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 "frontend/connection-private.h"
  31 #include "utils/error.h"
  32 #include "utils/strbuf.h"
  33 #include "utils/proto.h"
  34
  35 #include <assert.h>
  36 #include <errno.h>
  37
  38 #include <arpa/inet.h>
  39 #include <fcntl.h>
  40
  41 #include <string.h>
  42
  43 /*
  44  * private data types
  45  */
  46
  47 /* name of connection objects */
  48 #define CONN_FD_PREFIX "conn#"
  49 #define CONN_FD_PLACEHOLDER "XXXXXXX"
  50
  51 static int
  52 connection_init(sdb_object_t *obj, va_list ap)
  53 {
  54         sdb_conn_t *conn;
  55         int sock_fd;
  56         int sock_fl;
  57
  58         assert(obj);
  59         conn = CONN(obj);
  60
  61         sock_fd = va_arg(ap, int);
  62
  63         conn->buf = sdb_strbuf_create(/* size = */ 128);
  64         if (! conn->buf) {
  65                 sdb_log(SDB_LOG_ERR, "frontend: Failed to allocate a read buffer "
  66                                 "for a new connection");
  67                 return -1;
  68         }
  69         conn->errbuf = sdb_strbuf_create(0);
  70         if (! conn->errbuf) {
  71                 sdb_log(SDB_LOG_ERR, "frontend: Failed to allocate an error buffer "
  72                                 "for a new connection");
  73                 return -1;
  74         }
  75
  76         conn->client_addr_len = sizeof(conn->client_addr);
  77         conn->fd = accept(sock_fd, (struct sockaddr *)&conn->client_addr,
  78                         &conn->client_addr_len);
  79
  80         if (conn->fd < 0) {
  81                 char buf[1024];
  82                 sdb_log(SDB_LOG_ERR, "frontend: Failed to accept remote "
  83                                 "connection: %s", sdb_strerror(errno,
  84                                         buf, sizeof(buf)));
  85                 return -1;
  86         }
  87
  88         if (conn->client_addr.ss_family != AF_UNIX) {
  89                 sdb_log(SDB_LOG_ERR, "frontend: Accepted connection using "
  90                                 "unexpected family type %d", conn->client_addr.ss_family);
  91                 return -1;
  92         }
  93
  94         sock_fl = fcntl(conn->fd, F_GETFL);
  95         if (fcntl(conn->fd, F_SETFL, sock_fl | O_NONBLOCK)) {
  96                 char buf[1024];
  97                 sdb_log(SDB_LOG_ERR, "frontend: Failed to switch connection conn#%i "
  98                                 "to non-blocking mode: %s", conn->fd,
  99                                 sdb_strerror(errno, buf, sizeof(buf)));
 100                 return -1;
 101         }
 102
 103         sdb_log(SDB_LOG_DEBUG, "frontend: Accepted connection on fd=%i",
 104                         conn->fd);
 105
 106         conn->cmd = CONNECTION_IDLE;
 107         conn->cmd_len = 0;
 108
 109         /* update the object name */
 110         snprintf(obj->name + strlen(CONN_FD_PREFIX),
 111                         strlen(CONN_FD_PLACEHOLDER), "%i", conn->fd);
 112         return 0;
 113 } /* connection_init */
 114
 115 static void
 116 connection_destroy(sdb_object_t *obj)
 117 {
 118         sdb_conn_t *conn;
 119         size_t len;
 120
 121         assert(obj);
 122         conn = CONN(obj);
 123
 124         if (conn->buf) {
 125                 len = sdb_strbuf_len(conn->buf);
 126                 if (len)
 127                         sdb_log(SDB_LOG_INFO, "frontend: Discarding incomplete command "
 128                                         "(%zu byte%s left in buffer)", len, len == 1 ? "" : "s");
 129         }
 130
 131         sdb_log(SDB_LOG_DEBUG, "frontend: Closing connection on fd=%i",
 132                         conn->fd);
 133         close(conn->fd);
 134         conn->fd = -1;
 135
 136         sdb_strbuf_destroy(conn->buf);
 137         conn->buf = NULL;
 138         sdb_strbuf_destroy(conn->errbuf);
 139         conn->errbuf = NULL;
 140 } /* connection_destroy */
 141
 142 static sdb_type_t connection_type = {
 143         /* size = */ sizeof(sdb_conn_t),
 144         /* init = */ connection_init,
 145         /* destroy = */ connection_destroy,
