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);
  72 }
  73
  74 /**
  75  * The preselect hook for server commands.
  76  *
  77  * \param s Pointer to the scheduler.
  78  * \param t Pointer to the task struct for this command.
  79  *
  80  * The task pointer must contain a pointer to the initialized client data
  81  * structure as it is returned by client_open().
  82  *
  83  * This function checks the state of the connection and adds the file descriptor
  84  * of the connection to the read or write fd set of \a s accordingly.
  85  *
  86  * \sa register_task() client_open(), struct sched, struct task.
  87  */
  88 static void client_pre_select(struct sched *s, struct task *t)
  89 {
  90         int ret;
  91         struct client_task *ct = container_of(t, struct client_task, task);
  92         struct btr_node *btrn = ct->btrn;
  93
  94         if (ct->scc.fd < 0)
  95                 return;
  96         switch (ct->status) {
  97         case CL_CONNECTED:
  98         case CL_SENT_AUTH:
  99         case CL_SENT_CH_RESPONSE:
 100         case CL_SENT_COMMAND:
 101                 para_fd_set(ct->scc.fd, &s->rfds, &s->max_fileno);
 102                 return;
 103
 104         case CL_RECEIVED_WELCOME:
 105         case CL_RECEIVED_PROCEED:
 106                 para_fd_set(ct->scc.fd, &s->wfds, &s->max_fileno);
 107                 return;
 108
 109         case CL_RECEIVING:
 110                 ret = btr_node_status(btrn, 0, BTR_NT_ROOT);
 111                 if (ret != 0) {
 112                         if (ret < 0)
 113                                 sched_min_delay(s);
 114                         else
 115                                 para_fd_set(ct->scc.fd, &s->rfds,
 116                                         &s->max_fileno);
 117                 }
 118                 return;
 119         case CL_SENDING:
 120                 ret = btr_node_status(btrn, 0, BTR_NT_LEAF);
 121                 if (ret != 0) {
 122                         if (ret < 0)
 123                                 sched_min_delay(s);
 124                         else
 125                                 para_fd_set(ct->scc.fd, &s->wfds,
 126                                         &s->max_fileno);
 127                 }
 128                 return;
 129         }
 130 }
 131
 132 static int client_recv_buffer(struct client_task *ct, fd_set *rfds,
 133                 char *buf, size_t sz, size_t *n)
 134 {
 135         int ret;
 136
 137         if (ct->status < CL_SENT_CH_RESPONSE)
 138                 return read_nonblock(ct->scc.fd, buf, sz, rfds, n);
 139
 140         *n = 0;
 141         ret = sc_recv_buffer(&ct->scc, buf, sz);
 142         /*
 143          * sc_recv_buffer is used with blocking fds elsewhere, so it
 144          * does not use the nonblock-API. Therefore we need to
 145          * check for EOF and EAGAIN.
 146          */
 147         if (ret == 0)
 148                 return -E_SERVER_EOF;
 149         if (ret == -ERRNO_TO_PARA_ERROR(EAGAIN))
 150                 return 0;
 151         if (ret < 0)
 152                 return ret;
 153         *n = ret;
 154         return 0;
 155 }
 156
 157 static int send_sb(struct client_task *ct, void *buf, size_t numbytes,
 158                 enum sb_designator band, bool dont_free)
 159 {
 160         int ret, fd = ct->scc.fd;
 161         struct iovec iov[2];
 162
 163         if (!ct->sbc) {
 164                 struct sb_buffer sbb;
 165                 sb_transformation trafo = ct->status < CL_RECEIVED_PROCEED?
