client_common.c

   1 /*
   2  * Copyright (C) 1997-2011 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 #include <dirent.h>
  12
  13 #include "para.h"
  14 #include "error.h"
  15 #include "list.h"
  16 #include "sched.h"
  17 #include "client.cmdline.h"
  18 #include "crypt.h"
  19 #include "rc4.h"
  20 #include "net.h"
  21 #include "fd.h"
  22 #include "string.h"
  23 #include "client.cmdline.h"
  24 #include "client.h"
  25 #include "hash.h"
  26 #include "buffer_tree.h"
  27
  28 /** The size of the receiving buffer. */
  29 #define CLIENT_BUFSIZE 4000
  30
  31 /**
  32  * Close the connection to para_server and free all resources.
  33  *
  34  * \param ct Pointer to the client data.
  35  *
  36  * \sa client_open.
  37  */
  38 void client_close(struct client_task *ct)
  39 {
  40         if (!ct)
  41                 return;
  42         if (ct->rc4c.fd >= 0)
  43                 close(ct->rc4c.fd);
  44         stream_cipher_free(ct->rc4c.recv);
  45         stream_cipher_free(ct->rc4c.send);
  46         free(ct->user);
  47         free(ct->config_file);
  48         free(ct->key_file);
  49         client_cmdline_parser_free(&ct->conf);
  50         free(ct);
  51 }
  52
  53 /**
  54  * The preselect hook for server commands.
  55  *
  56  * \param s Pointer to the scheduler.
  57  * \param t Pointer to the task struct for this command.
  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 \a s accordingly.
  64  *
  65  * \sa register_task() client_open(), struct sched, struct task.
  66  */
  67 static void client_pre_select(struct sched *s, struct task *t)
  68 {
  69         int ret;
  70         struct client_task *ct = container_of(t, struct client_task, task);
  71         struct btr_node *btrn = ct->btrn;
  72
  73         if (ct->rc4c.fd < 0)
  74                 return;
  75         switch (ct->status) {
  76         case CL_CONNECTED:
  77         case CL_SENT_AUTH:
  78         case CL_SENT_CH_RESPONSE:
  79         case CL_SENT_COMMAND:
  80                 para_fd_set(ct->rc4c.fd, &s->rfds, &s->max_fileno);
  81                 return;
  82
  83         case CL_RECEIVED_WELCOME:
  84         case CL_RECEIVED_PROCEED:
  85                 para_fd_set(ct->rc4c.fd, &s->wfds, &s->max_fileno);
  86                 return;
  87
  88         case CL_RECEIVING:
  89                 ret = btr_node_status(btrn, 0, BTR_NT_ROOT);
  90                 if (ret != 0) {
  91                         if (ret < 0)
  92                                 sched_min_delay(s);
  93                         else
  94                                 para_fd_set(ct->rc4c.fd, &s->rfds,
  95                                         &s->max_fileno);
  96                 }
  97                 return;
  98         case CL_SENDING:
  99                 ret = btr_node_status(btrn, 0, BTR_NT_LEAF);
 100                 if (ret != 0) {
 101                         if (ret < 0)
 102                                 sched_min_delay(s);
 103                         else
 104                                 para_fd_set(ct->rc4c.fd, &s->wfds,
 105                                         &s->max_fileno);
 106                 }
 107                 return;
 108         }
 109 }
 110
 111 static int client_recv_buffer(struct client_task *ct, fd_set *rfds,
 112                 char *buf, size_t sz, size_t *n)
 113 {
 114         int ret;
 115
 116         if (ct->status < CL_SENT_CH_RESPONSE)
 117                 return read_nonblock(ct->rc4c.fd, buf, sz, rfds, n);
 118
 119         *n = 0;
 120         ret = rc4_recv_buffer(&ct->rc4c, buf, sz);
 121         /*
 122          * rc4_recv_buffer is used with blocking fds elsewhere, so it
 123          * does not use the nonblock-API. Therefore we need to
 124          * check for EOF and EAGAIN.
 125          */
 126         if (ret == 0)
 127                 return -E_SERVER_EOF;
 128         if (ret == -ERRNO_TO_PARA_ERROR(EAGAIN))
 129                 return 0;
 130         if (ret < 0)
 131                 return ret;
 132         *n = ret;
 133         return 0;
 134 }
 135
 136 /**
 137  * The post select hook for client commands.
