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         sock_fl = fcntl(conn->fd, F_GETFL);
 127         if (fcntl(conn->fd, F_SETFL, sock_fl | O_NONBLOCK)) {
 128                 char buf[1024];
 129                 sdb_log(SDB_LOG_ERR, "frontend: Failed to switch connection conn#%i "
 130                                 "to non-blocking mode: %s", conn->fd,
 131                                 sdb_strerror(errno, buf, sizeof(buf)));
 132                 return -1;
 133         }
 134
 135         conn->username = NULL;
 136         conn->ready = 0;
 137
 138         sdb_log(SDB_LOG_DEBUG, "frontend: Accepted connection on fd=%i",
 139                         conn->fd);
 140
 141         conn->cmd = SDB_CONNECTION_IDLE;
 142         conn->cmd_len = 0;
 143         conn->skip_len = 0;
 144         return 0;
 145 } /* connection_init */
 146
 147 static void
 148 connection_destroy(sdb_object_t *obj)
 149 {
 150         sdb_conn_t *conn;
 151         size_t len;
 152
 153         assert(obj);
 154         conn = CONN(obj);
 155
 156         conn->ready = 0;
 157
 158         if (conn->finish)
 159                 conn->finish(conn);
 160         conn->finish = NULL;
 161
 162         if (conn->buf) {
 163                 len = sdb_strbuf_len(conn->buf);
 164                 if (len)
 165                         sdb_log(SDB_LOG_INFO, "frontend: Discarding incomplete command "
 166                                         "(%zu byte%s left in buffer)", len, len == 1 ? "" : "s");
 167         }
 168
 169         sdb_log(SDB_LOG_DEBUG, "frontend: Closing connection %s", obj->name);
 170         sdb_connection_close(conn);
 171
 172         if (conn->username)
 173                 free(conn->username);
 174         conn->username = NULL;
 175
 176         sdb_strbuf_destroy(conn->buf);
 177         conn->buf = NULL;
 178         sdb_strbuf_destroy(conn->errbuf);
 179         conn->errbuf = NULL;
 180 } /* connection_destroy */
 181
 182 static sdb_type_t connection_type = {
 183         /* size = */ sizeof(sdb_conn_t),
 184         /* init = */ connection_init,
 185         /* destroy = */ connection_destroy,
 186 };
 187
 188 /*
 189  * private helper functions
 190  */
 191
 192 static void
 193 sdb_conn_ctx_destructor(void *c)
 194 {
 195         sdb_object_t *conn = c;
 196
 197         if (! conn)
 198                 return;
 199         sdb_object_deref(conn);
 200 } /* sdb_conn_ctx_destructor */
 201
 202 static void
 203 sdb_conn_ctx_init(void)
 204 {
 205         if (conn_ctx_key_initialized)
 206                 return;
 207
 208         pthread_key_create(&conn_ctx_key, sdb_conn_ctx_destructor);
 209         conn_ctx_key_initialized = 1;
 210 } /* sdb_conn_ctx_init */
 211
 212 static void
 213 sdb_conn_set_ctx(sdb_conn_t *conn)
 214 {
 215         sdb_conn_t *old;
 216
 217         sdb_conn_ctx_init();
 218
 219         old = pthread_getspecific(conn_ctx_key);
 220         if (old)
 221                 sdb_object_deref(SDB_OBJ(old));
 222         if (conn)
 223                 sdb_object_ref(SDB_OBJ(conn));
 224         pthread_setspecific(conn_ctx_key, conn);
 225 } /* sdb_conn_set_ctx */
 226
 227 static sdb_conn_t *
 228 sdb_conn_get_ctx(void)
 229 {
 230         if (! conn_ctx_key_initialized)
 231                 return NULL;
 232         return pthread_getspecific(conn_ctx_key);
 233 } /* sdb_conn_get_ctx */
 234
 235 /*
 236  * connection handler functions
 237  */
 238
 239 /*
 240  * connection_log:
 241  * Send a log message originating from the current thread to the client.
