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         sdb_log(SDB_LOG_DEBUG, "frontend: Handling command %u (len: %u)",
 284                         conn->cmd, conn->cmd_len);
 285
 286         if (conn->cmd == SDB_CONNECTION_PING)
 287                 status = sdb_connection_ping(conn);
 288         else if (conn->cmd == SDB_CONNECTION_STARTUP)
 289                 status = sdb_fe_session_start(conn);
 290         else if (conn->cmd == SDB_CONNECTION_QUERY)
 291                 status = sdb_fe_query(conn);
 292         else if (conn->cmd == SDB_CONNECTION_FETCH)
 293                 status = sdb_fe_fetch(conn);
 294         else if (conn->cmd == SDB_CONNECTION_LIST)
 295                 status = sdb_fe_list(conn);
 296         else if (conn->cmd == SDB_CONNECTION_LOOKUP)
 297                 status = sdb_fe_lookup(conn);
 298         else if (conn->cmd == SDB_CONNECTION_STORE)
 299                 status = sdb_fe_store(conn);
 300         else {
 301                 sdb_log(SDB_LOG_WARNING, "frontend: Ignoring invalid command %#x",
 302                                 conn->cmd);
 303                 sdb_strbuf_sprintf(conn->errbuf, "Invalid command %#x", conn->cmd);
 304                 status = -1;
 305         }
 306
 307         if (status) {
 308                 if (! sdb_strbuf_len(conn->errbuf))
 309                         sdb_strbuf_sprintf(conn->errbuf, "Failed to execute command");
 310                 sdb_connection_send(conn, SDB_CONNECTION_ERROR,
 311                                 (uint32_t)sdb_strbuf_len(conn->errbuf),
 312                                 sdb_strbuf_string(conn->errbuf));
 313         }
 314         return status;
 315 } /* command_handle */
 316
 317 /* initialize the connection state information */
 318 static int
 319 command_init(sdb_conn_t *conn)
 320 {
 321         const char *errmsg = NULL;
 322
 323         assert(conn && (conn->cmd == SDB_CONNECTION_IDLE) && (! conn->cmd_len));
 324
 325         if (conn->skip_len)
 326                 return -1;
 327
 328         /* reset */
 329         sdb_strbuf_clear(conn->errbuf);
 330
 331         if (sdb_proto_unmarshal_header(SDB_STRBUF_STR(conn->buf),
 332                                 &conn->cmd, &conn->cmd_len) < 0)
 333                 return -1;
 334         sdb_strbuf_skip(conn->buf, 0, 2 * sizeof(uint32_t));
 335
 336         if ((! conn->ready) && (conn->cmd != SDB_CONNECTION_STARTUP))
 337                 errmsg = "Authentication required";
 338         else if (conn->cmd == SDB_CONNECTION_IDLE)
 339                 errmsg = "Invalid command 0";
 340
 341         if (errmsg) {
 342                 size_t len = sdb_strbuf_len(conn->buf);
 343
 344                 sdb_strbuf_sprintf(conn->errbuf, "%s", errmsg);
 345                 sdb_connection_send(conn, SDB_CONNECTION_ERROR,
 346                                 (uint32_t)strlen(errmsg), errmsg);
 347                 conn->skip_len += conn->cmd_len;
 348                 conn->cmd = SDB_CONNECTION_IDLE;
 349                 conn->cmd_len = 0;
 350
 351                 if (len > conn->skip_len)
 352                         len = conn->skip_len;
 353                 sdb_strbuf_skip(conn->buf, 0, len);
 354                 conn->skip_len -= len;
 355                 /* connection_read will handle anything else */
 356         }
 357         return 0;
 358 } /* command_init */
 359
 360 /* returns negative value on error, 0 on EOF, number of octets else */
 361 static ssize_t
 362 connection_read(sdb_conn_t *conn)
 363 {
 364         ssize_t n = 0;
 365
 366         if ((! conn) || (conn->fd < 0))
 367                 return -1;
 368
 369         while (42) {
 370                 ssize_t status;
 371
 372                 errno = 0;
 373                 status = conn->read(conn, 1024);
 374                 if (status < 0) {
 375                         if ((errno == EAGAIN) || (errno == EWOULDBLOCK))
 376                                 break;
 377
 378                         sdb_connection_close(conn);
 379                         return (int)status;
 380                 }
 381                 else if (! status) /* EOF */
 382                         break;
 383
 384                 if (conn->skip_len) {
 385                         size_t len = (size_t)status < conn->skip_len
 386                                 ? (size_t)status : conn->skip_len;
 387                         sdb_strbuf_skip(conn->buf, 0, len);
 388                         conn->skip_len -= len;
 389                 }
 390
 391                 n += status;
 392
 393                 /* give the main loop a chance to execute commands (and free up buffer
 394                  * space) on large amounts of incoming traffic */
 395                 if (n > 1024 * 1024)
 396                         break;
 397         }
 398
 399         return n;
 400 } /* connection_read */
 401
 402 /*
 403  * public API
 404  */
 405
 406 int
 407 sdb_connection_enable_logging(void)
