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 "utils/error.h"
  33 #include "utils/strbuf.h"
  34 #include "utils/proto.h"
  35
  36 #include <assert.h>
  37 #include <errno.h>
  38
  39 #include <arpa/inet.h>
  40 #include <fcntl.h>
  41
  42 #include <stdlib.h>
  43 #include <string.h>
  44
  45 #include <pthread.h>
  46
  47 /*
  48  * private variables
  49  */
  50
  51 static pthread_key_t conn_ctx_key;
  52 static _Bool         conn_ctx_key_initialized = 0;
  53
  54 /*
  55  * private types
  56  */
  57
  58 /* name of connection objects */
  59 #define CONN_FD_PREFIX "conn#"
  60 #define CONN_FD_PLACEHOLDER "XXXXXXX"
  61
  62 static int
  63 connection_init(sdb_object_t *obj, va_list ap)
  64 {
  65         sdb_conn_t *conn;
  66         int sock_fd;
  67         int sock_fl;
  68
  69         assert(obj);
  70         conn = CONN(obj);
  71
  72         sock_fd = va_arg(ap, int);
  73
  74         conn->buf = sdb_strbuf_create(/* size = */ 128);
  75         if (! conn->buf) {
  76                 sdb_log(SDB_LOG_ERR, "frontend: Failed to allocate a read buffer "
  77                                 "for a new connection");
  78                 return -1;
  79         }
  80         conn->errbuf = sdb_strbuf_create(0);
  81         if (! conn->errbuf) {
  82                 sdb_log(SDB_LOG_ERR, "frontend: Failed to allocate an error buffer "
  83                                 "for a new connection");
  84                 return -1;
  85         }
  86
  87         conn->client_addr_len = sizeof(conn->client_addr);
  88         conn->fd = accept(sock_fd, (struct sockaddr *)&conn->client_addr,
  89                         &conn->client_addr_len);
  90
  91         if (conn->fd < 0) {
  92                 char buf[1024];
  93                 sdb_log(SDB_LOG_ERR, "frontend: Failed to accept remote "
  94                                 "connection: %s", sdb_strerror(errno,
  95                                         buf, sizeof(buf)));
  96                 return -1;
  97         }
  98
  99         if (conn->client_addr.ss_family != AF_UNIX) {
 100                 sdb_log(SDB_LOG_ERR, "frontend: Accepted connection using "
 101                                 "unexpected family type %d", conn->client_addr.ss_family);
 102                 return -1;
 103         }
 104
 105         sock_fl = fcntl(conn->fd, F_GETFL);
 106         if (fcntl(conn->fd, F_SETFL, sock_fl | O_NONBLOCK)) {
 107                 char buf[1024];
 108                 sdb_log(SDB_LOG_ERR, "frontend: Failed to switch connection conn#%i "
 109                                 "to non-blocking mode: %s", conn->fd,
 110                                 sdb_strerror(errno, buf, sizeof(buf)));
 111                 return -1;
 112         }
 113
 114         sdb_log(SDB_LOG_DEBUG, "frontend: Accepted connection on fd=%i",
 115                         conn->fd);
 116
 117         conn->cmd = SDB_CONNECTION_IDLE;
 118         conn->cmd_len = 0;
 119         conn->skip_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         conn->ready = 0;
 137
 138         if (conn->buf) {
 139                 len = sdb_strbuf_len(conn->buf);
 140                 if (len)
 141                         sdb_log(SDB_LOG_INFO, "frontend: Discarding incomplete command "
 142                                         "(%zu byte%s left in buffer)", len, len == 1 ? "" : "s");
 143         }
 144
 145         sdb_log(SDB_LOG_DEBUG, "frontend: Closing connection %s", obj->name);
 146         if (conn->fd >= 0)
 147                 close(conn->fd);
 148         conn->fd = -1;
 149
 150         if (conn->username)
 151                 free(conn->username);
 152         conn->username = NULL;
 153
 154         sdb_strbuf_destroy(conn->buf);
 155         conn->buf = NULL;