 166                         NULL : sc_trafo;
 167                 sbb = (typeof(sbb))SBB_INIT(band, buf, numbytes);
 168                 ct->sbc = sb_new_send(&sbb, dont_free, trafo, ct->scc.send);
 169         }
 170         ret = sb_get_send_buffers(ct->sbc, iov);
 171         ret = xwritev(fd, iov, ret);
 172         if (ret < 0) {
 173                 sb_free(ct->sbc);
 174                 ct->sbc = NULL;
 175                 return ret;
 176         }
 177         if (sb_sent(ct->sbc, ret)) {
 178                 ct->sbc = NULL;
 179                 return 1;
 180         }
 181         return 0;
 182 }
 183
 184 static int recv_sb(struct client_task *ct, fd_set *rfds,
 185                 struct sb_buffer *result)
 186 {
 187         int ret;
 188         size_t n;
 189         sb_transformation trafo;
 190         void *trafo_context;
 191         struct iovec iov;
 192
 193         if (!FD_ISSET(ct->scc.fd, rfds))
 194                 return 0;
 195         if (ct->status < CL_SENT_CH_RESPONSE)
 196                 trafo = trafo_context = NULL;
 197         else {
 198                 trafo = sc_trafo;
 199                 trafo_context = ct->scc.recv;
 200         }
 201         if (!ct->sbc)
 202                 ct->sbc = sb_new_recv(0, trafo, trafo_context);
 203 again:
 204         sb_get_recv_buffer(ct->sbc, &iov);
 205         ret = read_nonblock(ct->scc.fd, iov.iov_base, iov.iov_len, rfds, &n);
 206         if (ret < 0) {
 207                 sb_free(ct->sbc);
 208                 ct->sbc = NULL;
 209                 return ret;
 210         }
 211         if (n == 0)
 212                 return 0;
 213         if (!sb_received(ct->sbc, n, result))
 214                 goto again;
 215         ct->sbc = NULL;
 216         return 1;
 217 }
 218
 219
 220 static char **parse_features(char *buf)
 221 {
 222         int i;
 223         const char id[] = "\nFeatures: ";
 224         char *p, *q, **features;
 225
 226         p = strstr(buf, id);
 227         if (!p)
 228                 return NULL;
 229         p += strlen(id);
 230         q = strchr(p, '\n');
 231         if (!q)
 232                 return NULL;
 233         *q = '\0';
 234         create_argv(p, ",", &features);
 235         for (i = 0; features[i]; i++)
 236                 PARA_INFO_LOG("server feature: %s\n", features[i]);
 237         return features;
 238 }
 239
 240 static bool has_feature(const char *feature, struct client_task *ct)
 241 {
 242         return find_arg(feature, ct->features) >= 0? true : false;
 243 }
 244
 245 /**
 246  * The post select hook for client commands.
 247  *
 248  * \param s Pointer to the scheduler.
 249  * \param t Pointer to the task struct for this command.
 250  *
 251  * Depending on the current state of the connection and the status of the read
 252  * and write fd sets of \a s, this function performs the necessary steps to
 253  * authenticate the connection, to send the command given by \a t->private_data
 254  * and to receive para_server's output, if any.
 255  *
 256  * \sa struct sched, struct task.
 257  */
 258 static void client_post_select(struct sched *s, struct task *t)
 259 {
 260         struct client_task *ct = container_of(t, struct client_task, task);
 261         struct btr_node *btrn = ct->btrn;
 262         int ret = 0;
 263         size_t n;
 264         char buf[CLIENT_BUFSIZE];
 265
 266         t->error = 0;
 267         if (ct->scc.fd < 0)
 268                 return;
 269         switch (ct->status) {
 270         case CL_CONNECTED: /* receive welcome message */
 271                 ret = client_recv_buffer(ct, &s->rfds, buf, sizeof(buf), &n);
 272                 if (ret < 0 || n == 0)
 273                         goto out;
 274                 ct->features = parse_features(buf);
 275                 ct->status = CL_RECEIVED_WELCOME;
 276                 return;
 277         case CL_RECEIVED_WELCOME: /* send auth command */
 278                 if (!FD_ISSET(ct->scc.fd, &s->wfds))
 279                         return;
 280                 if (has_feature("sideband", ct)) {
 281                         ct->use_sideband = true;
 282                         sprintf(buf, AUTH_REQUEST_MSG "%s sideband", ct->user);
 283                 } else
 284                         sprintf(buf, AUTH_REQUEST_MSG "%s", ct->user);
 285                 PARA_INFO_LOG("--> %s\n", buf);
 286                 ret = write_buffer(ct->scc.fd, buf);
 287                 if (ret < 0)
 288                         goto out;
 289                 ct->status = CL_SENT_AUTH;
 290                 return;
 291         case CL_SENT_AUTH:
 292                 /*
 293                  * Receive challenge and session keys, decrypt the challenge and
 294                  * send back the hash of the decrypted challenge.
