udev_device.c

   1 /*
   2  * Copyright (C) 2004-2006 Kay Sievers <kay.sievers@vrfy.org>
   3  *
   4  *      This program is free software; you can redistribute it and/or modify it
   5  *      under the terms of the GNU General Public License as published by the
   6  *      Free Software Foundation version 2 of the License.
   7  *
   8  *      This program is distributed in the hope that it will be useful, but
   9  *      WITHOUT ANY WARRANTY; without even the implied warranty of
  10  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  *      General Public License for more details.
  12  *
  13  *      You should have received a copy of the GNU General Public License along
  14  *      with this program; if not, write to the Free Software Foundation, Inc.,
  15  *      51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  16  *
  17  */
  18
  19
  20 #include <stdlib.h>
  21 #include <stdio.h>
  22 #include <stddef.h>
  23 #include <unistd.h>
  24 #include <fcntl.h>
  25 #include <errno.h>
  26 #include <ctype.h>
  27 #include <sys/ioctl.h>
  28 #include <sys/socket.h>
  29 #include <net/if.h>
  30 #include <linux/sockios.h>
  31
  32 #include "udev.h"
  33 #include "udev_rules.h"
  34
  35
  36 struct udevice *udev_device_init(void)
  37 {
  38         struct udevice *udev;
  39
  40         udev = malloc(sizeof(struct udevice));
  41         if (udev == NULL)
  42                 return NULL;
  43         memset(udev, 0x00, sizeof(struct udevice));
  44
  45         INIT_LIST_HEAD(&udev->symlink_list);
  46         INIT_LIST_HEAD(&udev->run_list);
  47         INIT_LIST_HEAD(&udev->env_list);
  48
  49         /* set sysfs device to local storage, can be overridden if needed */
  50         udev->dev = &udev->dev_local;
  51
  52         /* default node permissions */
  53         udev->mode = 0660;
  54         strcpy(udev->owner, "root");
  55         strcpy(udev->group, "root");
  56
  57         return udev;
  58 }
  59
  60 void udev_device_cleanup(struct udevice *udev)
  61 {
  62         name_list_cleanup(&udev->symlink_list);
  63         name_list_cleanup(&udev->run_list);
  64         name_list_cleanup(&udev->env_list);
  65         free(udev);
  66 }
  67
  68 dev_t udev_device_get_devt(struct udevice *udev)
  69 {
  70         const char *attr;
  71         unsigned int maj, min;
  72
  73         /* read it from sysfs  */
  74         attr = sysfs_attr_get_value(udev->dev->devpath, "dev");
  75         if (attr != NULL) {
  76                 if (sscanf(attr, "%u:%u", &maj, &min) == 2)
  77                         return makedev(maj, min);
  78         }
  79         return makedev(0, 0);
  80 }
  81
  82 static int rename_netif(struct udevice *udev)
  83 {
  84         int sk;
  85         struct ifreq ifr;
  86         int retval;
  87
  88         info("changing net interface name from '%s' to '%s'", udev->dev->kernel, udev->name);
  89         if (udev->test_run)
  90                 return 0;
  91
  92         sk = socket(PF_INET, SOCK_DGRAM, 0);
  93         if (sk < 0) {
  94                 err("error opening socket: %s", strerror(errno));
  95                 return -1;
  96         }
  97
  98         memset(&ifr, 0x00, sizeof(struct ifreq));
  99         strlcpy(ifr.ifr_name, udev->dev->kernel, IFNAMSIZ);
 100         strlcpy(ifr.ifr_newname, udev->name, IFNAMSIZ);
 101         retval = ioctl(sk, SIOCSIFNAME, &ifr);
 102         if (retval != 0) {
 103                 int loop;
 104
 105                 /* see if the destination interface name already exists */
 106                 if (errno != EEXIST) {
 107                         err("error changing netif name %s to %s: %s", ifr.ifr_name, ifr.ifr_newname, strerror(errno));
 108                         goto exit;
 109                 }
 110
 111                 /* free our own name, another process may wait for us */
 112                 strlcpy(ifr.ifr_newname, udev->dev->kernel, IFNAMSIZ);
 113                 strlcat(ifr.ifr_newname, "_rename", IFNAMSIZ);
 114                 retval = ioctl(sk, SIOCSIFNAME, &ifr);
 115                 if (retval != 0) {
 116                         err("error changing netif name %s to %s: %s", ifr.ifr_name, ifr.ifr_newname, strerror(errno));
 117                         goto exit;
 118                 }
 119
 120                 /* wait 30 seconds for our target to become available */
 121                 strlcpy(ifr.ifr_name, ifr.ifr_newname, IFNAMSIZ);
 122                 strlcpy(ifr.ifr_newname, udev->name, IFNAMSIZ);
 123                 loop = 30 * 20;
 124                 while (loop--) {
 125                         retval = ioctl(sk, SIOCSIFNAME, &ifr);
 126                         if (retval == 0)
 127                                 break;
 128
 129                         if (errno != EEXIST) {
 130                                 err("error changing net interface name %s to %s: %s",
 131                                     ifr.ifr_name, ifr.ifr_newname, strerror(errno));
 132                                 break;
 133                         }
 134                         dbg("wait for netif '%s' to become free, loop=%i", udev->name, (30 * 20) - loop);
 135                         usleep(1000 * 1000 / 20);
 136                 }
 137         }
 138
 139 exit:
 140         close(sk);
 141         return retval;
 142 }
 143
 144 int udev_device_event(struct udev_rules *rules, struct udevice *udev)
 145 {
 146         int retval = 0;
 147
 148         /* add device node */
 149         if (major(udev->devt) != 0 &&
 150             (strcmp(udev->action, "add") == 0 || strcmp(udev->action, "change") == 0)) {
 151                 struct udevice *udev_old;
 152
 153                 dbg("device node add '%s'", udev->dev->devpath);
 154
 155                 udev_rules_get_name(rules, udev);
 156                 if (udev->ignore_device) {
 157                         info("device event will be ignored");
