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_lib.h"
  42 #include "udev_version.h"
  43 #include "logging.h"
  44 #include "namedev.h"
  45 #include "udevdb.h"
  46
  47 #include "selinux.h"
  48
  49 /*
  50  * the major/minor of a device is stored in a file called "dev"
  51  * The number is stored in decimal values in the format: M:m
  52  */
  53 static int get_major_minor(struct sysfs_class_device *class_dev, struct udevice *udev)
  54 {
  55         struct sysfs_attribute *attr = NULL;
  56
  57         attr = sysfs_get_classdev_attr(class_dev, "dev");
  58         if (attr == NULL)
  59                 goto error;
  60         dbg("dev='%s'", attr->value);
  61
  62         if (sscanf(attr->value, "%u:%u", &udev->major, &udev->minor) != 2)
  63                 goto error;
  64         dbg("found major=%d, minor=%d", udev->major, udev->minor);
  65
  66         return 0;
  67 error:
  68         return -1;
  69 }
  70
  71 static int create_path(char *file)
  72 {
  73         char p[NAME_SIZE];
  74         char *pos;
  75         int retval;
  76         struct stat stats;
  77
  78         strfieldcpy(p, file);
  79         pos = strchr(p+1, '/');
  80         while (1) {
  81                 pos = strchr(pos+1, '/');
  82                 if (pos == NULL)
  83                         break;
  84                 *pos = 0x00;
  85                 if (stat(p, &stats)) {
  86                         selinux_setfscreatecon(p, S_IFDIR);
  87                         retval = mkdir(p, 0755);
  88                         if (retval != 0) {
  89                                 dbg("mkdir(%s) failed with error '%s'",
  90                                     p, strerror(errno));
  91                                 return retval;
  92                         }
  93                         dbg("created '%s'", p);
  94                 } else {
  95                         selinux_setfilecon(p, S_IFDIR);
  96                 }
  97                 *pos = '/';
  98         }
  99         return 0;
 100 }
 101
 102 static int make_node(char *file, int major, int minor, unsigned int mode, uid_t uid, gid_t gid)
 103 {
 104         struct stat stats;
 105         int retval = 0;
 106
 107         if (stat(file, &stats) != 0)
 108                 goto create;
 109
 110         /* preserve node with already correct numbers, to not change the inode number */
 111         if (((stats.st_mode & S_IFMT) == S_IFBLK || (stats.st_mode & S_IFMT) == S_IFCHR) &&
 112             (stats.st_rdev == makedev(major, minor))) {
 113                 dbg("preserve file '%s', cause it has correct dev_t", file);
 114                 selinux_setfilecon(file,stats.st_mode);
 115                 goto perms;
 116         }
 117
 118         if (unlink(file) != 0)
 119                 dbg("unlink(%s) failed with error '%s'", file, strerror(errno));
 120         else
 121                 dbg("already present file '%s' unlinked", file);
 122
 123 create:
 124         selinux_setfscreatecon(file, mode);
 125         retval = mknod(file, mode, makedev(major, minor));
 126         if (retval != 0) {
 127                 dbg("mknod(%s, %#o, %u, %u) failed with error '%s'",
 128                     file, mode, major, minor, strerror(errno));
 129                 goto exit;
 130         }
 131
 132 perms:
 133         dbg("chmod(%s, %#o)", file, mode);
 134         if (chmod(file, mode) != 0) {
 135                 dbg("chmod(%s, %#o) failed with error '%s'", file, mode, strerror(errno));
 136                 goto exit;
 137         }
 138
 139         if (uid != 0 || gid != 0) {
 140                 dbg("chown(%s, %u, %u)", file, uid, gid);
 141                 if (chown(file, uid, gid) != 0) {
 142                         dbg("chown(%s, %u, %u) failed with error '%s'",
 143                             file, uid, gid, strerror(errno));
 144                         goto exit;
 145                 }
 146         }
 147
 148 exit:
 149         return retval;
 150 }
 151
 152 static int create_node(struct udevice *udev)
 153 {
 154         char filename[NAME_SIZE];
 155         char linkname[NAME_SIZE];
 156         char linktarget[NAME_SIZE];
 157         char partitionname[NAME_SIZE];
