src/frontend/sock.c

   1 /*
   2  * SysDB - src/frontend/sock.c
   3  * Copyright (C) 2013 Sebastian 'tokkee' Harl <sh@tokkee.org>
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  16  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  17  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  18  * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR
  19  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  20  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  21  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
  22  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  23  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  24  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  25  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  26  */
  27
  28 #include "sysdb.h"
  29 #include "core/error.h"
  30 #include "core/object.h"
  31 #include "frontend/sock.h"
  32
  33 #include "utils/channel.h"
  34 #include "utils/llist.h"
  35
  36 #include <assert.h>
  37
  38 #include <errno.h>
  39
  40 #include <stdio.h>
  41 #include <stdlib.h>
  42 #include <string.h>
  43
  44 #include <unistd.h>
  45
  46 #include <fcntl.h>
  47
  48 #include <sys/time.h>
  49 #include <sys/types.h>
  50 #include <sys/select.h>
  51 #include <sys/socket.h>
  52 #include <sys/un.h>
  53
  54 #include <pthread.h>
  55
  56 /* name of connection objects */
  57 #define CONN_FD_PREFIX "conn#"
  58 #define CONN_FD_PLACEHOLDER "XXXXXXX"
  59
  60 /*
  61  * private data types
  62  */
  63
  64 typedef struct {
  65         int fd;
  66         struct sockaddr_storage client_addr;
  67         socklen_t client_addr_len;
  68 } connection_t;
  69
  70 typedef struct {
  71         sdb_object_t super;
  72         connection_t conn;
  73 } connection_obj_t;
  74 #define CONN(obj) ((connection_obj_t *)(obj))
  75
  76 typedef struct {
  77         char *address;
  78         int   type;
  79
  80         int sock_fd;
  81 } listener_t;
  82
  83 typedef struct {
  84         int type;
  85         const char *prefix;
  86
  87         int (*opener)(listener_t *);
  88 } fe_listener_impl_t;
  89
  90 struct sdb_fe_socket {
  91         listener_t *listeners;
  92         size_t listeners_num;
  93
  94         sdb_llist_t *open_connections;
  95 };
  96
  97 /*
  98  * connection management functions
  99  */
 100
 101 static int
 102 open_unix_sock(listener_t *listener)
 103 {
 104         struct sockaddr_un sa;
 105         int status;
 106
 107         listener->sock_fd = socket(AF_UNIX, SOCK_STREAM, 0);
 108         if (listener->sock_fd < 0) {
 109                 char buf[1024];
 110                 sdb_log(SDB_LOG_ERR, "frontend: Failed to open UNIX socket %s: %s",
 111                                 listener->address, sdb_strerror(errno, buf, sizeof(buf)));
 112                 return -1;
 113         }
 114
 115         memset(&sa, 0, sizeof(sa));
 116         sa.sun_family = AF_UNIX;
 117         strncpy(sa.sun_path, listener->address + strlen("unix:"),
 118                         sizeof(sa.sun_path));
 119
 120         status = bind(listener->sock_fd, (struct sockaddr *)&sa, sizeof(sa));
 121         if (status) {
 122                 char buf[1024];
 123                 sdb_log(SDB_LOG_ERR, "frontend: Failed to bind to UNIX socket %s: %s",
 124                                 listener->address, sdb_strerror(errno, buf, sizeof(buf)));
 125                 return -1;
 126         }
 127         return 0;
 128 } /* open_unix_sock */
 129
 130 /*
 131  * private variables
 132  */
 133
 134 /* the enum has to be sorted the same as the implementations array
 135  * to ensure that the type may be used as index into the array */
 136 enum {
 137         LISTENER_UNIXSOCK = 0,
 138 };
 139 static fe_listener_impl_t listener_impls[] = {
 140         { LISTENER_UNIXSOCK, "unix", open_unix_sock },
 141 };
 142
 143 /*
 144  * private helper functions
 145  */
 146
 147 static int
 148 get_type(const char *address)
 149 {
 150         char *sep;
 151         size_t len;
 152         size_t i;
 153
 154         sep = strchr(address, (int)':');
 155         if (! sep)
 156                 return -1;
 157
 158         assert(sep > address);
 159         len = (size_t)(sep - address);
 160
 161         for (i = 0; i < SDB_STATIC_ARRAY_LEN(listener_impls); ++i) {
 162                 fe_listener_impl_t *impl = listener_impls + i;
 163
 164                 if (!strncmp(address, impl->prefix, len)) {
 165                         assert(impl->type == (int)i);
 166                         return impl->type;
 167                 }
 168         }
 169         return -1;
