cgpt_boot.c revision fa6b35c1ffa33833b3250a6515869ccd4cb59121 
1// Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#include <errno.h>
6#include <fcntl.h>
7#include <string.h>
8#include <unistd.h>
9
10#include "cgpt.h"
11#include "cgpt_params.h"
12#include "cgptlib_internal.h"
13#include "endian.h"
14#include "vboot_host.h"
15
16int CgptGetBootPartitionNumber(CgptBootParams *params) {
17  struct drive drive;
18  int gpt_retval= 0;
19  int retval;
20
21  if (params == NULL)
22    return CGPT_FAILED;
23
24  if (CGPT_OK != DriveOpen(params->drive_name, &drive, O_RDONLY))
25    return CGPT_FAILED;
26
27  if (GPT_SUCCESS != (gpt_retval = GptSanityCheck(&drive.gpt))) {
28    Error("GptSanityCheck() returned %d: %s\n",
29          gpt_retval, GptError(gpt_retval));
30    retval = CGPT_FAILED;
31    goto done;
32  }
33
34  if (CGPT_OK != ReadPMBR(&drive)) {
35    Error("Unable to read PMBR\n");
36    retval = CGPT_FAILED;
37    goto done;
38  }
39
40  char buf[GUID_STRLEN];
41  GuidToStr(&drive.pmbr.boot_guid, buf, sizeof(buf));
42
43  int numEntries = GetNumberOfEntries(&drive);
44  int i;
45  for(i = 0; i < numEntries; i++) {
46      GptEntry *entry = GetEntry(&drive.gpt, ANY_VALID, i);
47
48      if (GuidEqual(&entry->unique, &drive.pmbr.boot_guid)) {
49        params->partition = i + 1;
50        retval = CGPT_OK;
51        goto done;
52      }
53  }
54
55  Error("Didn't find any boot partition\n");
56  params->partition = 0;
57  retval = CGPT_FAILED;
58
59done:
60  (void) DriveClose(&drive, 1);
61  return retval;
62}
63
64
65int CgptBoot(CgptBootParams *params) {
66  struct drive drive;
67  int retval = 1;
68  int gpt_retval= 0;
69  int mode = O_RDONLY;
70
71  if (params == NULL)
72    return CGPT_FAILED;
73
74  if (params->create_pmbr || params->partition || params->bootfile)
75    mode = O_RDWR;
76
77  if (CGPT_OK != DriveOpen(params->drive_name, &drive, mode)) {
78    return CGPT_FAILED;
79  }
80
81  if (CGPT_OK != ReadPMBR(&drive)) {
82    Error("Unable to read PMBR\n");
83    goto done;
84  }
85
86  if (params->create_pmbr) {
87    drive.pmbr.magic[0] = 0x1d;
88    drive.pmbr.magic[1] = 0x9a;
89    drive.pmbr.sig[0] = 0x55;
90    drive.pmbr.sig[1] = 0xaa;
91    memset(&drive.pmbr.part, 0, sizeof(drive.pmbr.part));
92    drive.pmbr.part[0].f_head = 0x00;
93    drive.pmbr.part[0].f_sect = 0x02;
94    drive.pmbr.part[0].f_cyl = 0x00;
95    drive.pmbr.part[0].type = 0xee;
96    drive.pmbr.part[0].l_head = 0xff;
97    drive.pmbr.part[0].l_sect = 0xff;
98    drive.pmbr.part[0].l_cyl = 0xff;
99    drive.pmbr.part[0].f_lba = htole32(1);
100    uint32_t max = 0xffffffff;
101    if (drive.gpt.drive_sectors < 0xffffffff)
102      max = drive.gpt.drive_sectors - 1;
103    drive.pmbr.part[0].num_sect = htole32(max);
104  }
105
106  if (params->partition) {
107    if (GPT_SUCCESS != (gpt_retval = GptSanityCheck(&drive.gpt))) {
108      Error("GptSanityCheck() returned %d: %s\n",
109            gpt_retval, GptError(gpt_retval));
110      goto done;
111    }
112
113    if (params->partition > GetNumberOfEntries(&drive)) {
114      Error("invalid partition number: %d\n", params->partition);
115      goto done;
116    }
117
118    uint32_t index = params->partition - 1;
119    GptEntry *entry = GetEntry(&drive.gpt, ANY_VALID, index);
120    memcpy(&drive.pmbr.boot_guid, &entry->unique, sizeof(Guid));
121  }
122
123  if (params->bootfile) {
124    int fd = open(params->bootfile, O_RDONLY);
125    if (fd < 0) {
126      Error("Can't read %s: %s\n", params->bootfile, strerror(errno));
127      goto done;
128    }
129
130    int n = read(fd, drive.pmbr.bootcode, sizeof(drive.pmbr.bootcode));
131    if (n < 1) {
132      Error("problem reading %s: %s\n", params->bootfile, strerror(errno));
133      close(fd);
134      goto done;
135    }
136
137    close(fd);
138  }
139
140  char buf[GUID_STRLEN];
141  GuidToStr(&drive.pmbr.boot_guid, buf, sizeof(buf));
142  printf("%s\n", buf);
143
144  // Write it all out, if needed.
145  if (mode == O_RDONLY || CGPT_OK == WritePMBR(&drive))
146    retval = 0;
147
148done:
149  (void) DriveClose(&drive, 1);
150  return retval;
151}
152