udevtrigger.c

   1 /*
   2  * Copyright (C) 2004-2006 Kay Sievers <kay@vrfy.org>
   3  * Copyright (C) 2006 Hannes Reinecke <hare@suse.de>
   4  *
   5  *      This program is free software; you can redistribute it and/or modify it
   6  *      under the terms of the GNU General Public License as published by the
   7  *      Free Software Foundation version 2 of the License.
   8  *
   9  *      This program is distributed in the hope that it will be useful, but
  10  *      WITHOUT ANY WARRANTY; without even the implied warranty of
  11  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  *      General Public License for more details.
  13  *
  14  *      You should have received a copy of the GNU General Public License along
  15  *      with this program; if not, write to the Free Software Foundation, Inc.,
  16  *      51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  17  *
  18  */
  19
  20 #include <stdlib.h>
  21 #include <stddef.h>
  22 #include <stdarg.h>
  23 #include <stdio.h>
  24 #include <stdbool.h>
  25 #include <unistd.h>
  26 #include <getopt.h>
  27 #include <errno.h>
  28 #include <dirent.h>
  29 #include <fcntl.h>
  30 #include <syslog.h>
  31 #include <sys/stat.h>
  32 #include <sys/types.h>
  33 #include <string.h>
  34
  35 #define PATH_SIZE 512
  36
  37 #ifndef strlcpy
  38 #define strlcpy(d,s,l) (strncpy(d,s,l), (d)[(l)-1] = '\0')
  39 #endif
  40
  41 #ifndef strlcat
  42 #define strlcat(d,s,l) strncat(d,s,(l)-strlen(d)-1)
  43 #endif
  44
  45 static int verbose;
  46 static int dry_run;
  47
  48 static void log_message(int priority, const char *format, ...)
  49 {
  50         va_list args;
  51
  52         va_start(args, format);
  53         vsyslog(priority, format, args);
  54         va_end(args);
  55 }
  56
  57 #undef err
  58 #define err(format, arg...)                         \
  59     do {                                    \
  60         log_message(LOG_ERR ,"%s: " format ,__FUNCTION__ ,## arg);  \
  61     } while (0)
  62
  63 #undef info
  64 #define info(format, arg...)                            \
  65     do {                                    \
  66         log_message(LOG_INFO ,"%s: " format ,__FUNCTION__ ,## arg); \
  67     } while (0)
  68
  69 #ifdef DEBUG
  70 #undef dbg
  71 #define dbg(format, arg...)                         \
  72     do {                                    \
  73         log_message(LOG_DEBUG ,"%s: " format ,__FUNCTION__ ,## arg);    \
  74     } while (0)
  75 #else
  76 #define dbg(...) do {} while(0)
  77 #endif
  78
  79
  80 static void trigger_uevent(const char *devpath)
  81 {
  82         char filename[PATH_SIZE];
  83         int fd;
  84
  85         strlcpy(filename, "/sys", sizeof(filename));
  86         strlcat(filename, devpath, sizeof(filename));
  87         strlcat(filename, "/uevent", sizeof(filename));
  88
  89         if (verbose)
  90                 printf("%s\n", devpath);
  91
  92         if (dry_run)
  93                 return;
  94
  95         fd = open(filename, O_WRONLY);
  96         if (fd < 0) {
  97                 dbg("error on opening %s: %s\n", filename, strerror(errno));
  98                 return;
  99         }
 100
 101         if (write(fd, "add", 3) < 0)
 102                 info("error on triggering %s: %s\n", filename, strerror(errno));
 103
 104         close(fd);
 105 }
 106
 107 static int sysfs_resolve_link(char *devpath, size_t size)
 108 {
 109         char link_path[PATH_SIZE];
 110         char link_target[PATH_SIZE];
 111         int len;
 112         int i;
 113         int back;
 114
 115         strlcpy(link_path, "/sys", sizeof(link_path));
 116         strlcat(link_path, devpath, sizeof(link_path));
 117         len = readlink(link_path, link_target, sizeof(link_target));
 118         if (len <= 0)
 119                 return -1;
 120         link_target[len] = '\0';
 121         dbg("path link '%s' points to '%s'", devpath, link_target);
 122
 123         for (back = 0; strncmp(&link_target[back * 3], "../", 3) == 0; back++)
 124                 ;
 125         dbg("base '%s', tail '%s', back %i", devpath, &link_target[back * 3], back);
 126         for (i = 0; i <= back; i++) {
 127                 char *pos = strrchr(devpath, '/');
 128
 129                 if (pos == NULL)
 130                         return -1;
 131                 pos[0] = '\0';
 132         }
 133         dbg("after moving back '%s'", devpath);
 134         strlcat(devpath, "/", size);
 135         strlcat(devpath, &link_target[back * 3], size);
 136         return 0;
 137 }
 138
 139 static bool device_has_attribute(const char *path, const char *attr,
 140                                  mode_t mode)
 141 {
 142         char filename[PATH_SIZE];
 143         struct stat statbuf;
 144
 145         strlcpy(filename, path, sizeof(filename));
 146         strlcat(filename, attr, sizeof(filename));
 147
 148         if (stat(filename, &statbuf) < 0)
 149                 return false;
 150
 151         if (!(statbuf.st_mode & mode))
 152                 return false;
 153
 154         return true;
 155 }
 156
 157 static int device_list_insert(const char *path)
 158 {
 159         char devpath[PATH_SIZE];
 160         struct stat statbuf;
 161
 162         dbg("add '%s'" , path);
 163
 164         /* we only have a device, if we have a dev and an uevent file */
 165         if (!device_has_attribute(path, "/dev", S_IRUSR) ||
 166             !device_has_attribute(path, "/uevent", S_IWUSR))
 167                 return -1;
 168
 169         strlcpy(devpath, &path[4], sizeof(devpath));
 170
 171         /* resolve possible link to real target */
 172         if (lstat(path, &statbuf) < 0)
 173                 return -1;
 174         if (S_ISLNK(statbuf.st_mode))
 175                 if (sysfs_resolve_link(devpath, sizeof(devpath)) != 0)
 176                         return -1;
 177
 178         trigger_uevent(devpath);
 179         return 0;
 180 }
 181
 182 static void scan_subdir(const char *base)
 183 {
 184         DIR *dir;
 185         struct dirent *dent;
 186
 187         dir = opendir(base);
 188         if (dir == NULL)
 189                 return;
 190
 191         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 192                 char dirname[PATH_SIZE];
 193
 194                 if (dent->d_name[0] == '.')
