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 = CONNECTION_IDLE;
 118         conn->cmd_len = 0;
 119
 120         /* update the object name */
 121         snprintf(obj->name + strlen(CONN_FD_PREFIX),
 122                         strlen(CONN_FD_PLACEHOLDER), "%i", conn->fd);
 123         return 0;
 124 } /* connection_init */
 125
 126 static void
 127 connection_destroy(sdb_object_t *obj)
 128 {
 129         sdb_conn_t *conn;
 130         size_t len;
 131
 132         assert(obj);
 133         conn = CONN(obj);
 134
 135         if (conn->buf) {
 136                 len = sdb_strbuf_len(conn->buf);
 137                 if (len)
 138                         sdb_log(SDB_LOG_INFO, "frontend: Discarding incomplete command "
 139                                         "(%zu byte%s left in buffer)", len, len == 1 ? "" : "s");
 140         }
 141
 142         sdb_log(SDB_LOG_DEBUG, "frontend: Closing connection on fd=%i",
 143                         conn->fd);
 144         close(conn->fd);
 145         conn->fd = -1;
 146
 147         sdb_strbuf_destroy(conn->buf);
 148         conn->buf = NULL;
 149         sdb_strbuf_destroy(conn->errbuf);
 150         conn->errbuf = NULL;
 151 } /* connection_destroy */
 152
 153 static sdb_type_t connection_type = {
 154         /* size = */ sizeof(sdb_conn_t),
 155         /* init = */ connection_init,
 156         /* destroy = */ connection_destroy,
 157 };
 158
 159 /*
 160  * private helper functions
 161  */
 162
 163 static void
 164 sdb_conn_ctx_destructor(void *c)
 165 {
 166         sdb_object_t *conn = c;
 167
 168         if (! conn)
 169                 return;
 170         sdb_object_deref(conn);
 171 } /* sdb_conn_ctx_destructor */
 172
 173 static void
 174 sdb_conn_ctx_init(void)
 175 {
 176         if (conn_ctx_key_initialized)
 177                 return;
 178
 179         pthread_key_create(&conn_ctx_key, sdb_conn_ctx_destructor);
 180         conn_ctx_key_initialized = 1;
 181 } /* sdb_conn_ctx_init */
 182
 183 static void
 184 sdb_conn_set_ctx(sdb_conn_t *conn)
 185 {
 186         sdb_conn_ctx_init();
 187         if (conn)
 188                 sdb_object_ref(SDB_OBJ(conn));
 189         pthread_setspecific(conn_ctx_key, conn);
 190 } /* sdb_conn_set_ctx */
 191
 192 static sdb_conn_t *
 193 sdb_conn_get_ctx(void)
 194 {
 195         if (! conn_ctx_key_initialized)
 196                 return NULL;
 197         return pthread_getspecific(conn_ctx_key);
 198 } /* sdb_conn_get_ctx */
 199
 200 /*
 201  * connection handler functions
 202  */
 203
 204 /*
 205  * connection_log:
 206  * Send a log message originating from the current thread to the client.
