client_common.c

   1 /* Copyright (C) 1997 Andre Noll <maan@tuebingen.mpg.de>, see file COPYING. */
   2
   3 /** \file client_common.c Common functions of para_client and para_audiod. */
   4
   5 #include <netinet/in.h>
   6 #include <sys/socket.h>
   7 #include <regex.h>
   8 #include <sys/types.h>
   9 #include <arpa/inet.h>
  10 #include <sys/un.h>
  11 #include <netdb.h>
  12 #include <lopsub.h>
  13
  14 #include "client.lsg.h"
  15 #include "para.h"
  16 #include "error.h"
  17 #include "list.h"
  18 #include "lsu.h"
  19 #include "sched.h"
  20 #include "crypt.h"
  21 #include "net.h"
  22 #include "fd.h"
  23 #include "sideband.h"
  24 #include "string.h"
  25 #include "client.h"
  26 #include "buffer_tree.h"
  27 #include "version.h"
  28
  29 /** The size of the receiving buffer. */
  30 #define CLIENT_BUFSIZE 4000
  31
  32 /**
  33  * Close the connection to para_server and free all resources.
  34  *
  35  * \param ct Pointer to the client data.
  36  *
  37  * \sa \ref client_open().
  38  */
  39 void client_close(struct client_task *ct)
  40 {
  41         if (!ct)
  42                 return;
  43         free(ct->user);
  44         free(ct->key_file);
  45         lls_free_parse_result(ct->lpr, CLIENT_CMD_PTR);
  46         free(ct->challenge_hash);
  47         sb_free(ct->sbc[0]);
  48         sb_free(ct->sbc[1]);
  49         free(ct);
  50 }
  51
  52 /*
  53  * This function asks the scheduler to monitor a file descriptor which
  54  * corresponds to an active connection. The descriptor is monitored for either
  55  * reading or writing, depending on the state of the connection.
  56  *
  57  * The context pointer is assumed to refer to a client task structure that was
  58  * initialized earlier by client_open().
  59  */
  60 static void client_pre_monitor(struct sched *s, void *context)
  61 {
  62         int ret;
  63         struct client_task *ct = context;
  64
  65         if (ct->scc.fd < 0)
  66                 return;
  67         switch (ct->status) {
  68         case CL_CONNECTED:
  69         case CL_SENT_AUTH:
  70         case CL_SENT_CH_RESPONSE:
  71                 sched_monitor_readfd(ct->scc.fd, s);
  72                 return;
  73
  74         case CL_RECEIVED_WELCOME:
  75         case CL_RECEIVED_PROCEED:
  76         case CL_RECEIVED_CHALLENGE:
  77                 sched_monitor_writefd(ct->scc.fd, s);
  78                 return;
  79
  80         case CL_SENDING:
  81                 if (ct->btrn[1]) {
  82                         ret = btr_node_status(ct->btrn[1], 0, BTR_NT_LEAF);
  83                         if (ret < 0)
  84                                 sched_min_delay(s);
  85                         else if (ret > 0)
  86                                 sched_monitor_writefd(ct->scc.fd, s);
  87                 }
  88                 __attribute__ ((fallthrough));
  89         case CL_EXECUTING:
  90                 if (ct->btrn[0]) {
  91                         ret = btr_node_status(ct->btrn[0], 0, BTR_NT_ROOT);
  92                         if (ret < 0)
  93                                 sched_min_delay(s);
  94                         else if (ret > 0)
  95                                 sched_monitor_readfd(ct->scc.fd, s);
  96                 }
  97                 return;
  98         }
  99 }
 100
 101 static int send_sb(struct client_task *ct, int channel, void *buf, size_t numbytes,
 102                 enum sb_designator band, bool dont_free)
 103 {
 104         int ret, fd = ct->scc.fd;
 105         struct iovec iov[2];
 106
 107         if (!ct->sbc[channel]) {
 108                 struct sb_buffer sbb;
 109                 sb_transformation trafo = ct->status < CL_RECEIVED_PROCEED?
