udev.c revision e5e322bc627a07d29a07e08f7c96bd644a3ae057
/*
* udev.c
*
* Userspace devfs
*
* Copyright (C) 2003,2004 Greg Kroah-Hartman <greg@kroah.com>
* Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation version 2 of the License.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 675 Mass Ave, Cambridge, MA 02139, USA.
*
*/
#include <stdio.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <ctype.h>
#include <errno.h>
#include <signal.h>
#include <unistd.h>
#include "libsysfs/sysfs/libsysfs.h"
#include "udev_libc_wrapper.h"
#include "udev.h"
#include "udev_utils.h"
#include "udev_sysfs.h"
#include "udev_version.h"
#include "udev_rules.h"
#include "logging.h"
#ifdef USE_LOG
void log_message(int level, const char *format, ...)
{
va_list args;
if (!udev_log)
return;
va_start(args, format);
vsyslog(level, format, args);
va_end(args);
}
#endif
/* decide if we should manage the whole hotplug event
* for now look if the kernel calls udevsend instead of /sbin/hotplug
*/
static int manage_hotplug_event(void) {
char helper[256];
int fd;
int len;
/* don't handle hotplug.d if we are called directly */
if (!getenv("UDEVD_EVENT"))
return 0;
fd = open("/proc/sys/kernel/hotplug", O_RDONLY);
if (fd < 0)
return 0;
len = read(fd, helper, 256);
close(fd);
if (len < 0)
return 0;
helper[len] = '\0';
if (strstr(helper, "udevsend"))
return 1;
return 0;
}
static void asmlinkage sig_handler(int signum)
{
switch (signum) {
case SIGALRM:
exit(1);
case SIGINT:
case SIGTERM:
exit(20 + signum);
}
}
int main(int argc, char *argv[], char *envp[])
{
struct sysfs_class_device *class_dev;
struct sysfs_device *devices_dev;
struct udevice udev;
char path[PATH_SIZE];
const char *error;
const char *action;
const char *devpath;
const char *subsystem;
int managed_event;
struct sigaction act;
int retval = -EINVAL;
if (argc == 2 && strcmp(argv[1], "-V") == 0) {
printf("%s\n", UDEV_VERSION);
exit(0);
}
logging_init("udev");
dbg("version %s", UDEV_VERSION);
udev_init_config();
/* set signal handlers */
memset(&act, 0x00, sizeof(act));
act.sa_handler = (void (*) (int))sig_handler;
sigemptyset (&act.sa_mask);
act.sa_flags = 0;
sigaction(SIGALRM, &act, NULL);
sigaction(SIGINT, &act, NULL);
sigaction(SIGTERM, &act, NULL);
/* trigger timeout to prevent hanging processes */
alarm(ALARM_TIMEOUT);
/* let the executed programs know if we handle the whole hotplug event */
managed_event = manage_hotplug_event();
if (managed_event)
setenv("MANAGED_EVENT", "1", 1);
action = getenv("ACTION");
devpath = getenv("DEVPATH");
subsystem = getenv("SUBSYSTEM");
/* older kernels passed the SUBSYSTEM only as argument */
if (!subsystem && argc == 2)
subsystem = argv[1];
udev_init_device(&udev, devpath, subsystem);
if (!action || !subsystem || !devpath) {
dbg("action, subsystem or devpath missing");
goto hotplug;
}
/* export logging flag, as called scripts may want to do the same as udev */
if (udev_log)
setenv("UDEV_LOG", "1", 1);
if (udev.type == DEV_BLOCK || udev.type == DEV_CLASS || udev.type == DEV_NET) {
if (strcmp(action, "add") == 0) {
/* wait for sysfs and possibly add node */
dbg("udev add");
/* skip subsystems without "dev", but handle net devices */
if (udev.type != DEV_NET && subsystem_expect_no_dev(udev.subsystem)) {
dbg("don't care about '%s' devices", udev.subsystem);
goto hotplug;
}
snprintf(path, sizeof(path), "%s%s", sysfs_path, udev.devpath);
path[sizeof(path)-1] = '\0';
class_dev = wait_class_device_open(path);
if (class_dev == NULL) {
dbg ("open class device failed");
goto hotplug;
}
dbg("opened class_dev->name='%s'", class_dev->name);
wait_for_class_device(class_dev, &error);
/* init rules */
udev_rules_init();
/* name, create node, store in db */
retval = udev_add_device(&udev, class_dev);
sysfs_close_class_device(class_dev);
} else if (strcmp(action, "remove") == 0) {
/* possibly remove a node */
dbg("udev remove");
/* skip subsystems without "dev" */
if (subsystem_expect_no_dev(udev.subsystem)) {
dbg("don't care about '%s' devices", udev.subsystem);
goto hotplug;
}
/* get node from db, remove db-entry, delete created node */
retval = udev_remove_device(&udev);
}
/* run dev.d/ scripts if we created/deleted a node or changed a netif name */
if (udev.devname[0] != '\0') {
setenv("DEVNAME", udev.devname, 1);
if (udev_dev_d)
udev_multiplex_directory(&udev, DEVD_DIR, DEVD_SUFFIX);
}
} else if (udev.type == DEV_DEVICE) {
if (strcmp(action, "add") == 0) {
/* wait for sysfs */
dbg("devices add");
snprintf(path, sizeof(path), "%s%s", sysfs_path, devpath);
path[sizeof(path)-1] = '\0';
devices_dev = wait_devices_device_open(path);
if (!devices_dev) {
dbg("devices device unavailable (probably remove has beaten us)");
goto hotplug;
}
dbg("devices device opened '%s'", path);
wait_for_devices_device(devices_dev, &error);
sysfs_close_device(devices_dev);
} else if (strcmp(action, "remove") == 0) {
dbg("devices remove");
}
} else {
dbg("unhandled");
}
hotplug:
udev_cleanup_device(&udev);
if (udev_hotplug_d && managed_event)
udev_multiplex_directory(&udev, HOTPLUGD_DIR, HOTPLUG_SUFFIX);
logging_close();
return retval;
}