udev/udev_db.c

   1 /*
   2  * Copyright (C) 2003 Greg Kroah-Hartman <greg@kroah.com>
   3  * Copyright (C) 2004-2005 Kay Sievers <kay.sievers@vrfy.org>
   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
  21 #include <stdlib.h>
  22 #include <stdio.h>
  23 #include <string.h>
  24 #include <stddef.h>
  25 #include <unistd.h>
  26 #include <fcntl.h>
  27 #include <string.h>
  28 #include <errno.h>
  29 #include <dirent.h>
  30 #include <sys/stat.h>
  31 #include <sys/types.h>
  32
  33 #include "udev.h"
  34 #include "udev_selinux.h"
  35
  36
  37 static size_t devpath_to_db_path(const char *devpath, char *filename, size_t len)
  38 {
  39         size_t start;
  40
  41         /* translate to location of db file */
  42         strlcpy(filename, udev_root, len);
  43         start = strlcat(filename, "/.udev/db/", len);
  44         strlcat(filename, devpath, len);
  45         return path_encode(&filename[start], len - start);
  46 }
  47
  48 /* reverse mapping from the device file name to the devpath */
  49 static int name_index(const char *devpath, const char *name, int add)
  50 {
  51         char device[PATH_SIZE];
  52         char filename[PATH_SIZE * 2];
  53         size_t start;
  54         int fd;
  55
  56         /* directory with device name */
  57         strlcpy(filename, udev_root, sizeof(filename));
  58         start = strlcat(filename, "/.udev/names/", sizeof(filename));
  59         strlcat(filename, name, sizeof(filename));
  60         path_encode(&filename[start], sizeof(filename) - start);
  61         /* entry with the devpath */
  62         strlcpy(device, devpath, sizeof(device));
  63         path_encode(device, sizeof(device));
  64         strlcat(filename, "/", sizeof(filename));
  65         strlcat(filename, device, sizeof(filename));
  66
  67         if (add) {
  68                 info("creating index: '%s'\n", filename);
  69                 create_path(filename);
  70                 fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
  71                 if (fd > 0)
  72                         close(fd);
  73         } else {
  74                 info("removing index: '%s'\n", filename);
  75                 unlink(filename);
  76                 delete_path(filename);
  77         }
  78         return 0;
  79 }
  80
  81 int udev_db_get_devices_by_name(const char *name, struct list_head *name_list)
  82 {
  83         char dirname[PATH_MAX];
  84         size_t start;
  85         DIR *dir;
  86         int rc = 0;
  87
  88         strlcpy(dirname, udev_root, sizeof(dirname));
  89         start = strlcat(dirname, "/.udev/names/", sizeof(dirname));
  90         strlcat(dirname, name, sizeof(dirname));
  91         path_encode(&dirname[start], sizeof(dirname) - start);
  92
  93         dir = opendir(dirname);
  94         if (dir == NULL) {
  95                 info("no index directory '%s': %s\n", dirname, strerror(errno));
  96                 rc = -1;
  97                 goto out;
  98         }
  99
 100         info("found index directory '%s'\n", dirname);
 101         while (1) {
 102                 struct dirent *ent;
 103                 char device[PATH_SIZE];
 104
 105                 ent = readdir(dir);
 106                 if (ent == NULL || ent->d_name[0] == '\0')
 107                         break;
 108                 if (ent->d_name[0] == '.')
 109                         continue;
 110
 111                 strlcpy(device, ent->d_name, sizeof(device));
 112                 path_decode(device);
 113                 name_list_add(name_list, device, 0);
 114                 rc++;
 115         }
 116         closedir(dir);
 117 out:
 118         return rc;
 119 }
 120
 121 int udev_db_rename(const char *devpath_old, const char *devpath)
 122 {
 123         char filename[PATH_SIZE];
 124         char filename_old[PATH_SIZE];
 125
 126         devpath_to_db_path(devpath_old, filename_old, sizeof(filename_old));
 127         devpath_to_db_path(devpath, filename, sizeof(filename));
 128         return rename(filename_old, filename);
 129 }
 130
 131 int udev_db_add_device(struct udevice *udev)
 132 {
 133         char filename[PATH_SIZE];
 134
 135         if (udev->test_run)
 136                 return 0;
 137
 138         devpath_to_db_path(udev->dev->devpath, filename, sizeof(filename));
 139         create_path(filename);
 140         unlink(filename);
 141
 142         /*
 143          * don't waste tmpfs memory pages, if we don't have any data to store
 144          * create fake db-file; store the node-name in a symlink target
 145          */
 146         if (list_empty(&udev->symlink_list) && list_empty(&udev->env_list) &&
 147             !udev->partitions && !udev->ignore_remove) {
 148                 int ret;
 149                 dbg("nothing interesting to store, create symlink\n");
 150                 selinux_setfscreatecon(filename, NULL, S_IFLNK);
 151                 ret = symlink(udev->name, filename);
 152                 selinux_resetfscreatecon();
 153                 if (ret != 0) {
 154                         err("unable to create db link '%s': %s\n", filename, strerror(errno));
 155                         return -1;
 156                 }
 157         } else {
 158                 FILE *f;
 159                 struct name_entry *name_loop;
 160
 161                 f = fopen(filename, "w");
 162                 if (f == NULL) {
 163                         err("unable to create db file '%s': %s\n", filename, strerror(errno));
 164                         return -1;
 165                 }
 166                 dbg("storing data for device '%s' in '%s'\n", udev->dev->devpath, filename);
 167
 168                 fprintf(f, "N:%s\n", udev->name);
 169                 list_for_each_entry(name_loop, &udev->symlink_list, node) {
 170                         fprintf(f, "S:%s\n", name_loop->name);
 171                         /* add symlink-name to index */
 172                         name_index(udev->dev->devpath, name_loop->name, 1);
