udev.c

   1 /*
   2  * udev.c
   3  *
   4  * Userspace devfs
   5  *
   6  * Copyright (C) 2003,2004 Greg Kroah-Hartman <greg@kroah.com>
   7  * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
   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 <stdio.h>
  25 #include <stddef.h>
  26 #include <stdlib.h>
  27 #include <string.h>
  28 #include <fcntl.h>
  29 #include <ctype.h>
  30 #include <errno.h>
  31 #include <signal.h>
  32 #include <unistd.h>
  33
  34 #include "libsysfs/sysfs/libsysfs.h"
  35 #include "udev_libc_wrapper.h"
  36 #include "udev.h"
  37 #include "udev_utils.h"
  38 #include "udev_sysfs.h"
  39 #include "udev_version.h"
  40 #include "udev_rules.h"
  41 #include "logging.h"
  42
  43 #ifdef USE_LOG
  44 void log_message(int priority, const char *format, ...)
  45 {
  46         va_list args;
  47
  48         if (priority > udev_log_priority)
  49                 return;
  50
  51         va_start(args, format);
  52         vsyslog(priority, format, args);
  53         va_end(args);
  54 }
  55 #endif
  56
  57 static void asmlinkage sig_handler(int signum)
  58 {
  59         switch (signum) {
  60                 case SIGALRM:
  61                         exit(1);
  62                 case SIGINT:
  63                 case SIGTERM:
  64                         exit(20 + signum);
  65         }
  66 }
  67
  68 int main(int argc, char *argv[], char *envp[])
  69 {
  70         struct udevice udev;
  71         char path[PATH_SIZE];
  72         const char *error;
  73         const char *action;
  74         const char *devpath;
  75         const char *subsystem;
  76         struct sigaction act;
  77         int retval = -EINVAL;
  78
  79         if (argc == 2 && strcmp(argv[1], "-V") == 0) {
  80                 printf("%s\n", UDEV_VERSION);
  81                 exit(0);
  82         }
  83
  84         logging_init("udev");
  85         udev_init_config();
  86         dbg("version %s", UDEV_VERSION);
  87
  88         /* set signal handlers */
  89         memset(&act, 0x00, sizeof(act));
  90         act.sa_handler = (void (*)(int)) sig_handler;
  91         sigemptyset (&act.sa_mask);
  92         act.sa_flags = 0;
  93         sigaction(SIGALRM, &act, NULL);
  94         sigaction(SIGINT, &act, NULL);
  95         sigaction(SIGTERM, &act, NULL);
  96
  97         /* trigger timeout to prevent hanging processes */
  98         alarm(ALARM_TIMEOUT);
  99
 100         action = getenv("ACTION");
 101         devpath = getenv("DEVPATH");
 102         subsystem = getenv("SUBSYSTEM");
 103         /* older kernels passed the SUBSYSTEM only as argument */
 104         if (!subsystem && argc == 2)
 105                 subsystem = argv[1];
 106
 107         if (!action || !subsystem || !devpath) {
 108                 err("action, subsystem or devpath missing");
 109                 goto exit;
 110         }
 111
 112         /* export log_priority , as called programs may want to do the same as udev */
 113         if (udev_log_priority) {
 114                 char priority[32];
 115
 116                 sprintf(priority, "%i", udev_log_priority);
 117                 setenv("UDEV_LOG", priority, 1);
 118         }
 119
 120         udev_init_device(&udev, devpath, subsystem, action);
 121         udev_rules_init();
 122
 123         if (udev.type == DEV_BLOCK || udev.type == DEV_CLASS || udev.type == DEV_NET) {
 124                 /* handle device node */
 125                 if (strcmp(action, "add") == 0) {
 126                         struct sysfs_class_device *class_dev;
 127
 128                         /* wait for sysfs of /sys/class /sys/block */
 129                         dbg("node add");
 130                         snprintf(path, sizeof(path), "%s%s", sysfs_path, udev.devpath);
 131                         path[sizeof(path)-1] = '\0';
 132                         class_dev = wait_class_device_open(path);
 133                         if (class_dev == NULL) {
 134                                 dbg("open class device failed");
 135                                 goto run;
 136                         }
 137                         dbg("opened class_dev->name='%s'", class_dev->name);
 138                         wait_for_class_device(class_dev, &error);
 139
 140                         /* get major/minor */
 141                         if (udev.type == DEV_BLOCK || udev.type == DEV_CLASS)
 142                                 udev.devt = get_devt(class_dev);
 143
 144                         if (udev.type == DEV_NET || udev.devt) {
 145                                 /* name device */
 146                                 udev_rules_get_name(&udev, class_dev);
 147                                 if (udev.ignore_device) {
 148                                         info("device event will be ignored");
 149                                         goto cleanup;
 150                                 }
 151                                 if (udev.name[0] == '\0') {
 152                                         info("device node creation supressed");
 153                                         goto cleanup;
 154                                 }
 155
 156                                 /* create node, store in db */
 157                                 retval = udev_add_device(&udev, class_dev);
 158                         } else {
 159                                 dbg("no dev-file found");
 160                                 udev_rules_get_run(&udev, NULL);
 161                                 if (udev.ignore_device) {
 162                                         info("device event will be ignored");
 163                                         goto cleanup;
 164                                 }
 165                         }
 166                         sysfs_close_class_device(class_dev);
 167                 } else if (strcmp(action, "remove") == 0) {
 168                         dbg("node remove");
 169                         udev_rules_get_run(&udev, NULL);
 170                         if (udev.ignore_device) {
 171                                 dbg("device event will be ignored");
 172                                 goto cleanup;
 173                         }
 174
 175                         /* get name from db, remove db-entry, delete node */
 176                         retval = udev_remove_device(&udev);
 177                 }
 178
 179                 /* export name of device node or netif */
 180                 if (udev.devname[0] != '\0')
 181                         setenv("DEVNAME", udev.devname, 1);
 182         } else if (udev.type == DEV_DEVICE && strcmp(action, "add") == 0) {
 183                 struct sysfs_device *devices_dev;
 184
 185                 /* wait for sysfs of /sys/devices/ */
 186                 dbg("devices add");
 187                 snprintf(path, sizeof(path), "%s%s", sysfs_path, devpath);
 188                 path[sizeof(path)-1] = '\0';
 189                 devices_dev = wait_devices_device_open(path);
 190                 if (!devices_dev) {
 191                         dbg("devices device unavailable (probably remove has beaten us)");
 192                         goto run;
 193                 }
 194                 dbg("devices device opened '%s'", path);
 195                 wait_for_devices_device(devices_dev, &error);
 196                 udev_rules_get_run(&udev, devices_dev);
 197                 sysfs_close_device(devices_dev);
 198                 if (udev.ignore_device) {
 199                         info("device event will be ignored");
 200                         goto cleanup;
 201                 }
 202         } else {
 203                 dbg("default handling");
 204                 udev_rules_get_run(&udev, NULL);
 205                 if (udev.ignore_device) {
 206                         info("device event will be ignored");
 207                         goto cleanup;
 208                 }
 209         }
 210
 211 run:
 212         if (udev_run && !list_empty(&udev.run_list)) {
 213                 struct name_entry *name_loop;
 214
 215                 dbg("executing run list");
 216                 list_for_each_entry(name_loop, &udev.run_list, node)
 217                         execute_program(name_loop->name, udev.subsystem, NULL, 0, NULL);
 218         }
 219
 220 cleanup:
 221         udev_cleanup_device(&udev);
 222
 223 exit:
 224         logging_close();
 225         return retval;
 226 }