 170 } /* get_type */
 171
 172 static void
 173 listener_destroy(listener_t *listener)
 174 {
 175         if (! listener)
 176                 return;
 177
 178         if (listener->sock_fd >= 0)
 179                 close(listener->sock_fd);
 180
 181         if (listener->address)
 182                 free(listener->address);
 183 } /* listener_destroy */
 184
 185 static listener_t *
 186 listener_create(sdb_fe_socket_t *sock, const char *address)
 187 {
 188         listener_t *listener;
 189         int type;
 190
 191         type = get_type(address);
 192         if (type < 0) {
 193                 sdb_log(SDB_LOG_ERR, "frontend: Unsupported address type specified "
 194                                 "in listen address '%s'", address);
 195                 return NULL;
 196         }
 197
 198         listener = realloc(sock->listeners,
 199                         sock->listeners_num * sizeof(*sock->listeners));
 200         if (! listener) {
 201                 char buf[1024];
 202                 sdb_log(SDB_LOG_ERR, "frontend: Failed to allocate memory: %s",
 203                                 sdb_strerror(errno, buf, sizeof(buf)));
 204                 return NULL;
 205         }
 206
 207         sock->listeners = listener;
 208         listener = sock->listeners + sock->listeners_num;
 209
 210         listener->sock_fd = -1;
 211         listener->address = strdup(address);
 212         if (! listener->address) {
 213                 char buf[1024];
 214                 sdb_log(SDB_LOG_ERR, "frontend: Failed to allocate memory: %s",
 215                                 sdb_strerror(errno, buf, sizeof(buf)));
 216                 listener_destroy(listener);
 217                 return NULL;
 218         }
 219         listener->type = type;
 220
 221         if (listener_impls[type].opener(listener)) {
 222                 /* prints error */
 223                 listener_destroy(listener);
 224                 return NULL;
 225         }
 226
 227         ++sock->listeners_num;
 228         return listener;
 229 } /* listener_create */
 230
 231 /*
 232  * private data types
 233  */
 234
 235 static int
 236 connection_init(sdb_object_t *obj, va_list ap)
 237 {
 238         connection_t *conn;
 239         int sock_fd;
 240         int sock_fl;
 241
 242         assert(obj);
 243         conn = &CONN(obj)->conn;
 244
 245         sock_fd = va_arg(ap, int);
 246
 247         conn->client_addr_len = sizeof(conn->client_addr);
 248         conn->fd = accept(sock_fd, (struct sockaddr *)&conn->client_addr,
 249                         &conn->client_addr_len);
 250
 251         if (conn->fd < 0) {
 252                 char buf[1024];
 253                 sdb_log(SDB_LOG_ERR, "frontend: Failed to accept remote "
 254                                 "connection: %s", sdb_strerror(errno,
 255                                         buf, sizeof(buf)));
 256                 return -1;
 257         }
 258
 259         if (conn->client_addr.ss_family != AF_UNIX) {
 260                 sdb_log(SDB_LOG_ERR, "frontend: Accepted connection using "
 261                                 "unexpected family type %d", conn->client_addr.ss_family);
 262                 return -1;
 263         }
 264
 265         sock_fl = fcntl(conn->fd, F_GETFL);
 266         if (fcntl(conn->fd, F_SETFL, sock_fl | O_NONBLOCK)) {
 267                 char buf[1024];
 268                 sdb_log(SDB_LOG_ERR, "frontend: Failed to switch connection conn#%i "
 269                                 "to non-blocking mode: %s", conn->fd,
 270                                 sdb_strerror(errno, buf, sizeof(buf)));
 271                 return -1;
 272         }
 273
 274         sdb_log(SDB_LOG_DEBUG, "frontend: Accepted connection on fd=%i",
 275                         conn->fd);
 276
 277         /* update the object name */
 278         snprintf(obj->name + strlen(CONN_FD_PREFIX),
 279                         strlen(CONN_FD_PLACEHOLDER), "%i", conn->fd);
 280         return 0;
 281 } /* connection_init */
 282
 283 static void
 284 connection_destroy(sdb_object_t *obj)
 285 {
 286         connection_t *conn;
 287
 288         assert(obj);
 289         conn = &CONN(obj)->conn;
 290
 291         close(conn->fd);
 292         conn->fd = -1;
 293 } /* connection_destroy */
 294
 295 static sdb_type_t connection_type = {
 296         /* size = */ sizeof(connection_obj_t),
 297         /* init = */ connection_init,
 298         /* destroy = */ connection_destroy,
 299 };
 300
 301 /*
 302  * connection handler functions
 303  */
 304
 305 static void *
 306 connection_handler(void *data)
