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_strbuf_sprintf(conn->errbuf, errmsg);
 269                 sdb_connection_send(conn, CONNECTION_ERROR,
 270                                 (uint32_t)strlen(errmsg), errmsg);
 271                 return -1;
 272         }
 273
 274         switch (conn->cmd) {
 275                 case CONNECTION_PING:
 276                         status = sdb_connection_ping(conn);
 277                         break;
 278                 case CONNECTION_STARTUP:
 279                         status = sdb_fe_session_start(conn);
 280                         break;
 281
 282                 case CONNECTION_QUERY:
 283                 {
 284                         sdb_llist_t *parsetree;
 285                         sdb_conn_node_t *node = NULL;
 286
 287                         parsetree = sdb_fe_parse(sdb_strbuf_string(conn->buf),
 288                                         (int)conn->cmd_len);
 289                         if (! parsetree) {
 290                                 sdb_log(SDB_LOG_ERR, "frontend: Failed to parse query '%s'",
 291                                                 sdb_strbuf_string(conn->buf));
 292                                 status = -1;
 293                                 break;
 294                         }
 295
 296                         switch (sdb_llist_len(parsetree)) {
 297                                 case 0:
 298                                         /* skipping empty command */
 299                                         break;
 300                                 case 1:
 301                                         node = SDB_CONN_NODE(sdb_llist_get(parsetree, 0));
 302                                         break;
 303
 304                                 default:
 305                                         sdb_log(SDB_LOG_WARNING, "frontend: Ignoring %d command%s "
 306                                                         "in multi-statement query '%s'",
 307                                                         sdb_llist_len(parsetree) - 1,
 308                                                         sdb_llist_len(parsetree) == 2 ? "" : "s",
 309                                                         sdb_strbuf_string(conn->buf));
 310                                         node = SDB_CONN_NODE(sdb_llist_get(parsetree, 0));
 311                         }
 312
 313                         if (node) {
 314                                 status = sdb_fe_exec(conn, node);
 315                                 sdb_object_deref(SDB_OBJ(node));
 316                         }
 317
 318                         sdb_llist_destroy(parsetree);
 319                         break;
 320                 }
 321
 322                 case CONNECTION_FETCH:
 323                         status = sdb_fe_fetch(conn, sdb_strbuf_string(conn->buf));
 324                         break;
 325                 case CONNECTION_LIST:
 326                         status = sdb_fe_list(conn);
 327                         break;
 328                 case CONNECTION_LOOKUP:
 329                 {
 330                         sdb_store_matcher_t *m;
 331
 332                         m = sdb_fe_parse_matcher(sdb_strbuf_string(conn->buf),
 333                                         (int)conn->cmd_len);
 334                         if (! m) {
 335                                 sdb_log(SDB_LOG_ERR, "frontend: Failed to parse expression '%s'",
 336                                                 sdb_strbuf_string(conn->buf));
 337                                 status = -1;
 338                                 break;
 339                         }
 340
 341                         status = sdb_fe_lookup(conn, m);
 342                         sdb_object_deref(SDB_OBJ(m));
 343                         break;
 344                 }
 345
 346                 default:
 347                 {
 348                         sdb_log(SDB_LOG_WARNING, "frontend: Ignoring invalid command %#x",
 349                                         conn->cmd);
 350                         sdb_strbuf_sprintf(conn->errbuf, "Invalid command %#x", conn->cmd);
 351                         status = -1;
 352                         break;
 353                 }
 354         }
 355
 356         if (status)
 357                 sdb_connection_send(conn, CONNECTION_ERROR,
 358                                 (uint32_t)sdb_strbuf_len(conn->errbuf),
 359                                 sdb_strbuf_string(conn->errbuf));
 360         return status;
 361 } /* command_handle */
 362
 363 /* initialize the connection state information */
 364 static int
 365 command_init(sdb_conn_t *conn)
 366 {
 367         size_t len;
 368
 369         assert(conn && (conn->cmd == CONNECTION_IDLE) && (! conn->cmd_len));
