1 #include "VirtualTouchpadService.h"
2
3 #include <inttypes.h>
4
5 #include <binder/IPCThreadState.h>
6 #include <binder/PermissionCache.h>
7 #include <binder/Status.h>
8 #include <cutils/log.h>
9 #include <linux/input.h>
10 #include <private/android_filesystem_config.h>
11 #include <utils/Errors.h>
12
13 namespace android {
14 namespace dvr {
15
16 namespace {
17 const String16 kDumpPermission("android.permission.DUMP");
18 const String16 kTouchPermission("android.permission.RESTRICTED_VR_ACCESS");
19 } // anonymous namespace
20
~VirtualTouchpadService()21 VirtualTouchpadService::~VirtualTouchpadService() {
22 if (client_pid_) {
23 client_pid_ = 0;
24 touchpad_->Detach();
25 }
26 }
27
attach()28 binder::Status VirtualTouchpadService::attach() {
29 pid_t pid;
30 if (!CheckTouchPermission(&pid)) {
31 return binder::Status::fromStatusT(PERMISSION_DENIED);
32 }
33 if (client_pid_ == pid) {
34 // The same client has called attach() twice with no intervening detach().
35 // This indicates a problem with the client, so return an error.
36 // However, since the client is already attached, any touchpad actions
37 // it takes will still work.
38 ALOGE("pid=%ld attached twice", static_cast<long>(pid));
39 return binder::Status::fromStatusT(ALREADY_EXISTS);
40 }
41 if (client_pid_ != 0) {
42 // Attach while another client is attached. This can happen if the client
43 // dies without cleaning up after itself, so move ownership to the current
44 // caller. If two actual clients have connected, the problem will be
45 // reported when the previous client performs any touchpad action.
46 ALOGE("pid=%ld replaces %ld", static_cast<long>(pid),
47 static_cast<long>(client_pid_));
48 client_pid_ = pid;
49 return binder::Status::ok();
50 }
51 client_pid_ = pid;
52 if (const status_t error = touchpad_->Attach()) {
53 return binder::Status::fromStatusT(error);
54 }
55 return binder::Status::ok();
56 }
57
detach()58 binder::Status VirtualTouchpadService::detach() {
59 if (!CheckPermissions()) {
60 return binder::Status::fromStatusT(PERMISSION_DENIED);
61 }
62 client_pid_ = 0;
63 if (const status_t error = touchpad_->Detach()) {
64 return binder::Status::fromStatusT(error);
65 }
66 return binder::Status::ok();
67 }
68
touch(int touchpad,float x,float y,float pressure)69 binder::Status VirtualTouchpadService::touch(int touchpad, float x, float y,
70 float pressure) {
71 if (!CheckPermissions()) {
72 return binder::Status::fromStatusT(PERMISSION_DENIED);
73 }
74 if (const status_t error = touchpad_->Touch(touchpad, x, y, pressure)) {
75 return binder::Status::fromStatusT(error);
76 }
77 return binder::Status::ok();
78 }
79
buttonState(int touchpad,int buttons)80 binder::Status VirtualTouchpadService::buttonState(int touchpad, int buttons) {
81 if (!CheckPermissions()) {
82 return binder::Status::fromStatusT(PERMISSION_DENIED);
83 }
84 if (const status_t error = touchpad_->ButtonState(touchpad, buttons)) {
85 return binder::Status::fromStatusT(error);
86 }
87 return binder::Status::ok();
88 }
89
scroll(int touchpad,float x,float y)90 binder::Status VirtualTouchpadService::scroll(int touchpad, float x, float y) {
91 if (!CheckPermissions()) {
92 return binder::Status::fromStatusT(PERMISSION_DENIED);
93 }
94 if (const status_t error = touchpad_->Scroll(touchpad, x, y)) {
95 return binder::Status::fromStatusT(error);
96 }
97 return binder::Status::ok();
98 }
99
dump(int fd,const Vector<String16> & args)100 status_t VirtualTouchpadService::dump(
101 int fd, const Vector<String16>& args[[gnu::unused]]) {
102 String8 result;
103 const android::IPCThreadState* ipc = android::IPCThreadState::self();
104 const pid_t pid = ipc->getCallingPid();
105 const uid_t uid = ipc->getCallingUid();
106 if ((uid != AID_SHELL) &&
107 !PermissionCache::checkPermission(kDumpPermission, pid, uid)) {
108 result.appendFormat("Permission denial: can't dump " LOG_TAG
109 " from pid=%ld, uid=%ld\n",
110 static_cast<long>(pid), static_cast<long>(uid));
111 } else {
112 result.appendFormat("[service]\nclient_pid = %ld\n\n",
113 static_cast<long>(client_pid_));
114 touchpad_->dumpInternal(result);
115 }
116 write(fd, result.string(), result.size());
117 return OK;
118 }
119
CheckPermissions()120 bool VirtualTouchpadService::CheckPermissions() {
121 pid_t pid;
122 if (!CheckTouchPermission(&pid)) {
123 return false;
124 }
125 if (client_pid_ != pid) {
126 ALOGE("pid=%ld is not owner", static_cast<long>(pid));
127 return false;
128 }
129 return true;
130 }
131
CheckTouchPermission(pid_t * out_pid)132 bool VirtualTouchpadService::CheckTouchPermission(pid_t* out_pid) {
133 const android::IPCThreadState* ipc = android::IPCThreadState::self();
134 *out_pid = ipc->getCallingPid();
135 const uid_t uid = ipc->getCallingUid();
136 const bool permission = PermissionCache::checkPermission(kTouchPermission, *out_pid, uid);
137 if (!permission) {
138 ALOGE("permission denied to pid=%ld uid=%ld", static_cast<long>(*out_pid),
139 static_cast<long>(uid));
140 }
141 return permission;
142 }
143
144 } // namespace dvr
145 } // namespace android
146