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 <stdlib.h>
  48 #include <string.h>
  49
  50 #include <pthread.h>
  51
  52 /*
  53  * private variables
  54  */
  55
  56 static pthread_key_t conn_ctx_key;
  57 static bool          conn_ctx_key_initialized = 0;
  58
  59 /*
  60  * private types
  61  */
  62
  63 /* name of connection objects */
  64 #define CONN_FD_PREFIX "conn#"
  65 #define CONN_FD_PLACEHOLDER "XXXXXXX"
  66
  67 static ssize_t
  68 conn_read(sdb_conn_t *conn, size_t len)
  69 {
  70         return sdb_strbuf_read(conn->buf, conn->fd, len);
  71 } /* conn_read */
  72
  73 static ssize_t
  74 conn_write(sdb_conn_t *conn, const void *buf, size_t len)
  75 {
  76         return sdb_write(conn->fd, len, buf);
  77 } /* conn_write */
  78
  79 static int
  80 connection_init(sdb_object_t *obj, va_list ap)
  81 {
  82         sdb_conn_t *conn;
  83         int sock_fd;
  84         int sock_fl;
  85
  86         assert(obj);
  87         conn = CONN(obj);
  88
  89         sock_fd = va_arg(ap, int);
  90
  91         conn->buf = sdb_strbuf_create(/* size = */ 128);
  92         if (! conn->buf) {
  93                 sdb_log(SDB_LOG_ERR, "frontend: Failed to allocate a read buffer "
  94                                 "for a new connection");
  95                 return -1;
  96         }
  97         conn->errbuf = sdb_strbuf_create(0);
  98         if (! conn->errbuf) {
  99                 sdb_log(SDB_LOG_ERR, "frontend: Failed to allocate an error buffer "
 100                                 "for a new connection");
 101                 return -1;
 102         }
 103
 104         conn->client_addr_len = sizeof(conn->client_addr);
 105         conn->fd = accept(sock_fd, (struct sockaddr *)&conn->client_addr,
 106                         &conn->client_addr_len);
 107
 108         if (conn->fd < 0) {
 109                 char buf[1024];
 110                 sdb_log(SDB_LOG_ERR, "frontend: Failed to accept remote "
 111                                 "connection: %s", sdb_strerror(errno,
 112                                         buf, sizeof(buf)));
 113                 return -1;
 114         }
 115
 116         /* update the object name */
 117         snprintf(obj->name + strlen(CONN_FD_PREFIX),
 118                         strlen(CONN_FD_PLACEHOLDER), "%i", conn->fd);
 119
 120         /* defaults */
 121         conn->read = conn_read;
 122         conn->write = conn_write;
 123         conn->finish = NULL;
 124         conn->session = NULL;
 125
 126         if (conn->client_addr.ss_family != AF_UNIX) {
 127                 sdb_log(SDB_LOG_ERR, "frontend: Accepted connection using "
 128                                 "unexpected family type %d", conn->client_addr.ss_family);
 129                 return -1;
 130         }
 131
 132         sock_fl = fcntl(conn->fd, F_GETFL);
 133         if (fcntl(conn->fd, F_SETFL, sock_fl | O_NONBLOCK)) {
 134                 char buf[1024];
 135                 sdb_log(SDB_LOG_ERR, "frontend: Failed to switch connection conn#%i "
 136                                 "to non-blocking mode: %s", conn->fd,
 137                                 sdb_strerror(errno, buf, sizeof(buf)));
 138                 return -1;
 139         }
 140
 141         conn->username = NULL;
 142         conn->ready = 0;
 143
 144         sdb_log(SDB_LOG_DEBUG, "frontend: Accepted connection on fd=%i",
 145                         conn->fd);
 146
 147         conn->cmd = SDB_CONNECTION_IDLE;
 148         conn->cmd_len = 0;
 149         conn->skip_len = 0;
 150         return 0;
 151 } /* connection_init */
 152
 153 static void
 154 connection_destroy(sdb_object_t *obj)
 155 {
 156         sdb_conn_t *conn;
 157         size_t len;
 158
 159         assert(obj);
 160         conn = CONN(obj);
 161
 162         conn->ready = 0;
 163
 164         if (conn->finish)
 165                 conn->finish(conn);
 166         conn->finish = NULL;
 167
 168         if (conn->buf) {
 169                 len = sdb_strbuf_len(conn->buf);
