1/*-
2 * Copyright (c) 2010 Pawel Jakub Dawidek <pjd@FreeBSD.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27#include <sys/cdefs.h>
28__FBSDID("$FreeBSD$");
29
30#include <sys/param.h>
31#include <sys/gpt.h>
32
33#ifndef LITTLE_ENDIAN
34#error gpt.c works only for little endian architectures
35#endif
36
37#include "crc32.h"
38#include "drv.h"
39#include "util.h"
40#include "gpt.h"
41
42#define	MAXTBLENTS	128
43
44static struct gpt_hdr hdr_primary, hdr_backup, *gpthdr;
45static uint64_t hdr_primary_lba, hdr_backup_lba;
46static struct gpt_ent table_primary[MAXTBLENTS], table_backup[MAXTBLENTS];
47static struct gpt_ent *gpttable;
48static int curent, bootonce;
49
50/*
51 * Buffer below 64kB passed on gptread(), which can hold at least
52 * one sector of data (512 bytes).
53 */
54static char *secbuf;
55
56static void
57gptupdate(const char *which, struct dsk *dskp, struct gpt_hdr *hdr,
58    struct gpt_ent *table)
59{
60	int entries_per_sec, firstent;
61	daddr_t slba;
62
63	/*
64	 * We need to update the following for both primary and backup GPT:
65	 * 1. Sector on disk that contains current partition.
66	 * 2. Partition table checksum.
67	 * 3. Header checksum.
68	 * 4. Header on disk.
69	 */
70
71	entries_per_sec = DEV_BSIZE / hdr->hdr_entsz;
72	slba = curent / entries_per_sec;
73	firstent = slba * entries_per_sec;
74	bcopy(&table[firstent], secbuf, DEV_BSIZE);
75	slba += hdr->hdr_lba_table;
76	if (drvwrite(dskp, secbuf, slba, 1)) {
77		printf("%s: unable to update %s GPT partition table\n",
78		    BOOTPROG, which);
79		return;
80	}
81	hdr->hdr_crc_table = crc32(table, hdr->hdr_entries * hdr->hdr_entsz);
82	hdr->hdr_crc_self = 0;
83	hdr->hdr_crc_self = crc32(hdr, hdr->hdr_size);
84	bzero(secbuf, DEV_BSIZE);
85	bcopy(hdr, secbuf, hdr->hdr_size);
86	if (drvwrite(dskp, secbuf, hdr->hdr_lba_self, 1)) {
87		printf("%s: unable to update %s GPT header\n", BOOTPROG, which);
88		return;
89	}
90}
91
92int
93gptfind(const uuid_t *uuid, struct dsk *dskp, int part)
94{
95	struct gpt_ent *ent;
96	int firsttry;
97
98	if (part >= 0) {
99		if (part == 0 || part > gpthdr->hdr_entries) {
100			printf("%s: invalid partition index\n", BOOTPROG);
101			return (-1);
102		}
103		ent = &gpttable[part - 1];
104		if (bcmp(&ent->ent_type, uuid, sizeof(uuid_t)) != 0) {
105			printf("%s: specified partition is not UFS\n",
106			    BOOTPROG);
107			return (-1);
108		}
109		curent = part - 1;
110		goto found;
111	}
112
113	firsttry = (curent == -1);
114	curent++;
115	if (curent >= gpthdr->hdr_entries) {
116		curent = gpthdr->hdr_entries;
117		return (-1);
118	}
119	if (bootonce) {
120		/*
121		 * First look for partition with both GPT_ENT_ATTR_BOOTME and
122		 * GPT_ENT_ATTR_BOOTONCE flags.
123		 */
124		for (; curent < gpthdr->hdr_entries; curent++) {
125			ent = &gpttable[curent];
126			if (bcmp(&ent->ent_type, uuid, sizeof(uuid_t)) != 0)
127				continue;
128			if (!(ent->ent_attr & GPT_ENT_ATTR_BOOTME))
129				continue;
130			if (!(ent->ent_attr & GPT_ENT_ATTR_BOOTONCE))
131				continue;
132			/* Ok, found one. */
133			goto found;
134		}
135		bootonce = 0;
136		curent = 0;
137	}
138	for (; curent < gpthdr->hdr_entries; curent++) {
139		ent = &gpttable[curent];
140		if (bcmp(&ent->ent_type, uuid, sizeof(uuid_t)) != 0)
141			continue;
142		if (!(ent->ent_attr & GPT_ENT_ATTR_BOOTME))
143			continue;
144		if (ent->ent_attr & GPT_ENT_ATTR_BOOTONCE)
145			continue;
146		/* Ok, found one. */
147		goto found;
148	}
149	if (firsttry) {
150		/*
151		 * No partition with BOOTME flag was found, try to boot from
152		 * first UFS partition.
