staging: usbip: userspace: utils.c: rewrite modify_match_busid

/*

 * Copyright (C) 2011 matt mooney <mfm@muteddisk.com>

 *               2005-2007 Takahiro Hirofuchi

 *

 * Copyright (C) 2005-2007 Takahiro Hirofuchi

 * 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, either version 2 of the License, or

 * (at your option) any later version.

 *

 * 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, see <http://www.gnu.org/licenses/>.

 */

#include <sysfs/libsysfs.h>

#include <limits.h>

#include <errno.h>

#include <stdio.h>

#include <string.h>

#include <fcntl.h>

#include <libgen.h>

#include <unistd.h>

#include "usbip_common.h"

#include "utils.h"

int modify_match_busid(char *busid, int add)

{

	int fd;

	int ret;

	char bus_type[] = "usb";

	char attr_name[] = "match_busid";

	char buff[SYSFS_BUS_ID_SIZE + 4];

	char sysfs_mntpath[SYSFS_PATH_MAX];

	char match_busid_path[SYSFS_PATH_MAX];

	char match_busid_attr_path[SYSFS_PATH_MAX];

	struct sysfs_attribute *match_busid_attr;

	int rc, ret = 0;

	ret = sysfs_get_mnt_path(sysfs_mntpath, SYSFS_PATH_MAX);

	if (ret < 0) {

		err("sysfs must be mounted");

	if (strnlen(busid, SYSFS_BUS_ID_SIZE) > SYSFS_BUS_ID_SIZE - 1) {

		dbg("busid is too long");

		return -1;

	}

	snprintf(match_busid_path, sizeof(match_busid_path),

		 "%s/%s/usb/%s/%s/match_busid", sysfs_mntpath, SYSFS_BUS_NAME,

		 SYSFS_DRIVERS_NAME, USBIP_HOST_DRV_NAME);

	/* BUS_IS_SIZE includes NULL termination? */

	if (strnlen(busid, SYSFS_BUS_ID_SIZE) > SYSFS_BUS_ID_SIZE - 1) {

		dbg("busid is too long");

	rc = sysfs_get_mnt_path(sysfs_mntpath, SYSFS_PATH_MAX);

	if (rc < 0) {

		err("sysfs must be mounted: %s", strerror(errno));

		return -1;

	}

	fd = open(match_busid_path, O_WRONLY);

	if (fd < 0)

	snprintf(match_busid_attr_path, sizeof(match_busid_attr_path),

		 "%s/%s/%s/%s/%s/%s", sysfs_mntpath, SYSFS_BUS_NAME, bus_type,

		 SYSFS_DRIVERS_NAME, USBIP_HOST_DRV_NAME, attr_name);

	match_busid_attr = sysfs_open_attribute(match_busid_attr_path);

	if (!match_busid_attr) {

		dbg("problem getting match_busid attribute: %s",

		    strerror(errno));

		return -1;

	}

	if (add)

		snprintf(buff, SYSFS_BUS_ID_SIZE + 4, "add %s", busid);

	else

		snprintf(buff, SYSFS_BUS_ID_SIZE + 4, "del %s", busid);

	dbg("write \"%s\" to %s", buff, match_busid_path);

	dbg("write \"%s\" to %s", buff, match_busid_attr->path);

	ret = write(fd, buff, sizeof(buff));

	if (ret < 0) {

		close(fd);

		return -1;

	rc = sysfs_write_attribute(match_busid_attr, buff, sizeof(buff));

	if (rc < 0) {

		dbg("failed to write match_busid: %s", strerror(errno));

		ret = -1;

	}

	close(fd);

	sysfs_close_attribute(match_busid_attr);

	return 0;

	return ret;

}