src/frontend/connection.c

   1 /*
   2  * SysDB - src/frontend/connection.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 #ifdef HAVE_CONFIG_H
  29 #       include "config.h"
  30 #endif
  31
  32 #include "sysdb.h"
  33 #include "core/object.h"
  34 #include "core/plugin.h"
  35 #include "frontend/connection-private.h"
  36 #include "utils/error.h"
  37 #include "utils/strbuf.h"
  38 #include "utils/proto.h"
  39 #include "utils/os.h"
  40
  41 #include <assert.h>
  42 #include <errno.h>
  43
  44 #include <arpa/inet.h>
  45 #include <fcntl.h>
  46
  47 #include <sys/socket.h>
  48 #include <sys/un.h>
  49
  50 #include <stdlib.h>
  51 #include <string.h>
  52
  53 #include <pthread.h>
  54 #include <netdb.h>
  55
  56 /*
  57  * private variables
  58  */
  59
  60 static pthread_key_t conn_ctx_key;
  61 static bool          conn_ctx_key_initialized = 0;
  62
  63 /*
  64  * private types
  65  */
  66
  67 /* name of connection objects */
  68 #define CONN_FD_PREFIX "conn#"
  69 #define CONN_FD_PLACEHOLDER "XXXXXXX"
  70
  71 static ssize_t
  72 conn_read(sdb_conn_t *conn, size_t len)
  73 {
  74         return sdb_strbuf_read(conn->buf, conn->fd, len);
  75 } /* conn_read */
  76
  77 static ssize_t
  78 conn_write(sdb_conn_t *conn, const void *buf, size_t len)
  79 {
  80         return sdb_write(conn->fd, len, buf);
  81 } /* conn_write */
  82
  83 static int
  84 connection_init(sdb_object_t *obj, va_list ap)
  85 {
  86         sdb_conn_t *conn;
  87         int sock_fd;
  88         int sock_fl;
  89
  90         assert(obj);
  91         conn = CONN(obj);
  92
  93         sock_fd = va_arg(ap, int);
  94
  95         conn->buf = sdb_strbuf_create(/* size = */ 128);
  96         if (! conn->buf) {
  97                 sdb_log(SDB_LOG_ERR, "frontend: Failed to allocate a read buffer "
  98                                 "for a new connection");
  99                 return -1;
 100         }
 101         conn->errbuf = sdb_strbuf_create(0);
 102         if (! conn->errbuf) {
 103                 sdb_log(SDB_LOG_ERR, "frontend: Failed to allocate an error buffer "
 104                                 "for a new connection");
 105                 return -1;
 106         }
 107
 108         conn->client_addr_len = sizeof(conn->client_addr);
 109         conn->fd = accept(sock_fd, (struct sockaddr *)&conn->client_addr,
 110                         &conn->client_addr_len);
 111
 112         if (conn->fd < 0) {
 113                 char buf[1024];
 114                 sdb_log(SDB_LOG_ERR, "frontend: Failed to accept remote "
 115                                 "connection: %s", sdb_strerror(errno,
 116                                         buf, sizeof(buf)));
 117                 return -1;
 118         }
 119
 120         /* update the object name */
 121         snprintf(obj->name + strlen(CONN_FD_PREFIX),
 122                         strlen(CONN_FD_PLACEHOLDER), "%i", conn->fd);
 123
 124         /* defaults */
 125         conn->read = conn_read;
 126         conn->write = conn_write;
 127         conn->finish = NULL;
 128         conn->ssl_session = NULL;
 129
 130         sock_fl = fcntl(conn->fd, F_GETFL);
 131         if (fcntl(conn->fd, F_SETFL, sock_fl | O_NONBLOCK)) {
 132                 char buf[1024];