153		 */
154		for (curent = 0; curent < gpthdr->hdr_entries; curent++) {
155			ent = &gpttable[curent];
156			if (bcmp(&ent->ent_type, uuid, sizeof(uuid_t)) != 0)
157				continue;
158			/* Ok, found one. */
159			goto found;
160		}
161	}
162	return (-1);
163found:
164	dskp->part = curent + 1;
165	ent = &gpttable[curent];
166	dskp->start = ent->ent_lba_start;
167	if (ent->ent_attr & GPT_ENT_ATTR_BOOTONCE) {
168		/*
169		 * Clear BOOTME, but leave BOOTONCE set before trying to
170		 * boot from this partition.
171		 */
172		if (hdr_primary_lba > 0) {
173			table_primary[curent].ent_attr &= ~GPT_ENT_ATTR_BOOTME;
174			gptupdate("primary", dskp, &hdr_primary, table_primary);
175		}
176		if (hdr_backup_lba > 0) {
177			table_backup[curent].ent_attr &= ~GPT_ENT_ATTR_BOOTME;
178			gptupdate("backup", dskp, &hdr_backup, table_backup);
179		}
180	}
181	return (0);
182}
183
184static int
185gptread_hdr(const char *which, struct dsk *dskp, struct gpt_hdr *hdr,
186    uint64_t hdrlba)
187{
188	uint32_t crc;
189
190	if (drvread(dskp, secbuf, hdrlba, 1)) {
191		printf("%s: unable to read %s GPT header\n", BOOTPROG, which);
192		return (-1);
193	}
194	bcopy(secbuf, hdr, sizeof(*hdr));
195	if (bcmp(hdr->hdr_sig, GPT_HDR_SIG, sizeof(hdr->hdr_sig)) != 0 ||
196	    hdr->hdr_lba_self != hdrlba || hdr->hdr_revision < 0x00010000 ||
197	    hdr->hdr_entsz < sizeof(struct gpt_ent) ||
198	    hdr->hdr_entries > MAXTBLENTS || DEV_BSIZE % hdr->hdr_entsz != 0) {
199		printf("%s: invalid %s GPT header\n", BOOTPROG, which);
200		return (-1);
201	}
202	crc = hdr->hdr_crc_self;
203	hdr->hdr_crc_self = 0;
204	if (crc32(hdr, hdr->hdr_size) != crc) {
205		printf("%s: %s GPT header checksum mismatch\n", BOOTPROG,
206		    which);
207		return (-1);
208	}
209	hdr->hdr_crc_self = crc;
210	return (0);
211}
212
213void
214gptbootfailed(struct dsk *dskp)
215{
216
217	if (!(gpttable[curent].ent_attr & GPT_ENT_ATTR_BOOTONCE))
218		return;
219
220	if (hdr_primary_lba > 0) {
221		table_primary[curent].ent_attr &= ~GPT_ENT_ATTR_BOOTONCE;
222		table_primary[curent].ent_attr |= GPT_ENT_ATTR_BOOTFAILED;
223		gptupdate("primary", dskp, &hdr_primary, table_primary);
224	}
225	if (hdr_backup_lba > 0) {
226		table_backup[curent].ent_attr &= ~GPT_ENT_ATTR_BOOTONCE;
227		table_backup[curent].ent_attr |= GPT_ENT_ATTR_BOOTFAILED;
228		gptupdate("backup", dskp, &hdr_backup, table_backup);
229	}
230}
231
232static void
233gptbootconv(const char *which, struct dsk *dskp, struct gpt_hdr *hdr,
234    struct gpt_ent *table)
235{
236	struct gpt_ent *ent;
237	daddr_t slba;
238	int table_updated, sector_updated;
239	int entries_per_sec, nent, part;
240
241	table_updated = 0;
242	entries_per_sec = DEV_BSIZE / hdr->hdr_entsz;
243	for (nent = 0, slba = hdr->hdr_lba_table;
244	     slba < hdr->hdr_lba_table + hdr->hdr_entries / entries_per_sec;
245	     slba++, nent += entries_per_sec) {
246		sector_updated = 0;
247		for (part = 0; part < entries_per_sec; part++) {
248			ent = &table[nent + part];
249			if ((ent->ent_attr & (GPT_ENT_ATTR_BOOTME |
250			    GPT_ENT_ATTR_BOOTONCE |
251			    GPT_ENT_ATTR_BOOTFAILED)) !=
252			    GPT_ENT_ATTR_BOOTONCE) {
253				continue;
254			}
255			ent->ent_attr &= ~GPT_ENT_ATTR_BOOTONCE;
256			ent->ent_attr |= GPT_ENT_ATTR_BOOTFAILED;
257			table_updated = 1;
258			sector_updated = 1;
259		}
260		if (!sector_updated)
261			continue;
262		bcopy(&table[nent], secbuf, DEV_BSIZE);
263		if (drvwrite(dskp, secbuf, slba, 1)) {
264			printf("%s: unable to update %s GPT partition table\n",
