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 #include "sysdb.h"
  29 #include "core/object.h"
  30 #include "core/plugin.h"
  31 #include "frontend/connection-private.h"
  32 #include "frontend/parser.h"
  33 #include "utils/error.h"
  34 #include "utils/strbuf.h"
  35 #include "utils/proto.h"
  36
  37 #include <assert.h>
  38 #include <errno.h>
  39
  40 #include <arpa/inet.h>
  41 #include <fcntl.h>
  42
  43 #include <stdlib.h>
  44 #include <string.h>
  45
  46 #include <pthread.h>
  47
  48 /*
  49  * private variables
  50  */
  51
  52 static pthread_key_t conn_ctx_key;
  53 static _Bool         conn_ctx_key_initialized = 0;
  54
  55 /*
  56  * private types
  57  */
  58
  59 /* name of connection objects */
  60 #define CONN_FD_PREFIX "conn#"
  61 #define CONN_FD_PLACEHOLDER "XXXXXXX"
  62
  63 static int
  64 connection_init(sdb_object_t *obj, va_list ap)
  65 {
  66         sdb_conn_t *conn;
  67         int sock_fd;
  68         int sock_fl;
  69
  70         assert(obj);
  71         conn = CONN(obj);
  72
  73         sock_fd = va_arg(ap, int);
  74
  75         conn->buf = sdb_strbuf_create(/* size = */ 128);
  76         if (! conn->buf) {
  77                 sdb_log(SDB_LOG_ERR, "frontend: Failed to allocate a read buffer "
  78                                 "for a new connection");
  79                 return -1;
  80         }
  81         conn->errbuf = sdb_strbuf_create(0);
  82         if (! conn->errbuf) {
  83                 sdb_log(SDB_LOG_ERR, "frontend: Failed to allocate an error buffer "
  84                                 "for a new connection");
  85                 return -1;
  86         }
  87
  88         conn->client_addr_len = sizeof(conn->client_addr);
  89         conn->fd = accept(sock_fd, (struct sockaddr *)&conn->client_addr,
  90                         &conn->client_addr_len);
  91
  92         if (conn->fd < 0) {
  93                 char buf[1024];
  94                 sdb_log(SDB_LOG_ERR, "frontend: Failed to accept remote "
  95                                 "connection: %s", sdb_strerror(errno,
  96                                         buf, sizeof(buf)));
  97                 return -1;
  98         }
  99
 100         if (conn->client_addr.ss_family != AF_UNIX) {
 101                 sdb_log(SDB_LOG_ERR, "frontend: Accepted connection using "
 102                                 "unexpected family type %d", conn->client_addr.ss_family);
 103                 return -1;
 104         }
 105
 106         sock_fl = fcntl(conn->fd, F_GETFL);
 107         if (fcntl(conn->fd, F_SETFL, sock_fl | O_NONBLOCK)) {
 108                 char buf[1024];
 109                 sdb_log(SDB_LOG_ERR, "frontend: Failed to switch connection conn#%i "
 110                                 "to non-blocking mode: %s", conn->fd,
 111                                 sdb_strerror(errno, buf, sizeof(buf)));
 112                 return -1;
 113         }
 114
 115         sdb_log(SDB_LOG_DEBUG, "frontend: Accepted connection on fd=%i",
 116                         conn->fd);
 117
 118         conn->cmd = CONNECTION_IDLE;
 119         conn->cmd_len = 0;
 120
 121         /* update the object name */
 122         snprintf(obj->name + strlen(CONN_FD_PREFIX),
 123                         strlen(CONN_FD_PLACEHOLDER), "%i", conn->fd);
 124         return 0;
 125 } /* connection_init */
 126
 127 static void
 128 connection_destroy(sdb_object_t *obj)
 129 {
 130         sdb_conn_t *conn;
 131         size_t len;
 132
 133         assert(obj);
 134         conn = CONN(obj);
 135
 136         if (conn->buf) {
 137                 len = sdb_strbuf_len(conn->buf);
 138                 if (len)
 139                         sdb_log(SDB_LOG_INFO, "frontend: Discarding incomplete command "
 140                                         "(%zu byte%s left in buffer)", len, len == 1 ? "" : "s");
 141         }
 142
 143         sdb_log(SDB_LOG_DEBUG, "frontend: Closing connection %s", obj->name);
 144         if (conn->fd >= 0)
 145                 close(conn->fd);
 146         conn->fd = -1;
 147
 148         if (conn->username)
 149                 free(conn->username);
 150         conn->username = NULL;
 151
 152         sdb_strbuf_destroy(conn->buf);
 153         conn->buf = NULL;
 154         sdb_strbuf_destroy(conn->errbuf);
 155         conn->errbuf = NULL;
 156 } /* connection_destroy */
 157