 408 {
 409         return sdb_plugin_register_log("connection-logger", connection_log,
 410                         /* user_data = */ NULL);
 411 } /* sdb_connection_enable_logging */
 412
 413 sdb_conn_t *
 414 sdb_connection_accept(int fd, sdb_conn_setup_cb setup, void *user_data)
 415 {
 416         sdb_conn_t *conn;
 417         const char *peer = "unknown";
 418
 419         if (fd < 0)
 420                 return NULL;
 421
 422         /* the placeholder will be replaced with the accepted file
 423          * descriptor when initializing the object */
 424         conn = CONN(sdb_object_create(CONN_FD_PREFIX CONN_FD_PLACEHOLDER,
 425                                 connection_type, fd));
 426         if (setup && (setup(conn, user_data) < 0)) {
 427                 sdb_object_deref(SDB_OBJ(conn));
 428                 return NULL;
 429         }
 430
 431         if (conn->username)
 432                 peer = conn->username;
 433
 434         if (conn->client_addr.ss_family == AF_UNIX) {
 435                 sdb_log(SDB_LOG_INFO,
 436                                 "frontend: Accepted connection from peer %s", peer);
 437         }
 438         else {
 439                 char host[1024] = "<unknown>", port[32] = "";
 440                 getnameinfo((struct sockaddr *)&conn->client_addr,
 441                                 conn->client_addr_len, host, sizeof(host), port, sizeof(port),
 442                                 NI_NUMERICHOST | NI_NUMERICSERV);
 443                 sdb_log(SDB_LOG_INFO, "frontend: Accepted connection from "
 444                                 "peer %s at %s:%s", peer, host, port);
 445         }
 446         return conn;
 447 } /* sdb_connection_create */
 448
 449 void
 450 sdb_connection_close(sdb_conn_t *conn)
 451 {
 452         if (! conn)
 453                 return;
 454
 455         if (conn->finish)
 456                 conn->finish(conn);
 457         conn->finish = NULL;
 458
 459         /* close the connection even if someone else still references it */
 460         if (conn->fd >= 0)
 461                 close(conn->fd);
 462         conn->fd = -1;
 463 } /* sdb_connection_close */
 464
 465 ssize_t
 466 sdb_connection_handle(sdb_conn_t *conn)
 467 {
 468         ssize_t n = 0;
 469
 470         sdb_conn_set_ctx(conn);
 471
 472         while (42) {
 473                 ssize_t status = connection_read(conn);
 474
 475                 if ((conn->cmd == SDB_CONNECTION_IDLE) && (! conn->cmd_len)
 476                                 && (sdb_strbuf_len(conn->buf) >= 2 * sizeof(int32_t)))
 477                         command_init(conn);
 478                 if ((conn->cmd != SDB_CONNECTION_IDLE)
 479                                 && (sdb_strbuf_len(conn->buf) >= conn->cmd_len)) {
 480                         command_handle(conn);
 481
 482                         /* remove the command from the buffer */
 483                         if (conn->cmd_len)
 484                                 sdb_strbuf_skip(conn->buf, 0, conn->cmd_len);
 485                         conn->cmd = SDB_CONNECTION_IDLE;
 486                         conn->cmd_len = 0;
 487                 }
 488
 489                 if (status <= 0)
 490                         break;
 491
 492                 n += status;
 493         }
 494
 495         sdb_conn_set_ctx(NULL);
 496         return n;
 497 } /* sdb_connection_handle */
 498
 499 ssize_t
 500 sdb_connection_send(sdb_conn_t *conn, uint32_t code,
 501                 uint32_t msg_len, const char *msg)
 502 {
 503         char buf[2 * sizeof(uint32_t) + msg_len];
 504         ssize_t status;
 505
 506         if ((! conn) || (conn->fd < 0))
 507                 return -1;
 508         if (sdb_proto_marshal(buf, sizeof(buf), code, msg_len, msg) < 0)
 509                 return -1;
 510
 511         status = conn->write(conn, buf, sizeof(buf));
 512         if (status < 0) {
 513                 char errbuf[1024];
 514
 515                 /* tell other code that there was a problem and, more importantly,
 516                  * make sure we don't try to send further logs to the connection */
 517                 sdb_connection_close(conn);
 518                 conn->ready = 0;
 519
 520                 sdb_log(SDB_LOG_ERR, "frontend: Failed to send msg "
 521                                 "(code: %u, len: %u) to client: %s", code, msg_len,
 522                                 sdb_strerror(errno, errbuf, sizeof(errbuf)));
 523         }
 524         return status;
 525 } /* sdb_connection_send */
 526
 527 int
 528 sdb_connection_ping(sdb_conn_t *conn)
 529 {
 530         if ((! conn) || (conn->cmd != SDB_CONNECTION_PING))
 531                 return -1;
 532
 533         /* we're alive */
 534         sdb_connection_send(conn, SDB_CONNECTION_OK, 0, NULL);
 535         return 0;
 536 } /* sdb_connection_ping */
 537
 538 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */
 539