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 on fd=%i",
 144                         conn->fd);
 145         if (conn->fd >= 0)
 146                 close(conn->fd);
 147         conn->fd = -1;
 148
 149         sdb_strbuf_destroy(conn->buf);
 150         conn->buf = NULL;
 151         sdb_strbuf_destroy(conn->errbuf);
 152         conn->errbuf = NULL;
 153 } /* connection_destroy */
 154
 155 static sdb_type_t connection_type = {
 156         /* size = */ sizeof(sdb_conn_t),
 157         /* init = */ connection_init,
 158         /* destroy = */ connection_destroy,
 159 };
 160
 161 /*
 162  * private helper functions
 163  */
 164
 165 static void
 166 sdb_conn_ctx_destructor(void *c)
 167 {
 168         sdb_object_t *conn = c;
 169
 170         if (! conn)
 171                 return;
 172         sdb_object_deref(conn);
 173 } /* sdb_conn_ctx_destructor */
 174
 175 static void
 176 sdb_conn_ctx_init(void)
 177 {
 178         if (conn_ctx_key_initialized)
 179                 return;
 180
 181         pthread_key_create(&conn_ctx_key, sdb_conn_ctx_destructor);
 182         conn_ctx_key_initialized = 1;
 183 } /* sdb_conn_ctx_init */
 184
 185 static void
 186 sdb_conn_set_ctx(sdb_conn_t *conn)
 187 {
 188         sdb_conn_ctx_init();
 189         if (conn)
 190                 sdb_object_ref(SDB_OBJ(conn));
 191         pthread_setspecific(conn_ctx_key, conn);
 192 } /* sdb_conn_set_ctx */
 193
 194 static sdb_conn_t *
 195 sdb_conn_get_ctx(void)
 196 {
 197         if (! conn_ctx_key_initialized)
 198                 return NULL;
 199         return pthread_getspecific(conn_ctx_key);
 200 } /* sdb_conn_get_ctx */
 201
 202 /*
 203  * connection handler functions
 204  */
 205
 206 /*
 207  * connection_log:
 208  * Send a log message originating from the current thread to the client.
 209  */
 210 static int
 211 connection_log(int prio, const char *msg,
 212                 sdb_object_t __attribute__((unused)) *user_data)
 213 {
 214         sdb_conn_t *conn;
 215
 216         conn = sdb_conn_get_ctx();
 217         /* no connection associated to this thread
 218          * or user not authenticated yet => don't leak any information */
 219         if ((! conn) || (! conn->username))
 220                 return 0;
 221
 222         /* XXX: make the log-level configurable by the client at runtime */
 223         if (prio >= SDB_LOG_DEBUG)
 224                 return 0;
 225
 226         /* TODO: Use CONNECTION_LOG_<prio>? */
 227         if (sdb_connection_send(conn, CONNECTION_LOG,
 228                                 (uint32_t)strlen(msg), msg) < 0)
 229                 return -1;
 230         return 0;
 231 } /* connection_log */
 232
 233 static uint32_t
 234 connection_get_int32(sdb_conn_t *conn, size_t offset)
 235 {
 236         const char *data;
 237         uint32_t n;
 238
 239         assert(conn && (sdb_strbuf_len(conn->buf) >= offset + sizeof(uint32_t)));
 240
 241         data = sdb_strbuf_string(conn->buf);
 242         memcpy(&n, data + offset, sizeof(n));
 243         n = ntohl(n);
 244         return n;
 245 } /* connection_get_int32 */
 246
 247 static int
 248 command_handle(sdb_conn_t *conn)
 249 {
 250         int status = -1;
 251
 252         assert(conn && (conn->cmd != CONNECTION_IDLE));
 253
 254         sdb_log(SDB_LOG_DEBUG, "frontend: Handling command %u (len: %u)",
 255                         conn->cmd, conn->cmd_len);
 256
 257         if ((! conn->username) && (conn->cmd != CONNECTION_STARTUP)) {
 258                 const char *errmsg = "Authentication required";
 259                 sdb_connection_send(conn, CONNECTION_ERROR,
 260                                 (uint32_t)strlen(errmsg), errmsg);
 261                 return -1;
 262         }
 263
 264         /* reset */
 265         sdb_strbuf_sprintf(conn->errbuf, "");
 266
 267         switch (conn->cmd) {
 268                 case CONNECTION_PING:
 269                         status = sdb_connection_ping(conn);
 270                         break;
 271                 case CONNECTION_STARTUP:
 272                         status = sdb_fe_session_start(conn);
 273                         break;
 274
 275                 case CONNECTION_QUERY:
 276                 {
 277                         sdb_llist_t *parsetree;
 278                         sdb_conn_node_t *node = NULL;
