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      1 /*
      2  * Copyright (C) 2010 The Android Open Source Project
      3  * Copyright (C) 2012-2014, The Linux Foundation. All rights reserved.
      4  *
      5  * Not a Contribution, Apache license notifications and license are
      6  * retained for attribution purposes only.
      7 
      8  * Licensed under the Apache License, Version 2.0 (the "License");
      9  * you may not use this file except in compliance with the License.
     10  * You may obtain a copy of the License at
     11  *
     12  *      http://www.apache.org/licenses/LICENSE-2.0
     13  *
     14  * Unless required by applicable law or agreed to in writing, software
     15  * distributed under the License is distributed on an "AS IS" BASIS,
     16  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     17  * See the License for the specific language governing permissions and
     18  * limitations under the License.
     19  */
     20 
     21 #include <fcntl.h>
     22 #include <stdint.h>
     23 #include <sys/types.h>
     24 #include <binder/Parcel.h>
     25 #include <binder/IBinder.h>
     26 #include <binder/IInterface.h>
     27 #include <binder/IPCThreadState.h>
     28 #include <utils/Errors.h>
     29 #include <private/android_filesystem_config.h>
     30 #include <IQService.h>
     31 
     32 #define QSERVICE_DEBUG 0
     33 
     34 using namespace android;
     35 using namespace qClient;
     36 
     37 // ---------------------------------------------------------------------------
     38 
     39 namespace qService {
     40 
     41 class BpQService : public BpInterface<IQService>
     42 {
     43 public:
     44     BpQService(const sp<IBinder>& impl)
     45         : BpInterface<IQService>(impl) {}
     46 
     47     virtual void connect(const sp<IQClient>& client) {
     48         ALOGD_IF(QSERVICE_DEBUG, "%s: connect client", __FUNCTION__);
     49         Parcel data, reply;
     50         data.writeInterfaceToken(IQService::getInterfaceDescriptor());
     51         data.writeStrongBinder(IInterface::asBinder(client));
     52         remote()->transact(CONNECT, data, &reply);
     53     }
     54 
     55     virtual android::status_t dispatch(uint32_t command, const Parcel* inParcel,
     56             Parcel* outParcel) {
     57         ALOGD_IF(QSERVICE_DEBUG, "%s: dispatch in:%p", __FUNCTION__, inParcel);
     58         status_t err = (status_t) android::FAILED_TRANSACTION;
     59         Parcel data;
     60         Parcel *reply = outParcel;
     61         data.writeInterfaceToken(IQService::getInterfaceDescriptor());
     62         if (inParcel && inParcel->dataSize() > 0)
     63             data.appendFrom(inParcel, 0, inParcel->dataSize());
     64         err = remote()->transact(command, data, reply);
     65         return err;
     66     }
     67 };
     68 
     69 IMPLEMENT_META_INTERFACE(QService, "android.display.IQService");
     70 
     71 // ----------------------------------------------------------------------
     72 
     73 static void getProcName(int pid, char *buf, int size);
     74 
     75 status_t BnQService::onTransact(
     76     uint32_t code, const Parcel& data, Parcel* reply, uint32_t flags)
     77 {
     78     ALOGD_IF(QSERVICE_DEBUG, "%s: code: %d", __FUNCTION__, code);
     79     // IPC should be from certain processes only
     80     IPCThreadState* ipc = IPCThreadState::self();
     81     const int callerPid = ipc->getCallingPid();
     82     const int callerUid = ipc->getCallingUid();
     83     const int MAX_BUF_SIZE = 1024;
     84     char callingProcName[MAX_BUF_SIZE] = {0};
     85 
     86     getProcName(callerPid, callingProcName, MAX_BUF_SIZE);
     87 
     88     const bool permission = (callerUid == AID_MEDIA ||
     89             callerUid == AID_GRAPHICS ||
     90             callerUid == AID_ROOT ||
     91             callerUid == AID_SYSTEM);
     92 
     93     if (code == CONNECT) {
     94         CHECK_INTERFACE(IQService, data, reply);
     95         if(callerUid != AID_GRAPHICS) {
     96             ALOGE("display.qservice CONNECT access denied: \
     97                     pid=%d uid=%d process=%s",
     98                     callerPid, callerUid, callingProcName);
     99             return PERMISSION_DENIED;
    100         }
    101         sp<IQClient> client =
    102                 interface_cast<IQClient>(data.readStrongBinder());
    103         connect(client);
    104         return NO_ERROR;
    105     } else if (code > COMMAND_LIST_START && code < COMMAND_LIST_END) {
    106         if(!permission) {
    107             ALOGE("display.qservice access denied: command=%d\
    108                   pid=%d uid=%d process=%s", code, callerPid,
    109                   callerUid, callingProcName);
    110             return PERMISSION_DENIED;
    111         }
    112         CHECK_INTERFACE(IQService, data, reply);
    113         dispatch(code, &data, reply);
    114         return NO_ERROR;
    115     } else {
    116         return BBinder::onTransact(code, data, reply, flags);
    117     }
    118 }
    119 
    120 //Helper
    121 static void getProcName(int pid, char *buf, int size) {
    122     int fd = -1;
    123     snprintf(buf, size, "/proc/%d/cmdline", pid);
    124     fd = open(buf, O_RDONLY);
    125     if (fd < 0) {
    126         strlcpy(buf, "Unknown", size);
    127     } else {
    128         ssize_t len = read(fd, buf, size - 1);
    129         if (len >= 0)
    130            buf[len] = 0;
    131 
    132         close(fd);
    133     }
    134 }
    135 
    136 }; // namespace qService
    137