 242  */
 243 static int
 244 connection_log(int prio, const char *msg,
 245                 sdb_object_t __attribute__((unused)) *user_data)
 246 {
 247         uint32_t len = (uint32_t)sizeof(uint32_t) + (uint32_t)strlen(msg);
 248         uint32_t p = htonl((uint32_t)prio);
 249         char tmp[len + 1];
 250
 251         sdb_conn_t *conn;
 252
 253         conn = sdb_conn_get_ctx();
 254         /* no connection associated to this thread
 255          * or startup not done yet => don't leak any information */
 256         if ((! conn) || (! conn->ready))
 257                 return 0;
 258
 259         /* XXX: make the log-level configurable by the client at runtime */
 260         if (prio >= SDB_LOG_DEBUG)
 261                 return 0;
 262
 263         memcpy(tmp, &p, sizeof(p));
 264         strcpy(tmp + sizeof(p), msg);
 265
 266         if (sdb_connection_send(conn, SDB_CONNECTION_LOG, len, tmp) < 0)
 267                 return -1;
 268         return 0;
 269 } /* connection_log */
 270
 271 static int
 272 command_handle(sdb_conn_t *conn)
 273 {
 274         int status = -1;
 275
 276         assert(conn && (conn->cmd != SDB_CONNECTION_IDLE));
 277         assert(! conn->skip_len);
 278
 279         sdb_log(SDB_LOG_DEBUG, "frontend: Handling command %u (len: %u)",
 280                         conn->cmd, conn->cmd_len);
 281
 282         if (conn->cmd == SDB_CONNECTION_PING)
 283                 status = sdb_connection_ping(conn);
 284         else if (conn->cmd == SDB_CONNECTION_STARTUP)
 285                 status = sdb_fe_session_start(conn);
 286         else if (conn->cmd == SDB_CONNECTION_QUERY)
 287                 status = sdb_fe_query(conn);
 288         else if (conn->cmd == SDB_CONNECTION_FETCH)
 289                 status = sdb_fe_fetch(conn);
 290         else if (conn->cmd == SDB_CONNECTION_LIST)
 291                 status = sdb_fe_list(conn);
 292         else if (conn->cmd == SDB_CONNECTION_LOOKUP)
 293                 status = sdb_fe_lookup(conn);
 294         else if (conn->cmd == SDB_CONNECTION_STORE)
 295                 status = sdb_fe_store(conn);
 296         else {
 297                 sdb_log(SDB_LOG_WARNING, "frontend: Ignoring invalid command %#x",
 298                                 conn->cmd);
 299                 sdb_strbuf_sprintf(conn->errbuf, "Invalid command %#x", conn->cmd);
 300                 status = -1;
 301         }
 302
 303         if (status) {
 304                 if (! sdb_strbuf_len(conn->errbuf))
 305                         sdb_strbuf_sprintf(conn->errbuf, "Failed to execute command");
 306                 sdb_connection_send(conn, SDB_CONNECTION_ERROR,
 307                                 (uint32_t)sdb_strbuf_len(conn->errbuf),
 308                                 sdb_strbuf_string(conn->errbuf));
 309         }
 310         return status;
 311 } /* command_handle */
 312
 313 /* initialize the connection state information */
 314 static int
 315 command_init(sdb_conn_t *conn)
 316 {
 317         const char *errmsg = NULL;
 318
 319         assert(conn && (conn->cmd == SDB_CONNECTION_IDLE) && (! conn->cmd_len));
 320
 321         if (conn->skip_len)
 322                 return -1;
 323
 324         /* reset */
 325         sdb_strbuf_clear(conn->errbuf);
 326
 327         if (sdb_proto_unmarshal_header(SDB_STRBUF_STR(conn->buf),
 328                                 &conn->cmd, &conn->cmd_len) < 0)
 329                 return -1;
 330         sdb_strbuf_skip(conn->buf, 0, 2 * sizeof(uint32_t));
 331
 332         if ((! conn->ready) && (conn->cmd != SDB_CONNECTION_STARTUP))
 333                 errmsg = "Authentication required";
 334         else if (conn->cmd == SDB_CONNECTION_IDLE)
 335                 errmsg = "Invalid command 0";
 336
 337         if (errmsg) {
 338                 size_t len = sdb_strbuf_len(conn->buf);
 339
 340                 sdb_strbuf_sprintf(conn->errbuf, "%s", errmsg);
 341                 sdb_connection_send(conn, SDB_CONNECTION_ERROR,
 342                                 (uint32_t)strlen(errmsg), errmsg);
 343                 conn->skip_len += conn->cmd_len;
 344                 conn->cmd = SDB_CONNECTION_IDLE;
 345                 conn->cmd_len = 0;
 346
 347                 if (len > conn->skip_len)
 348                         len = conn->skip_len;
 349                 sdb_strbuf_skip(conn->buf, 0, len);
 350                 conn->skip_len -= len;
 351                 /* connection_read will handle anything else */
 352         }
 353         return 0;
 354 } /* command_init */
 355
 356 /* returns negative value on error, 0 on EOF, number of octets else */
 357 static ssize_t
 358 connection_read(sdb_conn_t *conn)
 359 {
 360         ssize_t n = 0;
 361
 362         if ((! conn) || (conn->fd < 0))
 363                 return -1;
 364
 365         while (42) {
 366                 ssize_t status;
 367
 368                 errno = 0;
 369                 status = conn->read(conn, 1024);
