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->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         else if (conn->cmd == SDB_CONNECTION_QUERY)
 288                 status = sdb_fe_query(conn);
 289         else if (conn->cmd == SDB_CONNECTION_FETCH)
 290                 status = sdb_fe_fetch(conn);
 291         else if (conn->cmd == SDB_CONNECTION_LIST)
 292                 status = sdb_fe_list(conn);
 293         else if (conn->cmd == SDB_CONNECTION_LOOKUP)
 294                 status = sdb_fe_lookup(conn);
 295         else if (conn->cmd == SDB_CONNECTION_STORE)
 296                 status = sdb_fe_store(conn);
 297         else {
 298                 sdb_log(SDB_LOG_WARNING, "frontend: Ignoring invalid command %#x",
 299                                 conn->cmd);
 300                 sdb_strbuf_sprintf(conn->errbuf, "Invalid command %#x", conn->cmd);
 301                 status = -1;
 302         }
 303
 304         if (status) {
 305                 if (! sdb_strbuf_len(conn->errbuf))
 306                         sdb_strbuf_sprintf(conn->errbuf, "Failed to execute command");
 307                 sdb_connection_send(conn, SDB_CONNECTION_ERROR,
 308                                 (uint32_t)sdb_strbuf_len(conn->errbuf),
 309                                 sdb_strbuf_string(conn->errbuf));
 310         }
 311         return status;
 312 } /* command_handle */
 313
 314 /* initialize the connection state information */
 315 static int
 316 command_init(sdb_conn_t *conn)
 317 {
 318         const char *errmsg = NULL;
 319
 320         assert(conn && (conn->cmd == SDB_CONNECTION_IDLE) && (! conn->cmd_len));
 321
 322         if (conn->skip_len)
 323                 return -1;
 324
 325         /* reset */
 326         sdb_strbuf_clear(conn->errbuf);
 327
 328         if (sdb_proto_unmarshal_header(SDB_STRBUF_STR(conn->buf),
 329                                 &conn->cmd, &conn->cmd_len) < 0)
 330                 return -1;
 331         sdb_strbuf_skip(conn->buf, 0, 2 * sizeof(uint32_t));
 332
 333         if ((! conn->ready) && (conn->cmd != SDB_CONNECTION_STARTUP))
 334                 errmsg = "Authentication required";
 335         else if (conn->cmd == SDB_CONNECTION_IDLE)
 336                 errmsg = "Invalid command 0";
 337
 338         if (errmsg) {
 339                 size_t len = sdb_strbuf_len(conn->buf);
 340
 341                 sdb_strbuf_sprintf(conn->errbuf, "%s", errmsg);
 342                 sdb_connection_send(conn, SDB_CONNECTION_ERROR,
 343                                 (uint32_t)strlen(errmsg), errmsg);
 344                 conn->skip_len += conn->cmd_len;
 345                 conn->cmd = SDB_CONNECTION_IDLE;
 346                 conn->cmd_len = 0;
 347
 348                 if (len > conn->skip_len)
 349                         len = conn->skip_len;
 350                 sdb_strbuf_skip(conn->buf, 0, len);
 351                 conn->skip_len -= len;
 352                 /* connection_read will handle anything else */
 353         }
 354         return 0;
 355 } /* command_init */
 356
 357 /* returns negative value on error, 0 on EOF, number of octets else */
 358 static ssize_t
 359 connection_read(sdb_conn_t *conn)
 360 {
 361         ssize_t n = 0;
 362
 363         if ((! conn) || (conn->fd < 0))
 364                 return -1;
 365
 366         while (42) {
 367                 ssize_t status;
 368
 369                 errno = 0;
 370                 status = conn->read(conn, 1024);
 371                 if (status < 0) {
 372                         if ((errno == EAGAIN) || (errno == EWOULDBLOCK))
 373                                 break;
 374
 375                         sdb_connection_close(conn);
 376                         return (int)status;
 377                 }
 378                 else if (! status) /* EOF */
 379                         break;
 380
 381                 if (conn->skip_len) {
 382                         size_t len = (size_t)status < conn->skip_len
 383                                 ? (size_t)status : conn->skip_len;
 384                         sdb_strbuf_skip(conn->buf, 0, len);
 385                         conn->skip_len -= len;
 386                 }
 387
 388                 n += status;
 389
 390                 /* give the main loop a chance to execute commands (and free up buffer
 391                  * space) on large amounts of incoming traffic */
 392                 if (n > 1024 * 1024)
 393                         break;
 394         }
 395
 396         return n;
 397 } /* connection_read */
 398
 399 /*
 400  * public API
 401  */
 402
 403 int
 404 sdb_connection_enable_logging(void)
 405 {
 406         return sdb_plugin_register_log("connection-logger", connection_log,
 407                         /* user_data = */ NULL);
