udev/udev_device_event.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 <string.h>
  28 #include <sys/ioctl.h>
  29 #include <sys/socket.h>
  30 #include <net/if.h>
  31 #include <linux/sockios.h>
  32
  33 #include "udev.h"
  34 #include "udev_rules.h"
  35
  36
  37 static void kernel_log(struct ifreq ifr)
  38 {
  39         int klog;
  40         FILE *f;
  41
  42         klog = open("/dev/kmsg", O_WRONLY);
  43         if (klog < 0)
  44                 return;
  45
  46         f = fdopen(klog, "w");
  47         if (f == NULL) {
  48                 close(klog);
  49                 return;
  50         }
  51
  52         fprintf(f, "<6>udev: renamed network interface %s to %s\n",
  53                 ifr.ifr_name, ifr.ifr_newname);
  54         fclose(f);
  55 }
  56
  57 static int rename_netif(struct udevice *udev)
  58 {
  59         int sk;
  60         struct ifreq ifr;
  61         int retval;
  62
  63         info("changing net interface name from '%s' to '%s'\n", udev->dev->kernel, udev->name);
  64         if (udev->test_run)
  65                 return 0;
  66
  67         sk = socket(PF_INET, SOCK_DGRAM, 0);
  68         if (sk < 0) {
  69                 err("error opening socket: %s\n", strerror(errno));
  70                 return -1;
  71         }
  72
  73         memset(&ifr, 0x00, sizeof(struct ifreq));
  74         strlcpy(ifr.ifr_name, udev->dev->kernel, IFNAMSIZ);
  75         strlcpy(ifr.ifr_newname, udev->name, IFNAMSIZ);
  76         retval = ioctl(sk, SIOCSIFNAME, &ifr);
  77         if (retval == 0)
  78                 kernel_log(ifr);
  79         else {
  80                 int loop;
  81
  82                 /* see if the destination interface name already exists */
  83                 if (errno != EEXIST) {
  84                         err("error changing netif name %s to %s: %s\n", ifr.ifr_name, ifr.ifr_newname, strerror(errno));
  85                         goto exit;
  86                 }
  87
  88                 /* free our own name, another process may wait for us */
  89                 strlcpy(ifr.ifr_newname, udev->dev->kernel, IFNAMSIZ);
  90                 strlcat(ifr.ifr_newname, "_rename", IFNAMSIZ);
  91                 retval = ioctl(sk, SIOCSIFNAME, &ifr);
  92                 if (retval != 0) {
  93                         err("error changing netif name %s to %s: %s\n", ifr.ifr_name, ifr.ifr_newname, strerror(errno));
  94                         goto exit;
  95                 }
  96
  97                 /* wait 30 seconds for our target to become available */
  98                 strlcpy(ifr.ifr_name, ifr.ifr_newname, IFNAMSIZ);
  99                 strlcpy(ifr.ifr_newname, udev->name, IFNAMSIZ);
 100                 loop = 30 * 20;
 101                 while (loop--) {
 102                         retval = ioctl(sk, SIOCSIFNAME, &ifr);
 103                         if (retval == 0) {
 104                                 kernel_log(ifr);
 105                                 break;
 106                         }
 107
 108                         if (errno != EEXIST) {
 109                                 err("error changing net interface name %s to %s: %s\n",
 110                                     ifr.ifr_name, ifr.ifr_newname, strerror(errno));
 111                                 break;
 112                         }
 113                         dbg("wait for netif '%s' to become free, loop=%i\n", udev->name, (30 * 20) - loop);
 114                         usleep(1000 * 1000 / 20);
 115                 }
 116         }
 117
 118 exit:
 119         close(sk);
 120         return retval;
 121 }
 122
 123 int udev_device_event(struct udev_rules *rules, struct udevice *udev)
 124 {
 125         int retval = 0;
 126
 127         if (udev->devpath_old != NULL)
 128                 if (udev_db_rename(udev->devpath_old, udev->dev->devpath) == 0)
 129                         info("moved database from '%s' to '%s'\n", udev->devpath_old, udev->dev->devpath);
 130
 131         /* add device node */
 132         if (major(udev->devt) != 0 &&
 133             (strcmp(udev->action, "add") == 0 || strcmp(udev->action, "change") == 0)) {
 134                 struct udevice *udev_old;
 135
 136                 dbg("device node add '%s'\n", udev->dev->devpath);
 137
 138                 udev_rules_get_name(rules, udev);
 139                 if (udev->ignore_device) {
 140                         info("device event will be ignored\n");
 141                         goto exit;
 142                 }
 143                 if (udev->name[0] == '\0') {
 144                         info("device node creation supressed\n");
 145                         goto exit;
 146                 }
 147
 148                 /* read current database entry; cleanup, if it is known device */
 149                 udev_old = udev_device_init(NULL);
 150                 if (udev_old != NULL) {
 151                         udev_old->test_run = udev->test_run;
