systemd/udev_remove.c

/*
 * udev-remove.c
 *
 * Userspace devfs
 *
 * Copyright (C) 2003 Greg Kroah-Hartman <greg@kroah.com>
 *
 *
 *	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 <stdlib.h>
#include <string.h>
#include <stddef.h>
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <sys/stat.h>

#include "udev_libc_wrapper.h"
#include "udev.h"
#include "udev_utils.h"
#include "udev_version.h"
#include "udev_db.h"
#include "logging.h"

static int delete_path(const char *path)
{
	char *pos;
	int retval;

	pos = strrchr(path, '/');
	while (1) {
		*pos = '\0';
		pos = strrchr(path, '/');

		/* don't remove the last one */
		if ((pos == path) || (pos == NULL))
			break;

		/* remove if empty */
		retval = rmdir(path);
		if (errno == ENOENT)
			retval = 0;
		if (retval) {
			if (errno == ENOTEMPTY)
				return 0;
			dbg("rmdir(%s) failed with error '%s'",
			    path, strerror(errno));
			break;
		}
		dbg("removed '%s'", path);
	}
	return 0;
}

static int delete_node(struct udevice *udev)
{
	char filename[PATH_SIZE];
	char partitionname[PATH_SIZE];
	struct name_entry *name_loop;
	struct stat stats;
	int retval;
	int i;
	int num;

	list_for_each_entry(name_loop, &udev->symlink_list, node) {
		snprintf(filename, sizeof(filename), "%s/%s", udev_root, name_loop->name);
		filename[sizeof(filename)-1] = '\0';

		if (stat(filename, &stats) != 0) {
			dbg("symlink '%s' not found", filename);
			continue;
		}
		if (udev->devt && stats.st_rdev != udev->devt) {
			info("symlink '%s' points to a different device, skip removal", filename);
			continue;;
		}

		dbg("removing symlink '%s'", filename);
		unlink(filename);

		if (strchr(filename, '/'))
			delete_path(filename);
	}

	snprintf(filename, sizeof(filename), "%s/%s", udev_root, udev->name);
	filename[sizeof(filename)-1] = '\0';

	if (stat(filename, &stats) != 0) {
		dbg("device node '%s' not found", filename);
		return -1;
	}
	if (udev->devt && stats.st_rdev != udev->devt) {
		info("device node '%s' points to a different device, skip removal", filename);
		return -1;
	}

	info("removing device node '%s'", filename);
	retval = unlink_secure(filename);
	if (retval)
		return retval;

	num = udev->partitions;
	if (num > 0) {
		info("removing all_partitions '%s[1-%i]'", filename, num);
		if (num > 255) {
			info("garbage from udev database, skip all_partitions removal");
			return -1;
		}
		for (i = 1; i <= num; i++) {
			snprintf(partitionname, sizeof(partitionname), "%s%d", filename, i);
			partitionname[sizeof(partitionname)-1] = '\0';
			unlink_secure(partitionname);
		}
	}

	if (strchr(udev->name, '/'))
		delete_path(filename);

	return retval;
}

/*
 * look up the sysfs path in the database to get the node name to remove
 * If we can't find it, use kernel name for lack of anything else to know to do
 */
int udev_remove_device(struct udevice *udev)
{
	const char *temp;

	if (udev->type != DEV_BLOCK && udev->type != DEV_CLASS)
		return 0;

	if (udev_db_get_device(udev, udev->devpath) == 0) {
		if (udev->ignore_remove) {
			dbg("remove event for '%s' requested to be ignored by rule", udev->name);
			return 0;
		}
		dbg("remove name='%s'", udev->name);
		udev_db_delete_device(udev);
	} else {
		/* fall back to kernel name */
		temp = strrchr(udev->devpath, '/');
		if (temp == NULL)
			return -ENODEV;
		strlcpy(udev->name, &temp[1], sizeof(udev->name));
		info("'%s' not found in database, falling back on default name", udev->name);
	}

	/* use full path to the environment */
	snprintf(udev->devname, sizeof(udev->devname), "%s/%s", udev_root, udev->name);
	udev->devname[sizeof(udev->devname)-1] = '\0';

	return delete_node(udev);
}