udev_add.c

   1 /*
   2  * udev-add.c
   3  *
   4  * Userspace devfs
   5  *
   6  * Copyright (C) 2003 Greg Kroah-Hartman <greg@kroah.com>
   7  *
   8  *
   9  *      This program is free software; you can redistribute it and/or modify it
  10  *      under the terms of the GNU General Public License as published by the
  11  *      Free Software Foundation version 2 of the License.
  12  *
  13  *      This program is distributed in the hope that it will be useful, but
  14  *      WITHOUT ANY WARRANTY; without even the implied warranty of
  15  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  *      General Public License for more details.
  17  *
  18  *      You should have received a copy of the GNU General Public License along
  19  *      with this program; if not, write to the Free Software Foundation, Inc.,
  20  *      675 Mass Ave, Cambridge, MA 02139, USA.
  21  *
  22  */
  23
  24 #include <stdlib.h>
  25 #include <string.h>
  26 #include <stdio.h>
  27 #include <fcntl.h>
  28 #include <unistd.h>
  29 #include <errno.h>
  30 #include <sys/stat.h>
  31 #include <sys/types.h>
  32 #include <grp.h>
  33 #include <net/if.h>
  34 #include <sys/socket.h>
  35 #include <sys/ioctl.h>
  36 #include <linux/sockios.h>
  37 #include <pwd.h>
  38
  39 #include "libsysfs/sysfs/libsysfs.h"
  40 #include "udev.h"
  41 #include "udev_utils.h"
  42 #include "udev_version.h"
  43 #include "logging.h"
  44 #include "namedev.h"
  45 #include "udev_db.h"
  46 #include "udev_selinux.h"
  47
  48 /*
  49  * the major/minor of a device is stored in a file called "dev"
  50  * The number is stored in decimal values in the format: M:m
  51  */
  52 static int get_major_minor(struct sysfs_class_device *class_dev, struct udevice *udev)
  53 {
  54         struct sysfs_attribute *attr = NULL;
  55
  56         attr = sysfs_get_classdev_attr(class_dev, "dev");
  57         if (attr == NULL)
  58                 goto error;
  59         dbg("dev='%s'", attr->value);
  60
  61         if (sscanf(attr->value, "%u:%u", &udev->major, &udev->minor) != 2)
  62                 goto error;
  63         dbg("found major=%d, minor=%d", udev->major, udev->minor);
  64
  65         return 0;
  66 error:
  67         return -1;
  68 }
  69
  70 int udev_make_node(struct udevice *udev, const char *file, int major, int minor, mode_t mode, uid_t uid, gid_t gid)
  71 {
  72         struct stat stats;
  73         int retval = 0;
  74
  75         if (stat(file, &stats) != 0)
  76                 goto create;
  77
  78         /* preserve node with already correct numbers, to not change the inode number */
  79         if (((stats.st_mode & S_IFMT) == S_IFBLK || (stats.st_mode & S_IFMT) == S_IFCHR) &&
  80             (stats.st_rdev == makedev(major, minor))) {
  81                 dbg("preserve file '%s', cause it has correct dev_t", file);
  82                 selinux_setfilecon(file, udev->kernel_name, stats.st_mode);
  83                 goto perms;
  84         }
  85
  86         if (unlink(file) != 0)
  87                 dbg("unlink(%s) failed with error '%s'", file, strerror(errno));
  88         else
  89                 dbg("already present file '%s' unlinked", file);
  90
  91 create:
  92         selinux_setfscreatecon(file, udev->kernel_name, mode);
  93         retval = mknod(file, mode, makedev(major, minor));
  94         if (retval != 0) {
  95                 dbg("mknod(%s, %#o, %u, %u) failed with error '%s'",
  96                     file, mode, major, minor, strerror(errno));
  97                 goto exit;
  98         }
  99
 100 perms:
 101         dbg("chmod(%s, %#o)", file, mode);
 102         if (chmod(file, mode) != 0) {
 103                 dbg("chmod(%s, %#o) failed with error '%s'", file, mode, strerror(errno));
 104                 goto exit;
 105         }
 106
 107         if (uid != 0 || gid != 0) {
 108                 dbg("chown(%s, %u, %u)", file, uid, gid);
 109                 if (chown(file, uid, gid) != 0) {
 110                         dbg("chown(%s, %u, %u) failed with error '%s'",
 111                             file, uid, gid, strerror(errno));
 112                         goto exit;
 113                 }
 114         }
 115
 116 exit:
 117         return retval;
 118 }
 119
 120 static int create_node(struct udevice *udev)
 121 {
 122         char filename[NAME_SIZE];
 123         char partitionname[NAME_SIZE];
