lib/libc/net/nscachedcli.c

   1 /*-
   2  * Copyright (c) 2005 Michael Bushkov <bushman@rsu.ru>
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  *
  26  * $FreeBSD: src/lib/libc/net/nscachedcli.c,v 1.3 2006/12/04 17:08:43 ume Exp $
  27  */
  28
  29 #include "namespace.h"
  30 #include <sys/types.h>
  31 #include <sys/socket.h>
  32 #include <sys/event.h>
  33 #include <sys/uio.h>
  34 #include <sys/un.h>
  35 #include <assert.h>
  36 #include <errno.h>
  37 #include <fcntl.h>
  38 #include <stdlib.h>
  39 #include <string.h>
  40 #include <unistd.h>
  41 #include "un-namespace.h"
  42 #include "nscachedcli.h"
  43
  44 #define NS_DEFAULT_CACHED_IO_TIMEOUT    4
  45
  46 static int safe_write(struct cached_connection_ *, const void *, size_t);
  47 static int safe_read(struct cached_connection_ *, void *, size_t);
  48 static int send_credentials(struct cached_connection_ *, int);
  49
  50 /*
  51  * safe_write writes data to the specified connection and tries to do it in
  52  * the very safe manner. We ensure, that we can write to the socket with
  53  * kevent. If the data_size can't be sent in one piece, then it would be
  54  * splitted.
  55  */
  56 static int
  57 safe_write(struct cached_connection_ *connection, const void *data,
  58     size_t data_size)
  59 {
  60         struct kevent eventlist;
  61         int nevents;
  62         size_t result;
  63         ssize_t s_result;
  64         struct timespec timeout;
  65
  66         if (data_size == 0)
  67                 return (0);
  68
  69         timeout.tv_sec = NS_DEFAULT_CACHED_IO_TIMEOUT;
  70         timeout.tv_nsec = 0;
  71         result = 0;
  72         do {
  73                 nevents = _kevent(connection->write_queue, NULL, 0, &eventlist,
  74                     1, &timeout);
  75                 if ((nevents == 1) && (eventlist.filter == EVFILT_WRITE)) {
  76                         s_result = _write(connection->sockfd,
  77                             (char *)data + result,
  78                             eventlist.data < data_size - result ?
  79                             eventlist.data : data_size - result);
  80                         if (s_result == -1)
  81                                 return (-1);
  82                         else
  83                                 result += s_result;
  84
  85                         if (eventlist.flags & EV_EOF)
  86                                 return (result < data_size ? -1 : 0);
  87                 } else
  88                         return (-1);
  89         } while (result < data_size);
  90
  91         return (0);
  92 }
  93
  94 /*
  95  * safe_read reads data from connection and tries to do it in the very safe
  96  * and stable way. It uses kevent to ensure, that the data are availabe for
  97  * reading. If the amount of data to be read is too large, then they would
  98  * be splitted.
  99  */
 100 static int
 101 safe_read(struct cached_connection_ *connection, void *data, size_t data_size)
 102 {
 103         struct kevent eventlist;
 104         size_t result;
 105         ssize_t s_result;
 106         struct timespec timeout;
 107         int nevents;
 108
 109         if (data_size == 0)
 110                 return (0);
 111
 112         timeout.tv_sec = NS_DEFAULT_CACHED_IO_TIMEOUT;
 113         timeout.tv_nsec = 0;
 114         result = 0;
 115         do {
 116                 nevents = _kevent(connection->read_queue, NULL, 0, &eventlist,
 117                     1, &timeout);
 118                 if (nevents == 1 && eventlist.filter == EVFILT_READ) {
 119                         s_result = _read(connection->sockfd,
 120                             (char *)data + result,
 121                             eventlist.data <= data_size - result ?
 122                             eventlist.data : data_size - result);
 123                         if (s_result == -1)
 124                                 return (-1);
 125                         else
 126                                 result += s_result;
 127
 128                         if (eventlist.flags & EV_EOF)
 129                                 return (result < data_size ? -1 : 0);
 130                 } else
 131                         return (-1);
 132         } while (result < data_size);
 133
 134         return (0);
 135 }
 136
 137 /*
 138  * Sends the credentials information to the connection along with the
 139  * communication element type.
