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