client_common.c

   1 /*
   2  * Copyright (C) 1997 Andre Noll <maan@tuebingen.mpg.de>
   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 free all resources.
  37  *
  38  * \param ct Pointer to the client data.
  39  *
  40  * \sa \ref client_open().
  41  */
  42 void client_close(struct client_task *ct)
  43 {
  44         if (!ct)
  45                 return;
  46         free(ct->user);
  47         free(ct->config_file);
  48         free(ct->key_file);
  49         client_cmdline_parser_free(&ct->conf);
  50         free(ct->challenge_hash);
  51         sb_free(ct->sbc[0]);
  52         sb_free(ct->sbc[1]);
  53         free(ct);
  54 }
  55
  56 /*
  57  * The preselect hook for server commands.
  58  *
  59  * The task pointer must contain a pointer to the initialized client data
  60  * structure as it is returned by client_open().
  61  *
  62  * This function checks the state of the connection and adds the file descriptor
  63  * of the connection to the read or write fd set of s accordingly.
  64  */
  65 static void client_pre_select(struct sched *s, void *context)
  66 {
  67         int ret;
  68         struct client_task *ct = context;
  69
  70         if (ct->scc.fd < 0)
  71                 return;
  72         switch (ct->status) {
  73         case CL_CONNECTED:
  74         case CL_SENT_AUTH:
  75         case CL_SENT_CH_RESPONSE:
  76                 para_fd_set(ct->scc.fd, &s->rfds, &s->max_fileno);
  77                 return;
  78
  79         case CL_RECEIVED_WELCOME:
  80         case CL_RECEIVED_PROCEED:
  81         case CL_RECEIVED_CHALLENGE:
  82                 para_fd_set(ct->scc.fd, &s->wfds, &s->max_fileno);
  83                 return;
  84
  85         case CL_SENDING:
  86                 if (ct->btrn[1]) {
  87                         ret = btr_node_status(ct->btrn[1], 0, BTR_NT_LEAF);
  88                         if (ret < 0)
  89                                 sched_min_delay(s);
  90                         else if (ret > 0)
  91                                 para_fd_set(ct->scc.fd, &s->wfds, &s->max_fileno);
  92                 }
  93                 /* fall though */
  94         case CL_EXECUTING:
  95                 if (ct->btrn[0]) {
  96                         ret = btr_node_status(ct->btrn[0], 0, BTR_NT_ROOT);
  97                         if (ret < 0)
  98                                 sched_min_delay(s);
  99                         else if (ret > 0)
 100                                 para_fd_set(ct->scc.fd, &s->rfds, &s->max_fileno);
 101                 }
 102                 return;
 103         }
 104 }
 105
 106 static int send_sb(struct client_task *ct, int channel, void *buf, size_t numbytes,
 107                 enum sb_designator band, bool dont_free)
 108 {
 109         int ret, fd = ct->scc.fd;
 110         struct iovec iov[2];
 111
 112         if (!ct->sbc[channel]) {
 113                 struct sb_buffer sbb;
 114                 sb_transformation trafo = ct->status < CL_RECEIVED_PROCEED?
