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 #include <openssl/rc4.h>
  13
  14 #include "para.h"
  15 #include "error.h"
  16 #include "list.h"
  17 #include "sched.h"
  18 #include "client.cmdline.h"
  19 #include "crypt.h"
  20 #include "rc4.h"
  21 #include "net.h"
  22 #include "fd.h"
  23 #include "string.h"
  24 #include "client.cmdline.h"
  25 #include "client.h"
  26 #include "hash.h"
  27 #include "buffer_tree.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 client_open.
  38  */
  39 void client_close(struct client_task *ct)
  40 {
  41         if (!ct)
  42                 return;
  43         if (ct->rc4c.fd >= 0)
  44                 close(ct->rc4c.fd);
  45         free(ct->user);
  46         free(ct->config_file);
  47         free(ct->key_file);
  48         client_cmdline_parser_free(&ct->conf);
  49         free(ct);
  50 }
  51
  52 /**
  53  * The preselect hook for server commands.
  54  *
  55  * \param s Pointer to the scheduler.
  56  * \param t Pointer to the task struct for this command.
  57  *
  58  * The task pointer must contain a pointer to the initialized client data
  59  * structure as it is returned by client_open().
  60  *
  61  * This function checks the state of the connection and adds the file descriptor
  62  * of the connection to the read or write fd set of \a s accordingly.
  63  *
  64  * \sa register_task() client_open(), struct sched, struct task.
  65  */
  66 static void client_pre_select(struct sched *s, struct task *t)
  67 {
  68         int ret;
  69         struct client_task *ct = container_of(t, struct client_task, task);
  70         struct btr_node *btrn = ct->btrn;
  71
  72         if (ct->rc4c.fd < 0)
  73                 return;
  74         switch (ct->status) {
  75         case CL_CONNECTED:
  76         case CL_SENT_AUTH:
  77         case CL_SENT_CH_RESPONSE:
  78         case CL_SENT_COMMAND:
  79                 para_fd_set(ct->rc4c.fd, &s->rfds, &s->max_fileno);
  80                 return;
  81
  82         case CL_RECEIVED_WELCOME:
  83         case CL_RECEIVED_PROCEED:
  84                 para_fd_set(ct->rc4c.fd, &s->wfds, &s->max_fileno);
  85                 return;
  86
  87         case CL_RECEIVING:
  88                 ret = btr_node_status(btrn, 0, BTR_NT_ROOT);
  89                 if (ret != 0) {
  90                         if (ret < 0)
  91                                 sched_min_delay(s);
  92                         else
  93                                 para_fd_set(ct->rc4c.fd, &s->rfds,
  94                                         &s->max_fileno);
  95                 }
  96                 return;
  97         case CL_SENDING:
  98                 ret = btr_node_status(btrn, 0, BTR_NT_LEAF);
  99                 if (ret != 0) {
 100                         if (ret < 0)
 101                                 sched_min_delay(s);
 102                         else
 103                                 para_fd_set(ct->rc4c.fd, &s->wfds,
 104                                         &s->max_fileno);
 105                 }
 106                 return;
 107         }
 108 }
 109
 110 static int client_recv_buffer(struct client_task *ct, fd_set *rfds,
 111                 char *buf, size_t sz, size_t *n)
 112 {
 113         int ret;
 114
 115         if (ct->status < CL_SENT_CH_RESPONSE)
 116                 return read_nonblock(ct->rc4c.fd, buf, sz, rfds, n);
 117
 118         *n = 0;
 119         ret = rc4_recv_buffer(&ct->rc4c, buf, sz);
 120         /*
 121          * rc4_recv_buffer is used with blocking fds elsewhere, so it
 122          * does not use the nonblock-API. Therefore we need to
 123          * check for EOF and EAGAIN.
 124          */
 125         if (ret == 0)
 126                 return -E_SERVER_EOF;
 127         if (ret == -ERRNO_TO_PARA_ERROR(EAGAIN))
 128                 return 0;
 129         if (ret < 0)
 130                 return ret;
 131         *n = ret;
 132         return 0;
 133 }
 134
 135 /**
 136  * The post select hook for client commands.
