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 <netinet/in.h>
  10 #include <sys/socket.h>
  11 #include <regex.h>
  12 #include <sys/types.h>
  13 #include <arpa/inet.h>
  14 #include <sys/un.h>
  15 #include <netdb.h>
  16
  17 #include "para.h"
  18 #include "error.h"
  19 #include "list.h"
  20 #include "sched.h"
  21 #include "crypt.h"
  22 #include "net.h"
  23 #include "fd.h"
  24 #include "sideband.h"
  25 #include "string.h"
  26 #include "client.cmdline.h"
  27 #include "client.h"
  28 #include "buffer_tree.h"
  29 #include "version.h"
  30 #include "ggo.h"
  31
  32 /** The size of the receiving buffer. */
  33 #define CLIENT_BUFSIZE 4000
  34
  35 /**
  36  * Close the connection to para_server and deallocate per-command resources.
  37  *
  38  * \param ct The client task.
  39  *
  40  * This frees all resources of the current command but keeps the configuration
  41  * in \p ct->conf.
  42  *
  43  * \sa \ref client_close().
  44  */
  45 void client_disconnect(struct client_task *ct)
  46 {
  47         if (!ct)
  48                 return;
  49         if (ct->scc.fd >= 0)
  50                 close(ct->scc.fd);
  51         free_argv(ct->features);
  52         ct->features = NULL;
  53         sc_free(ct->scc.recv);
  54         ct->scc.recv = NULL;
  55         sc_free(ct->scc.send);
  56         ct->scc.send = NULL;
  57         btr_remove_node(&ct->btrn[0]);
  58         btr_remove_node(&ct->btrn[1]);
  59 }
  60
  61 /**
  62  * Close the connection to para_server and free all resources.
  63  *
  64  * \param ct Pointer to the client data.
  65  *
  66  * \sa \ref client_open(), \ref client_disconnect().
  67  */
  68 void client_close(struct client_task *ct)
  69 {
  70         if (!ct)
  71                 return;
  72         client_disconnect(ct);
  73         free(ct->user);
  74         free(ct->config_file);
  75         free(ct->key_file);
  76         client_cmdline_parser_free(&ct->conf);
  77         free(ct->challenge_hash);
  78         sb_free(ct->sbc[0]);
  79         sb_free(ct->sbc[1]);
  80         free(ct);
  81 }
  82
  83 /**
  84  * The preselect hook for server commands.
  85  *
  86  * \param s Pointer to the scheduler.
  87  * \param t Pointer to the task struct for this command.
  88  *
  89  * The task pointer must contain a pointer to the initialized client data
  90  * structure as it is returned by client_open().
  91  *
  92  * This function checks the state of the connection and adds the file descriptor
  93  * of the connection to the read or write fd set of \a s accordingly.
  94  *
  95  * \sa register_task() client_open(), struct sched, struct task.
  96  */
  97 static void client_pre_select(struct sched *s, struct task *t)
  98 {
  99         int ret;
 100         struct client_task *ct = container_of(t, struct client_task, task);
 101
 102         if (ct->scc.fd < 0)
 103                 return;
 104         switch (ct->status) {
 105         case CL_CONNECTED:
 106         case CL_SENT_AUTH:
 107         case CL_SENT_CH_RESPONSE:
 108                 para_fd_set(ct->scc.fd, &s->rfds, &s->max_fileno);
 109                 return;
 110
 111         case CL_RECEIVED_WELCOME:
 112         case CL_RECEIVED_PROCEED:
 113         case CL_RECEIVED_CHALLENGE:
 114                 para_fd_set(ct->scc.fd, &s->wfds, &s->max_fileno);
 115                 return;
 116
 117         case CL_SENDING:
 118                 if (ct->btrn[1]) {
 119                         ret = btr_node_status(ct->btrn[1], 0, BTR_NT_LEAF);
 120                         if (ret < 0)
 121                                 sched_min_delay(s);
 122                         else if (ret > 0)
 123                                 para_fd_set(ct->scc.fd, &s->wfds, &s->max_fileno);
 124                 }
 125                 /* fall though */
 126         case CL_EXECUTING:
 127                 if (ct->btrn[0]) {
 128                         ret = btr_node_status(ct->btrn[0], 0, BTR_NT_ROOT);
 129                         if (ret < 0)
 130                                 sched_min_delay(s);
 131                         else if (ret > 0)
 132                                 para_fd_set(ct->scc.fd, &s->rfds, &s->max_fileno);
 133                 }
 134                 return;
 135         }
 136 }
 137
 138 static int send_sb(struct client_task *ct, int channel, void *buf, size_t numbytes,
 139                 enum sb_designator band, bool dont_free)
 140 {
 141         int ret, fd = ct->scc.fd;
 142         struct iovec iov[2];
 143
 144         if (!ct->sbc[channel]) {
 145                 struct sb_buffer sbb;
 146                 sb_transformation trafo = ct->status < CL_RECEIVED_PROCEED?
