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 #define LOCAL_USER "$local"
  52
  53 #include "selinux.h"
  54
  55 /*
  56  * the major/minor of a device is stored in a file called "dev"
  57  * The number is stored in decimal values in the format: M:m
  58  */
  59 static int get_major_minor(struct sysfs_class_device *class_dev, struct udevice *udev)
  60 {
  61         struct sysfs_attribute *attr = NULL;
  62
  63         attr = sysfs_get_classdev_attr(class_dev, "dev");
  64         if (attr == NULL)
  65                 goto error;
  66         dbg("dev='%s'", attr->value);
  67
  68         if (sscanf(attr->value, "%u:%u", &udev->major, &udev->minor) != 2)
  69                 goto error;
  70         dbg("found major=%d, minor=%d", udev->major, udev->minor);
  71
  72         return 0;
  73 error:
  74         return -1;
  75 }
  76
  77 static int create_path(char *file)
  78 {
  79         char p[NAME_SIZE];
  80         char *pos;
  81         int retval;
  82         struct stat stats;
  83
  84         strfieldcpy(p, file);
  85         pos = strchr(p+1, '/');
  86         while (1) {
  87                 pos = strchr(pos+1, '/');
  88                 if (pos == NULL)
  89                         break;
  90                 *pos = 0x00;
  91                 if (stat(p, &stats)) {
  92                         selinux_setfscreatecon(p, S_IFDIR);
  93                         retval = mkdir(p, 0755);
  94                         if (retval != 0) {
  95                                 dbg("mkdir(%s) failed with error '%s'",
  96                                     p, strerror(errno));
  97                                 return retval;
  98                         }
  99                         dbg("created '%s'", p);
 100                 } else {
 101                         selinux_setfilecon(p, S_IFDIR);
 102                 }
 103                 *pos = '/';
 104         }
 105         return 0;
 106 }
 107
 108 static int make_node(char *file, int major, int minor, unsigned int mode, uid_t uid, gid_t gid)
 109 {
 110         struct stat stats;
 111         int retval = 0;
 112
 113         if (stat(file, &stats) != 0)
 114                 goto create;
 115
 116         /* preserve node with already correct numbers, to not change the inode number */
 117         if (((stats.st_mode & S_IFMT) == S_IFBLK || (stats.st_mode & S_IFMT) == S_IFCHR) &&
 118             (stats.st_rdev == makedev(major, minor))) {
 119                 dbg("preserve file '%s', cause it has correct dev_t", file);
 120                 selinux_setfilecon(file,stats.st_mode);
 121                 goto perms;
 122         }
 123
 124         if (unlink(file) != 0)
 125                 dbg("unlink(%s) failed with error '%s'", file, strerror(errno));
 126         else
 127                 dbg("already present file '%s' unlinked", file);
 128
 129 create:
 130         selinux_setfscreatecon(file, mode);
 131         retval = mknod(file, mode, makedev(major, minor));
 132         if (retval != 0) {
 133                 dbg("mknod(%s, %#o, %u, %u) failed with error '%s'",
 134                     file, mode, major, minor, strerror(errno));
 135                 goto exit;
 136         }
 137
 138 perms:
 139         dbg("chmod(%s, %#o)", file, mode);
 140         if (chmod(file, mode) != 0) {
 141                 dbg("chmod(%s, %#o) failed with error '%s'", file, mode, strerror(errno));
 142                 goto exit;
 143         }
 144
 145         if (uid != 0 || gid != 0) {
 146                 dbg("chown(%s, %u, %u)", file, uid, gid);
 147                 if (chown(file, uid, gid) != 0) {
 148                         dbg("chown(%s, %u, %u) failed with error '%s'",
 149                             file, uid, gid, strerror(errno));
 150                         goto exit;
 151                 }
 152         }
 153
 154 exit:
 155         return retval;
 156 }
 157
 158 /* get the local logged in user */
 159 static void set_to_local_user(char *user)
 160 {
 161         struct utmp *u;
 162         time_t recent = 0;
 163
 164         strfieldcpymax(user, default_owner_str, OWNER_SIZE);
 165         setutent();
 166         while (1) {
 167                 u = getutent();
 168                 if (u == NULL)
 169                         break;
 170
 171                 /* is this a user login ? */
 172                 if (u->ut_type != USER_PROCESS)
 173                         continue;
 174
 175                 /* is this a local login ? */
 176                 if (strcmp(u->ut_host, ""))
 177                         continue;
