/
libFieldAccessWatch.c
316 lines (261 loc) · 9.36 KB
/
libFieldAccessWatch.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
/*
* Copyright (c) 2018, 2021, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include "jvmti.h"
#include "jni.h"
#ifdef __cplusplus
extern "C" {
#endif
static jvmtiEnv *jvmti = NULL;
// valid while a test is executed
static jobject testResultObject = NULL;
static jclass testResultClass = NULL;
static jthread testThread = NULL;
static void reportError(const char *msg, int err) {
printf("%s, error: %d\n", msg, err);
}
// logs the notification and updates currentTestResult
static void handleNotification(JNIEnv *jni_env,
jthread thread,
jmethodID method,
jfieldID field,
jclass field_klass,
int modified,
jlocation location)
{
jvmtiError err;
char *name = NULL;
char *mname = NULL;
char *mgensig = NULL;
jclass methodClass = NULL;
char *csig = NULL;
if (testResultObject == NULL) {
// we are out of test
return;
}
if (!(*jni_env)->IsSameObject(jni_env, thread, testThread)) {
return; // skip events from unexpected threads
}
err = (*jvmti)->GetFieldName(jvmti, field_klass, field, &name, NULL, NULL);
if (err != JVMTI_ERROR_NONE) {
reportError("GetFieldName failed", err);
return;
}
err = (*jvmti)->GetMethodName(jvmti, method, &mname, NULL, &mgensig);
if (err != JVMTI_ERROR_NONE) {
reportError("GetMethodName failed", err);
return;
}
err = (*jvmti)->GetMethodDeclaringClass(jvmti, method, &methodClass);
if (err != JVMTI_ERROR_NONE) {
reportError("GetMethodDeclaringClass failed", err);
return;
}
err = (*jvmti)->GetClassSignature(jvmti, methodClass, &csig, NULL);
if (err != JVMTI_ERROR_NONE) {
reportError("GetClassSignature failed", err);
return;
}
printf("\"class: %s method: %s%s\" %s field: \"%s\", location: %d\n",
csig, mname, mgensig, modified ? "modified" : "accessed", name, (int)location);
// set TestResult
if (testResultObject != NULL && testResultClass != NULL) {
jfieldID fieldID;
// field names in TestResult are "<field_name>_access"/"<field_name>_modify"
char *fieldName = (char *)malloc(strlen(name) + 16);
strcpy(fieldName, name);
strcat(fieldName, modified ? "_modify" : "_access");
fieldID = (*jni_env)->GetFieldID(jni_env, testResultClass, fieldName, "Z");
if (fieldID != NULL) {
(*jni_env)->SetBooleanField(jni_env, testResultObject, fieldID, JNI_TRUE);
} else {
// the field is not interesting for the test
}
// clear any possible exception
(*jni_env)->ExceptionClear(jni_env);
free(fieldName);
}
(*jvmti)->Deallocate(jvmti, (unsigned char*)csig);
(*jvmti)->Deallocate(jvmti, (unsigned char*)mname);
(*jvmti)->Deallocate(jvmti, (unsigned char*)mgensig);
(*jvmti)->Deallocate(jvmti, (unsigned char*)name);
}
// recursively sets access and modification watchers for all
// fields of the object specified.
void setWatchers(JNIEnv *jni_env, const jobject obj)
{
jclass klass;
if (obj == NULL) {
return;
}
klass = (*jni_env)->GetObjectClass(jni_env, obj);
do {
jfieldID* klassFields = NULL;
jint fieldCount = 0;
int i;
jvmtiError err = (*jvmti)->GetClassFields(jvmti, klass, &fieldCount, &klassFields);
if (err != JVMTI_ERROR_NONE) {
reportError("Failed to get class fields", err);
return;
}
for (i = 0; i < fieldCount; ++i) {
char *sig = NULL;
err = (*jvmti)->SetFieldModificationWatch(jvmti, klass, klassFields[i]);
if (err != JVMTI_ERROR_NONE && err != JVMTI_ERROR_DUPLICATE) {
reportError("Failed to set field modification", err);
return;
}
err = (*jvmti)->SetFieldAccessWatch(jvmti, klass, klassFields[i]);
if (err != JVMTI_ERROR_NONE && err != JVMTI_ERROR_DUPLICATE) {
reportError("Failed to set field access", err);
return;
}
err = (*jvmti)->GetFieldName(jvmti, klass, klassFields[i], NULL, &sig, NULL);
