client_common.c

   1 /*
   2  * Copyright (C) 1997-2012 Andre Noll <maan@systemlinux.org>
   3  *
   4  * Licensed under the GPL v2. For licencing details see COPYING.
   5  */
   6
   7 /** \file client_common.c Common functions of para_client and para_audiod. */
   8
   9 #include <regex.h>
  10 #include <sys/types.h>
  11
  12 #include "para.h"
  13 #include "error.h"
  14 #include "list.h"
  15 #include "sched.h"
  16 #include "client.cmdline.h"
  17 #include "crypt.h"
  18 #include "net.h"
  19 #include "fd.h"
  20 #include "string.h"
  21 #include "client.cmdline.h"
  22 #include "client.h"
  23 #include "buffer_tree.h"
  24 #include "version.h"
  25
  26 /** The size of the receiving buffer. */
  27 #define CLIENT_BUFSIZE 4000
  28
  29 /**
  30  * Close the connection to para_server and deallocate per-command ressources.
  31  *
  32  * \param ct The client task.
  33  *
  34  * This frees all ressources of the current command but keeps the configuration
  35  * in \p ct->conf.
  36  *
  37  * \sa \ref client_close().
  38  */
  39 void client_disconnect(struct client_task *ct)
  40 {
  41         if (!ct)
  42                 return;
  43         if (ct->scc.fd >= 0)
  44                 close(ct->scc.fd);
  45         sc_free(ct->scc.recv);
  46         ct->scc.recv = NULL;
  47         sc_free(ct->scc.send);
  48         ct->scc.send = NULL;
  49         btr_free_node(ct->btrn);
  50         ct->btrn = NULL;
  51 }
  52
  53 /**
  54  * Close the connection to para_server and free all resources.
  55  *
  56  * \param ct Pointer to the client data.
  57  *
  58  * \sa \ref client_open(), \ref client_disconnect().
  59  */
  60 void client_close(struct client_task *ct)
  61 {
  62         if (!ct)
  63                 return;
  64         client_disconnect(ct);
  65         free(ct->user);
  66         free(ct->config_file);
  67         free(ct->key_file);
  68         client_cmdline_parser_free(&ct->conf);
  69         free(ct);
  70 }
  71
  72 /**
  73  * The preselect hook for server commands.
  74  *
  75  * \param s Pointer to the scheduler.
  76  * \param t Pointer to the task struct for this command.
  77  *
  78  * The task pointer must contain a pointer to the initialized client data
  79  * structure as it is returned by client_open().
  80  *
  81  * This function checks the state of the connection and adds the file descriptor
  82  * of the connection to the read or write fd set of \a s accordingly.
  83  *
  84  * \sa register_task() client_open(), struct sched, struct task.
  85  */
  86 static void client_pre_select(struct sched *s, struct task *t)
  87 {
  88         int ret;
  89         struct client_task *ct = container_of(t, struct client_task, task);
  90         struct btr_node *btrn = ct->btrn;
  91
  92         if (ct->scc.fd < 0)
  93                 return;
  94         switch (ct->status) {
  95         case CL_CONNECTED:
  96         case CL_SENT_AUTH:
  97         case CL_SENT_CH_RESPONSE:
  98         case CL_SENT_COMMAND:
  99                 para_fd_set(ct->scc.fd, &s->rfds, &s->max_fileno);
 100                 return;
 101
 102         case CL_RECEIVED_WELCOME:
 103         case CL_RECEIVED_PROCEED:
 104                 para_fd_set(ct->scc.fd, &s->wfds, &s->max_fileno);
 105                 return;
 106
 107         case CL_RECEIVING:
 108                 ret = btr_node_status(btrn, 0, BTR_NT_ROOT);
 109                 if (ret != 0) {
 110                         if (ret < 0)
 111                                 sched_min_delay(s);
 112                         else
 113                                 para_fd_set(ct->scc.fd, &s->rfds,
 114                                         &s->max_fileno);
 115                 }
 116                 return;
 117         case CL_SENDING:
 118                 ret = btr_node_status(btrn, 0, BTR_NT_LEAF);
 119                 if (ret != 0) {
 120                         if (ret < 0)
 121                                 sched_min_delay(s);
 122                         else
 123                                 para_fd_set(ct->scc.fd, &s->wfds,
 124                                         &s->max_fileno);
 125                 }
 126                 return;
 127         }
 128 }
 129
 130 static int client_recv_buffer(struct client_task *ct, fd_set *rfds,
 131                 char *buf, size_t sz, size_t *n)
 132 {
 133         int ret;
 134
 135         if (ct->status < CL_SENT_CH_RESPONSE)
 136                 return read_nonblock(ct->scc.fd, buf, sz, rfds, n);
 137
 138         *n = 0;
 139         ret = sc_recv_buffer(&ct->scc, buf, sz);
 140         /*
 141          * sc_recv_buffer is used with blocking fds elsewhere, so it
 142          * does not use the nonblock-API. Therefore we need to
 143          * check for EOF and EAGAIN.