 147                         NULL : sc_trafo;
 148                 sbb = (typeof(sbb))SBB_INIT(band, buf, numbytes);
 149                 ct->sbc[channel] = sb_new_send(&sbb, dont_free, trafo, ct->scc.send);
 150         }
 151         ret = sb_get_send_buffers(ct->sbc[channel], iov);
 152         ret = xwritev(fd, iov, ret);
 153         if (ret < 0) {
 154                 sb_free(ct->sbc[channel]);
 155                 ct->sbc[channel] = NULL;
 156                 return ret;
 157         }
 158         if (sb_sent(ct->sbc[channel], ret)) {
 159                 ct->sbc[channel] = NULL;
 160                 return 1;
 161         }
 162         return 0;
 163 }
 164
 165 static int recv_sb(struct client_task *ct, fd_set *rfds,
 166                 struct sb_buffer *result)
 167 {
 168         int ret;
 169         size_t n;
 170         sb_transformation trafo;
 171         void *trafo_context;
 172         struct iovec iov;
 173
 174         if (!FD_ISSET(ct->scc.fd, rfds))
 175                 return 0;
 176         if (ct->status < CL_SENT_CH_RESPONSE)
 177                 trafo = trafo_context = NULL;
 178         else {
 179                 trafo = sc_trafo;
 180                 trafo_context = ct->scc.recv;
 181         }
 182         if (!ct->sbc[0])
 183                 ct->sbc[0] = sb_new_recv(0, trafo, trafo_context);
 184 again:
 185         sb_get_recv_buffer(ct->sbc[0], &iov);
 186         ret = read_nonblock(ct->scc.fd, iov.iov_base, iov.iov_len, rfds, &n);
 187         if (ret < 0) {
 188                 sb_free(ct->sbc[0]);
 189                 ct->sbc[0] = NULL;
 190                 return ret;
 191         }
 192         if (n == 0)
 193                 return 0;
 194         if (!sb_received(ct->sbc[0], n, result))
 195                 goto again;
 196         ct->sbc[0] = NULL;
 197         return 1;
 198 }
 199
 200
 201 static char **parse_features(char *buf)
 202 {
 203         int i;
 204         const char id[] = "\nFeatures: ";
 205         char *p, *q, **features;
 206
 207         p = strstr(buf, id);
 208         if (!p)
 209                 return NULL;
 210         p += strlen(id);
 211         q = strchr(p, '\n');
 212         if (!q)
 213                 return NULL;
 214         *q = '\0';
 215         create_argv(p, ",", &features);
 216         for (i = 0; features[i]; i++)
 217                 PARA_INFO_LOG("server feature: %s\n", features[i]);
 218         return features;
 219 }
 220
 221 static int dispatch_sbb(struct client_task *ct, struct sb_buffer *sbb)
 222 {
 223         int ret;
 224         const char *designator[] = {SB_DESIGNATORS_ARRAY};
 225
 226         if (!sbb)
 227                 return 0;
 228         if (sbb->band < NUM_SB_DESIGNATORS)
 229                 PARA_DEBUG_LOG("band: %s\n", designator[sbb->band]);
 230
 231         switch (sbb->band) {
 232         case SBD_AWAITING_DATA:
 233                 ct->status = CL_SENDING;
 234                 ret = 1;
 235                 goto out;
 236         case SBD_OUTPUT:
 237                 if (iov_valid(&sbb->iov))
 238                         btr_add_output(sbb->iov.iov_base, sbb->iov.iov_len,
 239                                 ct->btrn[0]);
 240                 ret = 1;
 241                 goto out;
 242         case SBD_DEBUG_LOG:
 243         case SBD_INFO_LOG:
 244         case SBD_NOTICE_LOG:
 245         case SBD_WARNING_LOG:
 246         case SBD_ERROR_LOG:
 247         case SBD_CRIT_LOG:
 248         case SBD_EMERG_LOG:
 249                 if (iov_valid(&sbb->iov)) {
 250                         int ll = sbb->band - SBD_DEBUG_LOG;
 251                         para_log(ll, "remote: %s", (char *)sbb->iov.iov_base);
 252                 }
 253                 ret = 1;
 254                 goto deallocate;
 255         case SBD_EXIT__SUCCESS:
