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_select(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                 para_fd_set(ct->scc.fd, &s->rfds, &s->max_fileno);
  72                 return;
  73
  74         case CL_RECEIVED_WELCOME:
  75         case CL_RECEIVED_PROCEED:
  76         case CL_RECEIVED_CHALLENGE:
  77                 para_fd_set(ct->scc.fd, &s->wfds, &s->max_fileno);
  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                                 para_fd_set(ct->scc.fd, &s->wfds, &s->max_fileno);
  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                                 para_fd_set(ct->scc.fd, &s->rfds, &s->max_fileno);
  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, fd_set *rfds,
 129                 struct sb_buffer *result)
 130 {
 131         int ret;
 132         size_t n;
 133         sb_transformation trafo;
 134         void *trafo_context;
 135         struct iovec iov;
 136
 137         if (!FD_ISSET(ct->scc.fd, rfds))
 138                 return 0;
 139         if (ct->status < CL_SENT_CH_RESPONSE)
 140                 trafo = trafo_context = NULL;
 141         else {
 142                 trafo = sc_trafo;
 143                 trafo_context = ct->scc.recv;
 144         }
 145         if (!ct->sbc[0])
 146                 ct->sbc[0] = sb_new_recv(0, trafo, trafo_context);
 147 again:
 148         sb_get_recv_buffer(ct->sbc[0], &iov);
 149         ret = read_nonblock(ct->scc.fd, iov.iov_base, iov.iov_len, rfds, &n);
 150         if (ret < 0) {
 151                 sb_free(ct->sbc[0]);
 152                 ct->sbc[0] = NULL;
 153                 return ret;
 154         }
 155         if (n == 0)
 156                 return 0;
 157         ret = sb_received(ct->sbc[0], n, result);
 158         if (ret < 0)
 159                 return ret;
 160         if (ret == 0)
 161                 goto again;
 162         ct->sbc[0] = NULL;
 163         return 1;
 164 }
 165
 166
 167 static char **parse_features(char *buf)
 168 {
 169         int i;
 170         const char id[] = "\nFeatures: ";
 171         char *p, *q, **features;
 172
 173         p = strstr(buf, id);
 174         if (!p)
 175                 return NULL;
 176         p += strlen(id);
 177         q = strchr(p, '\n');
 178         if (!q)
 179                 return NULL;
 180         *q = '\0';
 181         create_argv(p, ",", &features);
 182         for (i = 0; features[i]; i++)
 183                 PARA_INFO_LOG("server feature: %s\n", features[i]);
 184         return features;
 185 }
 186
 187 static int dispatch_sbb(struct client_task *ct, struct sb_buffer *sbb)
 188 {
 189         int ret;
 190         const char *designator[] = {SB_DESIGNATORS_ARRAY};
 191
 192         if (!sbb)
 193                 return 0;
 194         if (sbb->band < NUM_SB_DESIGNATORS)
 195                 PARA_DEBUG_LOG("band: %s\n", designator[sbb->band]);
 196
 197         switch (sbb->band) {
 198         case SBD_AWAITING_DATA:
 199                 ct->status = CL_SENDING;
 200                 ret = 1;
 201                 goto out;
 202         case SBD_OUTPUT:
 203                 if (iov_valid(&sbb->iov))
 204                         btr_add_output(sbb->iov.iov_base, sbb->iov.iov_len,
 205                                 ct->btrn[0]);
 206                 ret = 1;
 207                 goto out;
 208         case SBD_DEBUG_LOG:
 209         case SBD_INFO_LOG:
 210         case SBD_NOTICE_LOG:
 211         case SBD_WARNING_LOG:
 212         case SBD_ERROR_LOG:
 213         case SBD_CRIT_LOG:
 214         case SBD_EMERG_LOG:
 215                 if (iov_valid(&sbb->iov)) {
 216                         int ll = sbb->band - SBD_DEBUG_LOG;
