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) 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.
*/
#define LOG_TAG "cmd"
#include <utils/Log.h>
#include <binder/Parcel.h>
#include <binder/ProcessState.h>
#include <binder/IResultReceiver.h>
#include <binder/IServiceManager.h>
#include <binder/IShellCallback.h>
#include <binder/TextOutput.h>
#include <utils/Condition.h>
#include <utils/Mutex.h>
#include <utils/Vector.h>
#include <getopt.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/time.h>
#include <errno.h>
#include <memory>
#include "selinux/selinux.h"
#include "selinux/android.h"
#define DEBUG 0
using namespace android;
static int sort_func(const String16* lhs, const String16* rhs)
{
return lhs->compare(*rhs);
}
struct SecurityContext_Delete {
void operator()(security_context_t p) const {
freecon(p);
}
};
typedef std::unique_ptr<char[], SecurityContext_Delete> Unique_SecurityContext;
class MyShellCallback : public BnShellCallback
{
public:
bool mActive = true;
virtual int openOutputFile(const String16& path, const String16& seLinuxContext) {
String8 path8(path);
char cwd[256];
getcwd(cwd, 256);
String8 fullPath(cwd);
fullPath.appendPath(path8);
if (!mActive) {
aerr << "Open attempt after active for: " << fullPath << endl;
return -EPERM;
}
int fd = open(fullPath.string(), O_WRONLY|O_CREAT|O_TRUNC, S_IRWXU|S_IRWXG);
if (fd < 0) {
return fd;
}
if (is_selinux_enabled() && seLinuxContext.size() > 0) {
String8 seLinuxContext8(seLinuxContext);
security_context_t tmp = NULL;
int ret = getfilecon(fullPath.string(), &tmp);
Unique_SecurityContext context(tmp);
int accessGranted = selinux_check_access(seLinuxContext8.string(), context.get(),
"file", "write", NULL);
if (accessGranted != 0) {
close(fd);
aerr << "System server has no access to file context " << context.get()
<< " (from path " << fullPath.string() << ", context "
<< seLinuxContext8.string() << ")" << endl;
return -EPERM;
}
}
return fd;
}
};
class MyResultReceiver : public BnResultReceiver
{
public:
Mutex mMutex;
Condition mCondition;
bool mHaveResult = false;
int32_t mResult = 0;
virtual void send(int32_t resultCode) {
AutoMutex _l(mMutex);
mResult = resultCode;
mHaveResult = true;
mCondition.signal();
}
int32_t waitForResult() {
AutoMutex _l(mMutex);
while (!mHaveResult) {
mCondition.wait(mMutex);
}
return mResult;
}
};
int main(int argc, char* const argv[])
{
signal(SIGPIPE, SIG_IGN);
sp<ProcessState> proc = ProcessState::self();
// setThreadPoolMaxThreadCount(0) actually tells the kernel it's
// not allowed to spawn any additional threads, but we still spawn
// a binder thread from userspace when we call startThreadPool().
// This is safe because we only have 2 callbacks, neither of which
// block.
// See b/36066697 for rationale
proc->setThreadPoolMaxThreadCount(0);
proc->startThreadPool();
sp<IServiceManager> sm = defaultServiceManager();
fflush(stdout);
if (sm == NULL) {
ALOGW("Unable to get default service manager!");
aerr << "cmd: Unable to get default service manager!" << endl;
return 20;
}
if (argc == 1) {
aerr << "cmd: No service specified; use -l to list all services" << endl;
return 20;
}
if ((argc == 2) && (strcmp(argv[1], "-l") == 0)) {
Vector<String16> services = sm->listServices();
services.sort(sort_func);
aout << "Currently running services:" << endl;
for (size_t i=0; i<services.size(); i++) {
sp<IBinder> service = sm->checkService(services[i]);
if (service != NULL) {
aout << " " << services[i] << endl;
}
}
return 0;
}
Vector<String16> args;
for (int i=2; i<argc; i++) {
args.add(String16(argv[i]));
}
String16 cmd = String16(argv[1]);
sp<IBinder> service = sm->checkService(cmd);
if (service == NULL) {
ALOGW("Can't find service %s", argv[1]);
aerr << "cmd: Can't find service: " << argv[1] << endl;
return 20;
}
sp<MyShellCallback> cb = new MyShellCallback();
sp<MyResultReceiver> result = new MyResultReceiver();
#if DEBUG
ALOGD("cmd: Invoking %s in=%d, out=%d, err=%d", argv[1], STDIN_FILENO, STDOUT_FILENO,
STDERR_FILENO);
#endif
// TODO: block until a result is returned to MyResultReceiver.
status_t err = IBinder::shellCommand(service, STDIN_FILENO, STDOUT_FILENO, STDERR_FILENO, args,
cb, result);
if (err < 0) {
const char* errstr;
switch (err) {
case BAD_TYPE: errstr = "Bad type"; break;
case FAILED_TRANSACTION: errstr = "Failed transaction"; break;
case FDS_NOT_ALLOWED: errstr = "File descriptors not allowed"; break;
case UNEXPECTED_NULL: errstr = "Unexpected null"; break;
default: errstr = strerror(-err); break;
}
ALOGW("Failure calling service %s: %s (%d)", argv[1], errstr, -err);
aout << "cmd: Failure calling service " << argv[1] << ": " << errstr << " ("
<< (-err) << ")" << endl;
return err;
}
cb->mActive = false;
status_t res = result->waitForResult();
#if DEBUG
ALOGD("result=%d", (int)res);
#endif
return res;
}
|