 140  */
 141 static int
 142 send_credentials(struct cached_connection_ *connection, int type)
 143 {
 144         struct kevent eventlist;
 145         int nevents;
 146         ssize_t result;
 147         int res __unused;
 148
 149         struct msghdr cred_hdr;
 150         struct iovec iov;
 151
 152         struct {
 153                 struct cmsghdr hdr;
 154                 char cred[CMSG_SPACE(sizeof(struct cmsgcred))];
 155         } cmsg;
 156
 157         memset(&cmsg, 0, sizeof(cmsg));
 158         cmsg.hdr.cmsg_len =  CMSG_LEN(sizeof(struct cmsgcred));
 159         cmsg.hdr.cmsg_level = SOL_SOCKET;
 160         cmsg.hdr.cmsg_type = SCM_CREDS;
 161
 162         memset(&cred_hdr, 0, sizeof(struct msghdr));
 163         cred_hdr.msg_iov = &iov;
 164         cred_hdr.msg_iovlen = 1;
 165         cred_hdr.msg_control = (caddr_t)&cmsg;
 166         cred_hdr.msg_controllen = CMSG_SPACE(sizeof(struct cmsgcred));
 167
 168         iov.iov_base = &type;
 169         iov.iov_len = sizeof(int);
 170
 171         EV_SET(&eventlist, connection->sockfd, EVFILT_WRITE, EV_ADD,
 172             NOTE_LOWAT, sizeof(int), NULL);
 173         res = _kevent(connection->write_queue, &eventlist, 1, NULL, 0, NULL);
 174
 175         nevents = _kevent(connection->write_queue, NULL, 0, &eventlist, 1,
 176             NULL);
 177         if (nevents == 1 && eventlist.filter == EVFILT_WRITE) {
 178                 result = (_sendmsg(connection->sockfd, &cred_hdr, 0) == -1) ?
 179                     -1 : 0;
 180                 EV_SET(&eventlist, connection->sockfd, EVFILT_WRITE, EV_ADD,
 181                     0, 0, NULL);
 182                 _kevent(connection->write_queue, &eventlist, 1, NULL, 0, NULL);
 183                 return (result);
 184         } else
 185                 return (-1);
 186 }
 187
 188 /*
 189  * Opens the connection with the specified params. Initializes all kqueues.
 190  */
 191 struct cached_connection_ *
 192 __open_cached_connection(struct cached_connection_params const *params)
 193 {
 194         struct cached_connection_ *retval;
 195         struct kevent eventlist;
 196         struct sockaddr_un client_address;
 197         int client_address_len, client_socket;
 198         int res;
 199
 200         assert(params != NULL);
 201
 202         client_socket = _socket(PF_LOCAL, SOCK_STREAM, 0);
 203         client_address.sun_family = PF_LOCAL;
 204         strncpy(client_address.sun_path, params->socket_path,
 205             sizeof(client_address.sun_path));
 206         client_address_len = sizeof(client_address.sun_family) +
 207             strlen(client_address.sun_path) + 1;
 208
 209         res = _connect(client_socket, (struct sockaddr *)&client_address,
 210             client_address_len);
 211         if (res == -1) {
 212                 _close(client_socket);
 213                 return (NULL);
 214         }
 215         _fcntl(client_socket, F_SETFL, O_NONBLOCK);
 216
 217         retval = malloc(sizeof(struct cached_connection_));
 218         assert(retval != NULL);
 219         memset(retval, 0, sizeof(struct cached_connection_));
 220
 221         retval->sockfd = client_socket;
 222
 223         retval->write_queue = kqueue();
 224         assert(retval->write_queue != -1);
 225
 226         EV_SET(&eventlist, retval->sockfd, EVFILT_WRITE, EV_ADD, 0, 0, NULL);
 227         res = _kevent(retval->write_queue, &eventlist, 1, NULL, 0, NULL);
 228
 229         retval->read_queue = kqueue();
 230         assert(retval->read_queue != -1);
 231
 232         EV_SET(&eventlist, retval->sockfd, EVFILT_READ, EV_ADD, 0, 0, NULL);
 233         res = _kevent(retval->read_queue, &eventlist, 1, NULL, 0, NULL);
 234
 235         return (retval);
 236 }
 237
 238 void
 239 __close_cached_connection(struct cached_connection_ *connection)
 240 {
 241         assert(connection != NULL);
 242
 243         _close(connection->sockfd);
 244         _close(connection->read_queue);
 245         _close(connection->write_queue);
 246         free(connection);
 247 }
 248
 249 /*
 250  * This function is very close to the cache_write function of the caching
 251  * library, which is used in the caching daemon. It caches the data with the
 252  * specified key in the cache entry with entry_name.