 217                         para_log(ll, "remote: %s", (char *)sbb->iov.iov_base);
 218                 }
 219                 ret = 1;
 220                 goto deallocate;
 221         case SBD_EXIT__SUCCESS:
 222                 ret = -E_SERVER_CMD_SUCCESS;
 223                 goto deallocate;
 224         case SBD_EXIT__FAILURE:
 225                 ret = -E_SERVER_CMD_FAILURE;
 226                 goto deallocate;
 227         default:
 228                 PARA_ERROR_LOG("invalid band %d\n", sbb->band);
 229                 ret = -E_BAD_BAND;
 230                 goto deallocate;
 231         }
 232 deallocate:
 233         free(sbb->iov.iov_base);
 234 out:
 235         sbb->iov.iov_base = NULL;
 236         return ret;
 237 }
 238
 239 static int send_sb_command(struct client_task *ct)
 240 {
 241         int i;
 242         char *command, *p;
 243         size_t len = 0;
 244         unsigned num_inputs = lls_num_inputs(ct->lpr);
 245
 246         if (ct->sbc[1])
 247                 return send_sb(ct, 0, NULL, 0, 0, false);
 248
 249         for (i = 0; i < num_inputs; i++)
 250                 len += strlen(lls_input(i, ct->lpr)) + 1;
 251         p = command = para_malloc(len);
 252         for (i = 0; i < num_inputs; i++) {
 253                 const char *str = lls_input(i, ct->lpr);
 254                 strcpy(p, str);
 255                 p += strlen(str) + 1;
 256         }
 257         PARA_DEBUG_LOG("--> %s\n", command);
 258         return send_sb(ct, 0, command, len, SBD_COMMAND, false);
 259 }
 260
 261 /*
 262  * This function reads or writes to the socket file descriptor which
 263  * corresponds to an established connection between the client and the server.
 264  * It depends on the current state of the connection and on the readiness of
 265  * the socket file descriptor which type of I/O is going to be performed.
 266  * Besides the initial handshake and authentication, the function sends the
 267  * server command and receives the output from the server, if any.
 268  *
 269  * The context pointer refers to a client task structure that was initialized
 270  * earlier by client_open().
 271  */
 272 static int client_post_select(struct sched *s, void *context)
 273 {
 274         struct client_task *ct = context;
 275         int ret = 0;
 276         size_t n;
 277         char buf[CLIENT_BUFSIZE];
 278
 279         ret = task_get_notification(ct->task);
 280         if (ret < 0)
 281                 goto out;
 282         if (ct->scc.fd < 0)
 283                 return 0;
 284         switch (ct->status) {
 285         case CL_CONNECTED: /* receive welcome message */
 286                 ret = read_nonblock(ct->scc.fd, buf, sizeof(buf), &s->rfds, &n);
 287                 if (ret < 0 || n == 0)
 288                         goto out;
 289                 ct->features = parse_features(buf);
 290                 ct->status = CL_RECEIVED_WELCOME;
 291                 return 0;
 292         case CL_RECEIVED_WELCOME: /* send auth command */
 293                 if (!FD_ISSET(ct->scc.fd, &s->wfds))
 294                         return 0;
 295                 sprintf(buf, AUTH_REQUEST_MSG "%s", ct->user);
 296                 PARA_INFO_LOG("--> %s\n", buf);
 297                 ret = write_buffer(ct->scc.fd, buf);
 298                 if (ret < 0)
 299                         goto out;
 300                 ct->status = CL_SENT_AUTH;
 301                 return 0;
 302         case CL_SENT_AUTH:
 303                 /*
 304                  * Receive challenge and session keys, decrypt the challenge and
 305                  * send back the hash of the decrypted challenge.
