classread.cc

功能较全面的反汇编器：反汇编器ht-2.0.15.tar.gz

/*
 *	HT Editor
 *	classread.cc
 *
 *	Copyright (C) 2001 Stanley Gambarin <[e-mail]>
 *	Copyright (C) 2002 Sebastian Biallas ([e-mail])
 *
 *	This program is free software; you can redistribute it and/or modify
 *	it under the terms of the GNU General Public License version 2 as
 *	published by the Free Software Foundation.
 *
 *	This program is distributed in the hope that it will be useful,
 *	but WITHOUT ANY WARRANTY; without even the implied warranty of
 *	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *	GNU General Public License for more details.
 *
 *	You should have received a copy of the GNU General Public License
 *	along with this program; if not, write to the Free Software
 *	Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <stdlib.h>
#include <string.h>

#include "analy.h"
#include "class.h"
#include "strtools.h"
#include "snprintf.h"
#include "stream.h"


static u1 inp[4];
static u4 offset;
#define cls_read(a, b, c, d) (((b) != ((d)->read((a), (b)*(c)))) \
				? (0) : (offset+=(b), (b)))
#define READ1() \
  (((inp[0]=inp[1]=inp[2]=inp[3]=0),  \
   (1 == cls_read (inp, 1, 1, htio))) \
   ? (u1)(inp[0]) : 0)
#define READ2() \
  (((inp[0]=inp[1]=inp[2]=inp[3]=0),  \
   (2 == cls_read (inp, 2, 1, htio))) \
   ? ((((u2)inp[0])<<8)|inp[1]) : 0)
#define READ4() \
  (((inp[0]=inp[1]=inp[2]=inp[3]=0),  \
   (4 == cls_read (inp, 4, 1, htio))) \
   ? (((((((u4)inp[0]<<8)|inp[1])<<8)|inp[2])<<8)|inp[3]) : 0)
#define READN(inb, n) cls_read (inb, n, 1, htio)
#define SKIPN(n) {u1 b; for (u4 i=0; i<n; i++) {cls_read(&b, 1, 1, htio);}}

ClassMethod::ClassMethod(char *n, char *d, ClassAddress s, uint l, int f,
			int e_len, exception_info *e)
{
	name = n;
	start = s;
	type = d;
	length = l;
	flags = f;
	exctbl_len = e_len;
	exctbl = e;
}

int ClassMethod::compareTo(const Object *obj) const
{
	ClassMethod *cm = (ClassMethod*)obj;
	if ((start + length - 1) < cm->start) return -1;
	if (start > (cm->start + cm->length - 1)) return 1;
	return 0;
}

ClassField::ClassField(char *n, char *d, int f)
{
	name = n;
	type = d;
	flags = f;
}

/* extract name from a utf8 constant pool entry */
static char *get_string(Stream *htio, classfile *clazz, uint index)
{
	return (index < clazz->cpool_count) ? clazz->cpool[index]->value.string : (char*)"?";
}

/* extract name from a utf8 constant pool class entry */
static char *get_class_name(Stream *htio, classfile *clazz, uint index)
{
	return (index < clazz->cpool_count) ? get_string(htio, clazz, clazz->cpool[index]->value.llval[0]): (char*)"?";
}

/* extract name from a utf8 constant pool class entry */
static void get_name_and_type(Stream *htio, classfile *clazz, uint index, char *name, char *type)
{
	strcpy(name, (index < clazz->cpool_count) ? get_string(htio, clazz, clazz->cpool[index]->value.llval[0]) : "?");
	strcpy(type, (index < clazz->cpool_count) ? get_string(htio, clazz, clazz->cpool[index]->value.llval[1]) : "?");
}

/* read and return constant pool entry */
static cp_info *read_cpool_entry(Stream *htio, classfile *clazz)
{
	cp_info *cp;
	u2 idx;

	cp         = ht_malloc(sizeof (*cp));
	cp->offset = offset;
	cp->tag    = READ1();
	switch (cp->tag) {
	case CONSTANT_Utf8:
		idx = READ2();
		cp->value.string = ht_malloc(idx+1);
		cls_read(cp->value.string, idx, 1, htio);
		cp->value.string[idx] = 0;
		break;
	case CONSTANT_Integer:
	case CONSTANT_Float:
		cp->value.ival = READ4();
		break;
	case CONSTANT_Long:
	case CONSTANT_Double:
		cp->value.llval[0] = READ4();
		cp->value.llval[1] = READ4();
		break;
	case CONSTANT_Class:
	case CONSTANT_String:
		cp->value.llval[0] = READ2();
		break;
	case CONSTANT_Fieldref:
	case CONSTANT_Methodref:
	case CONSTANT_InterfaceMethodref:
	case CONSTANT_NameAndType:
		cp->value.llval[0] = READ2();
		cp->value.llval[1] = READ2();
		break;
	default:
		return NULL;
	}
	return (cp);
}

