1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
|
// SPDX-License-Identifier: GPL-2.0+
/*
* EFI boot manager
*
* Copyright (c) 2017 Rob Clark
*/
#define LOG_CATEGORY LOGC_EFI
#include <common.h>
#include <charset.h>
#include <log.h>
#include <malloc.h>
#include <efi_loader.h>
#include <efi_variable.h>
#include <asm/unaligned.h>
static const struct efi_boot_services *bs;
static const struct efi_runtime_services *rs;
/*
* bootmgr implements the logic of trying to find a payload to boot
* based on the BootOrder + BootXXXX variables, and then loading it.
*
* TODO detecting a special key held (f9?) and displaying a boot menu
* like you would get on a PC would be clever.
*
* TODO if we had a way to write and persist variables after the OS
* has started, we'd also want to check OsIndications to see if we
* should do normal or recovery boot.
*/
/**
* efi_deserialize_load_option() - parse serialized data
*
* Parse serialized data describing a load option and transform it to the
* efi_load_option structure.
*
* @lo: pointer to target
* @data: serialized data
* @size: size of the load option, on return size of the optional data
* Return: status code
*/
efi_status_t efi_deserialize_load_option(struct efi_load_option *lo, u8 *data,
efi_uintn_t *size)
{
efi_uintn_t len;
len = sizeof(u32);
if (*size < len + 2 * sizeof(u16))
return EFI_INVALID_PARAMETER;
lo->attributes = get_unaligned_le32(data);
data += len;
*size -= len;
len = sizeof(u16);
lo->file_path_length = get_unaligned_le16(data);
data += len;
*size -= len;
lo->label = (u16 *)data;
len = u16_strnlen(lo->label, *size / sizeof(u16) - 1);
if (lo->label[len])
return EFI_INVALID_PARAMETER;
len = (len + 1) * sizeof(u16);
if (*size < len)
return EFI_INVALID_PARAMETER;
data += len;
*size -= len;
len = lo->file_path_length;
if (*size < len)
return EFI_INVALID_PARAMETER;
lo->file_path = (struct efi_device_path *)data;
/*
* TODO: validate device path. There should be an end node within
* the indicated file_path_length.
*/
data += len;
*size -= len;
lo->optional_data = data;
return EFI_SUCCESS;
}
/**
* efi_serialize_load_option() - serialize load option
*
* Serialize efi_load_option structure into byte stream for BootXXXX.
*
* @data: buffer for serialized data
* @lo: load option
* Return: size of allocated buffer
*/
unsigned long efi_serialize_load_option(struct efi_load_option *lo, u8 **data)
{
unsigned long label_len;
unsigned long size;
u8 *p;
label_len = (u16_strlen(lo->label) + 1) * sizeof(u16);
/* total size */
size = sizeof(lo->attributes);
size += sizeof(lo->file_path_length);
size += label_len;
size += lo->file_path_length;
if (lo->optional_data)
size += (utf8_utf16_strlen((const char *)lo->optional_data)
+ 1) * sizeof(u16);
p = malloc(size);
if (!p)
return 0;
/* copy data */
*data = p;
memcpy(p, &lo->attributes, sizeof(lo->attributes));
p += sizeof(lo->attributes);
memcpy(p, &lo->file_path_length, sizeof(lo->file_path_length));
p += sizeof(lo->file_path_length);
memcpy(p, lo->label, label_len);
p += label_len;
memcpy(p, lo->file_path, lo->file_path_length);
p += lo->file_path_length;
if (lo->optional_data) {
utf8_utf16_strcpy((u16 **)&p, (const char *)lo->optional_data);
p += sizeof(u16); /* size of trailing \0 */
}
return size;
}
/**
* get_var() - get UEFI variable
*
* It is the caller's duty to free the returned buffer.
*
* @name: name of variable
* @vendor: vendor GUID of variable
* @size: size of allocated buffer
* Return: buffer with variable data or NULL
*/
static void *get_var(u16 *name, const efi_guid_t *vendor,
efi_uintn_t *size)
{
efi_status_t ret;
void *buf = NULL;
*size = 0;
ret = efi_get_variable_int(name, vendor, NULL, size, buf, NULL);
if (ret == EFI_BUFFER_TOO_SMALL) {
buf = malloc(*size);
ret = efi_get_variable_int(name, vendor, NULL, size, buf, NULL);
}
if (ret != EFI_SUCCESS) {
free(buf);
*size = 0;
return NULL;
}
return buf;
}
/**
* try_load_entry() - try to load image for boot option
*
* Attempt to load load-option number 'n', returning device_path and file_path
* if successful. This checks that the EFI_LOAD_OPTION is active (enabled)
* and that the specified file to boot exists.
