src/bacon-message-connection.c

   1 /*
   2  * Copyright (C) 2003 Bastien Nocera <hadess@hadess.net>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  17  *
  18  * The Totem project hereby grant permission for non-gpl compatible GStreamer
  19  * plugins to be used and distributed together with GStreamer and Totem. This
  20  * permission are above and beyond the permissions granted by the GPL license
  21  * Totem is covered by.
  22  *
  23  * Monday 7th February 2005: Christian Schaller: Add excemption clause.
  24  * See license_change file for details.
  25  *
  26  */
  27
  28 #include <sys/types.h>
  29 #include <sys/stat.h>
  30 #include <fcntl.h>
  31 #include <stdio.h>
  32 #include <string.h>
  33 #include <unistd.h>
  34 #include <sys/types.h>
  35 #include <sys/socket.h>
  36 #include <sys/un.h>
  37 #include <errno.h>
  38
  39 #include "bacon-message-connection.h"
  40
  41 #ifndef UNIX_PATH_MAX
  42 #define UNIX_PATH_MAX 108
  43 #endif
  44
  45 struct BaconMessageConnection {
  46         /* A server accepts connections */
  47         gboolean is_server;
  48
  49         /* The socket path itself */
  50         char *path;
  51
  52         /* File descriptor of the socket */
  53         int fd;
  54         /* Channel to watch */
  55         GIOChannel *chan;
  56         /* Event id returned by g_io_add_watch() */
  57         int conn_id;
  58
  59         /* Connections accepted by this connection */
  60         GSList *accepted_connections;
  61
  62         /* callback */
  63         void (*func) (const char *message, gpointer user_data);
  64         gpointer data;
  65 };
  66
  67 static gboolean
  68 test_is_socket (const char *path)
  69 {
  70         struct stat s;
  71
  72         if (stat (path, &s) == -1)
  73                 return FALSE;
  74
  75         if (S_ISSOCK (s.st_mode))
  76                 return TRUE;
  77
  78         return FALSE;
  79 }
  80
  81 static gboolean
  82 is_owned_by_user_and_socket (const char *path)
  83 {
  84         struct stat s;
  85
  86         if (stat (path, &s) == -1)
  87                 return FALSE;
  88
  89         if (s.st_uid != geteuid ())
  90                 return FALSE;
  91
  92         if ((s.st_mode & S_IFSOCK) != S_IFSOCK)
  93                 return FALSE;
  94
  95         return TRUE;
  96 }
  97
  98 static gboolean server_cb (GIOChannel *source,
  99                            GIOCondition condition, gpointer data);
 100
 101 static gboolean
 102 setup_connection (BaconMessageConnection *conn)
 103 {
 104         int fdflags;
 105
 106         g_return_val_if_fail (conn->chan == NULL, FALSE);
 107
 108         /* Add CLOEXEC flag on the fd to make sure the socket get closed
 109          * if exec is called. */
 110         fdflags = fcntl (conn->fd, F_GETFD, 0);
 111         if (fdflags >= 0) {
 112                 fdflags |= FD_CLOEXEC;
 113                 fcntl (conn->fd, F_SETFD, fdflags);
 114         }
 115
 116         conn->chan = g_io_channel_unix_new (conn->fd);
 117         if (!conn->chan) {
 118                 return FALSE;
 119         }
 120         g_io_channel_set_line_term (conn->chan, "\n", 1);
 121         conn->conn_id = g_io_add_watch (conn->chan, G_IO_IN, server_cb, conn);
 122
 123         return TRUE;
 124 }
 125
 126 static void
 127 accept_new_connection (BaconMessageConnection *server_conn)
 128 {
 129         BaconMessageConnection *conn;
 130         int alen;
 131
 132         g_return_if_fail (server_conn->is_server);
 133
 134         conn = g_new0 (BaconMessageConnection, 1);
 135         conn->is_server = FALSE;
 136         conn->func = server_conn->func;
 137         conn->data = server_conn->data;
 138
 139         conn->fd = accept (server_conn->fd, NULL, (guint *)&alen);
 140
 141         server_conn->accepted_connections =
 142                 g_slist_prepend (server_conn->accepted_connections, conn);
 143
 144         setup_connection (conn);
 145 }
 146
 147 static gboolean
 148 server_cb (GIOChannel *source, GIOCondition condition, gpointer data)
 149 {
 150         BaconMessageConnection *conn = (BaconMessageConnection *)data;
 151         char *message, *subs, buf;
 152         int cd, rc, offset;
