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/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2007 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#pragma ident "%Z%%M% %I% %E% SMI"
#include <libdisasm.h>
#include <stdlib.h>
#include <stdio.h>
#include "dis_tables.h"
#include "libdisasm_impl.h"
struct dis_handle {
void *dh_data;
int dh_flags;
dis_lookup_f dh_lookup;
dis_read_f dh_read;
int dh_mode;
dis86_t dh_dis;
uint64_t dh_addr;
uint64_t dh_end;
};
/*
* Returns true if we are near the end of a function. This is a cheap hack at
* detecting NULL padding between functions. If we're within a few bytes of the
* next function, or past the start, then return true.
*/
static int
check_func(void *data)
{
dis_handle_t *dhp = data;
uint64_t start;
size_t len;
if (dhp->dh_lookup(dhp->dh_data, dhp->dh_addr, NULL, 0, &start, &len)
!= 0)
return (0);
if (start < dhp->dh_addr)
return (dhp->dh_addr > start + len - 0x10);
return (1);
}
static int
get_byte(void *data)
{
uchar_t byte;
dis_handle_t *dhp = data;
if (dhp->dh_read(dhp->dh_data, dhp->dh_addr, &byte, sizeof (byte)) !=
sizeof (byte))
return (-1);
dhp->dh_addr++;
return ((int)byte);
}
static int
do_lookup(void *data, uint64_t addr, char *buf, size_t buflen)
{
dis_handle_t *dhp = data;
return (dhp->dh_lookup(dhp->dh_data, addr, buf, buflen, NULL, NULL));
}
dis_handle_t *
dis_handle_create(int flags, void *data, dis_lookup_f lookup_func,
dis_read_f read_func)
{
dis_handle_t *dhp;
/*
* Validate architecture flags
*/
if (flags & ~(DIS_X86_SIZE16 | DIS_X86_SIZE32 | DIS_X86_SIZE64 |
DIS_OCTAL | DIS_NOIMMSYM)) {
(void) dis_seterrno(E_DIS_INVALFLAG);
return (NULL);
}
/*
* Create and initialize the internal structure
*/
if ((dhp = dis_zalloc(sizeof (struct dis_handle))) == NULL) {
(void) dis_seterrno(E_DIS_NOMEM);
return (NULL);
}
dhp->dh_lookup = lookup_func;
dhp->dh_read = read_func;
dhp->dh_flags = flags;
dhp->dh_data = data;
/*
* Initialize x86-specific architecture structure
*/
if (flags & DIS_X86_SIZE16)
dhp->dh_mode = SIZE16;
else if (flags & DIS_X86_SIZE64)
dhp->dh_mode = SIZE64;
else
dhp->dh_mode = SIZE32;
if (flags & DIS_OCTAL)
dhp->dh_dis.d86_flags = DIS_F_OCTAL;
dhp->dh_dis.d86_sprintf_func = snprintf;
dhp->dh_dis.d86_get_byte = get_byte;
dhp->dh_dis.d86_sym_lookup = do_lookup;
dhp->dh_dis.d86_check_func = check_func;
dhp->dh_dis.d86_data = dhp;
return (dhp);
}
int
dis_disassemble(dis_handle_t *dhp, uint64_t addr, char *buf, size_t buflen)
{
dhp->dh_addr = addr;
/* DIS_NOIMMSYM might not be set until now, so update */
if (dhp->dh_flags & DIS_NOIMMSYM)
dhp->dh_dis.d86_flags |= DIS_F_NOIMMSYM;
else
dhp->dh_dis.d86_flags &= ~DIS_F_NOIMMSYM;
if (dtrace_disx86(&dhp->dh_dis, dhp->dh_mode) != 0)
return (-1);
if (buf != NULL)
dtrace_disx86_str(&dhp->dh_dis, dhp->dh_mode, addr, buf,
buflen);
return (0);
}
void
dis_handle_destroy(dis_handle_t *dhp)
{
dis_free(dhp, sizeof (dis_handle_t));
}
void
dis_set_data(dis_handle_t *dhp, void *data)
{
dhp->dh_data = data;
}
void
dis_flags_set(dis_handle_t *dhp, int f)
{
dhp->dh_flags |= f;
}
void
dis_flags_clear(dis_handle_t *dhp, int f)
{
dhp->dh_flags &= ~f;
}
/* ARGSUSED */
int
dis_max_instrlen(dis_handle_t *dhp)
{
return (15);
}
#define MIN(a, b) ((a) < (b) ? (a) : (b))
/*
* Return the previous instruction. On x86, we have no choice except to
* disassemble everything from the start of the symbol, and stop when we have
* reached our instruction address. If we're not in the middle of a known
* symbol, then we return the same address to indicate failure.
*/
uint64_t
dis_previnstr(dis_handle_t *dhp, uint64_t pc, int n)
{
uint64_t *hist, addr, start;
int cur, nseen;
uint64_t res = pc;
if (n <= 0)
return (pc);
if (dhp->dh_lookup(dhp->dh_data, pc, NULL, 0, &start, NULL) != 0 ||
start == pc)
return (res);
hist = dis_zalloc(sizeof (uint64_t) * n);
for (cur = 0, nseen = 0, addr = start; addr < pc; addr = dhp->dh_addr) {
hist[cur] = addr;
cur = (cur + 1) % n;
nseen++;
/* if we cannot make forward progress, give up */
if (dis_disassemble(dhp, addr, NULL, 0) != 0)
goto done;
}
if (addr != pc) {
/*
* We scanned past %pc, but didn't find an instruction that
* started at %pc. This means that either the caller specified
* an invalid address, or we ran into something other than code
* during our scan. Virtually any combination of bytes can be
* construed as a valid Intel instruction, so any non-code bytes
* we encounter will have thrown off the scan.
*/
goto done;
}
res = hist[(cur + n - MIN(n, nseen)) % n];
done:
dis_free(hist, sizeof (uint64_t) * n);
return (res);
}
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