*
* @n: number of the boot option, e.g. 0x0a13 for Boot0A13
* @handle: on return handle for the newly installed image
* Return: status code
*/
static efi_status_t try_load_entry(u16 n, efi_handle_t *handle)
{
struct efi_load_option lo;
u16 varname[] = L"Boot0000";
u16 hexmap[] = L"0123456789ABCDEF";
void *load_option;
efi_uintn_t size;
efi_status_t ret;
varname[4] = hexmap[(n & 0xf000) >> 12];
varname[5] = hexmap[(n & 0x0f00) >> 8];
varname[6] = hexmap[(n & 0x00f0) >> 4];
varname[7] = hexmap[(n & 0x000f) >> 0];
load_option = get_var(varname, &efi_global_variable_guid, &size);
if (!load_option)
return EFI_LOAD_ERROR;
ret = efi_deserialize_load_option(&lo, load_option, &size);
if (ret != EFI_SUCCESS) {
log_warning("Invalid load option for %ls\n", varname);
goto error;
}
if (lo.attributes & LOAD_OPTION_ACTIVE) {
u32 attributes;
log_debug("%s: trying to load \"%ls\" from %pD\n",
__func__, lo.label, lo.file_path);
ret = EFI_CALL(efi_load_image(true, efi_root, lo.file_path,
NULL, 0, handle));
if (ret != EFI_SUCCESS) {
log_warning("Loading %ls '%ls' failed\n",
varname, lo.label);
goto error;
}
attributes = EFI_VARIABLE_BOOTSERVICE_ACCESS |
EFI_VARIABLE_RUNTIME_ACCESS;
size = sizeof(n);
ret = efi_set_variable_int(L"BootCurrent",
&efi_global_variable_guid,
attributes, size, &n, false);
if (ret != EFI_SUCCESS) {
if (EFI_CALL(efi_unload_image(*handle))
!= EFI_SUCCESS)
log_err("Unloading image failed\n");
goto error;
}
log_info("Booting: %ls\n", lo.label);
} else {
ret = EFI_LOAD_ERROR;
}
error:
free(load_option);
return ret;
}
/**
* efi_bootmgr_load() - try to load from BootNext or BootOrder
*
* Attempt to load from BootNext or in the order specified by BootOrder
* EFI variable, the available load-options, finding and returning
* the first one that can be loaded successfully.
*
* @handle: on return handle for the newly installed image
* Return: status code
*/
efi_status_t efi_bootmgr_load(efi_handle_t *handle)
{
u16 bootnext, *bootorder;
efi_uintn_t size;
int i, num;
efi_status_t ret;
bs = systab.boottime;
rs = systab.runtime;
/* BootNext */
size = sizeof(bootnext);
ret = efi_get_variable_int(L"BootNext",
&efi_global_variable_guid,
NULL, &size, &bootnext, NULL);
if (ret == EFI_SUCCESS || ret == EFI_BUFFER_TOO_SMALL) {
/* BootNext does exist here */
if (ret == EFI_BUFFER_TOO_SMALL || size != sizeof(u16))
log_err("BootNext must be 16-bit integer\n");
/* delete BootNext */
ret = efi_set_variable_int(L"BootNext",
&efi_global_variable_guid,
0, 0, NULL, false);
/* load BootNext */
if (ret == EFI_SUCCESS) {
if (size == sizeof(u16)) {
ret = try_load_entry(bootnext, handle);
if (ret == EFI_SUCCESS)
return ret;
log_warning(
"Loading from BootNext failed, falling back to BootOrder\n");
}
} else {
log_err("Deleting BootNext failed\n");
}
}
/* BootOrder */
bootorder = get_var(L"BootOrder", &efi_global_variable_guid, &size);
if (!bootorder) {
log_info("BootOrder not defined\n");
ret = EFI_NOT_FOUND;
goto error;
}
num = size / sizeof(uint16_t);
for (i = 0; i < num; i++) {
log_debug("%s trying to load Boot%04X\n", __func__,
bootorder[i]);
ret = try_load_entry(bootorder[i], handle);
if (ret == EFI_SUCCESS)
break;
}
free(bootorder);
error:
return ret;
}
|