 306                  */
 307                 {
 308                 /* decrypted challenge/session key buffer */
 309                 unsigned char crypt_buf[1024];
 310                 struct sb_buffer sbb;
 311
 312                 ret = recv_sb(ct, &s->rfds, &sbb);
 313                 if (ret <= 0)
 314                         goto out;
 315                 if (sbb.band != SBD_CHALLENGE) {
 316                         ret = -E_BAD_BAND;
 317                         free(sbb.iov.iov_base);
 318                                 goto out;
 319                 }
 320                 n = sbb.iov.iov_len;
 321                 PARA_INFO_LOG("<-- [challenge] (%zu bytes)\n", n);
 322                 ret = apc_priv_decrypt(ct->key_file, crypt_buf,
 323                         sbb.iov.iov_base, n);
 324                 free(sbb.iov.iov_base);
 325                 if (ret < 0)
 326                         goto out;
 327                 ct->challenge_hash = para_malloc(HASH_SIZE);
 328                 hash_function((char *)crypt_buf, APC_CHALLENGE_SIZE, ct->challenge_hash);
 329                 ct->scc.send = sc_new(crypt_buf + APC_CHALLENGE_SIZE, SESSION_KEY_LEN);
 330                 ct->scc.recv = sc_new(crypt_buf + APC_CHALLENGE_SIZE + SESSION_KEY_LEN,
 331                         SESSION_KEY_LEN);
 332                 hash_to_asc(ct->challenge_hash, buf);
 333                 PARA_INFO_LOG("--> %s\n", buf);
 334                 ct->status = CL_RECEIVED_CHALLENGE;
 335                 return 0;
 336                 }
 337         case CL_RECEIVED_CHALLENGE:
 338                 ret = send_sb(ct, 0, ct->challenge_hash, HASH_SIZE,
 339                         SBD_CHALLENGE_RESPONSE, false);
 340                 if (ret != 0)
 341                         ct->challenge_hash = NULL;
 342                 if (ret <= 0)
 343                         goto out;
 344                 ct->status = CL_SENT_CH_RESPONSE;
 345                 goto out;
 346         case CL_SENT_CH_RESPONSE: /* read server response */
 347                 {
 348                 struct sb_buffer sbb;
 349                 ret = recv_sb(ct, &s->rfds, &sbb);
 350                 if (ret <= 0)
 351                         goto out;
 352                 free(sbb.iov.iov_base);
 353                 if (sbb.band != SBD_PROCEED)
 354                         ret = -E_BAD_BAND;
 355                 else
 356                         ct->status = CL_RECEIVED_PROCEED;
 357                 goto out;
 358                 }
 359         case CL_RECEIVED_PROCEED: /* concat args and send command */
 360                 {
 361                 if (!FD_ISSET(ct->scc.fd, &s->wfds))
 362                         return 0;
 363                 ret = send_sb_command(ct);
 364                 if (ret <= 0)
 365                         goto out;
 366                 ct->status = CL_EXECUTING;
 367                 return 0;
 368                 }
 369         case CL_SENDING:
 370                 if (ct->btrn[1]) {
 371                         char *buf2;
 372                         size_t sz;
 373                         ret = btr_node_status(ct->btrn[1], 0, BTR_NT_LEAF);
 374                         if (ret == -E_BTR_EOF) {
 375                                 /* empty blob data packet indicates EOF */
 376                                 PARA_INFO_LOG("blob sent\n");
 377                                 ret = send_sb(ct, 1, NULL, 0, SBD_BLOB_DATA, true);
 378                                 if (ret >= 0)
 379                                         ret = -E_BTR_EOF;
 380                         }
 381                         if (ret < 0)
 382                                 goto close1;
 383                         if (ret > 0 && FD_ISSET(ct->scc.fd, &s->wfds)) {
 384                                 sz = btr_next_buffer(ct->btrn[1], &buf2);
 385                                 assert(sz);
 386                                 ret = send_sb(ct, 1, buf2, sz, SBD_BLOB_DATA, true);
 387                                 if (ret < 0)
 388                                         goto close1;
 389                                 if (ret > 0)
 390                                         btr_consume(ct->btrn[1], sz);
 391                         }
 392                 }
 393                 __attribute__ ((fallthrough));
 394         case CL_EXECUTING:
 395                 if (ct->btrn[0]) {
 396                         ret = btr_node_status(ct->btrn[0], 0, BTR_NT_ROOT);
 397                         if (ret < 0)
 398                                 goto close0;
 399                         if (ret > 0 && FD_ISSET(ct->scc.fd, &s->rfds)) {
 400                                 struct sb_buffer sbb;
 401                                 ret = recv_sb(ct, &s->rfds, &sbb);
 402                                 if (ret < 0)
 403                                         goto close0;
 404                                 if (ret > 0) {
 405                                         ret = dispatch_sbb(ct, &sbb);
 406                                         if (ret < 0)
 407                                                 goto close0;
 408                                 }
 409                         }
 410                 }
 411                 ret = 0;
 412                 goto out;
 413         }
 414 close1:
 415         PARA_INFO_LOG("channel 1: %s\n", para_strerror(-ret));
 416         btr_remove_node(&ct->btrn[1]);
 417         if (ct->btrn[0])
 418                 return 0;
 419         goto out;
 420 close0:
 421         PARA_INFO_LOG("channel 0: %s\n", para_strerror(-ret));
 422         btr_remove_node(&ct->btrn[0]);
 423         if (ct->btrn[1] && ct->status == CL_SENDING)
 424                 return 0;
 425 out:
 426         if (ret >= 0)
 427                 return 0;
 428         btr_remove_node(&ct->btrn[0]);
 429         btr_remove_node(&ct->btrn[1]);
 430         if (ret != -E_SERVER_CMD_SUCCESS && ret != -E_SERVER_CMD_FAILURE)
 431                 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
 432         if (ct->scc.fd >= 0) {
 433                 close(ct->scc.fd);
 434                 ct->scc.fd = -1;
 435         }
 436         free_argv(ct->features);
 437         ct->features = NULL;
 438         sc_free(ct->scc.recv);
 439         ct->scc.recv = NULL;
 440         sc_free(ct->scc.send);
 441         ct->scc.send = NULL;
 442         return ret;
 443 }
 444
 445 /**
 446  * Connect to para_server and register the client task.
