/* * Copyright (c) 2003, 2010, 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 "precompiled.hpp" #include "classfile/systemDictionary.hpp" #include "jvmtifiles/jvmtiEnv.hpp" #include "oops/objArrayKlass.hpp" #include "oops/objArrayOop.hpp" #include "prims/jvmtiEnvBase.hpp" #include "prims/jvmtiEventController.inline.hpp" #include "prims/jvmtiExtensions.hpp" #include "prims/jvmtiImpl.hpp" #include "prims/jvmtiManageCapabilities.hpp" #include "prims/jvmtiTagMap.hpp" #include "prims/jvmtiThreadState.inline.hpp" #include "runtime/biasedLocking.hpp" #include "runtime/deoptimization.hpp" #include "runtime/interfaceSupport.hpp" #include "runtime/jfieldIDWorkaround.hpp" #include "runtime/objectMonitor.hpp" #include "runtime/objectMonitor.inline.hpp" #include "runtime/signature.hpp" #include "runtime/vframe.hpp" #include "runtime/vframe_hp.hpp" #include "runtime/vmThread.hpp" #include "runtime/vm_operations.hpp" /////////////////////////////////////////////////////////////// // // JvmtiEnvBase // JvmtiEnvBase* JvmtiEnvBase::_head_environment = NULL; bool JvmtiEnvBase::_globally_initialized = false; volatile bool JvmtiEnvBase::_needs_clean_up = false; jvmtiPhase JvmtiEnvBase::_phase = JVMTI_PHASE_PRIMORDIAL; volatile int JvmtiEnvBase::_dying_thread_env_iteration_count = 0; extern jvmtiInterface_1_ jvmti_Interface; extern jvmtiInterface_1_ jvmtiTrace_Interface; // perform initializations that must occur before any JVMTI environments // are released but which should only be initialized once (no matter // how many environments are created). void JvmtiEnvBase::globally_initialize() { assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check"); assert(_globally_initialized == false, "bad call"); JvmtiManageCapabilities::initialize(); #ifndef JVMTI_KERNEL // register extension functions and events JvmtiExtensions::register_extensions(); #endif // !JVMTI_KERNEL #ifdef JVMTI_TRACE JvmtiTrace::initialize(); #endif _globally_initialized = true; } void JvmtiEnvBase::initialize() { assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check"); // Add this environment to the end of the environment list (order is important) { // This block of code must not contain any safepoints, as list deallocation // (which occurs at a safepoint) cannot occur simultaneously with this list // addition. Note: No_Safepoint_Verifier cannot, currently, be used before // threads exist. JvmtiEnvIterator it; JvmtiEnvBase *previous_env = NULL; for (JvmtiEnvBase* env = it.first(); env != NULL; env = it.next(env)) { previous_env = env; } if (previous_env == NULL) { _head_environment = this; } else { previous_env->set_next_environment(this); } } if (_globally_initialized == false) { globally_initialize(); } } bool JvmtiEnvBase::is_valid() { jint value = 0; // This object might not be a JvmtiEnvBase so we can't assume // the _magic field is properly aligned. Get the value in a safe // way and then check against JVMTI_MAGIC. switch (sizeof(_magic)) { case 2: value = Bytes::get_native_u2((address)&_magic); break; case 4: value = Bytes::get_native_u4((address)&_magic); break; case 8: value = Bytes::get_native_u8((address)&_magic); break; default: guarantee(false, "_magic field is an unexpected size"); } return value == JVMTI_MAGIC; } bool JvmtiEnvBase::use_version_1_0_semantics() { int major, minor, micro; JvmtiExport::decode_version_values(_version, &major, &minor, µ); return major == 1 && minor == 0; // micro version doesn't matter here } bool JvmtiEnvBase::use_version_1_1_semantics() { int major, minor, micro; JvmtiExport::decode_version_values(_version, &major, &minor, µ); return major == 1 && minor == 1; // micro version doesn't matter here } bool JvmtiEnvBase::use_version_1_2_semantics() { int major, minor, micro; JvmtiExport::decode_version_values(_version, &major, &minor, µ); return major == 1 && minor == 2; // micro version doesn't matter here } JvmtiEnvBase::JvmtiEnvBase(jint version) : _env_event_enable() { _version = version; _env_local_storage = NULL; _tag_map = NULL; _native_method_prefix_count = 0; _native_method_prefixes = NULL; _next = NULL; _class_file_load_hook_ever_enabled = false; // Moot since ClassFileLoadHook not yet enabled. // But "true" will give a more predictable ClassFileLoadHook behavior // for environment creation during ClassFileLoadHook. _is_retransformable = true; // all callbacks initially NULL memset(&_event_callbacks,0,sizeof(jvmtiEventCallbacks)); // all capabilities initially off memset(&_current_capabilities, 0, sizeof(_current_capabilities)); // all prohibited capabilities initially off memset(&_prohibited_capabilities, 0, sizeof(_prohibited_capabilities)); _magic = JVMTI_MAGIC; JvmtiEventController::env_initialize((JvmtiEnv*)this); #ifdef JVMTI_TRACE _jvmti_external.functions = TraceJVMTI != NULL ? &jvmtiTrace_Interface : &jvmti_Interface; #else _jvmti_external.functions = &jvmti_Interface; #endif } void JvmtiEnvBase::dispose() { #ifdef JVMTI_TRACE JvmtiTrace::shutdown(); #endif // Dispose of event info and let the event controller call us back // in a locked state (env_dispose, below) JvmtiEventController::env_dispose(this); } void JvmtiEnvBase::env_dispose() { assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check"); // We