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 #include "sysincludes.h"
7
8 #include "cgptlib.h"
9 #include "cgptlib_internal.h"
10 #include "crc32.h"
11 #include "gpt.h"
12 #include "utility.h"
13 #include "vboot_api.h"
14
GptInit(GptData * gpt)15 int GptInit(GptData *gpt)
16 {
17 int retval;
18
19 gpt->modified = 0;
20 gpt->current_kernel = CGPT_KERNEL_ENTRY_NOT_FOUND;
21 gpt->current_priority = 999;
22
23 retval = GptSanityCheck(gpt);
24 if (GPT_SUCCESS != retval) {
25 VBDEBUG(("GptInit() failed sanity check\n"));
26 return retval;
27 }
28
29 GptRepair(gpt);
30 return GPT_SUCCESS;
31 }
32
GptNextKernelEntry(GptData * gpt,uint64_t * start_sector,uint64_t * size)33 int GptNextKernelEntry(GptData *gpt, uint64_t *start_sector, uint64_t *size)
34 {
35 GptHeader *header = (GptHeader *)gpt->primary_header;
36 GptEntry *entries = (GptEntry *)gpt->primary_entries;
37 GptEntry *e;
38 int new_kernel = CGPT_KERNEL_ENTRY_NOT_FOUND;
39 int new_prio = 0;
40 uint32_t i;
41
42 /*
43 * If we already found a kernel, continue the scan at the current
44 * kernel's priority, in case there is another kernel with the same
45 * priority.
46 */
47 if (gpt->current_kernel != CGPT_KERNEL_ENTRY_NOT_FOUND) {
48 for (i = gpt->current_kernel + 1;
49 i < header->number_of_entries; i++) {
50 e = entries + i;
51 if (!IsKernelEntry(e))
52 continue;
53 VBDEBUG(("GptNextKernelEntry looking at same prio "
54 "partition %d\n", i+1));
55 VBDEBUG(("GptNextKernelEntry s%d t%d p%d\n",
56 GetEntrySuccessful(e), GetEntryTries(e),
57 GetEntryPriority(e)));
58 if (!(GetEntrySuccessful(e) || GetEntryTries(e)))
59 continue;
60 if (GetEntryPriority(e) == gpt->current_priority) {
61 gpt->current_kernel = i;
62 *start_sector = e->starting_lba;
63 *size = e->ending_lba - e->starting_lba + 1;
64 VBDEBUG(("GptNextKernelEntry likes it\n"));
65 return GPT_SUCCESS;
66 }
67 }
68 }
69
70 /*
71 * We're still here, so scan for the remaining kernel with the highest
72 * priority less than the previous attempt.
73 */
74 for (i = 0, e = entries; i < header->number_of_entries; i++, e++) {
75 int current_prio = GetEntryPriority(e);
76 if (!IsKernelEntry(e))
77 continue;
78 VBDEBUG(("GptNextKernelEntry looking at new prio "
79 "partition %d\n", i+1));
80 VBDEBUG(("GptNextKernelEntry s%d t%d p%d\n",
81 GetEntrySuccessful(e), GetEntryTries(e),
82 GetEntryPriority(e)));
83 if (!(GetEntrySuccessful(e) || GetEntryTries(e)))
84 continue;
85 if (current_prio >= gpt->current_priority) {
86 /* Already returned this kernel in a previous call */
87 continue;
88 }
89 if (current_prio > new_prio) {
90 new_kernel = i;
91 new_prio = current_prio;
92 }
93 }
94
95 /*
96 * Save what we found. Note that if we didn't find a new kernel,
97 * new_prio will still be -1, so future calls to this function will
98 * also fail.
99 */
100 gpt->current_kernel = new_kernel;
101 gpt->current_priority = new_prio;
102
103 if (CGPT_KERNEL_ENTRY_NOT_FOUND == new_kernel) {
104 VBDEBUG(("GptNextKernelEntry no more kernels\n"));
105 return GPT_ERROR_NO_VALID_KERNEL;
106 }
107
108 VBDEBUG(("GptNextKernelEntry likes partition %d\n", new_kernel + 1));
109 e = entries + new_kernel;
110 *start_sector = e->starting_lba;
111 *size = e->ending_lba - e->starting_lba + 1;
112 return GPT_SUCCESS;
113 }
114
115 /*
116 * Func: GptUpdateKernelWithEntry
117 * Desc: This function updates the given kernel entry according to the provided
118 * update_type.
