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         switch (conn->cmd) {
 269                 case CONNECTION_PING:
 270                         status = sdb_connection_ping(conn);
 271                         break;
 272                 case CONNECTION_STARTUP:
 273                         status = sdb_fe_session_start(conn);
 274                         break;
 275
 276                 case CONNECTION_QUERY:
 277                 {
 278                         sdb_llist_t *parsetree;
 279                         sdb_conn_node_t *node = NULL;
 280
 281                         parsetree = sdb_fe_parse(sdb_strbuf_string(conn->buf),
 282                                         (int)conn->cmd_len);
 283                         if (! parsetree) {
 284                                 sdb_log(SDB_LOG_ERR, "frontend: Failed to parse query '%s'",
 285                                                 sdb_strbuf_string(conn->buf));
 286                                 status = -1;
 287                                 break;
 288                         }
 289
 290                         switch (sdb_llist_len(parsetree)) {
 291                                 case 0:
 292                                         /* skipping empty command */
 293                                         break;
 294                                 case 1:
 295                                         node = SDB_CONN_NODE(sdb_llist_get(parsetree, 0));
 296                                         break;
 297
 298                                 default:
 299                                         sdb_log(SDB_LOG_WARNING, "frontend: Ignoring %d command%s "
 300                                                         "in multi-statement query '%s'",
 301                                                         sdb_llist_len(parsetree) - 1,
 302                                                         sdb_llist_len(parsetree) == 2 ? "" : "s",
 303                                                         sdb_strbuf_string(conn->buf));
 304                                         node = SDB_CONN_NODE(sdb_llist_get(parsetree, 0));
 305                         }
 306
 307                         if (node) {
 308                                 status = sdb_fe_exec(conn, node);
 309                                 sdb_object_deref(SDB_OBJ(node));
 310                         }
 311
 312                         sdb_llist_destroy(parsetree);
 313                         break;
 314                 }
 315
 316                 case CONNECTION_FETCH:
 317                         status = sdb_fe_fetch(conn, sdb_strbuf_string(conn->buf));
 318                         break;
 319                 case CONNECTION_LIST:
 320                         status = sdb_fe_list(conn);
 321                         break;
 322                 case CONNECTION_LOOKUP:
 323                 {
 324                         sdb_store_matcher_t *m;
 325
 326                         m = sdb_fe_parse_matcher(sdb_strbuf_string(conn->buf),
 327                                         (int)conn->cmd_len);
 328                         if (! m) {
 329                                 sdb_log(SDB_LOG_ERR, "frontend: Failed to parse expression '%s'",
 330                                                 sdb_strbuf_string(conn->buf));
 331                                 status = -1;
 332                                 break;
 333                         }
 334
 335                         status = sdb_fe_lookup(conn, m);
 336                         sdb_object_deref(SDB_OBJ(m));
 337                         break;
 338                 }
 339
 340                 default:
 341                 {
 342                         sdb_log(SDB_LOG_WARNING, "frontend: Ignoring invalid command %#x",
 343                                         conn->cmd);
 344                         sdb_strbuf_sprintf(conn->errbuf, "Invalid command %#x", conn->cmd);
 345                         status = -1;
 346                         break;
 347                 }
 348         }
 349
 350         if (status)
 351                 sdb_connection_send(conn, CONNECTION_ERROR,
 352                                 (uint32_t)sdb_strbuf_len(conn->errbuf),
 353                                 sdb_strbuf_string(conn->errbuf));
 354         return status;
 355 } /* command_handle */
 356
 357 /* initialize the connection state information */
 358 static int
 359 command_init(sdb_conn_t *conn)
 360 {
 361         const char *errmsg = NULL;
 362
 363         assert(conn && (conn->cmd == CONNECTION_IDLE) && (! conn->cmd_len));
 364
 365         if (conn->skip_len)
 366                 return -1;
 367
 368         /* reset */
 369         sdb_strbuf_sprintf(conn->errbuf, "");
 370
 371         conn->cmd = connection_get_int32(conn, 0);
 372         conn->cmd_len = connection_get_int32(conn, sizeof(uint32_t));
 373
 374         sdb_strbuf_skip(conn->buf, 0, 2 * sizeof(uint32_t));
 375
 376         if ((! conn->username) && (conn->cmd != CONNECTION_STARTUP))
 377                 errmsg = "Authentication required";
 378         else if (conn->cmd == CONNECTION_IDLE)
 379                 errmsg = "Invalid command 0";
 380
 381         if (errmsg) {
 382                 size_t len = sdb_strbuf_len(conn->buf);
 383
 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 = CONNECTION_IDLE;
 389                 conn->cmd_len = 0;
 390
 391                 if (len > conn->skip_len)
