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         if (conn->client_addr.ss_family == AF_UNIX) {
 174                 sdb_log(SDB_LOG_DEBUG, "frontend: Closing connection %s from peer %s",
 175                                 obj->name, conn->username);
 176         }
 177         else {
 178                 char host[1024] = "<unknown>", port[32] = "";
 179                 getnameinfo((struct sockaddr *)&conn->client_addr,
 180                                 conn->client_addr_len, host, sizeof(host), port, sizeof(port),
 181                                 NI_NUMERICHOST | NI_NUMERICSERV);
 182                 sdb_log(SDB_LOG_DEBUG, "frontend: Closing connection %s from peer %s "
 183                                 "at %s:%s", obj->name, conn->username, host, port);
 184         }
 185         sdb_connection_close(conn);
 186
 187         if (conn->username)
 188                 free(conn->username);
 189         conn->username = NULL;
 190
 191         sdb_strbuf_destroy(conn->buf);
 192         conn->buf = NULL;
 193         sdb_strbuf_destroy(conn->errbuf);
 194         conn->errbuf = NULL;
 195 } /* connection_destroy */
 196
 197 static sdb_type_t connection_type = {
 198         /* size = */ sizeof(sdb_conn_t),
 199         /* init = */ connection_init,
 200         /* destroy = */ connection_destroy,
 201 };
 202
 203 /*
 204  * private helper functions
 205  */
 206
 207 static void
 208 sdb_conn_ctx_destructor(void *c)
 209 {
 210         sdb_object_t *conn = c;
 211
 212         if (! conn)
 213                 return;
 214         sdb_object_deref(conn);
 215 } /* sdb_conn_ctx_destructor */
 216
 217 static void
 218 sdb_conn_ctx_init(void)
 219 {
 220         if (conn_ctx_key_initialized)
 221                 return;
 222
 223         pthread_key_create(&conn_ctx_key, sdb_conn_ctx_destructor);
 224         conn_ctx_key_initialized = 1;
 225 } /* sdb_conn_ctx_init */
 226
 227 static void
 228 sdb_conn_set_ctx(sdb_conn_t *conn)
 229 {
 230         sdb_conn_t *old;
 231
 232         sdb_conn_ctx_init();
 233
 234         old = pthread_getspecific(conn_ctx_key);
 235         if (old)
 236                 sdb_object_deref(SDB_OBJ(old));
 237         if (conn)
 238                 sdb_object_ref(SDB_OBJ(conn));
 239         pthread_setspecific(conn_ctx_key, conn);
 240 } /* sdb_conn_set_ctx */
 241
 242 static sdb_conn_t *
 243 sdb_conn_get_ctx(void)
 244 {
 245         if (! conn_ctx_key_initialized)
 246                 return NULL;
 247         return pthread_getspecific(conn_ctx_key);
 248 } /* sdb_conn_get_ctx */
 249
 250 /*
 251  * connection handler functions
 252  */
 253
 254 /*
 255  * connection_log:
 256  * Send a log message originating from the current thread to the client.
 257  */
 258 static int
 259 connection_log(int prio, const char *msg,
 260                 sdb_object_t __attribute__((unused)) *user_data)
 261 {
 262         uint32_t len = (uint32_t)sizeof(uint32_t) + (uint32_t)strlen(msg);
 263         uint32_t p = htonl((uint32_t)prio);
 264         char tmp[len + 1];
 265
 266         sdb_conn_t *conn;
 267
 268         conn = sdb_conn_get_ctx();
 269         /* no connection associated to this thread
 270          * or startup not done yet => don't leak any information */
 271         if ((! conn) || (! conn->ready))
 272                 return 0;
 273
 274         /* XXX: make the log-level configurable by the client at runtime */
 275         if (prio >= SDB_LOG_DEBUG)
 276                 return 0;
 277
 278         memcpy(tmp, &p, sizeof(p));
 279         strcpy(tmp + sizeof(p), msg);
 280
 281         if (sdb_connection_send(conn, SDB_CONNECTION_LOG, len, tmp) < 0)
 282                 return -1;
 283         return 0;
 284 } /* connection_log */
 285
 286 static int
 287 command_handle(sdb_conn_t *conn)
 288 {
 289         int status = -1;
 290
 291         assert(conn && (conn->cmd != SDB_CONNECTION_IDLE));
 292         assert(! conn->skip_len);
 293
 294         if (conn->cmd == SDB_CONNECTION_PING)
 295                 status = sdb_connection_ping(conn);
 296         else if (conn->cmd == SDB_CONNECTION_STARTUP)
 297                 status = sdb_conn_session_start(conn);
 298
 299         else if (conn->cmd == SDB_CONNECTION_QUERY)
 300                 status = sdb_conn_query(conn);
 301         else if (conn->cmd == SDB_CONNECTION_FETCH)
 302                 status = sdb_conn_fetch(conn);
 303         else if (conn->cmd == SDB_CONNECTION_LIST)
 304                 status = sdb_conn_list(conn);
 305         else if (conn->cmd == SDB_CONNECTION_LOOKUP)
 306                 status = sdb_conn_lookup(conn);
 307         else if (conn->cmd == SDB_CONNECTION_STORE)
 308                 status = sdb_conn_store(conn);
 309
 310         else if (conn->cmd == SDB_CONNECTION_SERVER_VERSION)