 144          */
 145         if (ret == 0)
 146                 return -E_SERVER_EOF;
 147         if (ret == -ERRNO_TO_PARA_ERROR(EAGAIN))
 148                 return 0;
 149         if (ret < 0)
 150                 return ret;
 151         *n = ret;
 152         return 0;
 153 }
 154
 155 /**
 156  * The post select hook for client commands.
 157  *
 158  * \param s Pointer to the scheduler.
 159  * \param t Pointer to the task struct for this command.
 160  *
 161  * Depending on the current state of the connection and the status of the read
 162  * and write fd sets of \a s, this function performs the necessary steps to
 163  * authenticate the connection, to send the command given by \a t->private_data
 164  * and to receive para_server's output, if any.
 165  *
 166  * \sa struct sched, struct task.
 167  */
 168 static void client_post_select(struct sched *s, struct task *t)
 169 {
 170         struct client_task *ct = container_of(t, struct client_task, task);
 171         struct btr_node *btrn = ct->btrn;
 172         int ret = 0;
 173         size_t n;
 174         char buf[CLIENT_BUFSIZE];
 175
 176         t->error = 0;
 177         if (ct->scc.fd < 0)
 178                 return;
 179         switch (ct->status) {
 180         case CL_CONNECTED: /* receive welcome message */
 181                 ret = client_recv_buffer(ct, &s->rfds, buf, sizeof(buf), &n);
 182                 if (ret < 0 || n == 0)
 183                         goto out;
 184                 ct->status = CL_RECEIVED_WELCOME;
 185                 return;
 186         case CL_RECEIVED_WELCOME: /* send auth command */
 187                 sprintf(buf, AUTH_REQUEST_MSG "%s", ct->user);
 188                 PARA_INFO_LOG("--> %s\n", buf);
 189                 if (!FD_ISSET(ct->scc.fd, &s->wfds))
 190                         return;
 191                 ret = send_buffer(ct->scc.fd, buf);
 192                 if (ret < 0)
 193                         goto out;
 194                 ct->status = CL_SENT_AUTH;
 195                 return;
 196         case CL_SENT_AUTH:
 197                 /*
 198                  * Receive challenge and session keys, decrypt the challenge and
 199                  * send back the hash of the decrypted challenge.
