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_LIST:
 188                         status = sdb_fe_list(conn);
 189                         break;
 190
 191                 default:
 192                 {
 193                         sdb_log(SDB_LOG_WARNING, "frontend: Ignoring invalid command");
 194                         sdb_strbuf_sprintf(conn->errbuf, "Invalid command %#x", conn->cmd);
 195                         status = -1;
 196                         break;
 197                 }
 198         }
 199
 200         if (status)
 201                 sdb_connection_send(conn, CONNECTION_ERROR,
 202                                 (uint32_t)sdb_strbuf_len(conn->errbuf),
 203                                 sdb_strbuf_string(conn->errbuf));
 204
 205         /* remove the command from the buffer */
 206         if (conn->cmd_len)
 207                 sdb_strbuf_skip(conn->buf, 0, conn->cmd_len);
 208         conn->cmd = CONNECTION_IDLE;
 209         conn->cmd_len = 0;
 210         return status;
 211 } /* command_handle */
 212
 213 /* initialize the connection state information */
 214 static int
 215 command_init(sdb_conn_t *conn)
 216 {
 217         size_t len;
 218
 219         assert(conn && (conn->cmd == CONNECTION_IDLE) && (! conn->cmd_len));
 220
 221         conn->cmd = connection_get_int32(conn, 0);
 222         conn->cmd_len = connection_get_int32(conn, sizeof(uint32_t));
 223
 224         len = 2 * sizeof(uint32_t);
 225         if (conn->cmd == CONNECTION_IDLE)
 226                 len += conn->cmd_len;
 227         sdb_strbuf_skip(conn->buf, 0, len);
 228         return 0;
 229 } /* command_init */
 230
 231 /* returns negative value on error, 0 on EOF, number of octets else */
 232 static ssize_t
 233 connection_read(sdb_conn_t *conn)
 234 {
 235         ssize_t n = 0;
 236
 237         while (42) {
 238                 ssize_t status;
 239
 240                 errno = 0;
 241                 status = sdb_strbuf_read(conn->buf, conn->fd, 1024);
 242                 if (status < 0) {
 243                         if ((errno == EAGAIN) || (errno == EWOULDBLOCK))
 244                                 break;
 245                         return (int)status;
 246                 }
 247                 else if (! status) /* EOF */
 248                         break;
 249
 250                 n += status;
 251         }
 252
 253         return n;
 254 } /* connection_read */
 255
 256 /*
 257  * public API
 258  */
 259
 260 sdb_conn_t *
 261 sdb_connection_accept(int fd)
 262 {
 263         if (fd < 0)
 264                 return NULL;
 265
 266         /* the placeholder will be replaced with the accepted file
 267          * descriptor when initializing the object */
 268         return CONN(sdb_object_create(CONN_FD_PREFIX CONN_FD_PLACEHOLDER,
 269                                 connection_type, fd));
 270 } /* sdb_connection_create */
 271
 272 void
 273 sdb_connection_close(sdb_conn_t *conn)
 274 {
 275         sdb_object_deref(SDB_OBJ(conn));
 276 } /* sdb_connection_close */
 277
 278 ssize_t
 279 sdb_connection_read(sdb_conn_t *conn)
 280 {
 281         ssize_t n = 0;
 282
 283         while (42) {
 284                 ssize_t status = connection_read(conn);
 285
 286                 if ((conn->cmd == CONNECTION_IDLE) && (! conn->cmd_len)
 287                                 && (sdb_strbuf_len(conn->buf) >= 2 * sizeof(int32_t)))
 288                         command_init(conn);
 289                 if ((conn->cmd != CONNECTION_IDLE)
 290                                 && (sdb_strbuf_len(conn->buf) >= conn->cmd_len))
 291                         command_handle(conn);
 292
 293                 if (status <= 0)
 294                         break;
 295
 296                 n += status;
 297         }
 298         return n;
 299 } /* sdb_connection_read */
 300
 301 ssize_t
 302 sdb_connection_send(sdb_conn_t *conn, uint32_t code,
 303                 uint32_t msg_len, const char *msg)
 304 {
 305         ssize_t status;
 306
 307         if ((! conn) || (conn->fd < 0))
 308                 return -1;
 309
 310         status = sdb_proto_send_msg(conn->fd, code, msg_len, msg);
 311         if (status < 0) {
 312                 char errbuf[1024];
 313
 314                 sdb_log(SDB_LOG_ERR, "frontend: Failed to send msg "
 315                                 "(code: %u, len: %u) to client: %s", code, msg_len,
 316                                 sdb_strerror(errno, errbuf, sizeof(errbuf)));
 317         }
 318         return status;
 319 } /* sdb_connection_send */
 320
 321 int
 322 sdb_connection_ping(sdb_conn_t *conn)
 323 {
 324         if ((! conn) || (conn->cmd != CONNECTION_PING))
 325                 return -1;
 326
 327         /* we're alive */
 328         sdb_connection_send(conn, CONNECTION_OK, 0, NULL);
 329         return 0;
 330 } /* sdb_connection_ping */
 331
 332 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */
 333