have been entered with all events disabled on this environment. // A race to re-enable events (by setting callbacks) is prevented by // checking for a valid environment when setting callbacks (while // holding the JvmtiThreadState_lock). // Mark as invalid. _magic = DISPOSED_MAGIC; // Relinquish all capabilities. jvmtiCapabilities *caps = get_capabilities(); JvmtiManageCapabilities::relinquish_capabilities(caps, caps, caps); // Same situation as with events (see above) set_native_method_prefixes(0, NULL); #ifndef JVMTI_KERNEL JvmtiTagMap* tag_map_to_deallocate = _tag_map; set_tag_map(NULL); // A tag map can be big, deallocate it now if (tag_map_to_deallocate != NULL) { delete tag_map_to_deallocate; } #endif // !JVMTI_KERNEL _needs_clean_up = true; } JvmtiEnvBase::~JvmtiEnvBase() { assert(SafepointSynchronize::is_at_safepoint(), "sanity check"); // There is a small window of time during which the tag map of a // disposed environment could have been reallocated. // Make sure it is gone. #ifndef JVMTI_KERNEL JvmtiTagMap* tag_map_to_deallocate = _tag_map; set_tag_map(NULL); // A tag map can be big, deallocate it now if (tag_map_to_deallocate != NULL) { delete tag_map_to_deallocate; } #endif // !JVMTI_KERNEL _magic = BAD_MAGIC; } void JvmtiEnvBase::periodic_clean_up() { assert(SafepointSynchronize::is_at_safepoint(), "sanity check"); // JvmtiEnvBase reference is saved in JvmtiEnvThreadState. So // clean up JvmtiThreadState before deleting JvmtiEnv pointer. JvmtiThreadState::periodic_clean_up(); // Unlink all invalid environments from the list of environments // and deallocate them JvmtiEnvIterator it; JvmtiEnvBase* previous_env = NULL; JvmtiEnvBase* env = it.first(); while (env != NULL) { if (env->is_valid()) { previous_env = env; env = it.next(env); } else { // This one isn't valid, remove it from the list and deallocate it JvmtiEnvBase* defunct_env = env; env = it.next(env); if (previous_env == NULL) { _head_environment = env; } else { previous_env->set_next_environment(env); } delete defunct_env; } } } void JvmtiEnvBase::check_for_periodic_clean_up() { assert(SafepointSynchronize::is_at_safepoint(), "sanity check"); class ThreadInsideIterationClosure: public ThreadClosure { private: bool _inside; public: ThreadInsideIterationClosure() : _inside(false) {}; void do_thread(Thread* thread) { _inside |= thread->is_inside_jvmti_env_iteration(); } bool is_inside_jvmti_env_iteration() { return _inside; } }; if (_needs_clean_up) { // Check if we are currently iterating environment, // deallocation should not occur if we are ThreadInsideIterationClosure tiic; Threads::threads_do(&tiic); if (!tiic.is_inside_jvmti_env_iteration() && !is_inside_dying_thread_env_iteration()) { _needs_clean_up = false; JvmtiEnvBase::periodic_clean_up(); } } } void JvmtiEnvBase::record_first_time_class_file_load_hook_enabled() { assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check"); if (!_class_file_load_hook_ever_enabled) { _class_file_load_hook_ever_enabled = true; if (get_capabilities()->can_retransform_classes) { _is_retransformable = true; } else { _is_retransformable = false; // cannot add retransform capability after ClassFileLoadHook has been enabled get_prohibited_capabilities()->can_retransform_classes = 1; } } } void JvmtiEnvBase::record_class_file_load_hook_enabled() { if (!_class_file_load_hook_ever_enabled) { if (Threads::number_of_threads() == 0) { record_first_time_class_file_load_hook_enabled(); } else { MutexLocker mu(JvmtiThreadState_lock); record_first_time_class_file_load_hook_enabled(); } } } jvmtiError JvmtiEnvBase::set_native_method_prefixes(jint prefix_count, char** prefixes) { assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check"); int old_prefix_count = get_native_method_prefix_count(); char **old_prefixes = get_native_method_prefixes(); // allocate and install the new prefixex if (prefix_count == 0 || !is_valid()) { _native_method_prefix_count = 0; _native_method_prefixes = NULL; } else { // there are prefixes, allocate an array to hold them, and fill it char** new_prefixes = (char**)os::malloc((prefix_count) * sizeof(char*)); if (new_prefixes == NULL) { return JVMTI_ERROR_OUT_OF_MEMORY; } for (int i = 0; i < prefix_count; i++) { char* prefix = prefixes[i]; if (prefix == NULL) { for (int j = 0; j < (i-1); j++) { os::free(new_prefixes[j]); } os::free(new_prefixes); return JVMTI_ERROR_NULL_POINTER; } prefix = os::strdup(prefixes[i]); if (prefix == NULL) { for (int j = 0; j < (i-1); j++) { os::free(new_prefixes[j]); } os::free(new_prefixes); return JVMTI_ERROR_OUT_OF_MEMORY; } new_prefixes[i] = prefix; } _native_method_prefix_count = prefix_count; _native_method_prefixes = new_prefixes; } // now that we know the new prefixes have been successfully installed we can // safely remove the old ones if (old_prefix_count != 0) { for (int i = 0; i < old_prefix_count; i++) { os::free(old_prefixes[i]); } os::free(old_prefixes); } return JVMTI_ERROR_NONE; } // Collect all the prefixes which have been set in any JVM TI environments // by the SetNativeMethodPrefix(es) functions. Be sure to maintain the // order of environments and the order of prefixes within each environment. // Return in a resource allocated