 200                  */
 201                 {
 202                 /* decrypted challenge/session key buffer */
 203                 unsigned char crypt_buf[1024];
 204                 /* the SHA1 of the decrypted challenge */
 205                 unsigned char challenge_hash[HASH_SIZE];
 206
 207                 ret = client_recv_buffer(ct, &s->rfds, buf, sizeof(buf), &n);
 208                 if (ret < 0 || n == 0)
 209                         goto out;
 210                 PARA_INFO_LOG("<-- [challenge] (%zu bytes)\n", n);
 211                 ret = priv_decrypt(ct->key_file, crypt_buf,
 212                         (unsigned char *)buf, n);
 213                 if (ret < 0)
 214                         goto out;
 215                 hash_function((char *)crypt_buf, CHALLENGE_SIZE, challenge_hash);
 216                 ct->scc.send = sc_new(crypt_buf + CHALLENGE_SIZE, SESSION_KEY_LEN);
 217                 ct->scc.recv = sc_new(crypt_buf + CHALLENGE_SIZE + SESSION_KEY_LEN,
 218                         SESSION_KEY_LEN);
 219                 hash_to_asc(challenge_hash, buf);
 220                 PARA_INFO_LOG("--> %s\n", buf);
 221                 ret = send_bin_buffer(ct->scc.fd, (char *)challenge_hash,
 222                         HASH_SIZE);
 223                 if (ret < 0)
 224                         goto out;
 225                 ct->status = CL_SENT_CH_RESPONSE;
 226                 return;
 227                 }
 228         case CL_SENT_CH_RESPONSE: /* read server response */
 229                 {
 230                 ret = client_recv_buffer(ct, &s->rfds, buf, sizeof(buf), &n);
 231                 if (ret < 0 || n == 0)
 232                         goto out;
 233                 /* check if server has sent "Proceed" message */
 234                 ret = -E_CLIENT_AUTH;
 235                 if (n < PROCEED_MSG_LEN)
 236                         goto out;
 237                 if (!strstr(buf, PROCEED_MSG))
 238                         goto out;
 239                 ct->status = CL_RECEIVED_PROCEED;
 240                 return;
 241                 }
 242         case CL_RECEIVED_PROCEED: /* concat args and send command */
 243                 {
 244                 int i;
 245                 char *command = NULL;
 246                 if (!FD_ISSET(ct->scc.fd, &s->wfds))
 247                         return;
 248                 for (i = 0; i < ct->conf.inputs_num; i++) {
 249                         char *tmp = command;
 250                         command = make_message("%s\n%s", command?
 251                                 command : "", ct->conf.inputs[i]);
 252                         free(tmp);
 253                 }
 254                 command = para_strcat(command, EOC_MSG "\n");
 255                 PARA_DEBUG_LOG("--> %s\n", command);
 256                 ret = sc_send_buffer(&ct->scc, command);
 257                 free(command);
 258                 if (ret < 0)
 259                         goto out;
 260                 ct->status = CL_SENT_COMMAND;
 261                 return;
 262                 }
 263         case CL_SENT_COMMAND:
 264                 {
 265                 char *buf2;
 266                 /* can not use "buf" here because we need a malloced buffer */
 267                 buf2 = para_malloc(CLIENT_BUFSIZE);
 268                 ret = client_recv_buffer(ct, &s->rfds, buf2, CLIENT_BUFSIZE, &n);
 269                 if (n > 0) {
 270                         if (strstr(buf2, AWAITING_DATA_MSG)) {
 271                                 free(buf2);
 272                                 ct->status = CL_SENDING;
 273                                 return;
 274                         }
 275                         ct->status = CL_RECEIVING;
 276                         btr_add_output(buf2, n, btrn);
 277                 } else
 278                         free(buf2);
 279                 goto out;
 280                 }
 281         case CL_SENDING:
 282                 {
 283                 char *buf2;
 284                 size_t sz;
 285                 ret = btr_node_status(btrn, 0, BTR_NT_LEAF);
 286                 if (ret < 0)
 287                         goto out;
 288                 if (ret == 0)
 289                         return;
 290                 if (!FD_ISSET(ct->scc.fd, &s->wfds))
 291                         return;
 292                 sz = btr_next_buffer(btrn, &buf2);
 293                 ret = sc_send_bin_buffer(&ct->scc, buf2, sz);
 294                 if (ret < 0)
 295                         goto out;
 296                 btr_consume(btrn, sz);
 297                 return;
 298                 }
 299         case CL_RECEIVING:
 300                 {
 301                 char *buf2;
 302                 ret = btr_node_status(btrn, 0, BTR_NT_ROOT);
 303                 if (ret < 0)
 304                         goto out;
 305                 if (ret == 0)
 306                         return;
 307                 /*
 308                  * The FD_ISSET() is not strictly necessary, but is allows us
 309                  * to skip the malloc below if there is nothing to read anyway.