 207  */
 208 static int
 209 connection_log(int __attribute__((unused)) prio, const char *msg,
 210                 sdb_object_t __attribute__((unused)) *user_data)
 211 {
 212         sdb_conn_t *conn;
 213
 214         conn = sdb_conn_get_ctx();
 215         /* no connection associated to this thread
 216          * or user not authenticated yet => don't leak any information */
 217         if ((! conn) || (! conn->username))
 218                 return 0;
 219
 220         /* TODO: Use CONNECTION_LOG_<prio>? */
 221         if (sdb_connection_send(conn, CONNECTION_LOG,
 222                                 (uint32_t)strlen(msg), msg) < 0)
 223                 return -1;
 224         return 0;
 225 } /* connection_log */
 226
 227 static uint32_t
 228 connection_get_int32(sdb_conn_t *conn, size_t offset)
 229 {
 230         const char *data;
 231         uint32_t n;
 232
 233         assert(conn && (sdb_strbuf_len(conn->buf) >= offset + sizeof(uint32_t)));
 234
 235         data = sdb_strbuf_string(conn->buf);
 236         memcpy(&n, data + offset, sizeof(n));
 237         n = ntohl(n);
 238         return n;
 239 } /* connection_get_int32 */
 240
 241 static int
 242 command_handle(sdb_conn_t *conn)
 243 {
 244         int status = -1;
 245
 246         assert(conn && (conn->cmd != CONNECTION_IDLE));
 247
 248         sdb_log(SDB_LOG_DEBUG, "frontend: Handling command %u (len: %u)",
 249                         conn->cmd, conn->cmd_len);
 250
 251         if ((! conn->username) && (conn->cmd != CONNECTION_STARTUP)) {
 252                 const char *errmsg = "Authentication required";
 253                 sdb_connection_send(conn, CONNECTION_ERROR,
 254                                 (uint32_t)strlen(errmsg), errmsg);
 255                 return -1;
 256         }
 257
 258         /* reset */
 259         sdb_strbuf_sprintf(conn->errbuf, "");
 260
 261         switch (conn->cmd) {
 262                 case CONNECTION_PING:
 263                         status = sdb_connection_ping(conn);
 264                         break;
 265                 case CONNECTION_STARTUP:
 266                         status = sdb_fe_session_start(conn);
 267                         break;
 268
 269                 case CONNECTION_QUERY:
 270                 {
 271                         sdb_llist_t *parsetree;
 272                         sdb_conn_node_t *node = NULL;
 273
 274                         parsetree = sdb_fe_parse(sdb_strbuf_string(conn->buf),
 275                                         (int)conn->cmd_len);
 276                         if (! parsetree) {
 277                                 sdb_log(SDB_LOG_ERR, "frontend: Failed to parse query '%s'",
 278                                                 sdb_strbuf_string(conn->buf));
 279                                 status = -1;
 280                                 break;
 281                         }
 282
 283                         switch (sdb_llist_len(parsetree)) {
 284                                 case 0:
 285                                         /* skipping empty command */
 286                                         break;
 287                                 case 1:
 288                                         node = SDB_CONN_NODE(sdb_llist_get(parsetree, 0));
 289                                         break;
 290
 291                                 default:
 292                                         sdb_log(SDB_LOG_WARNING, "frontend: Ignoring %d command%s "
 293                                                         "in multi-statement query '%s'",
 294                                                         sdb_llist_len(parsetree) - 1,
 295                                                         sdb_llist_len(parsetree) == 2 ? "" : "s",
 296                                                         sdb_strbuf_string(conn->buf));
 297                                         node = SDB_CONN_NODE(sdb_llist_get(parsetree, 0));
 298                         }
 299
 300                         if (node)
 301                                 status = sdb_fe_exec(conn, node);
 302
 303                         sdb_llist_destroy(parsetree);
 304                         break;
 305                 }
 306
 307                 case CONNECTION_LIST:
 308                         status = sdb_fe_list(conn);
 309                         break;
 310
 311                 default:
 312                 {
 313                         sdb_log(SDB_LOG_WARNING, "frontend: Ignoring invalid command %#x",
 314                                         conn->cmd);
 315                         sdb_strbuf_sprintf(conn->errbuf, "Invalid command %#x", conn->cmd);
 316                         status = -1;
 317                         break;
 318                 }