 158 static sdb_type_t connection_type = {
 159         /* size = */ sizeof(sdb_conn_t),
 160         /* init = */ connection_init,
 161         /* destroy = */ connection_destroy,
 162 };
 163
 164 /*
 165  * private helper functions
 166  */
 167
 168 static void
 169 sdb_conn_ctx_destructor(void *c)
 170 {
 171         sdb_object_t *conn = c;
 172
 173         if (! conn)
 174                 return;
 175         sdb_object_deref(conn);
 176 } /* sdb_conn_ctx_destructor */
 177
 178 static void
 179 sdb_conn_ctx_init(void)
 180 {
 181         if (conn_ctx_key_initialized)
 182                 return;
 183
 184         pthread_key_create(&conn_ctx_key, sdb_conn_ctx_destructor);
 185         conn_ctx_key_initialized = 1;
 186 } /* sdb_conn_ctx_init */
 187
 188 static void
 189 sdb_conn_set_ctx(sdb_conn_t *conn)
 190 {
 191         sdb_conn_t *old;
 192
 193         sdb_conn_ctx_init();
 194
 195         old = pthread_getspecific(conn_ctx_key);
 196         if (old)
 197                 sdb_object_deref(SDB_OBJ(old));
 198         if (conn)
 199                 sdb_object_ref(SDB_OBJ(conn));
 200         pthread_setspecific(conn_ctx_key, conn);
 201 } /* sdb_conn_set_ctx */
 202
 203 static sdb_conn_t *
 204 sdb_conn_get_ctx(void)
 205 {
 206         if (! conn_ctx_key_initialized)
 207                 return NULL;
 208         return pthread_getspecific(conn_ctx_key);
 209 } /* sdb_conn_get_ctx */
 210
 211 /*
 212  * connection handler functions
 213  */
 214
 215 /*
 216  * connection_log:
 217  * Send a log message originating from the current thread to the client.
 218  */
 219 static int
 220 connection_log(int prio, const char *msg,
 221                 sdb_object_t __attribute__((unused)) *user_data)
 222 {
 223         sdb_conn_t *conn;
 224
 225         conn = sdb_conn_get_ctx();
 226         /* no connection associated to this thread
 227          * or user not authenticated yet => don't leak any information */
 228         if ((! conn) || (! conn->username))
 229                 return 0;
 230
 231         /* XXX: make the log-level configurable by the client at runtime */
 232         if (prio >= SDB_LOG_DEBUG)
 233                 return 0;
 234
 235         /* TODO: Use CONNECTION_LOG_<prio>? */
 236         if (sdb_connection_send(conn, CONNECTION_LOG,
 237                                 (uint32_t)strlen(msg), msg) < 0)
 238                 return -1;
 239         return 0;
 240 } /* connection_log */
 241
 242 static uint32_t
 243 connection_get_int32(sdb_conn_t *conn, size_t offset)
 244 {
 245         const char *data;
 246         uint32_t n;
 247
 248         assert(conn && (sdb_strbuf_len(conn->buf) >= offset + sizeof(uint32_t)));
 249
 250         data = sdb_strbuf_string(conn->buf);
 251         memcpy(&n, data + offset, sizeof(n));
 252         n = ntohl(n);
 253         return n;
 254 } /* connection_get_int32 */
 255
 256 static int
 257 command_handle(sdb_conn_t *conn)
 258 {
 259         int status = -1;
 260
 261         assert(conn && (conn->cmd != CONNECTION_IDLE));
 262
 263         sdb_log(SDB_LOG_DEBUG, "frontend: Handling command %u (len: %u)",
 264                         conn->cmd, conn->cmd_len);
 265
 266         if ((! conn->username) && (conn->cmd != CONNECTION_STARTUP)) {
 267                 const char *errmsg = "Authentication required";
 268                 sdb_connection_send(conn, CONNECTION_ERROR,
 269                                 (uint32_t)strlen(errmsg), errmsg);
 270
 271                 /* remove the command from the buffer */
 272                 if (conn->cmd_len)
 273                         sdb_strbuf_skip(conn->buf, 0, conn->cmd_len);
 274                 return -1;
 275         }
 276
 277         /* reset */
 278         sdb_strbuf_sprintf(conn->errbuf, "");
 279
 280         switch (conn->cmd) {
 281                 case CONNECTION_PING:
 282                         status = sdb_connection_ping(conn);
 283                         break;
 284                 case CONNECTION_STARTUP:
 285                         status = sdb_fe_session_start(conn);
 286                         break;
 287
 288                 case CONNECTION_QUERY:
 289                 {
 290                         sdb_llist_t *parsetree;
 291                         sdb_conn_node_t *node = NULL;
 292
 293                         parsetree = sdb_fe_parse(sdb_strbuf_string(conn->buf),
