release/src/router/transmission/daemon/watch.c

   1 /*
   2  * This file Copyright (C) Mnemosyne LLC
   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 version 2
   6  * as published by the Free Software Foundation.
   7  *
   8  * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
   9  *
  10  * $Id: watch.c 13748 2013-01-03 23:54:25Z jordan $
  11  */
  12 #ifdef WITH_INOTIFY
  13   #include <sys/inotify.h>
  14   #include <sys/select.h>
  15   #include <unistd.h> /* close */
  16 #else
  17   #include <sys/types.h> /* stat */
  18   #include <sys/stat.h> /* stat */
  19   #include <event2/buffer.h> /* evbuffer */
  20 #endif
  21
  22 #include <errno.h>
  23 #include <string.h> /* strlen () */
  24 #include <stdio.h> /* perror () */
  25
  26 #include <dirent.h> /* readdir */
  27
  28 #include <libtransmission/transmission.h>
  29 #include <libtransmission/utils.h> /* tr_buildPath (), tr_inf () */
  30 #include "watch.h"
  31
  32 struct dtr_watchdir
  33 {
  34     tr_session * session;
  35     char * dir;
  36     dtr_watchdir_callback * callback;
  37 #ifdef WITH_INOTIFY
  38     int inotify_fd;
  39 #else /* readdir implementation */
  40     time_t lastTimeChecked;
  41     struct evbuffer * lastFiles;
  42 #endif
  43 };
  44
  45 /***
  46 ****  INOTIFY IMPLEMENTATION
  47 ***/
  48
  49 #if defined (WITH_INOTIFY)
  50
  51 /* how many inotify events to try to batch into a single read */
  52 #define EVENT_BATCH_COUNT 50
  53 /* size of the event structure, not counting name */
  54 #define EVENT_SIZE (sizeof (struct inotify_event))
  55 /* reasonable guess as to size of 50 events */
  56 #define BUF_LEN (EVENT_BATCH_COUNT * (EVENT_SIZE + 16) + 2048)
  57
  58 #define DTR_INOTIFY_MASK (IN_CLOSE_WRITE|IN_MOVED_TO|IN_CREATE|IN_ONLYDIR)
  59
  60 static void
  61 watchdir_new_impl (dtr_watchdir * w)
  62 {
  63     int i;
  64     DIR * odir;
  65     w->inotify_fd = inotify_init ();
  66
  67     if (w->inotify_fd < 0)
  68     {
  69         i = -1;
  70     }
  71     else
  72     {
  73         tr_inf ("Using inotify to watch directory \"%s\"", w->dir);
  74         i = inotify_add_watch (w->inotify_fd, w->dir, DTR_INOTIFY_MASK);
  75     }
  76
  77     if (i < 0)
  78     {
  79         tr_err ("Unable to watch \"%s\": %s", w->dir, tr_strerror (errno));
  80     }
  81     else if ((odir = opendir (w->dir)))
  82     {
  83         struct dirent * d;
  84
  85         while ((d = readdir (odir)))
  86         {
  87             const char * name = d->d_name;
  88
  89             if (!tr_str_has_suffix (name, ".torrent")) /* skip non-torrents */
  90                 continue;
  91
  92             tr_inf ("Found new .torrent file \"%s\" in watchdir \"%s\"", name, w->dir);
  93             w->callback (w->session, w->dir, name);
  94         }
  95
  96         closedir (odir);
  97     }
  98
  99 }
 100 static void
 101 watchdir_free_impl (dtr_watchdir * w)
 102 {
 103     if (w->inotify_fd >= 0)
 104     {
 105         inotify_rm_watch (w->inotify_fd, DTR_INOTIFY_MASK);
 106
 107         close (w->inotify_fd);
 108     }
 109 }
 110 static void
 111 watchdir_update_impl (dtr_watchdir * w)
 112 {
 113     int ret;
 114     fd_set rfds;
 115     struct timeval time;
 116     const int fd = w->inotify_fd;
 117
 118     /* timeout after one second */
 119     time.tv_sec = 1;
 120     time.tv_usec = 0;
 121
 122     /* make the fd_set hold the inotify fd */
 123     FD_ZERO (&rfds);
 124     FD_SET (fd, &rfds);
 125
 126     /* check for added files */
 127     ret = select (fd+1, &rfds, NULL, NULL, &time);
 128     if (ret < 0) {
 129         perror ("select");
 130     } else if (!ret) {
 131         /* timed out! */
 132     } else if (FD_ISSET (fd, &rfds)) {
 133         int i = 0;
 134         char buf[BUF_LEN];
 135         int len = read (fd, buf, sizeof (buf));
 136         while (i < len) {
 137             struct inotify_event * event = (struct inotify_event *) &buf[i];
