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
  36 static size_t devpath_to_db_path(const char *devpath, char *filename, size_t len)
  37 {
  38         size_t start;
  39
  40         /* add location of db files */
  41         strlcpy(filename, udev_root, len);
  42         start = strlcat(filename, "/"DB_DIR"/", len);
  43         strlcat(filename, devpath, len);
  44         return path_encode(&filename[start], len - start);
  45 }
  46
  47 /* reverse mapping from the device file name to the devpath */
  48 static int name_index(const char *devpath, const char *name, int add)
  49 {
  50         char device[PATH_SIZE];
  51         char filename[PATH_SIZE * 2];
  52         size_t start;
  53         int fd;
  54
  55         /* directory with device name */
  56         strlcpy(filename, udev_root, sizeof(filename));
  57         start = strlcat(filename, "/"DB_NAME_INDEX_DIR"/", sizeof(filename));
  58         strlcat(filename, name, sizeof(filename));
  59         path_encode(&filename[start], sizeof(filename) - start);
  60         /* entry with the devpath */
  61         strlcpy(device, devpath, sizeof(device));
  62         path_encode(device, sizeof(device));
  63         strlcat(filename, "/", sizeof(filename));
  64         strlcat(filename, device, sizeof(filename));
  65
  66         if (add) {
  67                 info("creating index: '%s'", filename);
  68                 create_path(filename);
  69                 fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
  70                 if (fd > 0)
  71                         close(fd);
  72         } else {
  73                 info("removing index: '%s'", filename);
  74                 unlink(filename);
  75                 delete_path(filename);
  76         }
  77         return 0;
  78 }
  79
  80 int udev_db_add_device(struct udevice *udev)
  81 {
  82         char filename[PATH_SIZE];
  83
  84         if (udev->test_run)
  85                 return 0;
  86
  87         devpath_to_db_path(udev->dev->devpath, filename, sizeof(filename));
  88         create_path(filename);
  89         unlink(filename);
  90
  91         /*
  92          * don't waste tmpfs memory pages, if we don't have any data to store
  93          * create fake db-file; store the node-name in a symlink target
  94          */
  95         if (list_empty(&udev->symlink_list) && list_empty(&udev->env_list) &&
  96             !udev->partitions && !udev->ignore_remove) {
  97                 dbg("nothing interesting to store, create symlink");
  98                 if (symlink(udev->name, filename) != 0) {
  99                         err("unable to create db link '%s': %s", filename, strerror(errno));
 100                         return -1;
 101                 }
 102         } else {
 103                 FILE *f;
 104                 struct name_entry *name_loop;
 105
 106                 f = fopen(filename, "w");
 107                 if (f == NULL) {
 108                         err("unable to create db file '%s': %s", filename, strerror(errno));
 109                         return -1;
 110                 }
 111                 dbg("storing data for device '%s' in '%s'", udev->dev->devpath, filename);
 112
 113                 fprintf(f, "N:%s\n", udev->name);
 114                 list_for_each_entry(name_loop, &udev->symlink_list, node) {
 115                         fprintf(f, "S:%s\n", name_loop->name);
 116                         /* add symlink-name to index */
 117                         name_index(udev->dev->devpath, name_loop->name, 1);
 118                 }
 119                 fprintf(f, "M:%u:%u\n", major(udev->devt), minor(udev->devt));
 120                 if (udev->link_priority)
 121                         fprintf(f, "L:%u\n", udev->link_priority);
 122                 if (udev->partitions)
 123                         fprintf(f, "A:%u\n", udev->partitions);
 124                 if (udev->ignore_remove)
 125                         fprintf(f, "R:%u\n", udev->ignore_remove);
 126                 list_for_each_entry(name_loop, &udev->env_list, node)
 127                         fprintf(f, "E:%s\n", name_loop->name);
 128                 fclose(f);
 129         }
 130
 131         /* add name to index */
 132         name_index(udev->dev->devpath, udev->name, 1);
 133
 134         return 0;
 135 }
 136
