udev/lib/libudev-enumerate.c

   1 /*
   2  * libudev - interface to udev device information
   3  *
   4  * Copyright (C) 2008 Kay Sievers <kay.sievers@vrfy.org>
   5  *
   6  * This program is free software: you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation, either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <stddef.h>
  23 #include <unistd.h>
  24 #include <errno.h>
  25 #include <string.h>
  26 #include <dirent.h>
  27 #include <fnmatch.h>
  28 #include <sys/stat.h>
  29
  30 #include "libudev.h"
  31 #include "libudev-private.h"
  32
  33 static int devices_sort(struct udev_enumerate *udev_enumerate);
  34
  35 struct udev_enumerate {
  36         struct udev *udev;
  37         int refcount;
  38         struct udev_list_node sysattr_match_list;
  39         struct udev_list_node sysattr_nomatch_list;
  40         struct udev_list_node subsystem_match_list;
  41         struct udev_list_node subsystem_nomatch_list;
  42         struct udev_list_node devices_list;
  43         int devices_sorted;
  44 };
  45
  46 /**
  47  * udev_enumerate_new:
  48  * @udev: udev library context
  49  *
  50  * Returns: an enumeration context
  51  **/
  52 struct udev_enumerate *udev_enumerate_new(struct udev *udev)
  53 {
  54         struct udev_enumerate *udev_enumerate;
  55
  56         udev_enumerate = calloc(1, sizeof(struct udev_enumerate));
  57         if (udev_enumerate == NULL)
  58                 return NULL;
  59         udev_enumerate->refcount = 1;
  60         udev_enumerate->udev = udev;
  61         udev_list_init(&udev_enumerate->devices_list);
  62         udev_list_init(&udev_enumerate->sysattr_match_list);
  63         udev_list_init(&udev_enumerate->sysattr_nomatch_list);
  64         udev_list_init(&udev_enumerate->subsystem_match_list);
  65         udev_list_init(&udev_enumerate->subsystem_nomatch_list);
  66         return udev_enumerate;
  67 }
  68
  69 struct udev_enumerate *udev_enumerate_ref(struct udev_enumerate *udev_enumerate)
  70 {
  71         if (udev_enumerate == NULL)
  72                 return NULL;
  73         udev_enumerate->refcount++;
  74         return udev_enumerate;
  75 }
  76
  77 void udev_enumerate_unref(struct udev_enumerate *udev_enumerate)
  78 {
  79         if (udev_enumerate == NULL)
  80                 return;
  81         udev_enumerate->refcount--;
  82         if (udev_enumerate->refcount > 0)
  83                 return;
  84         udev_list_cleanup_entries(udev_enumerate->udev, &udev_enumerate->devices_list);
  85         udev_list_cleanup_entries(udev_enumerate->udev, &udev_enumerate->sysattr_match_list);
  86         udev_list_cleanup_entries(udev_enumerate->udev, &udev_enumerate->sysattr_nomatch_list);
  87         udev_list_cleanup_entries(udev_enumerate->udev, &udev_enumerate->subsystem_match_list);
  88         udev_list_cleanup_entries(udev_enumerate->udev, &udev_enumerate->subsystem_nomatch_list);
  89         free(udev_enumerate);
  90 }
  91
  92 struct udev *udev_enumerate_get_udev(struct udev_enumerate *udev_enumerate)
  93 {
  94         if (udev_enumerate == NULL)
  95                 return NULL;
  96         return udev_enumerate->udev;
  97 }
  98
  99 struct udev_list_entry *udev_enumerate_get_list_entry(struct udev_enumerate *udev_enumerate)
 100 {
 101         if (udev_enumerate == NULL)
 102                 return NULL;
 103         if (!udev_enumerate->devices_sorted)
 104                 devices_sort(udev_enumerate);
 105         return udev_list_get_entry(&udev_enumerate->devices_list);
 106 }
 107
 108 int udev_enumerate_add_match_subsystem(struct udev_enumerate *udev_enumerate, const char *subsystem)
 109 {
 110         if (udev_enumerate == NULL)
 111                 return -EINVAL;
 112         if (subsystem == NULL)
 113                 return 0;
 114         if (udev_list_entry_add(udev_enumerate_get_udev(udev_enumerate),
 115                                 &udev_enumerate->subsystem_match_list, subsystem, NULL, 1, 0) == NULL)
 116                 return -ENOMEM;
 117         return 0;
 118 }
 119
 120 int udev_enumerate_add_nomatch_subsystem(struct udev_enumerate *udev_enumerate, const char *subsystem)
 121 {
 122         if (udev_enumerate == NULL)
 123                 return -EINVAL;
 124         if (subsystem == NULL)
 125                 return 0;
 126         if (udev_list_entry_add(udev_enumerate_get_udev(udev_enumerate),
 127                                 &udev_enumerate->subsystem_nomatch_list, subsystem, NULL, 1, 0) == NULL)
