I am working on loading jvm.dll into go programm using cgo bindings on windows(GOOS=windows;GOARCH=amd64). JDK is installed and following is configured in PATH variable:
c:\Program Files\Java\jdk1.8.0_231\jre\bin\
%_ALT_JAVA_HOME_DIR% is set to "c:\Program Files\Java\jdk1.8.0_231\jre\"
C code below:
JVM *jvm;
jvm = malloc(sizeof(JVM));
JavaVMInitArgs vm_args;
vm_args.version=JNI_VERSION_1_8;
jint ret = JNI_CreateJavaVM(&jvm->jvm, (void **)&jvm->env, &vm_args);
}
is calling go code below
import "C"
import (
"syscall"
"unsafe"
)
var mod, _ = syscall.LoadLibrary("jvm.dll")
var createJvm, _ = syscall.GetProcAddress(mod, "JNI_CreateJavaVM")
var getDefaultArgs,_ = syscall.GetProcAddress(mod, "JNI_GetDefaultJavaVMInitArgs")
//export JNI_CreateJavaVM
func JNI_CreateJavaVM(jvm unsafe.Pointer, env unsafe.Pointer, args unsafe.Pointer) int32 {
println("jvm", jvm)
println("env", env)
println("args", args)
var resCode, _, err = syscall.Syscall(uintptr(getDefaultArgs), 1, uintptr(args),0,0);
println("result of JNI_GetDefaultJavaVMInitArgs", int32( resCode), err)
resCode, _, err = syscall.Syscall(uintptr(createJvm), 3, uintptr(jvm), uintptr(env), uintptr(args));
println("result of JNI_CreateJavaVM", int32( resCode), err)
return int32(resCode);
}
At second syscall code fails with following output:
env 0xe05de0
args 0x86fcf0
result of JNI_GetDefaultJavaVMInitArgs 0 0
Exception 0xc0000005 0x0 0x0 0x286503b6
PC=0x286503b6
signal arrived during external code execution
syscall.Syscall(0x6caae840, 0x3, 0xe05de8, 0xe05de0, 0x86fcf0, 0x0, 0x0, 0x0)
C:/Users/user/sdk/go1.14rc1/src/runtime/syscall_windows.go:188 +0xe9
test/jni.JNI_CreateJavaVM(0xe05de8, 0xe05de0, 0x86fcf0, 0x0)
C:/Users/user/IdeaProjects/test/jni/jni.go:21 +0x1c1
test/jni._cgoexpwrap_c7fe4a664520_JNI_CreateJavaVM(0xe05de8, 0xe05de0, 0x86fcf0, 0x7ffada619da0)
_cgo_gotypes.go:467 +0x46
test/jni._Cfunc_createJVM(0xe01a50, 0x6, 0x0)
_cgo_gotypes.go:407 +0x55
test/jni.CreateJVM.func3(0xe01a50, 0xc000035f18, 0x6, 0x6, 0xc000004280)
C:/Users/user/IdeaProjects/test/jni/jvm.go:41 +0x5d
test/jni.CreateJVM(0xc000035f18, 0x6, 0x6, 0x0)
C:/Users/user/IdeaProjects/test/jni/jvm.go:41 +0x14e
main.main()
C:/Users/user/IdeaProjects/test/main.go:16 +0xf3
rax 0x6
rbx 0x100800
rcx 0xcafebabe
rdi 0x1
rsi 0x0
rbp 0x6d16f550
rsp 0x86f258
r8 0x2865047b
r9 0x86f420
r10 0x2
r11 0x86f590
r12 0x3d8
r13 0x0
r14 0x0
r15 0x2030000
rip 0x286503b6
rflags 0x210246
cs 0x33
fs 0x53
gs 0x2b
I checked and confirmed that jvm.dll is loaded, both symbols are available, call to JNI_GetDefaultJavaVMInitArgs is successful. Any ideas where to look into and what is wrong with the call to JNI_CreateJavaVM?
OK, such a behavior is caused by https://github.com/golang/go/issues/20498. In order to bypass the error go source code needs to be adjusted: src/runtime/signal_windows.go#127 should be changed from var testingWER bool to var testingWER=true
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