119 */
GptUpdateKernelWithEntry(GptData * gpt,GptEntry * e,uint32_t update_type)120 int GptUpdateKernelWithEntry(GptData *gpt, GptEntry *e, uint32_t update_type)
121 {
122 int modified = 0;
123
124 if (!IsKernelEntry(e))
125 return GPT_ERROR_INVALID_UPDATE_TYPE;
126
127 switch (update_type) {
128 case GPT_UPDATE_ENTRY_TRY: {
129 /* Used up a try */
130 int tries;
131 if (GetEntrySuccessful(e)) {
132 /*
133 * Successfully booted this partition, so tries field
134 * is ignored.
135 */
136 return GPT_SUCCESS;
137 }
138 tries = GetEntryTries(e);
139 if (tries > 1) {
140 /* Still have tries left */
141 modified = 1;
142 SetEntryTries(e, tries - 1);
143 break;
144 }
145 /* Out of tries, so drop through and mark partition bad. */
146 }
147 case GPT_UPDATE_ENTRY_BAD: {
148 /* Giving up on this partition entirely. */
149 if (!GetEntrySuccessful(e)) {
150 /*
151 * Only clear tries and priority if the successful bit
152 * is not set.
153 */
154 modified = 1;
155 SetEntryTries(e, 0);
156 SetEntryPriority(e, 0);
157 }
158 break;
159 }
160 case GPT_UPDATE_ENTRY_RESET: {
161 /*
162 * Used for fastboot mode. If image is written to kernel
163 * partition, its GPT entry is marked with S1,P1,T15
164 */
165 modified = 1;
166 SetEntryTries(e, 15);
167 SetEntryPriority(e, 1);
168 SetEntrySuccessful(e, 1);
169 break;
170 }
171 case GPT_UPDATE_ENTRY_INVALID: {
172 /*
173 * Used for fastboot mode. If kernel partition is erased, its
174 * GPT entry is marked with S0,P0,T0
175 */
176 modified = 1;
177 SetEntryTries(e, 0);
178 SetEntryPriority(e, 0);
179 SetEntrySuccessful(e, 0);
180 break;
181 }
182 default:
183 return GPT_ERROR_INVALID_UPDATE_TYPE;
184 }
185
186 if (modified) {
187 GptModified(gpt);
188 }
189
190 return GPT_SUCCESS;
191 }
192
193 /*
194 * Func: GptUpdateKernelEntry
195 * Desc: This function updates current_kernel entry with provided
196 * update_type. If current_kernel is not set, then it returns error.
197 */
GptUpdateKernelEntry(GptData * gpt,uint32_t update_type)198 int GptUpdateKernelEntry(GptData *gpt, uint32_t update_type)
199 {
200 GptEntry *entries = (GptEntry *)gpt->primary_entries;
201 GptEntry *e = entries + gpt->current_kernel;
202
203 if (gpt->current_kernel == CGPT_KERNEL_ENTRY_NOT_FOUND)
204 return GPT_ERROR_INVALID_UPDATE_TYPE;
205
206 return GptUpdateKernelWithEntry(gpt, e, update_type);
207 }
208
209 /*
210 * Func: GptFindNthEntry
211 * Desc: This function returns the nth instance of parition entry matching the
212 * partition type guid from the gpt table. Instance value starts from 0. If the
213 * entry is not found it returns NULL.
214 */
GptFindNthEntry(GptData * gpt,const Guid * guid,unsigned int n)215 GptEntry *GptFindNthEntry(GptData *gpt, const Guid *guid, unsigned int n)
216 {
217 GptHeader *header = (GptHeader *)gpt->primary_header;
218 GptEntry *entries = (GptEntry *)gpt->primary_entries;
219 GptEntry *e;
220 int i;
221
222 for (i = 0, e = entries; i < header->number_of_entries; i++, e++) {
223 if (!Memcmp(&e->type, guid, sizeof(*guid))) {
224 if (n == 0)
225 return e;
226 n--;
227 }
228 }
229
230 return NULL;
231 }
232