 170                 if (len)
 171                         sdb_log(SDB_LOG_INFO, "frontend: Discarding incomplete command "
 172                                         "(%zu byte%s left in buffer)", len, len == 1 ? "" : "s");
 173         }
 174
 175         sdb_log(SDB_LOG_DEBUG, "frontend: Closing connection %s", obj->name);
 176         sdb_connection_close(conn);
 177
 178         if (conn->username)
 179                 free(conn->username);
 180         conn->username = NULL;
 181
 182         sdb_strbuf_destroy(conn->buf);
 183         conn->buf = NULL;
 184         sdb_strbuf_destroy(conn->errbuf);
 185         conn->errbuf = NULL;
 186 } /* connection_destroy */
 187
 188 static sdb_type_t connection_type = {
 189         /* size = */ sizeof(sdb_conn_t),
 190         /* init = */ connection_init,
 191         /* destroy = */ connection_destroy,
 192 };
 193
 194 /*
 195  * private helper functions
 196  */
 197
 198 static void
 199 sdb_conn_ctx_destructor(void *c)
 200 {
 201         sdb_object_t *conn = c;
 202
 203         if (! conn)
 204                 return;
 205         sdb_object_deref(conn);
 206 } /* sdb_conn_ctx_destructor */
 207
 208 static void
 209 sdb_conn_ctx_init(void)
 210 {
 211         if (conn_ctx_key_initialized)
 212                 return;
 213
 214         pthread_key_create(&conn_ctx_key, sdb_conn_ctx_destructor);
 215         conn_ctx_key_initialized = 1;
 216 } /* sdb_conn_ctx_init */
 217
 218 static void
 219 sdb_conn_set_ctx(sdb_conn_t *conn)
 220 {
 221         sdb_conn_t *old;
 222
 223         sdb_conn_ctx_init();
 224
 225         old = pthread_getspecific(conn_ctx_key);
 226         if (old)
 227                 sdb_object_deref(SDB_OBJ(old));
 228         if (conn)
 229                 sdb_object_ref(SDB_OBJ(conn));
 230         pthread_setspecific(conn_ctx_key, conn);
 231 } /* sdb_conn_set_ctx */
 232
 233 static sdb_conn_t *
 234 sdb_conn_get_ctx(void)
 235 {
 236         if (! conn_ctx_key_initialized)
 237                 return NULL;
 238         return pthread_getspecific(conn_ctx_key);
 239 } /* sdb_conn_get_ctx */
 240
 241 /*
 242  * connection handler functions
 243  */
 244
 245 /*
 246  * connection_log:
 247  * Send a log message originating from the current thread to the client.
 248  */
 249 static int
 250 connection_log(int prio, const char *msg,
 251                 sdb_object_t __attribute__((unused)) *user_data)
 252 {
 253         uint32_t len = (uint32_t)sizeof(uint32_t) + (uint32_t)strlen(msg);
 254         uint32_t p = htonl((uint32_t)prio);
 255         char tmp[len + 1];
 256
 257         sdb_conn_t *conn;
 258
 259         conn = sdb_conn_get_ctx();
 260         /* no connection associated to this thread
 261          * or startup not done yet => don't leak any information */
 262         if ((! conn) || (! conn->ready))
 263                 return 0;
 264
 265         /* XXX: make the log-level configurable by the client at runtime */
 266         if (prio >= SDB_LOG_DEBUG)
 267                 return 0;
 268
 269         memcpy(tmp, &p, sizeof(p));
 270         strcpy(tmp + sizeof(p), msg);
 271
 272         if (sdb_connection_send(conn, SDB_CONNECTION_LOG, len, tmp) < 0)
 273                 return -1;
 274         return 0;
 275 } /* connection_log */
 276
 277 static int
 278 command_handle(sdb_conn_t *conn)
 279 {
 280         int status = -1;
 281
 282         assert(conn && (conn->cmd != SDB_CONNECTION_IDLE));
 283         assert(! conn->skip_len);
 284
 285         sdb_log(SDB_LOG_DEBUG, "frontend: Handling command %u (len: %u)",
 286                         conn->cmd, conn->cmd_len);
 287
 288         if (conn->cmd == SDB_CONNECTION_PING)
 289                 status = sdb_connection_ping(conn);
 290         else if (conn->cmd == SDB_CONNECTION_STARTUP)
 291                 status = sdb_fe_session_start(conn);
 292         else if (conn->cmd == SDB_CONNECTION_QUERY)
 293                 status = sdb_fe_query(conn);
 294         else if (conn->cmd == SDB_CONNECTION_FETCH)