 138             const char * name = event->name;
 139             if (tr_str_has_suffix (name, ".torrent"))
 140             {
 141                 tr_inf ("Found new .torrent file \"%s\" in watchdir \"%s\"", name, w->dir);
 142                 w->callback (w->session, w->dir, name);
 143             }
 144             i += EVENT_SIZE +  event->len;
 145         }
 146     }
 147 }
 148
 149 #else /* WITH_INOTIFY */
 150
 151 /***
 152 ****  READDIR IMPLEMENTATION
 153 ***/
 154
 155 #define WATCHDIR_POLL_INTERVAL_SECS 10
 156
 157 #define FILE_DELIMITER '\t'
 158
 159 static void
 160 watchdir_new_impl (dtr_watchdir * w UNUSED)
 161 {
 162     tr_inf ("Using readdir to watch directory \"%s\"", w->dir);
 163     w->lastFiles = evbuffer_new ();
 164 }
 165 static void
 166 watchdir_free_impl (dtr_watchdir * w)
 167 {
 168     evbuffer_free (w->lastFiles);
 169 }
 170
 171 static char*
 172 get_key_from_file (const char * filename, const size_t len)
 173 {
 174     return tr_strdup_printf ("%c%*.*s%d", FILE_DELIMITER, (int)len, (int)len, filename, FILE_DELIMITER);
 175 }
 176
 177 static void
 178 add_file_to_list (struct evbuffer * buf, const char * filename, size_t len)
 179 {
 180     char * key = get_key_from_file (filename, len);
 181     evbuffer_add (buf, key, strlen (key));
 182     tr_free (key);
 183 }
 184 static bool
 185 is_file_in_list (struct evbuffer * buf, const char * filename, size_t len)
 186 {
 187     bool in_list;
 188     struct evbuffer_ptr ptr;
 189     char * key = get_key_from_file (filename, len);
 190
 191     ptr = evbuffer_search (buf, key, strlen (key), NULL);
 192     in_list = ptr.pos != -1;
 193
 194     tr_free (key);
 195     return in_list;
 196 }
 197 static void
 198 watchdir_update_impl (dtr_watchdir * w)
 199 {
 200     struct stat sb;
 201     DIR * odir;
 202     const time_t oldTime = w->lastTimeChecked;
 203     const char * dirname = w->dir;
 204     struct evbuffer * curFiles = evbuffer_new ();
 205
 206     if ((oldTime + WATCHDIR_POLL_INTERVAL_SECS < time (NULL))
 207          && !stat (dirname, &sb)
 208          && S_ISDIR (sb.st_mode)
 209          && ((odir = opendir (dirname))))
 210     {
 211         struct dirent * d;
 212
 213         for (d = readdir (odir); d != NULL; d = readdir (odir))
 214         {
 215             size_t len;
 216             const char * name = d->d_name;
 217
 218             if (!name || *name=='.') /* skip dotfiles */
 219                 continue;
 220             if (!tr_str_has_suffix (name, ".torrent")) /* skip non-torrents */
 221                 continue;
 222
 223             len = strlen (name);
 224             add_file_to_list (curFiles, name, len);
 225
 226             /* if this file wasn't here last time, try adding it */
 227             if (!is_file_in_list (w->lastFiles, name, len)) {
 228                 tr_inf ("Found new .torrent file \"%s\" in watchdir \"%s\"", name, w->dir);
 229                 w->callback (w->session, w->dir, name);
 230             }
 231         }
 232
 233         closedir (odir);
 234         w->lastTimeChecked = time (NULL);
 235         evbuffer_free (w->lastFiles);
 236         w->lastFiles = curFiles;
 237     }
 238 }
 239
 240 #endif
 241
 242 /***
 243 ****
 244 ***/
 245
 246 dtr_watchdir*
 247 dtr_watchdir_new (tr_session * session, const char * dir, dtr_watchdir_callback * callback)
 248 {
 249     dtr_watchdir * w = tr_new0 (dtr_watchdir, 1);
 250
 251     w->session = session;
 252     w->dir = tr_strdup (dir);
 253     w->callback = callback;
 254
 255     watchdir_new_impl (w);
 256
 257     return w;
 258 }
 259
 260 void
 261 dtr_watchdir_update (dtr_watchdir * w)
 262 {
 263     if (w != NULL)
 264         watchdir_update_impl (w);
 265 }
 266
 267 void
 268 dtr_watchdir_free (dtr_watchdir * w)
 269 {
 270     if (w != NULL)
 271     {
 272         watchdir_free_impl (w);
 273         tr_free (w->dir);
 274         tr_free (w);
 275     }
 276 }