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