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         conn->skip_len = 0;
 121
 122         /* update the object name */
 123         snprintf(obj->name + strlen(CONN_FD_PREFIX),
 124                         strlen(CONN_FD_PLACEHOLDER), "%i", conn->fd);
 125         return 0;
 126 } /* connection_init */
 127
 128 static void
 129 connection_destroy(sdb_object_t *obj)
 130 {
 131         sdb_conn_t *conn;
 132         size_t len;
 133
 134         assert(obj);
 135         conn = CONN(obj);
 136
 137         if (conn->buf) {
 138                 len = sdb_strbuf_len(conn->buf);
 139                 if (len)
 140                         sdb_log(SDB_LOG_INFO, "frontend: Discarding incomplete command "
 141                                         "(%zu byte%s left in buffer)", len, len == 1 ? "" : "s");
 142         }
 143
 144         sdb_log(SDB_LOG_DEBUG, "frontend: Closing connection %s", obj->name);
 145         if (conn->fd >= 0)
 146                 close(conn->fd);
 147         conn->fd = -1;
 148
 149         if (conn->username)
 150                 free(conn->username);
 151         conn->username = NULL;
 152
 153         sdb_strbuf_destroy(conn->buf);
 154         conn->buf = NULL;
 155         sdb_strbuf_destroy(conn->errbuf);
 156         conn->errbuf = NULL;
 157 } /* connection_destroy */
 158
 159 static sdb_type_t connection_type = {
 160         /* size = */ sizeof(sdb_conn_t),
 161         /* init = */ connection_init,
 162         /* destroy = */ connection_destroy,
 163 };
 164
 165 /*
 166  * private helper functions
 167  */
 168
 169 static void
 170 sdb_conn_ctx_destructor(void *c)
 171 {
 172         sdb_object_t *conn = c;
 173
 174         if (! conn)
 175                 return;
 176         sdb_object_deref(conn);
 177 } /* sdb_conn_ctx_destructor */
 178
 179 static void
 180 sdb_conn_ctx_init(void)
 181 {
 182         if (conn_ctx_key_initialized)
 183                 return;
 184
 185         pthread_key_create(&conn_ctx_key, sdb_conn_ctx_destructor);
 186         conn_ctx_key_initialized = 1;
 187 } /* sdb_conn_ctx_init */
 188
 189 static void
 190 sdb_conn_set_ctx(sdb_conn_t *conn)
 191 {
 192         sdb_conn_t *old;
 193
 194         sdb_conn_ctx_init();
 195
 196         old = pthread_getspecific(conn_ctx_key);
 197         if (old)
 198                 sdb_object_deref(SDB_OBJ(old));
 199         if (conn)
 200                 sdb_object_ref(SDB_OBJ(conn));
 201         pthread_setspecific(conn_ctx_key, conn);
 202 } /* sdb_conn_set_ctx */
 203
 204 static sdb_conn_t *
 205 sdb_conn_get_ctx(void)
 206 {
 207         if (! conn_ctx_key_initialized)
 208                 return NULL;
 209         return pthread_getspecific(conn_ctx_key);
 210 } /* sdb_conn_get_ctx */
 211
 212 /*
 213  * connection handler functions
 214  */
 215
 216 /*
 217  * connection_log:
 218  * Send a log message originating from the current thread to the client.
 219  */
 220 static int
 221 connection_log(int prio, const char *msg,
 222                 sdb_object_t __attribute__((unused)) *user_data)
 223 {
 224         sdb_conn_t *conn;
 225
 226         conn = sdb_conn_get_ctx();
 227         /* no connection associated to this thread
 228          * or user not authenticated yet => don't leak any information */
 229         if ((! conn) || (! conn->username))
 230                 return 0;
 231
 232         /* XXX: make the log-level configurable by the client at runtime */
 233         if (prio >= SDB_LOG_DEBUG)
 234                 return 0;
 235
 236         /* TODO: Use CONNECTION_LOG_<prio>? */
 237         if (sdb_connection_send(conn, CONNECTION_LOG,
 238                                 (uint32_t)strlen(msg), msg) < 0)
 239                 return -1;
 240         return 0;
 241 } /* connection_log */
 242
 243 static uint32_t
 244 connection_get_int32(sdb_conn_t *conn, size_t offset)
 245 {
 246         const char *data;
 247         uint32_t n;
 248
 249         assert(conn && (sdb_strbuf_len(conn->buf) >= offset + sizeof(uint32_t)));
 250
 251         data = sdb_strbuf_string(conn->buf);
 252         memcpy(&n, data + offset, sizeof(n));
 253         n = ntohl(n);
 254         return n;
 255 } /* connection_get_int32 */
 256
 257 static int
 258 command_handle(sdb_conn_t *conn)
 259 {
 260         int status = -1;
 261
 262         assert(conn && (conn->cmd != CONNECTION_IDLE));
 263         assert(! conn->skip_len);
 264
 265         sdb_log(SDB_LOG_DEBUG, "frontend: Handling command %u (len: %u)",
 266                         conn->cmd, conn->cmd_len);
 267
 268         if ((! conn->username) && (conn->cmd != CONNECTION_STARTUP)) {
 269                 const char *errmsg = "Authentication required";
 270                 sdb_strbuf_sprintf(conn->errbuf, errmsg);
 271                 sdb_connection_send(conn, CONNECTION_ERROR,
 272                                 (uint32_t)strlen(errmsg), errmsg);
 273                 return -1;
