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