 138  *
 139  * \param s Pointer to the scheduler.
 140  * \param t Pointer to the task struct for this command.
 141  *
 142  * Depending on the current state of the connection and the status of the read
 143  * and write fd sets of \a s, this function performs the necessary steps to
 144  * authenticate the connection, to send the command given by \a t->private_data
 145  * and to receive para_server's output, if any.
 146  *
 147  * \sa struct sched, struct task.
 148  */
 149 static void client_post_select(struct sched *s, struct task *t)
 150 {
 151         struct client_task *ct = container_of(t, struct client_task, task);
 152         struct btr_node *btrn = ct->btrn;
 153         int ret = 0;
 154         size_t n;
 155         char buf[CLIENT_BUFSIZE];
 156
 157         t->error = 0;
 158         if (ct->rc4c.fd < 0)
 159                 return;
 160         switch (ct->status) {
 161         case CL_CONNECTED: /* receive welcome message */
 162                 ret = client_recv_buffer(ct, &s->rfds, buf, sizeof(buf), &n);
 163                 if (ret < 0 || n == 0)
 164                         goto out;
 165                 ct->status = CL_RECEIVED_WELCOME;
 166                 return;
 167         case CL_RECEIVED_WELCOME: /* send auth command */
 168                 sprintf(buf, AUTH_REQUEST_MSG "%s", ct->user);
 169                 PARA_INFO_LOG("--> %s\n", buf);
 170                 if (!FD_ISSET(ct->rc4c.fd, &s->wfds))
 171                         return;
 172                 ret = send_buffer(ct->rc4c.fd, buf);
 173                 if (ret < 0)
 174                         goto out;
 175                 ct->status = CL_SENT_AUTH;
 176                 return;
 177         case CL_SENT_AUTH:
 178                 /*
 179                  * Receive challenge and rc4 keys, decrypt the challenge and
 180                  * send back the hash of the decrypted challenge.
 181                  */
 182                 {
 183                 /* decrypted challenge/rc4 buffer */
 184                 unsigned char crypt_buf[1024];
 185                 /* the SHA1 of the decrypted challenge */
 186                 unsigned char challenge_sha1[HASH_SIZE];
 187
 188                 ret = client_recv_buffer(ct, &s->rfds, buf, sizeof(buf), &n);
 189                 if (ret < 0 || n == 0)
 190                         goto out;
 191                 PARA_INFO_LOG("<-- [challenge] (%zu bytes)\n", n);
 192                 ret = priv_decrypt(ct->key_file, crypt_buf,
 193                         (unsigned char *)buf, n);
 194                 if (ret < 0)
 195                         goto out;
 196                 sha1_hash((char *)crypt_buf, CHALLENGE_SIZE, challenge_sha1);
 197                 ct->rc4c.send = stream_cipher_new(crypt_buf + CHALLENGE_SIZE,
 198                         RC4_KEY_LEN);
 199                 ct->rc4c.recv = stream_cipher_new(crypt_buf + CHALLENGE_SIZE
 200                         + RC4_KEY_LEN, RC4_KEY_LEN);
 201                 hash_to_asc(challenge_sha1, buf);
 202                 PARA_INFO_LOG("--> %s\n", buf);
 203                 ret = send_bin_buffer(ct->rc4c.fd, (char *)challenge_sha1,
 204                         HASH_SIZE);
 205                 if (ret < 0)
 206                         goto out;
 207                 ct->status = CL_SENT_CH_RESPONSE;
 208                 return;
 209                 }
 210         case CL_SENT_CH_RESPONSE: /* read server response */
 211                 {
 212                 ret = client_recv_buffer(ct, &s->rfds, buf, sizeof(buf), &n);
 213                 if (ret < 0 || n == 0)
 214                         goto out;
 215                 /* check if server has sent "Proceed" message */
 216                 ret = -E_CLIENT_AUTH;
 217                 if (n < PROCEED_MSG_LEN)
 218                         goto out;
 219                 if (!strstr(buf, PROCEED_MSG))
 220                         goto out;
 221                 ct->status = CL_RECEIVED_PROCEED;
 222                 return;
 223                 }
 224         case CL_RECEIVED_PROCEED: /* concat args and send command */
 225                 {
 226                 int i;
 227                 char *command = NULL;
 228                 if (!FD_ISSET(ct->rc4c.fd, &s->wfds))
 229                         return;
 230                 for (i = 0; i < ct->conf.inputs_num; i++) {
 231                         char *tmp = command;
 232                         command = make_message("%s\n%s", command?
