android_os_ParcelFileDescriptor.cpp revision 939461300a0283a9f370a0425d4061d32b36f952 
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
29namespace android
30{
31
32static struct parcel_file_descriptor_offsets_t
33{
34    jfieldID mFileDescriptor;
35} gParcelFileDescriptorOffsets;
36
37static 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
48static jobject android_os_ParcelFileDescriptor_getFileDescriptorFromFdNoDup(JNIEnv* env,
49    jobject clazz, jint fd)
50{
51    return jniCreateFileDescriptor(env, fd);
52}
53
54static 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
70static 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
77static 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
98static 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
110static 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
121static 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
136const char* const kParcelFileDescriptorPathName = "android/os/ParcelFileDescriptor";
137
138int 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