 294                                         (int)conn->cmd_len);
 295                         if (! parsetree) {
 296                                 sdb_log(SDB_LOG_ERR, "frontend: Failed to parse query '%s'",
 297                                                 sdb_strbuf_string(conn->buf));
 298                                 status = -1;
 299                                 break;
 300                         }
 301
 302                         switch (sdb_llist_len(parsetree)) {
 303                                 case 0:
 304                                         /* skipping empty command */
 305                                         break;
 306                                 case 1:
 307                                         node = SDB_CONN_NODE(sdb_llist_get(parsetree, 0));
 308                                         break;
 309
 310                                 default:
 311                                         sdb_log(SDB_LOG_WARNING, "frontend: Ignoring %d command%s "
 312                                                         "in multi-statement query '%s'",
 313                                                         sdb_llist_len(parsetree) - 1,
 314                                                         sdb_llist_len(parsetree) == 2 ? "" : "s",
 315                                                         sdb_strbuf_string(conn->buf));
 316                                         node = SDB_CONN_NODE(sdb_llist_get(parsetree, 0));
 317                         }
 318
 319                         if (node) {
 320                                 status = sdb_fe_exec(conn, node);
 321                                 sdb_object_deref(SDB_OBJ(node));
 322                         }
 323
 324                         sdb_llist_destroy(parsetree);
 325                         break;
 326                 }
 327
 328                 case CONNECTION_FETCH:
 329                         status = sdb_fe_fetch(conn, sdb_strbuf_string(conn->buf));
 330                         break;
 331                 case CONNECTION_LIST:
 332                         status = sdb_fe_list(conn);
 333                         break;
 334                 case CONNECTION_LOOKUP:
 335                 {
 336                         sdb_store_matcher_t *m;
 337
 338                         m = sdb_fe_parse_matcher(sdb_strbuf_string(conn->buf),
 339                                         (int)conn->cmd_len);
 340                         if (! m) {
 341                                 sdb_log(SDB_LOG_ERR, "frontend: Failed to parse expression '%s'",
 342                                                 sdb_strbuf_string(conn->buf));
 343                                 status = -1;
 344                                 break;
 345                         }
 346
 347                         status = sdb_fe_lookup(conn, m);
 348                         sdb_object_deref(SDB_OBJ(m));
 349                         break;
 350                 }
 351
 352                 default:
 353                 {
 354                         sdb_log(SDB_LOG_WARNING, "frontend: Ignoring invalid command %#x",
 355                                         conn->cmd);
 356                         sdb_strbuf_sprintf(conn->errbuf, "Invalid command %#x", conn->cmd);
 357                         status = -1;
 358                         break;
 359                 }
 360         }
 361
 362         if (status)
 363                 sdb_connection_send(conn, CONNECTION_ERROR,
 364                                 (uint32_t)sdb_strbuf_len(conn->errbuf),
 365                                 sdb_strbuf_string(conn->errbuf));
 366
 367         /* remove the command from the buffer */
 368         if (conn->cmd_len)
 369                 sdb_strbuf_skip(conn->buf, 0, conn->cmd_len);
 370         conn->cmd = CONNECTION_IDLE;
 371         conn->cmd_len = 0;
 372         return status;
 373 } /* command_handle */
 374
 375 /* initialize the connection state information */
 376 static int
 377 command_init(sdb_conn_t *conn)
 378 {
 379         size_t len;
 380
 381         assert(conn && (conn->cmd == CONNECTION_IDLE) && (! conn->cmd_len));
 382
 383         conn->cmd = connection_get_int32(conn, 0);
 384         conn->cmd_len = connection_get_int32(conn, sizeof(uint32_t));
 385
 386         len = 2 * sizeof(uint32_t);
 387         if (conn->cmd == CONNECTION_IDLE)
 388                 len += conn->cmd_len;