 233                                 command : "", ct->conf.inputs[i]);
 234                         free(tmp);
 235                 }
 236                 command = para_strcat(command, EOC_MSG "\n");
 237                 PARA_DEBUG_LOG("--> %s\n", command);
 238                 ret = rc4_send_buffer(&ct->rc4c, command);
 239                 free(command);
 240                 if (ret < 0)
 241                         goto out;
 242                 ct->status = CL_SENT_COMMAND;
 243                 return;
 244                 }
 245         case CL_SENT_COMMAND:
 246                 {
 247                 char *buf2;
 248                 /* can not use "buf" here because we need a malloced buffer */
 249                 buf2 = para_malloc(CLIENT_BUFSIZE);
 250                 ret = client_recv_buffer(ct, &s->rfds, buf2, CLIENT_BUFSIZE, &n);
 251                 if (n > 0) {
 252                         if (strstr(buf2, AWAITING_DATA_MSG)) {
 253                                 free(buf2);
 254                                 ct->status = CL_SENDING;
 255                                 return;
 256                         }
 257                         ct->status = CL_RECEIVING;
 258                         btr_add_output(buf2, n, btrn);
 259                 } else
 260                         free(buf2);
 261                 goto out;
 262                 }
 263         case CL_SENDING:
 264                 {
 265                 char *buf2;
 266                 size_t sz;
 267                 ret = btr_node_status(btrn, 0, BTR_NT_LEAF);
 268                 if (ret < 0)
 269                         goto out;
 270                 if (ret == 0)
 271                         return;
 272                 if (!FD_ISSET(ct->rc4c.fd, &s->wfds))
 273                         return;
 274                 sz = btr_next_buffer(btrn, &buf2);
 275                 ret = rc4_send_bin_buffer(&ct->rc4c, buf2, sz);
 276                 if (ret < 0)
 277                         goto out;
 278                 btr_consume(btrn, sz);
 279                 return;
 280                 }
 281         case CL_RECEIVING:
 282                 {
 283                 char *buf2;
 284                 ret = btr_node_status(btrn, 0, BTR_NT_ROOT);
 285                 if (ret < 0)
 286                         goto out;
 287                 if (ret == 0)
 288                         return;
 289                 /*
 290                  * The FD_ISSET() is not strictly necessary, but is allows us
 291                  * to skip the malloc below if there is nothing to read anyway.
 292                  */
 293                 if (!FD_ISSET(ct->rc4c.fd, &s->rfds))
 294                         return;
 295                 buf2 = para_malloc(CLIENT_BUFSIZE);
 296                 ret = client_recv_buffer(ct, &s->rfds, buf2, CLIENT_BUFSIZE, &n);
 297                 if (n > 0) {
 298                         buf2 = para_realloc(buf2, n);
 299                         btr_add_output(buf2, n, btrn);
 300                 } else
 301                         free(buf2);
 302                 goto out;
 303                 }
 304         }
 305 out:
 306         t->error = ret;
 307         if (ret < 0) {
 308                 if (ret != -E_SERVER_EOF && ret != -E_BTR_EOF)
 309                         PARA_ERROR_LOG("%s\n", para_strerror(-t->error));
 310                 btr_remove_node(btrn);
 311         }
 312 }
 313
 314 /* connect to para_server and register the client task */
 315 static int client_connect(struct client_task *ct)
 316 {
 317         int ret;
 318
 319         ct->rc4c.fd = -1;
 320         ret = para_connect_simple(IPPROTO_TCP, ct->conf.hostname_arg,
 321                                                ct->conf.server_port_arg);
 322         if (ret < 0)
 323                 return ret;
 324         ct->rc4c.fd = ret;
 325         ct->status = CL_CONNECTED;
 326         ret = mark_fd_nonblocking(ct->rc4c.fd);
 327         if (ret < 0)
 328                 goto err_out;
 329         ct->task.pre_select = client_pre_select;
 330         ct->task.post_select = client_post_select;
 331         sprintf(ct->task.status, "client");
 332         register_task(&ct->task);
 333         return 1;
 334 err_out:
 335         close(ct->rc4c.fd);
 336         ct->rc4c.fd = -1;
 337         return ret;
 338 }
 339
 340 /**
 341  * Open connection to para_server.