 158                         goto exit;
 159                 }
 160                 if (udev->name[0] == '\0') {
 161                         info("device node creation supressed");
 162                         goto exit;
 163                 }
 164
 165                 /* read current database entry, we may want to cleanup symlinks */
 166                 udev_old = udev_device_init();
 167                 if (udev_old != NULL) {
 168                         if (udev_db_get_device(udev_old, udev->dev->devpath) != 0) {
 169                                 udev_device_cleanup(udev_old);
 170                                 udev_old = NULL;
 171                         } else
 172                                 info("device '%s' already in database, validate currently present symlinks",
 173                                      udev->dev->devpath);
 174                 }
 175
 176                 /* create node and symlinks */
 177                 retval = udev_node_add(udev, udev_old);
 178                 if (retval == 0) {
 179                         /* store record in database */
 180                         udev_db_add_device(udev);
 181
 182                         /* remove possibly left-over symlinks */
 183                         if (udev_old != NULL) {
 184                                 struct name_entry *link_loop;
 185                                 struct name_entry *link_old_loop;
 186                                 struct name_entry *link_old_tmp_loop;
 187
 188                                 /* remove still valid symlinks from old list */
 189                                 list_for_each_entry_safe(link_old_loop, link_old_tmp_loop, &udev_old->symlink_list, node)
 190                                         list_for_each_entry(link_loop, &udev->symlink_list, node)
 191                                                 if (strcmp(link_old_loop->name, link_loop->name) == 0) {
 192                                                         dbg("symlink '%s' still valid, keep it", link_old_loop->name);
 193                                                         list_del(&link_old_loop->node);
 194                                                         free(link_old_loop);
 195                                                 }
 196                                 udev_node_remove_symlinks(udev_old);
 197                                 udev_device_cleanup(udev_old);
 198                         }
 199                 }
 200                 goto exit;
 201         }
 202
 203         /* add netif */
 204         if (strcmp(udev->dev->subsystem, "net") == 0 && strcmp(udev->action, "add") == 0) {
 205                 dbg("netif add '%s'", udev->dev->devpath);
 206                 udev_rules_get_name(rules, udev);
 207                 if (udev->ignore_device) {
 208                         info("device event will be ignored");
 209                         goto exit;
 210                 }
 211
 212                 /* look if we want to change the name of the netif */
 213                 if (strcmp(udev->name, udev->dev->kernel) != 0) {
 214                         char *pos;
 215
 216                         retval = rename_netif(udev);
 217                         if (retval != 0)
 218                                 goto exit;
 219                         info("renamed netif to '%s'", udev->name);
 220
 221                         /* export old name */
 222                         setenv("INTERFACE_OLD", udev->dev->kernel, 1);
 223
 224                         /* now fake the devpath, because the kernel name changed silently */
 225                         pos = strrchr(udev->dev->devpath, '/');
 226                         if (pos != NULL) {
 227                                 pos[1] = '\0';
 228                                 strlcat(udev->dev->devpath, udev->name, sizeof(udev->dev->devpath));
 229                                 strlcpy(udev->dev->kernel, udev->name, sizeof(udev->dev->kernel));
 230                                 setenv("DEVPATH", udev->dev->devpath, 1);
 231                                 setenv("INTERFACE", udev->name, 1);
 232                         }
 233                 }
 234                 goto exit;
 235         }
 236
 237         /* remove device node */
 238         if (major(udev->devt) != 0 && strcmp(udev->action, "remove") == 0) {
 239                 struct name_entry *name_loop;
 240
 241                 /* import and delete database entry */
 242                 if (udev_db_get_device(udev, udev->dev->devpath) == 0) {
 243                         udev_db_delete_device(udev);
 244                         if (udev->ignore_remove) {
 245                                 dbg("remove event for '%s' requested to be ignored by rule", udev->name);
 246                                 return 0;
 247                         }
 248                         /* restore stored persistent data */
 249                         list_for_each_entry(name_loop, &udev->env_list, node)
 250                                 putenv(name_loop->name);
 251                 } else {
 252                         dbg("'%s' not found in database, using kernel name '%s'", udev->dev->devpath, udev->dev->kernel);
 253                         strlcpy(udev->name, udev->dev->kernel, sizeof(udev->name));
 254                 }
 255
 256                 udev_rules_get_run(rules, udev);
 257                 if (udev->ignore_device) {
 258                         info("device event will be ignored");
 259                         goto exit;
 260                 }
 261
 262                 retval = udev_node_remove(udev);
 263                 goto exit;
 264         }
 265
 266         /* default devices */
 267         udev_rules_get_run(rules, udev);
 268         if (udev->ignore_device)
 269                 info("device event will be ignored");
 270
 271 exit:
 272         return retval;
 273 }