 274         }
 275
 276         switch (conn->cmd) {
 277                 case CONNECTION_PING:
 278                         status = sdb_connection_ping(conn);
 279                         break;
 280                 case CONNECTION_STARTUP:
 281                         status = sdb_fe_session_start(conn);
 282                         break;
 283
 284                 case CONNECTION_QUERY:
 285                 {
 286                         sdb_llist_t *parsetree;
 287                         sdb_conn_node_t *node = NULL;
 288
 289                         parsetree = sdb_fe_parse(sdb_strbuf_string(conn->buf),
 290                                         (int)conn->cmd_len);
 291                         if (! parsetree) {
 292                                 sdb_log(SDB_LOG_ERR, "frontend: Failed to parse query '%s'",
 293                                                 sdb_strbuf_string(conn->buf));
 294                                 status = -1;
 295                                 break;
 296                         }
 297
 298                         switch (sdb_llist_len(parsetree)) {
 299                                 case 0:
 300                                         /* skipping empty command */
 301                                         break;
 302                                 case 1:
 303                                         node = SDB_CONN_NODE(sdb_llist_get(parsetree, 0));
 304                                         break;
 305
 306                                 default:
 307                                         sdb_log(SDB_LOG_WARNING, "frontend: Ignoring %d command%s "
 308                                                         "in multi-statement query '%s'",
 309                                                         sdb_llist_len(parsetree) - 1,
 310                                                         sdb_llist_len(parsetree) == 2 ? "" : "s",
 311                                                         sdb_strbuf_string(conn->buf));
 312                                         node = SDB_CONN_NODE(sdb_llist_get(parsetree, 0));
 313                         }
 314
 315                         if (node) {
 316                                 status = sdb_fe_exec(conn, node);
 317                                 sdb_object_deref(SDB_OBJ(node));
 318                         }
 319
 320                         sdb_llist_destroy(parsetree);
 321                         break;
 322                 }
 323
 324                 case CONNECTION_FETCH:
 325                         status = sdb_fe_fetch(conn, sdb_strbuf_string(conn->buf));
 326                         break;
 327                 case CONNECTION_LIST:
 328                         status = sdb_fe_list(conn);
 329                         break;
 330                 case CONNECTION_LOOKUP:
 331                 {
 332                         sdb_store_matcher_t *m;
 333
 334                         m = sdb_fe_parse_matcher(sdb_strbuf_string(conn->buf),
 335                                         (int)conn->cmd_len);
 336                         if (! m) {
 337                                 sdb_log(SDB_LOG_ERR, "frontend: Failed to parse expression '%s'",
 338                                                 sdb_strbuf_string(conn->buf));
 339                                 status = -1;
 340                                 break;
 341                         }
 342
 343                         status = sdb_fe_lookup(conn, m);
 344                         sdb_object_deref(SDB_OBJ(m));
 345                         break;
 346                 }
 347
 348                 default:
 349                 {
 350                         sdb_log(SDB_LOG_WARNING, "frontend: Ignoring invalid command %#x",
 351                                         conn->cmd);
 352                         sdb_strbuf_sprintf(conn->errbuf, "Invalid command %#x", conn->cmd);
 353                         status = -1;
 354                         break;
 355                 }
 356         }
 357
 358         if (status)
 359                 sdb_connection_send(conn, CONNECTION_ERROR,
 360                                 (uint32_t)sdb_strbuf_len(conn->errbuf),
 361                                 sdb_strbuf_string(conn->errbuf));
 362         return status;
 363 } /* command_handle */
 364
 365 /* initialize the connection state information */
 366 static int
 367 command_init(sdb_conn_t *conn)
 368 {
 369         size_t len;
 370
 371         assert(conn && (conn->cmd == CONNECTION_IDLE) && (! conn->cmd_len));
 372
 373         if (conn->skip_len)
 374                 return -1;
 375
 376         /* reset */
 377         sdb_strbuf_sprintf(conn->errbuf, "");
 378
 379         conn->cmd = connection_get_int32(conn, 0);
 380         conn->cmd_len = connection_get_int32(conn, sizeof(uint32_t));
 381
 382         if (conn->cmd == CONNECTION_IDLE) {
 383                 const char *errmsg = "Invalid command 0";