 295                  */
 296                 {
 297                 /* decrypted challenge/session key buffer */
 298                 unsigned char crypt_buf[1024];
 299                 /* the SHA1 of the decrypted challenge */
 300                 unsigned char challenge_hash[HASH_SIZE];
 301
 302                 if (ct->use_sideband) {
 303                         struct sb_buffer sbb;
 304                         ret = recv_sb(ct, &s->rfds, &sbb);
 305                         if (ret <= 0)
 306                                 goto out;
 307                         if (sbb.band != SBD_CHALLENGE) {
 308                                 ret = -E_BAD_BAND;
 309                                 free(sbb.iov.iov_base);
 310                                         goto out;
 311                         }
 312                         n = sbb.iov.iov_len;
 313                         PARA_INFO_LOG("<-- [challenge] (%zu bytes)\n", n);
 314                         ret = priv_decrypt(ct->key_file, crypt_buf,
 315                                 sbb.iov.iov_base, n);
 316                         free(sbb.iov.iov_base);
 317                         if (ret < 0)
 318                                 goto out;
 319                 } else {
 320                         ret = client_recv_buffer(ct, &s->rfds, buf, sizeof(buf), &n);
 321                         if (ret < 0 || n == 0)
 322                                 goto out;
 323                         PARA_INFO_LOG("<-- [challenge] (%zu bytes)\n", n);
 324                         ret = priv_decrypt(ct->key_file, crypt_buf,
 325                                 (unsigned char *)buf, n);
 326                         if (ret < 0)
 327                                 goto out;
 328                 }
 329                 hash_function((char *)crypt_buf, CHALLENGE_SIZE, challenge_hash);
 330                 ct->scc.send = sc_new(crypt_buf + CHALLENGE_SIZE, SESSION_KEY_LEN);
 331                 ct->scc.recv = sc_new(crypt_buf + CHALLENGE_SIZE + SESSION_KEY_LEN,
 332                         SESSION_KEY_LEN);
 333                 hash_to_asc(challenge_hash, buf);
 334                 PARA_INFO_LOG("--> %s\n", buf);
 335                 ret = write_all(ct->scc.fd, (char *)challenge_hash, HASH_SIZE);
 336                 if (ret < 0)
 337                         goto out;
 338                 ct->status = CL_SENT_CH_RESPONSE;
 339                 return;
 340                 }
 341         case CL_SENT_CH_RESPONSE: /* read server response */
 342                 {
 343                 ret = client_recv_buffer(ct, &s->rfds, buf, sizeof(buf), &n);
 344                 if (ret < 0 || n == 0)
 345                         goto out;
 346                 /* check if server has sent "Proceed" message */
 347                 ret = -E_CLIENT_AUTH;
 348                 if (n < PROCEED_MSG_LEN)
 349                         goto out;
 350                 if (!strstr(buf, PROCEED_MSG))
 351                         goto out;
 352                 ct->status = CL_RECEIVED_PROCEED;
 353                 return;
 354                 }
 355         case CL_RECEIVED_PROCEED: /* concat args and send command */
 356                 {
 357                 int i;
 358                 char *command = NULL;
 359                 if (!FD_ISSET(ct->scc.fd, &s->wfds))
 360                         return;
 361                 for (i = 0; i < ct->conf.inputs_num; i++) {
 362                         char *tmp = command;
 363                         command = make_message("%s\n%s", command?
