ART: Add JNI function table manipulation
Add support for a function table override. This will override the
decision between the regular and the CheckJNI function tables, if
set.
Bug: 34343708
Test: m test-art-host-gtest-jni_internal_test
Change-Id: I0e95b0cbd21f4efdcd8c3d312781d9aeeff54a1e
diff --git a/runtime/base/mutex.cc b/runtime/base/mutex.cc
index 9116097..e05a85a 100644
--- a/runtime/base/mutex.cc
+++ b/runtime/base/mutex.cc
@@ -46,6 +46,7 @@
ReaderWriterMutex* Locks::heap_bitmap_lock_ = nullptr;
Mutex* Locks::instrument_entrypoints_lock_ = nullptr;
Mutex* Locks::intern_table_lock_ = nullptr;
+Mutex* Locks::jni_function_table_lock_ = nullptr;
Mutex* Locks::jni_libraries_lock_ = nullptr;
Mutex* Locks::logging_lock_ = nullptr;
Mutex* Locks::mem_maps_lock_ = nullptr;
@@ -957,6 +958,7 @@
DCHECK(verifier_deps_lock_ != nullptr);
DCHECK(host_dlopen_handles_lock_ != nullptr);
DCHECK(intern_table_lock_ != nullptr);
+ DCHECK(jni_function_table_lock_ != nullptr);
DCHECK(jni_libraries_lock_ != nullptr);
DCHECK(logging_lock_ != nullptr);
DCHECK(mutator_lock_ != nullptr);
@@ -1098,6 +1100,10 @@
DCHECK(jni_weak_globals_lock_ == nullptr);
jni_weak_globals_lock_ = new Mutex("JNI weak global reference table lock", current_lock_level);
+ UPDATE_CURRENT_LOCK_LEVEL(kJniFunctionTableLock);
+ DCHECK(jni_function_table_lock_ == nullptr);
+ jni_function_table_lock_ = new Mutex("JNI function table lock", current_lock_level);
+
UPDATE_CURRENT_LOCK_LEVEL(kAbortLock);
DCHECK(abort_lock_ == nullptr);
abort_lock_ = new Mutex("abort lock", current_lock_level, true);
diff --git a/runtime/base/mutex.h b/runtime/base/mutex.h
index 2adeb8c..21dd437 100644
--- a/runtime/base/mutex.h
+++ b/runtime/base/mutex.h
@@ -68,6 +68,7 @@
kRosAllocBulkFreeLock,
kMarkSweepMarkStackLock,
kTransactionLogLock,
+ kJniFunctionTableLock,
kJniWeakGlobalsLock,
kJniGlobalsLock,
kReferenceQueueSoftReferencesLock,
@@ -698,8 +699,11 @@
// Guard accesses to the JNI Weak Global Reference table.
static Mutex* jni_weak_globals_lock_ ACQUIRED_AFTER(jni_globals_lock_);
+ // Guard accesses to the JNI function table override.
+ static Mutex* jni_function_table_lock_ ACQUIRED_AFTER(jni_weak_globals_lock_);
+
// Have an exclusive aborting thread.
- static Mutex* abort_lock_ ACQUIRED_AFTER(jni_weak_globals_lock_);
+ static Mutex* abort_lock_ ACQUIRED_AFTER(jni_function_table_lock_);
// Allow mutual exclusion when manipulating Thread::suspend_count_.
// TODO: Does the trade-off of a per-thread lock make sense?
diff --git a/runtime/jni_env_ext.cc b/runtime/jni_env_ext.cc
index 5a3fafa..0148a1c 100644
--- a/runtime/jni_env_ext.cc
+++ b/runtime/jni_env_ext.cc
@@ -29,6 +29,7 @@
#include "mirror/object-inl.h"
#include "nth_caller_visitor.h"
#include "thread-inl.h"
+#include "thread_list.h"
namespace art {
@@ -37,6 +38,8 @@
static constexpr size_t kMonitorsInitial = 32; // Arbitrary.
static constexpr size_t kMonitorsMax = 4096; // Arbitrary sanity check.
+const JNINativeInterface* JNIEnvExt::table_override_ = nullptr;
+
// Checking "locals" requires the mutator lock, but at creation time we're really only interested
// in validity, which isn't changing. To avoid grabbing the mutator lock, factored out and tagged
// with NO_THREAD_SAFETY_ANALYSIS.
@@ -78,10 +81,10 @@
runtime_deleted(false),
critical(0),
monitors("monitors", kMonitorsInitial, kMonitorsMax) {
- functions = unchecked_functions = GetJniNativeInterface();
- if (vm->IsCheckJniEnabled()) {
- SetCheckJniEnabled(true);
- }
+ MutexLock mu(Thread::Current(), *Locks::jni_function_table_lock_);
+ check_jni = vm->IsCheckJniEnabled();
+ functions = GetFunctionTable(check_jni);
+ unchecked_functions = GetJniNativeInterface();
}
void JNIEnvExt::SetFunctionsToRuntimeShutdownFunctions() {
@@ -107,7 +110,12 @@
void JNIEnvExt::SetCheckJniEnabled(bool enabled) {
check_jni = enabled;
- functions = enabled ? GetCheckJniNativeInterface() : GetJniNativeInterface();
+ MutexLock mu(Thread::Current(), *Locks::jni_function_table_lock_);
+ functions = GetFunctionTable(enabled);
+ // Check whether this is a no-op because of override.
