usr/src/lib/libdisasm/common/dis_i386.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21
  22 /*
  23  * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  * Copyright 2012 Joshua M. Clulow <josh@sysmgr.org>
  26  * Copyright 2015 Nexenta Systems, Inc.  All rights reserved.
  27  */
  28
  29 #include <libdisasm.h>
  30
  31 #include "dis_tables.h"
  32 #include "libdisasm_impl.h"
  33
  34 typedef struct dis_handle_i386 {
  35         int             dhx_mode;
  36         dis86_t         dhx_dis;
  37         uint64_t        dhx_end;
  38 } dis_handle_i386_t;
  39
  40 /*
  41  * Returns true if we are near the end of a function.  This is a cheap hack at
  42  * detecting NULL padding between functions.  If we're within a few bytes of the
  43  * next function, or past the start, then return true.
  44  */
  45 static int
  46 check_func(void *data)
  47 {
  48         dis_handle_t *dhp = data;
  49         uint64_t start;
  50         size_t len;
  51
  52         if (dhp->dh_lookup(dhp->dh_data, dhp->dh_addr, NULL, 0, &start, &len)
  53             != 0)
  54                 return (0);
  55
  56         if (start < dhp->dh_addr)
  57                 return (dhp->dh_addr > start + len - 0x10);
  58
  59         return (1);
  60 }
  61
  62 static int
  63 get_byte(void *data)
  64 {
  65         uchar_t byte;
  66         dis_handle_t *dhp = data;
  67
  68         if (dhp->dh_read(dhp->dh_data, dhp->dh_addr, &byte, sizeof (byte)) !=
  69             sizeof (byte))
  70                 return (-1);
  71
  72         dhp->dh_addr++;
  73
  74         return ((int)byte);
  75 }
  76
  77 static int
  78 do_lookup(void *data, uint64_t addr, char *buf, size_t buflen)
  79 {
  80         dis_handle_t *dhp = data;
  81
  82         return (dhp->dh_lookup(dhp->dh_data, addr, buf, buflen, NULL, NULL));
  83 }
  84
  85 static void
  86 dis_i386_handle_detach(dis_handle_t *dhp)
  87 {
  88         dis_free(dhp->dh_arch_private, sizeof (dis_handle_i386_t));
  89         dhp->dh_arch_private = NULL;
  90 }
  91
  92 static int
  93 dis_i386_handle_attach(dis_handle_t *dhp)
  94 {
  95         dis_handle_i386_t *dhx;
  96
  97         /*
  98          * Validate architecture flags
  99          */
 100         if (dhp->dh_flags & ~(DIS_X86 |
 101             DIS_SIZE_16 | DIS_SIZE_32 | DIS_SIZE_64 |
 102             DIS_OCTAL | DIS_NOIMMSYM)) {
 103                 (void) dis_seterrno(E_DIS_INVALFLAG);
 104                 return (-1);
 105         }
 106
 107         /*
 108          * Create and initialize the internal structure
 109          */
 110         if ((dhx = dis_zalloc(sizeof (dis_handle_i386_t))) == NULL) {
 111                 (void) dis_seterrno(E_DIS_NOMEM);
 112                 return (-1);
 113         }
 114         dhp->dh_arch_private = dhx;
 115
 116         /*
 117          * Initialize x86-specific architecture structure
 118          */
 119         if (dhp->dh_flags & DIS_SIZE_16)
 120                 dhx->dhx_mode = SIZE16;
 121         else if (dhp->dh_flags & DIS_SIZE_64)
 122                 dhx->dhx_mode = SIZE64;
 123         else
 124                 dhx->dhx_mode = SIZE32;
 125
 126         if (dhp->dh_flags & DIS_OCTAL)
 127                 dhx->dhx_dis.d86_flags = DIS_F_OCTAL;
 128
 129         dhx->dhx_dis.d86_sprintf_func = dis_snprintf;
 130         dhx->dhx_dis.d86_get_byte = get_byte;
 131         dhx->dhx_dis.d86_sym_lookup = do_lookup;
 132         dhx->dhx_dis.d86_check_func = check_func;
 133
 134         dhx->dhx_dis.d86_data = dhp;
 135
 136         return (0);
 137 }
 138
 139 static int
 140 dis_i386_disassemble(dis_handle_t *dhp, uint64_t addr, char *buf,
 141     size_t buflen)
 142 {
 143         dis_handle_i386_t *dhx = dhp->dh_arch_private;
 144         dhp->dh_addr = addr;
 145
 146         /* DIS_NOIMMSYM might not be set until now, so update */
 147         if (dhp->dh_flags & DIS_NOIMMSYM)
 148                 dhx->dhx_dis.d86_flags |= DIS_F_NOIMMSYM;
 149         else
 150                 dhx->dhx_dis.d86_flags &= ~DIS_F_NOIMMSYM;
 151
 152         if (dtrace_disx86(&dhx->dhx_dis, dhx->dhx_mode) != 0)
 153                 return (-1);
 154
 155         if (buf != NULL)
 156                 dtrace_disx86_str(&dhx->dhx_dis, dhx->dhx_mode, addr, buf,
 157                     buflen);
 158
 159         return (0);
 160 }
 161
 162 /* ARGSUSED */
 163 static int
 164 dis_i386_max_instrlen(dis_handle_t *dhp)
 165 {
 166         return (15);
 167 }
 168
 169 /* ARGSUSED */
 170 static int
 171 dis_i386_min_instrlen(dis_handle_t *dhp)
 172 {
 173         return (1);
 174 }
 175
 176 static int
 177 dis_i386_supports_flags(int flags)
 178 {
 179         if ((flags & DIS_ARCH_MASK) == DIS_X86 &&
 180             DIS_SIZE_CHECK(flags, DIS_SIZE_16 | DIS_SIZE_32 | DIS_SIZE_64))
 181                 return (1);
 182
 183         return (0);
 184 }
 185
 186 dis_arch_t dis_arch_i386 = {
 187         .da_supports_flags      = dis_i386_supports_flags,
 188         .da_handle_attach       = dis_i386_handle_attach,
 189         .da_handle_detach       = dis_i386_handle_detach,
 190         .da_disassemble         = dis_i386_disassemble,
 191         .da_min_instrlen        = dis_i386_min_instrlen,
 192         .da_max_instrlen        = dis_i386_max_instrlen,
 193 };