 128                 return -ENOMEM;
 129         return 0;
 130 }
 131
 132 int udev_enumerate_add_match_sysattr(struct udev_enumerate *udev_enumerate, const char *sysattr, const char *value)
 133 {
 134         if (udev_enumerate == NULL)
 135                 return -EINVAL;
 136         if (sysattr == NULL)
 137                 return 0;
 138         if (udev_list_entry_add(udev_enumerate_get_udev(udev_enumerate),
 139                            &udev_enumerate->sysattr_match_list, sysattr, value, 1, 0) == NULL)
 140                 return -ENOMEM;
 141         return 0;
 142 }
 143
 144 int udev_enumerate_add_nomatch_sysattr(struct udev_enumerate *udev_enumerate, const char *sysattr, const char *value)
 145 {
 146         if (udev_enumerate == NULL)
 147                 return -EINVAL;
 148         if (sysattr == NULL)
 149                 return 0;
 150         if (udev_list_entry_add(udev_enumerate_get_udev(udev_enumerate),
 151                            &udev_enumerate->sysattr_nomatch_list, sysattr, value, 1, 0) == NULL)
 152                 return -ENOMEM;
 153         return 0;
 154 }
 155
 156 static int match_sysattr_value(struct udev *udev, const char *syspath, const char *sysattr, const char *match_val)
 157 {
 158         struct udev_device *device;
 159         const char *val = NULL;
 160         int match = 0;
 161
 162         device = udev_device_new_from_syspath(udev, syspath);
 163         if (device == NULL)
 164                 return -EINVAL;
 165         val = udev_device_get_sysattr_value(device, sysattr);
 166         if (val == NULL)
 167                 goto exit;
 168         if (match_val == NULL) {
 169                 match = 1;
 170                 goto exit;
 171         }
 172         if (fnmatch(match_val, val, 0) == 0) {
 173                 match = 1;
 174                 goto exit;
 175         }
 176 exit:
 177         udev_device_unref(device);
 178         return match;
 179 }
 180
 181 static int match_sysattr(struct udev_enumerate *udev_enumerate, const char *syspath)
 182 {
 183         struct udev *udev = udev_enumerate_get_udev(udev_enumerate);
 184         struct udev_list_entry *list_entry;
 185
 186         /* skip list */
 187         udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->sysattr_nomatch_list)) {
 188                 if (match_sysattr_value(udev, syspath,
 189                                      udev_list_entry_get_name(list_entry),
 190                                      udev_list_entry_get_value(list_entry)))
 191                         return 0;
 192         }
 193         /* include list */
 194         if (udev_list_get_entry(&udev_enumerate->sysattr_match_list) != NULL) {
 195                 udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->sysattr_match_list)) {
 196                         /* anything that does not match, will make it FALSE */
 197                         if (!match_sysattr_value(udev, syspath,
 198                                               udev_list_entry_get_name(list_entry),
 199                                               udev_list_entry_get_value(list_entry)))
 200                                 return 0;
 201                 }
 202                 return 1;
 203         }
 204         return 1;
 205 }
 206
 207 static int scan_dir_and_add_devices(struct udev_enumerate *udev_enumerate,
 208                                     const char *basedir, const char *subdir1, const char *subdir2)
 209 {
 210         struct udev *udev = udev_enumerate_get_udev(udev_enumerate);
 211         char path[UTIL_PATH_SIZE];
 212         DIR *dir;
 213         struct dirent *dent;
 214
 215         util_strlcpy(path, udev_get_sys_path(udev), sizeof(path));
 216         util_strlcat(path, "/", sizeof(path));
 217         util_strlcat(path, basedir, sizeof(path));
 218         if (subdir1 != NULL) {
 219                 util_strlcat(path, "/", sizeof(path));
 220                 util_strlcat(path, subdir1, sizeof(path));
 221         }
 222         if (subdir2 != NULL) {
 223                 util_strlcat(path, "/", sizeof(path));
 224                 util_strlcat(path, subdir2, sizeof(path));
 225         }
 226         dir = opendir(path);
 227         if (dir == NULL)
 228                 return -1;
 229         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 230                 char syspath[UTIL_PATH_SIZE];
 231                 char filename[UTIL_PATH_SIZE];
 232                 struct stat statbuf;
 233
 234                 if (dent->d_name[0] == '.')