 253  */
 254 int
 255 __cached_write(struct cached_connection_ *connection, const char *entry_name,
 256     const char *key, size_t key_size, const char *data, size_t data_size)
 257 {
 258         size_t name_size;
 259         int error_code;
 260         int result;
 261
 262         error_code = -1;
 263         result = send_credentials(connection, CET_WRITE_REQUEST);
 264         if (result != 0)
 265                 goto fin;
 266
 267         name_size = strlen(entry_name);
 268         result = safe_write(connection, &name_size, sizeof(size_t));
 269         if (result != 0)
 270                 goto fin;
 271
 272         result = safe_write(connection, &key_size, sizeof(size_t));
 273         if (result != 0)
 274                 goto fin;
 275
 276         result = safe_write(connection, &data_size, sizeof(size_t));
 277         if (result != 0)
 278                 goto fin;
 279
 280         result = safe_write(connection, entry_name, name_size);
 281         if (result != 0)
 282                 goto fin;
 283
 284         result = safe_write(connection, key, key_size);
 285         if (result != 0)
 286                 goto fin;
 287
 288         result = safe_write(connection, data, data_size);
 289         if (result != 0)
 290                 goto fin;
 291
 292         result = safe_read(connection, &error_code, sizeof(int));
 293         if (result != 0)
 294                 error_code = -1;
 295
 296 fin:
 297         return (error_code);
 298 }
 299
 300 /*
 301  * This function is very close to the cache_read function of the caching
 302  * library, which is used in the caching daemon. It reads cached data with the
 303  * specified key from the cache entry with entry_name.
 304  */
 305 int
 306 __cached_read(struct cached_connection_ *connection, const char *entry_name,
 307     const char *key, size_t key_size, char *data, size_t *data_size)
 308 {
 309         size_t name_size, result_size;
 310         int error_code, rec_error_code;
 311         int result;
 312
 313         assert(connection != NULL);
 314         result = 0;
 315         error_code = -1;
 316
 317         result = send_credentials(connection, CET_READ_REQUEST);
 318         if (result != 0)
 319                 goto fin;
 320
 321         name_size = strlen(entry_name);
 322         result = safe_write(connection, &name_size, sizeof(size_t));
 323         if (result != 0)
 324                 goto fin;
 325
 326         result = safe_write(connection, &key_size, sizeof(size_t));
 327         if (result != 0)
 328                 goto fin;
 329
 330         result = safe_write(connection, entry_name, name_size);
 331         if (result != 0)
 332                 goto fin;
 333
 334         result = safe_write(connection, key, key_size);
 335         if (result != 0)
 336                 goto fin;
 337
 338         result = safe_read(connection, &rec_error_code, sizeof(int));
 339         if (result != 0)
 340                 goto fin;
 341
 342         if (rec_error_code != 0) {
 343                 error_code = rec_error_code;
 344                 goto fin;
 345         }
 346
 347         result = safe_read(connection, &result_size, sizeof(size_t));
 348         if (result != 0)
 349                 goto fin;
 350
 351         if (result_size > *data_size) {
 352                 *data_size = result_size;
 353                 error_code = -2;
 354                 goto fin;
 355         }
 356
 357         result = safe_read(connection, data, result_size);
 358         if (result != 0)
 359                 goto fin;
 360
 361         *data_size = result_size;
 362         error_code = 0;
 363
 364 fin:
 365         return (error_code);
 366 }
 367
 368 /*
 369  * Initializes the mp_write_session. For such a session the new connection
 370  * would be opened. The data should be written to the session with
 371  * __cached_mp_write function. The __close_cached_mp_write_session function
 372  * should be used to submit session and __abandon_cached_mp_write_session - to
 373  * abandon it. When the session is submitted, the whole se
 374  */
 375 struct cached_connection_ *
 376 __open_cached_mp_write_session(struct cached_connection_params const *params,
 377     const char *entry_name)
 378 {
 379         struct cached_connection_ *connection, *retval;
 380         size_t name_size;
 381         int error_code;
 382         int result;
 383
 384         retval = NULL;
 385         connection = __open_cached_connection(params);
 386         if (connection == NULL)
 387                 return (NULL);
 388         connection->mp_flag = 1;
 389
 390         result = send_credentials(connection, CET_MP_WRITE_SESSION_REQUEST);
 391         if (result != 0)
 392                 goto fin;
 393
 394         name_size = strlen(entry_name);
 395         result = safe_write(connection, &name_size, sizeof(size_t));
 396         if (result != 0)
 397                 goto fin;
 398
 399         result = safe_write(connection, entry_name, name_size);
 400         if (result != 0)
 401                 goto fin;
 402
 403         result = safe_read(connection, &error_code, sizeof(int));
 404         if (result != 0)
 405                 goto fin;
 406
 407         if (error_code != 0)
 408                 result = error_code;
 409
 410 fin:
 411         if (result != 0)
 412                 __close_cached_connection(connection);
 413         else
 414                 retval = connection;
 415         return (retval);
 416 }
 417
 418 /*
 419  * Adds new portion of data to the opened write session
 420  */
 421 int
 422 __cached_mp_write(struct cached_connection_ *ws, const char *data,
 423     size_t data_size)
 424 {
 425         int request, result;
 426         int error_code;
 427
 428         error_code = -1;
 429
 430         request = CET_MP_WRITE_SESSION_WRITE_REQUEST;
 431         result = safe_write(ws, &request, sizeof(int));
 432         if (result != 0)
 433                 goto fin;
 434
 435         result = safe_write(ws, &data_size, sizeof(size_t));
 436         if (result != 0)
 437                 goto fin;
 438
 439         result = safe_write(ws, data, data_size);
 440         if (result != 0)
 441                 goto fin;
 442
 443         result = safe_read(ws, &error_code, sizeof(int));
 444         if (result != 0)
 445                 error_code = -1;
 446
 447 fin:
 448         return (error_code);
 449 }
 450
 451 /*
 452  * Abandons all operations with the write session. All data, that were written
 453  * to the session before, are discarded.