/* read and return an attribute read */
attrib_info *attribute_read(Stream *htio, classfile *clazz)
{
	attrib_info *a;
	u4 len;
	char *aname;

	a = ht_malloc(sizeof (*a));
	if (!a) {
		return NULL;
	}
	a->offset    = offset;
	a->name      = READ2();
	a->len = len = READ4();

	aname = get_string(htio, clazz, a->name);
	if (!strcmp (aname, "ConstantValue")) {
		a->tag = ATTRIB_ConstantValue;
	} else if (!strcmp(aname, "Code")) {
		a->tag = ATTRIB_Code;
		a->code.max_stack = READ2();
		a->code.max_locals = READ2();
		a->code.len = READ4();
		a->code.start = offset;
		len -= 2+2+4+a->code.len;
		SKIPN(a->code.len);
		a->code.exctbl_len = READ2();
		if (a->code.exctbl_len) {
			a->code.exctbl = ht_malloc(a->code.exctbl_len * sizeof(exception_info));
			for (uint i=0; i < a->code.exctbl_len; i++) {
				a->code.exctbl[i].start_pc = READ2();
				a->code.exctbl[i].end_pc = READ2();
				a->code.exctbl[i].handler_pc = READ2();
				a->code.exctbl[i].catch_type = READ2();
			}
		}
		len -= 2 + 8*a->code.exctbl_len;
	} else if (!strcmp(aname, "Signature")) {
		a->tag = ATTRIB_Signature;
		a->signature = READ2();
		len -= 2;
	} else if (!strcmp(aname, "Exceptions")) {
		a->tag = ATTRIB_Exceptions;
	} else if (!strcmp(aname, "InnerClasses")) {
		a->tag = ATTRIB_InnerClasses;
	} else if (!strcmp(aname, "Synthetic")) {
		a->tag = ATTRIB_Synthetic;
	} else if (!strcmp(aname, "SourceFile")) {
		a->tag = ATTRIB_SourceFile;
	} else if (!strcmp(aname, "LineNumberTable")) {
		a->tag = ATTRIB_LineNumberTable;
	} else if (!strcmp(aname, "LocalVariableTable")) {
		a->tag = ATTRIB_LocalVariableTable;
	} else if (!strcmp(aname, "Deprecated")) {
		a->tag = ATTRIB_Deprecated;
	}
	SKIPN(len);
	return (a);
}

/* read and return method info */
static mf_info *read_fieldmethod(Stream *htio, ht_class_shared_data *shared)
{
	mf_info *m;
	u2 idx;
	classfile *clazz = shared->file;

	m = (mf_info *)calloc(1, sizeof (*m));
	if (!m) {
		return NULL;
	}
	m->offset = offset;
	m->flags = READ2();
	m->name = get_string(htio, clazz, READ2());
	m->desc = get_string(htio, clazz, READ2());
	m->attribs_count = idx = READ2();
	if (idx) {
		m->attribs = ht_malloc(idx * sizeof (*(m->attribs)));
		if (!m->attribs) {
			return NULL;
		}
		for (int i=0; i < (int)idx; i++) {
			m->attribs[i] = attribute_read(htio, clazz);
		}
	}
	return m;
}