 311                 status = sdb_connection_server_version(conn);
 312
 313         else {
 314                 sdb_log(SDB_LOG_WARNING, "frontend: Ignoring invalid command %#x",
 315                                 conn->cmd);
 316                 sdb_strbuf_sprintf(conn->errbuf, "Invalid command %#x", conn->cmd);
 317                 status = -1;
 318         }
 319
 320         if (status) {
 321                 if (! sdb_strbuf_len(conn->errbuf))
 322                         sdb_strbuf_sprintf(conn->errbuf, "Failed to execute command");
 323                 sdb_connection_send(conn, SDB_CONNECTION_ERROR,
 324                                 (uint32_t)sdb_strbuf_len(conn->errbuf),
 325                                 sdb_strbuf_string(conn->errbuf));
 326         }
 327         return status;
 328 } /* command_handle */
 329
 330 /* initialize the connection state information */
 331 static int
 332 command_init(sdb_conn_t *conn)
 333 {
 334         const char *errmsg = NULL;
 335
 336         assert(conn && (conn->cmd == SDB_CONNECTION_IDLE) && (! conn->cmd_len));
 337
 338         if (conn->skip_len)
 339                 return -1;
 340
 341         /* reset */
 342         sdb_strbuf_clear(conn->errbuf);
 343
 344         if (sdb_proto_unmarshal_header(SDB_STRBUF_STR(conn->buf),
 345                                 &conn->cmd, &conn->cmd_len) < 0)
 346                 return -1;
 347         sdb_strbuf_skip(conn->buf, 0, 2 * sizeof(uint32_t));
 348
 349         if ((! conn->ready) && (conn->cmd != SDB_CONNECTION_STARTUP))
 350                 errmsg = "Authentication required";
 351         else if (conn->cmd == SDB_CONNECTION_IDLE)
 352                 errmsg = "Invalid command 0";
 353
 354         if (errmsg) {
 355                 size_t len = sdb_strbuf_len(conn->buf);
 356
 357                 sdb_strbuf_sprintf(conn->errbuf, "%s", errmsg);
 358                 sdb_connection_send(conn, SDB_CONNECTION_ERROR,
 359                                 (uint32_t)strlen(errmsg), errmsg);
 360                 conn->skip_len += conn->cmd_len;
 361                 conn->cmd = SDB_CONNECTION_IDLE;
 362                 conn->cmd_len = 0;
 363
 364                 if (len > conn->skip_len)
 365                         len = conn->skip_len;
 366                 sdb_strbuf_skip(conn->buf, 0, len);
 367                 conn->skip_len -= len;
 368                 /* connection_read will handle anything else */
 369         }
 370         return 0;
 371 } /* command_init */
 372
 373 /* returns negative value on error, 0 on EOF, number of octets else */
 374 static ssize_t
 375 connection_read(sdb_conn_t *conn)
 376 {
 377         ssize_t n = 0;
 378
 379         if ((! conn) || (conn->fd < 0))
 380                 return -1;
 381
 382         while (42) {
 383                 ssize_t status;
 384
 385                 errno = 0;
 386                 status = conn->read(conn, 1024);
 387                 if (status < 0) {
 388                         if ((errno == EAGAIN) || (errno == EWOULDBLOCK))
 389                                 break;
 390
 391                         sdb_connection_close(conn);
 392                         return (int)status;
 393                 }
 394                 else if (! status) /* EOF */
 395                         break;
 396
 397                 if (conn->skip_len) {
 398                         size_t len = (size_t)status < conn->skip_len
 399                                 ? (size_t)status : conn->skip_len;
 400                         sdb_strbuf_skip(conn->buf, 0, len);
 401                         conn->skip_len -= len;
 402                 }
 403
 404                 n += status;
 405
 406                 /* give the main loop a chance to execute commands (and free up buffer
 407                  * space) on large amounts of incoming traffic */
 408                 if (n > 1024 * 1024)
 409                         break;
 410         }
 411
 412         return n;
 413 } /* connection_read */
 414
 415 /*
 416  * public API
 417  */
 418
 419 int
 420 sdb_connection_enable_logging(void)
 421 {
 422         return sdb_plugin_register_log("connection-logger", connection_log,
 423                         /* user_data = */ NULL);
 424 } /* sdb_connection_enable_logging */
 425
 426 sdb_conn_t *
 427 sdb_connection_accept(int fd, sdb_conn_setup_cb setup, void *user_data)
 428 {
 429         sdb_conn_t *conn;
 430         const char *peer = "unknown";
 431
 432         if (fd < 0)
 433                 return NULL;
 434
 435         /* the placeholder will be replaced with the accepted file
 436          * descriptor when initializing the object */
 437         conn = CONN(sdb_object_create(CONN_FD_PREFIX CONN_FD_PLACEHOLDER,
 438                                 connection_type, fd));
