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_TAG "MemoryFile" 18 #include <utils/Log.h> 19 20 #include <cutils/ashmem.h> 21 #include <android_runtime/AndroidRuntime.h> 22 #include "JNIHelp.h" 23 #include <unistd.h> 24 #include <sys/mman.h> 25 26 27 namespace android { 28 29 static jobject android_os_MemoryFile_open(JNIEnv* env, jobject clazz, jstring name, jint length) 30 { 31 const char* namestr = (name ? env->GetStringUTFChars(name, NULL) : NULL); 32 33 int result = ashmem_create_region(namestr, length); 34 35 if (name) 36 env->ReleaseStringUTFChars(name, namestr); 37 38 if (result < 0) { 39 jniThrowException(env, "java/io/IOException", "ashmem_create_region failed"); 40 return NULL; 41 } 42 43 return jniCreateFileDescriptor(env, result); 44 } 45 46 static jint android_os_MemoryFile_mmap(JNIEnv* env, jobject clazz, jobject fileDescriptor, 47 jint length, jint prot) 48 { 49 int fd = jniGetFDFromFileDescriptor(env, fileDescriptor); 50 jint result = (jint)mmap(NULL, length, prot, MAP_SHARED, fd, 0); 51 if (!result) 52 jniThrowException(env, "java/io/IOException", "mmap failed"); 53 return result; 54 } 55 56 static void android_os_MemoryFile_munmap(JNIEnv* env, jobject clazz, jint addr, jint length) 57 { 58 int result = munmap((void *)addr, length); 59 if (result < 0) 60 jniThrowException(env, "java/io/IOException", "munmap failed"); 61 } 62 63 static void android_os_MemoryFile_close(JNIEnv* env, jobject clazz, jobject fileDescriptor) 64 { 65 int fd = jniGetFDFromFileDescriptor(env, fileDescriptor); 66 if (fd >= 0) { 67 jniSetFileDescriptorOfFD(env, fileDescriptor, -1); 68 close(fd); 69 } 70 } 71 72 static jint android_os_MemoryFile_read(JNIEnv* env, jobject clazz, 73 jobject fileDescriptor, jint address, jbyteArray buffer, jint srcOffset, jint destOffset, 74 jint count, jboolean unpinned) 75 { 76 int fd = jniGetFDFromFileDescriptor(env, fileDescriptor); 77 if (unpinned && ashmem_pin_region(fd, 0, 0) == ASHMEM_WAS_PURGED) { 78 ashmem_unpin_region(fd, 0, 0); 79 jniThrowException(env, "java/io/IOException", "ashmem region was purged"); 80 return -1; 81 } 82 83 env->SetByteArrayRegion(buffer, destOffset, count, (const jbyte *)address + srcOffset); 84 85 if (unpinned) { 86 ashmem_unpin_region(fd, 0, 0); 87 } 88 return count; 89 } 90 91 static jint android_os_MemoryFile_write(JNIEnv* env, jobject clazz, 92 jobject fileDescriptor, jint address, jbyteArray buffer, jint srcOffset, jint destOffset, 93 jint count, jboolean unpinned) 94 { 95 int fd = jniGetFDFromFileDescriptor(env, fileDescriptor); 96 if (unpinned && ashmem_pin_region(fd, 0, 0) == ASHMEM_WAS_PURGED) { 97 ashmem_unpin_region(fd, 0, 0); 98 jniThrowException(env, "java/io/IOException", "ashmem region was purged"); 99 return -1; 100 } 101 102 env->GetByteArrayRegion(buffer, srcOffset, count, (jbyte *)address + destOffset); 103 104 if (unpinned) { 105 ashmem_unpin_region(fd, 0, 0); 106 } 107 return count; 108 } 109 110 static void android_os_MemoryFile_pin(JNIEnv* env, jobject clazz, jobject fileDescriptor, jboolean pin) 111 { 112 int fd = jniGetFDFromFileDescriptor(env, fileDescriptor); 113 int result = (pin ? ashmem_pin_region(fd, 0, 0) : ashmem_unpin_region(fd, 0, 0)); 114 if (result < 0) { 115 jniThrowException(env, "java/io/IOException", NULL); 116 } 117 } 118 119 static jint android_os_MemoryFile_get_size(JNIEnv* env, jobject clazz, 120 jobject fileDescriptor) { 121 int fd = jniGetFDFromFileDescriptor(env, fileDescriptor); 122 // Use ASHMEM_GET_SIZE to find out if the fd refers to an ashmem region. 123 // ASHMEM_GET_SIZE should succeed for all ashmem regions, and the kernel 124 // should return ENOTTY for all other valid file descriptors 125 int result = ashmem_get_size_region(fd); 126 if (result < 0) { 127 if (errno == ENOTTY) { 128 // ENOTTY means that the ioctl does not apply to this object, 129 // i.e., it is not an ashmem region. 130 return (jint) -1; 131 } 132 // Some other error, throw exception 133 jniThrowIOException(env, errno); 134 return (jint) -1; 135 } 136 return (jint) result; 137 } 138 139 static const JNINativeMethod methods[] = { 140 {"native_open", "(Ljava/lang/String;I)Ljava/io/FileDescriptor;", (void*)android_os_MemoryFile_open}, 141 {"native_mmap", "(Ljava/io/FileDescriptor;II)I", (void*)android_os_MemoryFile_mmap}, 142 {"native_munmap", "(II)V", (void*)android_os_MemoryFile_munmap}, 143 {"native_close", "(Ljava/io/FileDescriptor;)V", (void*)android_os_MemoryFile_close}, 144 {"native_read", "(Ljava/io/FileDescriptor;I[BIIIZ)I", (void*)android_os_MemoryFile_read}, 145 {"native_write", "(Ljava/io/FileDescriptor;I[BIIIZ)V", (void*)android_os_MemoryFile_write}, 146 {"native_pin", "(Ljava/io/FileDescriptor;Z)V", (void*)android_os_MemoryFile_pin}, 147 {"native_get_size", "(Ljava/io/FileDescriptor;)I", 148 (void*)android_os_MemoryFile_get_size} 149 }; 150 151 int register_android_os_MemoryFile(JNIEnv* env) 152 { 153 return AndroidRuntime::registerNativeMethods( 154 env, "android/os/MemoryFile", 155 methods, NELEM(methods)); 156 } 157 158 } 159