 342  *
 343  * \param argc Usual argument count.
 344  * \param argv Usual argument vector.
 345  * \param ct_ptr Points to dynamically allocated and initialized client task
 346  * struct upon successful return.
 347  * \param loglevel If not \p NULL, the number of the loglevel is stored here.
 348  * \param parent Add the new buffer tree node as a child of this node.
 349  * \param child Add the new buffer tree node as a parent of this node.
 350  *
 351  * Check the command line options given by \a argc and argv, set default values
 352  * for user name and rsa key file, read further option from the config file.
 353  * Finally, establish a connection to para_server.
 354  *
 355  * \return Standard.
 356  */
 357 int client_open(int argc, char *argv[], struct client_task **ct_ptr,
 358                 int *loglevel, struct btr_node *parent, struct btr_node *child)
 359 {
 360         char *home = para_homedir();
 361         int ret;
 362         struct client_task *ct = para_calloc(sizeof(struct client_task));
 363
 364         ct->btrn = btr_new_node(&(struct btr_node_description)
 365                 EMBRACE(.name = "client", .parent = parent, .child = child));
 366         *ct_ptr = ct;
 367         ct->rc4c.fd = -1;
 368         ret = -E_CLIENT_SYNTAX;
 369         if (client_cmdline_parser(argc, argv, &ct->conf))
 370                 goto out;
 371         HANDLE_VERSION_FLAG("client", ct->conf);
 372         ret = -E_CLIENT_SYNTAX;
 373         if (!ct->conf.inputs_num)
 374                 goto out;
 375
 376         ct->config_file = ct->conf.config_file_given?
 377                 para_strdup(ct->conf.config_file_arg) :
 378                 make_message("%s/.paraslash/client.conf", home);
 379         ret = file_exists(ct->config_file);
 380         if (!ret && ct->conf.config_file_given) {
 381                 ret = -E_NO_CONFIG;
 382                 goto out;
 383         }
 384         if (ret) {
 385                 struct client_cmdline_parser_params params = {
 386                         .override = 0,
 387                         .initialize = 0,
 388                         .check_required = 0,
 389                         .check_ambiguity = 0,
 390                         .print_errors = 0
 391                 };
 392                 ret = -E_BAD_CONFIG;
 393                 if (client_cmdline_parser_config_file(ct->config_file,
 394                         &ct->conf, &params))
 395                         goto out;
 396         }
 397         ct->user = ct->conf.user_given?
 398                 para_strdup(ct->conf.user_arg) : para_logname();
 399
 400         ct->key_file = ct->conf.key_file_given?
 401                 para_strdup(ct->conf.key_file_arg) :
 402                 make_message("%s/.paraslash/key.%s", home, ct->user);
 403
 404         if (loglevel)
 405                 *loglevel = get_loglevel_by_name(ct->conf.loglevel_arg);
 406         PARA_INFO_LOG("loglevel: %s\n", ct->conf.loglevel_arg);
 407         PARA_INFO_LOG("config_file: %s\n", ct->config_file);
 408         PARA_INFO_LOG("key_file: %s\n", ct->key_file);
 409         PARA_NOTICE_LOG("connecting %s:%d\n", ct->conf.hostname_arg,
 410                 ct->conf.server_port_arg);
 411         ret = client_connect(ct);
 412 out:
 413         free(home);
 414         if (ret < 0) {
 415                 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
 416                 btr_remove_node(ct->btrn);
 417                 btr_free_node(ct->btrn);
 418                 client_close(ct);
 419                 *ct_ptr = NULL;
 420         }
 421         return ret;
 422 }