 137 int udev_db_get_device(struct udevice *udev, const char *devpath)
 138 {
 139         struct stat stats;
 140         char filename[PATH_SIZE];
 141         char line[PATH_SIZE];
 142         unsigned int maj, min;
 143         char *bufline;
 144         char *buf;
 145         size_t bufsize;
 146         size_t cur;
 147         size_t count;
 148
 149         strlcpy(udev->dev->devpath, devpath, sizeof(udev->dev->devpath));
 150         devpath_to_db_path(devpath, filename, sizeof(filename));
 151
 152         if (lstat(filename, &stats) != 0) {
 153                 info("no db file to read %s: %s", filename, strerror(errno));
 154                 return -1;
 155         }
 156         if ((stats.st_mode & S_IFMT) == S_IFLNK) {
 157                 char target[NAME_SIZE];
 158                 int target_len;
 159
 160                 info("found a symlink as db file");
 161                 target_len = readlink(filename, target, sizeof(target));
 162                 if (target_len > 0)
 163                         target[target_len] = '\0';
 164                 else {
 165                         info("error reading db link %s: %s", filename, strerror(errno));
 166                         return -1;
 167                 }
 168                 dbg("db link points to '%s'", target);
 169                 strlcpy(udev->name, target, sizeof(udev->name));
 170                 return 0;
 171         }
 172
 173         if (file_map(filename, &buf, &bufsize) != 0) {
 174                 info("error reading db file %s: %s", filename, strerror(errno));
 175                 return -1;
 176         }
 177
 178         cur = 0;
 179         while (cur < bufsize) {
 180                 count = buf_get_line(buf, bufsize, cur);
 181                 bufline = &buf[cur];
 182                 cur += count+1;
 183
 184                 switch(bufline[0]) {
 185                 case 'N':
 186                         if (count > sizeof(udev->name))
 187                                 count = sizeof(udev->name);
 188                         memcpy(udev->name, &bufline[2], count-2);
 189                         udev->name[count-2] = '\0';
 190                         break;
 191                 case 'M':
 192                         if (count > sizeof(line))
 193                                 count = sizeof(line);
 194                         memcpy(line, &bufline[2], count-2);
 195                         line[count-2] = '\0';
 196                         sscanf(line, "%u:%u", &maj, &min);
 197                         udev->devt = makedev(maj, min);
 198                         break;
 199                 case 'S':
 200                         if (count > sizeof(line))
 201                                 count =  sizeof(line);
 202                         memcpy(line, &bufline[2], count-2);
 203                         line[count-2] = '\0';
 204                         name_list_add(&udev->symlink_list, line, 0);
 205                         break;
 206                 case 'L':
 207                         if (count > sizeof(line))
 208                                 count =  sizeof(line);
 209                         memcpy(line, &bufline[2], count-2);
 210                         line[count-2] = '\0';
 211                         udev->link_priority = atoi(line);
 212                         break;
 213                 case 'A':
 214                         if (count > sizeof(line))
 215                                 count =  sizeof(line);
 216                         memcpy(line, &bufline[2], count-2);
 217                         line[count-2] = '\0';
 218                         udev->partitions = atoi(line);
 219                         break;
 220                 case 'R':
 221                         if (count > sizeof(line))
 222                                 count =  sizeof(line);
 223                         memcpy(line, &bufline[2], count-2);
 224                         line[count-2] = '\0';
 225                         udev->ignore_remove = atoi(line);
 226                         break;
 227                 case 'E':
 228                         if (count > sizeof(line))
 229                                 count =  sizeof(line);
 230                         memcpy(line, &bufline[2], count-2);
 231                         line[count-2] = '\0';
 232                         name_list_add(&udev->env_list, line, 0);