 392                         len = conn->skip_len;
 393                 sdb_strbuf_skip(conn->buf, 0, len);
 394                 conn->skip_len -= len;
 395                 /* connection_read will handle anything else */
 396         }
 397         return 0;
 398 } /* command_init */
 399
 400 /* returns negative value on error, 0 on EOF, number of octets else */
 401 static ssize_t
 402 connection_read(sdb_conn_t *conn)
 403 {
 404         ssize_t n = 0;
 405
 406         if ((! conn) || (conn->fd < 0))
 407                 return -1;
 408
 409         while (42) {
 410                 ssize_t status;
 411
 412                 errno = 0;
 413                 status = sdb_strbuf_read(conn->buf, conn->fd, 1024);
 414                 if (status < 0) {
 415                         if ((errno == EAGAIN) || (errno == EWOULDBLOCK))
 416                                 break;
 417
 418                         close(conn->fd);
 419                         conn->fd = -1;
 420                         return (int)status;
 421                 }
 422                 else if (! status) /* EOF */
 423                         break;
 424
 425                 if (conn->skip_len) {
 426                         size_t len = (size_t)status < conn->skip_len
 427                                 ? (size_t)status : conn->skip_len;
 428                         sdb_strbuf_skip(conn->buf, 0, len);
 429                         conn->skip_len -= len;
 430                 }
 431
 432                 n += status;
 433
 434                 /* give the main loop a chance to execute commands (and free up buffer
 435                  * space) on large amounts of incoming traffic */
 436                 if (n > 1024 * 1024)
 437                         break;
 438         }
 439
 440         return n;
 441 } /* connection_read */
 442
 443 /*
 444  * public API
 445  */
 446
 447 int
 448 sdb_connection_enable_logging(void)
 449 {
 450         return sdb_plugin_register_log("connection-logger", connection_log,
 451                         /* user_data = */ NULL);
 452 } /* sdb_connection_enable_logging */
 453
 454 sdb_conn_t *
 455 sdb_connection_accept(int fd)
 456 {
 457         if (fd < 0)
 458                 return NULL;
 459
 460         /* the placeholder will be replaced with the accepted file
 461          * descriptor when initializing the object */
 462         return CONN(sdb_object_create(CONN_FD_PREFIX CONN_FD_PLACEHOLDER,
 463                                 connection_type, fd));
 464 } /* sdb_connection_create */
 465
 466 void
 467 sdb_connection_close(sdb_conn_t *conn)
 468 {
 469         if (! conn)
 470                 return;
 471
 472         /* close the connection even if someone else still references it */
 473         if (conn->fd >= 0)
 474                 close(conn->fd);
 475         conn->fd = -1;
 476
 477         sdb_object_deref(SDB_OBJ(conn));
 478 } /* sdb_connection_close */
 479
 480 ssize_t
 481 sdb_connection_read(sdb_conn_t *conn)
 482 {
 483         ssize_t n = 0;
 484
 485         sdb_conn_set_ctx(conn);
 486
 487         while (42) {
 488                 ssize_t status = connection_read(conn);
 489
 490                 if ((conn->cmd == CONNECTION_IDLE) && (! conn->cmd_len)
 491                                 && (sdb_strbuf_len(conn->buf) >= 2 * sizeof(int32_t)))
 492                         command_init(conn);
 493                 if ((conn->cmd != CONNECTION_IDLE)
 494                                 && (sdb_strbuf_len(conn->buf) >= conn->cmd_len)) {
 495                         command_handle(conn);
 496
 497                         /* remove the command from the buffer */
 498                         if (conn->cmd_len)
 499                                 sdb_strbuf_skip(conn->buf, 0, conn->cmd_len);
 500                         conn->cmd = CONNECTION_IDLE;
 501                         conn->cmd_len = 0;
 502                 }
 503
 504                 if (status <= 0)
 505                         break;
 506
 507                 n += status;
 508         }
 509
 510         sdb_conn_set_ctx(NULL);
 511         return n;
 512 } /* sdb_connection_read */
 513
 514 ssize_t
 515 sdb_connection_send(sdb_conn_t *conn, uint32_t code,
 516                 uint32_t msg_len, const char *msg)
 517 {
 518         ssize_t status;
 519
 520         if ((! conn) || (conn->fd < 0))
 521                 return -1;
 522
 523         status = sdb_proto_send_msg(conn->fd, code, msg_len, msg);
 524         if (status < 0) {
 525                 char errbuf[1024];
 526
 527                 /* tell other code that there was a problem and, more importantly,
 528                  * make sure we don't try to send further logs to the connection */
 529                 close(conn->fd);
 530                 conn->fd = -1;
 531
 532                 sdb_log(SDB_LOG_ERR, "frontend: Failed to send msg "
 533                                 "(code: %u, len: %u) to client: %s", code, msg_len,
 534                                 sdb_strerror(errno, errbuf, sizeof(errbuf)));
 535         }
 536         return status;
 537 } /* sdb_connection_send */
 538
 539 int
 540 sdb_connection_ping(sdb_conn_t *conn)
 541 {
 542         if ((! conn) || (conn->cmd != CONNECTION_PING))
 543                 return -1;
 544
 545         /* we're alive */
 546         sdb_connection_send(conn, CONNECTION_OK, 0, NULL);
 547         return 0;
 548 } /* sdb_connection_ping */
 549
 550 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */
 551