1/*
2 * edd_id - naming of BIOS disk devices via EDD
3 *
4 * Copyright (C) 2005 John Hull <John_Hull@Dell.com>
5 * Copyright (C) 2005 Kay Sievers <kay.sievers@vrfy.org>
6 *
7 *	This program is free software; you can redistribute it and/or modify it
8 *	under the terms of the GNU General Public License as published by the
9 *	Free Software Foundation version 2 of the License.
10 */
11
12#ifndef _GNU_SOURCE
13#define _GNU_SOURCE 1
14#endif
15
16#include <stdio.h>
17#include <stdlib.h>
18#include <unistd.h>
19#include <fcntl.h>
20#include <ctype.h>
21#include <string.h>
22#include <errno.h>
23#include <dirent.h>
24#include <stdint.h>
25
26#include "../../udev.h"
27
28#ifdef USE_LOG
29void log_message(int priority, const char *format, ...)
30{
31	va_list args;
32	static int udev_log = -1;
33
34	if (udev_log == -1) {
35		const char *value;
36
37		value = getenv("UDEV_LOG");
38		if (value)
39			udev_log = log_priority(value);
40		else
41			udev_log = LOG_ERR;
42	}
43
44	if (priority > udev_log)
45		return;
46
47	va_start(args, format);
48	vsyslog(priority, format, args);
49	va_end(args);
50}
51#endif
52
53int main(int argc, char *argv[])
54{
55	const char *node = NULL;
56	int i;
57	int export = 0;
58	uint32_t disk_id;
59	uint16_t mbr_valid;
60	struct dirent *dent;
61	int disk_fd;
62	int sysfs_fd;
63	DIR *dir = NULL;
64	int rc = 1;
65	char match[NAME_MAX] = "";
66
67	logging_init("edd_id");
68
69	for (i = 1 ; i < argc; i++) {
70		char *arg = argv[i];
71
72		if (strcmp(arg, "--export") == 0) {
73			export = 1;
74		} else
75			node = arg;
76	}
77	if (node == NULL) {
78		err("no node specified");
79		fprintf(stderr, "no node specified\n");
80		goto exit;
81	}
82
83	/* check for kernel support */
84	dir = opendir("/sys/firmware/edd");
85	if (dir == NULL) {
86		info("no kernel EDD support");
87		fprintf(stderr, "no kernel EDD support\n");
88		rc = 2;
89		goto exit;
90	}
91
92	disk_fd = open(node, O_RDONLY);
93	if (disk_fd < 0) {
94		info("unable to open '%s'", node);
95		fprintf(stderr, "unable to open '%s'\n", node);
96		rc = 3;
97		goto closedir;
98	}
99
100	/* check for valid MBR signature */
101	if (lseek(disk_fd, 510, SEEK_SET) < 0) {
102		info("seek to MBR validity failed '%s'", node);
103		rc = 4;
104		goto close;
105	}
106	if (read(disk_fd, &mbr_valid, sizeof(mbr_valid)) != sizeof(mbr_valid)) {
107		info("read MBR validity failed '%s'", node);
108		rc = 5;
109		goto close;
110	}
111	if (mbr_valid != 0xAA55) {
112		fprintf(stderr, "no valid MBR signature '%s'\n", node);
113		info("no valid MBR signature '%s'", node);
114		rc=6;
115		goto close;
116	}
117
118	/* read EDD signature */
119	if (lseek(disk_fd, 440, SEEK_SET) < 0) {
120		info("seek to signature failed '%s'", node);
121		rc = 7;
122		goto close;
123	}
124	if (read(disk_fd, &disk_id, sizeof(disk_id)) != sizeof(disk_id)) {
125		info("read signature failed '%s'", node);
126		rc = 8;
127		goto close;
128	}
129	/* all zero is invalid */
130	info("read id 0x%08x from '%s'", disk_id, node);
131	if (disk_id == 0) {
132		fprintf(stderr, "no EDD signature '%s'\n", node);
133		info("'%s' signature is zero", node);
134		rc = 9;
135		goto close;
136	}
137
138	/* lookup signature in sysfs to determine the name */
139	for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
140		char file[PATH_SIZE];
141		char sysfs_id_buf[256];
142		uint32_t sysfs_id;
143		ssize_t size;
144
145		if (dent->d_name[0] == '.')
146			continue;
147
148		snprintf(file, sizeof(file), "/sys/firmware/edd/%s/mbr_signature", dent->d_name);
149		file[sizeof(file)-1] = '\0';
150
151		sysfs_fd = open(file, O_RDONLY);
152		if (sysfs_fd < 0) {
153			info("unable to open sysfs '%s'", file);
154			continue;
155		}
156
157		size = read(sysfs_fd, sysfs_id_buf, sizeof(sysfs_id_buf)-1);
158		close(sysfs_fd);
159		if (size <= 0) {
160			info("read sysfs '%s' failed", file);
161			continue;
162		}
163		sysfs_id_buf[size] = '\0';
164		info("read '%s' from '%s'", sysfs_id_buf, file);
165		sysfs_id = strtoul(sysfs_id_buf, NULL, 16);
166
167		/* look for matching value, that appears only once */
168		if (disk_id == sysfs_id) {
169			if (match[0] == '\0') {
170				/* store id */
171				strlcpy(match, dent->d_name, sizeof(match));
172			} else {
173				/* error, same signature for another device */
174				info("'%s' does not have a unique signature", node);
175				fprintf(stderr, "'%s' does not have a unique signature\n", node);
176				rc = 10;
177				goto exit;
178			}
179		}
180	}
181
182	if (match[0] != '\0') {
183		if (export)
184			printf("ID_EDD=%s\n", match);
185		else
186			printf("%s\n", match);
187		rc = 0;
188	}
189
190close:
191	close(disk_fd);
192closedir:
193	closedir(dir);
194exit:
195	logging_close();
196	return rc;
197}
198