 233                         break;
 234                 }
 235         }
 236         file_unmap(buf, bufsize);
 237
 238         if (udev->name[0] == '\0')
 239                 return -1;
 240
 241         return 0;
 242 }
 243
 244 int udev_db_delete_device(struct udevice *udev)
 245 {
 246         char filename[PATH_SIZE];
 247         struct name_entry *name_loop;
 248
 249         devpath_to_db_path(udev->dev->devpath, filename, sizeof(filename));
 250         unlink(filename);
 251
 252         name_index(udev->dev->devpath, udev->name, 0);
 253         list_for_each_entry(name_loop, &udev->symlink_list, node)
 254                 name_index(udev->dev->devpath, name_loop->name, 0);
 255
 256         return 0;
 257 }
 258
 259 int udev_db_lookup_name(const char *name, char *devpath, size_t len)
 260 {
 261         char dirname[PATH_MAX];
 262         size_t start;
 263         DIR *dir;
 264         int found = 0;
 265
 266         strlcpy(dirname, udev_root, sizeof(dirname));
 267         start = strlcat(dirname, "/"DB_NAME_INDEX_DIR"/", sizeof(dirname));
 268         strlcat(dirname, name, sizeof(dirname));
 269         path_encode(&dirname[start], sizeof(dirname) - start);
 270
 271         dir = opendir(dirname);
 272         if (dir == NULL) {
 273                 info("no index directory '%s': %s", dirname, strerror(errno));
 274                 return -1;
 275         }
 276
 277         info("found index directory '%s'", dirname);
 278         while (!found) {
 279                 struct dirent *ent;
 280                 char device[PATH_SIZE];
 281                 struct udevice *udev;
 282
 283                 ent = readdir(dir);
 284                 if (ent == NULL || ent->d_name[0] == '\0')
 285                         break;
 286                 if (ent->d_name[0] == '.')
 287                         continue;
 288
 289                 strlcpy(device, ent->d_name, sizeof(device));
 290                 path_decode(device);
 291                 udev = udev_device_init();
 292                 if (udev == NULL)
 293                         break;
 294                 if (udev_db_get_device(udev, device) == 0) {
 295                         char filename[PATH_SIZE];
 296                         struct stat statbuf;
 297
 298                         info("found db entry '%s'", device);
 299                         strlcpy(filename, udev_root, sizeof(filename));
 300                         strlcat(filename, "/", sizeof(filename));
 301                         strlcat(filename, name, sizeof(filename));
 302                         /* make sure device entry matches dev_t */
 303                         if (stat(filename, &statbuf) == 0) {
 304                                 if (statbuf.st_rdev == udev->devt) {
 305                                         info("node '%s' matches dev_t", udev->name);
 306                                         strlcpy(devpath, device, len);
 307                                         found = 1;
 308                                 }
 309                         }
 310                 }
 311                 udev_device_cleanup(udev);
 312         }
 313
 314         closedir(dir);
 315         if (found)
 316                 return 0;
 317         else
 318                 return -1;
 319 }
 320
 321 int udev_db_get_all_entries(struct list_head *name_list)
 322 {
 323         char dbpath[PATH_MAX];
 324         DIR *dir;
 325
 326         strlcpy(dbpath, udev_root, sizeof(dbpath));
 327         strlcat(dbpath, "/"DB_DIR, sizeof(dbpath));
 328         dir = opendir(dbpath);
 329         if (dir == NULL) {
 330                 info("no udev_db available '%s': %s", dbpath, strerror(errno));
 331                 return -1;
 332         }
 333
 334         while (1) {
 335                 struct dirent *ent;
 336                 char device[PATH_SIZE];
 337
 338                 ent = readdir(dir);
 339                 if (ent == NULL || ent->d_name[0] == '\0')
 340                         break;
 341                 if (ent->d_name[0] == '.')
 342                         continue;
 343
 344                 strlcpy(device, ent->d_name, sizeof(device));
 345                 path_decode(device);
 346                 name_list_add(name_list, device, 1);
 347                 dbg("added '%s'", device);
 348         }
 349
 350         closedir(dir);
 351         return 0;
 352 }