 195                         continue;
 196
 197                 strlcpy(dirname, base, sizeof(dirname));
 198                 strlcat(dirname, "/", sizeof(dirname));
 199                 strlcat(dirname, dent->d_name, sizeof(dirname));
 200                 device_list_insert(dirname);
 201         }
 202
 203         closedir(dir);
 204 }
 205
 206 static void scan_subsystem(const char *subsys)
 207 {
 208         char base[PATH_SIZE];
 209         DIR *dir;
 210         struct dirent *dent;
 211
 212         strlcpy(base, "/sys/", sizeof(base));
 213         strlcat(base, subsys, sizeof(base));
 214
 215         dir = opendir(base);
 216         if (dir == NULL)
 217                 return;
 218
 219         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 220                 char dirname[PATH_SIZE];
 221
 222                 if (dent->d_name[0] == '.')
 223                         continue;
 224
 225                 strlcpy(dirname, base, sizeof(dirname));
 226                 strlcat(dirname, "/", sizeof(dirname));
 227                 strlcat(dirname, dent->d_name, sizeof(dirname));
 228                 strlcat(dirname, "/devices", sizeof(dirname));
 229
 230                 /* look for devices */
 231                 scan_subdir(dirname);
 232         }
 233
 234         closedir(dir);
 235 }
 236
 237 static void scan_block(void)
 238 {
 239         char base[PATH_SIZE];
 240         DIR *dir;
 241         struct dirent *dent;
 242
 243         strlcpy(base, "/sys/block", sizeof(base));
 244
 245         dir = opendir(base);
 246         if (dir == NULL)
 247                 return;
 248
 249         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 250                 char dirname[PATH_SIZE];
 251
 252                 if (dent->d_name[0] == '.')
 253                         continue;
 254
 255                 strlcpy(dirname, base, sizeof(dirname));
 256                 strlcat(dirname, "/", sizeof(dirname));
 257                 strlcat(dirname, dent->d_name, sizeof(dirname));
 258                 if (device_list_insert(dirname) != 0)
 259                         continue;
 260
 261                 /* look for partitions */
 262                 scan_subdir(dirname);
 263         }
 264
 265         closedir(dir);
 266 }
 267
 268 static void scan_class(void)
 269 {
 270         char base[PATH_SIZE];
 271         DIR *dir;
 272         struct dirent *dent;
 273
 274         strlcpy(base, "/sys/class", sizeof(base));
 275
 276         dir = opendir(base);
 277         if (dir == NULL)
 278                 return;
 279
 280         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 281                 char dirname[PATH_SIZE];
 282
 283                 if (dent->d_name[0] == '.')
 284                         continue;
 285
 286                 strlcpy(dirname, base, sizeof(dirname));
 287                 strlcat(dirname, "/", sizeof(dirname));
 288                 strlcat(dirname, dent->d_name, sizeof(dirname));
 289
 290                 scan_subdir(dirname);
 291         }
 292
 293         closedir(dir);
 294 }
 295
 296 int main(int argc, char *argv[], char *envp[])
 297 {
 298         struct stat statbuf;
 299         int option;
 300
 301         openlog("udevtrigger", LOG_PID | LOG_CONS, LOG_DAEMON);
 302
 303         while (1) {
 304                 option = getopt(argc, argv, "vnh");
 305                 if (option == -1)
 306                         break;
 307
 308                 switch (option) {
 309                 case 'v':
 310                         verbose = 1;
 311                         break;
 312                 case 'n':
 313                         dry_run = 1;
 314                         break;
 315                 case 'h':
 316                         printf("Usage: udevtrigger OPTIONS\n"
 317                                "  -v                     print the list of devices while running\n"
 318                                "  -n                     do not actually trigger the events\n"
 319                                "  -h                     print this text\n"
 320                                "\n");
 321                         goto exit;
 322                 default:
 323                         goto exit;
 324                 }
 325         }
 326
 327
 328         /* if we have /sys/subsystem, forget all the old stuff */
 329         scan_subsystem("bus");
 330         scan_class();
 331
 332         /* scan "block" if it isn't a "class" */
 333         if (stat("/sys/class/block", &statbuf) != 0)
 334                 scan_block();
 335
 336 exit:
 337
 338         closelog();
 339         return 0;
 340 }