 124         uid_t uid = 0;
 125         gid_t gid = 0;
 126         int i;
 127         int tail;
 128         char *pos;
 129         int len;
 130
 131         snprintf(filename, NAME_SIZE, "%s/%s", udev_root, udev->name);
 132         filename[NAME_SIZE-1] = '\0';
 133
 134         switch (udev->type) {
 135         case 'b':
 136                 udev->mode |= S_IFBLK;
 137                 break;
 138         case 'c':
 139         case 'u':
 140                 udev->mode |= S_IFCHR;
 141                 break;
 142         case 'p':
 143                 udev->mode |= S_IFIFO;
 144                 break;
 145         default:
 146                 dbg("unknown node type %c\n", udev->type);
 147                 return -EINVAL;
 148         }
 149
 150         /* create parent directories if needed */
 151         if (strrchr(udev->name, '/'))
 152                 create_path(filename);
 153
 154         if (udev->owner[0] != '\0') {
 155                 char *endptr;
 156                 unsigned long id = strtoul(udev->owner, &endptr, 10);
 157                 if (endptr[0] == '\0')
 158                         uid = (uid_t) id;
 159                 else {
 160                         struct passwd *pw;
 161
 162                         pw = getpwnam(udev->owner);
 163                         if (pw == NULL)
 164                                 dbg("specified user unknown '%s'", udev->owner);
 165                         else
 166                                 uid = pw->pw_uid;
 167                 }
 168         }
 169
 170         if (udev->group[0] != '\0') {
 171                 char *endptr;
 172                 unsigned long id = strtoul(udev->group, &endptr, 10);
 173                 if (endptr[0] == '\0')
 174                         gid = (gid_t) id;
 175                 else {
 176                         struct group *gr = getgrnam(udev->group);
 177                         if (gr == NULL)
 178                                 dbg("specified group unknown '%s'", udev->group);
 179                         else
 180                                 gid = gr->gr_gid;
 181                 }
 182         }
 183
 184         if (!udev->test_run) {
 185                 info("creating device node '%s'", filename);
 186                 if (udev_make_node(udev, filename, udev->major, udev->minor, udev->mode, uid, gid) != 0)
 187                         goto error;
 188         } else {
 189                 info("creating device node '%s', major = '%d', minor = '%d', "
 190                      "mode = '%#o', uid = '%d', gid = '%d'", filename,
 191                      udev->major, udev->minor, udev->mode, uid, gid);
 192         }
 193
 194         /* create all_partitions if requested */
 195         if (udev->partitions > 0) {
 196                 info("creating device partition nodes '%s[1-%i]'", filename, udev->partitions);
 197                 if (!udev->test_run) {
 198                         for (i = 1; i <= udev->partitions; i++) {
 199                                 strfieldcpy(partitionname, filename);
 200                                 strintcat(partitionname, i);
 201                                 udev_make_node(udev, partitionname, udev->major, udev->minor + i, udev->mode, uid, gid);
 202                         }
 203                 }
 204         }
 205
 206         /* create symlink(s) if requested */
 207         foreach_strpart(udev->symlink, " ", pos, len) {
 208                 char linkname[NAME_SIZE];
 209                 char linktarget[NAME_SIZE];
 210
 211                 strfieldcpymax(linkname, pos, len+1);
 212                 snprintf(filename, NAME_SIZE, "%s/%s", udev_root, linkname);
 213                 filename[NAME_SIZE-1] = '\0';
 214
 215                 dbg("symlink '%s' to node '%s' requested", filename, udev->name);
 216                 if (!udev->test_run)
 217                         if (strrchr(linkname, '/'))
 218                                 create_path(filename);
 219
 220                 /* optimize relative link */
 221                 linktarget[0] = '\0';
 222                 i = 0;
 223                 tail = 0;
 224                 while ((udev->name[i] == linkname[i]) && udev->name[i]) {
 225                         if (udev->name[i] == '/')
 226                                 tail = i+1;
 227                         i++;