 115                         NULL : sc_trafo;
 116                 sbb = (typeof(sbb))SBB_INIT(band, buf, numbytes);
 117                 ct->sbc[channel] = sb_new_send(&sbb, dont_free, trafo, ct->scc.send);
 118         }
 119         ret = sb_get_send_buffers(ct->sbc[channel], iov);
 120         ret = xwritev(fd, iov, ret);
 121         if (ret < 0) {
 122                 sb_free(ct->sbc[channel]);
 123                 ct->sbc[channel] = NULL;
 124                 return ret;
 125         }
 126         if (sb_sent(ct->sbc[channel], ret)) {
 127                 ct->sbc[channel] = NULL;
 128                 return 1;
 129         }
 130         return 0;
 131 }
 132
 133 static int recv_sb(struct client_task *ct, fd_set *rfds,
 134                 struct sb_buffer *result)
 135 {
 136         int ret;
 137         size_t n;
 138         sb_transformation trafo;
 139         void *trafo_context;
 140         struct iovec iov;
 141
 142         if (!FD_ISSET(ct->scc.fd, rfds))
 143                 return 0;
 144         if (ct->status < CL_SENT_CH_RESPONSE)
 145                 trafo = trafo_context = NULL;
 146         else {
 147                 trafo = sc_trafo;
 148                 trafo_context = ct->scc.recv;
 149         }
 150         if (!ct->sbc[0])
 151                 ct->sbc[0] = sb_new_recv(0, trafo, trafo_context);
 152 again:
 153         sb_get_recv_buffer(ct->sbc[0], &iov);
 154         ret = read_nonblock(ct->scc.fd, iov.iov_base, iov.iov_len, rfds, &n);
 155         if (ret < 0) {
 156                 sb_free(ct->sbc[0]);
 157                 ct->sbc[0] = NULL;
 158                 return ret;
 159         }
 160         if (n == 0)
 161                 return 0;
 162         ret = sb_received(ct->sbc[0], n, result);
 163         if (ret < 0)
 164                 return ret;
 165         if (ret == 0)
 166                 goto again;
 167         ct->sbc[0] = NULL;
 168         return 1;
 169 }
 170
 171
 172 static char **parse_features(char *buf)
 173 {
 174         int i;
 175         const char id[] = "\nFeatures: ";
 176         char *p, *q, **features;
 177
 178         p = strstr(buf, id);
 179         if (!p)
 180                 return NULL;
 181         p += strlen(id);
 182         q = strchr(p, '\n');
 183         if (!q)
 184                 return NULL;
 185         *q = '\0';
 186         create_argv(p, ",", &features);
 187         for (i = 0; features[i]; i++)
 188                 PARA_INFO_LOG("server feature: %s\n", features[i]);
 189         return features;
 190 }
 191
 192 static int dispatch_sbb(struct client_task *ct, struct sb_buffer *sbb)
 193 {
 194         int ret;
 195         const char *designator[] = {SB_DESIGNATORS_ARRAY};
 196
 197         if (!sbb)
 198                 return 0;
 199         if (sbb->band < NUM_SB_DESIGNATORS)
 200                 PARA_DEBUG_LOG("band: %s\n", designator[sbb->band]);
 201
 202         switch (sbb->band) {
 203         case SBD_AWAITING_DATA:
 204                 ct->status = CL_SENDING;
 205                 ret = 1;
 206                 goto out;
 207         case SBD_OUTPUT:
 208                 if (iov_valid(&sbb->iov))
 209                         btr_add_output(sbb->iov.iov_base, sbb->iov.iov_len,
 210                                 ct->btrn[0]);
 211                 ret = 1;
 212                 goto out;
 213         case SBD_DEBUG_LOG:
 214         case SBD_INFO_LOG:
 215         case SBD_NOTICE_LOG:
 216         case SBD_WARNING_LOG:
 217         case SBD_ERROR_LOG:
 218         case SBD_CRIT_LOG:
 219         case SBD_EMERG_LOG:
 220                 if (iov_valid(&sbb->iov)) {
 221                         int ll = sbb->band - SBD_DEBUG_LOG;
 222                         para_log(ll, "remote: %s", (char *)sbb->iov.iov_base);
 223                 }
 224                 ret = 1;
 225                 goto deallocate;
 226         case SBD_EXIT__SUCCESS:
 227                 ret = -E_SERVER_CMD_SUCCESS;
 228                 goto deallocate;
 229         case SBD_EXIT__FAILURE:
 230                 ret = -E_SERVER_CMD_FAILURE;
 231                 goto deallocate;
 232         default:
 233                 PARA_ERROR_LOG("invalid band %d\n", sbb->band);
 234                 ret = -E_BAD_BAND;
 235                 goto deallocate;
 236         }
 237 deallocate:
 238         free(sbb->iov.iov_base);
 239 out:
 240         sbb->iov.iov_base = NULL;
 241         return ret;
 242 }
 243
 244 static bool has_feature(const char *feature, struct client_task *ct)
 245 {
 246         return find_arg(feature, ct->features) >= 0? true : false;
 247 }
 248
 249 static int send_sb_command(struct client_task *ct)
 250 {
 251         int i;
 252         char *command, *p;
 253         size_t len = 0;
 254
 255         if (ct->sbc[1])
 256                 return send_sb(ct, 0, NULL, 0, 0, false);
 257
 258         for (i = 0; i < ct->conf.inputs_num; i++)
 259                 len += strlen(ct->conf.inputs[i]) + 1;
 260         p = command = para_malloc(len);
 261         for (i = 0; i < ct->conf.inputs_num; i++) {
 262                 strcpy(p, ct->conf.inputs[i]);
 263                 p += strlen(ct->conf.inputs[i]) + 1;
 264         }
 265         PARA_DEBUG_LOG("--> %s\n", command);
 266         return send_sb(ct, 0, command, len, SBD_COMMAND, false);
 267 }
 268
 269 /*
 270  * The post select hook for client commands.