if (sig) {
if (sig[0] == 'L') {
jobject fieldVal = (*jni_env)->GetObjectField(jni_env, obj, klassFields[i]);
setWatchers(jni_env, fieldVal);
}
(*jvmti)->Deallocate(jvmti, (unsigned char*)sig);
}
}
(*jvmti)->Deallocate(jvmti, (unsigned char*)klassFields);
klass = (*jni_env)->GetSuperclass(jni_env, klass);
} while (klass != NULL);
}
static void JNICALL
onFieldAccess(jvmtiEnv *jvmti_env,
JNIEnv* jni_env,
jthread thread,
jmethodID method,
jlocation location,
jclass field_klass,
jobject object,
jfieldID field)
{
handleNotification(jni_env, thread, method, field, field_klass, 0, location);
}
static void JNICALL
onFieldModification(jvmtiEnv *jvmti_env,
JNIEnv* jni_env,
jthread thread,
jmethodID method,
jlocation location,
jclass field_klass,
jobject object,
jfieldID field,
char signature_type,
jvalue new_value)
{
handleNotification(jni_env, thread, method, field, field_klass, 1, location);
if (signature_type == 'L') {
jobject newObject = new_value.l;
setWatchers(jni_env, newObject);
}
}
JNIEXPORT jint JNICALL
Agent_OnLoad(JavaVM *jvm, char *options, void *reserved)
{
jvmtiError err;
jvmtiCapabilities caps = {0};
jvmtiEventCallbacks callbacks = {0};
jint res = (*jvm)->GetEnv(jvm, (void **) &jvmti, JVMTI_VERSION_1_1);
if (res != JNI_OK || jvmti == NULL) {
reportError("GetEnv failed", res);
return JNI_ERR;
}
caps.can_generate_field_modification_events = 1;
caps.can_generate_field_access_events = 1;
caps.can_tag_objects = 1;
err = (*jvmti)->AddCapabilities(jvmti, &caps);
if (err != JVMTI_ERROR_NONE) {
reportError("Failed to set capabilities", err);
return JNI_ERR;
}
callbacks.FieldModification = &onFieldModification;
callbacks.FieldAccess = &onFieldAccess;
err = (*jvmti)->SetEventCallbacks(jvmti, &callbacks, sizeof(callbacks));
if (err != JVMTI_ERROR_NONE) {
reportError("Failed to set event callbacks", err);
return JNI_ERR;
}
err = (*jvmti)->SetEventNotificationMode(jvmti, JVMTI_ENABLE, JVMTI_EVENT_FIELD_ACCESS, NULL);
if (err != JVMTI_ERROR_NONE) {
reportError("Failed to set access notifications", err);
return JNI_ERR;
}
err = (*jvmti)->SetEventNotificationMode(jvmti, JVMTI_ENABLE, JVMTI_EVENT_FIELD_MODIFICATION, NULL);
if (err != JVMTI_ERROR_NONE) {
reportError("Failed to set modification notifications", err);
return JNI_ERR;
}
setbuf(stdout, NULL);
return JNI_OK;
}
JNIEXPORT jboolean JNICALL
Java_FieldAccessWatch_initWatchers(JNIEnv *env, jclass thisClass, jclass cls, jobject field, jthread thread)
{
jfieldID fieldId;
jvmtiError err;
if (jvmti == NULL) {
reportError("jvmti is NULL", 0);
return JNI_FALSE;
}
fieldId = (*env)->FromReflectedField(env, field);
err = (*jvmti)->SetFieldModificationWatch(jvmti, cls, fieldId);
if (err != JVMTI_ERROR_NONE) {
reportError("SetFieldModificationWatch failed", err);
return JNI_FALSE;
}
err = (*jvmti)->SetFieldAccessWatch(jvmti, cls, fieldId);
if (err != JVMTI_ERROR_NONE) {
reportError("SetFieldAccessWatch failed", err);
return JNI_FALSE;
}
testThread = (jthread)(*env)->NewGlobalRef(env, thread);
return JNI_TRUE;
}
JNIEXPORT jboolean JNICALL
Java_FieldAccessWatch_startTest(JNIEnv *env, jclass thisClass, jobject testResults)
{
testResultObject = (*env)->NewGlobalRef(env, testResults);
testResultClass = (jclass)(*env)->NewGlobalRef(env, (*env)->GetObjectClass(env, testResultObject));
return JNI_TRUE;
}
JNIEXPORT void JNICALL
Java_FieldAccessWatch_stopTest(JNIEnv *env, jclass thisClass)
{
if (testResultObject != NULL) {
(*env)->DeleteGlobalRef(env, testResultObject);
testResultObject = NULL;
}
if (testResultClass != NULL) {
(*env)->DeleteGlobalRef(env, testResultClass);
testResultClass = NULL;
}
}
#ifdef __cplusplus
}
#endif