 408 } /* sdb_connection_enable_logging */
 409
 410 sdb_conn_t *
 411 sdb_connection_accept(int fd, sdb_conn_setup_cb setup, void *user_data)
 412 {
 413         sdb_conn_t *conn;
 414         const char *peer = "unknown";
 415
 416         if (fd < 0)
 417                 return NULL;
 418
 419         /* the placeholder will be replaced with the accepted file
 420          * descriptor when initializing the object */
 421         conn = CONN(sdb_object_create(CONN_FD_PREFIX CONN_FD_PLACEHOLDER,
 422                                 connection_type, fd));
 423         if (setup && (setup(conn, user_data) < 0)) {
 424                 sdb_object_deref(SDB_OBJ(conn));
 425                 return NULL;
 426         }
 427
 428         if (conn->username)
 429                 peer = conn->username;
 430
 431         if (conn->client_addr.ss_family == AF_UNIX) {
 432                 sdb_log(SDB_LOG_INFO,
 433                                 "frontend: Accepted connection from peer %s", peer);
 434         }
 435         else {
 436                 char host[1024] = "<unknown>", port[32] = "";
 437                 getnameinfo((struct sockaddr *)&conn->client_addr,
 438                                 conn->client_addr_len, host, sizeof(host), port, sizeof(port),
 439                                 NI_NUMERICHOST | NI_NUMERICSERV);
 440                 sdb_log(SDB_LOG_INFO, "frontend: Accepted connection from "
 441                                 "peer %s at %s:%s", peer, host, port);
 442         }
 443         return conn;
 444 } /* sdb_connection_create */
 445
 446 void
 447 sdb_connection_close(sdb_conn_t *conn)
 448 {
 449         if (! conn)
 450                 return;
 451
 452         if (conn->finish)
 453                 conn->finish(conn);
 454         conn->finish = NULL;
 455
 456         /* close the connection even if someone else still references it */
 457         if (conn->fd >= 0)
 458                 close(conn->fd);
 459         conn->fd = -1;
 460 } /* sdb_connection_close */
 461
 462 ssize_t
 463 sdb_connection_handle(sdb_conn_t *conn)
 464 {
 465         ssize_t n = 0;
 466
 467         sdb_conn_set_ctx(conn);
 468
 469         while (42) {
 470                 ssize_t status = connection_read(conn);
 471
 472                 if ((conn->cmd == SDB_CONNECTION_IDLE) && (! conn->cmd_len)
 473                                 && (sdb_strbuf_len(conn->buf) >= 2 * sizeof(int32_t)))
 474                         command_init(conn);
 475                 if ((conn->cmd != SDB_CONNECTION_IDLE)
 476                                 && (sdb_strbuf_len(conn->buf) >= conn->cmd_len)) {
 477                         command_handle(conn);
 478
 479                         /* remove the command from the buffer */
 480                         if (conn->cmd_len)
 481                                 sdb_strbuf_skip(conn->buf, 0, conn->cmd_len);
 482                         conn->cmd = SDB_CONNECTION_IDLE;
 483                         conn->cmd_len = 0;
 484                 }
 485
 486                 if (status <= 0)
 487                         break;
 488
 489                 n += status;
 490         }
 491
 492         sdb_conn_set_ctx(NULL);
 493         return n;
 494 } /* sdb_connection_handle */
 495
 496 ssize_t
 497 sdb_connection_send(sdb_conn_t *conn, uint32_t code,
 498                 uint32_t msg_len, const char *msg)
 499 {
 500         char buf[2 * sizeof(uint32_t) + msg_len];
 501         ssize_t status;
 502
 503         if ((! conn) || (conn->fd < 0))
 504                 return -1;
 505         if (sdb_proto_marshal(buf, sizeof(buf), code, msg_len, msg) < 0)
 506                 return -1;
 507
 508         status = conn->write(conn, buf, sizeof(buf));
 509         if (status < 0) {
 510                 char errbuf[1024];
 511
 512                 /* tell other code that there was a problem and, more importantly,
 513                  * make sure we don't try to send further logs to the connection */
 514                 sdb_connection_close(conn);
 515                 conn->ready = 0;
 516
 517                 sdb_log(SDB_LOG_ERR, "frontend: Failed to send msg "
 518                                 "(code: %u, len: %u) to client: %s", code, msg_len,
 519                                 sdb_strerror(errno, errbuf, sizeof(errbuf)));
 520         }
 521         return status;
 522 } /* sdb_connection_send */
 523
 524 int
 525 sdb_connection_ping(sdb_conn_t *conn)
 526 {
 527         if ((! conn) || (conn->cmd != SDB_CONNECTION_PING))
 528                 return -1;
 529
 530         /* we're alive */
 531         sdb_connection_send(conn, SDB_CONNECTION_OK, 0, NULL);
 532         return 0;
 533 } /* sdb_connection_ping */
 534
 535 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */
 536