 228                 }
 229                 while (linkname[i] != '\0') {
 230                         if (linkname[i] == '/')
 231                                 strfieldcat(linktarget, "../");
 232                         i++;
 233                 }
 234
 235                 strfieldcat(linktarget, &udev->name[tail]);
 236
 237                 dbg("symlink(%s, %s)", linktarget, filename);
 238                 if (!udev->test_run) {
 239                         selinux_setfscreatecon(filename, udev->kernel_name, S_IFLNK);
 240                         unlink(filename);
 241                         if (symlink(linktarget, filename) != 0)
 242                                 dbg("symlink(%s, %s) failed with error '%s'",
 243                                     linktarget, filename, strerror(errno));
 244                 }
 245         }
 246
 247         return 0;
 248 error:
 249         return -1;
 250 }
 251
 252 static int rename_net_if(struct udevice *udev)
 253 {
 254         int sk;
 255         struct ifreq ifr;
 256         int retval;
 257
 258         dbg("changing net interface name from '%s' to '%s'", udev->kernel_name, udev->name);
 259         if (udev->test_run)
 260                 return 0;
 261
 262         sk = socket(PF_INET, SOCK_DGRAM, 0);
 263         if (sk < 0) {
 264                 dbg("error opening socket");
 265                 return -1;
 266         }
 267
 268         memset(&ifr, 0x00, sizeof(struct ifreq));
 269         strfieldcpy(ifr.ifr_name, udev->kernel_name);
 270         strfieldcpy(ifr.ifr_newname, udev->name);
 271
 272         retval = ioctl(sk, SIOCSIFNAME, &ifr);
 273         if (retval != 0)
 274                 dbg("error changing net interface name");
 275         close(sk);
 276
 277         return retval;
 278 }
 279
 280 int udev_add_device(struct udevice *udev, struct sysfs_class_device *class_dev)
 281 {
 282         char *pos;
 283         int retval = 0;
 284
 285         if (udev->type == 'b' || udev->type == 'c') {
 286                 retval = get_major_minor(class_dev, udev);
 287                 if (retval != 0) {
 288                         dbg("no dev-file found, do nothing");
 289                         return 0;
 290                 }
 291         }
 292
 293         if (namedev_name_device(udev, class_dev) != 0)
 294                 return 0;
 295
 296         dbg("adding name='%s'", udev->name);
 297
 298         selinux_init();
 299
 300         if (udev->type == 'b' || udev->type == 'c') {
 301                 retval = create_node(udev);
 302                 if (retval != 0)
 303                         goto exit;
 304
 305                 if (udev_db_add_device(udev) != 0)
 306                         dbg("udev_db_add_dev failed, but we create the node anyway, "
 307                             "remove might not work for custom names");
 308
 309                 /* use full path to the environment */
 310                 snprintf(udev->devname, NAME_SIZE, "%s/%s", udev_root, udev->name);
 311                 udev->devname[NAME_SIZE-1] = '\0';
 312
 313         } else if (udev->type == 'n') {
 314                 /* look if we want to change the name of the netif */
 315                 if (strcmp(udev->name, udev->kernel_name) != 0) {
 316                         retval = rename_net_if(udev);
 317                         if (retval != 0)
 318                                 goto exit;
 319
 320                         /* we've changed the name, now fake the devpath, cause the
 321                          * original kernel name sleeps with the fishes and we don't
 322                          * get an event from the kernel with the new name
 323                          */
 324                         pos = strrchr(udev->devpath, '/');
 325                         if (pos != NULL) {
 326                                 pos[1] = '\0';
 327                                 strfieldcat(udev->devpath, udev->name);
 328                                 setenv("DEVPATH", udev->devpath, 1);
 329                                 setenv("INTERFACE", udev->name, 1);
 330                         }
 331
 332                         /* use netif name for the environment */
 333                         strfieldcpy(udev->devname, udev->name);
 334                 }
 335         }
 336
 337 exit:
 338         selinux_restore();
 339
 340         return retval;
 341 }