 158         uid_t uid = 0;
 159         gid_t gid = 0;
 160         int i;
 161         int tail;
 162         char *pos;
 163         int len;
 164
 165         strfieldcpy(filename, udev_root);
 166         strfieldcat(filename, udev->name);
 167
 168         switch (udev->type) {
 169         case 'b':
 170                 udev->mode |= S_IFBLK;
 171                 break;
 172         case 'c':
 173         case 'u':
 174                 udev->mode |= S_IFCHR;
 175                 break;
 176         case 'p':
 177                 udev->mode |= S_IFIFO;
 178                 break;
 179         default:
 180                 dbg("unknown node type %c\n", udev->type);
 181                 return -EINVAL;
 182         }
 183
 184         /* create parent directories if needed */
 185         if (strrchr(udev->name, '/'))
 186                 create_path(filename);
 187
 188         if (udev->owner[0] != '\0') {
 189                 char *endptr;
 190                 unsigned long id = strtoul(udev->owner, &endptr, 10);
 191                 if (endptr[0] == '\0')
 192                         uid = (uid_t) id;
 193                 else {
 194                         struct passwd *pw;
 195
 196                         pw = getpwnam(udev->owner);
 197                         if (pw == NULL)
 198                                 dbg("specified user unknown '%s'", udev->owner);
 199                         else
 200                                 uid = pw->pw_uid;
 201                 }
 202         }
 203
 204         if (udev->group[0] != '\0') {
 205                 char *endptr;
 206                 unsigned long id = strtoul(udev->group, &endptr, 10);
 207                 if (endptr[0] == '\0')
 208                         gid = (gid_t) id;
 209                 else {
 210                         struct group *gr = getgrnam(udev->group);
 211                         if (gr == NULL)
 212                                 dbg("specified group unknown '%s'", udev->group);
 213                         else
 214                                 gid = gr->gr_gid;
 215                 }
 216         }
 217
 218         if (!udev->test_run) {
 219                 info("creating device node '%s'", filename);
 220                 if (make_node(filename, udev->major, udev->minor, udev->mode, uid, gid) != 0)
 221                         goto error;
 222         } else {
 223                 info("creating device node '%s', major = '%d', minor = '%d', "
 224                      "mode = '%#o', uid = '%d', gid = '%d'", filename,
 225                      udev->major, udev->minor, (mode_t)udev->mode, uid, gid);
 226         }
 227
 228         /* create all_partitions if requested */
 229         if (udev->partitions > 0) {
 230                 info("creating device partition nodes '%s[1-%i]'", filename, udev->partitions);
 231                 if (!udev->test_run) {
 232                         for (i = 1; i <= udev->partitions; i++) {
 233                                 strfieldcpy(partitionname, filename);
 234                                 strintcat(partitionname, i);
 235                                 make_node(partitionname, udev->major, udev->minor + i, udev->mode, uid, gid);
 236                         }
 237                 }
 238         }
 239
 240         /* create symlink(s) if requested */
 241         foreach_strpart(udev->symlink, " ", pos, len) {
 242                 strfieldcpymax(linkname, pos, len+1);
 243                 strfieldcpy(filename, udev_root);
 244                 strfieldcat(filename, linkname);
 245                 dbg("symlink '%s' to node '%s' requested", filename, udev->name);
 246                 if (!udev->test_run)
 247                         if (strrchr(linkname, '/'))
 248                                 create_path(filename);
 249
 250                 /* optimize relative link */
 251                 linktarget[0] = '\0';
 252                 i = 0;
 253                 tail = 0;
 254                 while ((udev->name[i] == linkname[i]) && udev->name[i]) {
 255                         if (udev->name[i] == '/')
 256                                 tail = i+1;
 257                         i++;
 258                 }