 271  *
 272  * Depending on the current state of the connection and the status of the read
 273  * and write fd sets of s, this function performs the necessary steps to
 274  * authenticate the connection, to send the command given by t->private_data
 275  * and to receive para_server's output, if any.
 276  */
 277 static int client_post_select(struct sched *s, void *context)
 278 {
 279         struct client_task *ct = context;
 280         int ret = 0;
 281         size_t n;
 282         char buf[CLIENT_BUFSIZE];
 283
 284         ret = task_get_notification(ct->task);
 285         if (ret < 0)
 286                 goto out;
 287         if (ct->scc.fd < 0)
 288                 return 0;
 289         switch (ct->status) {
 290         case CL_CONNECTED: /* receive welcome message */
 291                 ret = read_nonblock(ct->scc.fd, buf, sizeof(buf), &s->rfds, &n);
 292                 if (ret < 0 || n == 0)
 293                         goto out;
 294                 ct->features = parse_features(buf);
 295                 if (!has_feature("sideband", ct)) {
 296                         PARA_ERROR_LOG("server has no sideband support\n");
 297                         ret = -E_INCOMPAT_FEAT;
 298                         goto out;
 299                 }
 300                 ct->status = CL_RECEIVED_WELCOME;
 301                 return 0;
 302         case CL_RECEIVED_WELCOME: /* send auth command */
 303                 if (!FD_ISSET(ct->scc.fd, &s->wfds))
 304                         return 0;
 305                 sprintf(buf, AUTH_REQUEST_MSG "%s sideband%s", ct->user,
 306                         has_feature("aes_ctr128", ct)? ",aes_ctr128" : "");
 307                 PARA_INFO_LOG("--> %s\n", buf);
 308                 ret = write_buffer(ct->scc.fd, buf);
 309                 if (ret < 0)
 310                         goto out;
 311                 ct->status = CL_SENT_AUTH;
 312                 return 0;
 313         case CL_SENT_AUTH:
 314                 /*
 315                  * Receive challenge and session keys, decrypt the challenge and
 316                  * send back the hash of the decrypted challenge.
