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         /* channel used for communication between main
  97          * and connection handler threads */
  98         sdb_channel_t *chan;
  99 };
 100
 101 /*
 102  * connection management functions
 103  */
 104
 105 static int
 106 open_unix_sock(listener_t *listener)
 107 {
 108         struct sockaddr_un sa;
 109         int status;
 110
 111         listener->sock_fd = socket(AF_UNIX, SOCK_STREAM, 0);
 112         if (listener->sock_fd < 0) {
 113                 char buf[1024];
 114                 sdb_log(SDB_LOG_ERR, "frontend: Failed to open UNIX socket %s: %s",
 115                                 listener->address, sdb_strerror(errno, buf, sizeof(buf)));
 116                 return -1;
 117         }
 118
 119         memset(&sa, 0, sizeof(sa));
 120         sa.sun_family = AF_UNIX;
 121         strncpy(sa.sun_path, listener->address + strlen("unix:"),
 122                         sizeof(sa.sun_path));
 123
 124         status = bind(listener->sock_fd, (struct sockaddr *)&sa, sizeof(sa));
 125         if (status) {
 126                 char buf[1024];
 127                 sdb_log(SDB_LOG_ERR, "frontend: Failed to bind to UNIX socket %s: %s",
 128                                 listener->address, sdb_strerror(errno, buf, sizeof(buf)));
 129                 return -1;
 130         }
 131         return 0;
 132 } /* open_unix_sock */
 133
 134 /*
 135  * private variables
 136  */
 137
 138 /* the enum has to be sorted the same as the implementations array
 139  * to ensure that the type may be used as index into the array */
 140 enum {
 141         LISTENER_UNIXSOCK = 0,
 142 };
 143 static fe_listener_impl_t listener_impls[] = {
 144         { LISTENER_UNIXSOCK, "unix", open_unix_sock },
 145 };
 146
 147 /*
 148  * private helper functions
 149  */
 150
 151 static int
 152 get_type(const char *address)
 153 {
 154         char *sep;
 155         size_t len;
 156         size_t i;
 157
 158         sep = strchr(address, (int)':');
 159         if (! sep)
 160                 return -1;
 161
 162         assert(sep > address);
 163         len = (size_t)(sep - address);
 164
 165         for (i = 0; i < SDB_STATIC_ARRAY_LEN(listener_impls); ++i) {
 166                 fe_listener_impl_t *impl = listener_impls + i;
 167
 168                 if (!strncmp(address, impl->prefix, len)) {
 169                         assert(impl->type == (int)i);
 170                         return impl->type;
 171                 }
 172         }
 173         return -1;
 174 } /* get_type */
 175
 176 static void
 177 listener_destroy(listener_t *listener)
 178 {
 179         if (! listener)
 180                 return;
 181
 182         if (listener->sock_fd >= 0)
 183                 close(listener->sock_fd);
 184         listener->sock_fd = -1;
 185
 186         if (listener->address)
 187                 free(listener->address);
 188 } /* listener_destroy */
 189
 190 static listener_t *
 191 listener_create(sdb_fe_socket_t *sock, const char *address)
 192 {
 193         listener_t *listener;
 194         int type;
 195
 196         type = get_type(address);
 197         if (type < 0) {
 198                 sdb_log(SDB_LOG_ERR, "frontend: Unsupported address type specified "
 199                                 "in listen address '%s'", address);
 200                 return NULL;
 201         }
 202
 203         listener = realloc(sock->listeners,
 204                         sock->listeners_num * sizeof(*sock->listeners));
 205         if (! listener) {
 206                 char buf[1024];
 207                 sdb_log(SDB_LOG_ERR, "frontend: Failed to allocate memory: %s",
 208                                 sdb_strerror(errno, buf, sizeof(buf)));
 209                 return NULL;
 210         }
 211
 212         sock->listeners = listener;
 213         listener = sock->listeners + sock->listeners_num;
 214
 215         listener->sock_fd = -1;
 216         listener->address = strdup(address);
 217         if (! listener->address) {
 218                 char buf[1024];
 219                 sdb_log(SDB_LOG_ERR, "frontend: Failed to allocate memory: %s",
 220                                 sdb_strerror(errno, buf, sizeof(buf)));
 221                 listener_destroy(listener);
 222                 return NULL;
 223         }
 224         listener->type = type;
 225
 226         if (listener_impls[type].opener(listener)) {
 227                 /* prints error */
 228                 listener_destroy(listener);
 229                 return NULL;
 230         }
 231
 232         ++sock->listeners_num;
 233         return listener;
 234 } /* listener_create */
 235
 236 static int
 237 listener_listen(listener_t *listener)
 238 {
 239         assert(listener);
 240