 439         if (setup && (setup(conn, user_data) < 0)) {
 440                 sdb_object_deref(SDB_OBJ(conn));
 441                 return NULL;
 442         }
 443
 444         if (conn->username)
 445                 peer = conn->username;
 446
 447         if (conn->client_addr.ss_family == AF_UNIX) {
 448                 sdb_log(SDB_LOG_INFO,
 449                                 "frontend: Accepted connection from peer %s", peer);
 450         }
 451         else {
 452                 char host[1024] = "<unknown>", port[32] = "";
 453                 getnameinfo((struct sockaddr *)&conn->client_addr,
 454                                 conn->client_addr_len, host, sizeof(host), port, sizeof(port),
 455                                 NI_NUMERICHOST | NI_NUMERICSERV);
 456                 sdb_log(SDB_LOG_INFO, "frontend: Accepted connection from "
 457                                 "peer %s at %s:%s", peer, host, port);
 458         }
 459         return conn;
 460 } /* sdb_connection_create */
 461
 462 void
 463 sdb_connection_close(sdb_conn_t *conn)
 464 {
 465         if (! conn)
 466                 return;
 467
 468         if (conn->finish)
 469                 conn->finish(conn);
 470         conn->finish = NULL;
 471
 472         /* close the connection even if someone else still references it */
 473         if (conn->fd >= 0)
 474                 close(conn->fd);
 475         conn->fd = -1;
 476 } /* sdb_connection_close */
 477
 478 ssize_t
 479 sdb_connection_handle(sdb_conn_t *conn)
 480 {
 481         ssize_t n = 0;
 482
 483         sdb_conn_set_ctx(conn);
 484
 485         while (42) {
 486                 ssize_t status = connection_read(conn);
 487
 488                 if ((conn->cmd == SDB_CONNECTION_IDLE) && (! conn->cmd_len)
 489                                 && (sdb_strbuf_len(conn->buf) >= 2 * sizeof(int32_t)))
 490                         command_init(conn);
 491                 if ((conn->cmd != SDB_CONNECTION_IDLE)
 492                                 && (sdb_strbuf_len(conn->buf) >= conn->cmd_len)) {
 493                         command_handle(conn);
 494
 495                         /* remove the command from the buffer */
 496                         if (conn->cmd_len)
 497                                 sdb_strbuf_skip(conn->buf, 0, conn->cmd_len);
 498                         conn->cmd = SDB_CONNECTION_IDLE;
 499                         conn->cmd_len = 0;
 500                 }
 501
 502                 if (status <= 0)
 503                         break;
 504
 505                 n += status;
 506         }
 507
 508         sdb_conn_set_ctx(NULL);
 509         return n;
 510 } /* sdb_connection_handle */
 511
 512 ssize_t
 513 sdb_connection_send(sdb_conn_t *conn, uint32_t code,
 514                 uint32_t msg_len, const char *msg)
 515 {
 516         char buf[2 * sizeof(uint32_t) + msg_len];
 517         ssize_t status;
 518
 519         if ((! conn) || (conn->fd < 0))
 520                 return -1;
 521         if (sdb_proto_marshal(buf, sizeof(buf), code, msg_len, msg) < 0)
 522                 return -1;
 523
 524         status = conn->write(conn, buf, sizeof(buf));
 525         if (status < 0) {
 526                 char errbuf[1024];
 527
 528                 /* tell other code that there was a problem and, more importantly,
 529                  * make sure we don't try to send further logs to the connection */
 530                 sdb_connection_close(conn);
 531                 conn->ready = 0;
 532
 533                 sdb_log(SDB_LOG_ERR, "frontend: Failed to send msg "
 534                                 "(code: %u, len: %u) to client: %s", code, msg_len,
 535                                 sdb_strerror(errno, errbuf, sizeof(errbuf)));
 536         }
 537         return status;
 538 } /* sdb_connection_send */
 539
 540 int
 541 sdb_connection_ping(sdb_conn_t *conn)
 542 {
 543         if ((! conn) || (conn->cmd != SDB_CONNECTION_PING))
 544                 return -1;
 545
 546         /* we're alive */
 547         sdb_connection_send(conn, SDB_CONNECTION_OK, 0, NULL);
 548         return 0;
 549 } /* sdb_connection_ping */
 550
 551 int
 552 sdb_connection_server_version(sdb_conn_t *conn)
 553 {
 554         char msg[sizeof(uint32_t) + strlen(SDB_VERSION_EXTRA) + 1];
 555
 556         if ((! conn) || (conn->cmd != SDB_CONNECTION_SERVER_VERSION))
 557                 return -1;
 558
 559         sdb_proto_marshal_int32(msg, sizeof(msg), (uint32_t)SDB_VERSION);
 560         strncpy(msg + sizeof(uint32_t), SDB_VERSION_EXTRA,
 561                         sizeof(msg) - sizeof(uint32_t));
 562         sdb_connection_send(conn, SDB_CONNECTION_OK, (uint32_t)sizeof(msg), msg);
 563         return 0;
 564 } /* sdb_connection_server_version */
 565
 566 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */
 567