--- a/src/hotspot/share/prims/nativeLookup.cpp Thu Oct 17 20:27:44 2019 +0100
+++ b/src/hotspot/share/prims/nativeLookup.cpp Thu Oct 17 20:53:35 2019 +0100
@@ -38,6 +38,7 @@
#include "prims/unsafe.hpp"
#include "runtime/arguments.hpp"
#include "runtime/handles.inline.hpp"
+#include "runtime/interfaceSupport.inline.hpp"
#include "runtime/javaCalls.hpp"
#include "runtime/os.inline.hpp"
#include "runtime/sharedRuntime.hpp"
@@ -138,7 +139,7 @@
#endif
};
-static address lookup_special_native(char* jni_name) {
+static address lookup_special_native(const char* jni_name) {
int count = sizeof(lookup_special_native_methods) / sizeof(JNINativeMethod);
for (int i = 0; i < count; i++) {
// NB: To ignore the jni prefix and jni postfix strstr is used matching.
@@ -151,13 +152,8 @@
address NativeLookup::lookup_style(const methodHandle& method, char* pure_name, const char* long_name, int args_size, bool os_style, bool& in_base_library, TRAPS) {
address entry;
- // Compute complete JNI name for style
- stringStream st;
- if (os_style) os::print_jni_name_prefix_on(&st, args_size);
- st.print_raw(pure_name);
- st.print_raw(long_name);
- if (os_style) os::print_jni_name_suffix_on(&st, args_size);
- char* jni_name = st.as_string();
+ const char* jni_name = compute_complete_jni_name(pure_name, long_name, args_size, os_style);
+
// If the loader is null we have a system class, so we attempt a lookup in
// the native Java library. This takes care of any bootstrapping problems.
@@ -205,40 +201,26 @@
return entry;
}
-
-address NativeLookup::lookup_critical_style(const methodHandle& method, char* pure_name, const char* long_name, int args_size, bool os_style) {
- if (!method->has_native_function()) {
- return NULL;
+const char* NativeLookup::compute_complete_jni_name(const char* pure_name, const char* long_name, int args_size, bool os_style) {
+ stringStream st;
+ if (os_style) {
+ os::print_jni_name_prefix_on(&st, args_size);
}
- address current_entry = method->native_function();
-
- char dll_name[JVM_MAXPATHLEN];
- int offset;
- if (os::dll_address_to_library_name(current_entry, dll_name, sizeof(dll_name), &offset)) {
- char ebuf[32];
- void* dll = os::dll_load(dll_name, ebuf, sizeof(ebuf));
- if (dll != NULL) {
- // Compute complete JNI name for style
- stringStream st;
- if (os_style) os::print_jni_name_prefix_on(&st, args_size);
- st.print_raw(pure_name);
- st.print_raw(long_name);
- if (os_style) os::print_jni_name_suffix_on(&st, args_size);
- char* jni_name = st.as_string();
- address critical_entry = (address)os::dll_lookup(dll, jni_name);
- // Close the handle to avoid keeping the library alive if the native method holder is unloaded.
- // This is fine because the library is still kept alive by JNI (see JVM_LoadLibrary). As soon
- // as the holder class and the library are unloaded (see JVM_UnloadLibrary), the native wrapper
- // that calls 'critical_entry' becomes unreachable and is unloaded as well.
- os::dll_unload(dll);
- return critical_entry;
- }
+ st.print_raw(pure_name);
+ st.print_raw(long_name);
+ if (os_style) {
+ os::print_jni_name_suffix_on(&st, args_size);
}
- return NULL;
+ return st.as_string();
}
+address NativeLookup::lookup_critical_style(void* dll, const char* pure_name, const char* long_name, int args_size, bool os_style) {
+ const char* jni_name = compute_complete_jni_name(pure_name, long_name, args_size, os_style);
+ assert(dll != NULL, "dll must be loaded");
+ return (address)os::dll_lookup(dll, jni_name);
+}
// Check all the formats of native implementation name to see if there is one
// for the specified method.
@@ -277,7 +259,7 @@
// Check all the formats of native implementation name to see if there is one
// for the specified method.
address NativeLookup::lookup_critical_entry(const methodHandle& method) {
- if (!CriticalJNINatives) return NULL;
+ assert(CriticalJNINatives, "or should not be here");
if (method->is_synchronized() ||
!method->is_static()) {
@@ -286,7 +268,6 @@
}
ResourceMark rm;
- address entry = NULL;
Symbol* signature = method->signature();
for (int end = 0; end < signature->utf8_length(); end++) {
@@ -296,9 +277,6 @@
}
}
- // Compute critical name
- char* critical_name = critical_jni_name(method);
-
// Compute argument size
int args_size = method->size_of_parameters();
for (SignatureStream ss(signature); !ss.at_return_type(); ss.next()) {
@@ -307,25 +285,66 @@
}
}
+ // dll handling requires I/O. Don't do that while in _thread_in_vm (safepoint may get requested).
+ ThreadToNativeFromVM thread_in_native(JavaThread::current());
+
+ void* dll = dll_load(method);
+ address entry = NULL;
+
+ if (dll != NULL) {
+ entry = lookup_critical_style(dll, method, args_size);
+ // Close the handle to avoid keeping the library alive if the native method holder is unloaded.
+ // This is fine because the library is still kept alive by JNI (see JVM_LoadLibrary). As soon
+ // as the holder class and the library are unloaded (see JVM_UnloadLibrary), the native wrapper
+ // that calls 'critical_entry' becomes unreachable and is unloaded as well.
+ os::dll_unload(dll);
+ }
+
+ return entry; // NULL indicates not found
+}
+
+void* NativeLookup::dll_load(const methodHandle& method) {
+ if (method->has_native_function()) {
+
+ address current_entry = method->native_function();
+
+ char dll_name[JVM_MAXPATHLEN];
+ int offset;
+ if (os::dll_address_to_library_name(current_entry, dll_name, sizeof(dll_name), &offset)) {
+ char ebuf[32];
+ return os::dll_load(dll_name, ebuf, sizeof(ebuf));
+ }
+ }
+
+ return NULL;
+}
+
+address NativeLookup::lookup_critical_style(void* dll, const methodHandle& method, int args_size) {
+ address entry = NULL;
+ const char* critical_name = critical_jni_name(method);
+
// 1) Try JNI short style
- entry = lookup_critical_style(method, critical_name, "", args_size, true);
- if (entry != NULL) return entry;
+ entry = lookup_critical_style(dll, critical_name, "", args_size, true);
+ if (entry != NULL) {
+ return entry;
+ }
- // Compute long name
- char* long_name = long_jni_name(method);
+ const char* long_name = long_jni_name(method);
// 2) Try JNI long style
- entry = lookup_critical_style(method, critical_name, long_name, args_size, true);
- if (entry != NULL) return entry;
+ entry = lookup_critical_style(dll, critical_name, long_name, args_size, true);
+ if (entry != NULL) {
+ return entry;
+ }
// 3) Try JNI short style without os prefix/suffix
- entry = lookup_critical_style(method, critical_name, "", args_size, false);
- if (entry != NULL) return entry;
+ entry = lookup_critical_style(dll, critical_name, "", args_size, false);
+ if (entry != NULL) {
+ return entry;
+ }
// 4) Try JNI long style without os prefix/suffix
- entry = lookup_critical_style(method, critical_name, long_name, args_size, false);
-
- return entry; // NULL indicates not found
+ return lookup_critical_style(dll, critical_name, long_name, args_size, false);
}
// Check if there are any JVM TI prefixes which have been applied to the native method name.