 256                 ret = -E_SERVER_CMD_SUCCESS;
 257                 goto deallocate;
 258         case SBD_EXIT__FAILURE:
 259                 ret = -E_SERVER_CMD_FAILURE;
 260                 goto deallocate;
 261         default:
 262                 PARA_ERROR_LOG("invalid band %d\n", sbb->band);
 263                 ret = -E_BAD_BAND;
 264                 goto deallocate;
 265         }
 266 deallocate:
 267         free(sbb->iov.iov_base);
 268 out:
 269         sbb->iov.iov_base = NULL;
 270         return ret;
 271 }
 272
 273 static bool has_feature(const char *feature, struct client_task *ct)
 274 {
 275         return find_arg(feature, ct->features) >= 0? true : false;
 276 }
 277
 278 static int send_sb_command(struct client_task *ct)
 279 {
 280         int i;
 281         char *command, *p;
 282         size_t len = 0;
 283
 284         if (ct->sbc[1])
 285                 return send_sb(ct, 0, NULL, 0, 0, false);
 286
 287         for (i = 0; i < ct->conf.inputs_num; i++)
 288                 len += strlen(ct->conf.inputs[i]) + 1;
 289         p = command = para_malloc(len);
 290         for (i = 0; i < ct->conf.inputs_num; i++) {
 291                 strcpy(p, ct->conf.inputs[i]);
 292                 p += strlen(ct->conf.inputs[i]) + 1;
 293         }
 294         PARA_DEBUG_LOG("--> %s\n", command);
 295         return send_sb(ct, 0, command, len, SBD_COMMAND, false);
 296 }
 297
 298 /**
 299  * The post select hook for client commands.
 300  *
 301  * \param s Pointer to the scheduler.
 302  * \param t Pointer to the task struct for this command.
 303  *
 304  * Depending on the current state of the connection and the status of the read
 305  * and write fd sets of \a s, this function performs the necessary steps to
 306  * authenticate the connection, to send the command given by \a t->private_data
 307  * and to receive para_server's output, if any.
 308  *
 309  * \sa struct sched, struct task.
 310  */
 311 static int client_post_select(struct sched *s, struct task *t)
 312 {
 313         struct client_task *ct = container_of(t, struct client_task, task);
 314         int ret = 0;
 315         size_t n;
 316         char buf[CLIENT_BUFSIZE];
 317
 318         ret = task_get_notification(t);
 319         if (ret < 0)
 320                 goto out;
 321         if (ct->scc.fd < 0)
 322                 return 0;
 323         switch (ct->status) {
 324         case CL_CONNECTED: /* receive welcome message */
 325                 ret = read_nonblock(ct->scc.fd, buf, sizeof(buf), &s->rfds, &n);
 326                 if (ret < 0 || n == 0)
 327                         goto out;
 328                 ct->features = parse_features(buf);
 329                 if (!has_feature("sideband", ct)) {
 330                         PARA_ERROR_LOG("server has no sideband support\n");
 331                         ret = -E_INCOMPAT_FEAT;
 332                         goto out;
 333                 }
 334                 ct->status = CL_RECEIVED_WELCOME;
 335                 return 0;
 336         case CL_RECEIVED_WELCOME: /* send auth command */
 337                 if (!FD_ISSET(ct->scc.fd, &s->wfds))
 338                         return 0;
 339                 sprintf(buf, AUTH_REQUEST_MSG "%s sideband%s", ct->user,
 340                         has_feature("aes_ctr128", ct)? ",aes_ctr128" : "");
 341                 PARA_INFO_LOG("--> %s\n", buf);
 342                 ret = write_buffer(ct->scc.fd, buf);
 343                 if (ret < 0)
 344                         goto out;
 345                 ct->status = CL_SENT_AUTH;
 346                 return 0;
 347         case CL_SENT_AUTH:
 348                 /*
 349                  * Receive challenge and session keys, decrypt the challenge and
 350                  * send back the hash of the decrypted challenge.