 156         sdb_strbuf_destroy(conn->errbuf);
 157         conn->errbuf = NULL;
 158 } /* connection_destroy */
 159
 160 static sdb_type_t connection_type = {
 161         /* size = */ sizeof(sdb_conn_t),
 162         /* init = */ connection_init,
 163         /* destroy = */ connection_destroy,
 164 };
 165
 166 /*
 167  * private helper functions
 168  */
 169
 170 static void
 171 sdb_conn_ctx_destructor(void *c)
 172 {
 173         sdb_object_t *conn = c;
 174
 175         if (! conn)
 176                 return;
 177         sdb_object_deref(conn);
 178 } /* sdb_conn_ctx_destructor */
 179
 180 static void
 181 sdb_conn_ctx_init(void)
 182 {
 183         if (conn_ctx_key_initialized)
 184                 return;
 185
 186         pthread_key_create(&conn_ctx_key, sdb_conn_ctx_destructor);
 187         conn_ctx_key_initialized = 1;
 188 } /* sdb_conn_ctx_init */
 189
 190 static void
 191 sdb_conn_set_ctx(sdb_conn_t *conn)
 192 {
 193         sdb_conn_t *old;
 194
 195         sdb_conn_ctx_init();
 196
 197         old = pthread_getspecific(conn_ctx_key);
 198         if (old)
 199                 sdb_object_deref(SDB_OBJ(old));
 200         if (conn)
 201                 sdb_object_ref(SDB_OBJ(conn));
 202         pthread_setspecific(conn_ctx_key, conn);
 203 } /* sdb_conn_set_ctx */
 204
 205 static sdb_conn_t *
 206 sdb_conn_get_ctx(void)
 207 {
 208         if (! conn_ctx_key_initialized)
 209                 return NULL;
 210         return pthread_getspecific(conn_ctx_key);
 211 } /* sdb_conn_get_ctx */
 212
 213 /*
 214  * connection handler functions
 215  */
 216
 217 /*
 218  * connection_log:
 219  * Send a log message originating from the current thread to the client.
 220  */
 221 static int
 222 connection_log(int prio, const char *msg,
 223                 sdb_object_t __attribute__((unused)) *user_data)
 224 {
 225         uint32_t len = (uint32_t)sizeof(uint32_t) + (uint32_t)strlen(msg);
 226         uint32_t p = htonl((uint32_t)prio);
 227         char tmp[len + 1];
 228
 229         sdb_conn_t *conn;
 230
 231         conn = sdb_conn_get_ctx();
 232         /* no connection associated to this thread
 233          * or startup not done yet => don't leak any information */
 234         if ((! conn) || (! conn->ready))
 235                 return 0;
 236
 237         /* XXX: make the log-level configurable by the client at runtime */
 238         if (prio >= SDB_LOG_DEBUG)
 239                 return 0;
 240
 241         memcpy(tmp, &p, sizeof(p));
 242         strcpy(tmp + sizeof(p), msg);
 243
 244         if (sdb_connection_send(conn, SDB_CONNECTION_LOG, len, tmp) < 0)
 245                 return -1;
 246         return 0;
 247 } /* connection_log */
 248
 249 static int
 250 command_handle(sdb_conn_t *conn)
 251 {
 252         int status = -1;
 253
 254         assert(conn && (conn->cmd != SDB_CONNECTION_IDLE));
 255         assert(! conn->skip_len);
 256
 257         sdb_log(SDB_LOG_DEBUG, "frontend: Handling command %u (len: %u)",
 258                         conn->cmd, conn->cmd_len);
 259
 260         if (conn->cmd == SDB_CONNECTION_PING)
 261                 status = sdb_connection_ping(conn);
 262         else if (conn->cmd == SDB_CONNECTION_STARTUP)
 263                 status = sdb_fe_session_start(conn);
 264         else if (conn->cmd == SDB_CONNECTION_QUERY)
 265                 status = sdb_fe_query(conn);
 266         else if (conn->cmd == SDB_CONNECTION_FETCH)
 267                 status = sdb_fe_fetch(conn);
 268         else if (conn->cmd == SDB_CONNECTION_LIST)
 269                 status = sdb_fe_list(conn);
 270         else if (conn->cmd == SDB_CONNECTION_LOOKUP)
 271                 status = sdb_fe_lookup(conn);
 272         else {
 273                 sdb_log(SDB_LOG_WARNING, "frontend: Ignoring invalid command %#x",