 364                                 command : "", ct->conf.inputs[i]);
 365                         free(tmp);
 366                 }
 367                 command = para_strcat(command, EOC_MSG "\n");
 368                 PARA_DEBUG_LOG("--> %s\n", command);
 369                 ret = sc_send_buffer(&ct->scc, command);
 370                 free(command);
 371                 if (ret < 0)
 372                         goto out;
 373                 ct->status = CL_SENT_COMMAND;
 374                 return;
 375                 }
 376         case CL_SENT_COMMAND:
 377                 {
 378                 char *buf2;
 379                 /* can not use "buf" here because we need a malloced buffer */
 380                 buf2 = para_malloc(CLIENT_BUFSIZE);
 381                 ret = client_recv_buffer(ct, &s->rfds, buf2, CLIENT_BUFSIZE, &n);
 382                 if (n > 0) {
 383                         if (strstr(buf2, AWAITING_DATA_MSG)) {
 384                                 free(buf2);
 385                                 ct->status = CL_SENDING;
 386                                 return;
 387                         }
 388                         ct->status = CL_RECEIVING;
 389                         btr_add_output(buf2, n, btrn);
 390                 } else
 391                         free(buf2);
 392                 goto out;
 393                 }
 394         case CL_SENDING:
 395                 {
 396                 char *buf2;
 397                 size_t sz;
 398                 ret = btr_node_status(btrn, 0, BTR_NT_LEAF);
 399                 if (ret < 0)
 400                         goto out;
 401                 if (ret == 0)
 402                         return;
 403                 if (!FD_ISSET(ct->scc.fd, &s->wfds))
 404                         return;
 405                 sz = btr_next_buffer(btrn, &buf2);
 406                 ret = sc_send_bin_buffer(&ct->scc, buf2, sz);
 407                 if (ret < 0)
 408                         goto out;
 409                 btr_consume(btrn, sz);
 410                 return;
 411                 }
 412         case CL_RECEIVING:
 413                 {
 414                 char *buf2;
 415                 ret = btr_node_status(btrn, 0, BTR_NT_ROOT);
 416                 if (ret < 0)
 417                         goto out;
 418                 if (ret == 0)
 419                         return;
 420                 /*
 421                  * The FD_ISSET() is not strictly necessary, but is allows us
 422                  * to skip the malloc below if there is nothing to read anyway.
 423                  */
 424                 if (!FD_ISSET(ct->scc.fd, &s->rfds))
 425                         return;
 426                 buf2 = para_malloc(CLIENT_BUFSIZE);
 427                 ret = client_recv_buffer(ct, &s->rfds, buf2, CLIENT_BUFSIZE, &n);
 428                 if (n > 0) {
 429                         buf2 = para_realloc(buf2, n);
 430                         btr_add_output(buf2, n, btrn);
 431                 } else
 432                         free(buf2);
 433                 goto out;
 434                 }
 435         }
 436 out:
 437         t->error = ret;
 438         if (ret < 0) {
 439                 if (ret != -E_SERVER_EOF && ret != -E_BTR_EOF && ret != -E_EOF)
 440                         PARA_ERROR_LOG("%s\n", para_strerror(-t->error));
 441                 btr_remove_node(btrn);
 442         }
 443 }
 444
 445 /**
 446  * Connect to para_server and register the client task.
 447  *
 448  * \param ct The initialized client task structure.
 449  * \param s The scheduler instance to register the client task to.
 450  * \param parent The parent node of the client btr node.
 451  * \param child The child node of the client node.
 452  *
 453  * The client task structure given by \a ct  must be allocated and initialized
 454  * by \ref client_parse_config() before this function is called.
 455  *
 456  * \return Standard.
 457  */
 458 int client_connect(struct client_task *ct, struct sched *s,
 459                 struct btr_node *parent, struct btr_node *child)
 460 {
 461         int ret;
 462
 463         PARA_NOTICE_LOG("connecting %s:%d\n", ct->conf.hostname_arg,
 464                 ct->conf.server_port_arg);
 465         ct->scc.fd = -1;
 466         ret = para_connect_simple(IPPROTO_TCP, ct->conf.hostname_arg,
 467                                                ct->conf.server_port_arg);
 468         if (ret < 0)
 469                 return ret;
 470         ct->scc.fd = ret;
 471         ret = mark_fd_nonblocking(ct->scc.fd);
 472         if (ret < 0)
 473                 goto err_out;
 474         ct->status = CL_CONNECTED;
 475         ct->btrn = btr_new_node(&(struct btr_node_description)
 476                 EMBRACE(.name = "client", .parent = parent, .child = child));
 477         ct->task.pre_select = client_pre_select;
 478         ct->task.post_select = client_post_select;
 479         ct->task.error = 0;
 480         sprintf(ct->task.status, "client");
 481         register_task(s, &ct->task);
 482         return 1;
 483 err_out:
 484         close(ct->scc.fd);
 485         ct->scc.fd = -1;
 486         return ret;
 487 }
 488
 489 /**
 490  * Parse a client configuration.
 491  *
 492  * \param argc Usual argument count.
 493  * \param argv Usual argument vector.
 494  * \param ct_ptr Filled in by this function.
 495  * \param loglevel If not \p NULL, the number of the loglevel is stored here.
 496  *
 497  * This checks the command line options given by \a argc and \a argv, sets
 498  * default values for the user name and the name of the rsa key file and reads
 499  * further options from the config file.