 241         if (listen(listener->sock_fd, /* backlog = */ 32)) {
 242                 char buf[1024];
 243                 sdb_log(SDB_LOG_ERR, "frontend: Failed to listen on socket %s: %s",
 244                                 listener->address, sdb_strerror(errno, buf, sizeof(buf)));
 245                 return -1;
 246         }
 247         return 0;
 248 } /* listener_listen */
 249
 250 static void
 251 listener_close(listener_t *listener)
 252 {
 253         assert(listener);
 254
 255         if (listener->sock_fd < 0)
 256                 return;
 257
 258         close(listener->sock_fd);
 259         listener->sock_fd = -1;
 260 } /* listener_close */
 261
 262 static void
 263 socket_close(sdb_fe_socket_t *sock)
 264 {
 265         size_t i;
 266
 267         assert(sock);
 268         for (i = 0; i < sock->listeners_num; ++i)
 269                 listener_close(sock->listeners + i);
 270 } /* socket_close */
 271
 272 /*
 273  * private data types
 274  */
 275
 276 static int
 277 connection_init(sdb_object_t *obj, va_list ap)
 278 {
 279         connection_t *conn;
 280         int sock_fd;
 281         int sock_fl;
 282
 283         assert(obj);
 284         conn = &CONN(obj)->conn;
 285
 286         sock_fd = va_arg(ap, int);
 287
 288         conn->client_addr_len = sizeof(conn->client_addr);
 289         conn->fd = accept(sock_fd, (struct sockaddr *)&conn->client_addr,
 290                         &conn->client_addr_len);
 291
 292         if (conn->fd < 0) {
 293                 char buf[1024];
 294                 sdb_log(SDB_LOG_ERR, "frontend: Failed to accept remote "
 295                                 "connection: %s", sdb_strerror(errno,
 296                                         buf, sizeof(buf)));
 297                 return -1;
 298         }
 299
 300         if (conn->client_addr.ss_family != AF_UNIX) {
 301                 sdb_log(SDB_LOG_ERR, "frontend: Accepted connection using "
 302                                 "unexpected family type %d", conn->client_addr.ss_family);
 303                 return -1;
 304         }
 305
 306         sock_fl = fcntl(conn->fd, F_GETFL);
 307         if (fcntl(conn->fd, F_SETFL, sock_fl | O_NONBLOCK)) {
 308                 char buf[1024];
 309                 sdb_log(SDB_LOG_ERR, "frontend: Failed to switch connection conn#%i "
 310                                 "to non-blocking mode: %s", conn->fd,
 311                                 sdb_strerror(errno, buf, sizeof(buf)));
 312                 return -1;
 313         }
 314
 315         sdb_log(SDB_LOG_DEBUG, "frontend: Accepted connection on fd=%i",
 316                         conn->fd);
 317
 318         /* update the object name */
 319         snprintf(obj->name + strlen(CONN_FD_PREFIX),
 320                         strlen(CONN_FD_PLACEHOLDER), "%i", conn->fd);
 321         return 0;
 322 } /* connection_init */
 323
 324 static void
 325 connection_destroy(sdb_object_t *obj)
 326 {
 327         connection_t *conn;
 328
 329         assert(obj);
 330         conn = &CONN(obj)->conn;
 331
 332         sdb_log(SDB_LOG_DEBUG, "frontend: Closing connection on fd=%i", conn->fd);
 333         close(conn->fd);
 334         conn->fd = -1;
 335 } /* connection_destroy */
 336
 337 static sdb_type_t connection_type = {
 338         /* size = */ sizeof(connection_obj_t),
 339         /* init = */ connection_init,
 340         /* destroy = */ connection_destroy,
 341 };
 342
 343 /*
 344  * connection handler functions
 345  */
 346
 347 /* returns negative value on error, 0 on EOF, number of packets else */
 348 static int
 349 connection_read(int fd)
 350 {
 351         int n = 0;
 352
 353         while (42) {
 354                 int32_t cmd;
 355                 ssize_t status;
 356
 357                 errno = 0;
 358                 status = read(fd, &cmd, sizeof(cmd));
 359                 if (status < 0) {
 360                         if ((errno == EAGAIN) || (errno == EWOULDBLOCK))
 361                                 return n + 1;
 362                         return (int)status;
 363                 }
 364                 else if (! status) /* EOF */
 365                         return 0;
 366
 367                 /* XXX */
 368                 sdb_log(SDB_LOG_DEBUG, "frontend: read command %i from fd=%i",
 369                                 cmd, fd);
 370                 ++n;
 371         }
 372
 373         return n + 1;
 374 } /* connection_read */
 375
 376 static void *
 377 connection_handler(void *data)
 378 {
 379         sdb_fe_socket_t *sock = data;
 380
 381         assert(sock);
 382
 383         while (42) {
 384                 struct timespec timeout = { 0, 500000000 }; /* .5 seconds */
 385                 connection_obj_t *conn;
 386                 int status;
 387