 137  *
 138  * \param s Pointer to the scheduler.
 139  * \param t Pointer to the task struct for this command.
 140  *
 141  * Depending on the current state of the connection and the status of the read
 142  * and write fd sets of \a s, this function performs the necessary steps to
 143  * authenticate the connection, to send the command given by \a t->private_data
 144  * and to receive para_server's output, if any.
 145  *
 146  * \sa struct sched, struct task.
 147  */
 148 static void client_post_select(struct sched *s, struct task *t)
 149 {
 150         struct client_task *ct = container_of(t, struct client_task, task);
 151         struct btr_node *btrn = ct->btrn;
 152         int ret = 0;
 153         size_t n;
 154         char buf[CLIENT_BUFSIZE];
 155
 156         t->error = 0;
 157         if (ct->rc4c.fd < 0)
 158                 return;
 159         switch (ct->status) {
 160         case CL_CONNECTED: /* receive welcome message */
 161                 ret = client_recv_buffer(ct, &s->rfds, buf, sizeof(buf), &n);
 162                 if (ret < 0 || n == 0)
 163                         goto out;
 164                 ct->status = CL_RECEIVED_WELCOME;
 165                 return;
 166         case CL_RECEIVED_WELCOME: /* send auth command */
 167                 sprintf(buf, AUTH_REQUEST_MSG "%s", ct->user);
 168                 PARA_INFO_LOG("--> %s\n", buf);
 169                 if (!FD_ISSET(ct->rc4c.fd, &s->wfds))
 170                         return;
 171                 ret = send_buffer(ct->rc4c.fd, buf);
 172                 if (ret < 0)
 173                         goto out;
 174                 ct->status = CL_SENT_AUTH;
 175                 return;
 176         case CL_SENT_AUTH:
 177                 /*
 178                  * Receive challenge and rc4 keys, decrypt the challenge and
 179                  * send back the hash of the decrypted challenge.
 180                  */
 181                 {
 182                 /* decrypted challenge/rc4 buffer */
 183                 unsigned char crypt_buf[1024];
 184                 /* the SHA1 of the decrypted challenge */
 185                 unsigned char challenge_sha1[HASH_SIZE];
 186
 187                 ret = client_recv_buffer(ct, &s->rfds, buf, sizeof(buf), &n);
 188                 if (ret < 0 || n == 0)
 189                         goto out;
 190                 PARA_INFO_LOG("<-- [challenge] (%zu bytes)\n", n);
 191                 ret = para_decrypt_buffer(ct->key_file, crypt_buf,
 192                         (unsigned char *)buf, n);
 193                 if (ret < 0)
 194                         goto out;
 195                 sha1_hash((char *)crypt_buf, CHALLENGE_SIZE, challenge_sha1);
 196                 RC4_set_key(&ct->rc4c.send_key, RC4_KEY_LEN,
 197                         crypt_buf + CHALLENGE_SIZE);
 198                 RC4_set_key(&ct->rc4c.recv_key, RC4_KEY_LEN,
 199                         crypt_buf + CHALLENGE_SIZE + RC4_KEY_LEN);
 200                 hash_to_asc(challenge_sha1, buf);
 201                 PARA_INFO_LOG("--> %s\n", buf);
 202                 ret = send_bin_buffer(ct->rc4c.fd, (char *)challenge_sha1,
 203                         HASH_SIZE);
 204                 if (ret < 0)
 205                         goto out;
 206                 ct->status = CL_SENT_CH_RESPONSE;
 207                 return;
 208                 }
 209         case CL_SENT_CH_RESPONSE: /* read server response */
 210                 {
 211                 ret = client_recv_buffer(ct, &s->rfds, buf, sizeof(buf), &n);
 212                 if (ret < 0 || n == 0)
 213                         goto out;
 214                 /* check if server has sent "Proceed" message */
 215                 ret = -E_CLIENT_AUTH;
 216                 if (n < PROCEED_MSG_LEN)
 217                         goto out;
 218                 if (!strstr(buf, PROCEED_MSG))
 219                         goto out;
 220                 ct->status = CL_RECEIVED_PROCEED;
 221                 return;
 222                 }
 223         case CL_RECEIVED_PROCEED: /* concat args and send command */
 224                 {
 225                 int i;
 226                 char *command = NULL;
 227                 if (!FD_ISSET(ct->rc4c.fd, &s->wfds))
 228                         return;
 229                 for (i = 0; i < ct->conf.inputs_num; i++) {
 230                         char *tmp = command;
 231                         command = make_message("%s\n%s", command?