 307 {
 308         sdb_channel_t *chan = data;
 309
 310         assert(chan);
 311
 312         while (42) {
 313                 struct timespec timeout = { 0, 500000000 }; /* .5 seconds */
 314                 connection_obj_t *conn;
 315                 int status;
 316
 317                 errno = 0;
 318                 status = sdb_channel_select(chan, NULL, &conn, NULL, NULL, &timeout);
 319                 if (status) {
 320                         char buf[1024];
 321
 322                         if (errno == ETIMEDOUT)
 323                                 continue;
 324                         if (errno == EBADF) /* channel shut down */
 325                                 break;
 326
 327                         sdb_log(SDB_LOG_ERR, "frontend: Failed to read from channel: %s",
 328                                         sdb_strerror(errno, buf, sizeof(buf)));
 329                         continue;
 330                 }
 331
 332                 /* XXX */
 333                 sdb_log(SDB_LOG_INFO, "frontend: Data available on connection fd=%i\n",
 334                                 conn->conn.fd);
 335         }
 336         return NULL;
 337 } /* connection_handler */
 338
 339 static int
 340 connection_accept(sdb_fe_socket_t *sock, listener_t *listener)
 341 {
 342         sdb_object_t *obj;
 343
 344         /* the placeholder will be replaced with the accepted file
 345          * descriptor when initializing the object */
 346         obj = sdb_object_create(CONN_FD_PREFIX CONN_FD_PLACEHOLDER,
 347                         connection_type, listener->sock_fd);
 348         if (! obj)
 349                 return -1;
 350
 351         if (sdb_llist_append(sock->open_connections, obj)) {
 352                 sdb_log(SDB_LOG_ERR, "frontend: Failed to append "
 353                                 "connection %s to list of open connections",
 354                                 obj->name);
 355                 sdb_object_deref(obj);
 356                 return -1;
 357         }
 358
 359         /* hand ownership over to the list */
 360         sdb_object_deref(obj);
 361         return 0;
 362 } /* connection_accept */
 363
 364 /*
 365  * public API
 366  */
 367
 368 sdb_fe_socket_t *
 369 sdb_fe_sock_create(void)
 370 {
 371         sdb_fe_socket_t *sock;
 372
 373         sock = calloc(1, sizeof(*sock));
 374         if (! sock)
 375                 return NULL;
 376
 377         sock->open_connections = sdb_llist_create();
 378         if (! sock->open_connections) {
 379                 sdb_fe_sock_destroy(sock);
 380                 return NULL;
 381         }
 382         return sock;
 383 } /* sdb_fe_sock_create */
 384
 385 void
 386 sdb_fe_sock_destroy(sdb_fe_socket_t *sock)
 387 {
 388         size_t i;
 389
 390         if (! sock)
 391                 return;
 392
 393         for (i = 0; i < sock->listeners_num; ++i) {
 394                 listener_destroy(sock->listeners + i);
 395         }
 396         if (sock->listeners)
 397                 free(sock->listeners);
 398         sock->listeners = NULL;
 399
 400         sdb_llist_destroy(sock->open_connections);
 401         sock->open_connections = NULL;
 402         free(sock);
 403 } /* sdb_fe_sock_destroy */
 404
 405 int
 406 sdb_fe_sock_add_listener(sdb_fe_socket_t *sock, const char *address)
 407 {
 408         listener_t *listener;
 409
 410         if ((! sock) || (! address))
 411                 return -1;
 412
 413         listener = listener_create(sock, address);
 414         if (! listener)
 415                 return -1;
 416         return 0;
 417 } /* sdb_fe_sock_add_listener */
 418
 419 int
 420 sdb_fe_sock_listen_and_serve(sdb_fe_socket_t *sock, sdb_fe_loop_t *loop)
 421 {
 422         sdb_channel_t *chan;
 423         fd_set sockets;
 424         int max_listen_fd = 0;
 425         size_t i;
 426
 427         /* XXX: make the number of threads configurable */
 428         pthread_t handler_threads[5];
 429
 430         if ((! sock) || (! sock->listeners_num) || (! loop))
 431                 return -1;
 432
 433         FD_ZERO(&sockets);
 434
 435         for (i = 0; i < sock->listeners_num; ++i) {
 436                 listener_t *listener = sock->listeners + i;
 437
 438                 if (listen(listener->sock_fd, /* backlog = */ 32)) {
 439                         char buf[1024];
 440                         sdb_log(SDB_LOG_ERR, "frontend: Failed to listen on socket %s: %s",
 441                                         listener->address, sdb_strerror(errno, buf, sizeof(buf)));
 442                         return -1;
 443                 }
 444