 110                         NULL : sc_trafo;
 111                 sbb = (typeof(sbb))SBB_INIT(band, buf, numbytes);
 112                 ct->sbc[channel] = sb_new_send(&sbb, dont_free, trafo, ct->scc.send);
 113         }
 114         ret = sb_get_send_buffers(ct->sbc[channel], iov);
 115         ret = xwritev(fd, iov, ret);
 116         if (ret < 0) {
 117                 sb_free(ct->sbc[channel]);
 118                 ct->sbc[channel] = NULL;
 119                 return ret;
 120         }
 121         if (sb_sent(ct->sbc[channel], ret)) {
 122                 ct->sbc[channel] = NULL;
 123                 return 1;
 124         }
 125         return 0;
 126 }
 127
 128 static int recv_sb(struct client_task *ct, struct sb_buffer *result)
 129 {
 130         int ret;
 131         size_t n;
 132         sb_transformation trafo;
 133         void *trafo_context;
 134         struct iovec iov;
 135
 136         if (ct->status < CL_SENT_CH_RESPONSE)
 137                 trafo = trafo_context = NULL;
 138         else {
 139                 trafo = sc_trafo;
 140                 trafo_context = ct->scc.recv;
 141         }
 142         if (!ct->sbc[0])
 143                 ct->sbc[0] = sb_new_recv(0, trafo, trafo_context);
 144 again:
 145         sb_get_recv_buffer(ct->sbc[0], &iov);
 146         ret = read_nonblock(ct->scc.fd, iov.iov_base, iov.iov_len, &n);
 147         if (ret < 0) {
 148                 sb_free(ct->sbc[0]);
 149                 ct->sbc[0] = NULL;
 150                 return ret;
 151         }
 152         if (n == 0)
 153                 return 0;
 154         ret = sb_received(ct->sbc[0], n, result);
 155         if (ret < 0)
 156                 return ret;
 157         if (ret == 0)
 158                 goto again;
 159         ct->sbc[0] = NULL;
 160         return 1;
 161 }
 162
 163
 164 static char **parse_features(char *buf)
 165 {
 166         int i;
 167         const char id[] = "\nFeatures: ";
 168         char *p, *q, **features;
 169
 170         p = strstr(buf, id);
 171         if (!p)
 172                 return NULL;
 173         p += strlen(id);
 174         q = strchr(p, '\n');
 175         if (!q)
 176                 return NULL;
 177         *q = '\0';
 178         create_argv(p, ",", &features);
 179         for (i = 0; features[i]; i++)
 180                 PARA_INFO_LOG("server feature: %s\n", features[i]);
 181         return features;
 182 }
 183
 184 static int dispatch_sbb(struct client_task *ct, struct sb_buffer *sbb)
 185 {
 186         int ret;
 187         const char *designator[] = {SB_DESIGNATORS_ARRAY};
 188
 189         if (!sbb)
 190                 return 0;
 191         if (sbb->band < NUM_SB_DESIGNATORS)
 192                 PARA_DEBUG_LOG("band: %s\n", designator[sbb->band]);
 193
 194         switch (sbb->band) {
 195         case SBD_AWAITING_DATA:
 196                 ct->status = CL_SENDING;
 197                 ret = 1;
 198                 goto out;
 199         case SBD_OUTPUT:
 200                 if (iov_valid(&sbb->iov))
 201                         btr_add_output(sbb->iov.iov_base, sbb->iov.iov_len,
 202                                 ct->btrn[0]);
 203                 ret = 1;
 204                 goto out;
 205         case SBD_DEBUG_LOG:
 206         case SBD_INFO_LOG:
 207         case SBD_NOTICE_LOG:
 208         case SBD_WARNING_LOG:
 209         case SBD_ERROR_LOG:
 210         case SBD_CRIT_LOG:
 211         case SBD_EMERG_LOG:
 212                 if (iov_valid(&sbb->iov)) {
 213                         int ll = sbb->band - SBD_DEBUG_LOG;
 214                         para_log(ll, "remote: %s", (char *)sbb->iov.iov_base);
 215                 }
 216                 ret = 1;
 217                 goto deallocate;
 218         case SBD_EXIT__SUCCESS:
 219                 ret = -E_SERVER_CMD_SUCCESS;
 220                 goto deallocate;
 221         case SBD_EXIT__FAILURE:
 222                 ret = -E_SERVER_CMD_FAILURE;
 223                 goto deallocate;
 224         default:
 225                 PARA_ERROR_LOG("invalid band %d\n", sbb->band);