 351                  */
 352                 {
 353                 /* decrypted challenge/session key buffer */
 354                 unsigned char crypt_buf[1024];
 355                 struct sb_buffer sbb;
 356                 bool use_aes;
 357
 358                 ret = recv_sb(ct, &s->rfds, &sbb);
 359                 if (ret <= 0)
 360                         goto out;
 361                 if (sbb.band != SBD_CHALLENGE) {
 362                         ret = -E_BAD_BAND;
 363                         free(sbb.iov.iov_base);
 364                                 goto out;
 365                 }
 366                 n = sbb.iov.iov_len;
 367                 PARA_INFO_LOG("<-- [challenge] (%zu bytes)\n", n);
 368                 ret = priv_decrypt(ct->key_file, crypt_buf,
 369                         sbb.iov.iov_base, n);
 370                 free(sbb.iov.iov_base);
 371                 if (ret < 0)
 372                         goto out;
 373                 ct->challenge_hash = para_malloc(HASH_SIZE);
 374                 hash_function((char *)crypt_buf, CHALLENGE_SIZE, ct->challenge_hash);
 375                 use_aes = has_feature("aes_ctr128", ct);
 376                 ct->scc.send = sc_new(crypt_buf + CHALLENGE_SIZE, SESSION_KEY_LEN, use_aes);
 377                 ct->scc.recv = sc_new(crypt_buf + CHALLENGE_SIZE + SESSION_KEY_LEN,
 378                         SESSION_KEY_LEN, use_aes);
 379                 hash_to_asc(ct->challenge_hash, buf);
 380                 PARA_INFO_LOG("--> %s\n", buf);
 381                 ct->status = CL_RECEIVED_CHALLENGE;
 382                 return 0;
 383                 }
 384         case CL_RECEIVED_CHALLENGE:
 385                 ret = send_sb(ct, 0, ct->challenge_hash, HASH_SIZE,
 386                         SBD_CHALLENGE_RESPONSE, false);
 387                 if (ret != 0)
 388                         ct->challenge_hash = NULL;
 389                 if (ret <= 0)
 390                         goto out;
 391                 ct->status = CL_SENT_CH_RESPONSE;
 392                 goto out;
 393         case CL_SENT_CH_RESPONSE: /* read server response */
 394                 {
 395                 struct sb_buffer sbb;
 396                 ret = recv_sb(ct, &s->rfds, &sbb);
 397                 if (ret <= 0)
 398                         goto out;
 399                 free(sbb.iov.iov_base);
 400                 if (sbb.band != SBD_PROCEED)
 401                         ret = -E_BAD_BAND;
 402                 else
 403                         ct->status = CL_RECEIVED_PROCEED;
 404                 goto out;
 405                 }
 406         case CL_RECEIVED_PROCEED: /* concat args and send command */
 407                 {
 408                 if (!FD_ISSET(ct->scc.fd, &s->wfds))
 409                         return 0;
 410                 ret = send_sb_command(ct);
 411                 if (ret <= 0)
 412                         goto out;
 413                 ct->status = CL_EXECUTING;
 414                 return 0;
 415                 }
 416         case CL_SENDING:
 417                 if (ct->btrn[1]) {
 418                         char *buf2;
 419                         size_t sz;
 420                         ret = btr_node_status(ct->btrn[1], 0, BTR_NT_LEAF);
 421                         if (ret == -E_BTR_EOF) {
 422                                 /* empty blob data packet indicates EOF */
 423                                 PARA_INFO_LOG("blob sent\n");
 424                                 ret = send_sb(ct, 1, NULL, 0, SBD_BLOB_DATA, true);
 425                                 if (ret >= 0)
 426                                         ret = -E_BTR_EOF;
 427                         }
 428                         if (ret < 0)
 429                                 goto close1;
 430                         if (ret > 0 && FD_ISSET(ct->scc.fd, &s->wfds)) {
 431                                 sz = btr_next_buffer(ct->btrn[1], &buf2);
 432                                 assert(sz);
 433                                 ret = send_sb(ct, 1, buf2, sz, SBD_BLOB_DATA, true);
 434                                 if (ret < 0)
 435                                         goto close1;
 436                                 if (ret > 0)
 437                                         btr_consume(ct->btrn[1], sz);
 438                         }
 439                 }
 440                 /* fall though */
 441         case CL_EXECUTING:
 442                 if (ct->btrn[0]) {
 443                         ret = btr_node_status(ct->btrn[0], 0, BTR_NT_ROOT);
 444                         if (ret < 0)
 445                                 goto close0;
 446                         if (ret > 0 && FD_ISSET(ct->scc.fd, &s->rfds)) {
 447                                 struct sb_buffer sbb;
 448                                 ret = recv_sb(ct, &s->rfds, &sbb);
 449                                 if (ret < 0)
 450                                         goto close0;
 451                                 if (ret > 0) {
 452                                         ret = dispatch_sbb(ct, &sbb);
 453                                         if (ret < 0)
 454                                                 goto close0;
 455                                 }
 456                         }
 457                 }
 458                 ret = 0;
 459                 goto out;
 460         }
 461 close1:
 462         PARA_INFO_LOG("channel 1: %s\n", para_strerror(-ret));
 463         btr_remove_node(&ct->btrn[1]);
 464         if (ct->btrn[0])
 465                 return 0;
 466         goto out;
 467 close0:
 468         PARA_INFO_LOG("channel 0: %s\n", para_strerror(-ret));
 469         btr_remove_node(&ct->btrn[0]);
 470         if (ct->btrn[1] && ct->status == CL_SENDING)
 471                 return 0;
 472 out:
 473         if (ret >= 0)
 474                 return 0;
 475         btr_remove_node(&ct->btrn[0]);
 476         btr_remove_node(&ct->btrn[1]);
 477         if (ret != -E_SERVER_CMD_SUCCESS && ret != -E_SERVER_CMD_FAILURE)
 478                 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
 479         return ret;
 480 }
 481
 482 /**
 483  * Connect to para_server and register the client task.
 484  *
 485  * \param ct The initialized client task structure.
 486  * \param s The scheduler instance to register the client task to.
 487  * \param parent The parent node of the client btr node.
 488  * \param child The child node of the client node.
 489  *
 490  * The client task structure given by \a ct  must be allocated and initialized
 491  * by \ref client_parse_config() before this function is called.
 492  *
 493  * \return Standard.
 494  */
 495 int client_connect(struct client_task *ct, struct sched *s,
 496                 struct btr_node *parent, struct btr_node *child)
 497 {
 498         int ret;
 499
 500         PARA_NOTICE_LOG("connecting %s:%d\n", ct->conf.hostname_arg,
 501                 ct->conf.server_port_arg);
 502         ct->scc.fd = -1;
 503         ret = para_connect_simple(IPPROTO_TCP, ct->conf.hostname_arg,
 504                                                ct->conf.server_port_arg);
 505         if (ret < 0)
 506                 return ret;
 507         ct->scc.fd = ret;
 508         ret = mark_fd_nonblocking(ct->scc.fd);
 509         if (ret < 0)
 510                 goto err_out;
 511         ct->status = CL_CONNECTED;
 512         ct->btrn[0] = btr_new_node(&(struct btr_node_description)
 513                 EMBRACE(.name = "client recv", .parent = NULL, .child = child));
 514         ct->btrn[1] = btr_new_node(&(struct btr_node_description)
 515                 EMBRACE(.name = "client send", .parent = parent, .child = NULL));
 516         ct->task.pre_select = client_pre_select;
 517         ct->task.post_select = client_post_select;
 518         ct->task.error = 0;
 519         sprintf(ct->task.status, "client");
 520         register_task(s, &ct->task);
 521         return 1;
 522 err_out:
 523         close(ct->scc.fd);
 524         ct->scc.fd = -1;
 525         return ret;
 526 }
 527
 528 __noreturn static void print_help_and_die(struct client_task *ct)
 529 {
 530         struct ggo_help h = DEFINE_GGO_HELP(client);
 531         bool d = ct->conf.detailed_help_given;
 532
 533         ggo_print_help(&h, d? GPH_STANDARD_FLAGS_DETAILED : GPH_STANDARD_FLAGS);
 534         exit(0);
 535 }
 536
 537 /**
 538  * Parse a client configuration.
 539  *
 540  * \param argc Usual argument count.
 541  * \param argv Usual argument vector.
 542  * \param ct_ptr Filled in by this function.
 543  * \param loglevel If not \p NULL, the number of the loglevel is stored here.
 544  *
 545  * This checks the command line options given by \a argc and \a argv, sets
 546  * default values for the user name and the name of the rsa key file and reads
 547  * further options from the config file.