 319         }
 320
 321         if (status)
 322                 sdb_connection_send(conn, CONNECTION_ERROR,
 323                                 (uint32_t)sdb_strbuf_len(conn->errbuf),
 324                                 sdb_strbuf_string(conn->errbuf));
 325
 326         /* remove the command from the buffer */
 327         if (conn->cmd_len)
 328                 sdb_strbuf_skip(conn->buf, 0, conn->cmd_len);
 329         conn->cmd = CONNECTION_IDLE;
 330         conn->cmd_len = 0;
 331         return status;
 332 } /* command_handle */
 333
 334 /* initialize the connection state information */
 335 static int
 336 command_init(sdb_conn_t *conn)
 337 {
 338         size_t len;
 339
 340         assert(conn && (conn->cmd == CONNECTION_IDLE) && (! conn->cmd_len));
 341
 342         conn->cmd = connection_get_int32(conn, 0);
 343         conn->cmd_len = connection_get_int32(conn, sizeof(uint32_t));
 344
 345         len = 2 * sizeof(uint32_t);
 346         if (conn->cmd == CONNECTION_IDLE)
 347                 len += conn->cmd_len;
 348         sdb_strbuf_skip(conn->buf, 0, len);
 349         return 0;
 350 } /* command_init */
 351
 352 /* returns negative value on error, 0 on EOF, number of octets else */
 353 static ssize_t
 354 connection_read(sdb_conn_t *conn)
 355 {
 356         ssize_t n = 0;
 357
 358         while (42) {
 359                 ssize_t status;
 360
 361                 errno = 0;
 362                 status = sdb_strbuf_read(conn->buf, conn->fd, 1024);
 363                 if (status < 0) {
 364                         if ((errno == EAGAIN) || (errno == EWOULDBLOCK))
 365                                 break;
 366                         return (int)status;
 367                 }
 368                 else if (! status) /* EOF */
 369                         break;
 370
 371                 n += status;
 372         }
 373
 374         return n;
 375 } /* connection_read */
 376
 377 /*
 378  * public API
 379  */
 380
 381 int
 382 sdb_connection_enable_logging(void)
 383 {
 384         return sdb_plugin_register_log("connection-logger", connection_log,
 385                         /* user_data = */ NULL);
 386 } /* sdb_connection_enable_logging */
 387
 388 sdb_conn_t *
 389 sdb_connection_accept(int fd)
 390 {
 391         if (fd < 0)
 392                 return NULL;
 393
 394         /* the placeholder will be replaced with the accepted file
 395          * descriptor when initializing the object */
 396         return CONN(sdb_object_create(CONN_FD_PREFIX CONN_FD_PLACEHOLDER,
 397                                 connection_type, fd));
 398 } /* sdb_connection_create */
 399
 400 void
 401 sdb_connection_close(sdb_conn_t *conn)
 402 {
 403         sdb_object_deref(SDB_OBJ(conn));
 404 } /* sdb_connection_close */
 405
 406 ssize_t
 407 sdb_connection_read(sdb_conn_t *conn)
 408 {
 409         ssize_t n = 0;
 410
 411         sdb_conn_set_ctx(conn);
 412
 413         while (42) {
 414                 ssize_t status = connection_read(conn);
 415
 416                 if ((conn->cmd == CONNECTION_IDLE) && (! conn->cmd_len)
 417                                 && (sdb_strbuf_len(conn->buf) >= 2 * sizeof(int32_t)))
 418                         command_init(conn);
 419                 if ((conn->cmd != CONNECTION_IDLE)
 420                                 && (sdb_strbuf_len(conn->buf) >= conn->cmd_len))
 421                         command_handle(conn);
 422
 423                 if (status <= 0)
 424                         break;
 425
 426                 n += status;
 427         }
 428
 429         sdb_conn_set_ctx(NULL);
 430         return n;
 431 } /* sdb_connection_read */
 432
 433 ssize_t
 434 sdb_connection_send(sdb_conn_t *conn, uint32_t code,
 435                 uint32_t msg_len, const char *msg)
 436 {
 437         ssize_t status;
 438
 439         if ((! conn) || (conn->fd < 0))
 440                 return -1;
 441
 442         status = sdb_proto_send_msg(conn->fd, code, msg_len, msg);
 443         if (status < 0) {
 444                 char errbuf[1024];
 445
 446                 sdb_log(SDB_LOG_ERR, "frontend: Failed to send msg "
 447                                 "(code: %u, len: %u) to client: %s", code, msg_len,
 448                                 sdb_strerror(errno, errbuf, sizeof(errbuf)));
 449         }
 450         return status;
 451 } /* sdb_connection_send */
 452
 453 int
 454 sdb_connection_ping(sdb_conn_t *conn)
 455 {
 456         if ((! conn) || (conn->cmd != CONNECTION_PING))
 457                 return -1;
 458
 459         /* we're alive */
 460         sdb_connection_send(conn, CONNECTION_OK, 0, NULL);
 461         return 0;
 462 } /* sdb_connection_ping */
 463
 464 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */
 465