 226                 ret = -E_BAD_BAND;
 227                 goto deallocate;
 228         }
 229 deallocate:
 230         free(sbb->iov.iov_base);
 231 out:
 232         sbb->iov.iov_base = NULL;
 233         return ret;
 234 }
 235
 236 static int send_sb_command(struct client_task *ct)
 237 {
 238         int i;
 239         char *command, *p;
 240         size_t len = 0;
 241         unsigned num_inputs = lls_num_inputs(ct->lpr);
 242
 243         if (ct->sbc[1])
 244                 return send_sb(ct, 0, NULL, 0, 0, false);
 245
 246         for (i = 0; i < num_inputs; i++)
 247                 len += strlen(lls_input(i, ct->lpr)) + 1;
 248         p = command = alloc(len);
 249         for (i = 0; i < num_inputs; i++) {
 250                 const char *str = lls_input(i, ct->lpr);
 251                 strcpy(p, str);
 252                 p += strlen(str) + 1;
 253         }
 254         PARA_DEBUG_LOG("--> %s\n", command);
 255         return send_sb(ct, 0, command, len, SBD_COMMAND, false);
 256 }
 257
 258 /* Find out if the given string is contained in the features vector. */
 259 static bool has_feature(const char *feature, struct client_task *ct)
 260 {
 261         if (!ct->features)
 262                 return false;
 263         for (int i = 0; ct->features[i]; i++)
 264                 if (strcmp(feature, ct->features[i]) == 0)
 265                         return i;
 266         return false;
 267 }
 268
 269 /*
 270  * This function reads or writes to the socket file descriptor which
 271  * corresponds to an established connection between the client and the server.
 272  * It depends on the current state of the connection and on the readiness of
 273  * the socket file descriptor which type of I/O is going to be performed.
 274  * Besides the initial handshake and authentication, the function sends the
 275  * server command and receives the output from the server, if any.
 276  *
 277  * The context pointer refers to a client task structure that was initialized
 278  * earlier by client_open().
 279  */
 280 static int client_post_monitor(struct sched *s, void *context)
 281 {
 282         struct client_task *ct = context;
 283         int ret = 0;
 284         size_t n;
 285         char buf[CLIENT_BUFSIZE];
 286
 287         ret = task_get_notification(ct->task);
 288         if (ret < 0)
 289                 goto out;
 290         if (ct->scc.fd < 0)
 291                 return 0;
 292         switch (ct->status) {
 293         case CL_CONNECTED: /* receive welcome message */
 294                 ret = read_nonblock(ct->scc.fd, buf, sizeof(buf), &n);
 295                 if (ret < 0 || n == 0)
 296                         goto out;
 297                 ct->features = parse_features(buf);
 298                 ct->status = CL_RECEIVED_WELCOME;
 299                 return 0;
 300         case CL_RECEIVED_WELCOME: /* send auth command */
 301                 {
 302                 /*
 303                  * Use sha256 iff the server announced the feature. After 0.7.0
 304                  * we may request and use the feature unconditionally. After
 305                  * 0.8.0 we no longer need to request the feature.
 306                  */
 307                 bool has_sha256;
 308                 if (!sched_write_ok(ct->scc.fd, s))
 309                         return 0;
 310                 has_sha256 = has_feature("sha256", ct);
 311                 sprintf(buf, AUTH_REQUEST_MSG "%s%s", ct->user, has_sha256?
 312                         " sha256" : "");
 313                 PARA_INFO_LOG("--> %s\n", buf);
 314                 ret = write_buffer(ct->scc.fd, buf);
 315                 if (ret < 0)
 316                         goto out;
 317                 ct->status = CL_SENT_AUTH;
 318                 return 0;
 319                 }
 320         case CL_SENT_AUTH:
 321                 /*
 322                  * Receive challenge and session keys, decrypt the challenge and
 323                  * send back the hash of the decrypted challenge.
