for (i = 0; i < ct->conf.inputs_num; i++) {
 389                         char *tmp = command;
 390                         command = make_message("%s\n%s", command?
 391                                 command : "", ct->conf.inputs[i]);
 392                         free(tmp);
 393                 }
 394                 command = para_strcat(command, EOC_MSG "\n");
 395                 PARA_DEBUG_LOG("--> %s\n", command);
 396                 ret = sc_send_buffer(&ct->scc, command);
 397                 free(command);
 398                 if (ret < 0)
 399                         goto out;
 400                 ct->status = CL_SENT_COMMAND;
 401                 return;
 402                 }
 403         case CL_SENT_COMMAND:
 404                 {
 405                 char *buf2;
 406                 /* can not use "buf" here because we need a malloced buffer */
 407                 buf2 = para_malloc(CLIENT_BUFSIZE);
 408                 ret = client_recv_buffer(ct, &s->rfds, buf2, CLIENT_BUFSIZE, &n);
 409                 if (n > 0) {
 410                         if (strstr(buf2, AWAITING_DATA_MSG)) {
 411                                 free(buf2);
 412                                 ct->status = CL_SENDING;
 413                                 return;
 414                         }
 415                         ct->status = CL_RECEIVING;
 416                         btr_add_output(buf2, n, btrn);
 417                 } else
 418                         free(buf2);
 419                 goto out;
 420                 }
 421         case CL_SENDING:
 422                 {
 423                 char *buf2;
 424                 size_t sz;
 425                 ret = btr_node_status(btrn, 0, BTR_NT_LEAF);
 426                 if (ret < 0)
 427                         goto out;
 428                 if (ret == 0)
 429                         return;
 430                 if (!FD_ISSET(ct->scc.fd, &s->wfds))
 431                         return;
 432                 sz = btr_next_buffer(btrn, &buf2);
 433                 ret = sc_send_bin_buffer(&ct->scc, buf2, sz);
 434                 if (ret < 0)
 435                         goto out;
 436                 btr_consume(btrn, sz);
 437                 return;
 438                 }
 439         case CL_RECEIVING:
 440                 {
 441                 char *buf2;
 442                 ret = btr_node_status(btrn, 0, BTR_NT_ROOT);
 443                 if (ret < 0)
 444                         goto out;
 445                 if (ret == 0)
 446                         return;
 447                 /*
 448                  * The FD_ISSET() is not strictly necessary, but is allows us
 449                  * to skip the malloc below if there is nothing to read anyway.
 450                  */
 451                 if (!FD_ISSET(ct->scc.fd, &s->rfds))
 452                         return;
 453                 buf2 = para_malloc(CLIENT_BUFSIZE);
 454                 ret = client_recv_buffer(ct, &s->rfds, buf2, CLIENT_BUFSIZE, &n);
 455                 if (n > 0) {
 456                         buf2 = para_realloc(buf2, n);
 457                         btr_add_output(buf2, n, btrn);
 458                 } else
 459                         free(buf2);
 460                 goto out;
 461                 }
 462         }
 463 out:
 464         t->error = ret;
 465         if (ret < 0) {
 466                 if (ret != -E_SERVER_EOF && ret != -E_BTR_EOF && ret != -E_EOF)
 467                         PARA_ERROR_LOG("%s\n", para_strerror(-t->error));
 468                 btr_remove_node(btrn);
 469         }
 470 }
 471
 472 /**
 473  * Connect to para_server and register the client task.
 474  *
 475  * \param ct The initialized client task structure.
 476  * \param s The scheduler instance to register the client task to.
 477  * \param parent The parent node of the client btr node.
 478  * \param child The child node of the client node.
 479  *
 480  * The client task structure given by \a ct  must be allocated and initialized
 481  * by \ref client_parse_config() before this function is called.
 482  *
 483  * \return Standard.
 484  */
 485 int client_connect(struct client_task *ct, struct sched *s,
 486                 struct btr_node *parent, struct btr_node *child)
 487 {
 488         int ret;
 489
 490         PARA_NOTICE_LOG("connecting %s:%d\n", ct->conf.hostname_arg,
 491                 ct->conf.server_port_arg);
 492         ct->scc.fd = -1;
 493         ret = para_connect_simple(IPPROTO_TCP, ct->conf.hostname_arg,
 494                                                ct->conf.server_port_arg);
 495         if (ret < 0)
 496                 return ret;
 497         ct->scc.fd = ret;
 498         ret = mark_fd_nonblocking(ct->scc.fd);
 499         if (ret < 0)
 500                 goto err_out;
 501         ct->status = CL_CONNECTED;
 502         ct->btrn = btr_new_node(&(struct btr_node_description)
 503                 EMBRACE(.name = "client", .parent = parent, .child = child));
 504         ct->task.pre_select = client_pre_select;
 505         ct->task.post_select = client_post_select;
 506         ct->task.error = 0;
 507         sprintf(ct->task.status, "client");
 508         register_task(s, &ct->task);
 509         return 1;
 510 err_out:
 511         close(ct->scc.fd);
 512         ct->scc.fd = -1;
 513         return ret;
 514 }
 515
 516 /**
 517  * Parse a client configuration.