 317                  */
 318                 {
 319                 /* decrypted challenge/session key buffer */
 320                 unsigned char crypt_buf[1024];
 321                 struct sb_buffer sbb;
 322                 bool use_aes;
 323
 324                 ret = recv_sb(ct, &s->rfds, &sbb);
 325                 if (ret <= 0)
 326                         goto out;
 327                 if (sbb.band != SBD_CHALLENGE) {
 328                         ret = -E_BAD_BAND;
 329                         free(sbb.iov.iov_base);
 330                                 goto out;
 331                 }
 332                 n = sbb.iov.iov_len;
 333                 PARA_INFO_LOG("<-- [challenge] (%zu bytes)\n", n);
 334                 ret = priv_decrypt(ct->key_file, crypt_buf,
 335                         sbb.iov.iov_base, n);
 336                 free(sbb.iov.iov_base);
 337                 if (ret < 0)
 338                         goto out;
 339                 ct->challenge_hash = para_malloc(HASH_SIZE);
 340                 hash_function((char *)crypt_buf, CHALLENGE_SIZE, ct->challenge_hash);
 341                 use_aes = has_feature("aes_ctr128", ct);
 342                 ct->scc.send = sc_new(crypt_buf + CHALLENGE_SIZE, SESSION_KEY_LEN, use_aes);
 343                 ct->scc.recv = sc_new(crypt_buf + CHALLENGE_SIZE + SESSION_KEY_LEN,
 344                         SESSION_KEY_LEN, use_aes);
 345                 hash_to_asc(ct->challenge_hash, buf);
 346                 PARA_INFO_LOG("--> %s\n", buf);
 347                 ct->status = CL_RECEIVED_CHALLENGE;
 348                 return 0;
 349                 }
 350         case CL_RECEIVED_CHALLENGE:
 351                 ret = send_sb(ct, 0, ct->challenge_hash, HASH_SIZE,
 352                         SBD_CHALLENGE_RESPONSE, false);
 353                 if (ret != 0)
 354                         ct->challenge_hash = NULL;
 355                 if (ret <= 0)
 356                         goto out;
 357                 ct->status = CL_SENT_CH_RESPONSE;
 358                 goto out;
 359         case CL_SENT_CH_RESPONSE: /* read server response */
 360                 {
 361                 struct sb_buffer sbb;
 362                 ret = recv_sb(ct, &s->rfds, &sbb);
 363                 if (ret <= 0)
 364                         goto out;
 365                 free(sbb.iov.iov_base);
 366                 if (sbb.band != SBD_PROCEED)
 367                         ret = -E_BAD_BAND;
 368                 else
 369                         ct->status = CL_RECEIVED_PROCEED;
 370                 goto out;
 371                 }
 372         case CL_RECEIVED_PROCEED: /* concat args and send command */
 373                 {
 374                 if (!FD_ISSET(ct->scc.fd, &s->wfds))
 375                         return 0;
 376                 ret = send_sb_command(ct);
 377                 if (ret <= 0)
 378                         goto out;
 379                 ct->status = CL_EXECUTING;
 380                 return 0;
 381                 }
 382         case CL_SENDING:
 383                 if (ct->btrn[1]) {
 384                         char *buf2;
 385                         size_t sz;
 386                         ret = btr_node_status(ct->btrn[1], 0, BTR_NT_LEAF);
 387                         if (ret == -E_BTR_EOF) {
 388                                 /* empty blob data packet indicates EOF */
 389                                 PARA_INFO_LOG("blob sent\n");
 390                                 ret = send_sb(ct, 1, NULL, 0, SBD_BLOB_DATA, true);
 391                                 if (ret >= 0)
 392                                         ret = -E_BTR_EOF;
 393                         }
 394                         if (ret < 0)
 395                                 goto close1;
 396                         if (ret > 0 && FD_ISSET(ct->scc.fd, &s->wfds)) {
 397                                 sz = btr_next_buffer(ct->btrn[1], &buf2);
 398                                 assert(sz);
 399                                 ret = send_sb(ct, 1, buf2, sz, SBD_BLOB_DATA, true);
 400                                 if (ret < 0)
 401                                         goto close1;
 402                                 if (ret > 0)
 403                                         btr_consume(ct->btrn[1], sz);
 404                         }
 405                 }
 406                 /* fall through */
 407         case CL_EXECUTING:
 408                 if (ct->btrn[0]) {
 409                         ret = btr_node_status(ct->btrn[0], 0, BTR_NT_ROOT);
 410                         if (ret < 0)
 411                                 goto close0;
 412                         if (ret > 0 && FD_ISSET(ct->scc.fd, &s->rfds)) {
 413                                 struct sb_buffer sbb;
 414                                 ret = recv_sb(ct, &s->rfds, &sbb);
 415                                 if (ret < 0)
 416                                         goto close0;
 417                                 if (ret > 0) {
 418                                         ret = dispatch_sbb(ct, &sbb);
 419                                         if (ret < 0)
 420                                                 goto close0;
 421                                 }
 422                         }
 423                 }
 424                 ret = 0;
 425                 goto out;
 426         }
 427 close1:
 428         PARA_INFO_LOG("channel 1: %s\n", para_strerror(-ret));
 429         btr_remove_node(&ct->btrn[1]);
 430         if (ct->btrn[0])
 431                 return 0;
 432         goto out;
 433 close0:
 434         PARA_INFO_LOG("channel 0: %s\n", para_strerror(-ret));
 435         btr_remove_node(&ct->btrn[0]);
 436         if (ct->btrn[1] && ct->status == CL_SENDING)
 437                 return 0;
 438 out:
 439         if (ret >= 0)
 440                 return 0;
 441         btr_remove_node(&ct->btrn[0]);
 442         btr_remove_node(&ct->btrn[1]);
 443         if (ret != -E_SERVER_CMD_SUCCESS && ret != -E_SERVER_CMD_FAILURE)
 444                 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
 445         if (ct->scc.fd >= 0) {
 446                 close(ct->scc.fd);
 447                 ct->scc.fd = -1;
 448         }
 449         free_argv(ct->features);
 450         ct->features = NULL;
 451         sc_free(ct->scc.recv);
 452         ct->scc.recv = NULL;
 453         sc_free(ct->scc.send);
 454         ct->scc.send = NULL;
 455         return ret;
 456 }
 457
 458 /**
 459  * Connect to para_server and register the client task.