 274                                 conn->cmd);
 275                 sdb_strbuf_sprintf(conn->errbuf, "Invalid command %#x", conn->cmd);
 276                 status = -1;
 277         }
 278
 279         if (status) {
 280                 if (! sdb_strbuf_len(conn->errbuf))
 281                         sdb_strbuf_sprintf(conn->errbuf, "Failed to execute command");
 282                 sdb_connection_send(conn, SDB_CONNECTION_ERROR,
 283                                 (uint32_t)sdb_strbuf_len(conn->errbuf),
 284                                 sdb_strbuf_string(conn->errbuf));
 285         }
 286         return status;
 287 } /* command_handle */
 288
 289 /* initialize the connection state information */
 290 static int
 291 command_init(sdb_conn_t *conn)
 292 {
 293         const char *errmsg = NULL;
 294
 295         assert(conn && (conn->cmd == SDB_CONNECTION_IDLE) && (! conn->cmd_len));
 296
 297         if (conn->skip_len)
 298                 return -1;
 299
 300         /* reset */
 301         sdb_strbuf_clear(conn->errbuf);
 302
 303         conn->cmd = sdb_proto_get_int(conn->buf, 0);
 304         conn->cmd_len = sdb_proto_get_int(conn->buf, sizeof(uint32_t));
 305
 306         sdb_strbuf_skip(conn->buf, 0, 2 * sizeof(uint32_t));
 307
 308         if ((! conn->ready) && (conn->cmd != SDB_CONNECTION_STARTUP))
 309                 errmsg = "Authentication required";
 310         else if (conn->cmd == SDB_CONNECTION_IDLE)
 311                 errmsg = "Invalid command 0";
 312
 313         if (errmsg) {
 314                 size_t len = sdb_strbuf_len(conn->buf);
 315
 316                 sdb_strbuf_sprintf(conn->errbuf, "%s", errmsg);
 317                 sdb_connection_send(conn, SDB_CONNECTION_ERROR,
 318                                 (uint32_t)strlen(errmsg), errmsg);
 319                 conn->skip_len += conn->cmd_len;
 320                 conn->cmd = SDB_CONNECTION_IDLE;
 321                 conn->cmd_len = 0;
 322
 323                 if (len > conn->skip_len)
 324                         len = conn->skip_len;
 325                 sdb_strbuf_skip(conn->buf, 0, len);
 326                 conn->skip_len -= len;
 327                 /* connection_read will handle anything else */
 328         }
 329         return 0;
 330 } /* command_init */
 331
 332 /* returns negative value on error, 0 on EOF, number of octets else */
 333 static ssize_t
 334 connection_read(sdb_conn_t *conn)
 335 {
 336         ssize_t n = 0;
 337
 338         if ((! conn) || (conn->fd < 0))
 339                 return -1;
 340
 341         while (42) {
 342                 ssize_t status;
 343
 344                 errno = 0;
 345                 status = sdb_strbuf_read(conn->buf, conn->fd, 1024);
 346                 if (status < 0) {
 347                         if ((errno == EAGAIN) || (errno == EWOULDBLOCK))
 348                                 break;
 349
 350                         close(conn->fd);
 351                         conn->fd = -1;
 352                         return (int)status;
 353                 }
 354                 else if (! status) /* EOF */
 355                         break;
 356
 357                 if (conn->skip_len) {
 358                         size_t len = (size_t)status < conn->skip_len
 359                                 ? (size_t)status : conn->skip_len;
 360                         sdb_strbuf_skip(conn->buf, 0, len);
 361                         conn->skip_len -= len;
 362                 }
 363
 364                 n += status;
 365
 366                 /* give the main loop a chance to execute commands (and free up buffer
 367                  * space) on large amounts of incoming traffic */
 368                 if (n > 1024 * 1024)
 369                         break;
 370         }
