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
|
/*
* Copyright (C) 2017 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 <algorithm>
#include <iterator>
#include <string>
#include <android-base/file.h>
#include <android-base/properties.h>
#include <android-base/strings.h>
#include "fstab_priv.h"
#include "logging_macros.h"
namespace android {
namespace fs_mgr {
const std::string& GetAndroidDtDir() {
// Set once and saves time for subsequent calls to this function
static const std::string kAndroidDtDir = [] {
std::string android_dt_dir;
if ((GetBootconfig("androidboot.android_dt_dir", &android_dt_dir) ||
GetKernelCmdline("androidboot.android_dt_dir", &android_dt_dir)) &&
!android_dt_dir.empty()) {
// Ensure the returned path ends with a /
if (android_dt_dir.back() != '/') {
android_dt_dir.push_back('/');
}
} else {
// Fall back to the standard procfs-based path
android_dt_dir = "/proc/device-tree/firmware/android/";
}
LINFO << "Using Android DT directory " << android_dt_dir;
return android_dt_dir;
}();
return kAndroidDtDir;
}
void ImportBootconfigFromString(const std::string& bootconfig,
const std::function<void(std::string, std::string)>& fn) {
for (std::string_view line : android::base::Split(bootconfig, "\n")) {
const auto equal_pos = line.find('=');
std::string key = android::base::Trim(line.substr(0, equal_pos));
if (key.empty()) {
continue;
}
std::string value;
if (equal_pos != line.npos) {
value = android::base::Trim(line.substr(equal_pos + 1));
// If the value is a comma-delimited list, the kernel would insert a space between the
// list elements when read from /proc/bootconfig.
// BoardConfig.mk:
// BOARD_BOOTCONFIG := key=value1,value2,value3
// /proc/bootconfig:
// key = "value1", "value2", "value3"
if (key == "androidboot.boot_device" || key == "androidboot.boot_devices") {
// boot_device[s] is a special case where a list element can contain comma and the
// caller expects a space-delimited list, so don't remove space here.
value.erase(std::remove(value.begin(), value.end(), '"'), value.end());
} else {
// In order to not break the expectations of existing code, we modify the value to
// keep the format consistent with the kernel cmdline by removing quote and space.
std::string_view sv(value);
android::base::ConsumePrefix(&sv, "\"");
android::base::ConsumeSuffix(&sv, "\"");
value = android::base::StringReplace(sv, R"(", ")", ",", true);
}
}
// "key" and "key =" means empty value.
fn(std::move(key), std::move(value));
}
}
bool GetBootconfigFromString(const std::string& bootconfig, const std::string& key,
std::string* out) {
bool found = false;
ImportBootconfigFromString(bootconfig, [&](std::string config_key, std::string value) {
if (!found && config_key == key) {
*out = std::move(value);
found = true;
}
});
return found;
}
void ImportBootconfig(const std::function<void(std::string, std::string)>& fn) {
std::string bootconfig;
android::base::ReadFileToString("/proc/bootconfig", &bootconfig);
ImportBootconfigFromString(bootconfig, fn);
}
bool GetBootconfig(const std::string& key, std::string* out) {
std::string bootconfig;
android::base::ReadFileToString("/proc/bootconfig", &bootconfig);
return GetBootconfigFromString(bootconfig, key, out);
}
void ImportKernelCmdlineFromString(const std::string& cmdline,
const std::function<void(std::string, std::string)>& fn) {
static constexpr char quote = '"';
size_t base = 0;
while (true) {
// skip quoted spans
auto found = base;
while (((found = cmdline.find_first_of(" \"", found)) != cmdline.npos) &&
(cmdline[found] == quote)) {
// unbalanced quote is ok
if ((found = cmdline.find(quote, found + 1)) == cmdline.npos) break;
++found;
}
std::string piece = cmdline.substr(base, found - base);
piece.erase(std::remove(piece.begin(), piece.end(), quote), piece.end());
auto equal_sign = piece.find('=');
if (equal_sign == piece.npos) {
if (!piece.empty()) {
// no difference between <key> and <key>=
fn(std::move(piece), "");
}
} else {
std::string value = piece.substr(equal_sign + 1);
piece.resize(equal_sign);
fn(std::move(piece), std::move(value));
}
if (found == cmdline.npos) break;
base = found + 1;
}
}
bool GetKernelCmdlineFromString(const std::string& cmdline, const std::string& key,
std::string* out) {
bool found = false;
ImportKernelCmdlineFromString(cmdline, [&](std::string config_key, std::string value) {
if (!found && config_key == key) {
*out = std::move(value);
found = true;
}
});
return found;
}
void ImportKernelCmdline(const std::function<void(std::string, std::string)>& fn) {
std::string cmdline;
android::base::ReadFileToString("/proc/cmdline", &cmdline);
ImportKernelCmdlineFromString(android::base::Trim(cmdline), fn);
}
bool GetKernelCmdline(const std::string& key, std::string* out) {
std::string cmdline;
android::base::ReadFileToString("/proc/cmdline", &cmdline);
return GetKernelCmdlineFromString(android::base::Trim(cmdline), key, out);
}
} // namespace fs_mgr
} // namespace android
// Tries to get the boot config value in device tree, properties, kernel bootconfig and kernel
// cmdline (in that order).
// Returns 'true' if successfully found, 'false' otherwise.
bool fs_mgr_get_boot_config(const std::string& key, std::string* out_val) {
FSTAB_CHECK(out_val != nullptr);
// firstly, check the device tree
if (is_dt_compatible()) {
std::string file_name = android::fs_mgr::GetAndroidDtDir() + key;
if (android::base::ReadFileToString(file_name, out_val)) {
if (!out_val->empty()) {
out_val->pop_back(); // Trims the trailing '\0' out.
return true;
}
}
}
// next, check if we have "ro.boot" property already
*out_val = android::base::GetProperty("ro.boot." + key, "");
if (!out_val->empty()) {
return true;
}
// next, check if we have the property in bootconfig
const std::string config_key = "androidboot." + key;
if (android::fs_mgr::GetBootconfig(config_key, out_val)) {
return true;
}
// finally, fallback to kernel cmdline, properties may not be ready yet
if (android::fs_mgr::GetKernelCmdline(config_key, out_val)) {
return true;
}
return false;
}
|
