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 "core_jni_helpers.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 #if defined(__linux__)
33 #include <sys/inotify.h>
34 #endif
35
36 namespace android {
37
38 static jmethodID method_onEvent;
39
android_os_fileobserver_init(JNIEnv * env,jobject object)40 static jint android_os_fileobserver_init(JNIEnv* env, jobject object)
41 {
42 #if defined(__linux__)
43 return (jint)inotify_init();
44 #else
45 return -1;
46 #endif
47 }
48
android_os_fileobserver_observe(JNIEnv * env,jobject object,jint fd)49 static void android_os_fileobserver_observe(JNIEnv* env, jobject object, jint fd)
50 {
51 #if defined(__linux__)
52
53 char event_buf[512];
54 struct inotify_event* event;
55
56 while (1)
57 {
58 int event_pos = 0;
59 int num_bytes = read(fd, event_buf, sizeof(event_buf));
60
61 if (num_bytes < (int)sizeof(*event))
62 {
63 if (errno == EINTR)
64 continue;
65
66 ALOGE("***** ERROR! android_os_fileobserver_observe() got a short event!");
67 return;
68 }
69
70 while (num_bytes >= (int)sizeof(*event))
71 {
72 int event_size;
73 event = (struct inotify_event *)(event_buf + event_pos);
74
75 jstring path = NULL;
76
77 if (event->len > 0)
78 {
79 path = env->NewStringUTF(event->name);
80 }
81
82 env->CallVoidMethod(object, method_onEvent, event->wd, event->mask, path);
83 if (env->ExceptionCheck()) {
84 env->ExceptionDescribe();
85 env->ExceptionClear();
86 }
87 if (path != NULL)
88 {
89 env->DeleteLocalRef(path);
90 }
91
92 event_size = sizeof(*event) + event->len;
93 num_bytes -= event_size;
94 event_pos += event_size;
95 }
96 }
97
98 #endif
99 }
100
android_os_fileobserver_startWatching(JNIEnv * env,jobject object,jint fd,jstring pathString,jint mask)101 static jint android_os_fileobserver_startWatching(JNIEnv* env, jobject object, jint fd, jstring pathString, jint mask)
102 {
103 int res = -1;
104
105 #if defined(__linux__)
106
107 if (fd >= 0)
108 {
109 const char* path = env->GetStringUTFChars(pathString, NULL);
110
111 res = inotify_add_watch(fd, path, mask);
112
113 env->ReleaseStringUTFChars(pathString, path);
114 }
115
116 #endif
117
118 return res;
119 }
120
android_os_fileobserver_stopWatching(JNIEnv * env,jobject object,jint fd,jint wfd)121 static void android_os_fileobserver_stopWatching(JNIEnv* env, jobject object, jint fd, jint wfd)
122 {
123 #if defined(__linux__)
124
125 inotify_rm_watch((int)fd, (uint32_t)wfd);
126
127 #endif
128 }
129
130 static const JNINativeMethod sMethods[] = {
131 /* name, signature, funcPtr */
132 { "init", "()I", (void*)android_os_fileobserver_init },
133 { "observe", "(I)V", (void*)android_os_fileobserver_observe },
134 { "startWatching", "(ILjava/lang/String;I)I", (void*)android_os_fileobserver_startWatching },
135 { "stopWatching", "(II)V", (void*)android_os_fileobserver_stopWatching }
136
137 };
138
register_android_os_FileObserver(JNIEnv * env)139 int register_android_os_FileObserver(JNIEnv* env)
140 {
141 jclass clazz = FindClassOrDie(env, "android/os/FileObserver$ObserverThread");
142
143 method_onEvent = GetMethodIDOrDie(env, clazz, "onEvent", "(IILjava/lang/String;)V");
144
145 return RegisterMethodsOrDie(env, "android/os/FileObserver$ObserverThread", sMethods,
146 NELEM(sMethods));
147 }
148
149 } /* namespace android */
150