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                 ret = client_recv_buffer(ct, &s->rfds, buf, sizeof(buf), &n);
 303                 if (ret < 0 || n == 0)
 304                         goto out;
 305                 PARA_INFO_LOG("<-- [challenge] (%zu bytes)\n", n);
 306                 ret = priv_decrypt(ct->key_file, crypt_buf,
 307                         (unsigned char *)buf, n);
 308                 if (ret < 0)
 309                         goto out;
 310                 hash_function((char *)crypt_buf, CHALLENGE_SIZE, challenge_hash);
 311                 ct->scc.send = sc_new(crypt_buf + CHALLENGE_SIZE, SESSION_KEY_LEN);
 312                 ct->scc.recv = sc_new(crypt_buf + CHALLENGE_SIZE + SESSION_KEY_LEN,
 313                         SESSION_KEY_LEN);
 314                 hash_to_asc(challenge_hash, buf);
 315                 PARA_INFO_LOG("--> %s\n", buf);
 316                 ret = write_all(ct->scc.fd, (char *)challenge_hash, HASH_SIZE);
 317                 if (ret < 0)
 318                         goto out;
 319                 ct->status = CL_SENT_CH_RESPONSE;
 320                 return;
 321                 }
 322         case CL_SENT_CH_RESPONSE: /* read server response */
 323                 {
 324                 ret = client_recv_buffer(ct, &s->rfds, buf, sizeof(buf), &n);
 325                 if (ret < 0 || n == 0)
 326                         goto out;
 327                 /* check if server has sent "Proceed" message */
 328                 ret = -E_CLIENT_AUTH;
 329                 if (n < PROCEED_MSG_LEN)
 330                         goto out;
 331                 if (!strstr(buf, PROCEED_MSG))
 332                         goto out;
 333                 ct->status = CL_RECEIVED_PROCEED;
 334                 return;
 335                 }
 336         case CL_RECEIVED_PROCEED: /* concat args and send command */
 337                 {
 338                 int i;
 339                 char *command = NULL;
 340                 if (!FD_ISSET(ct->scc.fd, &s->wfds))
 341                         return;
 342                 for (i = 0; i < ct->conf.inputs_num; i++) {
 343                         char *tmp = command;
 344                         command = make_message("%s\n%s", command?
 345                                 command : "", ct->conf.inputs[i]);
 346                         free(tmp);
 347                 }
 348                 command = para_strcat(command, EOC_MSG "\n");
 349                 PARA_DEBUG_LOG("--> %s\n", command);
 350                 ret = sc_send_buffer(&ct->scc, command);
 351                 free(command);
 352                 if (ret < 0)
 353                         goto out;
 354                 ct->status = CL_SENT_COMMAND;
 355                 return;
 356                 }
 357         case CL_SENT_COMMAND:
 358                 {
 359                 char *buf2;
 360                 /* can not use "buf" here because we need a malloced buffer */
 361                 buf2 = para_malloc(CLIENT_BUFSIZE);
 362                 ret = client_recv_buffer(ct, &s->rfds, buf2, CLIENT_BUFSIZE, &n);
 363                 if (n > 0) {
 364                         if (strstr(buf2, AWAITING_DATA_MSG)) {
 365                                 free(buf2);
 366                                 ct->status = CL_SENDING;
 367                                 return;
 368                         }
 369                         ct->status = CL_RECEIVING;
 370                         btr_add_output(buf2, n, btrn);
 371                 } else
 372                         free(buf2);
 373                 goto out;
 374                 }
 375         case CL_SENDING:
 376                 {
 377                 char *buf2;
 378                 size_t sz;
 379                 ret = btr_node_status(btrn, 0, BTR_NT_LEAF);
 380                 if (ret < 0)
 381                         goto out;
 382                 if (ret == 0)
 383                         return;
 384                 if (!FD_ISSET(ct->scc.fd, &s->wfds))
 385                         return;
 386                 sz = btr_next_buffer(btrn, &buf2);
 387                 ret = sc_send_bin_buffer(&ct->scc, buf2, sz);
 388                 if (ret < 0)
 389                         goto out;
 390                 btr_consume(btrn, sz);
 391                 return;
 392                 }
 393         case CL_RECEIVING:
 394                 {
 395                 char *buf2;
 396                 ret = btr_node_status(btrn, 0, BTR_NT_ROOT);
 397                 if (ret < 0)
 398                         goto out;
 399                 if (ret == 0)
 400                         return;
 401                 /*
 402                  * The FD_ISSET() is not strictly necessary, but is allows us
 403                  * to skip the malloc below if there is nothing to read anyway.