array. char** JvmtiEnvBase::get_all_native_method_prefixes(int* count_ptr) { assert(Threads::number_of_threads() == 0 || SafepointSynchronize::is_at_safepoint() || JvmtiThreadState_lock->is_locked(), "sanity check"); int total_count = 0; GrowableArray* prefix_array =new GrowableArray(5); JvmtiEnvIterator it; for (JvmtiEnvBase* env = it.first(); env != NULL; env = it.next(env)) { int prefix_count = env->get_native_method_prefix_count(); char** prefixes = env->get_native_method_prefixes(); for (int j = 0; j < prefix_count; j++) { // retrieve a prefix and so that it is safe against asynchronous changes // copy it into the resource area char* prefix = prefixes[j]; char* prefix_copy = NEW_RESOURCE_ARRAY(char, strlen(prefix)+1); strcpy(prefix_copy, prefix); prefix_array->at_put_grow(total_count++, prefix_copy); } } char** all_prefixes = NEW_RESOURCE_ARRAY(char*, total_count); char** p = all_prefixes; for (int i = 0; i < total_count; ++i) { *p++ = prefix_array->at(i); } *count_ptr = total_count; return all_prefixes; } void JvmtiEnvBase::set_event_callbacks(const jvmtiEventCallbacks* callbacks, jint size_of_callbacks) { assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check"); size_t byte_cnt = sizeof(jvmtiEventCallbacks); // clear in either case to be sure we got any gap between sizes memset(&_event_callbacks, 0, byte_cnt); // Now that JvmtiThreadState_lock is held, prevent a possible race condition where events // are re-enabled by a call to set event callbacks where the DisposeEnvironment // occurs after the boiler-plate environment check and before the lock is acquired. if (callbacks != NULL && is_valid()) { if (size_of_callbacks < (jint)byte_cnt) { byte_cnt = size_of_callbacks; } memcpy(&_event_callbacks, callbacks, byte_cnt); } } // Called from JVMTI entry points which perform stack walking. If the // associated JavaThread is the current thread, then wait_for_suspend // is not used. Otherwise, it determines if we should wait for the // "other" thread to complete external suspension. (NOTE: in future // releases the suspension mechanism should be reimplemented so this // is not necessary.) // bool JvmtiEnvBase::is_thread_fully_suspended(JavaThread* thr, bool wait_for_suspend, uint32_t *bits) { // "other" threads require special handling if (thr != JavaThread::current()) { if (wait_for_suspend) { // We are allowed to wait for the external suspend to complete // so give the other thread a chance to get suspended. if (!thr->wait_for_ext_suspend_completion(SuspendRetryCount, SuspendRetryDelay, bits)) { // didn't make it so let the caller know return false; } } // We aren't allowed to wait for the external suspend to complete // so if the other thread isn't externally suspended we need to // let the caller know. else if (!thr->is_ext_suspend_completed_with_lock(bits)) { return false; } } return true; } // In the fullness of time, all users of the method should instead // directly use allocate, besides being cleaner and faster, this will // mean much better out of memory handling unsigned char * JvmtiEnvBase::jvmtiMalloc(jlong size) { unsigned char* mem; jvmtiError result = allocate(size, &mem); assert(result == JVMTI_ERROR_NONE, "Allocate failed"); return mem; } // // Threads // jobject * JvmtiEnvBase::new_jobjectArray(int length, Handle *handles) { if (length == 0) { return NULL; } jobject *objArray = (jobject *) jvmtiMalloc(sizeof(jobject) * length); NULL_CHECK(objArray, NULL); for (int i=0; iis_a(SystemDictionary::Thread_klass())) { return NULL; } // The following returns NULL if the thread has not yet run or is in // process of exiting return java_lang_Thread::thread(t); } // update the access_flags for the field in the klass void JvmtiEnvBase::update_klass_field_access_flag(fieldDescriptor *fd) { instanceKlass* ik = instanceKlass::cast(fd->field_holder()); typeArrayOop fields = ik->fields(); fields->ushort_at_put(fd->index(), (jushort)fd->access_flags().as_short()); } // return the vframe on the specified thread and depth, NULL if no such frame vframe* JvmtiEnvBase::vframeFor(JavaThread* java_thread, jint depth) { if (!java_thread->has_last_Java_frame()) { return NULL; } RegisterMap reg_map(java_thread); vframe *vf = java_thread->last_java_vframe(®_map); int d = 0; while ((vf != NULL) && (d < depth)) { vf = vf->java_sender(); d++; } return vf; } // // utilities: JNI objects // jclass JvmtiEnvBase::get_jni_class_non_null(klassOop k) { assert(k != NULL, "k != NULL"); return (jclass)jni_reference(Klass::cast(k)->java_mirror()); } #ifndef JVMTI_KERNEL // // Field Information // bool JvmtiEnvBase::get_field_descriptor(klassOop k, jfieldID field, fieldDescriptor* fd) { if (!jfieldIDWorkaround::is_valid_jfieldID(k, field)) { return false; } bool found = false; if (jfieldIDWorkaround::is_static_jfieldID(field)) { JNIid* id = jfieldIDWorkaround::from_static_jfieldID(field); int offset = id->offset(); klassOop holder = id->holder(); found = instanceKlass::cast(holder)->find_local_field_from_offset(offset, true, fd); } else { // Non-static field. The fieldID is really the offset of the field within the object. int offset = jfieldIDWorkaround::from_instance_jfieldID(k, field); found = instanceKlass::cast(k)->find_field_from_offset(offset, false, fd); } return