 389         sdb_strbuf_skip(conn->buf, 0, len);
 390         return 0;
 391 } /* command_init */
 392
 393 /* returns negative value on error, 0 on EOF, number of octets else */
 394 static ssize_t
 395 connection_read(sdb_conn_t *conn)
 396 {
 397         ssize_t n = 0;
 398
 399         if ((! conn) || (conn->fd < 0))
 400                 return -1;
 401
 402         while (42) {
 403                 ssize_t status;
 404
 405                 errno = 0;
 406                 status = sdb_strbuf_read(conn->buf, conn->fd, 1024);
 407                 if (status < 0) {
 408                         if ((errno == EAGAIN) || (errno == EWOULDBLOCK))
 409                                 break;
 410
 411                         close(conn->fd);
 412                         conn->fd = -1;
 413                         return (int)status;
 414                 }
 415                 else if (! status) /* EOF */
 416                         break;
 417
 418                 n += status;
 419         }
 420
 421         return n;
 422 } /* connection_read */
 423
 424 /*
 425  * public API
 426  */
 427
 428 int
 429 sdb_connection_enable_logging(void)
 430 {
 431         return sdb_plugin_register_log("connection-logger", connection_log,
 432                         /* user_data = */ NULL);
 433 } /* sdb_connection_enable_logging */
 434
 435 sdb_conn_t *
 436 sdb_connection_accept(int fd)
 437 {
 438         if (fd < 0)
 439                 return NULL;
 440
 441         /* the placeholder will be replaced with the accepted file
 442          * descriptor when initializing the object */
 443         return CONN(sdb_object_create(CONN_FD_PREFIX CONN_FD_PLACEHOLDER,
 444                                 connection_type, fd));
 445 } /* sdb_connection_create */
 446
 447 void
 448 sdb_connection_close(sdb_conn_t *conn)
 449 {
 450         if (! conn)
 451                 return;
 452
 453         /* close the connection even if someone else still references it */
 454         if (conn->fd >= 0)
 455                 close(conn->fd);
 456         conn->fd = -1;
 457
 458         sdb_object_deref(SDB_OBJ(conn));
 459 } /* sdb_connection_close */
 460
 461 ssize_t
 462 sdb_connection_read(sdb_conn_t *conn)
 463 {
 464         ssize_t n = 0;
 465
 466         sdb_conn_set_ctx(conn);
 467
 468         while (42) {
 469                 ssize_t status = connection_read(conn);
 470
 471                 if ((conn->cmd == CONNECTION_IDLE) && (! conn->cmd_len)
 472                                 && (sdb_strbuf_len(conn->buf) >= 2 * sizeof(int32_t)))
 473                         command_init(conn);
 474                 if ((conn->cmd != CONNECTION_IDLE)
 475                                 && (sdb_strbuf_len(conn->buf) >= conn->cmd_len))
 476                         command_handle(conn);
 477
 478                 if (status <= 0)
 479                         break;
 480
 481                 n += status;
 482         }
 483
 484         sdb_conn_set_ctx(NULL);
 485         return n;
 486 } /* sdb_connection_read */
 487
 488 ssize_t
 489 sdb_connection_send(sdb_conn_t *conn, uint32_t code,
 490                 uint32_t msg_len, const char *msg)
 491 {
 492         ssize_t status;
 493
 494         if ((! conn) || (conn->fd < 0))
 495                 return -1;
 496
 497         status = sdb_proto_send_msg(conn->fd, code, msg_len, msg);
 498         if (status < 0) {
 499                 char errbuf[1024];
 500
 501                 /* tell other code that there was a problem and, more importantly,
 502                  * make sure we don't try to send further logs to the connection */
 503                 close(conn->fd);
 504                 conn->fd = -1;
 505
 506                 sdb_log(SDB_LOG_ERR, "frontend: Failed to send msg "
 507                                 "(code: %u, len: %u) to client: %s", code, msg_len,
 508                                 sdb_strerror(errno, errbuf, sizeof(errbuf)));
 509         }
 510         return status;
 511 } /* sdb_connection_send */
 512
 513 int
 514 sdb_connection_ping(sdb_conn_t *conn)
 515 {
 516         if ((! conn) || (conn->cmd != CONNECTION_PING))
 517                 return -1;
 518
 519         /* we're alive */
 520         sdb_connection_send(conn, CONNECTION_OK, 0, NULL);
 521         return 0;
 522 } /* sdb_connection_ping */
 523
 524 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */
 525