 279
 280                         parsetree = sdb_fe_parse(sdb_strbuf_string(conn->buf),
 281                                         (int)conn->cmd_len);
 282                         if (! parsetree) {
 283                                 sdb_log(SDB_LOG_ERR, "frontend: Failed to parse query '%s'",
 284                                                 sdb_strbuf_string(conn->buf));
 285                                 status = -1;
 286                                 break;
 287                         }
 288
 289                         switch (sdb_llist_len(parsetree)) {
 290                                 case 0:
 291                                         /* skipping empty command */
 292                                         break;
 293                                 case 1:
 294                                         node = SDB_CONN_NODE(sdb_llist_get(parsetree, 0));
 295                                         break;
 296
 297                                 default:
 298                                         sdb_log(SDB_LOG_WARNING, "frontend: Ignoring %d command%s "
 299                                                         "in multi-statement query '%s'",
 300                                                         sdb_llist_len(parsetree) - 1,
 301                                                         sdb_llist_len(parsetree) == 2 ? "" : "s",
 302                                                         sdb_strbuf_string(conn->buf));
 303                                         node = SDB_CONN_NODE(sdb_llist_get(parsetree, 0));
 304                         }
 305
 306                         if (node) {
 307                                 status = sdb_fe_exec(conn, node);
 308                                 sdb_object_deref(SDB_OBJ(node));
 309                         }
 310
 311                         sdb_llist_destroy(parsetree);
 312                         break;
 313                 }
 314
 315                 case CONNECTION_FETCH:
 316                         status = sdb_fe_fetch(conn, sdb_strbuf_string(conn->buf));
 317                         break;
 318                 case CONNECTION_LIST:
 319                         status = sdb_fe_list(conn);
 320                         break;
 321                 case CONNECTION_LOOKUP:
 322                 {
 323                         sdb_store_matcher_t *m;
 324
 325                         m = sdb_fe_parse_matcher(sdb_strbuf_string(conn->buf),
 326                                         (int)conn->cmd_len);
 327                         if (! m) {
 328                                 sdb_log(SDB_LOG_ERR, "frontend: Failed to parse expression '%s'",
 329                                                 sdb_strbuf_string(conn->buf));
 330                                 status = -1;
 331                                 break;
 332                         }
 333
 334                         status = sdb_fe_lookup(conn, m);
 335                         sdb_object_deref(SDB_OBJ(m));
 336                         break;
 337                 }
 338
 339                 default:
 340                 {
 341                         sdb_log(SDB_LOG_WARNING, "frontend: Ignoring invalid command %#x",
 342                                         conn->cmd);
 343                         sdb_strbuf_sprintf(conn->errbuf, "Invalid command %#x", conn->cmd);
 344                         status = -1;
 345                         break;
 346                 }
 347         }
 348
 349         if (status)
 350                 sdb_connection_send(conn, CONNECTION_ERROR,
 351                                 (uint32_t)sdb_strbuf_len(conn->errbuf),
 352                                 sdb_strbuf_string(conn->errbuf));
 353
 354         /* remove the command from the buffer */
 355         if (conn->cmd_len)
 356                 sdb_strbuf_skip(conn->buf, 0, conn->cmd_len);
 357         conn->cmd = CONNECTION_IDLE;
 358         conn->cmd_len = 0;
 359         return status;
 360 } /* command_handle */
 361
 362 /* initialize the connection state information */
 363 static int
 364 command_init(sdb_conn_t *conn)
 365 {
 366         size_t len;
 367
 368         assert(conn && (conn->cmd == CONNECTION_IDLE) && (! conn->cmd_len));
 369
 370         conn->cmd = connection_get_int32(conn, 0);