 178
 179                 if (u->ut_time > recent) {
 180                         recent = u->ut_time;
 181                         strfieldcpymax(user, u->ut_user, OWNER_SIZE);
 182                         dbg("local user is '%s'", user);
 183                         break;
 184                 }
 185         }
 186         endutent();
 187 }
 188
 189 static int create_node(struct udevice *udev)
 190 {
 191         char filename[NAME_SIZE];
 192         char linkname[NAME_SIZE];
 193         char linktarget[NAME_SIZE];
 194         char partitionname[NAME_SIZE];
 195         uid_t uid = 0;
 196         gid_t gid = 0;
 197         int i;
 198         int tail;
 199         char *pos;
 200         int len;
 201
 202         strfieldcpy(filename, udev_root);
 203         strfieldcat(filename, udev->name);
 204
 205         switch (udev->type) {
 206         case 'b':
 207                 udev->mode |= S_IFBLK;
 208                 break;
 209         case 'c':
 210         case 'u':
 211                 udev->mode |= S_IFCHR;
 212                 break;
 213         case 'p':
 214                 udev->mode |= S_IFIFO;
 215                 break;
 216         default:
 217                 dbg("unknown node type %c\n", udev->type);
 218                 return -EINVAL;
 219         }
 220
 221         /* create parent directories if needed */
 222         if (strrchr(udev->name, '/'))
 223                 create_path(filename);
 224
 225         if (udev->owner[0] != '\0') {
 226                 char *endptr;
 227                 unsigned long id = strtoul(udev->owner, &endptr, 10);
 228                 if (endptr[0] == '\0')
 229                         uid = (uid_t) id;
 230                 else {
 231                         struct passwd *pw;
 232                         if (strncmp(udev->owner, LOCAL_USER, sizeof(LOCAL_USER)) == 0)
 233                                 set_to_local_user(udev->owner);
 234
 235                         pw = getpwnam(udev->owner);
 236                         if (pw == NULL)
 237                                 dbg("specified user unknown '%s'", udev->owner);
 238                         else
 239                                 uid = pw->pw_uid;
 240                 }
 241         }
 242
 243         if (udev->group[0] != '\0') {
 244                 char *endptr;
 245                 unsigned long id = strtoul(udev->group, &endptr, 10);
 246                 if (endptr[0] == '\0')
 247                         gid = (gid_t) id;
 248                 else {
 249                         struct group *gr = getgrnam(udev->group);
 250                         if (gr == NULL)
 251                                 dbg("specified group unknown '%s'", udev->group);
 252                         else
 253                                 gid = gr->gr_gid;
 254                 }
 255         }
 256
 257         if (!udev->test_run) {
 258                 info("creating device node '%s'", filename);
 259                 if (make_node(filename, udev->major, udev->minor, udev->mode, uid, gid) != 0)
 260                         goto error;
 261         } else {
 262                 info("creating device node '%s', major = '%d', minor = '%d', "
 263                      "mode = '%#o', uid = '%d', gid = '%d'", filename,
 264                      udev->major, udev->minor, (mode_t)udev->mode, uid, gid);
 265         }
 266
 267         /* create all_partitions if requested */
 268         if (udev->partitions > 0) {
 269                 info("creating device partition nodes '%s[1-%i]'", filename, udev->partitions);
 270                 if (!udev->test_run) {
 271                         for (i = 1; i <= udev->partitions; i++) {
 272                                 strfieldcpy(partitionname, filename);
 273                                 strintcat(partitionname, i);
 274                                 make_node(partitionname, udev->major, udev->minor + i, udev->mode, uid, gid);
 275                         }
 276                 }
 277         }
 278
 279         /* create symlink(s) if requested */
 280         foreach_strpart(udev->symlink, " ", pos, len) {
 281                 strfieldcpymax(linkname, pos, len+1);
 282                 strfieldcpy(filename, udev_root);
 283                 strfieldcat(filename, linkname);
 284                 dbg("symlink '%s' to node '%s' requested", filename, udev->name);
 285                 if (!udev->test_run)
 286                         if (strrchr(linkname, '/'))
 287                                 create_path(filename);
 288
