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1 /* Copyright (c) 2013 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 #ifndef VBOOT_REFERENCE_CGPTLIB_INTERNAL_H_
7 #define VBOOT_REFERENCE_CGPTLIB_INTERNAL_H_
8 
9 #include "sysincludes.h"
10 #include "cgptlib.h"
11 #include "gpt.h"
12 
13 /*
14  * If gpt->current_kernel is this value, means either:
15  *   1. an initial value before scanning GPT entries,
16  *   2. after scanning, no any valid kernel is found.
17  */
18 #define CGPT_KERNEL_ENTRY_NOT_FOUND (-1)
19 
20 /*
21  * Bit definitions and masks for GPT attributes.
22  *
23  *  63-61  -- (reserved)
24  *     60  -- read-only
25  *  59-57  -- (reserved)
26  *     56  -- success
27  *  55-52  -- tries
28  *  51-48  -- priority
29  *   47-2  -- UEFI: reserved for future use
30  *      1  -- UEFI: partition is not mapped
31  *      0  -- UEFI: partition is required
32  */
33 #define CGPT_ATTRIBUTE_SUCCESSFUL_OFFSET (56 - 48)
34 #define CGPT_ATTRIBUTE_MAX_SUCCESSFUL (1ULL)
35 #define CGPT_ATTRIBUTE_SUCCESSFUL_MASK (CGPT_ATTRIBUTE_MAX_SUCCESSFUL << \
36                                      CGPT_ATTRIBUTE_SUCCESSFUL_OFFSET)
37 
38 #define CGPT_ATTRIBUTE_TRIES_OFFSET (52 - 48)
39 #define CGPT_ATTRIBUTE_MAX_TRIES (15ULL)
40 #define CGPT_ATTRIBUTE_TRIES_MASK (CGPT_ATTRIBUTE_MAX_TRIES << \
41                                    CGPT_ATTRIBUTE_TRIES_OFFSET)
42 
43 #define CGPT_ATTRIBUTE_PRIORITY_OFFSET (48 - 48)
44 #define CGPT_ATTRIBUTE_MAX_PRIORITY (15ULL)
45 #define CGPT_ATTRIBUTE_PRIORITY_MASK (CGPT_ATTRIBUTE_MAX_PRIORITY << \
46                                       CGPT_ATTRIBUTE_PRIORITY_OFFSET)
47 
48 /* Defines ChromeOS-specific limitation on GPT */
49 #define MIN_SIZE_OF_HEADER 92
50 #define MAX_SIZE_OF_HEADER 512
51 #define MIN_SIZE_OF_ENTRY 128
52 #define MAX_SIZE_OF_ENTRY 512
53 #define SIZE_OF_ENTRY_MULTIPLE 8
54 #define MIN_NUMBER_OF_ENTRIES 16
55 #define MAX_NUMBER_OF_ENTRIES 128
56 
57 /* Defines GPT sizes */
58 #define GPT_PMBR_SECTORS 1  /* size (in sectors) of PMBR */
59 #define GPT_HEADER_SECTORS 1
60 
61 /*
62  * Alias name of index in internal array for primary and secondary header and
63  * entries.
64  */
65 enum {
66 	/* constants for index */
67 	PRIMARY = 0,
68 	SECONDARY = 1,
69 	ANY_VALID = 9999,  /* accept any between primary and secondary */
70 
71 	/* constants for bit mask */
72 	MASK_NONE = 0,
73 	MASK_PRIMARY = 1,
74 	MASK_SECONDARY = 2,
75 	MASK_BOTH = 3,
76 };
77 
78 /**
79  * Verify GptData parameters are sane.
80  */
81 int CheckParameters(GptData* gpt);
82 
83 /**
84  * Check header fields.
85  *
86  * Returns 0 if header is valid, 1 if invalid.
87  */
88 int CheckHeader(GptHeader *h, int is_secondary,
89                 uint64_t streaming_drive_sectors,
90                 uint64_t gpt_drive_sectors, uint32_t flags);
91 
92 /**
93  * Calculate and return the header CRC.
94  */
95 uint32_t HeaderCrc(GptHeader *h);
96 
97 /**
98  * Check entries.
99  *
100  * Returns 0 if entries are valid, 1 if invalid.
101  */
102 int CheckEntries(GptEntry *entries, GptHeader *h);
103 
104 /**
105  * Return 0 if the GptHeaders are the same for all fields which don't differ
106  * between the primary and secondary headers - that is, all fields other than:
107  *
108  * my_lba
109  * alternate_lba
110  * entries_lba
111  */
112 int HeaderFieldsSame(GptHeader *h1, GptHeader *h2);
113 
114 /**
115  * Check GptData, headers, entries.
116  *
117  * If successful, sets gpt->valid_headers and gpt->valid_entries and returns
118  * GPT_SUCCESS.
119  *
120  * On error, returns a GPT_ERROR_* return code.
121  */
122 int GptSanityCheck(GptData *gpt);
123 
124 /**
125  * Repair GPT data by copying from one set of valid headers/entries to the
126  * other.  Assumes GptSanityCheck() has been run to determine which headers
127  * and/or entries are already valid.
128  */
129 void GptRepair(GptData *gpt);
130 
131 /**
132  * Called when the primary entries are modified and the CRCs need to be
133  * recalculated and propagated to the secondary entries
134  */
135 void GptModified(GptData *gpt);
136 
137 /* Getters and setters for partition attribute fields. */
138 
139 int GetEntrySuccessful(const GptEntry *e);
140 int GetEntryPriority(const GptEntry *e);
141 int GetEntryTries(const GptEntry *e);
142 void SetEntrySuccessful(GptEntry *e, int successful);
143 void SetEntryPriority(GptEntry *e, int priority);
144 void SetEntryTries(GptEntry *e, int tries);
145 
146 /**
147  * Return 1 if the entry is a Chrome OS kernel partition, else 0.
148  */
149 int IsKernelEntry(const GptEntry *e);
150 
151 /**
152  * Copy the current kernel partition's UniquePartitionGuid to the dest.
153  */
154 void GetCurrentKernelUniqueGuid(GptData *gpt, void *dest);
155 
156 /**
157  * Return a pointer to text describing the passed in error.
158  */
159 const char *GptErrorText(int error_code);
160 
161 /**
162  * Return number of 512-byte sectors required to store the entries table.
163  */
164 size_t CalculateEntriesSectors(GptHeader* h);
165 
166 #endif /* VBOOT_REFERENCE_CGPTLIB_INTERNAL_H_ */
167