 447  *
 448  * \param ct The initialized client task structure.
 449  * \param s The scheduler instance to register the client task to.
 450  * \param parent The parent node of the client btr node.
 451  * \param child The child node of the client node.
 452  *
 453  * The client task structure given by \a ct  must be allocated and initialized
 454  * by \ref client_parse_config() before this function is called.
 455  *
 456  * \return Standard.
 457  */
 458 int client_connect(struct client_task *ct, struct sched *s,
 459                 struct btr_node *parent, struct btr_node *child)
 460 {
 461         int ret;
 462         const char *host = CLIENT_OPT_STRING_VAL(HOSTNAME, ct->lpr);
 463         uint32_t port = CLIENT_OPT_UINT32_VAL(SERVER_PORT, ct->lpr);
 464
 465         PARA_NOTICE_LOG("connecting %s:%u\n", host, port);
 466         ct->scc.fd = -1;
 467         ret = para_connect_simple(IPPROTO_TCP, host, port);
 468         if (ret < 0)
 469                 return ret;
 470         ct->scc.fd = ret;
 471         ret = mark_fd_nonblocking(ct->scc.fd);
 472         if (ret < 0)
 473                 goto err_out;
 474         ct->status = CL_CONNECTED;
 475         ct->btrn[0] = btr_new_node(&(struct btr_node_description)
 476                 EMBRACE(.name = "client recv", .parent = NULL, .child = child));
 477         ct->btrn[1] = btr_new_node(&(struct btr_node_description)
 478                 EMBRACE(.name = "client send", .parent = parent, .child = NULL));
 479
 480         ct->task = task_register(&(struct task_info) {
 481                 .name = "client",
 482                 .pre_select = client_pre_select,
 483                 .post_select = client_post_select,
 484                 .context = ct,
 485         }, s);
 486         return 1;
 487 err_out:
 488         close(ct->scc.fd);
 489         ct->scc.fd = -1;
 490         return ret;
 491 }
 492
 493 static void handle_help_flag(struct lls_parse_result *lpr)
 494 {
 495         char *help;
 496
 497         if (CLIENT_OPT_GIVEN(DETAILED_HELP, lpr))
 498                 help = lls_long_help(CLIENT_CMD_PTR);
 499         else if (CLIENT_OPT_GIVEN(HELP, lpr))
 500                 help = lls_short_help(CLIENT_CMD_PTR);
 501         else
 502                 return;
 503         printf("%s\n", help);
 504         free(help);
 505         exit(EXIT_SUCCESS);
 506 }
 507
 508 /**
 509  * Parse a client configuration.
 510  *
 511  * \param argc Usual argument count.
 512  * \param argv Usual argument vector.
 513  * \param ct_ptr Filled in by this function.
 514  * \param loglevel If not \p NULL, the number of the loglevel is stored here.
 515  *
 516  * This checks the command line options given by \a argc and \a argv, sets
 517  * default values for the user name and the name of the rsa key file and reads
 518  * further options from the config file.
