Systemd/udevdb.c

/*
 * udevdb.c
 *
 * Userspace devfs
 *
 * Copyright (C) 2003 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 <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <stddef.h>
#include <fcntl.h>
#include <string.h>
#include <errno.h>
#include <dirent.h>

#include "libsysfs/sysfs/libsysfs.h"
#include "udev.h"
#include "udev_lib.h"
#include "logging.h"
#include "udevdb.h"

#define PATH_TO_NAME_CHAR		'@'

static int get_db_filename(struct udevice *udev, char *filename, int len)
{
	char devpath[SYSFS_PATH_MAX];
	char *pos;

	/* replace '/' to transform path into a filename */
	strfieldcpy(devpath, udev->devpath);
	pos = strchr(&devpath[1], '/');
	while (pos) {
		pos[0] = PATH_TO_NAME_CHAR;
		pos = strchr(&pos[1], '/');
	}
	snprintf(filename, len, "%s%s", udev_db_path, devpath);
	filename[len-1] = '\0';

	return 0;
}

int udevdb_add_dev(struct udevice *udev)
{
	char filename[SYSFS_PATH_MAX];
	FILE *f;

	if (udev->test_run)
		return 0;

	get_db_filename(udev, filename, SYSFS_PATH_MAX);

	create_path(filename);

	f = fopen(filename, "w");
	if (f == NULL) {
		dbg("unable to create db file '%s'", filename);
		return -1;
	}
	dbg("storing data for device '%s' in '%s'", udev->devpath, filename);

	fprintf(f, "P:%s\n", udev->devpath);
	fprintf(f, "N:%s\n", udev->name);
	fprintf(f, "S:%s\n", udev->symlink);
	fprintf(f, "A:%d\n", udev->partitions);

	fclose(f);

	return 0;
}

static int parse_db_file(struct udevice *udev, const char *filename)
{
	char line[NAME_SIZE];
	char *bufline;
	char *buf;
	size_t bufsize;
	size_t cur;
	size_t count;

	if (file_map(filename, &buf, &bufsize) != 0) {
		dbg("unable to read db file '%s'", filename);
		return -1;
	}

	cur = 0;
	while (cur < bufsize) {
		count = buf_get_line(buf, bufsize, cur);
		bufline = &buf[cur];
		cur += count+1;

		switch(bufline[0]) {
		case 'P':
			if (count > DEVPATH_SIZE)
				count = DEVPATH_SIZE-1;
			strncpy(udev->devpath, &bufline[2], count-2);
			break;
		case 'N':
			if (count > NAME_SIZE)
				count = NAME_SIZE-1;
			strncpy(udev->name, &bufline[2], count-2);
			break;
		case 'S':
			if (count > NAME_SIZE)
				count = NAME_SIZE-1;
			strncpy(udev->symlink, &bufline[2], count-2);
			break;
		case 'A':
			strfieldcpy(line, &bufline[2]);
			udev->partitions = atoi(line);
			break;
		}
	}

	if (udev->name[0] == '\0')
		return -1;

	return 0;
}

int udevdb_get_dev(struct udevice *udev)
{
	char filename[SYSFS_PATH_MAX];

	get_db_filename(udev, filename, SYSFS_PATH_MAX);

	return parse_db_file(udev, filename);
}

int udevdb_delete_dev(struct udevice *udev)
{
	char filename[SYSFS_PATH_MAX];

	get_db_filename(udev, filename, SYSFS_PATH_MAX);
	unlink(filename);

	return 0;
}

int udevdb_get_dev_byname(struct udevice *udev, const char *name)
{
	struct dirent *ent;
	DIR *dir;
	char filename[NAME_SIZE];
	struct udevice db_udev;

	dir = opendir(udev_db_path);
	if (dir == NULL) {
		dbg("unable to udev db '%s'", udev_db_path);
		return -1;
	}

	while (1) {
		ent = readdir(dir);
		if (ent == NULL || ent->d_name[0] == '\0')
			break;

		if (ent->d_name[0] == '.')
			continue;

		snprintf(filename, NAME_SIZE, "%s/%s", udev_db_path, ent->d_name);
		filename[NAME_SIZE-1] = '\0';

		memset(&db_udev, 0x00, sizeof(struct udevice));
		if (parse_db_file(&db_udev, filename) == 0) {
			char *pos;
			int len;

			if (strncmp(name, db_udev.name, NAME_SIZE) == 0) {
				goto found;
			}

			foreach_strpart(db_udev.symlink, " ", pos, len) {
				if (strncmp(name, pos, len) != 0)
					continue;

				if (len == strlen(name))
					goto found;
			}

		}
	}

	closedir(dir);

	return -1;

found:
	closedir(dir);

	strfieldcpy(udev->devpath, db_udev.devpath);
	strfieldcpy(udev->name, db_udev.name);
	strfieldcpy(udev->symlink, db_udev.symlink);
	udev->partitions = db_udev.partitions;

	return 0;
}