 310                  */
 311                 if (!FD_ISSET(ct->scc.fd, &s->rfds))
 312                         return;
 313                 buf2 = para_malloc(CLIENT_BUFSIZE);
 314                 ret = client_recv_buffer(ct, &s->rfds, buf2, CLIENT_BUFSIZE, &n);
 315                 if (n > 0) {
 316                         buf2 = para_realloc(buf2, n);
 317                         btr_add_output(buf2, n, btrn);
 318                 } else
 319                         free(buf2);
 320                 goto out;
 321                 }
 322         }
 323 out:
 324         t->error = ret;
 325         if (ret < 0) {
 326                 if (ret != -E_SERVER_EOF && ret != -E_BTR_EOF)
 327                         PARA_ERROR_LOG("%s\n", para_strerror(-t->error));
 328                 btr_remove_node(btrn);
 329         }
 330 }
 331
 332 /**
 333  * Connect to para_server and register the client task.
 334  *
 335  * \param ct The initialized client task structure.
 336  * \param s The scheduler instance to register the client task to.
 337  * \param parent The parent node of the client btr node.
 338  * \param child The child node of the client node.
 339  *
 340  * The client task structure given by \a ct  must be allocated and initialized
 341  * by \ref client_parse_config() before this function is called.
 342  *
 343  * \return Standard.
 344  */
 345 int client_connect(struct client_task *ct, struct sched *s,
 346                 struct btr_node *parent, struct btr_node *child)
 347 {
 348         int ret;
 349
 350         PARA_NOTICE_LOG("connecting %s:%d\n", ct->conf.hostname_arg,
 351                 ct->conf.server_port_arg);
 352         ct->scc.fd = -1;
 353         ret = para_connect_simple(IPPROTO_TCP, ct->conf.hostname_arg,
 354                                                ct->conf.server_port_arg);
 355         if (ret < 0)
 356                 return ret;
 357         ct->scc.fd = ret;
 358         ret = mark_fd_nonblocking(ct->scc.fd);
 359         if (ret < 0)
 360                 goto err_out;
 361         ct->status = CL_CONNECTED;
 362         ct->btrn = btr_new_node(&(struct btr_node_description)
 363                 EMBRACE(.name = "client", .parent = parent, .child = child));
 364         ct->task.pre_select = client_pre_select;
 365         ct->task.post_select = client_post_select;
 366         ct->task.error = 0;
 367         sprintf(ct->task.status, "client");
 368         register_task(s, &ct->task);
 369         return 1;
 370 err_out:
 371         close(ct->scc.fd);
 372         ct->scc.fd = -1;
 373         return ret;
 374 }
 375
 376 /**
 377  * Parse a client configuration.
 378  *
 379  * \param argc Usual argument count.
 380  * \param argv Usual argument vector.
 381  * \param ct_ptr Filled in by this function.
 382  * \param loglevel If not \p NULL, the number of the loglevel is stored here.
 383  *
 384  * This checks the command line options given by \a argc and \a argv, sets
 385  * default values for the user name and the name of the rsa key file and reads
 386  * further options from the config file.
 387  *
 388  * Upon successful return, \a ct_ptr points to a dynamically allocated and
 389  * initialized client task struct.
 390  *
 391  * \return The number of non-option arguments in \a argc/argv on success,
 392  * negative on errors.