 152                         if (udev_db_get_device(udev_old, udev->dev->devpath) == 0) {
 153                                 info("device '%s' already in database, cleanup\n", udev->dev->devpath);
 154                                 udev_db_delete_device(udev_old);
 155                         } else {
 156                                 udev_device_cleanup(udev_old);
 157                                 udev_old = NULL;
 158                         }
 159                 }
 160
 161                 /* create node */
 162                 retval = udev_node_add(udev);
 163                 if (retval != 0)
 164                         goto exit;
 165
 166                 /* store in database */
 167                 udev_db_add_device(udev);
 168
 169                 /* create, replace, delete symlinks according to priority */
 170                 udev_node_update_symlinks(udev, udev_old);
 171
 172                 if (udev_old != NULL)
 173                         udev_device_cleanup(udev_old);
 174                 goto exit;
 175         }
 176
 177         /* add netif */
 178         if (strcmp(udev->dev->subsystem, "net") == 0 && strcmp(udev->action, "add") == 0) {
 179                 dbg("netif add '%s'\n", udev->dev->devpath);
 180                 udev_rules_get_name(rules, udev);
 181                 if (udev->ignore_device) {
 182                         info("device event will be ignored\n");
 183                         goto exit;
 184                 }
 185                 if (udev->name[0] == '\0') {
 186                         info("device renaming supressed\n");
 187                         goto exit;
 188                 }
 189
 190                 /* look if we want to change the name of the netif */
 191                 if (strcmp(udev->name, udev->dev->kernel) != 0) {
 192                         char devpath[PATH_MAX];
 193                         char *pos;
 194
 195                         retval = rename_netif(udev);
 196                         if (retval != 0)
 197                                 goto exit;
 198                         info("renamed netif to '%s'\n", udev->name);
 199
 200                         /* export old name */
 201                         setenv("INTERFACE_OLD", udev->dev->kernel, 1);
 202
 203                         /* now change the devpath, because the kernel device name has changed */
 204                         strlcpy(devpath, udev->dev->devpath, sizeof(devpath));
 205                         pos = strrchr(devpath, '/');
 206                         if (pos != NULL) {
 207                                 pos[1] = '\0';
 208                                 strlcat(devpath, udev->name, sizeof(devpath));
 209                                 sysfs_device_set_values(udev->dev, devpath, NULL, NULL);
 210                                 setenv("DEVPATH", udev->dev->devpath, 1);
 211                                 setenv("INTERFACE", udev->name, 1);
 212                                 info("changed devpath to '%s'\n", udev->dev->devpath);
 213                         }
 214                 }
 215                 goto exit;
 216         }
 217
 218         /* remove device node */
 219         if (major(udev->devt) != 0 && strcmp(udev->action, "remove") == 0) {
 220                 struct name_entry *name_loop;
 221
 222                 /* import database entry, and delete it */
 223                 if (udev_db_get_device(udev, udev->dev->devpath) == 0) {
 224                         udev_db_delete_device(udev);
 225                         /* restore stored persistent data */
 226                         list_for_each_entry(name_loop, &udev->env_list, node)
 227                                 putenv(name_loop->name);
 228                 } else {
 229                         dbg("'%s' not found in database, using kernel name '%s'\n",
 230                             udev->dev->devpath, udev->dev->kernel);
 231                         strlcpy(udev->name, udev->dev->kernel, sizeof(udev->name));
 232                 }
 233
 234                 udev_rules_get_run(rules, udev);
 235                 if (udev->ignore_device) {
 236                         info("device event will be ignored\n");
 237                         goto exit;
 238                 }
 239
 240                 if (udev->ignore_remove) {
 241                         info("ignore_remove for '%s'\n", udev->name);
 242                         goto exit;
 243                 }
 244                 /* remove the node */
 245                 retval = udev_node_remove(udev);
 246
 247                 /* delete or restore symlinks according to priority */
 248                 udev_node_update_symlinks(udev, NULL);
 249                 goto exit;
 250         }
 251
 252         /* default devices */
 253         udev_rules_get_run(rules, udev);
 254         if (udev->ignore_device)
 255                 info("device event will be ignored\n");
 256
 257 exit:
 258         return retval;
 259 }