+ if (enabled && JNIEnvExt::table_override_ != nullptr) {
+ LOG(WARNING) << "Enabling CheckJNI after a JNIEnv function table override is not functional.";
+ }
}
void JNIEnvExt::DumpReferenceTables(std::ostream& os) {
@@ -269,4 +277,33 @@
}
}
+static void ThreadResetFunctionTable(Thread* thread, void* arg ATTRIBUTE_UNUSED)
+ REQUIRES(Locks::jni_function_table_lock_) {
+ JNIEnvExt* env = thread->GetJniEnv();
+ bool check_jni = env->check_jni;
+ env->functions = JNIEnvExt::GetFunctionTable(check_jni);
+}
+
+void JNIEnvExt::SetTableOverride(const JNINativeInterface* table_override) {
+ MutexLock mu(Thread::Current(), *Locks::thread_list_lock_);
+ MutexLock mu2(Thread::Current(), *Locks::jni_function_table_lock_);
+
+ JNIEnvExt::table_override_ = table_override;
+
+ // See if we have a runtime. Note: we cannot run other code (like JavaVMExt's CheckJNI install
+ // code), as we'd have to recursively lock the mutex.
+ Runtime* runtime = Runtime::Current();
+ if (runtime != nullptr) {
+ runtime->GetThreadList()->ForEach(ThreadResetFunctionTable, nullptr);
+ }
+}
+
+const JNINativeInterface* JNIEnvExt::GetFunctionTable(bool check_jni) {
+ const JNINativeInterface* override = JNIEnvExt::table_override_;
+ if (override != nullptr) {
+ return override;
+ }
+ return check_jni ? GetCheckJniNativeInterface() : GetJniNativeInterface();
+}
+
} // namespace art
diff --git a/runtime/jni_env_ext.h b/runtime/jni_env_ext.h
index 5cca0ae..4004c45 100644
--- a/runtime/jni_env_ext.h
+++ b/runtime/jni_env_ext.h
@@ -43,7 +43,7 @@
void DumpReferenceTables(std::ostream& os)
REQUIRES_SHARED(Locks::mutator_lock_);
- void SetCheckJniEnabled(bool enabled);
+ void SetCheckJniEnabled(bool enabled) REQUIRES(!Locks::jni_function_table_lock_);
void PushFrame(int capacity) REQUIRES_SHARED(Locks::mutator_lock_);
void PopFrame() REQUIRES_SHARED(Locks::mutator_lock_);
@@ -104,10 +104,27 @@
// Set the functions to the runtime shutdown functions.
void SetFunctionsToRuntimeShutdownFunctions();
+ // Set the function table override. This will install the override (or original table, if null)
+ // to all threads.
+ // Note: JNI function table overrides are sensitive to the order of operations wrt/ CheckJNI.
+ // After overriding the JNI function table, CheckJNI toggling is ignored.
+ static void SetTableOverride(const JNINativeInterface* table_override)
+ REQUIRES(!Locks::thread_list_lock_, !Locks::jni_function_table_lock_);
+
+ // Return either the regular, or the CheckJNI function table. Will return table_override_ instead
+ // if it is not null.
+ static const JNINativeInterface* GetFunctionTable(bool check_jni)
+ REQUIRES(Locks::jni_function_table_lock_);
+
private:
+ // Override of function tables. This applies to both default as well as instrumented (CheckJNI)
+ // function tables.
+ static const JNINativeInterface* table_override_ GUARDED_BY(Locks::jni_function_table_lock_);
+
// The constructor should not be called directly. It may leave the object in an erroneous state,
// and the result needs to be checked.
- JNIEnvExt(Thread* self, JavaVMExt* vm, std::string* error_msg);
+ JNIEnvExt(Thread* self, JavaVMExt* vm, std::string* error_msg)
+ REQUIRES(!Locks::jni_function_table_lock_);
// All locked objects, with the (Java caller) stack frame that locked them. Used in CheckJNI
// to ensure that only monitors locked in this native frame are being unlocked, and that at
diff --git a/runtime/jni_internal_test.cc b/runtime/jni_internal_test.cc
index 4da5e23..08d1eeb 100644
--- a/runtime/jni_internal_test.cc
+++ b/runtime/jni_internal_test.cc
@@ -2346,4 +2346,39 @@
EXPECT_EQ(segment_state_now, segment_state_computed);
}
+static size_t gGlobalRefCount = 0;
+static const JNINativeInterface* gOriginalEnv = nullptr;
+
+static jobject CountNewGlobalRef(JNIEnv* env, jobject o) {
+ ++gGlobalRefCount;
+ return gOriginalEnv->NewGlobalRef(env, o);
+}
+
+// Test the table override.
+TEST_F(JniInternalTest, JNIEnvExtTableOverride) {
+ JNINativeInterface env_override;
+ memcpy(&env_override, env_->functions, sizeof(JNINativeInterface));
+
+ gOriginalEnv = env_->functions;
+ env_override.NewGlobalRef = CountNewGlobalRef;
+ gGlobalRefCount = 0;
+
+ jclass local = env_->FindClass("java/lang/Object");
+ ASSERT_TRUE(local != nullptr);
+
+ // Set the table, add a global ref, see whether the counter increases.
+ JNIEnvExt::SetTableOverride(&env_override);
+
+ jobject global = env_->NewGlobalRef(local);
+ EXPECT_EQ(1u, gGlobalRefCount);
+ env_->DeleteGlobalRef(global);
+
+ // Reset
+ JNIEnvExt::SetTableOverride(nullptr);
+
+ jobject global2 = env_->NewGlobalRef(local);
+ EXPECT_EQ(1u, gGlobalRefCount);
+ env_->DeleteGlobalRef(global2);
+}
+
} // namespace art