edd_id.c revision ad29a9f14fa8b1932c0e418bfcf1c10ce6a35a33
/*
* edd_id - naming of BIOS disk devices via EDD
*
* Copyright (C) 2005 John Hull <John_Hull@Dell.com>
* Copyright (C) 2005 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, 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/>.
*/
#ifndef _GNU_SOURCE
#define _GNU_SOURCE 1
#endif
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <ctype.h>
#include <string.h>
#include <errno.h>
#include <dirent.h>
#include <stdint.h>
#include "libudev.h"
#include "libudev-private.h"
static void log_fn(struct udev *udev, int priority,
const char *file, int line, const char *fn,
const char *format, va_list args)
{
vsyslog(priority, format, args);
}
int main(int argc, char *argv[])
{
struct udev *udev;
const char *node = NULL;
int i;
int export = 0;
uint32_t disk_id;
uint16_t mbr_valid;
struct dirent *dent;
int disk_fd;
int sysfs_fd;
DIR *dir = NULL;
int rc = 1;
char filename[UTIL_PATH_SIZE];
char match[UTIL_PATH_SIZE];
udev = udev_new();
if (udev == NULL)
goto exit;
udev_log_init("edd_id");
udev_set_log_fn(udev, log_fn);
for (i = 1 ; i < argc; i++) {
char *arg = argv[i];
if (strcmp(arg, "--export") == 0) {
export = 1;
} else
node = arg;
}
if (node == NULL) {
err(udev, "no node specified\n");
fprintf(stderr, "no node specified\n");
goto exit;
}
/* check for kernel support */
util_strscpyl(filename, sizeof(filename), udev_get_sys_path(udev), "/firmware/edd", NULL);
dir = opendir(filename);
if (dir == NULL) {
info(udev, "no kernel EDD support\n");
fprintf(stderr, "no kernel EDD support\n");
rc = 2;
goto exit;
}
disk_fd = open(node, O_RDONLY);
if (disk_fd < 0) {
info(udev, "unable to open '%s'\n", node);
fprintf(stderr, "unable to open '%s'\n", node);
rc = 3;
goto closedir;
}
/* check for valid MBR signature */
if (lseek(disk_fd, 510, SEEK_SET) < 0) {
info(udev, "seek to MBR validity failed '%s'\n", node);
rc = 4;
goto close;
}
if (read(disk_fd, &mbr_valid, sizeof(mbr_valid)) != sizeof(mbr_valid)) {
info(udev, "read MBR validity failed '%s'\n", node);
rc = 5;
goto close;
}
if (mbr_valid != 0xAA55) {
fprintf(stderr, "no valid MBR signature '%s'\n", node);
info(udev, "no valid MBR signature '%s'\n", node);
rc=6;
goto close;
}
/* read EDD signature */
if (lseek(disk_fd, 440, SEEK_SET) < 0) {
info(udev, "seek to signature failed '%s'\n", node);
rc = 7;
goto close;
}
if (read(disk_fd, &disk_id, sizeof(disk_id)) != sizeof(disk_id)) {
info(udev, "read signature failed '%s'\n", node);
rc = 8;
goto close;
}
/* all zero is invalid */
info(udev, "read id 0x%08x from '%s'\n", disk_id, node);
if (disk_id == 0) {
fprintf(stderr, "no EDD signature '%s'\n", node);
info(udev, "'%s' signature is zero\n", node);
rc = 9;
goto close;
}
/* lookup signature in sysfs to determine the name */
match[0] = '\0';
for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
char sysfs_id_buf[256];
uint32_t sysfs_id;
ssize_t size;
if (dent->d_name[0] == '.')
continue;
util_strscpyl(filename, sizeof(filename), dent->d_name, "/mbr_signature", NULL);
sysfs_fd = openat(dirfd(dir), filename, O_RDONLY);
if (sysfs_fd < 0) {
info(udev, "unable to open sysfs '%s'\n", filename);
continue;
}
size = read(sysfs_fd, sysfs_id_buf, sizeof(sysfs_id_buf)-1);
close(sysfs_fd);
if (size <= 0) {
info(udev, "read sysfs '%s' failed\n", filename);
continue;
}
sysfs_id_buf[size] = '\0';
info(udev, "read '%s' from '%s'\n", sysfs_id_buf, filename);
sysfs_id = strtoul(sysfs_id_buf, NULL, 16);
/* look for matching value, that appears only once */
if (disk_id == sysfs_id) {
if (match[0] == '\0') {
/* store id */
util_strscpy(match, sizeof(match), dent->d_name);
} else {
/* error, same signature for another device */
info(udev, "'%s' does not have a unique signature\n", node);
fprintf(stderr, "'%s' does not have a unique signature\n", node);
rc = 10;
goto exit;
}
}
}
if (match[0] != '\0') {
if (export)
printf("ID_EDD=%s\n", match);
else
printf("%s\n", match);
rc = 0;
}
close:
close(disk_fd);
closedir:
closedir(dir);
exit:
udev_unref(udev);
udev_log_close();
return rc;
}