 324                  */
 325                 {
 326                 /* decrypted challenge/session key buffer */
 327                 unsigned char crypt_buf[1024];
 328                 struct sb_buffer sbb;
 329
 330                 ret = recv_sb(ct, &sbb);
 331                 if (ret <= 0)
 332                         goto out;
 333                 if (sbb.band != SBD_CHALLENGE) {
 334                         ret = -E_BAD_BAND;
 335                         free(sbb.iov.iov_base);
 336                                 goto out;
 337                 }
 338                 n = sbb.iov.iov_len;
 339                 PARA_INFO_LOG("<-- [challenge] (%zu bytes)\n", n);
 340                 ret = apc_priv_decrypt(ct->key_file, crypt_buf,
 341                         sbb.iov.iov_base, n);
 342                 free(sbb.iov.iov_base);
 343                 if (ret < 0)
 344                         goto out;
 345                 ct->challenge_hash = alloc(HASH2_SIZE);
 346                 if (has_feature("sha256", ct)) {
 347                         hash2_function((char *)crypt_buf, APC_CHALLENGE_SIZE, ct->challenge_hash);
 348                         hash2_to_asc(ct->challenge_hash, buf);
 349                 } else {
 350                         hash_function((char *)crypt_buf, APC_CHALLENGE_SIZE, ct->challenge_hash);
 351                         hash_to_asc(ct->challenge_hash, buf);
 352                 }
 353                 ct->scc.send = sc_new(crypt_buf + APC_CHALLENGE_SIZE, SESSION_KEY_LEN);
 354                 ct->scc.recv = sc_new(crypt_buf + APC_CHALLENGE_SIZE + SESSION_KEY_LEN,
 355                         SESSION_KEY_LEN);
 356                 PARA_INFO_LOG("--> %s\n", buf);
 357                 ct->status = CL_RECEIVED_CHALLENGE;
 358                 return 0;
 359                 }
 360         case CL_RECEIVED_CHALLENGE:
 361                 if (has_feature("sha256", ct))
 362                         ret = send_sb(ct, 0, ct->challenge_hash, HASH2_SIZE,
 363                                 SBD_CHALLENGE_RESPONSE, false);
 364                 else
 365                         ret = send_sb(ct, 0, ct->challenge_hash, HASH_SIZE,
 366                                 SBD_CHALLENGE_RESPONSE, false);
 367                 if (ret != 0)
 368                         ct->challenge_hash = NULL;
 369                 if (ret <= 0)
 370                         goto out;
 371                 ct->status = CL_SENT_CH_RESPONSE;
 372                 goto out;
 373         case CL_SENT_CH_RESPONSE: /* read server response */
 374                 {
 375                 struct sb_buffer sbb;
 376                 ret = recv_sb(ct, &sbb);
 377                 if (ret <= 0)
 378                         goto out;
 379                 free(sbb.iov.iov_base);
 380                 if (sbb.band != SBD_PROCEED)
 381                         ret = -E_BAD_BAND;
 382                 else
 383                         ct->status = CL_RECEIVED_PROCEED;
 384                 goto out;
 385                 }
 386         case CL_RECEIVED_PROCEED: /* concat args and send command */
 387                 {
 388                 if (!sched_write_ok(ct->scc.fd, s))
 389                         return 0;
 390                 ret = send_sb_command(ct);
 391                 if (ret <= 0)
 392                         goto out;
 393                 ct->status = CL_EXECUTING;
 394                 return 0;
 395                 }
 396         case CL_SENDING:
 397                 if (ct->btrn[1]) {
 398                         char *buf2;
 399                         size_t sz;
 400                         ret = btr_node_status(ct->btrn[1], 0, BTR_NT_LEAF);
 401                         if (ret == -E_BTR_EOF) {
 402                                 /* empty blob data packet indicates EOF */
 403                                 PARA_INFO_LOG("blob sent\n");
 404                                 ret = send_sb(ct, 1, NULL, 0, SBD_BLOB_DATA, true);
 405                                 if (ret >= 0)
 406                                         ret = -E_BTR_EOF;
 407                         }
 408                         if (ret < 0)
 409                                 goto close1;
 410                         if (ret > 0 && sched_write_ok(ct->scc.fd, s)) {
 411                                 sz = btr_next_buffer(ct->btrn[1], &buf2);
 412                                 assert(sz);
 413                                 ret = send_sb(ct, 1, buf2, sz, SBD_BLOB_DATA, true);
 414                                 if (ret < 0)
 415                                         goto close1;
 416                                 if (ret > 0)
 417                                         btr_consume(ct->btrn[1], sz);
 418                         }
 419                 }
