我有一個遺留 Java 應用程式，它使用 JNA 與 Matlab C Matrix API 進行互動。
/**
* Load a MAT-file. Must be synchronized because of native libraries calls.
*
* @param file MAT file
* @return map with the variables in the MAT file
*/
public static synchronized Map<String, MObj> load(final File file) {
if (file == null) {
throw new InvalidMatFileException(null, ERROR_MSG_FILE_NOT_FOUND);
}
if (!file.isFile()) {
throw new InvalidMatFileException(file.getName(), ERROR_MSG_FILE_NOT_FOUND);
}
final Map<String, MObj> vars = new HashMap<String, MObj>();
final Pointer matfile = MAT_LIB.matOpen(file.getAbsolutePath(), "r");
if (matfile == null) {
throw new InvalidMatFileException(file.getName(), ERROR_MSG_NOT_A_PROPER_MAT_FILE);
}
for (;;) {
final PointerByReference name = new PointerByReference();
final Pointer ar = MAT_LIB.matGetNextVariable(matfile, name);
if (ar == null) {
break;
}
final MObj obj = ToJava.convert(MX_LIB, ar);
MX_LIB.mxDestroyArray(ar);
vars.put(name.getValue().getString(0), obj);
}
MAT_LIB.matClose(matfile);
return vars;
}
//ToJava class has the following methods that are called from the code above
/**
* Convert a single mxArray
*
* @param mx MX library
* @param ar mxArray
* @return MObj instance
*/
public static MObj convert(MX mx, Pointer ar) {
final ToJava tr = new ToJava(mx);
tr.transform(ar);
return tr.obj;
}
/**
* Top-level transform
*
* @param ar mxArray
*/
private void transform(Pointer ar) {
final ClassID classID = ClassID.valueOf(mx.mxGetClassID(ar));
switch (classID) {
case DOUBLE:
transformDoubleArray(ar);
break;
在 for 回圈內部
ToJava.convert來電
mx.mxGetClassID(ar)
under the hood. This is defined in the api as
mxClassID mxGetClassID(const mxArray *pm);
where mxClassID is an enum. This is mapped in JNA as
int mxGetClassID(Pointer ar);
This is the exact piece of code causing the crash below
#
# A fatal error has been detected by the Java Runtime Environment:
#
# SIGSEGV (0xb) at pc=0x00007fbb7fcd45f0, pid=13363, tid=140445588428544
#
# JRE version: 6.0_45-b06
# Java VM: Java HotSpot(TM) 64-Bit Server VM (20.45-b01 mixed mode linux-amd64 compressed oops)
# Problematic frame:
# C [libmx.so 0x615f0] matrix::detail::noninlined::mx_array_api::mxGetClassID(mxArray_tag const*) 0x0
Register to memory mapping:
RAX=0x0000000000000000 is an unknown value
RBX=0x0000000000000008 is an unknown value
RCX=0x00007fbc04252a7a is an unknown value
RDX=0x00007fbc04252a7a is an unknown value
RSP=0x00007fbc09686888 is pointing into the stack for thread: 0x00007fbc04006800
RBP=0x00007fbc09686890 is pointing into the stack for thread: 0x00007fbc04006800
RSI=0x00007fbc04252a7a is an unknown value
RDI=0x0000000000000000 is an unknown value
R8 =0x00007fbc04252a7a is an unknown value
R9 =0x00007fbc04252a95 is an unknown value
R10=0x0000000000000000 is an unknown value
R11=0x00007fbb7fd46800: mxGetClassID 0 in /var/opt/Matlab_MCR/v91/bin/glnxa64/libmx.so at 0x00007fbb7fc73000
R12=0x00007fbc096869d0 is pointing into the stack for thread: 0x00007fbc04006800
R13=0x0000000000000008 is an unknown value
R14=0x0000000000000001 is an unknown value
R15=0x00007fbc096869b0 is pointing into the stack for thread: 0x00007fbc04006800
Stack: [0x00007fbc09589000,0x00007fbc0968a000], sp=0x00007fbc09686888, free space=1014k
Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
C [libmx.so 0x615f0] matrix::detail::noninlined::mx_array_api::mxGetClassID(mxArray_tag const*) 0x0
Java frames: (J=compiled Java code, j=interpreted, Vv=VM code)
j com.sun.jna.Native.invokeInt(Lcom/sun/jna/Function;JI[Ljava/lang/Object;)I 0
j com.sun.jna.Function.invoke([Ljava/lang/Object;Ljava/lang/Class;ZI)Ljava/lang/Object; 211
j com.sun.jna.Function.invoke(Ljava/lang/reflect/Method;[Ljava/lang/Class;Ljava/lang/Class;[Ljava/lang/Object;Ljava/util/Map;)Ljava/lang/Object; 271
j com.sun.jna.Library$Handler.invoke(Ljava/lang/Object;Ljava/lang/reflect/Method;[Ljava/lang/Object;)Ljava/lang/Object; 390
j com.sun.proxy.$Proxy12.mxGetClassID(Lcom/sun/jna/Pointer;)I 16
To sum it up,
- Linux 32 bits MCR (matlab compiler runtime) 32bit Java6/7/8 : works
- Windows 32 bits MCR (matlab compiler runtime) 32bit Java6/7/8 : works
- Windows 64 bits MCR (matlab compiler runtime) 64bit Java6/7/8 : works
- Linux 64 bits MCR (matlab compiler runtime) 64bit Java6/7/8 : JNA crashes
So far, I tried setting the LD_LIBRARY_PATH as well as the java.library.path and pointed both to the MCR location on the file system
/var/opt/Matlab_MCR/v91/runtime/glnxa64:/var/opt/Matlab_MCR/v91/bin/glnxa64:/var/opt/Matlab_MCR/v91/sys/os/glnxa64
Does anybody know how to troubleshoot this further?
uj5u.com熱心網友回復：
此問題中的代碼通過 JNA 呼叫 Matlab Compiler Runtime 公開的函式。事實證明，Matlab 端的介面已針對 64 位架構進行了更改。他們在其原生 API 簽名中使用 mwSize 型別，而我們的 JNA 映射使用 int。在 mwSize 等于 size_t 的 64 位機器上，int 將是 32 位。因此，JNA 映射和本機 API 簽名不再匹配。通過 JNA 反復呼叫這些函式后，甚至導致 JNA 崩潰。
解決方案的方向是在 Java 代碼中用 64 位整數替換 int。這可以通過擴展 JNA 提供的稱為 IntegerType 的抽象類并在適用的地方使用此擴展類來完成
來自 Matlab 的參考文章： https ://nl.mathworks.com/help/matlab/matlab_external/upgrading-mex-files-to-use-64-bit-api.html
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