 133                 sdb_log(SDB_LOG_ERR, "frontend: Failed to switch connection conn#%i "
 134                                 "to non-blocking mode: %s", conn->fd,
 135                                 sdb_strerror(errno, buf, sizeof(buf)));
 136                 return -1;
 137         }
 138
 139         conn->username = NULL;
 140         conn->ready = 0;
 141
 142         sdb_log(SDB_LOG_DEBUG, "frontend: Accepted connection on fd=%i",
 143                         conn->fd);
 144
 145         conn->cmd = SDB_CONNECTION_IDLE;
 146         conn->cmd_len = 0;
 147         conn->skip_len = 0;
 148         return 0;
 149 } /* connection_init */
 150
 151 static void
 152 connection_destroy(sdb_object_t *obj)
 153 {
 154         sdb_conn_t *conn;
 155         size_t len;
 156
 157         assert(obj);
 158         conn = CONN(obj);
 159
 160         conn->ready = 0;
 161
 162         if (conn->finish)
 163                 conn->finish(conn);
 164         conn->finish = NULL;
 165
 166         if (conn->buf) {
 167                 len = sdb_strbuf_len(conn->buf);
 168                 if (len)
 169                         sdb_log(SDB_LOG_INFO, "frontend: Discarding incomplete command "
 170                                         "(%zu byte%s left in buffer)", len, len == 1 ? "" : "s");
 171         }
 172
 173         sdb_log(SDB_LOG_DEBUG, "frontend: Closing connection %s", obj->name);
 174         sdb_connection_close(conn);
 175
 176         if (conn->username)
 177                 free(conn->username);
 178         conn->username = NULL;
 179
 180         sdb_strbuf_destroy(conn->buf);
 181         conn->buf = NULL;
 182         sdb_strbuf_destroy(conn->errbuf);
 183         conn->errbuf = NULL;
 184 } /* connection_destroy */
 185
 186 static sdb_type_t connection_type = {
 187         /* size = */ sizeof(sdb_conn_t),
 188         /* init = */ connection_init,
 189         /* destroy = */ connection_destroy,
 190 };
 191
 192 /*
 193  * private helper functions
 194  */
 195
 196 static void
 197 sdb_conn_ctx_destructor(void *c)
 198 {
 199         sdb_object_t *conn = c;
 200
 201         if (! conn)
 202                 return;
 203         sdb_object_deref(conn);
 204 } /* sdb_conn_ctx_destructor */
 205
 206 static void
 207 sdb_conn_ctx_init(void)
 208 {
 209         if (conn_ctx_key_initialized)
 210                 return;
 211
 212         pthread_key_create(&conn_ctx_key, sdb_conn_ctx_destructor);
 213         conn_ctx_key_initialized = 1;
 214 } /* sdb_conn_ctx_init */
 215
 216 static void
 217 sdb_conn_set_ctx(sdb_conn_t *conn)
 218 {
 219         sdb_conn_t *old;
 220
 221         sdb_conn_ctx_init();
 222
 223         old = pthread_getspecific(conn_ctx_key);
 224         if (old)
 225                 sdb_object_deref(SDB_OBJ(old));
 226         if (conn)
 227                 sdb_object_ref(SDB_OBJ(conn));
 228         pthread_setspecific(conn_ctx_key, conn);
 229 } /* sdb_conn_set_ctx */
 230
 231 static sdb_conn_t *
 232 sdb_conn_get_ctx(void)
 233 {
 234         if (! conn_ctx_key_initialized)
 235                 return NULL;
 236         return pthread_getspecific(conn_ctx_key);
 237 } /* sdb_conn_get_ctx */
 238
 239 /*
 240  * connection handler functions
 241  */
 242
 243 /*
 244  * connection_log:
 245  * Send a log message originating from the current thread to the client.
