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
36namespace android {
37
38static jmethodID method_onEvent;
39
40static 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
53static 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
105static 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
125static 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
134static 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
143int 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