 295                 status = sdb_fe_fetch(conn);
 296         else if (conn->cmd == SDB_CONNECTION_LIST)
 297                 status = sdb_fe_list(conn);
 298         else if (conn->cmd == SDB_CONNECTION_LOOKUP)
 299                 status = sdb_fe_lookup(conn);
 300         else if (conn->cmd == SDB_CONNECTION_STORE)
 301                 status = sdb_fe_store(conn);
 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)
 417 {
 418         if (fd < 0)
 419                 return NULL;
 420
 421         /* the placeholder will be replaced with the accepted file
 422          * descriptor when initializing the object */
 423         return CONN(sdb_object_create(CONN_FD_PREFIX CONN_FD_PLACEHOLDER,
 424                                 connection_type, fd));
 425 } /* sdb_connection_create */
 426
 427 void
 428 sdb_connection_close(sdb_conn_t *conn)
 429 {
 430         if (! conn)
 431                 return;
 432
 433         if (conn->finish)
 434                 conn->finish(conn);
 435         conn->finish = NULL;
 436
 437         /* close the connection even if someone else still references it */
 438         if (conn->fd >= 0)
 439                 close(conn->fd);
 440         conn->fd = -1;
 441 } /* sdb_connection_close */
 442
 443 ssize_t
 444 sdb_connection_handle(sdb_conn_t *conn)
 445 {
 446         ssize_t n = 0;
 447
 448         sdb_conn_set_ctx(conn);
 449
 450         while (42) {
 451                 ssize_t status = connection_read(conn);
 452
 453                 if ((conn->cmd == SDB_CONNECTION_IDLE) && (! conn->cmd_len)
 454                                 && (sdb_strbuf_len(conn->buf) >= 2 * sizeof(int32_t)))
 455                         command_init(conn);
 456                 if ((conn->cmd != SDB_CONNECTION_IDLE)
 457                                 && (sdb_strbuf_len(conn->buf) >= conn->cmd_len)) {
 458                         command_handle(conn);
 459
 460                         /* remove the command from the buffer */
 461                         if (conn->cmd_len)
 462                                 sdb_strbuf_skip(conn->buf, 0, conn->cmd_len);
 463                         conn->cmd = SDB_CONNECTION_IDLE;
 464                         conn->cmd_len = 0;
 465                 }
 466
 467                 if (status <= 0)
 468                         break;
 469
 470                 n += status;
 471         }
 472
 473         sdb_conn_set_ctx(NULL);
 474         return n;
 475 } /* sdb_connection_handle */
 476
 477 ssize_t
 478 sdb_connection_send(sdb_conn_t *conn, uint32_t code,
 479                 uint32_t msg_len, const char *msg)
 480 {
 481         char buf[2 * sizeof(uint32_t) + msg_len];
 482         ssize_t status;
 483
 484         if ((! conn) || (conn->fd < 0))
 485                 return -1;
 486         if (sdb_proto_marshal(buf, sizeof(buf), code, msg_len, msg) < 0)
 487                 return -1;
 488
 489         status = conn->write(conn, buf, sizeof(buf));
 490         if (status < 0) {
 491                 char errbuf[1024];
 492
 493                 /* tell other code that there was a problem and, more importantly,
 494                  * make sure we don't try to send further logs to the connection */
 495                 sdb_connection_close(conn);
 496                 conn->ready = 0;
 497
 498                 sdb_log(SDB_LOG_ERR, "frontend: Failed to send msg "
 499                                 "(code: %u, len: %u) to client: %s", code, msg_len,
 500                                 sdb_strerror(errno, errbuf, sizeof(errbuf)));
 501         }
 502         return status;
 503 } /* sdb_connection_send */
 504
 505 int
 506 sdb_connection_ping(sdb_conn_t *conn)
 507 {
 508         if ((! conn) || (conn->cmd != SDB_CONNECTION_PING))
 509                 return -1;
 510
 511         /* we're alive */
 512         sdb_connection_send(conn, SDB_CONNECTION_OK, 0, NULL);
 513         return 0;
 514 } /* sdb_connection_ping */
 515
 516 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */
 517