 153         gboolean finished;
 154
 155         offset = 0;
 156         if (conn->is_server && conn->fd == g_io_channel_unix_get_fd (source)) {
 157                 accept_new_connection (conn);
 158                 return TRUE;
 159         }
 160         message = g_malloc (1);
 161         cd = conn->fd;
 162         rc = read (cd, &buf, 1);
 163         while (rc > 0 && buf != '\n')
 164         {
 165                 message = g_realloc (message, rc + offset + 1);
 166                 message[offset] = buf;
 167                 offset = offset + rc;
 168                 rc = read (cd, &buf, 1);
 169         }
 170         if (rc <= 0) {
 171                 g_io_channel_shutdown (conn->chan, FALSE, NULL);
 172                 g_io_channel_unref (conn->chan);
 173                 conn->chan = NULL;
 174                 close (conn->fd);
 175                 conn->fd = -1;
 176                 g_free (message);
 177                 conn->conn_id = 0;
 178
 179                 return FALSE;
 180         }
 181         message[offset] = '\0';
 182
 183         subs = message;
 184         finished = FALSE;
 185
 186         while (finished == FALSE && *subs != '\0')
 187         {
 188                 if (conn->func != NULL)
 189                         (*conn->func) (subs, conn->data);
 190
 191                 subs += strlen (subs) + 1;
 192                 if (subs - message >= offset)
 193                         finished = TRUE;
 194         }
 195
 196         g_free (message);
 197
 198         return TRUE;
 199 }
 200
 201 static char *
 202 find_file_with_pattern (const char *dir, const char *pattern)
 203 {
 204         GDir *filedir;
 205         char *found_filename;
 206         const char *filename;
 207         GPatternSpec *pat;
 208
 209         filedir = g_dir_open (dir, 0, NULL);
 210         if (filedir == NULL)
 211                 return NULL;
 212
 213         pat = g_pattern_spec_new (pattern);
 214         if (pat == NULL)
 215         {
 216                 g_dir_close (filedir);
 217                 return NULL;
 218         }
 219
 220         found_filename = NULL;
 221
 222         while ((filename = g_dir_read_name (filedir)))
 223         {
 224                 if (g_pattern_match_string (pat, filename))
 225                 {
 226                         char *tmp = g_build_filename (dir, filename, NULL);
 227                         if (is_owned_by_user_and_socket (tmp))
 228                                 found_filename = g_strdup (filename);
 229                         g_free (tmp);
 230                 }
 231
 232                 if (found_filename != NULL)
 233                         break;
 234         }
 235
 236         g_pattern_spec_free (pat);
 237         g_dir_close (filedir);
 238
 239         return found_filename;
 240 }
 241
 242 static char *
 243 socket_filename (const char *prefix)
 244 {
 245         char *pattern, *newfile, *path, *filename;
 246         const char *tmpdir;
 247
 248         pattern = g_strdup_printf ("%s.%s.*", prefix, g_get_user_name ());
 249         tmpdir = g_get_tmp_dir ();
 250         filename = find_file_with_pattern (tmpdir, pattern);
 251         if (filename == NULL)
 252         {
 253                 newfile = g_strdup_printf ("%s.%s.%u", prefix,
 254                                 g_get_user_name (), g_random_int ());
 255                 path = g_build_filename (tmpdir, newfile, NULL);
 256                 g_free (newfile);
 257         } else {
 258                 path = g_build_filename (tmpdir, filename, NULL);
 259                 g_free (filename);
 260         }
 261
 262         g_free (pattern);
 263         return path;
 264 }
 265
 266 static gboolean
 267 try_server (BaconMessageConnection *conn)
 268 {
 269         struct sockaddr_un uaddr;
 270
 271         uaddr.sun_family = AF_UNIX;
 272         strncpy (uaddr.sun_path, conn->path,
 273                         MIN (strlen(conn->path)+1, UNIX_PATH_MAX));
 274         conn->fd = socket (PF_UNIX, SOCK_STREAM, 0);
 275         if (bind (conn->fd, (struct sockaddr *) &uaddr, sizeof (uaddr)) == -1)
 276         {
 277                 conn->fd = -1;
 278                 return FALSE;
 279         }
 280         listen (conn->fd, 5);