 518  *
 519  * \param argc Usual argument count.
 520  * \param argv Usual argument vector.
 521  * \param ct_ptr Filled in by this function.
 522  * \param loglevel If not \p NULL, the number of the loglevel is stored here.
 523  *
 524  * This checks the command line options given by \a argc and \a argv, sets
 525  * default values for the user name and the name of the rsa key file and reads
 526  * further options from the config file.
 527  *
 528  * Upon successful return, \a ct_ptr points to a dynamically allocated and
 529  * initialized client task struct.
 530  *
 531  * \return The number of non-option arguments in \a argc/argv on success,
 532  * negative on errors.
 533  */
 534 int client_parse_config(int argc, char *argv[], struct client_task **ct_ptr,
 535                 int *loglevel)
 536 {
 537         char *home = para_homedir();
 538         int ret;
 539         struct client_task *ct = para_calloc(sizeof(struct client_task));
 540
 541         *ct_ptr = ct;
 542         ct->scc.fd = -1;
 543         ret = -E_CLIENT_SYNTAX;
 544         if (client_cmdline_parser(argc, argv, &ct->conf))
 545                 goto out;
 546         HANDLE_VERSION_FLAG("client", ct->conf);
 547
 548         ct->config_file = ct->conf.config_file_given?
 549                 para_strdup(ct->conf.config_file_arg) :
 550                 make_message("%s/.paraslash/client.conf", home);
 551         ret = file_exists(ct->config_file);
 552         if (!ret && ct->conf.config_file_given) {
 553                 ret = -E_NO_CONFIG;
 554                 goto out;
 555         }
 556         if (ret) {
 557                 struct client_cmdline_parser_params params = {
 558                         .override = 0,
 559                         .initialize = 0,
 560                         .check_required = 0,
 561                         .check_ambiguity = 0,
 562                         .print_errors = 0
 563                 };
 564                 ret = -E_BAD_CONFIG;
 565                 if (client_cmdline_parser_config_file(ct->config_file,
 566                         &ct->conf, &params))
 567                         goto out;
 568         }
 569         ct->user = ct->conf.user_given?
 570                 para_strdup(ct->conf.user_arg) : para_logname();
 571
 572         if (ct->conf.key_file_given)
 573                 ct->key_file = para_strdup(ct->conf.key_file_arg);
 574         else {
 575                 ct->key_file = make_message("%s/.paraslash/key.%s",
 576                         home, ct->user);
 577                 if (!file_exists(ct->key_file)) {
 578                         free(ct->key_file);
 579                         ct->key_file = make_message("%s/.ssh/id_rsa", home);
 580                 }
 581         }
 582
 583         if (loglevel)
 584                 *loglevel = get_loglevel_by_name(ct->conf.loglevel_arg);
 585         PARA_INFO_LOG("loglevel: %s\n", ct->conf.loglevel_arg);
 586         PARA_INFO_LOG("config_file: %s\n", ct->config_file);
 587         PARA_INFO_LOG("key_file: %s\n", ct->key_file);
 588         ret = ct->conf.inputs_num;
 589 out:
 590         free(home);
 591         if (ret < 0) {
 592                 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
 593                 client_close(ct);
 594                 *ct_ptr = NULL;
 595         }
 596         return ret;
 597 }
 598
 599 /**
 600  * Parse the client configuration and open a connection to para_server.
 601  *
 602  * \param argc See \ref client_parse_config.
 603  * \param argv See \ref client_parse_config.
 604  * \param ct_ptr See \ref client_parse_config.
 605  * \param loglevel See \ref client_parse_config.
 606  * \param parent See \ref client_connect().
 607  * \param child See \ref client_connect().
 608  * \param sched See \ref client_connect().
 609  *
 610  * This function combines client_parse_config() and client_connect(). It is
 611  * considered a syntax error if no command was given, i.e. if the number
 612  * of non-option arguments is zero.
 613  *
 614  * \return Standard.
 615  */
 616 int client_open(int argc, char *argv[], struct client_task **ct_ptr,
 617                 int *loglevel, struct btr_node *parent, struct btr_node *child,
 618                 struct sched *sched)
 619 {
 620         int ret = client_parse_config(argc, argv, ct_ptr, loglevel);
 621
 622         if (ret < 0)
 623                 return ret;
 624         if (ret == 0) {
 625                 ret = -E_CLIENT_SYNTAX;
 626                 goto fail;
 627         }
 628         ret = client_connect(*ct_ptr, sched, parent, child);
 629         if (ret < 0)
 630                 goto fail;
 631         return 1;
 632 fail:
 633         client_close(*ct_ptr);
 634         *ct_ptr = NULL;
 635         return ret;
 636 }