 235                         continue;
 236                 util_strlcpy(syspath, path, sizeof(syspath));
 237                 util_strlcat(syspath, "/", sizeof(syspath));
 238                 util_strlcat(syspath, dent->d_name, sizeof(syspath));
 239                 if (lstat(syspath, &statbuf) != 0)
 240                         continue;
 241                 if (S_ISREG(statbuf.st_mode))
 242                         continue;
 243                 if (S_ISLNK(statbuf.st_mode))
 244                         util_resolve_sys_link(udev, syspath, sizeof(syspath));
 245                 util_strlcpy(filename, syspath, sizeof(filename));
 246                 util_strlcat(filename, "/uevent", sizeof(filename));
 247                 if (stat(filename, &statbuf) != 0)
 248                         continue;
 249                 if (!match_sysattr(udev_enumerate, syspath))
 250                         continue;
 251                 udev_list_entry_add(udev, &udev_enumerate->devices_list, syspath, NULL, 1, 1);
 252         }
 253         closedir(dir);
 254         return 0;
 255 }
 256
 257 static int match_subsystem(struct udev_enumerate *udev_enumerate, const char *subsystem)
 258 {
 259         struct udev_list_entry *list_entry;
 260
 261         udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->subsystem_nomatch_list)) {
 262                 if (fnmatch(udev_list_entry_get_name(list_entry), subsystem, 0) == 0)
 263                         return 0;
 264         }
 265         if (udev_list_get_entry(&udev_enumerate->subsystem_match_list) != NULL) {
 266                 udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->subsystem_match_list)) {
 267                         if (fnmatch(udev_list_entry_get_name(list_entry), subsystem, 0) == 0)
 268                                 return 1;
 269                 }
 270                 return 0;
 271         }
 272         return 1;
 273 }
 274
 275 static int scan_dir(struct udev_enumerate *udev_enumerate, const char *basedir, const char *subdir, const char *subsystem)
 276 {
 277         struct udev *udev = udev_enumerate_get_udev(udev_enumerate);
 278
 279         char path[UTIL_PATH_SIZE];
 280         DIR *dir;
 281         struct dirent *dent;
 282
 283         util_strlcpy(path, udev_get_sys_path(udev), sizeof(path));
 284         util_strlcat(path, "/", sizeof(path));
 285         util_strlcat(path, basedir, sizeof(path));
 286         dir = opendir(path);
 287         if (dir == NULL)
 288                 return -1;
 289         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 290                 if (dent->d_name[0] == '.')
 291                         continue;
 292                 if (!match_subsystem(udev_enumerate, subsystem != NULL ? subsystem : dent->d_name))
 293                         continue;
 294                 scan_dir_and_add_devices(udev_enumerate, basedir, dent->d_name, subdir);
 295         }
 296         closedir(dir);
 297         return 0;
 298 }
 299
 300 static int devices_delay(struct udev *udev, const char *syspath)
 301 {
 302         static const char *delay_device_list[] = {
 303                 "/block/md",
 304                 "/block/dm-",
 305                 NULL
 306         };
 307         size_t len;
 308         int i;
 309
 310         len = strlen(udev_get_sys_path(udev));
 311         for (i = 0; delay_device_list[i] != NULL; i++) {
 312                 if (strstr(&syspath[len], delay_device_list[i]) != NULL) {
 313                         dbg(udev, "delaying: %s\n", syspath);
 314                         return 1;
 315                 }
 316         }
 317         return 0;
 318 }
 319
 320 /* sort delayed devices to the end of the list */
 321 static int devices_sort(struct udev_enumerate *udev_enumerate)
 322 {
 323         struct udev_list_entry *list_entry;
 324
 325         udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->devices_list)) {
 326                 if (devices_delay(udev_enumerate->udev, udev_list_entry_get_name(list_entry)))
 327                         udev_list_entry_move_to_end(list_entry);
 328         }
 329         udev_enumerate->devices_sorted = 1;
 330         return 0;
 331 }
 332
 333 int udev_enumerate_add_syspath(struct udev_enumerate *udev_enumerate, const char *syspath)
 334 {
 335         struct udev *udev = udev_enumerate_get_udev(udev_enumerate);
 336         struct udev_device *udev_device;
 337
 338         if (udev_enumerate == NULL)
 339                 return -EINVAL;
 340         if (syspath == NULL)
 341                 return 0;
 342         /* resolve to real syspath */
 343         udev_device = udev_device_new_from_syspath(udev_enumerate->udev, syspath);
 344         if (udev_device == NULL)
 345                 return -EINVAL;
 346         udev_list_entry_add(udev, &udev_enumerate->devices_list,
 347                             udev_device_get_syspath(udev_device), NULL, 1, 1);
 348         udev_device_unref(udev_device);
 349         return 0;
 350 }
 351
 352 /**
 353  * udev_enumerate_scan_devices:
 354  * @udev_enumerate: udev enumeration context
 355  *
 356  * Returns: a negative value on error.