 404                  */
 405                 if (!FD_ISSET(ct->scc.fd, &s->rfds))
 406                         return;
 407                 buf2 = para_malloc(CLIENT_BUFSIZE);
 408                 ret = client_recv_buffer(ct, &s->rfds, buf2, CLIENT_BUFSIZE, &n);
 409                 if (n > 0) {
 410                         buf2 = para_realloc(buf2, n);
 411                         btr_add_output(buf2, n, btrn);
 412                 } else
 413                         free(buf2);
 414                 goto out;
 415                 }
 416         }
 417 out:
 418         t->error = ret;
 419         if (ret < 0) {
 420                 if (ret != -E_SERVER_EOF && ret != -E_BTR_EOF)
 421                         PARA_ERROR_LOG("%s\n", para_strerror(-t->error));
 422                 btr_remove_node(btrn);
 423         }
 424 }
 425
 426 /**
 427  * Connect to para_server and register the client task.
 428  *
 429  * \param ct The initialized client task structure.
 430  * \param s The scheduler instance to register the client task to.
 431  * \param parent The parent node of the client btr node.
 432  * \param child The child node of the client node.
 433  *
 434  * The client task structure given by \a ct  must be allocated and initialized
 435  * by \ref client_parse_config() before this function is called.
 436  *
 437  * \return Standard.
 438  */
 439 int client_connect(struct client_task *ct, struct sched *s,
 440                 struct btr_node *parent, struct btr_node *child)
 441 {
 442         int ret;
 443
 444         PARA_NOTICE_LOG("connecting %s:%d\n", ct->conf.hostname_arg,
 445                 ct->conf.server_port_arg);
 446         ct->scc.fd = -1;
 447         ret = para_connect_simple(IPPROTO_TCP, ct->conf.hostname_arg,
 448                                                ct->conf.server_port_arg);
 449         if (ret < 0)
 450                 return ret;
 451         ct->scc.fd = ret;
 452         ret = mark_fd_nonblocking(ct->scc.fd);
 453         if (ret < 0)
 454                 goto err_out;
 455         ct->status = CL_CONNECTED;
 456         ct->btrn = btr_new_node(&(struct btr_node_description)
 457                 EMBRACE(.name = "client", .parent = parent, .child = child));
 458         ct->task.pre_select = client_pre_select;
 459         ct->task.post_select = client_post_select;
 460         ct->task.error = 0;
 461         sprintf(ct->task.status, "client");
 462         register_task(s, &ct->task);
 463         return 1;
 464 err_out:
 465         close(ct->scc.fd);
 466         ct->scc.fd = -1;
 467         return ret;
 468 }
 469
 470 /**
 471  * Parse a client configuration.
 472  *
 473  * \param argc Usual argument count.
 474  * \param argv Usual argument vector.
 475  * \param ct_ptr Filled in by this function.
 476  * \param loglevel If not \p NULL, the number of the loglevel is stored here.
 477  *
 478  * This checks the command line options given by \a argc and \a argv, sets
 479  * default values for the user name and the name of the rsa key file and reads
 480  * further options from the config file.
 481  *
 482  * Upon successful return, \a ct_ptr points to a dynamically allocated and
 483  * initialized client task struct.
 484  *
 485  * \return The number of non-option arguments in \a argc/argv on success,
 486  * negative on errors.