 420                 __attribute__ ((fallthrough));
 421         case CL_EXECUTING:
 422                 if (ct->btrn[0]) {
 423                         ret = btr_node_status(ct->btrn[0], 0, BTR_NT_ROOT);
 424                         if (ret < 0)
 425                                 goto close0;
 426                         if (ret > 0 && sched_read_ok(ct->scc.fd, s)) {
 427                                 struct sb_buffer sbb;
 428                                 ret = recv_sb(ct, &sbb);
 429                                 if (ret < 0)
 430                                         goto close0;
 431                                 if (ret > 0) {
 432                                         ret = dispatch_sbb(ct, &sbb);
 433                                         if (ret < 0)
 434                                                 goto close0;
 435                                 }
 436                         }
 437                 }
 438                 ret = 0;
 439                 goto out;
 440         }
 441 close1:
 442         PARA_INFO_LOG("channel 1: %s\n", para_strerror(-ret));
 443         btr_remove_node(&ct->btrn[1]);
 444         if (ct->btrn[0])
 445                 return 0;
 446         goto out;
 447 close0:
 448         PARA_INFO_LOG("channel 0: %s\n", para_strerror(-ret));
 449         btr_remove_node(&ct->btrn[0]);
 450         if (ct->btrn[1] && ct->status == CL_SENDING)
 451                 return 0;
 452 out:
 453         if (ret >= 0)
 454                 return 0;
 455         btr_remove_node(&ct->btrn[0]);
 456         btr_remove_node(&ct->btrn[1]);
 457         PARA_NOTICE_LOG("closing connection (%s)\n", para_strerror(-ret));
 458         if (ct->scc.fd >= 0) {
 459                 close(ct->scc.fd);
 460                 ct->scc.fd = -1;
 461         }
 462         free_argv(ct->features);
 463         ct->features = NULL;
 464         sc_free(ct->scc.recv);
 465         ct->scc.recv = NULL;
 466         sc_free(ct->scc.send);
 467         ct->scc.send = NULL;
 468         return ret;
 469 }
 470
 471 /**
 472  * Connect to para_server and register the client task.
 473  *
 474  * \param ct The initialized client task structure.
 475  * \param s The scheduler instance to register the client task to.
 476  * \param parent The parent node of the client btr node.
 477  * \param child The child node of the client node.
 478  *
 479  * The client task structure given by \a ct  must be allocated and initialized
 480  * by \ref client_parse_config() before this function is called.
 481  *
 482  * \return Standard.
 483  */
 484 int client_connect(struct client_task *ct, struct sched *s,
 485                 struct btr_node *parent, struct btr_node *child)
 486 {
 487         int ret;
 488         const char *host = CLIENT_OPT_STRING_VAL(HOSTNAME, ct->lpr);
 489         uint32_t port = CLIENT_OPT_UINT32_VAL(SERVER_PORT, ct->lpr);
 490
 491         PARA_NOTICE_LOG("connecting %s:%u\n", host, port);
 492         ct->scc.fd = -1;
 493         ret = para_connect(IPPROTO_TCP, host, port);
 494         if (ret < 0)
 495                 return ret;
 496         ct->scc.fd = ret;
 497         ret = mark_fd_nonblocking(ct->scc.fd);
 498         if (ret < 0)
 499                 goto err_out;
 500         ct->status = CL_CONNECTED;
 501         ct->btrn[0] = btr_new_node(&(struct btr_node_description)
 502                 EMBRACE(.name = "client recv", .parent = NULL, .child = child));
 503         ct->btrn[1] = btr_new_node(&(struct btr_node_description)
 504                 EMBRACE(.name = "client send", .parent = parent, .child = NULL));
 505
 506         ct->task = task_register(&(struct task_info) {
 507                 .name = "client",
 508                 .pre_monitor = client_pre_monitor,
 509                 .post_monitor = client_post_monitor,
 510                 .context = ct,
 511         }, s);
 512         return 1;
 513 err_out:
 514         close(ct->scc.fd);
 515         ct->scc.fd = -1;
 516         return ret;
 517 }
 518
 519 static void handle_help_flag(struct lls_parse_result *lpr)
 520 {
 521         char *help;
 522
 523         if (CLIENT_OPT_GIVEN(DETAILED_HELP, lpr))
 524                 help = lls_long_help(CLIENT_CMD_PTR);
 525         else if (CLIENT_OPT_GIVEN(HELP, lpr))
 526                 help = lls_short_help(CLIENT_CMD_PTR);
 527         else
 528                 return;
 529         printf("%s\n", help);
 530         free(help);
 531         exit(EXIT_SUCCESS);
 532 }
 533
 534 /**
 535  * Parse a client configuration.
 536  *
 537  * \param argc Usual argument count.
 538  * \param argv Usual argument vector.
 539  * \param ct_ptr Filled in by this function.
 540  * \param loglevel If not \p NULL, the number of the loglevel is stored here.