 370
 371         /* reset */
 372         sdb_strbuf_sprintf(conn->errbuf, "");
 373
 374         conn->cmd = connection_get_int32(conn, 0);
 375         conn->cmd_len = connection_get_int32(conn, sizeof(uint32_t));
 376
 377         len = 2 * sizeof(uint32_t);
 378         if (conn->cmd == CONNECTION_IDLE)
 379                 len += conn->cmd_len;
 380         sdb_strbuf_skip(conn->buf, 0, len);
 381         return 0;
 382 } /* command_init */
 383
 384 /* returns negative value on error, 0 on EOF, number of octets else */
 385 static ssize_t
 386 connection_read(sdb_conn_t *conn)
 387 {
 388         ssize_t n = 0;
 389
 390         if ((! conn) || (conn->fd < 0))
 391                 return -1;
 392
 393         while (42) {
 394                 ssize_t status;
 395
 396                 errno = 0;
 397                 status = sdb_strbuf_read(conn->buf, conn->fd, 1024);
 398                 if (status < 0) {
 399                         if ((errno == EAGAIN) || (errno == EWOULDBLOCK))
 400                                 break;
 401
 402                         close(conn->fd);
 403                         conn->fd = -1;
 404                         return (int)status;
 405                 }
 406                 else if (! status) /* EOF */
 407                         break;
 408
 409                 n += status;
 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)
 428 {
 429         if (fd < 0)
 430                 return NULL;
 431
 432         /* the placeholder will be replaced with the accepted file
 433          * descriptor when initializing the object */
 434         return CONN(sdb_object_create(CONN_FD_PREFIX CONN_FD_PLACEHOLDER,
 435                                 connection_type, fd));
 436 } /* sdb_connection_create */
 437
 438 void
 439 sdb_connection_close(sdb_conn_t *conn)
 440 {
 441         if (! conn)
 442                 return;
 443
 444         /* close the connection even if someone else still references it */
 445         if (conn->fd >= 0)
 446                 close(conn->fd);
 447         conn->fd = -1;
 448
 449         sdb_object_deref(SDB_OBJ(conn));
 450 } /* sdb_connection_close */
 451
 452 ssize_t
 453 sdb_connection_read(sdb_conn_t *conn)
 454 {
 455         ssize_t n = 0;
 456
 457         sdb_conn_set_ctx(conn);
 458
 459         while (42) {
 460                 ssize_t status = connection_read(conn);
 461
 462                 if ((conn->cmd == CONNECTION_IDLE) && (! conn->cmd_len)
 463                                 && (sdb_strbuf_len(conn->buf) >= 2 * sizeof(int32_t)))
 464                         command_init(conn);
 465                 if ((conn->cmd != CONNECTION_IDLE)
 466                                 && (sdb_strbuf_len(conn->buf) >= conn->cmd_len)) {
 467                         command_handle(conn);
 468
 469                         /* remove the command from the buffer */
 470                         if (conn->cmd_len)
 471                                 sdb_strbuf_skip(conn->buf, 0, conn->cmd_len);
 472                         conn->cmd = CONNECTION_IDLE;
 473                         conn->cmd_len = 0;
 474                 }
 475
 476                 if (status <= 0)
 477                         break;
 478
 479                 n += status;
 480         }
 481
 482         sdb_conn_set_ctx(NULL);
 483         return n;
 484 } /* sdb_connection_read */
 485
 486 ssize_t
 487 sdb_connection_send(sdb_conn_t *conn, uint32_t code,
 488                 uint32_t msg_len, const char *msg)
 489 {
 490         ssize_t status;
 491
 492         if ((! conn) || (conn->fd < 0))
 493                 return -1;
 494
 495         status = sdb_proto_send_msg(conn->fd, code, msg_len, msg);
 496         if (status < 0) {
 497                 char errbuf[1024];
 498
 499                 /* tell other code that there was a problem and, more importantly,
 500                  * make sure we don't try to send further logs to the connection */
 501                 close(conn->fd);
 502                 conn->fd = -1;
 503
 504                 sdb_log(SDB_LOG_ERR, "frontend: Failed to send msg "
 505                                 "(code: %u, len: %u) to client: %s", code, msg_len,
 506                                 sdb_strerror(errno, errbuf, sizeof(errbuf)));
 507         }
 508         return status;
 509 } /* sdb_connection_send */
 510
 511 int
 512 sdb_connection_ping(sdb_conn_t *conn)
 513 {
 514         if ((! conn) || (conn->cmd != CONNECTION_PING))
 515                 return -1;
 516
 517         /* we're alive */
 518         sdb_connection_send(conn, CONNECTION_OK, 0, NULL);
 519         return 0;
 520 } /* sdb_connection_ping */
 521
 522 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */
 523