 393  */
 394 int client_parse_config(int argc, char *argv[], struct client_task **ct_ptr,
 395                 int *loglevel)
 396 {
 397         char *home = para_homedir();
 398         int ret;
 399         struct client_task *ct = para_calloc(sizeof(struct client_task));
 400
 401         *ct_ptr = ct;
 402         ct->scc.fd = -1;
 403         ret = -E_CLIENT_SYNTAX;
 404         if (client_cmdline_parser(argc, argv, &ct->conf))
 405                 goto out;
 406         HANDLE_VERSION_FLAG("client", ct->conf);
 407
 408         ct->config_file = ct->conf.config_file_given?
 409                 para_strdup(ct->conf.config_file_arg) :
 410                 make_message("%s/.paraslash/client.conf", home);
 411         ret = file_exists(ct->config_file);
 412         if (!ret && ct->conf.config_file_given) {
 413                 ret = -E_NO_CONFIG;
 414                 goto out;
 415         }
 416         if (ret) {
 417                 struct client_cmdline_parser_params params = {
 418                         .override = 0,
 419                         .initialize = 0,
 420                         .check_required = 0,
 421                         .check_ambiguity = 0,
 422                         .print_errors = 0
 423                 };
 424                 ret = -E_BAD_CONFIG;
 425                 if (client_cmdline_parser_config_file(ct->config_file,
 426                         &ct->conf, &params))
 427                         goto out;
 428         }
 429         ct->user = ct->conf.user_given?
 430                 para_strdup(ct->conf.user_arg) : para_logname();
 431
 432         if (ct->conf.key_file_given)
 433                 ct->key_file = para_strdup(ct->conf.key_file_arg);
 434         else {
 435                 ct->key_file = make_message("%s/.paraslash/key.%s",
 436                         home, ct->user);
 437                 if (!file_exists(ct->key_file)) {
 438                         free(ct->key_file);
 439                         ct->key_file = make_message("%s/.ssh/id_rsa", home);
 440                 }
 441         }
 442
 443         if (loglevel)
 444                 *loglevel = get_loglevel_by_name(ct->conf.loglevel_arg);
 445         PARA_INFO_LOG("loglevel: %s\n", ct->conf.loglevel_arg);
 446         PARA_INFO_LOG("config_file: %s\n", ct->config_file);
 447         PARA_INFO_LOG("key_file: %s\n", ct->key_file);
 448         ret = ct->conf.inputs_num;
 449 out:
 450         free(home);
 451         if (ret < 0) {
 452                 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
 453                 client_close(ct);
 454                 *ct_ptr = NULL;
 455         }
 456         return ret;
 457 }
 458
 459 /**
 460  * Parse the client configuration and open a connection to para_server.
 461  *
 462  * \param argc See \ref client_parse_config.
 463  * \param argv See \ref client_parse_config.
 464  * \param ct_ptr See \ref client_parse_config.
 465  * \param loglevel See \ref client_parse_config.
 466  * \param parent See \ref client_connect().
 467  * \param child See \ref client_connect().
 468  * \param sched See \ref client_connect().
 469  *
 470  * This function combines client_parse_config() and client_connect(). It is
 471  * considered a syntax error if no command was given, i.e. if the number
 472  * of non-option arguments is zero.
 473  *
 474  * \return Standard.
 475  */
 476 int client_open(int argc, char *argv[], struct client_task **ct_ptr,
 477                 int *loglevel, struct btr_node *parent, struct btr_node *child,
 478                 struct sched *sched)
 479 {
 480         int ret = client_parse_config(argc, argv, ct_ptr, loglevel);
 481
 482         if (ret < 0)
 483                 return ret;
 484         if (ret == 0) {
 485                 ret = -E_CLIENT_SYNTAX;
 486                 goto fail;
 487         }
 488         ret = client_connect(*ct_ptr, sched, parent, child);
 489         if (ret < 0)
 490                 goto fail;
 491         return 1;
 492 fail:
 493         client_close(*ct_ptr);
 494         *ct_ptr = NULL;
 495         return ret;
 496 }