udev/udev_db.c

   1 /*
   2  * Copyright (C) 2003 Greg Kroah-Hartman <greg@kroah.com>
   3  * Copyright (C) 2004-2008 Kay Sievers <kay.sievers@vrfy.org>
   4  *
   5  * This program is free software: you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation, either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19 #include <stdlib.h>
  20 #include <stdio.h>
  21 #include <string.h>
  22 #include <stddef.h>
  23 #include <unistd.h>
  24 #include <fcntl.h>
  25 #include <string.h>
  26 #include <errno.h>
  27 #include <dirent.h>
  28 #include <sys/stat.h>
  29 #include <sys/types.h>
  30
  31 #include "udev.h"
  32
  33 static size_t devpath_to_db_path(struct udev *udev, const char *devpath, char *filename, size_t len)
  34 {
  35         size_t start;
  36
  37         /* translate to location of db file */
  38         util_strlcpy(filename, udev_get_dev_path(udev), len);
  39         start = util_strlcat(filename, "/.udev/db/", len);
  40         util_strlcat(filename, devpath, len);
  41         return util_path_encode(&filename[start], len - start);
  42 }
  43
  44 /* reverse mapping from the device file name to the devpath */
  45 static int name_index(struct udev *udev, const char *devpath, const char *name, int add)
  46 {
  47         char device[UTIL_PATH_SIZE];
  48         char filename[UTIL_PATH_SIZE * 2];
  49         size_t start;
  50         int fd;
  51
  52         /* directory with device name */
  53         util_strlcpy(filename, udev_get_dev_path(udev), sizeof(filename));
  54         start = util_strlcat(filename, "/.udev/names/", sizeof(filename));
  55         util_strlcat(filename, name, sizeof(filename));
  56         util_path_encode(&filename[start], sizeof(filename) - start);
  57         /* entry with the devpath */
  58         util_strlcpy(device, devpath, sizeof(device));
  59         util_path_encode(device, sizeof(device));
  60         util_strlcat(filename, "/", sizeof(filename));
  61         util_strlcat(filename, device, sizeof(filename));
  62
  63         if (add) {
  64                 info(udev, "creating index: '%s'\n", filename);
  65                 create_path(udev, filename);
  66                 fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
  67                 if (fd > 0)
  68                         close(fd);
  69         } else {
  70                 info(udev, "removing index: '%s'\n", filename);
  71                 unlink(filename);
  72                 delete_path(udev, filename);
  73         }
  74         return 0;
  75 }
  76
  77 int udev_db_get_devices_by_name(struct udev *udev, const char *name, struct list_head *name_list)
  78 {
  79         char dirname[PATH_MAX];
  80         size_t start;
  81         DIR *dir;
  82         int rc = 0;
  83
  84         util_strlcpy(dirname, udev_get_dev_path(udev), sizeof(dirname));
  85         start = util_strlcat(dirname, "/.udev/names/", sizeof(dirname));
  86         util_strlcat(dirname, name, sizeof(dirname));
  87         util_path_encode(&dirname[start], sizeof(dirname) - start);
  88
  89         dir = opendir(dirname);
  90         if (dir == NULL) {
  91                 info(udev, "no index directory '%s': %m\n", dirname);
  92                 rc = -1;
  93                 goto out;
  94         }
  95
  96         info(udev, "found index directory '%s'\n", dirname);
  97         while (1) {
  98                 struct dirent *ent;
  99                 char device[UTIL_PATH_SIZE];
 100
 101                 ent = readdir(dir);
 102                 if (ent == NULL || ent->d_name[0] == '\0')
 103                         break;
 104                 if (ent->d_name[0] == '.')
 105                         continue;
 106
 107                 util_strlcpy(device, ent->d_name, sizeof(device));
 108                 util_path_decode(device);
 109                 name_list_add(udev, name_list, device, 0);
 110                 rc++;
 111         }
 112         closedir(dir);
 113 out:
 114         return rc;
 115 }
 116
 117 int udev_db_rename(struct udev *udev, const char *devpath_old, const char *devpath)
 118 {
 119         char filename[UTIL_PATH_SIZE];
 120         char filename_old[UTIL_PATH_SIZE];
 121
 122         devpath_to_db_path(udev, devpath_old, filename_old, sizeof(filename_old));
 123         devpath_to_db_path(udev, devpath, filename, sizeof(filename));
 124         return rename(filename_old, filename);
 125 }
 126
 127 int udev_db_add_device(struct udevice *udevice)
 128 {
 129         char filename[UTIL_PATH_SIZE];
 130
 131         if (udevice->test_run)
 132                 return 0;
 133
 134         devpath_to_db_path(udevice->udev, udevice->dev->devpath, filename, sizeof(filename));
 135         create_path(udevice->udev, filename);
 136         unlink(filename);
 137
 138         /*
 139          * don't waste tmpfs memory pages, if we don't have any data to store
 140          * create fake db-file; store the node-name in a symlink target
 141          */
 142         if (list_empty(&udevice->symlink_list) && list_empty(&udevice->env_list) &&
 143             !udevice->partitions && !udevice->ignore_remove) {
 144                 int ret;
 145                 dbg(udevice->udev, "nothing interesting to store, create symlink\n");
 146                 udev_selinux_setfscreatecon(udevice->udev, filename, S_IFLNK);
 147                 ret = symlink(udevice->name, filename);
 148                 udev_selinux_resetfscreatecon(udevice->udev);
 149                 if (ret != 0) {
 150                         err(udevice->udev, "unable to create db link '%s': %m\n", filename);
 151                         return -1;
 152                 }
 153         } else {
 154                 FILE *f;
 155                 struct name_entry *name_loop;
 156
 157                 f = fopen(filename, "w");