 246  */
 247 static int
 248 connection_log(int prio, const char *msg,
 249                 sdb_object_t __attribute__((unused)) *user_data)
 250 {
 251         uint32_t len = (uint32_t)sizeof(uint32_t) + (uint32_t)strlen(msg);
 252         uint32_t p = htonl((uint32_t)prio);
 253         char tmp[len + 1];
 254
 255         sdb_conn_t *conn;
 256
 257         conn = sdb_conn_get_ctx();
 258         /* no connection associated to this thread
 259          * or startup not done yet => don't leak any information */
 260         if ((! conn) || (! conn->ready))
 261                 return 0;
 262
 263         /* XXX: make the log-level configurable by the client at runtime */
 264         if (prio >= SDB_LOG_DEBUG)
 265                 return 0;
 266
 267         memcpy(tmp, &p, sizeof(p));
 268         strcpy(tmp + sizeof(p), msg);
 269
 270         if (sdb_connection_send(conn, SDB_CONNECTION_LOG, len, tmp) < 0)
 271                 return -1;
 272         return 0;
 273 } /* connection_log */
 274
 275 static int
 276 command_handle(sdb_conn_t *conn)
 277 {
 278         int status = -1;
 279
 280         assert(conn && (conn->cmd != SDB_CONNECTION_IDLE));
 281         assert(! conn->skip_len);
 282
 283         if (conn->cmd == SDB_CONNECTION_PING)
 284                 status = sdb_connection_ping(conn);
 285         else if (conn->cmd == SDB_CONNECTION_STARTUP)
 286                 status = sdb_fe_session_start(conn);
 287
 288         else if (conn->cmd == SDB_CONNECTION_QUERY)
 289                 status = sdb_fe_query(conn);
 290         else if (conn->cmd == SDB_CONNECTION_FETCH)
 291                 status = sdb_fe_fetch(conn);
 292         else if (conn->cmd == SDB_CONNECTION_LIST)
 293                 status = sdb_fe_list(conn);
 294         else if (conn->cmd == SDB_CONNECTION_LOOKUP)
 295                 status = sdb_fe_lookup(conn);
 296         else if (conn->cmd == SDB_CONNECTION_STORE)
 297                 status = sdb_fe_store(conn);
 298
 299         else if (conn->cmd == SDB_CONNECTION_SERVER_VERSION)
 300                 status = sdb_connection_server_version(conn);
 301
 302         else {
 303                 sdb_log(SDB_LOG_WARNING, "frontend: Ignoring invalid command %#x",
 304                                 conn->cmd);
 305                 sdb_strbuf_sprintf(conn->errbuf, "Invalid command %#x", conn->cmd);
 306                 status = -1;
 307         }
 308
 309         if (status) {
 310                 if (! sdb_strbuf_len(conn->errbuf))
 311                         sdb_strbuf_sprintf(conn->errbuf, "Failed to execute command");
 312                 sdb_connection_send(conn, SDB_CONNECTION_ERROR,
 313                                 (uint32_t)sdb_strbuf_len(conn->errbuf),
 314                                 sdb_strbuf_string(conn->errbuf));
 315         }
 316         return status;
 317 } /* command_handle */
 318
 319 /* initialize the connection state information */
 320 static int
 321 command_init(sdb_conn_t *conn)
 322 {
 323         const char *errmsg = NULL;
 324
 325         assert(conn && (conn->cmd == SDB_CONNECTION_IDLE) && (! conn->cmd_len));
 326
 327         if (conn->skip_len)
 328                 return -1;
 329
 330         /* reset */
 331         sdb_strbuf_clear(conn->errbuf);
 332
 333         if (sdb_proto_unmarshal_header(SDB_STRBUF_STR(conn->buf),
 334                                 &conn->cmd, &conn->cmd_len) < 0)
 335                 return -1;
 336         sdb_strbuf_skip(conn->buf, 0, 2 * sizeof(uint32_t));
 337
 338         if ((! conn->ready) && (conn->cmd != SDB_CONNECTION_STARTUP))
 339                 errmsg = "Authentication required";
 340         else if (conn->cmd == SDB_CONNECTION_IDLE)
 341                 errmsg = "Invalid command 0";
 342
 343         if (errmsg) {
 344                 size_t len = sdb_strbuf_len(conn->buf);
 345