265			    BOOTPROG, which);
266		}
267	}
268	if (!table_updated)
269		return;
270	hdr->hdr_crc_table = crc32(table, hdr->hdr_entries * hdr->hdr_entsz);
271	hdr->hdr_crc_self = 0;
272	hdr->hdr_crc_self = crc32(hdr, hdr->hdr_size);
273	bzero(secbuf, DEV_BSIZE);
274	bcopy(hdr, secbuf, hdr->hdr_size);
275	if (drvwrite(dskp, secbuf, hdr->hdr_lba_self, 1))
276		printf("%s: unable to update %s GPT header\n", BOOTPROG, which);
277}
278
279static int
280gptread_table(const char *which, const uuid_t *uuid, struct dsk *dskp,
281    struct gpt_hdr *hdr, struct gpt_ent *table)
282{
283	struct gpt_ent *ent;
284	int entries_per_sec;
285	int part, nent;
286	daddr_t slba;
287
288	if (hdr->hdr_entries == 0)
289		return (0);
290
291	entries_per_sec = DEV_BSIZE / hdr->hdr_entsz;
292	slba = hdr->hdr_lba_table;
293	nent = 0;
294	for (;;) {
295		if (drvread(dskp, secbuf, slba, 1)) {
296			printf("%s: unable to read %s GPT partition table\n",
297			    BOOTPROG, which);
298			return (-1);
299		}
300		ent = (struct gpt_ent *)secbuf;
301		for (part = 0; part < entries_per_sec; part++, ent++) {
302			bcopy(ent, &table[nent], sizeof(table[nent]));
303			if (++nent >= hdr->hdr_entries)
304				break;
305		}
306		if (nent >= hdr->hdr_entries)
307			break;
308		slba++;
309	}
310	if (crc32(table, nent * hdr->hdr_entsz) != hdr->hdr_crc_table) {
311		printf("%s: %s GPT table checksum mismatch\n", BOOTPROG, which);
312		return (-1);
313	}
314	return (0);
315}
316
317int
318gptread(const uuid_t *uuid, struct dsk *dskp, char *buf)
319{
320	uint64_t altlba;
321
322	/*
323	 * Read and verify both GPT headers: primary and backup.
324	 */
325
326	secbuf = buf;
327	hdr_primary_lba = hdr_backup_lba = 0;
328	curent = -1;
329	bootonce = 1;
330	dskp->start = 0;
331
332	if (gptread_hdr("primary", dskp, &hdr_primary, 1) == 0 &&
333	    gptread_table("primary", uuid, dskp, &hdr_primary,
334	    table_primary) == 0) {
335		hdr_primary_lba = hdr_primary.hdr_lba_self;
336		gpthdr = &hdr_primary;
337		gpttable = table_primary;
338	}
339
340	if (hdr_primary_lba > 0) {
341		/*
342		 * If primary header is valid, we can get backup
343		 * header location from there.
344		 */
345		altlba = hdr_primary.hdr_lba_alt;
346	} else {
347		altlba = drvsize(dskp);
348		if (altlba > 0)
349			altlba--;
350	}
351	if (altlba == 0)
352		printf("%s: unable to locate backup GPT header\n", BOOTPROG);
353	else if (gptread_hdr("backup", dskp, &hdr_backup, altlba) == 0 &&
354	    gptread_table("backup", uuid, dskp, &hdr_backup,
355	    table_backup) == 0) {
356		hdr_backup_lba = hdr_backup.hdr_lba_self;
357		if (hdr_primary_lba == 0) {
358			gpthdr = &hdr_backup;
359			gpttable = table_backup;
360			printf("%s: using backup GPT\n", BOOTPROG);
361		}
362	}
363
364	/*
365	 * Convert all BOOTONCE without BOOTME flags into BOOTFAILED.
366	 * BOOTONCE without BOOTME means that we tried to boot from it,
367	 * but failed after leaving gptboot and machine was rebooted.
368	 * We don't want to leave partitions marked as BOOTONCE only,
369	 * because when we boot successfully start-up scripts should
370	 * find at most one partition with only BOOTONCE flag and this
371	 * will mean that we booted from that partition.
372	 */
373	if (hdr_primary_lba != 0)
374		gptbootconv("primary", dskp, &hdr_primary, table_primary);
375	if (hdr_backup_lba != 0)
376		gptbootconv("backup", dskp, &hdr_backup, table_backup);
377
378	if (hdr_primary_lba == 0 && hdr_backup_lba == 0)
379		return (-1);
380	return (0);
381}
382