Svet Ganov | 53a441c | 2016-04-19 19:38:00 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2016 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 | |
Svet Ganov | 53a441c | 2016-04-19 19:38:00 -0700 | [diff] [blame] | 17 | #include "core_jni_helpers.h" |
| 18 | #include <cutils/ashmem.h> |
Svetoslav Ganov | 04df738 | 2016-05-10 18:55:47 -0700 | [diff] [blame] | 19 | #include <linux/ashmem.h> |
Svet Ganov | 53a441c | 2016-04-19 19:38:00 -0700 | [diff] [blame] | 20 | #include <sys/mman.h> |
| 21 | |
| 22 | namespace android { |
| 23 | |
| 24 | static jint android_util_MemoryIntArray_create(JNIEnv* env, jobject clazz, jstring name, |
| 25 | jint size) |
| 26 | { |
| 27 | if (name == NULL) { |
| 28 | jniThrowException(env, "java/io/IOException", "bad name"); |
| 29 | return -1; |
| 30 | } |
| 31 | |
| 32 | if (size <= 0) { |
| 33 | jniThrowException(env, "java/io/IOException", "bad size"); |
| 34 | return -1; |
| 35 | } |
| 36 | |
| 37 | const char* nameStr = env->GetStringUTFChars(name, NULL); |
| 38 | const int ashmemSize = sizeof(std::atomic_int) * size; |
| 39 | int fd = ashmem_create_region(nameStr, ashmemSize); |
| 40 | env->ReleaseStringUTFChars(name, nameStr); |
| 41 | |
| 42 | if (fd < 0) { |
| 43 | jniThrowException(env, "java/io/IOException", "ashmem creation failed"); |
| 44 | return -1; |
| 45 | } |
| 46 | |
Svet Ganov | 53a441c | 2016-04-19 19:38:00 -0700 | [diff] [blame] | 47 | int setProtResult = ashmem_set_prot_region(fd, PROT_READ | PROT_WRITE); |
| 48 | if (setProtResult < 0) { |
| 49 | jniThrowException(env, "java/io/IOException", "cannot set ashmem prot mode"); |
| 50 | return -1; |
| 51 | } |
| 52 | |
| 53 | return fd; |
| 54 | } |
| 55 | |
| 56 | static jlong android_util_MemoryIntArray_open(JNIEnv* env, jobject clazz, jint fd, |
| 57 | jboolean owner, jboolean writable) |
| 58 | { |
| 59 | if (fd < 0) { |
| 60 | jniThrowException(env, "java/io/IOException", "bad file descriptor"); |
| 61 | return -1; |
| 62 | } |
| 63 | |
| 64 | int ashmemSize = ashmem_get_size_region(fd); |
| 65 | if (ashmemSize <= 0) { |
| 66 | jniThrowException(env, "java/io/IOException", "bad ashmem size"); |
| 67 | return -1; |
| 68 | } |
| 69 | |
| 70 | int protMode = (owner || writable) ? (PROT_READ | PROT_WRITE) : PROT_READ; |
| 71 | void* ashmemAddr = mmap(NULL, ashmemSize, protMode, MAP_SHARED, fd, 0); |
| 72 | if (ashmemAddr == MAP_FAILED) { |
| 73 | jniThrowException(env, "java/io/IOException", "cannot mmap ashmem"); |
| 74 | return -1; |
| 75 | } |
| 76 | |
| 77 | if (owner) { |
| 78 | int size = ashmemSize / sizeof(std::atomic_int); |
| 79 | new (ashmemAddr) std::atomic_int[size]; |
| 80 | } |
| 81 | |
| 82 | if (owner && !writable) { |
| 83 | int setProtResult = ashmem_set_prot_region(fd, PROT_READ); |
| 84 | if (setProtResult < 0) { |
| 85 | jniThrowException(env, "java/io/IOException", "cannot set ashmem prot mode"); |
| 86 | return -1; |
| 87 | } |
| 88 | } |
| 89 | |
| 90 | return reinterpret_cast<jlong>(ashmemAddr); |
| 91 | } |
| 92 | |
| 93 | static void android_util_MemoryIntArray_close(JNIEnv* env, jobject clazz, jint fd, |
| 94 | jlong ashmemAddr, jboolean owner) |
| 95 | { |
| 96 | if (fd < 0) { |
| 97 | jniThrowException(env, "java/io/IOException", "bad file descriptor"); |
| 98 | return; |
| 99 | } |
| 100 | |
| 101 | int ashmemSize = ashmem_get_size_region(fd); |
| 102 | if (ashmemSize <= 0) { |
| 103 | jniThrowException(env, "java/io/IOException", "bad ashmem size"); |
| 104 | return; |
| 105 | } |
| 106 | |
| 107 | int unmapResult = munmap(reinterpret_cast<void *>(ashmemAddr), ashmemSize); |
| 108 | if (unmapResult < 0) { |
| 109 | jniThrowException(env, "java/io/IOException", "munmap failed"); |
| 110 | return; |
| 111 | } |
| 112 | |
| 113 | // We don't deallocate the atomic ints we created with placement new in the ashmem |