/* read and return classfile */
ht_class_shared_data *class_read(File *htio)
{
	ht_class_shared_data *shared;
	classfile *clazz;
	u2 count;
	u2 cpcount, index;

	clazz = ht_malloc(sizeof (*clazz));
	if (!clazz) {
		return NULL;
	}
	shared = ht_malloc(sizeof (ht_class_shared_data));
	shared->file = clazz;
	shared->methods = new AVLTree(true);
	shared->fields = new Array(true);
	shared->valid = new Area();
	shared->valid->init();
	shared->initialized = new Area();
	shared->initialized->init();
	clazz->offset = offset = 0;
	clazz->magic  = READ4();
	if (clazz->magic != 0xCAFEBABE) {
		return NULL;
	}
	clazz->minor_version = READ2();
	clazz->major_version = READ2();
	count = clazz->cpool_count = READ2();
	clazz->cpool = ht_malloc((count+1) * sizeof (*(clazz->cpool)));
	if (!clazz->cpool) {
		return NULL;
	}
	cpcount = clazz->cpool_count;
	for (int i=1; i<(int)count; i++) {
		clazz->cpool[i] = read_cpool_entry(htio, clazz);
		if ((clazz->cpool[i]->tag == CONSTANT_Long) ||
			(clazz->cpool[i]->tag == CONSTANT_Double)) {
			i++;
		}
	}
	clazz->coffset = offset;
	clazz->access_flags = READ2();
	shared->flags = clazz->access_flags;
	index = READ2();
	clazz->this_class = index;
	index = READ2();
	clazz->super_class = index;
	count = clazz->interfaces_count = READ2();
	shared->classinfo.interfaces = NULL;
	shared->classinfo.thisclass = get_class_name(htio, clazz, clazz->this_class);
	if (strcmp(shared->classinfo.thisclass, "?") == 0) return NULL;
	shared->classinfo.superclass = get_class_name(htio, clazz, clazz->super_class);
	if (strcmp(shared->classinfo.superclass, "?") == 0) return NULL;
	if (count) {
		clazz->interfaces = ht_malloc(count * sizeof (*(clazz->interfaces)));
		if (!clazz->interfaces) return NULL;
		shared->classinfo.interfaces = new Array(true);
		for (int i=0; i < (int)count; i++) {
			index = READ2();
			clazz->interfaces[i] = index;
			shared->classinfo.interfaces->insert(new String(get_class_name(htio, clazz, index)));
		}
	} else {
		clazz->interfaces = 0;
	}
	clazz->foffset = offset;
	count = clazz->fields_count = READ2();
	if (count) {
		clazz->fields = ht_malloc(count * sizeof (*(clazz->fields)));
		if (!clazz->fields) {
			return NULL;
		}
		for (int i=0; i < (int)count; i++) {
			mf_info *m = read_fieldmethod(htio, shared);
			clazz->fields[i] = m;
			ClassField *cf = new ClassField(m->name, m->desc, m->flags);
			int acount = m->attribs_count;
			for (int j=0; j < acount; j++) {
				attrib_info *ai = m->attribs[j];
				if (ai->tag == ATTRIB_Signature) {
					cf->addsig(get_string(htio, shared->file, ai->signature));
				}
			}
			shared->fields->insert(cf);
		}
	} else {
		clazz->fields = 0;
	}
	clazz->moffset = offset;
	count = clazz->methods_count = READ2();
	if (count) {
		clazz->methods = ht_malloc(count * sizeof (*(clazz->methods)));
		if (!clazz->methods) {
			return NULL;
		}
		for (int i=0; i < (int)count; i++) {
			mf_info *m = read_fieldmethod(htio, shared);
			clazz->methods[i] = m;
			int acount = m->attribs_count;
			bool ok = false;
			ClassMethod *cm = NULL;
			for (int j=0; j < acount; j++) {
				attrib_info *ai = m->attribs[j];
				if (ai->tag == ATTRIB_Code) {
					cm = new ClassMethod(m->name, m->desc, 
						ai->code.start, ai->code.len, m->flags, 
						ai->code.exctbl_len, ai->code.exctbl);
					shared->methods->insert(cm);
					AddressFlat32 a1(ai->code.start);
					AddressFlat32 a2(ai->code.start+ai->code.len);
					shared->initialized->add(&a1, &a2);
					shared->valid->add(&a1, &a2);
					ok = true;
				} else if (ai->tag == ATTRIB_Signature && cm) {
					cm->addsig(get_string(htio, shared->file, ai->signature));
				}
			}
			if (!ok) {
				// fake abstract method
				ClassMethod *cm = new ClassMethod(m->name, m->desc, offset, 1, m->flags, 0, NULL);
				shared->methods->insert(cm);
				Address *a1 = new AddressFlat32(offset);
				Address *a2 = new AddressFlat32(offset+1);
				shared->valid->add(a1, a2);
				delete a1;
				delete a2;
			}
		}
	} else {
		clazz->methods = 0;
	}