 445                 FD_SET(listener->sock_fd, &sockets);
 446                 if (listener->sock_fd > max_listen_fd)
 447                         max_listen_fd = listener->sock_fd;
 448         }
 449
 450         chan = sdb_channel_create(1024, sizeof(connection_obj_t *));
 451         if (! chan)
 452                 return -1;
 453
 454         memset(&handler_threads, 0, sizeof(handler_threads));
 455         /* XXX: error handling */
 456         for (i = 0; i < SDB_STATIC_ARRAY_LEN(handler_threads); ++i)
 457                 pthread_create(&handler_threads[i], /* attr = */ NULL,
 458                                 connection_handler, /* arg = */ chan);
 459
 460         while (loop->do_loop) {
 461                 fd_set ready;
 462                 fd_set exceptions;
 463                 int max_fd;
 464                 int n;
 465
 466                 struct timeval timeout = { 1, 0 }; /* one second */
 467                 sdb_llist_iter_t *iter;
 468
 469                 FD_ZERO(&ready);
 470                 FD_ZERO(&exceptions);
 471
 472                 ready = sockets;
 473
 474                 max_fd = max_listen_fd;
 475
 476                 iter = sdb_llist_get_iter(sock->open_connections);
 477                 if (! iter) {
 478                         sdb_log(SDB_LOG_ERR, "frontend: Failed to acquire iterator "
 479                                         "for open connections");
 480                         return -1;
 481                 }
 482
 483                 while (sdb_llist_iter_has_next(iter)) {
 484                         sdb_object_t *obj = sdb_llist_iter_get_next(iter);
 485                         FD_SET(CONN(obj)->conn.fd, &ready);
 486                         FD_SET(CONN(obj)->conn.fd, &exceptions);
 487
 488                         if (CONN(obj)->conn.fd > max_fd)
 489                                 max_fd = CONN(obj)->conn.fd;
 490                 }
 491                 sdb_llist_iter_destroy(iter);
 492
 493                 errno = 0;
 494                 n = select(max_fd + 1, &ready, NULL, &exceptions, &timeout);
 495                 if (n < 0) {
 496                         char buf[1024];
 497
 498                         if (errno == EINTR)
 499                                 continue;
 500
 501                         sdb_log(SDB_LOG_ERR, "frontend: Failed to monitor sockets: %s",
 502                                         sdb_strerror(errno, buf, sizeof(buf)));
 503                         return -1;
 504                 }
 505
 506                 if (! n)
 507                         continue;
 508
 509                 for (i = 0; i < sock->listeners_num; ++i) {
 510                         listener_t *listener = sock->listeners + i;
 511                         if (FD_ISSET(listener->sock_fd, &ready))
 512                                 if (connection_accept(sock, listener))
 513                                         continue;
 514                 }
 515
 516                 iter = sdb_llist_get_iter(sock->open_connections);
 517                 if (! iter) {
 518                         sdb_log(SDB_LOG_ERR, "frontend: Failed to acquire iterator "
 519                                         "for open connections");
 520                         return -1;
 521                 }
 522
 523                 while (sdb_llist_iter_has_next(iter)) {
 524                         sdb_object_t *obj = sdb_llist_iter_get_next(iter);
 525
 526                         if (FD_ISSET(CONN(obj)->conn.fd, &exceptions))
 527                                 sdb_log(SDB_LOG_INFO, "Exception on fd %d",
 528                                                 CONN(obj)->conn.fd);
 529
 530                         if (FD_ISSET(CONN(obj)->conn.fd, &ready)) {
 531                                 sdb_log(SDB_LOG_INFO, "Data on fd %d", CONN(obj)->conn.fd);
 532                                 sdb_llist_iter_remove_current(iter);
 533                                 sdb_channel_write(chan, &obj);
 534                         }
 535                 }
 536                 sdb_llist_iter_destroy(iter);
 537         }
 538
 539         sdb_log(SDB_LOG_INFO, "frontend: Waiting for connection handler threads "
 540                         "to terminate");
 541         if (! sdb_channel_shutdown(chan))
 542                 for (i = 0; i < SDB_STATIC_ARRAY_LEN(handler_threads); ++i)
 543                         pthread_join(handler_threads[i], NULL);
 544         /* else: we tried our best; let the operating system clean up */
 545         return 0;
 546 } /* sdb_fe_sock_listen_and_server */
 547
 548 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */
 549