 519  *
 520  * Upon successful return, \a ct_ptr points to a dynamically allocated and
 521  * initialized client task struct.
 522  *
 523  * \return The number of non-option arguments in \a argc/argv on success,
 524  * negative on errors.
 525  */
 526 int client_parse_config(int argc, char *argv[], struct client_task **ct_ptr,
 527                 int *loglevel)
 528 {
 529         const struct lls_command *cmd = CLIENT_CMD_PTR;
 530         struct lls_parse_result *lpr;
 531         int ret, ll;
 532         struct client_task *ct;
 533         char *kf = NULL, *user, *errctx, *home = para_homedir();
 534
 535         ret = lls(lls_parse(argc, argv, cmd, &lpr, &errctx));
 536         if (ret < 0)
 537                 goto out;
 538         version_handle_flag("client", CLIENT_OPT_GIVEN(VERSION, lpr));
 539         handle_help_flag(lpr);
 540
 541         ret = lsu_merge_config_file_options(CLIENT_OPT_STRING_VAL(CONFIG_FILE, lpr),
 542                 "client.conf", &lpr, cmd, client_suite, 0U /* default flags */);
 543         if (ret < 0)
 544                 goto out;
 545         /* success */
 546         ll = CLIENT_OPT_UINT32_VAL(LOGLEVEL, lpr);
 547         if (loglevel)
 548                 *loglevel = ll;
 549         user = CLIENT_OPT_GIVEN(USER, lpr)?
 550                 para_strdup(CLIENT_OPT_STRING_VAL(USER, lpr)) : para_logname();
 551
 552         if (CLIENT_OPT_GIVEN(KEY_FILE, lpr))
 553                 kf = para_strdup(CLIENT_OPT_STRING_VAL(KEY_FILE, lpr));
 554         else {
 555                 kf = make_message("%s/.paraslash/key.%s", home, user);
 556                 if (!file_exists(kf)) {
 557                         free(kf);
 558                         kf = make_message("%s/.ssh/id_rsa", home);
 559                 }
 560         }
 561         PARA_INFO_LOG("user: %s\n", user);
 562         PARA_INFO_LOG("key file: %s\n", kf);
 563         PARA_INFO_LOG("loglevel: %d\n", ll);
 564         ct = para_calloc(sizeof(*ct));
 565         ct->scc.fd = -1;
 566         ct->lpr = lpr;
 567         ct->key_file = kf;
 568         ct->user = user;
 569         *ct_ptr = ct;
 570         ret = lls_num_inputs(lpr);
 571 out:
 572         free(home);
 573         if (ret < 0) {
 574                 if (errctx)
 575                         PARA_ERROR_LOG("%s\n", errctx);
 576                 free(errctx);
 577                 lls_free_parse_result(lpr, cmd);
 578                 free(kf);
 579                 *ct_ptr = NULL;
 580         }
 581         return ret;
 582 }
 583
 584 /**
 585  * Parse the client configuration and open a connection to para_server.
 586  *
 587  * \param argc See \ref client_parse_config.
 588  * \param argv See \ref client_parse_config.
 589  * \param ct_ptr See \ref client_parse_config.
 590  * \param loglevel See \ref client_parse_config.
 591  * \param parent See \ref client_connect().
 592  * \param child See \ref client_connect().
 593  * \param sched See \ref client_connect().
 594  *
 595  * This function combines client_parse_config() and client_connect(). It is
 596  * considered a syntax error if no command was given, i.e. if the number
 597  * of non-option arguments is zero.
 598  *
 599  * \return Standard.
 600  */
 601 int client_open(int argc, char *argv[], struct client_task **ct_ptr,
 602                 int *loglevel, struct btr_node *parent, struct btr_node *child,
 603                 struct sched *sched)
 604 {
 605         int ret = client_parse_config(argc, argv, ct_ptr, loglevel);
 606
 607         if (ret < 0)
 608                 return ret;
 609         if (ret == 0) {
 610                 ret = -E_CLIENT_SYNTAX;
 611                 goto fail;
 612         }
 613         ret = client_connect(*ct_ptr, sched, parent, child);
 614         if (ret < 0)
 615                 goto fail;
 616         return 1;
 617 fail:
 618         client_close(*ct_ptr);
 619         *ct_ptr = NULL;
 620         return ret;
 621 }