| 114 | // region as the kernel we reclaim all pages when the ashmem region is destroyed. |
| 115 | if (owner && (ashmem_unpin_region(fd, 0, 0) != ASHMEM_IS_UNPINNED)) { |
| 116 | jniThrowException(env, "java/io/IOException", "ashmem unpinning failed"); |
| 117 | return; |
| 118 | } |
| 119 | |
| 120 | close(fd); |
| 121 | } |
| 122 | |
| 123 | static jint android_util_MemoryIntArray_get(JNIEnv* env, jobject clazz, |
| 124 | jint fd, jlong address, jint index, jboolean owner) |
| 125 | { |
| 126 | if (fd < 0) { |
| 127 | jniThrowException(env, "java/io/IOException", "bad file descriptor"); |
| 128 | return -1; |
| 129 | } |
| 130 | |
Svetoslav Ganov | 04df738 | 2016-05-10 18:55:47 -0700 | [diff] [blame] | 131 | if (ashmem_pin_region(fd, 0, 0) == ASHMEM_WAS_PURGED) { |
| 132 | jniThrowException(env, "java/io/IOException", "ashmem region was purged"); |
| 133 | return -1; |
Svet Ganov | 53a441c | 2016-04-19 19:38:00 -0700 | [diff] [blame] | 134 | } |
| 135 | |
| 136 | std::atomic_int* value = reinterpret_cast<std::atomic_int*>(address) + index; |
Svetoslav Ganov | 04df738 | 2016-05-10 18:55:47 -0700 | [diff] [blame] | 137 | return value->load(std::memory_order_relaxed); |
Svet Ganov | 53a441c | 2016-04-19 19:38:00 -0700 | [diff] [blame] | 138 | } |
| 139 | |
| 140 | static void android_util_MemoryIntArray_set(JNIEnv* env, jobject clazz, |
| 141 | jint fd, jlong address, jint index, jint newValue, jboolean owner) |
| 142 | { |
| 143 | if (fd < 0) { |
| 144 | jniThrowException(env, "java/io/IOException", "bad file descriptor"); |
| 145 | return; |
| 146 | } |
| 147 | |
Svetoslav Ganov | 04df738 | 2016-05-10 18:55:47 -0700 | [diff] [blame] | 148 | if (ashmem_pin_region(fd, 0, 0) == ASHMEM_WAS_PURGED) { |
| 149 | jniThrowException(env, "java/io/IOException", "ashmem region was purged"); |
| 150 | return; |
Svet Ganov | 53a441c | 2016-04-19 19:38:00 -0700 | [diff] [blame] | 151 | } |
| 152 | |
| 153 | std::atomic_int* value = reinterpret_cast<std::atomic_int*>(address) + index; |
| 154 | value->store(newValue, std::memory_order_relaxed); |
Svet Ganov | 53a441c | 2016-04-19 19:38:00 -0700 | [diff] [blame] | 155 | } |
| 156 | |
| 157 | static jint android_util_MemoryIntArray_size(JNIEnv* env, jobject clazz, jint fd) { |
| 158 | if (fd < 0) { |
| 159 | jniThrowException(env, "java/io/IOException", "bad file descriptor"); |
| 160 | return -1; |
| 161 | } |
| 162 | |
| 163 | // Use ASHMEM_GET_SIZE to find out if the fd refers to an ashmem region. |
| 164 | // ASHMEM_GET_SIZE should succeed for all ashmem regions, and the kernel |
| 165 | // should return ENOTTY for all other valid file descriptors |
| 166 | int ashmemSize = ashmem_get_size_region(fd); |
| 167 | if (ashmemSize < 0) { |
| 168 | if (errno == ENOTTY) { |
| 169 | // ENOTTY means that the ioctl does not apply to this object, |
| 170 | // i.e., it is not an ashmem region. |
| 171 | return -1; |
| 172 | } |
| 173 | // Some other error, throw exception |
| 174 | jniThrowIOException(env, errno); |
| 175 | return -1; |
| 176 | } |
| 177 | return ashmemSize / sizeof(std::atomic_int); |
| 178 | } |
| 179 | |
| 180 | static const JNINativeMethod methods[] = { |
| 181 | {"nativeCreate", "(Ljava/lang/String;I)I", (void*)android_util_MemoryIntArray_create}, |
| 182 | {"nativeOpen", "(IZZ)J", (void*)android_util_MemoryIntArray_open}, |
| 183 | {"nativeClose", "(IJZ)V", (void*)android_util_MemoryIntArray_close}, |
| 184 | {"nativeGet", "(IJIZ)I", (void*)android_util_MemoryIntArray_get}, |
| 185 | {"nativeSet", "(IJIIZ)V", (void*) android_util_MemoryIntArray_set}, |
| 186 | {"nativeSize", "(I)I", (void*) android_util_MemoryIntArray_size}, |
| 187 | }; |
| 188 | |
| 189 | int register_android_util_MemoryIntArray(JNIEnv* env) |
| 190 | { |
| 191 | return RegisterMethodsOrDie(env, "android/util/MemoryIntArray", methods, NELEM(methods)); |
| 192 | } |
| 193 | |
| 194 | } |