 371
 372         return n;
 373 } /* connection_read */
 374
 375 /*
 376  * public API
 377  */
 378
 379 int
 380 sdb_connection_enable_logging(void)
 381 {
 382         return sdb_plugin_register_log("connection-logger", connection_log,
 383                         /* user_data = */ NULL);
 384 } /* sdb_connection_enable_logging */
 385
 386 sdb_conn_t *
 387 sdb_connection_accept(int fd)
 388 {
 389         if (fd < 0)
 390                 return NULL;
 391
 392         /* the placeholder will be replaced with the accepted file
 393          * descriptor when initializing the object */
 394         return CONN(sdb_object_create(CONN_FD_PREFIX CONN_FD_PLACEHOLDER,
 395                                 connection_type, fd));
 396 } /* sdb_connection_create */
 397
 398 void
 399 sdb_connection_close(sdb_conn_t *conn)
 400 {
 401         if (! conn)
 402                 return;
 403
 404         /* close the connection even if someone else still references it */
 405         if (conn->fd >= 0)
 406                 close(conn->fd);
 407         conn->fd = -1;
 408
 409         sdb_object_deref(SDB_OBJ(conn));
 410 } /* sdb_connection_close */
 411
 412 ssize_t
 413 sdb_connection_read(sdb_conn_t *conn)
 414 {
 415         ssize_t n = 0;
 416
 417         sdb_conn_set_ctx(conn);
 418
 419         while (42) {
 420                 ssize_t status = connection_read(conn);
 421
 422                 if ((conn->cmd == SDB_CONNECTION_IDLE) && (! conn->cmd_len)
 423                                 && (sdb_strbuf_len(conn->buf) >= 2 * sizeof(int32_t)))
 424                         command_init(conn);
 425                 if ((conn->cmd != SDB_CONNECTION_IDLE)
 426                                 && (sdb_strbuf_len(conn->buf) >= conn->cmd_len)) {
 427                         command_handle(conn);
 428
 429                         /* remove the command from the buffer */
 430                         if (conn->cmd_len)
 431                                 sdb_strbuf_skip(conn->buf, 0, conn->cmd_len);
 432                         conn->cmd = SDB_CONNECTION_IDLE;
 433                         conn->cmd_len = 0;
 434                 }
 435
 436                 if (status <= 0)
 437                         break;
 438
 439                 n += status;
 440         }
 441
 442         sdb_conn_set_ctx(NULL);
 443         return n;
 444 } /* sdb_connection_read */
 445
 446 ssize_t
 447 sdb_connection_send(sdb_conn_t *conn, uint32_t code,
 448                 uint32_t msg_len, const char *msg)
 449 {
 450         ssize_t status;
 451
 452         if ((! conn) || (conn->fd < 0))
 453                 return -1;
 454
 455         status = sdb_proto_send_msg(conn->fd, code, msg_len, msg);
 456         if (status < 0) {
 457                 char errbuf[1024];
 458
 459                 /* tell other code that there was a problem and, more importantly,
 460                  * make sure we don't try to send further logs to the connection */
 461                 close(conn->fd);
 462                 conn->fd = -1;
 463                 conn->ready = 0;
 464
 465                 sdb_log(SDB_LOG_ERR, "frontend: Failed to send msg "
 466                                 "(code: %u, len: %u) to client: %s", code, msg_len,
 467                                 sdb_strerror(errno, errbuf, sizeof(errbuf)));
 468         }
 469         return status;
 470 } /* sdb_connection_send */
 471
 472 int
 473 sdb_connection_ping(sdb_conn_t *conn)
 474 {
 475         if ((! conn) || (conn->cmd != SDB_CONNECTION_PING))
 476                 return -1;
 477
 478         /* we're alive */
 479         sdb_connection_send(conn, SDB_CONNECTION_OK, 0, NULL);
 480         return 0;
 481 } /* sdb_connection_ping */
 482
 483 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */
 484