 346                 sdb_strbuf_sprintf(conn->errbuf, "%s", errmsg);
 347                 sdb_connection_send(conn, SDB_CONNECTION_ERROR,
 348                                 (uint32_t)strlen(errmsg), errmsg);
 349                 conn->skip_len += conn->cmd_len;
 350                 conn->cmd = SDB_CONNECTION_IDLE;
 351                 conn->cmd_len = 0;
 352
 353                 if (len > conn->skip_len)
 354                         len = conn->skip_len;
 355                 sdb_strbuf_skip(conn->buf, 0, len);
 356                 conn->skip_len -= len;
 357                 /* connection_read will handle anything else */
 358         }
 359         return 0;
 360 } /* command_init */
 361
 362 /* returns negative value on error, 0 on EOF, number of octets else */
 363 static ssize_t
 364 connection_read(sdb_conn_t *conn)
 365 {
 366         ssize_t n = 0;
 367
 368         if ((! conn) || (conn->fd < 0))
 369                 return -1;
 370
 371         while (42) {
 372                 ssize_t status;
 373
 374                 errno = 0;
 375                 status = conn->read(conn, 1024);
 376                 if (status < 0) {
 377                         if ((errno == EAGAIN) || (errno == EWOULDBLOCK))
 378                                 break;
 379
 380                         sdb_connection_close(conn);
 381                         return (int)status;
 382                 }
 383                 else if (! status) /* EOF */
 384                         break;
 385
 386                 if (conn->skip_len) {
 387                         size_t len = (size_t)status < conn->skip_len
 388                                 ? (size_t)status : conn->skip_len;
 389                         sdb_strbuf_skip(conn->buf, 0, len);
 390                         conn->skip_len -= len;
 391                 }
 392
 393                 n += status;
 394
 395                 /* give the main loop a chance to execute commands (and free up buffer
 396                  * space) on large amounts of incoming traffic */
 397                 if (n > 1024 * 1024)
 398                         break;
 399         }
 400
 401         return n;
 402 } /* connection_read */
 403
 404 /*
 405  * public API
 406  */
 407
 408 int
 409 sdb_connection_enable_logging(void)
 410 {
 411         return sdb_plugin_register_log("connection-logger", connection_log,
 412                         /* user_data = */ NULL);
 413 } /* sdb_connection_enable_logging */
 414
 415 sdb_conn_t *
 416 sdb_connection_accept(int fd, sdb_conn_setup_cb setup, void *user_data)
 417 {
 418         sdb_conn_t *conn;
 419         const char *peer = "unknown";
 420
 421         if (fd < 0)
 422                 return NULL;
 423
 424         /* the placeholder will be replaced with the accepted file
 425          * descriptor when initializing the object */
 426         conn = CONN(sdb_object_create(CONN_FD_PREFIX CONN_FD_PLACEHOLDER,
 427                                 connection_type, fd));
 428         if (setup && (setup(conn, user_data) < 0)) {
 429                 sdb_object_deref(SDB_OBJ(conn));
 430                 return NULL;
 431         }
 432
 433         if (conn->username)
 434                 peer = conn->username;
 435
 436         if (conn->client_addr.ss_family == AF_UNIX) {
 437                 sdb_log(SDB_LOG_INFO,
 438                                 "frontend: Accepted connection from peer %s", peer);
 439         }
 440         else {
 441                 char host[1024] = "<unknown>", port[32] = "";
 442                 getnameinfo((struct sockaddr *)&conn->client_addr,
 443                                 conn->client_addr_len, host, sizeof(host), port, sizeof(port),
 444                                 NI_NUMERICHOST | NI_NUMERICSERV);
 445                 sdb_log(SDB_LOG_INFO, "frontend: Accepted connection from "
 446                                 "peer %s at %s:%s", peer, host, port);
 447         }