 357  **/
 358 int udev_enumerate_scan_devices(struct udev_enumerate *udev_enumerate)
 359 {
 360         struct udev *udev = udev_enumerate_get_udev(udev_enumerate);
 361         char base[UTIL_PATH_SIZE];
 362         struct stat statbuf;
 363         struct udev_list_entry *list_entry;
 364
 365         if (udev_enumerate == NULL)
 366                 return -EINVAL;
 367         util_strlcpy(base, udev_get_sys_path(udev), sizeof(base));
 368         util_strlcat(base, "/subsystem", sizeof(base));
 369         if (stat(base, &statbuf) == 0) {
 370                 /* we have /subsystem/, forget all the old stuff */
 371                 dbg(udev, "searching '/subsystem/*/devices/*' dir\n");
 372                 scan_dir(udev_enumerate, "subsystem", "devices", NULL);
 373         } else {
 374                 dbg(udev, "searching '/bus/*/devices/*' dir\n");
 375                 scan_dir(udev_enumerate, "bus", "devices", NULL);
 376                 dbg(udev, "searching '/class/*' dir\n");
 377                 scan_dir(udev_enumerate, "class", NULL, NULL);
 378                 /* if block isn't a class, scan /block/ */
 379                 util_strlcpy(base, udev_get_sys_path(udev), sizeof(base));
 380                 util_strlcat(base, "/class/block", sizeof(base));
 381                 if (stat(base, &statbuf) != 0) {
 382                         if (match_subsystem(udev_enumerate, "block")) {
 383                                 dbg(udev, "searching '/block/*' dir\n");
 384                                 /* scan disks */
 385                                 scan_dir_and_add_devices(udev_enumerate, "block", NULL, NULL);
 386                                 /* scan partitions */
 387                                 dbg(udev, "searching '/block/*/*' dir\n");
 388                                 scan_dir(udev_enumerate, "block", NULL, "block");
 389                         }
 390                 }
 391         }
 392         /* sort delayed devices to the end of the list */
 393         udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->devices_list)) {
 394                 if (devices_delay(udev, udev_list_entry_get_name(list_entry)))
 395                         udev_list_entry_move_to_end(list_entry);
 396         }
 397         return 0;
 398 }
 399
 400 /**
 401  * udev_enumerate_scan_subsystems:
 402  * @udev_enumerate: udev enumeration context
 403  *
 404  * Returns: a negative value on error.
 405  **/
 406 int udev_enumerate_scan_subsystems(struct udev_enumerate *udev_enumerate)
 407 {
 408         struct udev *udev = udev_enumerate_get_udev(udev_enumerate);
 409         char base[UTIL_PATH_SIZE];
 410         struct stat statbuf;
 411         const char *subsysdir;
 412
 413         if (udev_enumerate == NULL)
 414                 return -EINVAL;
 415         util_strlcpy(base, udev_get_sys_path(udev), sizeof(base));
 416         util_strlcat(base, "/subsystem", sizeof(base));
 417         if (stat(base, &statbuf) == 0)
 418                 subsysdir = "subsystem";
 419         else
 420                 subsysdir = "bus";
 421         if (match_subsystem(udev_enumerate, "subsystem")) {
 422                 dbg(udev, "searching '%s/*' dir\n", subsysdir);
 423                 scan_dir_and_add_devices(udev_enumerate, subsysdir, NULL, NULL);
 424         }
 425         if (match_subsystem(udev_enumerate, "drivers")) {
 426                 dbg(udev, "searching '%s/*/drivers/*' dir\n", subsysdir);
 427                 scan_dir(udev_enumerate, subsysdir, "drivers", "drivers");
 428         }
 429         return 0;
 430 }