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
6 #include <string.h>
7
8 #include "cgpt.h"
9 #include "cgptlib_internal.h"
10 #include "vboot_host.h"
11
AllocAndClear(uint8_t ** buf,uint64_t size)12 static void AllocAndClear(uint8_t **buf, uint64_t size) {
13 if (*buf) {
14 memset(*buf, 0, size);
15 } else {
16 *buf = calloc(1, size);
17 if (!*buf) {
18 Error("Cannot allocate %u bytes.\n", size);
19 abort();
20 }
21 }
22 }
23
GptCreate(struct drive * drive,CgptCreateParams * params)24 static int GptCreate(struct drive *drive, CgptCreateParams *params) {
25 // Allocate and/or erase the data.
26 // We cannot assume the GPT headers or entry arrays have been allocated
27 // by GptLoad() because those fields might have failed validation checks.
28 AllocAndClear(&drive->gpt.primary_header,
29 drive->gpt.sector_bytes * GPT_HEADER_SECTORS);
30 AllocAndClear(&drive->gpt.secondary_header,
31 drive->gpt.sector_bytes * GPT_HEADER_SECTORS);
32
33 drive->gpt.modified |= (GPT_MODIFIED_HEADER1 | GPT_MODIFIED_ENTRIES1 |
34 GPT_MODIFIED_HEADER2 | GPT_MODIFIED_ENTRIES2);
35
36 // Initialize a blank set
37 if (!params->zap) {
38 GptHeader *h = (GptHeader *)drive->gpt.primary_header;
39 memcpy(h->signature, GPT_HEADER_SIGNATURE, GPT_HEADER_SIGNATURE_SIZE);
40 h->revision = GPT_HEADER_REVISION;
41 h->size = sizeof(GptHeader);
42 h->my_lba = GPT_PMBR_SECTORS; /* The second sector on drive. */
43 h->alternate_lba = drive->gpt.gpt_drive_sectors - GPT_HEADER_SECTORS;
44 if (CGPT_OK != GenerateGuid(&h->disk_uuid)) {
45 Error("Unable to generate new GUID.\n");
46 return -1;
47 }
48
49 /* Calculate number of entries */
50 h->size_of_entry = sizeof(GptEntry);
51 h->number_of_entries = MAX_NUMBER_OF_ENTRIES;
52 if (drive->gpt.flags & GPT_FLAG_EXTERNAL) {
53 // We might have smaller space for the GPT table. Scale accordingly.
54 //
55 // +------+------------+---------------+-----+--------------+-----------+
56 // | PMBR | Prim. Head | Prim. Entries | ... | Sec. Entries | Sec. Head |
57 // +------+------------+---------------+-----+--------------+-----------+
58 //
59 // Half the size of gpt_drive_sectors must be big enough to hold PMBR +
60 // GPT Header + Entries Table, though the secondary structures do not
61 // contain PMBR.
62 size_t required_headers_size =
63 (GPT_PMBR_SECTORS + GPT_HEADER_SECTORS) * drive->gpt.sector_bytes;
64 size_t min_entries_size = MIN_NUMBER_OF_ENTRIES * h->size_of_entry;
65 size_t required_min_size = required_headers_size + min_entries_size;
66 size_t half_size =
67 (drive->gpt.gpt_drive_sectors / 2) * drive->gpt.sector_bytes;
68 if (half_size < required_min_size) {
69 Error("Not enough space to store GPT structures. Required %d bytes.\n",
70 required_min_size * 2);
71 return -1;
72 }
73 size_t max_entries =
74 (half_size - required_headers_size) / h->size_of_entry;
75 if (h->number_of_entries > max_entries) {
76 h->number_of_entries = max_entries;
77 }
78 }
79
80 /* Then use number of entries to calculate entries_lba. */
81 h->entries_lba = h->my_lba + GPT_HEADER_SECTORS;
82 if (!(drive->gpt.flags & GPT_FLAG_EXTERNAL)) {
83 h->entries_lba += params->padding;
84 h->first_usable_lba = h->entries_lba + CalculateEntriesSectors(h);
85 h->last_usable_lba = (drive->gpt.streaming_drive_sectors - GPT_HEADER_SECTORS -
86 CalculateEntriesSectors(h) - 1);
87 } else {
88 h->first_usable_lba = params->padding;
89 h->last_usable_lba = (drive->gpt.streaming_drive_sectors - 1);
90 }
91
92 size_t entries_size = h->number_of_entries * h->size_of_entry;
93 AllocAndClear(&drive->gpt.primary_entries, entries_size);
94 AllocAndClear(&drive->gpt.secondary_entries, entries_size);
95
96 // Copy to secondary
97 RepairHeader(&drive->gpt, MASK_PRIMARY);
98
99 UpdateCrc(&drive->gpt);
100 }
101
102 return 0;
103 }
104
CgptCreate(CgptCreateParams * params)105 int CgptCreate(CgptCreateParams *params) {
106 struct drive drive;
107
108 if (params == NULL)
109 return CGPT_FAILED;
110
111 if (CGPT_OK != DriveOpen(params->drive_name, &drive, O_RDWR,
112 params->drive_size))
113 return CGPT_FAILED;
114
115 if (GptCreate(&drive, params))
116 goto bad;
117
118 // Write it all out
119 return DriveClose(&drive, 1);
120
121 bad:
122
123 DriveClose(&drive, 0);
124 return CGPT_FAILED;
125 }
126