 388                 errno = 0;
 389                 status = sdb_channel_select(sock->chan, /* read */ NULL, &conn,
 390                                 /* write */ NULL, NULL, &timeout);
 391                 if (status) {
 392                         char buf[1024];
 393
 394                         if (errno == ETIMEDOUT)
 395                                 continue;
 396                         if (errno == EBADF) /* channel shut down */
 397                                 break;
 398
 399                         sdb_log(SDB_LOG_ERR, "frontend: Failed to read from channel: %s",
 400                                         sdb_strerror(errno, buf, sizeof(buf)));
 401                         continue;
 402                 }
 403
 404                 status = connection_read(conn->conn.fd);
 405                 if (status <= 0) {
 406                         /* error or EOF -> close connection */
 407                         sdb_object_deref(SDB_OBJ(conn));
 408                 }
 409                 else {
 410                         if (sdb_llist_append(sock->open_connections, SDB_OBJ(conn))) {
 411                                 sdb_log(SDB_LOG_ERR, "frontend: Failed to re-append "
 412                                                 "connection %s to list of open connections",
 413                                                 SDB_OBJ(conn)->name);
 414                         }
 415
 416                         /* pass ownership back to list; or destroy in case of an error */
 417                         sdb_object_deref(SDB_OBJ(conn));
 418                 }
 419         }
 420         return NULL;
 421 } /* connection_handler */
 422
 423 static int
 424 connection_accept(sdb_fe_socket_t *sock, listener_t *listener)
 425 {
 426         sdb_object_t *obj;
 427
 428         /* the placeholder will be replaced with the accepted file
 429          * descriptor when initializing the object */
 430         obj = sdb_object_create(CONN_FD_PREFIX CONN_FD_PLACEHOLDER,
 431                         connection_type, listener->sock_fd);
 432         if (! obj)
 433                 return -1;
 434
 435         if (sdb_llist_append(sock->open_connections, obj)) {
 436                 sdb_log(SDB_LOG_ERR, "frontend: Failed to append "
 437                                 "connection %s to list of open connections",
 438                                 obj->name);
 439                 sdb_object_deref(obj);
 440                 return -1;
 441         }
 442
 443         /* hand ownership over to the list */
 444         sdb_object_deref(obj);
 445         return 0;
 446 } /* connection_accept */
 447
 448 /*
 449  * public API
 450  */
 451
 452 sdb_fe_socket_t *
 453 sdb_fe_sock_create(void)
 454 {
 455         sdb_fe_socket_t *sock;
 456
 457         sock = calloc(1, sizeof(*sock));
 458         if (! sock)
 459                 return NULL;
 460
 461         sock->open_connections = sdb_llist_create();
 462         if (! sock->open_connections) {
 463                 sdb_fe_sock_destroy(sock);
 464                 return NULL;
 465         }
 466         return sock;
 467 } /* sdb_fe_sock_create */
 468
 469 void
 470 sdb_fe_sock_destroy(sdb_fe_socket_t *sock)
 471 {
 472         size_t i;
 473
 474         if (! sock)
 475                 return;
 476
 477         for (i = 0; i < sock->listeners_num; ++i) {
 478                 listener_destroy(sock->listeners + i);
 479         }
 480         if (sock->listeners)
 481                 free(sock->listeners);
 482         sock->listeners = NULL;
 483
 484         sdb_llist_destroy(sock->open_connections);
 485         sock->open_connections = NULL;
 486         free(sock);
 487 } /* sdb_fe_sock_destroy */
 488
 489 int
 490 sdb_fe_sock_add_listener(sdb_fe_socket_t *sock, const char *address)
 491 {
 492         listener_t *listener;
 493
 494         if ((! sock) || (! address))
 495                 return -1;
 496
 497         listener = listener_create(sock, address);
 498         if (! listener)
 499                 return -1;
 500         return 0;
 501 } /* sdb_fe_sock_add_listener */
 502
 503 int
 504 sdb_fe_sock_listen_and_serve(sdb_fe_socket_t *sock, sdb_fe_loop_t *loop)
 505 {
 506         fd_set sockets;
 507         int max_listen_fd = 0;
 508         size_t i;
 509
 510         /* XXX: make the number of threads configurable */
 511         pthread_t handler_threads[5];
 512
 513         if ((! sock) || (! sock->listeners_num) || (! loop) || sock->chan)
 514                 return -1;
 515
 516         FD_ZERO(&sockets);
 517         for (i = 0; i < sock->listeners_num; ++i) {
 518                 listener_t *listener = sock->listeners + i;
 519
 520                 if (listener_listen(listener)) {
 521                         socket_close(sock);