 384                 sdb_strbuf_sprintf(conn->errbuf, errmsg);
 385                 sdb_connection_send(conn, CONNECTION_ERROR,
 386                                 (uint32_t)strlen(errmsg), errmsg);
 387                 conn->skip_len += conn->cmd_len;
 388                 conn->cmd_len = 0;
 389         }
 390         sdb_strbuf_skip(conn->buf, 0, 2 * sizeof(uint32_t));
 391
 392         if (conn->skip_len) {
 393                 len = sdb_strbuf_len(conn->buf);
 394                 if (len > conn->skip_len)
 395                         len = conn->skip_len;
 396                 sdb_strbuf_skip(conn->buf, 0, len);
 397                 conn->skip_len -= len;
 398                 /* connection_read will handle anything else */
 399         }
 400         return 0;
 401 } /* command_init */
 402
 403 /* returns negative value on error, 0 on EOF, number of octets else */
 404 static ssize_t
 405 connection_read(sdb_conn_t *conn)
 406 {
 407         ssize_t n = 0;
 408
 409         if ((! conn) || (conn->fd < 0))
 410                 return -1;
 411
 412         while (42) {
 413                 ssize_t status;
 414
 415                 errno = 0;
 416                 status = sdb_strbuf_read(conn->buf, conn->fd, 1024);
 417                 if (status < 0) {
 418                         if ((errno == EAGAIN) || (errno == EWOULDBLOCK))
 419                                 break;
 420
 421                         close(conn->fd);
 422                         conn->fd = -1;
 423                         return (int)status;
 424                 }
 425                 else if (! status) /* EOF */
 426                         break;
 427
 428                 if (conn->skip_len) {
 429                         size_t len = (size_t)status < conn->skip_len
 430                                 ? (size_t)status : conn->skip_len;
 431                         sdb_strbuf_skip(conn->buf, 0, len);
 432                         conn->skip_len -= len;
 433                 }
 434
 435                 n += status;
 436         }
 437
 438         return n;
 439 } /* connection_read */
 440
 441 /*
 442  * public API
 443  */
 444
 445 int
 446 sdb_connection_enable_logging(void)
 447 {
 448         return sdb_plugin_register_log("connection-logger", connection_log,
 449                         /* user_data = */ NULL);
 450 } /* sdb_connection_enable_logging */
 451
 452 sdb_conn_t *
 453 sdb_connection_accept(int fd)
 454 {
 455         if (fd < 0)
 456                 return NULL;
 457
 458         /* the placeholder will be replaced with the accepted file
 459          * descriptor when initializing the object */
 460         return CONN(sdb_object_create(CONN_FD_PREFIX CONN_FD_PLACEHOLDER,
 461                                 connection_type, fd));
 462 } /* sdb_connection_create */
 463
 464 void
 465 sdb_connection_close(sdb_conn_t *conn)
 466 {
 467         if (! conn)
 468                 return;
 469
 470         /* close the connection even if someone else still references it */
 471         if (conn->fd >= 0)
 472                 close(conn->fd);
 473         conn->fd = -1;
 474
 475         sdb_object_deref(SDB_OBJ(conn));
 476 } /* sdb_connection_close */
 477
 478 ssize_t
 479 sdb_connection_read(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 == CONNECTION_IDLE) && (! conn->cmd_len)
 489                                 && (sdb_strbuf_len(conn->buf) >= 2 * sizeof(int32_t)))
 490                         command_init(conn);
 491                 if ((conn->cmd != 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 = 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_read */
 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         ssize_t status;
 517
 518         if ((! conn) || (conn->fd < 0))
 519                 return -1;
 520
 521         status = sdb_proto_send_msg(conn->fd, code, msg_len, msg);
 522         if (status < 0) {
 523                 char errbuf[1024];
 524
 525                 /* tell other code that there was a problem and, more importantly,
 526                  * make sure we don't try to send further logs to the connection */
 527                 close(conn->fd);
 528                 conn->fd = -1;
 529
 530                 sdb_log(SDB_LOG_ERR, "frontend: Failed to send msg "
 531                                 "(code: %u, len: %u) to client: %s", code, msg_len,
 532                                 sdb_strerror(errno, errbuf, sizeof(errbuf)));
 533         }
 534         return status;
 535 } /* sdb_connection_send */
 536
 537 int
 538 sdb_connection_ping(sdb_conn_t *conn)
 539 {
 540         if ((! conn) || (conn->cmd != CONNECTION_PING))
 541                 return -1;
 542
 543         /* we're alive */
 544         sdb_connection_send(conn, CONNECTION_OK, 0, NULL);
 545         return 0;
 546 } /* sdb_connection_ping */
 547
 548 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */
 549