 146 };
 147
 148 /*
 149  * connection handler functions
 150  */
 151
 152 static uint32_t
 153 connection_get_int32(sdb_conn_t *conn, size_t offset)
 154 {
 155         const char *data;
 156         uint32_t n;
 157
 158         assert(conn && (sdb_strbuf_len(conn->buf) >= offset + sizeof(uint32_t)));
 159
 160         data = sdb_strbuf_string(conn->buf);
 161         memcpy(&n, data + offset, sizeof(n));
 162         n = ntohl(n);
 163         return n;
 164 } /* connection_get_int32 */
 165
 166 static int
 167 command_handle(sdb_conn_t *conn)
 168 {
 169         int status = -1;
 170
 171         assert(conn && (conn->cmd != CONNECTION_IDLE));
 172
 173         sdb_log(SDB_LOG_DEBUG, "frontend: Handling command %u (len: %u)",
 174                         conn->cmd, conn->cmd_len);
 175
 176         /* reset */
 177         sdb_strbuf_sprintf(conn->errbuf, "");
 178
 179         switch (conn->cmd) {
 180                 case CONNECTION_PING:
 181                         status = sdb_connection_ping(conn);
 182                         break;
 183                 case CONNECTION_STARTUP:
 184                         status = sdb_fe_session_start(conn);
 185                         break;
 186
 187                 case CONNECTION_QUERY:
 188                 {
 189                         sdb_llist_t *parsetree;
 190                         sdb_conn_node_t *node = NULL;
 191
 192                         parsetree = sdb_fe_parse(sdb_strbuf_string(conn->buf),
 193                                         (int)conn->cmd_len);
 194                         if (! parsetree) {
 195                                 sdb_log(SDB_LOG_ERR, "frontend: Failed to parse query '%s'",
 196                                                 sdb_strbuf_string(conn->buf));
 197                                 status = -1;
 198                                 break;
 199                         }
 200
 201                         switch (sdb_llist_len(parsetree)) {
 202                                 case 0:
 203                                         /* skipping empty command */
 204                                         break;
 205                                 case 1:
 206                                         node = SDB_CONN_NODE(sdb_llist_get(parsetree, 0));
 207                                         break;
 208
 209                                 default:
 210                                         sdb_log(SDB_LOG_WARNING, "frontend: Ignoring %d command%s "
 211                                                         "in multi-statement query '%s'",
 212                                                         sdb_llist_len(parsetree) - 1,
 213                                                         sdb_llist_len(parsetree) == 2 ? "" : "s",
 214                                                         sdb_strbuf_string(conn->buf));
 215                                         node = SDB_CONN_NODE(sdb_llist_get(parsetree, 0));
 216                         }
 217
 218                         if (node)
 219                                 status = sdb_fe_exec(conn, node);
 220
 221                         sdb_llist_destroy(parsetree);
 222                 }
 223
 224                 case CONNECTION_LIST:
 225                         status = sdb_fe_list(conn);
 226                         break;
 227
 228                 default:
 229                 {
 230                         sdb_log(SDB_LOG_WARNING, "frontend: Ignoring invalid command %#x",
 231                                         conn->cmd);
 232                         sdb_strbuf_sprintf(conn->errbuf, "Invalid command %#x", conn->cmd);
 233                         status = -1;
 234                         break;
 235                 }
 236         }
 237
 238         if (status)
 239                 sdb_connection_send(conn, CONNECTION_ERROR,
 240                                 (uint32_t)sdb_strbuf_len(conn->errbuf),
 241                                 sdb_strbuf_string(conn->errbuf));
 242
 243         /* remove the command from the buffer */
 244         if (conn->cmd_len)