found; } // // Object Monitor Information // // // Count the number of objects for a lightweight monitor. The hobj // parameter is object that owns the monitor so this routine will // count the number of times the same object was locked by frames // in java_thread. // jint JvmtiEnvBase::count_locked_objects(JavaThread *java_thread, Handle hobj) { jint ret = 0; if (!java_thread->has_last_Java_frame()) { return ret; // no Java frames so no monitors } ResourceMark rm; HandleMark hm; RegisterMap reg_map(java_thread); for(javaVFrame *jvf=java_thread->last_java_vframe(®_map); jvf != NULL; jvf = jvf->java_sender()) { GrowableArray* mons = jvf->monitors(); if (!mons->is_empty()) { for (int i = 0; i < mons->length(); i++) { MonitorInfo *mi = mons->at(i); if (mi->owner_is_scalar_replaced()) continue; // see if owner of the monitor is our object if (mi->owner() != NULL && mi->owner() == hobj()) { ret++; } } } } return ret; } jvmtiError JvmtiEnvBase::get_current_contended_monitor(JavaThread *calling_thread, JavaThread *java_thread, jobject *monitor_ptr) { #ifdef ASSERT uint32_t debug_bits = 0; #endif assert((SafepointSynchronize::is_at_safepoint() || is_thread_fully_suspended(java_thread, false, &debug_bits)), "at safepoint or target thread is suspended"); oop obj = NULL; ObjectMonitor *mon = java_thread->current_waiting_monitor(); if (mon == NULL) { // thread is not doing an Object.wait() call mon = java_thread->current_pending_monitor(); if (mon != NULL) { // The thread is trying to enter() or raw_enter() an ObjectMonitor. obj = (oop)mon->object(); // If obj == NULL, then ObjectMonitor is raw which doesn't count // as contended for this API } // implied else: no contended ObjectMonitor } else { // thread is doing an Object.wait() call obj = (oop)mon->object(); assert(obj != NULL, "Object.wait() should have an object"); } if (obj == NULL) { *monitor_ptr = NULL; } else { HandleMark hm; Handle hobj(obj); *monitor_ptr = jni_reference(calling_thread, hobj); } return JVMTI_ERROR_NONE; } jvmtiError JvmtiEnvBase::get_owned_monitors(JavaThread *calling_thread, JavaThread* java_thread, GrowableArray *owned_monitors_list) { jvmtiError err = JVMTI_ERROR_NONE; #ifdef ASSERT uint32_t debug_bits = 0; #endif assert((SafepointSynchronize::is_at_safepoint() || is_thread_fully_suspended(java_thread, false, &debug_bits)), "at safepoint or target thread is suspended"); if (java_thread->has_last_Java_frame()) { ResourceMark rm; HandleMark hm; RegisterMap reg_map(java_thread); int depth = 0; for (javaVFrame *jvf = java_thread->last_java_vframe(®_map); jvf != NULL; jvf = jvf->java_sender()) { if (depth++ < MaxJavaStackTraceDepth) { // check for stack too deep // add locked objects for this frame into list err = get_locked_objects_in_frame(calling_thread, java_thread, jvf, owned_monitors_list, depth-1); if (err != JVMTI_ERROR_NONE) { return err; } } } } // Get off stack monitors. (e.g. acquired via jni MonitorEnter). JvmtiMonitorClosure jmc(java_thread, calling_thread, owned_monitors_list, this); ObjectSynchronizer::monitors_iterate(&jmc); err = jmc.error(); return err; } // Save JNI local handles for any objects that this frame owns. jvmtiError JvmtiEnvBase::get_locked_objects_in_frame(JavaThread* calling_thread, JavaThread* java_thread, javaVFrame *jvf, GrowableArray* owned_monitors_list, int stack_depth) { jvmtiError err = JVMTI_ERROR_NONE; ResourceMark rm; GrowableArray* mons = jvf->monitors(); if (mons->is_empty()) { return err; // this javaVFrame holds no monitors } HandleMark hm; oop wait_obj = NULL; { // save object of current wait() call (if any) for later comparison ObjectMonitor *mon = java_thread->current_waiting_monitor(); if (mon != NULL) { wait_obj = (oop)mon->object(); } } oop pending_obj = NULL; { // save object of current enter() call (if any) for later comparison ObjectMonitor *mon = java_thread->current_pending_monitor(); if (mon != NULL) { pending_obj = (oop)mon->object(); } } for (int i = 0; i < mons->length(); i++) { MonitorInfo *mi = mons->at(i); if (mi->owner_is_scalar_replaced()) continue; oop obj = mi->owner(); if (obj == NULL) { // this monitor doesn't have an owning object so skip it continue; } if (wait_obj == obj) { // the thread is waiting on this monitor so it isn't really owned continue; } if (pending_obj == obj) { // the thread is pending on this monitor so it isn't really owned continue; } if (owned_monitors_list->length() > 0) { // Our list has at least one object on it so we have to check // for recursive object locking bool found = false; for (int j = 0; j < owned_monitors_list->length(); j++) { jobject jobj = ((jvmtiMonitorStackDepthInfo*)owned_monitors_list->at(j))->monitor; oop check = JNIHandles::resolve(jobj); if (check == obj) { found = true; // we found the object break; } } if (found) { // already have this object so don't include it continue; } } // add the owning object to our list jvmtiMonitorStackDepthInfo *jmsdi; err = allocate(sizeof(jvmtiMonitorStackDepthInfo), (unsigned char **)&jmsdi); if (err != JVMTI_ERROR_NONE) { return err; } Handle hobj(obj); jmsdi->monitor = jni_reference(calling_thread, hobj); jmsdi->stack_depth = stack_depth; owned_monitors_list->append(jmsdi); } return