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