Examples with MemoryAccessException com.ibm.dtfj.image.MemoryAccessException used on opensource projects

Example 16 with MemoryAccessException

use of com.ibm.dtfj.image.MemoryAccessException in project openj9 by eclipse.

the class JavaObject method getArrayReferences.

private List getArrayReferences(JavaArrayClass arrayClass) {
    List references = new ArrayList();
    try {
        String type = arrayClass.getComponentType().getName();
        if (type.equals("byte")) {
        // ignore byte arrays.
        } else if (type.equals("boolean")) {
        // ignore boolean arrays.
        } else if (type.equals("char")) {
        // ignore char arrays.
        } else if (type.equals("short")) {
        // ignore short arrays.
        } else if (type.equals("int")) {
        // ignore int arrays.
        } else if (type.equals("long")) {
        // ignore long arrays.
        } else if (type.equals("float")) {
        // ignore float arrays.
        } else if (type.equals("double")) {
        // ignore double arrays.
        } else {
            // must be Object array so handle it.
            Object[] dst = null;
            int arraySize = getArraySize();
            if (arraySize > 0) {
                // only deal with arrays that have space for Object references.
                dst = new Object[arraySize];
                try {
                    // copy the objects into our own array and then build the JavaReference
                    // objects from them.
                    arraycopy(0, dst, 0, arraySize);
                    for (int i = 0; i < dst.length; i++) {
                        if (null != dst[i]) {
                            String description = "Array Reference";
                            description = description + " [index:" + i + "]";
                            JavaReference jRef = new JavaReference(_javaVM, this, dst[i], description, JavaReference.REFERENCE_ARRAY_ELEMENT, JavaReference.HEAP_ROOT_UNKNOWN, JavaReference.REACHABILITY_STRONG);
                            references.add(jRef);
                        }
                    }
                } catch (MemoryAccessException e) {
                    // Memory access problems, so create a CorruptData object
                    // to describe the problem and add it to the container.
                    ImagePointer ptrInError = e.getPointer();
                    String message = e.getMessage();
                    references.add(new CorruptData(message, ptrInError));
                }
            }
        }
    } catch (CorruptDataException e) {
        // Corrupt data, so add it to the container.
        references.add(e.getCorruptData());
    }
    return references;
}

Example 17 with MemoryAccessException

use of com.ibm.dtfj.image.MemoryAccessException in project openj9 by eclipse.

the class JavaObject method getFieldReference.

private JavaReference getFieldReference(JavaField jField) {
    JavaReference jRef = null;
    try {
        String sigPrefix = jField.getSignature();
        JavaClass jClass = getJavaClass();
        if (sigPrefix.startsWith(JavaField.OBJECT_PREFIX_SIGNATURE) || sigPrefix.startsWith(JavaField.ARRAY_PREFIX_SIGNATURE)) {
            // this is an object reference.
            try {
                JavaObject jObject = (JavaObject) jField.getReferenceType(this);
                if (null != jObject) {
                    // build a JavaReference type and add the reference to the container.
                    String fieldName = jField.getName();
                    String description = "Object Reference";
                    if (null != fieldName) {
                        description = description + " [field name:" + fieldName + "]";
                    }
                    // Now figure out the reachability of the new reference.
                    // This will normally be "strong", except for the referent field of a reference,
                    // for which reachability will be weak, soft or phantom, depending on the concrete reference type.
                    int reachability = JavaReference.REACHABILITY_STRONG;
                    if ("referent".equals(fieldName) && "java/lang/ref/Reference".equals(jField.getDeclaringClass().getName())) {
                        if (_javaVM._weakReferenceClass != null && _javaVM._weakReferenceClass.isAncestorOf(jClass)) {
                            reachability = JavaReference.REACHABILITY_WEAK;
                        } else if (_javaVM._softReferenceClass != null && _javaVM._softReferenceClass.isAncestorOf(jClass)) {
                            reachability = JavaReference.REACHABILITY_SOFT;
                        } else if (_javaVM._phantomReferenceClass != null && _javaVM._phantomReferenceClass.isAncestorOf(jClass)) {
                            reachability = JavaReference.REACHABILITY_PHANTOM;
                        }
                    }
                    jRef = new JavaReference(_javaVM, this, jObject, description, JavaReference.REFERENCE_FIELD, JavaReference.HEAP_ROOT_UNKNOWN, reachability);
                }
            } catch (CorruptDataException e) {
            }
        }
    } catch (CorruptDataException e) {
    } catch (MemoryAccessException e) {
    }
    return jRef;
}

Example 18 with MemoryAccessException

use of com.ibm.dtfj.image.MemoryAccessException in project openj9 by eclipse.

the class JavaThread method getName.