 173                 }
 174                 fprintf(f, "M:%u:%u\n", major(udev->devt), minor(udev->devt));
 175                 if (udev->link_priority != 0)
 176                         fprintf(f, "L:%u\n", udev->link_priority);
 177                 if (udev->event_timeout >= 0)
 178                         fprintf(f, "T:%u\n", udev->event_timeout);
 179                 if (udev->partitions != 0)
 180                         fprintf(f, "A:%u\n", udev->partitions);
 181                 if (udev->ignore_remove)
 182                         fprintf(f, "R:%u\n", udev->ignore_remove);
 183                 list_for_each_entry(name_loop, &udev->env_list, node)
 184                         fprintf(f, "E:%s\n", name_loop->name);
 185                 fclose(f);
 186         }
 187
 188         /* add name to index */
 189         name_index(udev->dev->devpath, udev->name, 1);
 190
 191         return 0;
 192 }
 193
 194 int udev_db_get_device(struct udevice *udev, const char *devpath)
 195 {
 196         struct stat stats;
 197         char filename[PATH_SIZE];
 198         char line[PATH_SIZE];
 199         unsigned int maj, min;
 200         char *bufline;
 201         char *buf;
 202         size_t bufsize;
 203         size_t cur;
 204         size_t count;
 205
 206         sysfs_device_set_values(udev->dev, devpath, NULL, NULL);
 207         devpath_to_db_path(devpath, filename, sizeof(filename));
 208
 209         if (lstat(filename, &stats) != 0) {
 210                 info("no db file to read %s: %s\n", filename, strerror(errno));
 211                 return -1;
 212         }
 213         if ((stats.st_mode & S_IFMT) == S_IFLNK) {
 214                 char target[NAME_SIZE];
 215                 int target_len;
 216
 217                 info("found a symlink as db file\n");
 218                 target_len = readlink(filename, target, sizeof(target));
 219                 if (target_len > 0)
 220                         target[target_len] = '\0';
 221                 else {
 222                         info("error reading db link %s: %s\n", filename, strerror(errno));
 223                         return -1;
 224                 }
 225                 dbg("db link points to '%s'\n", target);
 226                 strlcpy(udev->name, target, sizeof(udev->name));
 227                 return 0;
 228         }
 229
 230         if (file_map(filename, &buf, &bufsize) != 0) {
 231                 info("error reading db file %s: %s\n", filename, strerror(errno));
 232                 return -1;
 233         }
 234
 235         cur = 0;
 236         while (cur < bufsize) {
 237                 count = buf_get_line(buf, bufsize, cur);
 238                 bufline = &buf[cur];
 239                 cur += count+1;
 240
 241                 if (count > sizeof(line))
 242                         count = sizeof(line);
 243                 memcpy(line, &bufline[2], count-2);
 244                 line[count-2] = '\0';
 245
 246                 switch(bufline[0]) {
 247                 case 'N':
 248                         strlcpy(udev->name, line, sizeof(udev->name));
 249                         break;
 250                 case 'M':
 251                         sscanf(line, "%u:%u", &maj, &min);
 252                         udev->devt = makedev(maj, min);
 253                         break;
 254                 case 'S':
 255                         name_list_add(&udev->symlink_list, line, 0);
 256                         break;
 257                 case 'L':
 258                         udev->link_priority = atoi(line);
 259                         break;
 260                 case 'T':
 261                         udev->event_timeout = atoi(line);
 262                         break;
 263                 case 'A':
 264                         udev->partitions = atoi(line);
 265                         break;
 266                 case 'R':
 267                         udev->ignore_remove = atoi(line);
 268                         break;
 269                 case 'E':
 270                         name_list_add(&udev->env_list, line, 0);
 271                         break;
 272                 }
 273         }
 274         file_unmap(buf, bufsize);
 275
 276         if (udev->name[0] == '\0')
 277                 return -1;
 278
 279         return 0;
 280 }
 281
 282 int udev_db_delete_device(struct udevice *udev)
 283 {
 284         char filename[PATH_SIZE];
 285         struct name_entry *name_loop;
 286
 287         if (udev->test_run)
 288                 return 0;
 289
 290         devpath_to_db_path(udev->dev->devpath, filename, sizeof(filename));
 291         unlink(filename);
 292
 293         name_index(udev->dev->devpath, udev->name, 0);
 294         list_for_each_entry(name_loop, &udev->symlink_list, node)
 295                 name_index(udev->dev->devpath, name_loop->name, 0);
 296
 297         return 0;
 298 }
 299
 300 int udev_db_get_all_entries(struct list_head *name_list)
 301 {
 302         char dbpath[PATH_MAX];
 303         DIR *dir;
 304
 305         strlcpy(dbpath, udev_root, sizeof(dbpath));
 306         strlcat(dbpath, "/.udev/db", sizeof(dbpath));
 307         dir = opendir(dbpath);
 308         if (dir == NULL) {
 309                 info("no udev_db available '%s': %s\n", dbpath, strerror(errno));
 310                 return -1;
 311         }
 312
 313         while (1) {
 314                 struct dirent *ent;
 315                 char device[PATH_SIZE];
 316
 317                 ent = readdir(dir);
 318                 if (ent == NULL || ent->d_name[0] == '\0')
 319                         break;
 320                 if (ent->d_name[0] == '.')
 321                         continue;
 322
 323                 strlcpy(device, ent->d_name, sizeof(device));
 324                 path_decode(device);
 325                 name_list_add(name_list, device, 1);
 326                 dbg("added '%s'\n", device);
 327         }
 328
 329         closedir(dir);
 330         return 0;
 331 }