 158                 if (f == NULL) {
 159                         err(udevice->udev, "unable to create db file '%s': %m\n", filename);
 160                         return -1;
 161                 }
 162                 dbg(udevice->udev, "storing data for device '%s' in '%s'\n", udevice->dev->devpath, filename);
 163
 164                 fprintf(f, "N:%s\n", udevice->name);
 165                 list_for_each_entry(name_loop, &udevice->symlink_list, node) {
 166                         fprintf(f, "S:%s\n", name_loop->name);
 167                         /* add symlink-name to index */
 168                         name_index(udevice->udev, udevice->dev->devpath, name_loop->name, 1);
 169                 }
 170                 fprintf(f, "M:%u:%u\n", major(udevice->devt), minor(udevice->devt));
 171                 if (udevice->link_priority != 0)
 172                         fprintf(f, "L:%u\n", udevice->link_priority);
 173                 if (udevice->event_timeout >= 0)
 174                         fprintf(f, "T:%u\n", udevice->event_timeout);
 175                 if (udevice->partitions != 0)
 176                         fprintf(f, "A:%u\n", udevice->partitions);
 177                 if (udevice->ignore_remove)
 178                         fprintf(f, "R:%u\n", udevice->ignore_remove);
 179                 list_for_each_entry(name_loop, &udevice->env_list, node)
 180                         fprintf(f, "E:%s\n", name_loop->name);
 181                 fclose(f);
 182         }
 183
 184         /* add name to index */
 185         name_index(udevice->udev, udevice->dev->devpath, udevice->name, 1);
 186
 187         return 0;
 188 }
 189
 190 int udev_db_get_device(struct udevice *udevice, const char *devpath)
 191 {
 192         struct stat stats;
 193         char filename[UTIL_PATH_SIZE];
 194         char line[UTIL_PATH_SIZE];
 195         unsigned int maj, min;
 196         char *bufline;
 197         char *buf;
 198         size_t bufsize;
 199         size_t cur;
 200         size_t count;
 201
 202         sysfs_device_set_values(udevice->udev, udevice->dev, devpath, NULL, NULL);
 203         devpath_to_db_path(udevice->udev, devpath, filename, sizeof(filename));
 204
 205         if (lstat(filename, &stats) != 0) {
 206                 info(udevice->udev, "no db file to read %s: %m\n", filename);
 207                 return -1;
 208         }
 209         if ((stats.st_mode & S_IFMT) == S_IFLNK) {
 210                 char target[UTIL_NAME_SIZE];
 211                 int target_len;
 212
 213                 info(udevice->udev, "found a symlink as db file\n");
 214                 target_len = readlink(filename, target, sizeof(target));
 215                 if (target_len > 0)
 216                         target[target_len] = '\0';
 217                 else {
 218                         info(udevice->udev, "error reading db link %s: %m\n", filename);
 219                         return -1;
 220                 }
 221                 dbg(udevice->udev, "db link points to '%s'\n", target);
 222                 util_strlcpy(udevice->name, target, sizeof(udevice->name));
 223                 return 0;
 224         }
 225
 226         if (file_map(filename, &buf, &bufsize) != 0) {
 227                 info(udevice->udev, "error reading db file %s: %m\n", filename);
 228                 return -1;
 229         }
 230
 231         cur = 0;
 232         while (cur < bufsize) {
 233                 count = buf_get_line(buf, bufsize, cur);
 234                 bufline = &buf[cur];
 235                 cur += count+1;
 236
 237                 if (count > sizeof(line))
 238                         count = sizeof(line);
 239                 memcpy(line, &bufline[2], count-2);
 240                 line[count-2] = '\0';
 241
 242                 switch(bufline[0]) {
 243                 case 'N':
 244                         util_strlcpy(udevice->name, line, sizeof(udevice->name));
 245                         break;
 246                 case 'M':
 247                         sscanf(line, "%u:%u", &maj, &min);
 248                         udevice->devt = makedev(maj, min);
 249                         break;
 250                 case 'S':
 251                         name_list_add(udevice->udev, &udevice->symlink_list, line, 0);
 252                         break;
 253                 case 'L':
 254                         udevice->link_priority = atoi(line);
 255                         break;
 256                 case 'T':
 257                         udevice->event_timeout = atoi(line);
 258                         break;
 259                 case 'A':
 260                         udevice->partitions = atoi(line);
 261                         break;
 262                 case 'R':
 263                         udevice->ignore_remove = atoi(line);
 264                         break;
 265                 case 'E':
 266                         name_list_add(udevice->udev, &udevice->env_list, line, 0);
 267                         break;
 268                 }
 269         }
 270         file_unmap(buf, bufsize);
 271
 272         if (udevice->name[0] == '\0')
 273                 return -1;
 274
 275         return 0;
 276 }
 277
 278 int udev_db_delete_device(struct udevice *udevice)
 279 {
 280         char filename[UTIL_PATH_SIZE];
 281         struct name_entry *name_loop;
 282
 283         if (udevice->test_run)
 284                 return 0;
 285
 286         devpath_to_db_path(udevice->udev, udevice->dev->devpath, filename, sizeof(filename));
 287         unlink(filename);
 288
 289         name_index(udevice->udev, udevice->dev->devpath, udevice->name, 0);
 290         list_for_each_entry(name_loop, &udevice->symlink_list, node)
 291                 name_index(udevice->udev, udevice->dev->devpath, name_loop->name, 0);
 292
 293         return 0;
 294 }