err; } jvmtiError JvmtiEnvBase::get_stack_trace(JavaThread *java_thread, jint start_depth, jint max_count, jvmtiFrameInfo* frame_buffer, jint* count_ptr) { #ifdef ASSERT uint32_t debug_bits = 0; #endif assert((SafepointSynchronize::is_at_safepoint() || is_thread_fully_suspended(java_thread, false, &debug_bits)), "at safepoint or target thread is suspended"); int count = 0; if (java_thread->has_last_Java_frame()) { RegisterMap reg_map(java_thread); Thread* current_thread = Thread::current(); ResourceMark rm(current_thread); javaVFrame *jvf = java_thread->last_java_vframe(®_map); HandleMark hm(current_thread); if (start_depth != 0) { if (start_depth > 0) { for (int j = 0; j < start_depth && jvf != NULL; j++) { jvf = jvf->java_sender(); } if (jvf == NULL) { // start_depth is deeper than the stack depth return JVMTI_ERROR_ILLEGAL_ARGUMENT; } } else { // start_depth < 0 // we are referencing the starting depth based on the oldest // part of the stack. // optimize to limit the number of times that java_sender() is called javaVFrame *jvf_cursor = jvf; javaVFrame *jvf_prev = NULL; javaVFrame *jvf_prev_prev; int j = 0; while (jvf_cursor != NULL) { jvf_prev_prev = jvf_prev; jvf_prev = jvf_cursor; for (j = 0; j > start_depth && jvf_cursor != NULL; j--) { jvf_cursor = jvf_cursor->java_sender(); } } if (j == start_depth) { // previous pointer is exactly where we want to start jvf = jvf_prev; } else { // we need to back up further to get to the right place if (jvf_prev_prev == NULL) { // the -start_depth is greater than the stack depth return JVMTI_ERROR_ILLEGAL_ARGUMENT; } // j now is the number of frames on the stack starting with // jvf_prev, we start from jvf_prev_prev and move older on // the stack that many, the result is -start_depth frames // remaining. jvf = jvf_prev_prev; for (; j < 0; j++) { jvf = jvf->java_sender(); } } } } for (; count < max_count && jvf != NULL; count++) { frame_buffer[count].method = jvf->method()->jmethod_id(); frame_buffer[count].location = (jvf->method()->is_native() ? -1 : jvf->bci()); jvf = jvf->java_sender(); } } else { if (start_depth != 0) { // no frames and there is a starting depth return JVMTI_ERROR_ILLEGAL_ARGUMENT; } } *count_ptr = count; return JVMTI_ERROR_NONE; } jvmtiError JvmtiEnvBase::get_frame_count(JvmtiThreadState *state, jint *count_ptr) { assert((state != NULL), "JavaThread should create JvmtiThreadState before calling this method"); *count_ptr = state->count_frames(); return JVMTI_ERROR_NONE; } jvmtiError JvmtiEnvBase::get_frame_location(JavaThread *java_thread, jint depth, jmethodID* method_ptr, jlocation* location_ptr) { #ifdef ASSERT uint32_t debug_bits = 0; #endif assert((SafepointSynchronize::is_at_safepoint() || is_thread_fully_suspended(java_thread, false, &debug_bits)), "at safepoint or target thread is suspended"); Thread* current_thread = Thread::current(); ResourceMark rm(current_thread); vframe *vf = vframeFor(java_thread, depth); if (vf == NULL) { return JVMTI_ERROR_NO_MORE_FRAMES; } // vframeFor should return a java frame. If it doesn't // it means we've got an internal error and we return the // error in product mode. In debug mode we will instead // attempt to cast the vframe to a javaVFrame and will // cause an assertion/crash to allow further diagnosis. #ifdef PRODUCT if (!vf->is_java_frame()) { return JVMTI_ERROR_INTERNAL; } #endif HandleMark hm(current_thread); javaVFrame *jvf = javaVFrame::cast(vf); methodOop method = jvf->method(); if (method->is_native()) { *location_ptr = -1; } else { *location_ptr = jvf->bci(); } *method_ptr = method->jmethod_id(); return JVMTI_ERROR_NONE; } jvmtiError JvmtiEnvBase::get_object_monitor_usage(JavaThread* calling_thread, jobject object, jvmtiMonitorUsage* info_ptr) { HandleMark hm; Handle hobj; bool at_safepoint = SafepointSynchronize::is_at_safepoint(); // Check arguments { oop mirror = JNIHandles::resolve_external_guard(object); NULL_CHECK(mirror, JVMTI_ERROR_INVALID_OBJECT); NULL_CHECK(info_ptr, JVMTI_ERROR_NULL_POINTER); hobj = Handle(mirror); } JavaThread *owning_thread = NULL; ObjectMonitor *mon = NULL; jvmtiMonitorUsage ret = { NULL, 0, 0, NULL, 0, NULL }; uint32_t debug_bits = 0; // first derive the object's owner and entry_count (if any) { // Revoke any biases before querying the mark word if (SafepointSynchronize::is_at_safepoint()) { BiasedLocking::revoke_at_safepoint(hobj); } else { BiasedLocking::revoke_and_rebias(hobj, false, calling_thread); } address owner = NULL; { markOop mark = hobj()->mark(); if (!mark->has_monitor()) { // this object has a lightweight monitor if (mark->has_locker()) { owner = (address)mark->locker(); // save the address of the Lock word } // implied else: no owner } else { // this object has a heavyweight monitor mon = mark->monitor(); // The owner field of a heavyweight monitor may be NULL for no // owner, a JavaThread * or it may still be the address of the // Lock word in a JavaThread's stack. A monitor can be inflated // by a non-owning JavaThread, but only the owning JavaThread // can change the owner field from the Lock word to the // JavaThread * and it may not have done that yet. owner = (address)mon->owner(); } } if (owner != NULL) { // This monitor is owned so we have