 522                         return -1;
 523                 }
 524
 525                 FD_SET(listener->sock_fd, &sockets);
 526                 if (listener->sock_fd > max_listen_fd)
 527                         max_listen_fd = listener->sock_fd;
 528         }
 529
 530         sock->chan = sdb_channel_create(1024, sizeof(connection_obj_t *));
 531         if (! sock->chan) {
 532                 socket_close(sock);
 533                 return -1;
 534         }
 535
 536         memset(&handler_threads, 0, sizeof(handler_threads));
 537         /* XXX: error handling */
 538         for (i = 0; i < SDB_STATIC_ARRAY_LEN(handler_threads); ++i)
 539                 pthread_create(&handler_threads[i], /* attr = */ NULL,
 540                                 connection_handler, /* arg = */ sock);
 541
 542         while (loop->do_loop) {
 543                 fd_set ready;
 544                 fd_set exceptions;
 545                 int max_fd;
 546                 int n;
 547
 548                 struct timeval timeout = { 1, 0 }; /* one second */
 549                 sdb_llist_iter_t *iter;
 550
 551                 FD_ZERO(&ready);
 552                 FD_ZERO(&exceptions);
 553
 554                 ready = sockets;
 555
 556                 max_fd = max_listen_fd;
 557
 558                 iter = sdb_llist_get_iter(sock->open_connections);
 559                 if (! iter) {
 560                         sdb_log(SDB_LOG_ERR, "frontend: Failed to acquire iterator "
 561                                         "for open connections");
 562                         break;
 563                 }
 564
 565                 while (sdb_llist_iter_has_next(iter)) {
 566                         sdb_object_t *obj = sdb_llist_iter_get_next(iter);
 567                         FD_SET(CONN(obj)->conn.fd, &ready);
 568                         FD_SET(CONN(obj)->conn.fd, &exceptions);
 569
 570                         if (CONN(obj)->conn.fd > max_fd)
 571                                 max_fd = CONN(obj)->conn.fd;
 572                 }
 573                 sdb_llist_iter_destroy(iter);
 574
 575                 errno = 0;
 576                 n = select(max_fd + 1, &ready, NULL, &exceptions, &timeout);
 577                 if (n < 0) {
 578                         char buf[1024];
 579
 580                         if (errno == EINTR)
 581                                 continue;
 582
 583                         sdb_log(SDB_LOG_ERR, "frontend: Failed to monitor sockets: %s",
 584                                         sdb_strerror(errno, buf, sizeof(buf)));
 585                         break;
 586                 }
 587
 588                 if (! n)
 589                         continue;
 590
 591                 for (i = 0; i < sock->listeners_num; ++i) {
 592                         listener_t *listener = sock->listeners + i;
 593                         if (FD_ISSET(listener->sock_fd, &ready))
 594                                 if (connection_accept(sock, listener))
 595                                         continue;
 596                 }
 597
 598                 iter = sdb_llist_get_iter(sock->open_connections);
 599                 if (! iter) {
 600                         sdb_log(SDB_LOG_ERR, "frontend: Failed to acquire iterator "
 601                                         "for open connections");
 602                         break;
 603                 }
 604
 605                 while (sdb_llist_iter_has_next(iter)) {
 606                         sdb_object_t *obj = sdb_llist_iter_get_next(iter);
 607
 608                         if (FD_ISSET(CONN(obj)->conn.fd, &exceptions))
 609                                 sdb_log(SDB_LOG_INFO, "Exception on fd %d",
 610                                                 CONN(obj)->conn.fd);
 611
 612                         if (FD_ISSET(CONN(obj)->conn.fd, &ready)) {
 613                                 sdb_llist_iter_remove_current(iter);
 614                                 sdb_channel_write(sock->chan, &obj);
 615                         }
 616                 }
 617                 sdb_llist_iter_destroy(iter);
 618         }
 619
 620         socket_close(sock);
 621
 622         sdb_log(SDB_LOG_INFO, "frontend: Waiting for connection handler threads "
 623                         "to terminate");
 624         if (! sdb_channel_shutdown(sock->chan))
 625                 for (i = 0; i < SDB_STATIC_ARRAY_LEN(handler_threads); ++i)
 626                         pthread_join(handler_threads[i], NULL);
 627         /* else: we tried our best; let the operating system clean up */
 628
 629         sdb_channel_destroy(sock->chan);
 630         sock->chan = NULL;
 631         return 0;
 632 } /* sdb_fe_sock_listen_and_server */
 633
 634 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */
 635