 232                                 command : "", ct->conf.inputs[i]);
 233                         free(tmp);
 234                 }
 235                 command = para_strcat(command, EOC_MSG "\n");
 236                 PARA_DEBUG_LOG("--> %s\n", command);
 237                 ret = rc4_send_buffer(&ct->rc4c, command);
 238                 free(command);
 239                 if (ret < 0)
 240                         goto out;
 241                 ct->status = CL_SENT_COMMAND;
 242                 return;
 243                 }
 244         case CL_SENT_COMMAND:
 245                 {
 246                 char *buf2;
 247                 /* can not use "buf" here because we need a malloced buffer */
 248                 buf2 = para_malloc(CLIENT_BUFSIZE);
 249                 ret = client_recv_buffer(ct, &s->rfds, buf2, CLIENT_BUFSIZE, &n);
 250                 if (n > 0) {
 251                         if (strstr(buf2, AWAITING_DATA_MSG)) {
 252                                 free(buf2);
 253                                 ct->status = CL_SENDING;
 254                                 return;
 255                         }
 256                         ct->status = CL_RECEIVING;
 257                         btr_add_output(buf2, n, btrn);
 258                 } else
 259                         free(buf2);
 260                 goto out;
 261                 }
 262         case CL_SENDING:
 263                 {
 264                 char *buf2;
 265                 size_t sz;
 266                 ret = btr_node_status(btrn, 0, BTR_NT_LEAF);
 267                 if (ret < 0)
 268                         goto out;
 269                 if (ret == 0)
 270                         return;
 271                 if (!FD_ISSET(ct->rc4c.fd, &s->wfds))
 272                         return;
 273                 sz = btr_next_buffer(btrn, &buf2);
 274                 ret = rc4_send_bin_buffer(&ct->rc4c, buf2, sz);
 275                 if (ret < 0)
 276                         goto out;
 277                 btr_consume(btrn, sz);
 278                 return;
 279                 }
 280         case CL_RECEIVING:
 281                 {
 282                 char *buf2;
 283                 ret = btr_node_status(btrn, 0, BTR_NT_ROOT);
 284                 if (ret < 0)
 285                         goto out;
 286                 if (ret == 0)
 287                         return;
 288                 /*
 289                  * The FD_ISSET() is not strictly necessary, but is allows us
 290                  * to skip the malloc below if there is nothing to read anyway.
 291                  */
 292                 if (!FD_ISSET(ct->rc4c.fd, &s->rfds))
 293                         return;
 294                 buf2 = para_malloc(CLIENT_BUFSIZE);
 295                 ret = client_recv_buffer(ct, &s->rfds, buf2, CLIENT_BUFSIZE, &n);
 296                 if (n > 0) {
 297                         buf2 = para_realloc(buf2, n);
 298                         btr_add_output(buf2, n, btrn);
 299                 } else
 300                         free(buf2);
 301                 goto out;
 302                 }
 303         }
 304 out:
 305         t->error = ret;
 306         if (ret < 0) {
 307                 if (ret != -E_SERVER_EOF && ret != -E_BTR_EOF)
 308                         PARA_ERROR_LOG("%s\n", para_strerror(-t->error));
 309                 btr_remove_node(btrn);
 310         }
 311 }
 312
 313 /* connect to para_server and register the client task */
 314 static int client_connect(struct client_task *ct)
 315 {
 316         int ret;
 317
 318         ct->rc4c.fd = -1;
 319         ret = para_connect_simple(IPPROTO_TCP, ct->conf.hostname_arg,
 320                                                ct->conf.server_port_arg);
 321         if (ret < 0)
 322                 return ret;
 323         ct->rc4c.fd = ret;
 324         ct->status = CL_CONNECTED;
 325         ret = mark_fd_nonblocking(ct->rc4c.fd);
 326         if (ret < 0)
 327                 goto err_out;
 328         ct->task.pre_select = client_pre_select;
 329         ct->task.post_select = client_post_select;
 330         sprintf(ct->task.status, "client");
 331         register_task(&ct->task);
 332         return 1;
 333 err_out:
 334         close(ct->rc4c.fd);
 335         ct->rc4c.fd = -1;
 336         return ret;
 337 }
 338
 339 /**
 340  * Open connection to para_server.