 259                 while (linkname[i] != '\0') {
 260                         if (linkname[i] == '/')
 261                                 strfieldcat(linktarget, "../");
 262                         i++;
 263                 }
 264
 265                 strfieldcat(linktarget, &udev->name[tail]);
 266
 267                 dbg("symlink(%s, %s)", linktarget, filename);
 268                 if (!udev->test_run) {
 269                         selinux_setfscreatecon(filename, S_IFLNK);
 270                         unlink(filename);
 271                         if (symlink(linktarget, filename) != 0)
 272                                 dbg("symlink(%s, %s) failed with error '%s'",
 273                                     linktarget, filename, strerror(errno));
 274                 }
 275         }
 276
 277         return 0;
 278 error:
 279         return -1;
 280 }
 281
 282 static int rename_net_if(struct udevice *udev)
 283 {
 284         int sk;
 285         struct ifreq ifr;
 286         int retval;
 287
 288         dbg("changing net interface name from '%s' to '%s'", udev->kernel_name, udev->name);
 289         if (udev->test_run)
 290                 return 0;
 291
 292         sk = socket(PF_INET, SOCK_DGRAM, 0);
 293         if (sk < 0) {
 294                 dbg("error opening socket");
 295                 return -1;
 296         }
 297
 298         memset(&ifr, 0x00, sizeof(struct ifreq));
 299         strfieldcpy(ifr.ifr_name, udev->kernel_name);
 300         strfieldcpy(ifr.ifr_newname, udev->name);
 301
 302         retval = ioctl(sk, SIOCSIFNAME, &ifr);
 303         if (retval != 0)
 304                 dbg("error changing net interface name");
 305         close(sk);
 306
 307         return retval;
 308 }
 309
 310 int udev_add_device(struct udevice *udev, struct sysfs_class_device *class_dev)
 311 {
 312         char *pos;
 313         int retval = 0;
 314
 315         if (udev->type == 'b' || udev->type == 'c') {
 316                 retval = get_major_minor(class_dev, udev);
 317                 if (retval != 0) {
 318                         dbg("no dev-file found, do nothing");
 319                         return 0;
 320                 }
 321         }
 322
 323         if (namedev_name_device(udev, class_dev) != 0)
 324                 goto exit;
 325
 326         dbg("adding name='%s'", udev->name);
 327
 328         selinux_init();
 329
 330         if (udev->type == 'b' || udev->type == 'c') {
 331                 retval = create_node(udev);
 332                 if (retval != 0)
 333                         goto exit;
 334
 335                 if (udevdb_add_dev(udev) != 0)
 336                         dbg("udevdb_add_dev failed, but we create the node anyway, "
 337                             "remove might not work for custom names");
 338
 339                 /* use full path to the environment */
 340                 snprintf(udev->devname, NAME_SIZE-1, "%s%s", udev_root, udev->name);
 341
 342         } else if (udev->type == 'n') {
 343                 /* look if we want to change the name of the netif */
 344                 if (strcmp(udev->name, udev->kernel_name) != 0) {
 345                         retval = rename_net_if(udev);
 346                         if (retval != 0)
 347                                 goto exit;
 348
 349                         /* we've changed the name, now fake the devpath,
 350                          * cause original kernel name sleeps with the fishes
 351                          * and we don't get any event from the kernel now
 352                          */
 353                         pos = strrchr(udev->devpath, '/');
 354                         if (pos != NULL) {
 355                                 pos[1] = '\0';
 356                                 strfieldcat(udev->devpath, udev->name);
 357                                 setenv("DEVPATH", udev->devpath, 1);
 358                         }
 359
 360                         /* use netif name for the environment */
 361                         strfieldcpy(udev->devname, udev->name);
 362                 }
 363         }
 364
 365 exit:
 366         selinux_restore();
 367
 368         return retval;
 369 }