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
|
/*
* Copyright (C) 2015 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <ctype.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <cutils/properties.h>
#include "fs_mgr.h"
#include "fs_mgr_priv.h"
#include "bootloader.h"
// Copies slot_suffix from misc into |out_suffix|. Returns 0 on
// success, -1 on error or if there is no non-empty slot_suffix.
static int get_active_slot_suffix_from_misc(struct fstab *fstab,
char *out_suffix,
size_t suffix_len)
{
int n;
int misc_fd;
ssize_t num_read;
struct bootloader_message msg;
misc_fd = -1;
for (n = 0; n < fstab->num_entries; n++) {
if (strcmp(fstab->recs[n].mount_point, "/misc") == 0) {
misc_fd = open(fstab->recs[n].blk_device, O_RDONLY);
if (misc_fd == -1) {
ERROR("Error opening misc partition \"%s\" (%s)\n",
fstab->recs[n].blk_device,
strerror(errno));
return -1;
} else {
break;
}
}
}
if (misc_fd == -1) {
ERROR("Error finding misc partition\n");
return -1;
}
num_read = TEMP_FAILURE_RETRY(read(misc_fd, &msg, sizeof(msg)));
// Linux will never return partial reads when reading from block
// devices so no need to worry about them.
if (num_read != sizeof(msg)) {
ERROR("Error reading bootloader_message (%s)\n", strerror(errno));
close(misc_fd);
return -1;
}
close(misc_fd);
if (msg.slot_suffix[0] == '\0')
return -1;
strncpy(out_suffix, msg.slot_suffix, suffix_len);
return 0;
}
// Gets slot_suffix from either the kernel cmdline / firmware or the
// misc partition. Sets |out_suffix| on success and returns 0. Returns
// -1 if slot_suffix could not be determined.
static int get_active_slot_suffix(struct fstab *fstab, char *out_suffix,
size_t suffix_len)
{
char propbuf[PROPERTY_VALUE_MAX];
// Get the suffix from the kernel commandline (note that we don't
// allow the empty suffix). On bootloaders natively supporting A/B
// we'll hit this path every time so don't bother logging it.
property_get("ro.boot.slot_suffix", propbuf, "");
if (propbuf[0] != '\0') {
strncpy(out_suffix, propbuf, suffix_len);
return 0;
}
// If we couldn't get the suffix from the kernel cmdline, try the
// the misc partition.
if (get_active_slot_suffix_from_misc(fstab, out_suffix, suffix_len) == 0) {
INFO("Using slot suffix \"%s\" from misc\n", out_suffix);
return 0;
}
ERROR("Error determining slot_suffix\n");
return -1;
}
// Updates |fstab| for slot_suffix. Returns 0 on success, -1 on error.
int fs_mgr_update_for_slotselect(struct fstab *fstab)
{
int n;
char suffix[PROPERTY_VALUE_MAX];
int got_suffix = 0;
for (n = 0; n < fstab->num_entries; n++) {
if (fstab->recs[n].fs_mgr_flags & MF_SLOTSELECT) {
char *tmp;
if (!got_suffix) {
memset(suffix, '\0', sizeof(suffix));
if (get_active_slot_suffix(fstab, suffix,
sizeof(suffix) - 1) != 0) {
return -1;
}
got_suffix = 1;
}
if (asprintf(&tmp, "%s%s", fstab->recs[n].blk_device,
suffix) > 0) {
free(fstab->recs[n].blk_device);
fstab->recs[n].blk_device = tmp;
} else {
return -1;
}
}
}
return 0;
}
|