 341  *
 342  * \param argc Usual argument count.
 343  * \param argv Usual argument vector.
 344  * \param ct_ptr Points to dynamically allocated and initialized client task
 345  * struct upon successful return.
 346  * \param loglevel If not \p NULL, the number of the loglevel is stored here.
 347  * \param parent Add the new buffer tree node as a child of this node.
 348  * \param child Add the new buffer tree node as a parent of this node.
 349  *
 350  * Check the command line options given by \a argc and argv, set default values
 351  * for user name and rsa key file, read further option from the config file.
 352  * Finally, establish a connection to para_server.
 353  *
 354  * \return Standard.
 355  */
 356 int client_open(int argc, char *argv[], struct client_task **ct_ptr,
 357                 int *loglevel, struct btr_node *parent, struct btr_node *child)
 358 {
 359         char *home = para_homedir();
 360         int ret;
 361         struct client_task *ct = para_calloc(sizeof(struct client_task));
 362
 363         ct->btrn = btr_new_node(&(struct btr_node_description)
 364                 EMBRACE(.name = "client", .parent = parent, .child = child));
 365         *ct_ptr = ct;
 366         ct->rc4c.fd = -1;
 367         ret = -E_CLIENT_SYNTAX;
 368         if (client_cmdline_parser(argc, argv, &ct->conf))
 369                 goto out;
 370         HANDLE_VERSION_FLAG("client", ct->conf);
 371         ret = -E_CLIENT_SYNTAX;
 372         if (!ct->conf.inputs_num)
 373                 goto out;
 374
 375         ct->config_file = ct->conf.config_file_given?
 376                 para_strdup(ct->conf.config_file_arg) :
 377                 make_message("%s/.paraslash/client.conf", home);
 378         ret = file_exists(ct->config_file);
 379         if (!ret && ct->conf.config_file_given) {
 380                 ret = -E_NO_CONFIG;
 381                 goto out;
 382         }
 383         if (ret) {
 384                 struct client_cmdline_parser_params params = {
 385                         .override = 0,
 386                         .initialize = 0,
 387                         .check_required = 0,
 388                         .check_ambiguity = 0,
 389                         .print_errors = 0
 390                 };
 391                 ret = -E_BAD_CONFIG;
 392                 if (client_cmdline_parser_config_file(ct->config_file,
 393                         &ct->conf, &params))
 394                         goto out;
 395         }
 396         ct->user = ct->conf.user_given?
 397                 para_strdup(ct->conf.user_arg) : para_logname();
 398
 399         ct->key_file = ct->conf.key_file_given?
 400                 para_strdup(ct->conf.key_file_arg) :
 401                 make_message("%s/.paraslash/key.%s", home, ct->user);
 402
 403         if (loglevel)
 404                 *loglevel = get_loglevel_by_name(ct->conf.loglevel_arg);
 405         PARA_INFO_LOG("loglevel: %s\n", ct->conf.loglevel_arg);
 406         PARA_INFO_LOG("config_file: %s\n", ct->config_file);
 407         PARA_INFO_LOG("key_file: %s\n", ct->key_file);
 408         PARA_NOTICE_LOG("connecting %s:%d\n", ct->conf.hostname_arg,
 409                 ct->conf.server_port_arg);
 410         ret = client_connect(ct);
 411 out:
 412         free(home);
 413         if (ret < 0) {
 414                 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
 415                 btr_remove_node(ct->btrn);
 416                 btr_free_node(ct->btrn);
 417                 client_close(ct);
 418                 *ct_ptr = NULL;
 419         }
 420         return ret;
 421 }