 460  *
 461  * \param ct The initialized client task structure.
 462  * \param s The scheduler instance to register the client task to.
 463  * \param parent The parent node of the client btr node.
 464  * \param child The child node of the client node.
 465  *
 466  * The client task structure given by \a ct  must be allocated and initialized
 467  * by \ref client_parse_config() before this function is called.
 468  *
 469  * \return Standard.
 470  */
 471 int client_connect(struct client_task *ct, struct sched *s,
 472                 struct btr_node *parent, struct btr_node *child)
 473 {
 474         int ret;
 475
 476         PARA_NOTICE_LOG("connecting %s:%d\n", ct->conf.hostname_arg,
 477                 ct->conf.server_port_arg);
 478         ct->scc.fd = -1;
 479         ret = para_connect_simple(IPPROTO_TCP, ct->conf.hostname_arg,
 480                                                ct->conf.server_port_arg);
 481         if (ret < 0)
 482                 return ret;
 483         ct->scc.fd = ret;
 484         ret = mark_fd_nonblocking(ct->scc.fd);
 485         if (ret < 0)
 486                 goto err_out;
 487         ct->status = CL_CONNECTED;
 488         ct->btrn[0] = btr_new_node(&(struct btr_node_description)
 489                 EMBRACE(.name = "client recv", .parent = NULL, .child = child));
 490         ct->btrn[1] = btr_new_node(&(struct btr_node_description)
 491                 EMBRACE(.name = "client send", .parent = parent, .child = NULL));
 492
 493         ct->task = task_register(&(struct task_info) {
 494                 .name = "client",
 495                 .pre_select = client_pre_select,
 496                 .post_select = client_post_select,
 497                 .context = ct,
 498         }, s);
 499         return 1;
 500 err_out:
 501         close(ct->scc.fd);
 502         ct->scc.fd = -1;
 503         return ret;
 504 }
 505
 506 __noreturn static void print_help_and_die(struct client_task *ct)
 507 {
 508         struct ggo_help h = DEFINE_GGO_HELP(client);
 509         bool d = ct->conf.detailed_help_given;
 510
 511         ggo_print_help(&h, d? GPH_STANDARD_FLAGS_DETAILED : GPH_STANDARD_FLAGS);
 512         exit(0);
 513 }
 514
 515 /**
 516  * Parse a client configuration.
 517  *
 518  * \param argc Usual argument count.
 519  * \param argv Usual argument vector.
 520  * \param ct_ptr Filled in by this function.
 521  * \param loglevel If not \p NULL, the number of the loglevel is stored here.
 522  *
 523  * This checks the command line options given by \a argc and \a argv, sets
 524  * default values for the user name and the name of the rsa key file and reads
 525  * further options from the config file.
 526  *
 527  * Upon successful return, \a ct_ptr points to a dynamically allocated and
 528  * initialized client task struct.
 529  *
 530  * \return The number of non-option arguments in \a argc/argv on success,
 531  * negative on errors.
