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 #ifndef __KLIBC__
  38 #include <pwd.h>
  39 #include <utmp.h>
  40 #endif
  41
  42 #include "libsysfs/sysfs/libsysfs.h"
  43 #include "udev.h"
  44 #include "udev_lib.h"
  45 #include "udev_version.h"
  46 #include "logging.h"
  47 #include "namedev.h"
  48 #include "udevdb.h"
  49 #include "klibc_fixups.h"
  50
  51 #include "selinux.h"
  52
  53 /*
  54  * the major/minor of a device is stored in a file called "dev"
  55  * The number is stored in decimal values in the format: M:m
  56  */
  57 static int get_major_minor(struct sysfs_class_device *class_dev, struct udevice *udev)
  58 {
  59         struct sysfs_attribute *attr = NULL;
  60
  61         attr = sysfs_get_classdev_attr(class_dev, "dev");
  62         if (attr == NULL)
  63                 goto error;
  64         dbg("dev='%s'", attr->value);
  65
  66         if (sscanf(attr->value, "%u:%u", &udev->major, &udev->minor) != 2)
  67                 goto error;
  68         dbg("found major=%d, minor=%d", udev->major, udev->minor);
  69
  70         return 0;
  71 error:
  72         return -1;
  73 }
  74
  75 static int create_path(char *file)
  76 {
  77         char p[NAME_SIZE];
  78         char *pos;
  79         int retval;
  80         struct stat stats;
  81
  82         strfieldcpy(p, file);
  83         pos = strchr(p+1, '/');
  84         while (1) {
  85                 pos = strchr(pos+1, '/');
  86                 if (pos == NULL)
  87                         break;
  88                 *pos = 0x00;
  89                 if (stat(p, &stats)) {
  90                         selinux_setfscreatecon(p, S_IFDIR);
  91                         retval = mkdir(p, 0755);
  92                         if (retval != 0) {
  93                                 dbg("mkdir(%s) failed with error '%s'",
  94                                     p, strerror(errno));
  95                                 return retval;
  96                         }
  97                         dbg("created '%s'", p);
  98                 } else {
  99                         selinux_setfilecon(p, S_IFDIR);
 100                 }
 101                 *pos = '/';
 102         }
 103         return 0;
 104 }
 105
 106 static int make_node(char *file, int major, int minor, unsigned int mode, uid_t uid, gid_t gid)
 107 {
 108         struct stat stats;
 109         int retval = 0;
 110
 111         if (stat(file, &stats) != 0)
 112                 goto create;
 113
 114         /* preserve node with already correct numbers, to not change the inode number */
 115         if (((stats.st_mode & S_IFMT) == S_IFBLK || (stats.st_mode & S_IFMT) == S_IFCHR) &&
 116             (stats.st_rdev == makedev(major, minor))) {
 117                 dbg("preserve file '%s', cause it has correct dev_t", file);
 118                 selinux_setfilecon(file,stats.st_mode);
 119                 goto perms;
 120         }
 121
 122         if (unlink(file) != 0)
 123                 dbg("unlink(%s) failed with error '%s'", file, strerror(errno));
 124         else
 125                 dbg("already present file '%s' unlinked", file);
 126
 127 create:
 128         selinux_setfscreatecon(file, mode);
 129         retval = mknod(file, mode, makedev(major, minor));
 130         if (retval != 0) {
 131                 dbg("mknod(%s, %#o, %u, %u) failed with error '%s'",
 132                     file, mode, major, minor, strerror(errno));
 133                 goto exit;
 134         }
 135
 136 perms:
 137         dbg("chmod(%s, %#o)", file, mode);
 138         if (chmod(file, mode) != 0) {
 139                 dbg("chmod(%s, %#o) failed with error '%s'", file, mode, strerror(errno));
 140                 goto exit;
 141         }
 142
 143         if (uid != 0 || gid != 0) {
 144                 dbg("chown(%s, %u, %u)", file, uid, gid);
 145                 if (chown(file, uid, gid) != 0) {
 146                         dbg("chown(%s, %u, %u) failed with error '%s'",
 147                             file, uid, gid, strerror(errno));
 148                         goto exit;
 149                 }
 150         }
 151
 152 exit:
 153         return retval;
 154 }
 155
 156 static int create_node(struct udevice *udev)
 157 {
 158         char filename[NAME_SIZE];