 541  *
 542  * This checks the command line options given by \a argc and \a argv, sets
 543  * default values for the user name and the name of the rsa key file and reads
 544  * further options from the config file.
 545  *
 546  * Upon successful return, \a ct_ptr points to a dynamically allocated and
 547  * initialized client task struct.
 548  *
 549  * \return The number of non-option arguments in \a argc/argv on success,
 550  * negative on errors.
 551  */
 552 int client_parse_config(int argc, char *argv[], struct client_task **ct_ptr,
 553                 int *loglevel)
 554 {
 555         const struct lls_command *cmd = CLIENT_CMD_PTR;
 556         struct lls_parse_result *lpr;
 557         int ret, ll;
 558         struct client_task *ct;
 559         char *kf = NULL, *user, *errctx, *home = para_homedir();
 560
 561         ret = lls(lls_parse(argc, argv, cmd, &lpr, &errctx));
 562         if (ret < 0)
 563                 goto out;
 564         version_handle_flag("client", CLIENT_OPT_GIVEN(VERSION, lpr));
 565         handle_help_flag(lpr);
 566
 567         ret = lsu_merge_config_file_options(CLIENT_OPT_STRING_VAL(CONFIG_FILE, lpr),
 568                 "client.conf", &lpr, cmd, client_suite, 0U /* default flags */);
 569         if (ret < 0)
 570                 goto out;
 571         /* success */
 572         ll = CLIENT_OPT_UINT32_VAL(LOGLEVEL, lpr);
 573         if (loglevel)
 574                 *loglevel = ll;
 575         user = CLIENT_OPT_GIVEN(USER, lpr)?
 576                 para_strdup(CLIENT_OPT_STRING_VAL(USER, lpr)) : para_logname();
 577
 578         if (CLIENT_OPT_GIVEN(KEY_FILE, lpr))
 579                 kf = para_strdup(CLIENT_OPT_STRING_VAL(KEY_FILE, lpr));
 580         else {
 581                 kf = make_message("%s/.paraslash/key.%s", home, user);
 582                 if (!file_exists(kf)) {
 583                         free(kf);
 584                         kf = make_message("%s/.ssh/id_rsa", home);
 585                 }
 586         }
 587         PARA_INFO_LOG("user: %s\n", user);
 588         PARA_INFO_LOG("key file: %s\n", kf);
 589         PARA_INFO_LOG("loglevel: %d\n", ll);
 590         ct = zalloc(sizeof(*ct));
 591         ct->scc.fd = -1;
 592         ct->lpr = lpr;
 593         ct->key_file = kf;
 594         ct->user = user;
 595         *ct_ptr = ct;
 596         ret = lls_num_inputs(lpr);
 597 out:
 598         free(home);
 599         if (ret < 0) {
 600                 if (errctx)
 601                         PARA_ERROR_LOG("%s\n", errctx);
 602                 free(errctx);
 603                 lls_free_parse_result(lpr, cmd);
 604                 free(kf);
 605                 *ct_ptr = NULL;
 606         }
 607         return ret;
 608 }
 609
 610 /**
 611  * Parse the client configuration and open a connection to para_server.
 612  *
 613  * \param argc See \ref client_parse_config.
 614  * \param argv See \ref client_parse_config.
 615  * \param ct_ptr See \ref client_parse_config.
 616  * \param loglevel See \ref client_parse_config.
 617  * \param parent See \ref client_connect().
 618  * \param child See \ref client_connect().
 619  * \param sched See \ref client_connect().
 620  *
 621  * This function combines client_parse_config() and client_connect(). It is
 622  * considered a syntax error if no command was given, i.e. if the number
 623  * of non-option arguments is zero.
 624  *
 625  * \return Standard.
 626  */
 627 int client_open(int argc, char *argv[], struct client_task **ct_ptr,
 628                 int *loglevel, struct btr_node *parent, struct btr_node *child,
 629                 struct sched *sched)
 630 {
 631         int ret = client_parse_config(argc, argv, ct_ptr, loglevel);
 632
 633         if (ret < 0)
 634                 return ret;
 635         if (ret == 0) {
 636                 ret = -E_CLIENT_SYNTAX;
 637                 goto fail;
 638         }
 639         ret = client_connect(*ct_ptr, sched, parent, child);
 640         if (ret < 0)
 641                 goto fail;
 642         return 1;
 643 fail:
 644         client_close(*ct_ptr);
 645         *ct_ptr = NULL;
 646         return ret;
 647 }