 532  */
 533 int client_parse_config(int argc, char *argv[], struct client_task **ct_ptr,
 534                 int *loglevel)
 535 {
 536         char *home = para_homedir();
 537         int ret;
 538         struct client_task *ct = para_calloc(sizeof(struct client_task));
 539
 540         *ct_ptr = ct;
 541         ct->scc.fd = -1;
 542         ret = -E_CLIENT_SYNTAX;
 543         if (client_cmdline_parser(argc, argv, &ct->conf))
 544                 goto out;
 545         version_handle_flag("client", ct->conf.version_given);
 546         if (ct->conf.help_given || ct->conf.detailed_help_given)
 547                 print_help_and_die(ct);
 548
 549         ct->config_file = ct->conf.config_file_given?
 550                 para_strdup(ct->conf.config_file_arg) :
 551                 make_message("%s/.paraslash/client.conf", home);
 552         ret = file_exists(ct->config_file);
 553         if (!ret && ct->conf.config_file_given) {
 554                 ret = -E_NO_CONFIG;
 555                 goto out;
 556         }
 557         if (ret) {
 558                 struct client_cmdline_parser_params params = {
 559                         .override = 0,
 560                         .initialize = 0,
 561                         .check_required = 0,
 562                         .check_ambiguity = 0,
 563                         .print_errors = 0
 564                 };
 565                 ret = -E_BAD_CONFIG;
 566                 if (client_cmdline_parser_config_file(ct->config_file,
 567                         &ct->conf, &params))
 568                         goto out;
 569         }
 570         ct->user = ct->conf.user_given?
 571                 para_strdup(ct->conf.user_arg) : para_logname();
 572
 573         if (ct->conf.key_file_given)
 574                 ct->key_file = para_strdup(ct->conf.key_file_arg);
 575         else {
 576                 ct->key_file = make_message("%s/.paraslash/key.%s",
 577                         home, ct->user);
 578                 if (!file_exists(ct->key_file)) {
 579                         free(ct->key_file);
 580                         ct->key_file = make_message("%s/.ssh/id_rsa", home);
 581                 }
 582         }
 583
 584         if (loglevel)
 585                 *loglevel = get_loglevel_by_name(ct->conf.loglevel_arg);
 586         PARA_INFO_LOG("loglevel: %s\n", ct->conf.loglevel_arg);
 587         PARA_INFO_LOG("config_file: %s\n", ct->config_file);
 588         PARA_INFO_LOG("key_file: %s\n", ct->key_file);
 589         ret = ct->conf.inputs_num;
 590 out:
 591         free(home);
 592         if (ret < 0) {
 593                 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
 594                 client_close(ct);
 595                 *ct_ptr = NULL;
 596         }
 597         return ret;
 598 }
 599
 600 /**
 601  * Parse the client configuration and open a connection to para_server.
 602  *
 603  * \param argc See \ref client_parse_config.
 604  * \param argv See \ref client_parse_config.
 605  * \param ct_ptr See \ref client_parse_config.
 606  * \param loglevel See \ref client_parse_config.
 607  * \param parent See \ref client_connect().
 608  * \param child See \ref client_connect().
 609  * \param sched See \ref client_connect().
 610  *
 611  * This function combines client_parse_config() and client_connect(). It is
 612  * considered a syntax error if no command was given, i.e. if the number
 613  * of non-option arguments is zero.
 614  *
 615  * \return Standard.
 616  */
 617 int client_open(int argc, char *argv[], struct client_task **ct_ptr,
 618                 int *loglevel, struct btr_node *parent, struct btr_node *child,
 619                 struct sched *sched)
 620 {
 621         int ret = client_parse_config(argc, argv, ct_ptr, loglevel);
 622
 623         if (ret < 0)
 624                 return ret;
 625         if (ret == 0) {
 626                 ret = -E_CLIENT_SYNTAX;
 627                 goto fail;
 628         }
 629         ret = client_connect(*ct_ptr, sched, parent, child);
 630         if (ret < 0)
 631                 goto fail;
 632         return 1;
 633 fail:
 634         client_close(*ct_ptr);
 635         *ct_ptr = NULL;
 636         return ret;
 637 }