 159         char linkname[NAME_SIZE];
 160         char linktarget[NAME_SIZE];
 161         char partitionname[NAME_SIZE];
 162         uid_t uid = 0;
 163         gid_t gid = 0;
 164         int i;
 165         int tail;
 166         char *pos;
 167         int len;
 168
 169         strfieldcpy(filename, udev_root);
 170         strfieldcat(filename, udev->name);
 171
 172         switch (udev->type) {
 173         case 'b':
 174                 udev->mode |= S_IFBLK;
 175                 break;
 176         case 'c':
 177         case 'u':
 178                 udev->mode |= S_IFCHR;
 179                 break;
 180         case 'p':
 181                 udev->mode |= S_IFIFO;
 182                 break;
 183         default:
 184                 dbg("unknown node type %c\n", udev->type);
 185                 return -EINVAL;
 186         }
 187
 188         /* create parent directories if needed */
 189         if (strrchr(udev->name, '/'))
 190                 create_path(filename);
 191
 192         if (udev->owner[0] != '\0') {
 193                 char *endptr;
 194                 unsigned long id = strtoul(udev->owner, &endptr, 10);
 195                 if (endptr[0] == '\0')
 196                         uid = (uid_t) id;
 197                 else {
 198                         struct passwd *pw;
 199
 200                         pw = getpwnam(udev->owner);
 201                         if (pw == NULL)
 202                                 dbg("specified user unknown '%s'", udev->owner);
 203                         else
 204                                 uid = pw->pw_uid;
 205                 }
 206         }
 207
 208         if (udev->group[0] != '\0') {
 209                 char *endptr;
 210                 unsigned long id = strtoul(udev->group, &endptr, 10);
 211                 if (endptr[0] == '\0')
 212                         gid = (gid_t) id;
 213                 else {
 214                         struct group *gr = getgrnam(udev->group);
 215                         if (gr == NULL)
 216                                 dbg("specified group unknown '%s'", udev->group);
 217                         else
 218                                 gid = gr->gr_gid;
 219                 }
 220         }
 221
 222         if (!udev->test_run) {
 223                 info("creating device node '%s'", filename);
 224                 if (make_node(filename, udev->major, udev->minor, udev->mode, uid, gid) != 0)
 225                         goto error;
 226         } else {
 227                 info("creating device node '%s', major = '%d', minor = '%d', "
 228                      "mode = '%#o', uid = '%d', gid = '%d'", filename,
 229                      udev->major, udev->minor, (mode_t)udev->mode, uid, gid);
 230         }
 231
 232         /* create all_partitions if requested */
 233         if (udev->partitions > 0) {
 234                 info("creating device partition nodes '%s[1-%i]'", filename, udev->partitions);
 235                 if (!udev->test_run) {
 236                         for (i = 1; i <= udev->partitions; i++) {
 237                                 strfieldcpy(partitionname, filename);
 238                                 strintcat(partitionname, i);
 239                                 make_node(partitionname, udev->major, udev->minor + i, udev->mode, uid, gid);
 240                         }
 241                 }
 242         }
 243
 244         /* create symlink(s) if requested */
 245         foreach_strpart(udev->symlink, " ", pos, len) {
 246                 strfieldcpymax(linkname, pos, len+1);
 247                 strfieldcpy(filename, udev_root);
 248                 strfieldcat(filename, linkname);
 249                 dbg("symlink '%s' to node '%s' requested", filename, udev->name);
 250                 if (!udev->test_run)
 251                         if (strrchr(linkname, '/'))
 252                                 create_path(filename);
 253
 254                 /* optimize relative link */
 255                 linktarget[0] = '\0';
 256                 i = 0;
 257                 tail = 0;
 258                 while ((udev->name[i] == linkname[i]) && udev->name[i]) {
 259                         if (udev->name[i] == '/')
 260                                 tail = i+1;