 448         return conn;
 449 } /* sdb_connection_create */
 450
 451 void
 452 sdb_connection_close(sdb_conn_t *conn)
 453 {
 454         if (! conn)
 455                 return;
 456
 457         if (conn->finish)
 458                 conn->finish(conn);
 459         conn->finish = NULL;
 460
 461         /* close the connection even if someone else still references it */
 462         if (conn->fd >= 0)
 463                 close(conn->fd);
 464         conn->fd = -1;
 465 } /* sdb_connection_close */
 466
 467 ssize_t
 468 sdb_connection_handle(sdb_conn_t *conn)
 469 {
 470         ssize_t n = 0;
 471
 472         sdb_conn_set_ctx(conn);
 473
 474         while (42) {
 475                 ssize_t status = connection_read(conn);
 476
 477                 if ((conn->cmd == SDB_CONNECTION_IDLE) && (! conn->cmd_len)
 478                                 && (sdb_strbuf_len(conn->buf) >= 2 * sizeof(int32_t)))
 479                         command_init(conn);
 480                 if ((conn->cmd != SDB_CONNECTION_IDLE)
 481                                 && (sdb_strbuf_len(conn->buf) >= conn->cmd_len)) {
 482                         command_handle(conn);
 483
 484                         /* remove the command from the buffer */
 485                         if (conn->cmd_len)
 486                                 sdb_strbuf_skip(conn->buf, 0, conn->cmd_len);
 487                         conn->cmd = SDB_CONNECTION_IDLE;
 488                         conn->cmd_len = 0;
 489                 }
 490
 491                 if (status <= 0)
 492                         break;
 493
 494                 n += status;
 495         }
 496
 497         sdb_conn_set_ctx(NULL);
 498         return n;
 499 } /* sdb_connection_handle */
 500
 501 ssize_t
 502 sdb_connection_send(sdb_conn_t *conn, uint32_t code,
 503                 uint32_t msg_len, const char *msg)
 504 {
 505         char buf[2 * sizeof(uint32_t) + msg_len];
 506         ssize_t status;
 507
 508         if ((! conn) || (conn->fd < 0))
 509                 return -1;
 510         if (sdb_proto_marshal(buf, sizeof(buf), code, msg_len, msg) < 0)
 511                 return -1;
 512
 513         status = conn->write(conn, buf, sizeof(buf));
 514         if (status < 0) {
 515                 char errbuf[1024];
 516
 517                 /* tell other code that there was a problem and, more importantly,
 518                  * make sure we don't try to send further logs to the connection */
 519                 sdb_connection_close(conn);
 520                 conn->ready = 0;
 521
 522                 sdb_log(SDB_LOG_ERR, "frontend: Failed to send msg "
 523                                 "(code: %u, len: %u) to client: %s", code, msg_len,
 524                                 sdb_strerror(errno, errbuf, sizeof(errbuf)));
 525         }
 526         return status;
 527 } /* sdb_connection_send */
 528
 529 int
 530 sdb_connection_ping(sdb_conn_t *conn)
 531 {
 532         if ((! conn) || (conn->cmd != SDB_CONNECTION_PING))
 533                 return -1;
 534
 535         /* we're alive */
 536         sdb_connection_send(conn, SDB_CONNECTION_OK, 0, NULL);
 537         return 0;
 538 } /* sdb_connection_ping */
 539
 540 int
 541 sdb_connection_server_version(sdb_conn_t *conn)
 542 {
 543         char msg[sizeof(uint32_t) + strlen(SDB_VERSION_EXTRA) + 1];
 544
 545         if ((! conn) || (conn->cmd != SDB_CONNECTION_SERVER_VERSION))
 546                 return -1;
 547
 548         sdb_proto_marshal_int32(msg, sizeof(msg), (uint32_t)SDB_VERSION);
 549         strncpy(msg + sizeof(uint32_t), SDB_VERSION_EXTRA,
 550                         sizeof(msg) - sizeof(uint32_t));
 551         sdb_connection_send(conn, SDB_CONNECTION_OK, (uint32_t)sizeof(msg), msg);
 552         return 0;
 553 } /* sdb_connection_server_version */
 554
 555 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */
 556