 500  *
 501  * Upon successful return, \a ct_ptr points to a dynamically allocated and
 502  * initialized client task struct.
 503  *
 504  * \return The number of non-option arguments in \a argc/argv on success,
 505  * negative on errors.
 506  */
 507 int client_parse_config(int argc, char *argv[], struct client_task **ct_ptr,
 508                 int *loglevel)
 509 {
 510         char *home = para_homedir();
 511         int ret;
 512         struct client_task *ct = para_calloc(sizeof(struct client_task));
 513
 514         *ct_ptr = ct;
 515         ct->scc.fd = -1;
 516         ret = -E_CLIENT_SYNTAX;
 517         if (client_cmdline_parser(argc, argv, &ct->conf))
 518                 goto out;
 519         HANDLE_VERSION_FLAG("client", ct->conf);
 520
 521         ct->config_file = ct->conf.config_file_given?
 522                 para_strdup(ct->conf.config_file_arg) :
 523                 make_message("%s/.paraslash/client.conf", home);
 524         ret = file_exists(ct->config_file);
 525         if (!ret && ct->conf.config_file_given) {
 526                 ret = -E_NO_CONFIG;
 527                 goto out;
 528         }
 529         if (ret) {
 530                 struct client_cmdline_parser_params params = {
 531                         .override = 0,
 532                         .initialize = 0,
 533                         .check_required = 0,
 534                         .check_ambiguity = 0,
 535                         .print_errors = 0
 536                 };
 537                 ret = -E_BAD_CONFIG;
 538                 if (client_cmdline_parser_config_file(ct->config_file,
 539                         &ct->conf, &params))
 540                         goto out;
 541         }
 542         ct->user = ct->conf.user_given?
 543                 para_strdup(ct->conf.user_arg) : para_logname();
 544
 545         if (ct->conf.key_file_given)
 546                 ct->key_file = para_strdup(ct->conf.key_file_arg);
 547         else {
 548                 ct->key_file = make_message("%s/.paraslash/key.%s",
 549                         home, ct->user);
 550                 if (!file_exists(ct->key_file)) {
 551                         free(ct->key_file);
 552                         ct->key_file = make_message("%s/.ssh/id_rsa", home);
 553                 }
 554         }
 555
 556         if (loglevel)
 557                 *loglevel = get_loglevel_by_name(ct->conf.loglevel_arg);
 558         PARA_INFO_LOG("loglevel: %s\n", ct->conf.loglevel_arg);
 559         PARA_INFO_LOG("config_file: %s\n", ct->config_file);
 560         PARA_INFO_LOG("key_file: %s\n", ct->key_file);
 561         ret = ct->conf.inputs_num;
 562 out:
 563         free(home);
 564         if (ret < 0) {
 565                 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
 566                 client_close(ct);
 567                 *ct_ptr = NULL;
 568         }
 569         return ret;
 570 }
 571
 572 /**
 573  * Parse the client configuration and open a connection to para_server.
 574  *
 575  * \param argc See \ref client_parse_config.
 576  * \param argv See \ref client_parse_config.
 577  * \param ct_ptr See \ref client_parse_config.
 578  * \param loglevel See \ref client_parse_config.
 579  * \param parent See \ref client_connect().
 580  * \param child See \ref client_connect().
 581  * \param sched See \ref client_connect().
 582  *
 583  * This function combines client_parse_config() and client_connect(). It is
 584  * considered a syntax error if no command was given, i.e. if the number
 585  * of non-option arguments is zero.
 586  *
 587  * \return Standard.
 588  */
 589 int client_open(int argc, char *argv[], struct client_task **ct_ptr,
 590                 int *loglevel, struct btr_node *parent, struct btr_node *child,
 591                 struct sched *sched)
 592 {
 593         int ret = client_parse_config(argc, argv, ct_ptr, loglevel);
 594
 595         if (ret < 0)
 596                 return ret;
 597         if (ret == 0) {
 598                 ret = -E_CLIENT_SYNTAX;
 599                 goto fail;
 600         }
 601         ret = client_connect(*ct_ptr, sched, parent, child);
 602         if (ret < 0)
 603                 goto fail;
 604         return 1;
 605 fail:
 606         client_close(*ct_ptr);
 607         *ct_ptr = NULL;
 608         return ret;
 609 }