 371         conn->cmd_len = connection_get_int32(conn, sizeof(uint32_t));
 372
 373         len = 2 * sizeof(uint32_t);
 374         if (conn->cmd == CONNECTION_IDLE)
 375                 len += conn->cmd_len;
 376         sdb_strbuf_skip(conn->buf, 0, len);
 377         return 0;
 378 } /* command_init */
 379
 380 /* returns negative value on error, 0 on EOF, number of octets else */
 381 static ssize_t
 382 connection_read(sdb_conn_t *conn)
 383 {
 384         ssize_t n = 0;
 385
 386         if ((! conn) || (conn->fd < 0))
 387                 return -1;
 388
 389         while (42) {
 390                 ssize_t status;
 391
 392                 errno = 0;
 393                 status = sdb_strbuf_read(conn->buf, conn->fd, 1024);
 394                 if (status < 0) {
 395                         if ((errno == EAGAIN) || (errno == EWOULDBLOCK))
 396                                 break;
 397
 398                         close(conn->fd);
 399                         conn->fd = -1;
 400                         return (int)status;
 401                 }
 402                 else if (! status) /* EOF */
 403                         break;
 404
 405                 n += status;
 406         }
 407
 408         return n;
 409 } /* connection_read */
 410
 411 /*
 412  * public API
 413  */
 414
 415 int
 416 sdb_connection_enable_logging(void)
 417 {
 418         return sdb_plugin_register_log("connection-logger", connection_log,
 419                         /* user_data = */ NULL);
 420 } /* sdb_connection_enable_logging */
 421
 422 sdb_conn_t *
 423 sdb_connection_accept(int fd)
 424 {
 425         if (fd < 0)
 426                 return NULL;
 427
 428         /* the placeholder will be replaced with the accepted file
 429          * descriptor when initializing the object */
 430         return CONN(sdb_object_create(CONN_FD_PREFIX CONN_FD_PLACEHOLDER,
 431                                 connection_type, fd));
 432 } /* sdb_connection_create */
 433
 434 void
 435 sdb_connection_close(sdb_conn_t *conn)
 436 {
 437         sdb_object_deref(SDB_OBJ(conn));
 438 } /* sdb_connection_close */
 439
 440 ssize_t
 441 sdb_connection_read(sdb_conn_t *conn)
 442 {
 443         ssize_t n = 0;
 444
 445         sdb_conn_set_ctx(conn);
 446
 447         while (42) {
 448                 ssize_t status = connection_read(conn);
 449
 450                 if ((conn->cmd == CONNECTION_IDLE) && (! conn->cmd_len)
 451                                 && (sdb_strbuf_len(conn->buf) >= 2 * sizeof(int32_t)))
 452                         command_init(conn);
 453                 if ((conn->cmd != CONNECTION_IDLE)
 454                                 && (sdb_strbuf_len(conn->buf) >= conn->cmd_len))
 455                         command_handle(conn);
 456
 457                 if (status <= 0)
 458                         break;
 459
 460                 n += status;
 461         }
 462
 463         sdb_conn_set_ctx(NULL);
 464         return n;
 465 } /* sdb_connection_read */
 466
 467 ssize_t
 468 sdb_connection_send(sdb_conn_t *conn, uint32_t code,
 469                 uint32_t msg_len, const char *msg)
 470 {
 471         ssize_t status;
 472
 473         if ((! conn) || (conn->fd < 0))
 474                 return -1;
 475
 476         status = sdb_proto_send_msg(conn->fd, code, msg_len, msg);
 477         if (status < 0) {
 478                 char errbuf[1024];
 479
 480                 /* tell other code that there was a problem and, more importantly,
 481                  * make sure we don't try to send further logs to the connection */
 482                 close(conn->fd);
 483                 conn->fd = -1;
 484
 485                 sdb_log(SDB_LOG_ERR, "frontend: Failed to send msg "
 486                                 "(code: %u, len: %u) to client: %s", code, msg_len,
 487                                 sdb_strerror(errno, errbuf, sizeof(errbuf)));
 488         }
 489         return status;
 490 } /* sdb_connection_send */
 491
 492 int
 493 sdb_connection_ping(sdb_conn_t *conn)
 494 {
 495         if ((! conn) || (conn->cmd != CONNECTION_PING))
 496                 return -1;
 497
 498         /* we're alive */
 499         sdb_connection_send(conn, CONNECTION_OK, 0, NULL);
 500         return 0;
 501 } /* sdb_connection_ping */
 502
 503 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */
 504