 487  */
 488 int client_parse_config(int argc, char *argv[], struct client_task **ct_ptr,
 489                 int *loglevel)
 490 {
 491         char *home = para_homedir();
 492         int ret;
 493         struct client_task *ct = para_calloc(sizeof(struct client_task));
 494
 495         *ct_ptr = ct;
 496         ct->scc.fd = -1;
 497         ret = -E_CLIENT_SYNTAX;
 498         if (client_cmdline_parser(argc, argv, &ct->conf))
 499                 goto out;
 500         HANDLE_VERSION_FLAG("client", ct->conf);
 501
 502         ct->config_file = ct->conf.config_file_given?
 503                 para_strdup(ct->conf.config_file_arg) :
 504                 make_message("%s/.paraslash/client.conf", home);
 505         ret = file_exists(ct->config_file);
 506         if (!ret && ct->conf.config_file_given) {
 507                 ret = -E_NO_CONFIG;
 508                 goto out;
 509         }
 510         if (ret) {
 511                 struct client_cmdline_parser_params params = {
 512                         .override = 0,
 513                         .initialize = 0,
 514                         .check_required = 0,
 515                         .check_ambiguity = 0,
 516                         .print_errors = 0
 517                 };
 518                 ret = -E_BAD_CONFIG;
 519                 if (client_cmdline_parser_config_file(ct->config_file,
 520                         &ct->conf, &params))
 521                         goto out;
 522         }
 523         ct->user = ct->conf.user_given?
 524                 para_strdup(ct->conf.user_arg) : para_logname();
 525
 526         if (ct->conf.key_file_given)
 527                 ct->key_file = para_strdup(ct->conf.key_file_arg);
 528         else {
 529                 ct->key_file = make_message("%s/.paraslash/key.%s",
 530                         home, ct->user);
 531                 if (!file_exists(ct->key_file)) {
 532                         free(ct->key_file);
 533                         ct->key_file = make_message("%s/.ssh/id_rsa", home);
 534                 }
 535         }
 536
 537         if (loglevel)
 538                 *loglevel = get_loglevel_by_name(ct->conf.loglevel_arg);
 539         PARA_INFO_LOG("loglevel: %s\n", ct->conf.loglevel_arg);
 540         PARA_INFO_LOG("config_file: %s\n", ct->config_file);
 541         PARA_INFO_LOG("key_file: %s\n", ct->key_file);
 542         ret = ct->conf.inputs_num;
 543 out:
 544         free(home);
 545         if (ret < 0) {
 546                 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
 547                 client_close(ct);
 548                 *ct_ptr = NULL;
 549         }
 550         return ret;
 551 }
 552
 553 /**
 554  * Parse the client configuration and open a connection to para_server.
 555  *
 556  * \param argc See \ref client_parse_config.
 557  * \param argv See \ref client_parse_config.
 558  * \param ct_ptr See \ref client_parse_config.
 559  * \param loglevel See \ref client_parse_config.
 560  * \param parent See \ref client_connect().
 561  * \param child See \ref client_connect().
 562  * \param sched See \ref client_connect().
 563  *
 564  * This function combines client_parse_config() and client_connect(). It is
 565  * considered a syntax error if no command was given, i.e. if the number
 566  * of non-option arguments is zero.
 567  *
 568  * \return Standard.
 569  */
 570 int client_open(int argc, char *argv[], struct client_task **ct_ptr,
 571                 int *loglevel, struct btr_node *parent, struct btr_node *child,
 572                 struct sched *sched)
 573 {
 574         int ret = client_parse_config(argc, argv, ct_ptr, loglevel);
 575
 576         if (ret < 0)
 577                 return ret;
 578         if (ret == 0) {
 579                 ret = -E_CLIENT_SYNTAX;
 580                 goto fail;
 581         }
 582         ret = client_connect(*ct_ptr, sched, parent, child);
 583         if (ret < 0)
 584                 goto fail;
 585         return 1;
 586 fail:
 587         client_close(*ct_ptr);
 588         *ct_ptr = NULL;
 589         return ret;
 590 }