 261                         i++;
 262                 }
 263                 while (linkname[i] != '\0') {
 264                         if (linkname[i] == '/')
 265                                 strfieldcat(linktarget, "../");
 266                         i++;
 267                 }
 268
 269                 strfieldcat(linktarget, &udev->name[tail]);
 270
 271                 dbg("symlink(%s, %s)", linktarget, filename);
 272                 if (!udev->test_run) {
 273                         selinux_setfscreatecon(filename, S_IFLNK);
 274                         unlink(filename);
 275                         if (symlink(linktarget, filename) != 0)
 276                                 dbg("symlink(%s, %s) failed with error '%s'",
 277                                     linktarget, filename, strerror(errno));
 278                 }
 279         }
 280
 281         return 0;
 282 error:
 283         return -1;
 284 }
 285
 286 static int rename_net_if(struct udevice *udev)
 287 {
 288         int sk;
 289         struct ifreq ifr;
 290         int retval;
 291
 292         dbg("changing net interface name from '%s' to '%s'", udev->kernel_name, udev->name);
 293         if (udev->test_run)
 294                 return 0;
 295
 296         sk = socket(PF_INET, SOCK_DGRAM, 0);
 297         if (sk < 0) {
 298                 dbg("error opening socket");
 299                 return -1;
 300         }
 301
 302         memset(&ifr, 0x00, sizeof(struct ifreq));
 303         strfieldcpy(ifr.ifr_name, udev->kernel_name);
 304         strfieldcpy(ifr.ifr_newname, udev->name);
 305
 306         retval = ioctl(sk, SIOCSIFNAME, &ifr);
 307         if (retval != 0)
 308                 dbg("error changing net interface name");
 309         close(sk);
 310
 311         return retval;
 312 }
 313
 314 int udev_add_device(struct udevice *udev, struct sysfs_class_device *class_dev)
 315 {
 316         char *pos;
 317         int retval = 0;
 318
 319         if (udev->type == 'b' || udev->type == 'c') {
 320                 retval = get_major_minor(class_dev, udev);
 321                 if (retval != 0) {
 322                         dbg("no dev-file found, do nothing");
 323                         return 0;
 324                 }
 325         }
 326
 327         if (namedev_name_device(udev, class_dev) != 0)
 328                 goto exit;
 329
 330         dbg("adding name='%s'", udev->name);
 331
 332         selinux_init();
 333
 334         if (udev->type == 'b' || udev->type == 'c') {
 335                 retval = create_node(udev);
 336                 if (retval != 0)
 337                         goto exit;
 338
 339                 if (udevdb_add_dev(udev) != 0)
 340                         dbg("udevdb_add_dev failed, but we create the node anyway, "
 341                             "remove might not work for custom names");
 342
 343                 /* use full path to the environment */
 344                 snprintf(udev->devname, NAME_SIZE-1, "%s%s", udev_root, udev->name);
 345
 346         } else if (udev->type == 'n') {
 347                 /* look if we want to change the name of the netif */
 348                 if (strcmp(udev->name, udev->kernel_name) != 0) {
 349                         retval = rename_net_if(udev);
 350                         if (retval != 0)
 351                                 goto exit;
 352
 353                         /* we've changed the name, now fake the devpath,
 354                          * cause original kernel name sleeps with the fishes
 355                          * and we don't get any event from the kernel now
 356                          */
 357                         pos = strrchr(udev->devpath, '/');
 358                         if (pos != NULL) {
 359                                 pos[1] = '\0';
 360                                 strfieldcat(udev->devpath, udev->name);
 361                                 setenv("DEVPATH", udev->devpath, 1);
 362                         }
 363
 364                         /* use netif name for the environment */
 365                         strfieldcpy(udev->devname, udev->name);
 366                 }
 367         }
 368
 369 exit:
 370         selinux_restore();
 371
 372         return retval;
 373 }