to find the owning JavaThread. // Since owning_thread_from_monitor_owner() grabs a lock, GC can // move our object at this point. However, our owner value is safe // since it is either the Lock word on a stack or a JavaThread *. owning_thread = Threads::owning_thread_from_monitor_owner(owner, !at_safepoint); assert(owning_thread != NULL, "sanity check"); if (owning_thread != NULL) { // robustness // The monitor's owner either has to be the current thread, at safepoint // or it has to be suspended. Any of these conditions will prevent both // contending and waiting threads from modifying the state of // the monitor. if (!at_safepoint && !JvmtiEnv::is_thread_fully_suspended(owning_thread, true, &debug_bits)) { return JVMTI_ERROR_THREAD_NOT_SUSPENDED; } HandleMark hm; Handle th(owning_thread->threadObj()); ret.owner = (jthread)jni_reference(calling_thread, th); } // implied else: no owner } if (owning_thread != NULL) { // monitor is owned if ((address)owning_thread == owner) { // the owner field is the JavaThread * assert(mon != NULL, "must have heavyweight monitor with JavaThread * owner"); ret.entry_count = mon->recursions() + 1; } else { // The owner field is the Lock word on the JavaThread's stack // so the recursions field is not valid. We have to count the // number of recursive monitor entries the hard way. We pass // a handle to survive any GCs along the way. ResourceMark rm; ret.entry_count = count_locked_objects(owning_thread, hobj); } } // implied else: entry_count == 0 } int nWant,nWait; if (mon != NULL) { // this object has a heavyweight monitor nWant = mon->contentions(); // # of threads contending for monitor nWait = mon->waiters(); // # of threads in Object.wait() ret.waiter_count = nWant + nWait; ret.notify_waiter_count = nWait; } else { // this object has a lightweight monitor ret.waiter_count = 0; ret.notify_waiter_count = 0; } // Allocate memory for heavyweight and lightweight monitor. jvmtiError err; err = allocate(ret.waiter_count * sizeof(jthread *), (unsigned char**)&ret.waiters); if (err != JVMTI_ERROR_NONE) { return err; } err = allocate(ret.notify_waiter_count * sizeof(jthread *), (unsigned char**)&ret.notify_waiters); if (err != JVMTI_ERROR_NONE) { deallocate((unsigned char*)ret.waiters); return err; } // now derive the rest of the fields if (mon != NULL) { // this object has a heavyweight monitor // Number of waiters may actually be less than the waiter count. // So NULL out memory so that unused memory will be NULL. memset(ret.waiters, 0, ret.waiter_count * sizeof(jthread *)); memset(ret.notify_waiters, 0, ret.notify_waiter_count * sizeof(jthread *)); if (ret.waiter_count > 0) { // we have contending and/or waiting threads HandleMark hm; if (nWant > 0) { // we have contending threads ResourceMark rm; // get_pending_threads returns only java thread so we do not need to // check for non java threads. GrowableArray* wantList = Threads::get_pending_threads( nWant, (address)mon, !at_safepoint); if (wantList->length() < nWant) { // robustness: the pending list has gotten smaller nWant = wantList->length(); } for (int i = 0; i < nWant; i++) { JavaThread *pending_thread = wantList->at(i); // If the monitor has no owner, then a non-suspended contending // thread could potentially change the state of the monitor by // entering it. The JVM/TI spec doesn't allow this. if (owning_thread == NULL && !at_safepoint & !JvmtiEnv::is_thread_fully_suspended(pending_thread, true, &debug_bits)) { if (ret.owner != NULL) { destroy_jni_reference(calling_thread, ret.owner); } for (int j = 0; j < i; j++) { destroy_jni_reference(calling_thread, ret.waiters[j]); } deallocate((unsigned char*)ret.waiters); deallocate((unsigned char*)ret.notify_waiters); return JVMTI_ERROR_THREAD_NOT_SUSPENDED; } Handle th(pending_thread->threadObj()); ret.waiters[i] = (jthread)jni_reference(calling_thread, th); } } if (nWait > 0) { // we have threads in Object.wait() int offset = nWant; // add after any contending threads ObjectWaiter *waiter = mon->first_waiter(); for (int i = 0, j = 0; i < nWait; i++) { if (waiter == NULL) { // robustness: the waiting list has gotten smaller nWait = j; break; } Thread *t = mon->thread_of_waiter(waiter); if (t != NULL && t->is_Java_thread()) { JavaThread *wjava_thread = (JavaThread *)t; // If the thread was found on the ObjectWaiter list, then // it has not been notified. This thread can't change the // state of the monitor so it doesn't need to be suspended. Handle th(wjava_thread->threadObj()); ret.waiters[offset + j] = (jthread)jni_reference(calling_thread, th); ret.notify_waiters[j++] = (jthread)jni_reference(calling_thread, th); } waiter = mon->next_waiter(waiter); } } } // Adjust count. nWant and nWait count values may be less than original. ret.waiter_count = nWant + nWait; ret.notify_waiter_count = nWait; } else { // this object has a lightweight monitor and we have nothing more // to do here because the defaults are just fine. } // we don't update return parameter unless everything worked *info_ptr = ret; return JVMTI_ERROR_NONE; } ResourceTracker::ResourceTracker(JvmtiEnv* env) { _env = env; _allocations = new (ResourceObj::C_HEAP) GrowableArray(20, true); _failed = false; } ResourceTracker::~ResourceTracker() { if (_failed) { for (int i=0; i<_allocations->length(); i++) { _env->deallocate(_allocations->at(i)); } } delete _allocations; } jvmtiError ResourceTracker::allocate(jlong size, unsigned char** mem_ptr) { unsigned char *ptr; jvmtiError err = _env->allocate(size, &ptr); if (err == JVMTI_ERROR_NONE) { _allocations->append(ptr); *mem_ptr = ptr; } else { *mem_ptr = NULL; _failed = true; } return err; } unsigned char* ResourceTracker::allocate(jlong size) { unsigned char* ptr; allocate(size, &ptr); return ptr; } char* ResourceTracker::strdup(const char* str) { char *dup_str = (char*)allocate(strlen(str)+1); if (dup_str != NULL) { strcpy(dup_str, str); } return dup_str; } struct StackInfoNode { struct StackInfoNode *next; jvmtiStackInfo info; }; // Create a jvmtiStackInfo inside a linked list node and create a // buffer for the frame information, both allocated as resource objects. // Fill in both the jvmtiStackInfo and the jvmtiFrameInfo. // Note that either or both of thr and thread_oop // may be null if the thread is new or has exited. void VM_GetMultipleStackTraces::fill_frames(jthread jt, JavaThread *thr, oop thread_oop) { assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint"); jint state = 0; struct StackInfoNode *node = NEW_RESOURCE_OBJ(struct StackInfoNode); jvmtiStackInfo *infop = &(node->info); node->next = head(); set_head(node); infop->frame_count = 0; infop->thread = jt; if (thread_oop != NULL) { // get most state bits state = (jint)java_lang_Thread::get_thread_status(thread_oop); } if (thr != NULL) { // add more state bits if there is a JavaThead to query // same as is_being_ext_suspended() but without locking if (thr->is_ext_suspended() || thr->is_external_suspend()) { state |= JVMTI_THREAD_STATE_SUSPENDED; } JavaThreadState jts = thr->thread_state(); if (jts == _thread_in_native) { state |= JVMTI_THREAD_STATE_IN_NATIVE; } OSThread* osThread = thr->osthread(); if (osThread != NULL && osThread->interrupted()) { state |= JVMTI_THREAD_STATE_INTERRUPTED; } } infop->state = state; if (thr != NULL || (state & JVMTI_THREAD_STATE_ALIVE) != 0) { infop->frame_buffer = NEW_RESOURCE_ARRAY(jvmtiFrameInfo, max_frame_count()); env()->get_stack_trace(thr, 0, max_frame_count(), infop->frame_buffer, &(infop->frame_count)); } else { infop->frame_buffer = NULL; infop->frame_count = 0; } _frame_count_total += infop->frame_count; } // Based on the stack information in the linked list, allocate memory // block to return and fill it from the info in the linked list. void VM_GetMultipleStackTraces::allocate_and_fill_stacks(jint thread_count) { // do I need to worry about alignment issues? jlong alloc_size = thread_count * sizeof(jvmtiStackInfo) + _frame_count_total * sizeof(jvmtiFrameInfo); env()->allocate(alloc_size, (unsigned char **)&_stack_info); // pointers to move through the newly allocated space as it is filled in jvmtiStackInfo *si = _stack_info + thread_count; // bottom of stack info jvmtiFrameInfo *fi = (jvmtiFrameInfo *)si; // is the top of frame info // copy information in resource area into allocated buffer // insert stack info backwards since linked list is backwards // insert frame info forwards // walk the StackInfoNodes for (struct StackInfoNode *sin = head(); sin != NULL; sin = sin->next) { jint frame_count = sin->info.frame_count; size_t frames_size = frame_count * sizeof(jvmtiFrameInfo); --si; memcpy(si, &(sin->info), sizeof(jvmtiStackInfo)); if (frames_size == 0) { si->frame_buffer = NULL; } else { memcpy(fi, sin->info.frame_buffer, frames_size); si->frame_buffer = fi; // point to the new allocated copy of the frames fi += frame_count; } } assert(si == _stack_info, "the last copied stack info must be the first record"); assert((unsigned char *)fi == ((unsigned char *)_stack_info) + alloc_size, "the last copied frame info must be the last record"); } void VM_GetThreadListStackTraces::doit() { assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint"); ResourceMark rm; for (int i = 0; i < _thread_count; ++i) { jthread jt = _thread_list[i]; oop thread_oop = JNIHandles::resolve_external_guard(jt); if (thread_oop == NULL || !thread_oop->is_a(SystemDictionary::Thread_klass())) { set_result(JVMTI_ERROR_INVALID_THREAD); return; } fill_frames(jt, java_lang_Thread::thread(thread_oop), thread_oop); } allocate_and_fill_stacks(_thread_count); } void VM_GetAllStackTraces::doit() { assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint"); ResourceMark rm; _final_thread_count = 0; for (JavaThread *jt = Threads::first(); jt != NULL; jt = jt->next()) { oop thread_oop = jt->threadObj(); if (thread_oop != NULL && !jt->is_exiting() && java_lang_Thread::is_alive(thread_oop) && !jt->is_hidden_from_external_view()) { ++_final_thread_count; // Handle block of the calling thread is used to create local refs. fill_frames((jthread)JNIHandles::make_local(_calling_thread, thread_oop), jt, thread_oop); } } allocate_and_fill_stacks(_final_thread_count); } // Verifies that the top frame is a java frame in an expected state. // Deoptimizes frame if needed. // Checks that the frame method signature matches the return type (tos). // HandleMark must be defined in the caller only. // It is to keep a ret_ob_h handle alive