1 /* //device/libs/android_runtime/android_util_FileObserver.cpp 2 ** 3 ** Copyright 2006, The Android Open Source Project 4 ** 5 ** Licensed under the Apache License, Version 2.0 (the "License"); 6 ** you may not use this file except in compliance with the License. 7 ** You may obtain a copy of the License at 8 ** 9 ** http://www.apache.org/licenses/LICENSE-2.0 10 ** 11 ** Unless required by applicable law or agreed to in writing, software 12 ** distributed under the License is distributed on an "AS IS" BASIS, 13 ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 ** See the License for the specific language governing permissions and 15 ** limitations under the License. 16 */ 17 18 #include "JNIHelp.h" 19 #include "jni.h" 20 #include "utils/Log.h" 21 #include "utils/misc.h" 22 #include "android_runtime/AndroidRuntime.h" 23 24 #include <stdio.h> 25 #include <stdlib.h> 26 #include <string.h> 27 #include <stdint.h> 28 #include <fcntl.h> 29 #include <sys/ioctl.h> 30 #include <errno.h> 31 32 #ifdef HAVE_INOTIFY 33 #include <sys/inotify.h> 34 #endif 35 36 namespace android { 37 38 static jmethodID method_onEvent; 39 40 static jint android_os_fileobserver_init(JNIEnv* env, jobject object) 41 { 42 #ifdef HAVE_INOTIFY 43 44 return (jint)inotify_init(); 45 46 #else // HAVE_INOTIFY 47 48 return -1; 49 50 #endif // HAVE_INOTIFY 51 } 52 53 static void android_os_fileobserver_observe(JNIEnv* env, jobject object, jint fd) 54 { 55 #ifdef HAVE_INOTIFY 56 57 char event_buf[512]; 58 struct inotify_event* event; 59 60 while (1) 61 { 62 int event_pos = 0; 63 int num_bytes = read(fd, event_buf, sizeof(event_buf)); 64 65 if (num_bytes < (int)sizeof(*event)) 66 { 67 if (errno == EINTR) 68 continue; 69 70 ALOGE("***** ERROR! android_os_fileobserver_observe() got a short event!"); 71 return; 72 } 73 74 while (num_bytes >= (int)sizeof(*event)) 75 { 76 int event_size; 77 event = (struct inotify_event *)(event_buf + event_pos); 78 79 jstring path = NULL; 80 81 if (event->len > 0) 82 { 83 path = env->NewStringUTF(event->name); 84 } 85 86 env->CallVoidMethod(object, method_onEvent, event->wd, event->mask, path); 87 if (env->ExceptionCheck()) { 88 env->ExceptionDescribe(); 89 env->ExceptionClear(); 90 } 91 if (path != NULL) 92 { 93 env->DeleteLocalRef(path); 94 } 95 96 event_size = sizeof(*event) + event->len; 97 num_bytes -= event_size; 98 event_pos += event_size; 99 } 100 } 101 102 #endif // HAVE_INOTIFY 103 } 104 105 static jint android_os_fileobserver_startWatching(JNIEnv* env, jobject object, jint fd, jstring pathString, jint mask) 106 { 107 int res = -1; 108 109 #ifdef HAVE_INOTIFY 110 111 if (fd >= 0) 112 { 113 const char* path = env->GetStringUTFChars(pathString, NULL); 114 115 res = inotify_add_watch(fd, path, mask); 116 117 env->ReleaseStringUTFChars(pathString, path); 118 } 119 120 #endif // HAVE_INOTIFY 121 122 return res; 123 } 124 125 static void android_os_fileobserver_stopWatching(JNIEnv* env, jobject object, jint fd, jint wfd) 126 { 127 #ifdef HAVE_INOTIFY 128 129 inotify_rm_watch((int)fd, (uint32_t)wfd); 130 131 #endif // HAVE_INOTIFY 132 } 133 134 static JNINativeMethod sMethods[] = { 135 /* name, signature, funcPtr */ 136 { "init", "()I", (void*)android_os_fileobserver_init }, 137 { "observe", "(I)V", (void*)android_os_fileobserver_observe }, 138 { "startWatching", "(ILjava/lang/String;I)I", (void*)android_os_fileobserver_startWatching }, 139 { "stopWatching", "(II)V", (void*)android_os_fileobserver_stopWatching } 140 141 }; 142 143 int register_android_os_FileObserver(JNIEnv* env) 144 { 145 jclass clazz; 146 147 clazz = env->FindClass("android/os/FileObserver$ObserverThread"); 148 149 if (clazz == NULL) 150 { 151 ALOGE("Can't find android/os/FileObserver$ObserverThread"); 152 return -1; 153 } 154 155 method_onEvent = env->GetMethodID(clazz, "onEvent", "(IILjava/lang/String;)V"); 156 if (method_onEvent == NULL) 157 { 158 ALOGE("Can't find FileObserver.onEvent(int, int, String)"); 159 return -1; 160 } 161 162 return AndroidRuntime::registerNativeMethods(env, "android/os/FileObserver$ObserverThread", sMethods, NELEM(sMethods)); 163 } 164 165 } /* namespace android */ 166