 245                 sdb_strbuf_skip(conn->buf, 0, conn->cmd_len);
 246         conn->cmd = CONNECTION_IDLE;
 247         conn->cmd_len = 0;
 248         return status;
 249 } /* command_handle */
 250
 251 /* initialize the connection state information */
 252 static int
 253 command_init(sdb_conn_t *conn)
 254 {
 255         size_t len;
 256
 257         assert(conn && (conn->cmd == CONNECTION_IDLE) && (! conn->cmd_len));
 258
 259         conn->cmd = connection_get_int32(conn, 0);
 260         conn->cmd_len = connection_get_int32(conn, sizeof(uint32_t));
 261
 262         len = 2 * sizeof(uint32_t);
 263         if (conn->cmd == CONNECTION_IDLE)
 264                 len += conn->cmd_len;
 265         sdb_strbuf_skip(conn->buf, 0, len);
 266         return 0;
 267 } /* command_init */
 268
 269 /* returns negative value on error, 0 on EOF, number of octets else */
 270 static ssize_t
 271 connection_read(sdb_conn_t *conn)
 272 {
 273         ssize_t n = 0;
 274
 275         while (42) {
 276                 ssize_t status;
 277
 278                 errno = 0;
 279                 status = sdb_strbuf_read(conn->buf, conn->fd, 1024);
 280                 if (status < 0) {
 281                         if ((errno == EAGAIN) || (errno == EWOULDBLOCK))
 282                                 break;
 283                         return (int)status;
 284                 }
 285                 else if (! status) /* EOF */
 286                         break;
 287
 288                 n += status;
 289         }
 290
 291         return n;
 292 } /* connection_read */
 293
 294 /*
 295  * public API
 296  */
 297
 298 sdb_conn_t *
 299 sdb_connection_accept(int fd)
 300 {
 301         if (fd < 0)
 302                 return NULL;
 303
 304         /* the placeholder will be replaced with the accepted file
 305          * descriptor when initializing the object */
 306         return CONN(sdb_object_create(CONN_FD_PREFIX CONN_FD_PLACEHOLDER,
 307                                 connection_type, fd));
 308 } /* sdb_connection_create */
 309
 310 void
 311 sdb_connection_close(sdb_conn_t *conn)
 312 {
 313         sdb_object_deref(SDB_OBJ(conn));
 314 } /* sdb_connection_close */
 315
 316 ssize_t
 317 sdb_connection_read(sdb_conn_t *conn)
 318 {
 319         ssize_t n = 0;
 320
 321         while (42) {
 322                 ssize_t status = connection_read(conn);
 323
 324                 if ((conn->cmd == CONNECTION_IDLE) && (! conn->cmd_len)
 325                                 && (sdb_strbuf_len(conn->buf) >= 2 * sizeof(int32_t)))
 326                         command_init(conn);
 327                 if ((conn->cmd != CONNECTION_IDLE)
 328                                 && (sdb_strbuf_len(conn->buf) >= conn->cmd_len))
 329                         command_handle(conn);
 330
 331                 if (status <= 0)
 332                         break;
 333
 334                 n += status;
 335         }
 336         return n;
 337 } /* sdb_connection_read */
 338
 339 ssize_t
 340 sdb_connection_send(sdb_conn_t *conn, uint32_t code,
 341                 uint32_t msg_len, const char *msg)
 342 {
 343         ssize_t status;
 344
 345         if ((! conn) || (conn->fd < 0))
 346                 return -1;
 347
 348         status = sdb_proto_send_msg(conn->fd, code, msg_len, msg);
 349         if (status < 0) {
 350                 char errbuf[1024];
 351
 352                 sdb_log(SDB_LOG_ERR, "frontend: Failed to send msg "
 353                                 "(code: %u, len: %u) to client: %s", code, msg_len,
 354                                 sdb_strerror(errno, errbuf, sizeof(errbuf)));
 355         }
 356         return status;
 357 } /* sdb_connection_send */
 358
 359 int
 360 sdb_connection_ping(sdb_conn_t *conn)
 361 {
 362         if ((! conn) || (conn->cmd != CONNECTION_PING))
 363                 return -1;
 364
 365         /* we're alive */
 366         sdb_connection_send(conn, CONNECTION_OK, 0, NULL);
 367         return 0;
 368 } /* sdb_connection_ping */
 369
 370 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */
 371