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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "libdis.h"
#include "ia32_insn.h"
#include "ia32_invariant.h"
#include "x86_operand_list.h"
#ifdef _MSC_VER
#define snprintf _snprintf
#define inline __inline
#endif
unsigned int x86_disasm( unsigned char *buf, unsigned int buf_len,
uint32_t buf_rva, unsigned int offset,
x86_insn_t *insn ){
int len, size;
unsigned char bytes[MAX_INSTRUCTION_SIZE];
if ( ! buf || ! insn || ! buf_len ) {
/* caller screwed up somehow */
return 0;
}
/* ensure we are all NULLed up */
memset( insn, 0, sizeof(x86_insn_t) );
insn->addr = buf_rva + offset;
insn->offset = offset;
/* default to invalid insn */
insn->type = insn_invalid;
insn->group = insn_none;
if ( offset >= buf_len ) {
/* another caller screwup ;) */
x86_report_error(report_disasm_bounds, (void*)(long)(buf_rva+offset));
return 0;
}
len = buf_len - offset;
/* copy enough bytes for disassembly into buffer : this
* helps prevent buffer overruns at the end of a file */
memset( bytes, 0, MAX_INSTRUCTION_SIZE );
memcpy( bytes, &buf[offset], (len < MAX_INSTRUCTION_SIZE) ? len :
MAX_INSTRUCTION_SIZE );
/* actually do the disassembly */
/* TODO: allow switching when more disassemblers are added */
size = ia32_disasm_addr( bytes, len, insn);
/* check and see if we had an invalid instruction */
if (! size ) {
x86_report_error(report_invalid_insn, (void*)(long)(buf_rva+offset));
return 0;
}
/* check if we overran the end of the buffer */
if ( size > len ) {
x86_report_error( report_insn_bounds, (void*)(long)(buf_rva + offset));
MAKE_INVALID( insn, bytes );
return 0;
}
/* fill bytes field of insn */
memcpy( insn->bytes, bytes, size );
return size;
}
unsigned int x86_disasm_range( unsigned char *buf, uint32_t buf_rva,
unsigned int offset, unsigned int len,
DISASM_CALLBACK func, void *arg ) {
x86_insn_t insn;
unsigned int buf_len, size, count = 0, bytes = 0;
/* buf_len is implied by the arguments */
buf_len = len + offset;
while ( bytes < len ) {
size = x86_disasm( buf, buf_len, buf_rva, offset + bytes,
&insn );
if ( size ) {
/* invoke callback if it exists */
if ( func ) {
(*func)( &insn, arg );
}
bytes += size;
count ++;
} else {
/* error */
bytes++; /* try next byte */
}
x86_oplist_free( &insn );
}
return( count );
}
static inline int follow_insn_dest( x86_insn_t *insn ) {
if ( insn->type == insn_jmp || insn->type == insn_jcc ||
insn->type == insn_call || insn->type == insn_callcc ) {
return(1);
}
return(0);
}
static inline int insn_doesnt_return( x86_insn_t *insn ) {
return( (insn->type == insn_jmp || insn->type == insn_return) ? 1: 0 );
}
static int32_t internal_resolver( x86_op_t *op, x86_insn_t *insn ){
int32_t next_addr = -1;
if ( x86_optype_is_address(op->type) ) {
next_addr = op->data.sdword;
} else if ( op->type == op_relative_near ) {
next_addr = insn->addr + insn->size + op->data.relative_near;
} else if ( op->type == op_relative_far ) {
next_addr = insn->addr + insn->size + op->data.relative_far;
}
return( next_addr );
}
unsigned int x86_disasm_forward( unsigned char *buf, unsigned int buf_len,
uint32_t buf_rva, unsigned int offset,
DISASM_CALLBACK func, void *arg,
DISASM_RESOLVER resolver, void *r_arg ){
x86_insn_t insn;
x86_op_t *op;
int32_t next_addr;
uint32_t next_offset;
unsigned int size, count = 0, bytes = 0, cont = 1;
while ( cont && bytes < buf_len ) {
size = x86_disasm( buf, buf_len, buf_rva, offset + bytes,
&insn );
if ( size ) {
/* invoke callback if it exists */
if ( func ) {
(*func)( &insn, arg );
}
bytes += size;
count ++;
} else {
/* error */
bytes++; /* try next byte */
}
if ( follow_insn_dest(&insn) ) {
op = x86_get_dest_operand( &insn );
next_addr = -1;
/* if caller supplied a resolver, use it to determine
* the address to disassemble */
if ( resolver ) {
next_addr = resolver(op, &insn, r_arg);
} else {
next_addr = internal_resolver(op, &insn);
}
if (next_addr != -1 ) {
next_offset = next_addr - buf_rva;
/* if offset is in this buffer... */
if ( (uint32_t)next_addr >= buf_rva &&
next_offset < buf_len ) {
/* go ahead and disassemble */
count += x86_disasm_forward( buf,
buf_len,
buf_rva,
next_offset,
func, arg,
resolver, r_arg );
} else {
/* report unresolved address */
x86_report_error( report_disasm_bounds,
(void*)(long)next_addr );
}
}
} /* end follow_insn */
if ( insn_doesnt_return(&insn) ) {
/* stop disassembling */
cont = 0;
}
x86_oplist_free( &insn );
}
return( count );
}
/* invariant instruction representation */
size_t x86_invariant_disasm( unsigned char *buf, int buf_len,
x86_invariant_t *inv ){
if (! buf || ! buf_len || ! inv ) {
return(0);
}
return ia32_disasm_invariant(buf, buf_len, inv);
}
size_t x86_size_disasm( unsigned char *buf, unsigned int buf_len ) {
if (! buf || ! buf_len ) {
return(0);
}
return ia32_disasm_size(buf, buf_len);
}