 281
 282         return setup_connection (conn);
 283 }
 284
 285 static gboolean
 286 try_client (BaconMessageConnection *conn)
 287 {
 288         struct sockaddr_un uaddr;
 289
 290         uaddr.sun_family = AF_UNIX;
 291         strncpy (uaddr.sun_path, conn->path,
 292                         MIN(strlen(conn->path)+1, UNIX_PATH_MAX));
 293         conn->fd = socket (PF_UNIX, SOCK_STREAM, 0);
 294         if (connect (conn->fd, (struct sockaddr *) &uaddr,
 295                                 sizeof (uaddr)) == -1)
 296         {
 297                 conn->fd = -1;
 298                 return FALSE;
 299         }
 300
 301         return setup_connection (conn);
 302 }
 303
 304 BaconMessageConnection *
 305 bacon_message_connection_new (const char *prefix)
 306 {
 307         BaconMessageConnection *conn;
 308
 309         g_return_val_if_fail (prefix != NULL, NULL);
 310
 311         conn = g_new0 (BaconMessageConnection, 1);
 312         conn->path = socket_filename (prefix);
 313
 314         if (test_is_socket (conn->path) == FALSE)
 315         {
 316                 if (!try_server (conn))
 317                 {
 318                         bacon_message_connection_free (conn);
 319                         return NULL;
 320                 }
 321
 322                 conn->is_server = TRUE;
 323                 return conn;
 324         }
 325
 326         if (try_client (conn) == FALSE)
 327         {
 328                 unlink (conn->path);
 329                 try_server (conn);
 330                 if (conn->fd == -1)
 331                 {
 332                         bacon_message_connection_free (conn);
 333                         return NULL;
 334                 }
 335
 336                 conn->is_server = TRUE;
 337                 return conn;
 338         }
 339
 340         conn->is_server = FALSE;
 341         return conn;
 342 }
 343
 344 void
 345 bacon_message_connection_free (BaconMessageConnection *conn)
 346 {
 347         GSList *child_conn;
 348
 349         g_return_if_fail (conn != NULL);
 350         /* Only servers can accept other connections */
 351         g_return_if_fail (conn->is_server != FALSE ||
 352                           conn->accepted_connections == NULL);
 353
 354         child_conn = conn->accepted_connections;
 355         while (child_conn != NULL) {
 356                 bacon_message_connection_free (child_conn->data);
 357                 child_conn = g_slist_next (child_conn);
 358         }
 359         g_slist_free (conn->accepted_connections);
 360
 361         if (conn->conn_id) {
 362                 g_source_remove (conn->conn_id);
 363                 conn->conn_id = 0;
 364         }
 365         if (conn->chan) {
 366                 g_io_channel_shutdown (conn->chan, FALSE, NULL);
 367                 g_io_channel_unref (conn->chan);
 368         }
 369
 370         if (conn->is_server != FALSE) {
 371                 unlink (conn->path);
 372         }
 373         if (conn->fd != -1) {
 374                 close (conn->fd);
 375         }
 376
 377         g_free (conn->path);
 378         g_free (conn);
 379 }
 380
 381 void
 382 bacon_message_connection_set_callback (BaconMessageConnection *conn,
 383                                        BaconMessageReceivedFunc func,
 384                                        gpointer user_data)
 385 {
 386         g_return_if_fail (conn != NULL);
 387
 388         conn->func = func;
 389         conn->data = user_data;
 390 }
 391
 392 void
 393 bacon_message_connection_send (BaconMessageConnection *conn,
 394                                const char *message)
 395 {
 396         g_return_if_fail (conn != NULL);
 397         g_return_if_fail (message != NULL);
 398
 399         g_io_channel_write_chars (conn->chan, message, strlen (message),
 400                                   NULL, NULL);
 401         g_io_channel_write_chars (conn->chan, "\n", 1, NULL, NULL);
 402         g_io_channel_flush (conn->chan, NULL);
 403 }
 404
 405 gboolean
 406 bacon_message_connection_get_is_server (BaconMessageConnection *conn)
 407 {
 408         g_return_val_if_fail (conn != NULL, FALSE);
 409
 410         return conn->is_server;
 411 }
 412