 548  *
 549  * Upon successful return, \a ct_ptr points to a dynamically allocated and
 550  * initialized client task struct.
 551  *
 552  * \return The number of non-option arguments in \a argc/argv on success,
 553  * negative on errors.
 554  */
 555 int client_parse_config(int argc, char *argv[], struct client_task **ct_ptr,
 556                 int *loglevel)
 557 {
 558         char *home = para_homedir();
 559         int ret;
 560         struct client_task *ct = para_calloc(sizeof(struct client_task));
 561
 562         *ct_ptr = ct;
 563         ct->scc.fd = -1;
 564         ret = -E_CLIENT_SYNTAX;
 565         if (client_cmdline_parser(argc, argv, &ct->conf))
 566                 goto out;
 567         version_handle_flag("client", ct->conf.version_given);
 568         if (ct->conf.help_given || ct->conf.detailed_help_given)
 569                 print_help_and_die(ct);
 570
 571         ct->config_file = ct->conf.config_file_given?
 572                 para_strdup(ct->conf.config_file_arg) :
 573                 make_message("%s/.paraslash/client.conf", home);
 574         ret = file_exists(ct->config_file);
 575         if (!ret && ct->conf.config_file_given) {
 576                 ret = -E_NO_CONFIG;
 577                 goto out;
 578         }
 579         if (ret) {
 580                 struct client_cmdline_parser_params params = {
 581                         .override = 0,
 582                         .initialize = 0,
 583                         .check_required = 0,
 584                         .check_ambiguity = 0,
 585                         .print_errors = 0
 586                 };
 587                 ret = -E_BAD_CONFIG;
 588                 if (client_cmdline_parser_config_file(ct->config_file,
 589                         &ct->conf, &params))
 590                         goto out;
 591         }
 592         ct->user = ct->conf.user_given?
 593                 para_strdup(ct->conf.user_arg) : para_logname();
 594
 595         if (ct->conf.key_file_given)
 596                 ct->key_file = para_strdup(ct->conf.key_file_arg);
 597         else {
 598                 ct->key_file = make_message("%s/.paraslash/key.%s",
 599                         home, ct->user);
 600                 if (!file_exists(ct->key_file)) {
 601                         free(ct->key_file);
 602                         ct->key_file = make_message("%s/.ssh/id_rsa", home);
 603                 }
 604         }
 605
 606         if (loglevel)
 607                 *loglevel = get_loglevel_by_name(ct->conf.loglevel_arg);
 608         PARA_INFO_LOG("loglevel: %s\n", ct->conf.loglevel_arg);
 609         PARA_INFO_LOG("config_file: %s\n", ct->config_file);
 610         PARA_INFO_LOG("key_file: %s\n", ct->key_file);
 611         ret = ct->conf.inputs_num;
 612 out:
 613         free(home);
 614         if (ret < 0) {
 615                 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
 616                 client_close(ct);
 617                 *ct_ptr = NULL;
 618         }
 619         return ret;
 620 }
 621
 622 /**
 623  * Parse the client configuration and open a connection to para_server.
 624  *
 625  * \param argc See \ref client_parse_config.
 626  * \param argv See \ref client_parse_config.
 627  * \param ct_ptr See \ref client_parse_config.
 628  * \param loglevel See \ref client_parse_config.
 629  * \param parent See \ref client_connect().
 630  * \param child See \ref client_connect().
 631  * \param sched See \ref client_connect().
 632  *
 633  * This function combines client_parse_config() and client_connect(). It is
 634  * considered a syntax error if no command was given, i.e. if the number
 635  * of non-option arguments is zero.
 636  *
 637  * \return Standard.
 638  */
 639 int client_open(int argc, char *argv[], struct client_task **ct_ptr,
 640                 int *loglevel, struct btr_node *parent, struct btr_node *child,
 641                 struct sched *sched)
 642 {
 643         int ret = client_parse_config(argc, argv, ct_ptr, loglevel);
 644
 645         if (ret < 0)
 646                 return ret;
 647         if (ret == 0) {
 648                 ret = -E_CLIENT_SYNTAX;
 649                 goto fail;
 650         }
 651         ret = client_connect(*ct_ptr, sched, parent, child);
 652         if (ret < 0)
 653                 goto fail;
 654         return 1;
 655 fail:
 656         client_close(*ct_ptr);
 657         *ct_ptr = NULL;
 658         return ret;
 659 }