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      1 /*
      2  * Copyright (C) 2008 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 //#define LOG_NDEBUG 0
     18 
     19 #include "JNIHelp.h"
     20 
     21 #include <fcntl.h>
     22 #include <sys/stat.h>
     23 #include <stdio.h>
     24 
     25 #include <utils/Log.h>
     26 
     27 #include <android_runtime/AndroidRuntime.h>
     28 
     29 namespace android
     30 {
     31 
     32 static struct parcel_file_descriptor_offsets_t
     33 {
     34     jfieldID mFileDescriptor;
     35 } gParcelFileDescriptorOffsets;
     36 
     37 static jobject android_os_ParcelFileDescriptor_getFileDescriptorFromFd(JNIEnv* env,
     38     jobject clazz, jint origfd)
     39 {
     40     int fd = dup(origfd);
     41     if (fd < 0) {
     42         jniThrowException(env, "java/io/IOException", strerror(errno));
     43         return NULL;
     44     }
     45     return jniCreateFileDescriptor(env, fd);
     46 }
     47 
     48 static jobject android_os_ParcelFileDescriptor_getFileDescriptorFromFdNoDup(JNIEnv* env,
     49     jobject clazz, jint fd)
     50 {
     51     return jniCreateFileDescriptor(env, fd);
     52 }
     53 
     54 static void android_os_ParcelFileDescriptor_createPipeNative(JNIEnv* env,
     55     jobject clazz, jobjectArray outFds)
     56 {
     57     int fds[2];
     58     if (pipe(fds) < 0) {
     59         int therr = errno;
     60         jniThrowException(env, "java/io/IOException", strerror(therr));
     61         return;
     62     }
     63 
     64     for (int i=0; i<2; i++) {
     65         jobject fdObj = jniCreateFileDescriptor(env, fds[i]);
     66         env->SetObjectArrayElement(outFds, i, fdObj);
     67     }
     68 }
     69 
     70 static jint getFd(JNIEnv* env, jobject clazz)
     71 {
     72     jobject descriptor = env->GetObjectField(clazz, gParcelFileDescriptorOffsets.mFileDescriptor);
     73     if (descriptor == NULL) return -1;
     74     return jniGetFDFromFileDescriptor(env, descriptor);
     75 }
     76 
     77 static jlong android_os_ParcelFileDescriptor_getStatSize(JNIEnv* env,
     78     jobject clazz)
     79 {
     80     jint fd = getFd(env, clazz);
     81     if (fd < 0) {
     82         jniThrowException(env, "java/lang/IllegalArgumentException", "bad file descriptor");
     83         return -1;
     84     }
     85 
     86     struct stat st;
     87     if (fstat(fd, &st) != 0) {
     88         return -1;
     89     }
     90 
     91     if (S_ISREG(st.st_mode) || S_ISLNK(st.st_mode)) {
     92         return st.st_size;
     93     }
     94 
     95     return -1;
     96 }
     97 
     98 static jlong android_os_ParcelFileDescriptor_seekTo(JNIEnv* env,
     99     jobject clazz, jlong pos)
    100 {
    101     jint fd = getFd(env, clazz);
    102     if (fd < 0) {
    103         jniThrowException(env, "java/lang/IllegalArgumentException", "bad file descriptor");
    104         return -1;
    105     }
    106 
    107     return lseek(fd, pos, SEEK_SET);
    108 }
    109 
    110 static jlong android_os_ParcelFileDescriptor_getFdNative(JNIEnv* env, jobject clazz)
    111 {
    112     jint fd = getFd(env, clazz);
    113     if (fd < 0) {
    114         jniThrowException(env, "java/lang/IllegalArgumentException", "bad file descriptor");
    115         return -1;
    116     }
    117 
    118     return fd;
    119 }
    120 
    121 static const JNINativeMethod gParcelFileDescriptorMethods[] = {
    122     {"getFileDescriptorFromFd", "(I)Ljava/io/FileDescriptor;",
    123         (void*)android_os_ParcelFileDescriptor_getFileDescriptorFromFd},
    124     {"getFileDescriptorFromFdNoDup", "(I)Ljava/io/FileDescriptor;",
    125         (void*)android_os_ParcelFileDescriptor_getFileDescriptorFromFdNoDup},
    126     {"createPipeNative", "([Ljava/io/FileDescriptor;)V",
    127         (void*)android_os_ParcelFileDescriptor_createPipeNative},
    128     {"getStatSize", "()J",
    129         (void*)android_os_ParcelFileDescriptor_getStatSize},
    130     {"seekTo", "(J)J",
    131         (void*)android_os_ParcelFileDescriptor_seekTo},
    132     {"getFdNative", "()I",
    133         (void*)android_os_ParcelFileDescriptor_getFdNative}
    134 };
    135 
    136 const char* const kParcelFileDescriptorPathName = "android/os/ParcelFileDescriptor";
    137 
    138 int register_android_os_ParcelFileDescriptor(JNIEnv* env)
    139 {
    140     jclass clazz = env->FindClass(kParcelFileDescriptorPathName);
    141     LOG_FATAL_IF(clazz == NULL, "Unable to find class android.os.ParcelFileDescriptor");
    142     gParcelFileDescriptorOffsets.mFileDescriptor = env->GetFieldID(clazz, "mFileDescriptor", "Ljava/io/FileDescriptor;");
    143     LOG_FATAL_IF(gParcelFileDescriptorOffsets.mFileDescriptor == NULL,
    144                  "Unable to find mFileDescriptor field in android.os.ParcelFileDescriptor");
    145 
    146     return AndroidRuntime::registerNativeMethods(
    147         env, kParcelFileDescriptorPathName,
    148         gParcelFileDescriptorMethods, NELEM(gParcelFileDescriptorMethods));
    149 }
    150 
    151 }
    152