/* (non-Javadoc)
	 * @see com.ibm.dtfj.java.JavaThread#getName()
	 */
public String getName() throws CorruptDataException {
    JavaObject theObject = getObject();
    if (null != theObject) {
        JavaClass threadClass = _javaLangThreadSuperclass();
        Iterator fields = threadClass.getDeclaredFields();
        while (fields.hasNext()) {
            JavaField oneField = (JavaField) fields.next();
            if (oneField.getName().equals("name")) {
                try {
                    return oneField.getString(theObject);
                } catch (MemoryAccessException e) {
                    throw new CorruptDataException(new CorruptData("unable to read memory for 'name' field", null));
                }
            }
        }
        throw new CorruptDataException(new CorruptData("unable to find 'name' field", null));
    } else {
        return "vmthread @" + _jniEnv.getAddress();
    }
}

Example 19 with MemoryAccessException

use of com.ibm.dtfj.image.MemoryAccessException in project openj9 by eclipse.

the class JavaHeapRegion method getObjectAtAddress.

public JavaObject getObjectAtAddress(ImagePointer address) throws CorruptDataException, IllegalArgumentException {
    JavaObject object = null;
    if ((null != address) && (0 != address.getAddress())) {
        // try the special objects cache first...
        JavaObject specialObject = _javaVM.getSpecialObject(address);
        if (null != specialObject) {
            return specialObject;
        }
        // CMVC 173262 - check alignment
        if ((address.getAddress() & (_objectAlignment - 1)) != 0) {
            throw new IllegalArgumentException("Invalid alignment for JavaObject should be " + _objectAlignment + " aligned. Address = " + address.toString());
        }
        long arrayletIdentificationBitmask = 0;
        long arrayletIdentificationResult = 0;
        int arrayletIdentificationWidth = 0;
        int arrayletIdentificationOffset = 0;
        int arrayletSpineSize = 0;
        long arrayletLeafSize = 0;
        arrayletIdentificationBitmask = _parentHeap.getArrayletIdentificationBitmask();
        arrayletIdentificationResult = _parentHeap.getArrayletIdentificationResult();
        arrayletIdentificationWidth = _parentHeap.getArrayletIdentificationWidth();
        arrayletIdentificationOffset = _parentHeap.getArrayletIdentificationOffset();
        arrayletSpineSize = getArrayletSpineSize();
        arrayletLeafSize = getArrayletLeafSize();
        boolean isArraylet = false;
        if (0 != arrayletIdentificationResult) {
            // note that this may be an arraylet so we need to do some extra work here
            long maskedFlags = 0;
            if (4 == arrayletIdentificationWidth) {
                try {
                    maskedFlags = 0xFFFFFFFFL & (long) (address.getIntAt(arrayletIdentificationOffset));
                } catch (MemoryAccessException e) {
                    throw new CorruptDataException(new CorruptData("unable to access object flags", address));
                }
            } else if (8 == arrayletIdentificationWidth) {
                try {
                    maskedFlags = address.getLongAt(arrayletIdentificationOffset);
                } catch (MemoryAccessException e) {
                    throw new CorruptDataException(new CorruptData("unable to access object flags", address));
                }
            } else {
                // this size cannot be read without exposing endian of the underlying core
                System.err.println("Arraylet identification width is invalid: " + arrayletIdentificationWidth + " (should be 4 or 8)");
            }
            isArraylet = arrayletIdentificationResult == (arrayletIdentificationBitmask & maskedFlags);
        }
        object = new com.ibm.dtfj.java.j9.JavaObject(_javaVM, address, _parentHeap, arrayletSpineSize, arrayletLeafSize, isArraylet, _objectAlignment);
    }
    return object;
}

Example 20 with MemoryAccessException

use of com.ibm.dtfj.image.MemoryAccessException in project openj9 by eclipse.

the class JavaObject method getPersistentHashcode.

/* (non-Javadoc)
	 * @see com.ibm.dtfj.java.JavaObject#getPersistentHashcode()
	 */
public long getPersistentHashcode() throws DataUnavailable, CorruptDataException {
    // this is a terrible way to do this since we know that it _will_ _break_ in the future.  It is, however, the best that we can do
    if (_javaVM.objectShouldInferHash()) {
        try {
            int flags = ((com.ibm.dtfj.java.j9.JavaAbstractClass) getJavaClass()).readFlagsFromInstance(this);
            // now mask out the non-hash bits, shift and return
            // high 15 bits, omitting most significant
            int twoBytes = flags & 0x7FFF0000;
            long hash = (twoBytes >> 16) | twoBytes;
            return hash;
        } catch (MemoryAccessException e) {
            // if we can't access the memory, the core must be corrupt
            throw new CorruptDataException(new CorruptData("Address in object header but unreadable", _basePointer));
        }
    } else {
        throw new DataUnavailable("Unknown hash strategy for this VM version");
    }
}