after return to the caller. jvmtiError JvmtiEnvBase::check_top_frame(JavaThread* current_thread, JavaThread* java_thread, jvalue value, TosState tos, Handle* ret_ob_h) { ResourceMark rm(current_thread); vframe *vf = vframeFor(java_thread, 0); NULL_CHECK(vf, JVMTI_ERROR_NO_MORE_FRAMES); javaVFrame *jvf = (javaVFrame*) vf; if (!vf->is_java_frame() || jvf->method()->is_native()) { return JVMTI_ERROR_OPAQUE_FRAME; } // If the frame is a compiled one, need to deoptimize it. if (vf->is_compiled_frame()) { if (!vf->fr().can_be_deoptimized()) { return JVMTI_ERROR_OPAQUE_FRAME; } Deoptimization::deoptimize_frame(java_thread, jvf->fr().id()); } // Get information about method return type symbolHandle signature(current_thread, jvf->method()->signature()); ResultTypeFinder rtf(signature); TosState fr_tos = as_TosState(rtf.type()); if (fr_tos != tos) { if (tos != itos || (fr_tos != btos && fr_tos != ctos && fr_tos != stos)) { return JVMTI_ERROR_TYPE_MISMATCH; } } // Check that the jobject class matches the return type signature. jobject jobj = value.l; if (tos == atos && jobj != NULL) { // NULL reference is allowed Handle ob_h = Handle(current_thread, JNIHandles::resolve_external_guard(jobj)); NULL_CHECK(ob_h, JVMTI_ERROR_INVALID_OBJECT); KlassHandle ob_kh = KlassHandle(current_thread, ob_h()->klass()); NULL_CHECK(ob_kh, JVMTI_ERROR_INVALID_OBJECT); // Method return type signature. char* ty_sign = 1 + strchr(signature->as_C_string(), ')'); if (!VM_GetOrSetLocal::is_assignable(ty_sign, Klass::cast(ob_kh()), current_thread)) { return JVMTI_ERROR_TYPE_MISMATCH; } *ret_ob_h = ob_h; } return JVMTI_ERROR_NONE; } /* end check_top_frame */ // ForceEarlyReturn follows the PopFrame approach in many aspects. // Main difference is on the last stage in the interpreter. // The PopFrame stops method execution to continue execution // from the same method call instruction. // The ForceEarlyReturn forces return from method so the execution // continues at the bytecode following the method call. // Threads_lock NOT held, java_thread not protected by lock // java_thread - pre-checked jvmtiError JvmtiEnvBase::force_early_return(JavaThread* java_thread, jvalue value, TosState tos) { JavaThread* current_thread = JavaThread::current(); HandleMark hm(current_thread); uint32_t debug_bits = 0; // retrieve or create the state JvmtiThreadState* state = JvmtiThreadState::state_for(java_thread); if (state == NULL) { return JVMTI_ERROR_THREAD_NOT_ALIVE; } // Check if java_thread is fully suspended if (!is_thread_fully_suspended(java_thread, true /* wait for suspend completion */, &debug_bits)) { return JVMTI_ERROR_THREAD_NOT_SUSPENDED; } // Check to see if a ForceEarlyReturn was already in progress if (state->is_earlyret_pending()) { // Probably possible for JVMTI clients to trigger this, but the // JPDA backend shouldn't allow this to happen return JVMTI_ERROR_INTERNAL; } { // The same as for PopFrame. Workaround bug: // 4812902: popFrame hangs if the method is waiting at a synchronize // Catch this condition and return an error to avoid hanging. // Now JVMTI spec allows an implementation to bail out with an opaque // frame error. OSThread* osThread = java_thread->osthread(); if (osThread->get_state() == MONITOR_WAIT) { return JVMTI_ERROR_OPAQUE_FRAME; } } Handle ret_ob_h = Handle(); jvmtiError err = check_top_frame(current_thread, java_thread, value, tos, &ret_ob_h); if (err != JVMTI_ERROR_NONE) { return err; } assert(tos != atos || value.l == NULL || ret_ob_h() != NULL, "return object oop must not be NULL if jobject is not NULL"); // Update the thread state to reflect that the top frame must be // forced to return. // The current frame will be returned later when the suspended // thread is resumed and right before returning from VM to Java. // (see call_VM_base() in assembler_.cpp). state->set_earlyret_pending(); state->set_earlyret_oop(ret_ob_h()); state->set_earlyret_value(value, tos); // Set pending step flag for this early return. // It is cleared when next step event is posted. state->set_pending_step_for_earlyret(); return JVMTI_ERROR_NONE; } /* end force_early_return */ void JvmtiMonitorClosure::do_monitor(ObjectMonitor* mon) { if ( _error != JVMTI_ERROR_NONE) { // Error occurred in previous iteration so no need to add // to the list. return; } if (mon->owner() == _java_thread ) { // Filter out on stack monitors collected during stack walk. oop obj = (oop)mon->object(); bool found = false; for (int j = 0; j < _owned_monitors_list->length(); j++) { jobject jobj = ((jvmtiMonitorStackDepthInfo*)_owned_monitors_list->at(j))->monitor; oop check = JNIHandles::resolve(jobj); if (check == obj) { // On stack monitor already collected during the stack walk. found = true; break; } } if (found == false) { // This is off stack monitor (e.g. acquired via jni MonitorEnter). jvmtiError err; jvmtiMonitorStackDepthInfo *jmsdi; err = _env->allocate(sizeof(jvmtiMonitorStackDepthInfo), (unsigned char **)&jmsdi); if (err != JVMTI_ERROR_NONE) { _error = err; return; } Handle hobj(obj); jmsdi->monitor = _env->jni_reference(_calling_thread, hobj); // stack depth is unknown for this monitor. jmsdi->stack_depth = -1; _owned_monitors_list->append(jmsdi); } } } #endif // !JVMTI_KERNEL