 370                 if (status < 0) {
 371                         if ((errno == EAGAIN) || (errno == EWOULDBLOCK))
 372                                 break;
 373
 374                         sdb_connection_close(conn);
 375                         return (int)status;
 376                 }
 377                 else if (! status) /* EOF */
 378                         break;
 379
 380                 if (conn->skip_len) {
 381                         size_t len = (size_t)status < conn->skip_len
 382                                 ? (size_t)status : conn->skip_len;
 383                         sdb_strbuf_skip(conn->buf, 0, len);
 384                         conn->skip_len -= len;
 385                 }
 386
 387                 n += status;
 388
 389                 /* give the main loop a chance to execute commands (and free up buffer
 390                  * space) on large amounts of incoming traffic */
 391                 if (n > 1024 * 1024)
 392                         break;
 393         }
 394
 395         return n;
 396 } /* connection_read */
 397
 398 /*
 399  * public API
 400  */
 401
 402 int
 403 sdb_connection_enable_logging(void)
 404 {
 405         return sdb_plugin_register_log("connection-logger", connection_log,
 406                         /* user_data = */ NULL);
 407 } /* sdb_connection_enable_logging */
 408
 409 sdb_conn_t *
 410 sdb_connection_accept(int fd)
 411 {
 412         if (fd < 0)
 413                 return NULL;
 414
 415         /* the placeholder will be replaced with the accepted file
 416          * descriptor when initializing the object */
 417         return CONN(sdb_object_create(CONN_FD_PREFIX CONN_FD_PLACEHOLDER,
 418                                 connection_type, fd));
 419 } /* sdb_connection_create */
 420
 421 void
 422 sdb_connection_close(sdb_conn_t *conn)
 423 {
 424         if (! conn)
 425                 return;
 426
 427         if (conn->finish)
 428                 conn->finish(conn);
 429         conn->finish = NULL;
 430
 431         /* close the connection even if someone else still references it */
 432         if (conn->fd >= 0)
 433                 close(conn->fd);
 434         conn->fd = -1;
 435 } /* sdb_connection_close */
 436
 437 ssize_t
 438 sdb_connection_handle(sdb_conn_t *conn)
 439 {
 440         ssize_t n = 0;
 441
 442         sdb_conn_set_ctx(conn);
 443
 444         while (42) {
 445                 ssize_t status = connection_read(conn);
 446
 447                 if ((conn->cmd == SDB_CONNECTION_IDLE) && (! conn->cmd_len)
 448                                 && (sdb_strbuf_len(conn->buf) >= 2 * sizeof(int32_t)))
 449                         command_init(conn);
 450                 if ((conn->cmd != SDB_CONNECTION_IDLE)
 451                                 && (sdb_strbuf_len(conn->buf) >= conn->cmd_len)) {
 452                         command_handle(conn);
 453
 454                         /* remove the command from the buffer */
 455                         if (conn->cmd_len)
 456                                 sdb_strbuf_skip(conn->buf, 0, conn->cmd_len);
 457                         conn->cmd = SDB_CONNECTION_IDLE;
 458                         conn->cmd_len = 0;
 459                 }
 460
 461                 if (status <= 0)
 462                         break;
 463
 464                 n += status;
 465         }
 466
 467         sdb_conn_set_ctx(NULL);
 468         return n;
 469 } /* sdb_connection_handle */
 470
 471 ssize_t
 472 sdb_connection_send(sdb_conn_t *conn, uint32_t code,
 473                 uint32_t msg_len, const char *msg)
 474 {
 475         char buf[2 * sizeof(uint32_t) + msg_len];
 476         ssize_t status;
 477
 478         if ((! conn) || (conn->fd < 0))
 479                 return -1;
 480         if (sdb_proto_marshal(buf, sizeof(buf), code, msg_len, msg) < 0)
 481                 return -1;
 482
 483         status = conn->write(conn, buf, sizeof(buf));
 484         if (status < 0) {
 485                 char errbuf[1024];
 486
 487                 /* tell other code that there was a problem and, more importantly,
 488                  * make sure we don't try to send further logs to the connection */
 489                 sdb_connection_close(conn);
 490                 conn->ready = 0;
 491
 492                 sdb_log(SDB_LOG_ERR, "frontend: Failed to send msg "
 493                                 "(code: %u, len: %u) to client: %s", code, msg_len,
 494                                 sdb_strerror(errno, errbuf, sizeof(errbuf)));
 495         }
 496         return status;
 497 } /* sdb_connection_send */
 498
 499 int
 500 sdb_connection_ping(sdb_conn_t *conn)
 501 {
 502         if ((! conn) || (conn->cmd != SDB_CONNECTION_PING))
 503                 return -1;
 504
 505         /* we're alive */
 506         sdb_connection_send(conn, SDB_CONNECTION_OK, 0, NULL);
 507         return 0;
 508 } /* sdb_connection_ping */
 509
 510 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */
 511