 454  */
 455 int
 456 __abandon_cached_mp_write_session(struct cached_connection_ *ws)
 457 {
 458         int notification;
 459         int result;
 460
 461         notification = CET_MP_WRITE_SESSION_ABANDON_NOTIFICATION;
 462         result = safe_write(ws, &notification, sizeof(int));
 463         __close_cached_connection(ws);
 464         return (result);
 465 }
 466
 467 /*
 468  * Gracefully closes the write session. The data, that were previously written
 469  * to the session, are committed.
 470  */
 471 int
 472 __close_cached_mp_write_session(struct cached_connection_ *ws)
 473 {
 474         int notification;
 475         int result __unused;
 476
 477         notification = CET_MP_WRITE_SESSION_CLOSE_NOTIFICATION;
 478         result = safe_write(ws, &notification, sizeof(int));
 479         __close_cached_connection(ws);
 480         return (0);
 481 }
 482
 483 struct cached_connection_ *
 484 __open_cached_mp_read_session(struct cached_connection_params const *params,
 485         const char *entry_name)
 486 {
 487         struct cached_connection_ *connection, *retval;
 488         size_t name_size;
 489         int error_code;
 490         int result;
 491
 492         retval = NULL;
 493         connection = __open_cached_connection(params);
 494         if (connection == NULL)
 495                 return (NULL);
 496         connection->mp_flag = 1;
 497
 498         result = send_credentials(connection, CET_MP_READ_SESSION_REQUEST);
 499         if (result != 0)
 500                 goto fin;
 501
 502         name_size = strlen(entry_name);
 503         result = safe_write(connection, &name_size, sizeof(size_t));
 504         if (result != 0)
 505                 goto fin;
 506
 507         result = safe_write(connection, entry_name, name_size);
 508         if (result != 0)
 509                 goto fin;
 510
 511         result = safe_read(connection, &error_code, sizeof(int));
 512         if (result != 0)
 513                 goto fin;
 514
 515         if (error_code != 0)
 516                 result = error_code;
 517
 518 fin:
 519         if (result != 0)
 520                 __close_cached_connection(connection);
 521         else
 522                 retval = connection;
 523         return (retval);
 524 }
 525
 526 int
 527 __cached_mp_read(struct cached_connection_ *rs, char *data, size_t *data_size)
 528 {
 529         size_t result_size;
 530         int error_code, rec_error_code;
 531         int request, result;
 532
 533         error_code = -1;
 534         request = CET_MP_READ_SESSION_READ_REQUEST;
 535         result = safe_write(rs, &request, sizeof(int));
 536         if (result != 0)
 537                 goto fin;
 538
 539         result = safe_read(rs, &rec_error_code, sizeof(int));
 540         if (result != 0)
 541                 goto fin;
 542
 543         if (rec_error_code != 0) {
 544                 error_code = rec_error_code;
 545                 goto fin;
 546         }
 547
 548         result = safe_read(rs, &result_size, sizeof(size_t));
 549         if (result != 0)
 550                 goto fin;
 551
 552         if (result_size > *data_size) {
 553                 *data_size = result_size;
 554                 error_code = -2;
 555                 goto fin;
 556         }
 557
 558         result = safe_read(rs, data, result_size);
 559         if (result != 0)
 560                 goto fin;
 561
 562         *data_size = result_size;
 563         error_code = 0;
 564
 565 fin:
 566         return (error_code);
 567 }
 568
 569 int
 570 __close_cached_mp_read_session(struct cached_connection_ *rs)
 571 {
 572
 573         __close_cached_connection(rs);
 574         return (0);
 575 }