 289                 /* optimize relative link */
 290                 linktarget[0] = '\0';
 291                 i = 0;
 292                 tail = 0;
 293                 while ((udev->name[i] == linkname[i]) && udev->name[i]) {
 294                         if (udev->name[i] == '/')
 295                                 tail = i+1;
 296                         i++;
 297                 }
 298                 while (linkname[i] != '\0') {
 299                         if (linkname[i] == '/')
 300                                 strfieldcat(linktarget, "../");
 301                         i++;
 302                 }
 303
 304                 strfieldcat(linktarget, &udev->name[tail]);
 305
 306                 dbg("symlink(%s, %s)", linktarget, filename);
 307                 if (!udev->test_run) {
 308                         selinux_setfscreatecon(filename, S_IFLNK);
 309                         unlink(filename);
 310                         if (symlink(linktarget, filename) != 0)
 311                                 dbg("symlink(%s, %s) failed with error '%s'",
 312                                     linktarget, filename, strerror(errno));
 313                 }
 314         }
 315
 316         return 0;
 317 error:
 318         return -1;
 319 }
 320
 321 static int rename_net_if(struct udevice *udev)
 322 {
 323         int sk;
 324         struct ifreq ifr;
 325         int retval;
 326
 327         dbg("changing net interface name from '%s' to '%s'", udev->kernel_name, udev->name);
 328         if (udev->test_run)
 329                 return 0;
 330
 331         sk = socket(PF_INET, SOCK_DGRAM, 0);
 332         if (sk < 0) {
 333                 dbg("error opening socket");
 334                 return -1;
 335         }
 336
 337         memset(&ifr, 0x00, sizeof(struct ifreq));
 338         strfieldcpy(ifr.ifr_name, udev->kernel_name);
 339         strfieldcpy(ifr.ifr_newname, udev->name);
 340
 341         retval = ioctl(sk, SIOCSIFNAME, &ifr);
 342         if (retval != 0)
 343                 dbg("error changing net interface name");
 344         close(sk);
 345
 346         return retval;
 347 }
 348
 349 int udev_add_device(struct udevice *udev, struct sysfs_class_device *class_dev)
 350 {
 351         char *pos;
 352         int retval = 0;
 353
 354         if (udev->type == 'b' || udev->type == 'c') {
 355                 retval = get_major_minor(class_dev, udev);
 356                 if (retval != 0) {
 357                         dbg("no dev-file found, do nothing");
 358                         return 0;
 359                 }
 360         }
 361
 362         if (namedev_name_device(udev, class_dev) != 0)
 363                 goto exit;
 364
 365         dbg("adding name='%s'", udev->name);
 366
 367         selinux_init();
 368
 369         if (udev->type == 'b' || udev->type == 'c') {
 370                 retval = create_node(udev);
 371                 if (retval != 0)
 372                         goto exit;
 373
 374                 if (udevdb_add_dev(udev) != 0)
 375                         dbg("udevdb_add_dev failed, but we create the node anyway, "
 376                             "remove might not work for custom names");
 377
 378                 /* use full path to the environment */
 379                 snprintf(udev->devname, NAME_SIZE-1, "%s%s", udev_root, udev->name);
 380
 381         } else if (udev->type == 'n') {
 382                 /* look if we want to change the name of the netif */
 383                 if (strcmp(udev->name, udev->kernel_name) != 0) {
 384                         retval = rename_net_if(udev);
 385                         if (retval != 0)
 386                                 goto exit;
 387
 388                         /* we've changed the name, now fake the devpath,
 389                          * cause original kernel name sleeps with the fishes
 390                          * and we don't get any event from the kernel now
 391                          */
 392                         pos = strrchr(udev->devpath, '/');
 393                         if (pos != NULL) {
 394                                 pos[1] = '\0';
 395                                 strfieldcat(udev->devpath, udev->name);
 396                                 setenv("DEVPATH", udev->devpath, 1);
 397                         }
 398
 399                         /* use netif name for the environment */
 400                         strfieldcpy(udev->devname, udev->name);
 401                 }
 402         }
 403
 404 exit:
 405         selinux_restore();
 406
 407         return retval;
 408 }