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
|
/*
* Copyright (C) 2019 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.
*/
#define LOG_TAG "Stability"
#include <binder/Stability.h>
#include <binder/BpBinder.h>
#include <binder/Binder.h>
namespace android {
namespace internal {
// the libbinder parcel format is currently unstable
// oldest version which is supported
constexpr uint8_t kBinderWireFormatOldest = 1;
// current version
constexpr uint8_t kBinderWireFormatVersion = 1;
Stability::Category Stability::Category::currentFromLevel(Level level) {
return {
.version = kBinderWireFormatVersion,
.reserved = {0},
.level = level,
};
}
void Stability::forceDowngradeToStability(const sp<IBinder>& binder, Level level) {
// Downgrading a remote binder would require also copying the version from
// the binder sent here. In practice though, we don't need to downgrade the
// stability of a remote binder, since this would as an effect only restrict
// what we can do to it.
LOG_ALWAYS_FATAL_IF(!binder || !binder->localBinder(), "Can only downgrade local binder");
auto stability = Category::currentFromLevel(level);
status_t result = setRepr(binder.get(), stability.repr(), REPR_LOG | REPR_ALLOW_DOWNGRADE);
LOG_ALWAYS_FATAL_IF(result != OK, "Should only mark known object.");
}
void Stability::forceDowngradeToLocalStability(const sp<IBinder>& binder) {
forceDowngradeToStability(binder, getLocalLevel());
}
void Stability::forceDowngradeToSystemStability(const sp<IBinder>& binder) {
forceDowngradeToStability(binder, Level::SYSTEM);
}
void Stability::forceDowngradeToVendorStability(const sp<IBinder>& binder) {
forceDowngradeToStability(binder, Level::VENDOR);
}
std::string Stability::Category::debugString() {
return levelString(level) + " wire protocol version "
+ std::to_string(version);
}
void Stability::markCompilationUnit(IBinder* binder) {
auto stability = Category::currentFromLevel(getLocalLevel());
status_t result = setRepr(binder, stability.repr(), REPR_LOG);
LOG_ALWAYS_FATAL_IF(result != OK, "Should only mark known object.");
}
void Stability::markVintf(IBinder* binder) {
auto stability = Category::currentFromLevel(Level::VINTF);
status_t result = setRepr(binder, stability.repr(), REPR_LOG);
LOG_ALWAYS_FATAL_IF(result != OK, "Should only mark known object.");
}
void Stability::debugLogStability(const std::string& tag, const sp<IBinder>& binder) {
auto stability = getCategory(binder.get());
ALOGE("%s: stability is %s", tag.c_str(), stability.debugString().c_str());
}
void Stability::markVndk(IBinder* binder) {
auto stability = Category::currentFromLevel(Level::VENDOR);
status_t result = setRepr(binder, stability.repr(), REPR_LOG);
LOG_ALWAYS_FATAL_IF(result != OK, "Should only mark known object.");
}
bool Stability::requiresVintfDeclaration(const sp<IBinder>& binder) {
return check(getCategory(binder.get()), Level::VINTF);
}
void Stability::tryMarkCompilationUnit(IBinder* binder) {
auto stability = Category::currentFromLevel(getLocalLevel());
(void) setRepr(binder, stability.repr(), REPR_NONE);
}
Stability::Level Stability::getLocalLevel() {
#ifdef __ANDROID_APEX__
#error APEX can't use libbinder (must use libbinder_ndk)
#endif
#ifdef __ANDROID_VNDK__
return Level::VENDOR;
#else
// TODO(b/139325195): split up stability levels for system/APEX.
return Level::SYSTEM;
#endif
}
status_t Stability::setRepr(IBinder* binder, int32_t representation, uint32_t flags) {
bool log = flags & REPR_LOG;
bool allowDowngrade = flags & REPR_ALLOW_DOWNGRADE;
auto current = getCategory(binder);
auto setting = Category::fromRepr(representation);
// If we have ahold of a binder with a newer declared version, then it
// should support older versions, and we will simply write our parcels with
// the current wire parcel format.
if (setting.version < kBinderWireFormatOldest) {
// always log, because this shouldn't happen
ALOGE("Cannot accept binder with older binder wire protocol version "
"%u. Versions less than %u are unsupported.", setting.version,
kBinderWireFormatOldest);
return BAD_TYPE;
}
// null binder is always written w/ 'UNDECLARED' stability
if (binder == nullptr) {
if (setting.level == UNDECLARED) {
return OK;
} else {
if (log) {
ALOGE("Null binder written with stability %s.",
levelString(setting.level).c_str());
}
return BAD_TYPE;
}
}
if (!isDeclaredLevel(setting.level)) {
if (log) {
ALOGE("Can only set known stability, not %u.", setting.level);
}
return BAD_TYPE;
}
if (current == setting) return OK;
bool hasAlreadyBeenSet = current.repr() != 0;
bool isAllowedDowngrade = allowDowngrade && check(current, setting.level);
if (hasAlreadyBeenSet && !isAllowedDowngrade) {
if (log) {
ALOGE("Interface being set with %s but it is already marked as %s",
setting.debugString().c_str(),
current.debugString().c_str());
}
return BAD_TYPE;
}
if (isAllowedDowngrade) {
ALOGI("Interface set with %s downgraded to %s stability",
current.debugString().c_str(),
setting.debugString().c_str());
}
BBinder* local = binder->localBinder();
if (local != nullptr) {
local->mStability = setting.repr();
} else {
binder->remoteBinder()->mStability = setting.repr();
}
return OK;
}
Stability::Category Stability::getCategory(IBinder* binder) {
if (binder == nullptr) {
return Category::currentFromLevel(Level::UNDECLARED);
}
BBinder* local = binder->localBinder();
if (local != nullptr) {
return Category::fromRepr(local->mStability);
}
return Category::fromRepr(binder->remoteBinder()->mStability);
}
bool Stability::check(Category provided, Level required) {
bool stable = (provided.level & required) == required;
if (provided.level != UNDECLARED && !isDeclaredLevel(provided.level)) {
ALOGE("Unknown stability when checking interface stability %d.",
provided.level);
stable = false;
}
return stable;
}
bool Stability::isDeclaredLevel(Level stability) {
return stability == VENDOR || stability == SYSTEM || stability == VINTF;
}
std::string Stability::levelString(Level level) {
switch (level) {
case Level::UNDECLARED: return "undeclared stability";
case Level::VENDOR: return "vendor stability";
case Level::SYSTEM: return "system stability";
case Level::VINTF: return "vintf stability";
}
return "unknown stability " + std::to_string(level);
}
} // namespace internal
} // namespace stability
|
