usr.bin/doscmd/trace.c

   1 /*
   2  * Copyright (c) 1992, 1993, 1996
   3  *      Berkeley Software Design, Inc.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by Berkeley Software
  16  *      Design, Inc.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY Berkeley Software Design, Inc. ``AS IS'' AND
  19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  21  * ARE DISCLAIMED.  IN NO EVENT SHALL Berkeley Software Design, Inc. BE LIABLE
  22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  28  * SUCH DAMAGE.
  29  *
  30  *      BSDI trace.c,v 2.2 1996/04/08 19:33:07 bostic Exp
  31  *
  32  * $FreeBSD: src/usr.bin/doscmd/trace.c,v 1.3.2.1 2002/04/25 11:04:51 tg Exp $
  33  * $DragonFly: src/usr.bin/doscmd/trace.c,v 1.2 2003/06/17 06:29:26 dillon Exp $
  34  */
  35
  36 #include "doscmd.h"
  37 #include "trap.h"
  38
  39 int             tmode = 0;
  40
  41 static u_short  *saddr;
  42 static u_char   *iaddr, ibyte;
  43
  44 /* locals */
  45 static void             printtrace(regcontext_t *REGS, char *buf);
  46 static inline void      showstate(long, long, char);
  47
  48 /*
  49  * Before exiting to VM86 mode:
  50  * 1) Always set the trap flag.
  51  * 2) If this is a POPF or IRET instruction, set the trap flag in the saved
  52  *    flag state on the stack.
  53  * On enterint from VM86 mode:
  54  * 1) Restore the trap flag from our saved flag state.
  55  * 2) If we just finished a POPF or IRET unstruction, patch the saved flag
  56  *    state on the stack.
  57  */
  58
  59 int tracetype;
  60
  61 int
  62 resettrace(regcontext_t *REGS)
  63 {
  64     if ((R_EFLAGS & PSL_VM) == 0)               /* invalid unless handling a vm86 process */
  65         return (0);
  66
  67 /* XXX */ return 1;
  68
  69     switch (tracetype) {
  70     case 1:
  71         R_EFLAGS &= ~PSL_T;
  72         tracetype = 0;
  73         return (1);
  74
  75     case 2:
  76         if ((u_char *)MAKEPTR(R_CS, R_IP - 1) == iaddr)
  77             R_IP --;
  78         *iaddr = ibyte;
  79         tracetype = 0;
  80         return (1);
  81
  82     case 3:
  83     case 4:
  84         R_EFLAGS &= ~PSL_T;
  85         *saddr &= ~PSL_T;
  86         tracetype = 0;
  87         return (1);
  88     }
  89     return (0);
  90 }
  91
  92 void
  93 tracetrap(regcontext_t *REGS)
  94 {
  95     u_char *addr;
  96     int n;
  97     char buf[100];
  98
  99     if ((R_EFLAGS & PSL_VM) == 0)
 100         return;
 101
 102     addr = (u_char *)MAKEPTR(R_CS, R_IP);
 103
 104     n = i386dis(R_CS, R_IP, addr, buf, 0);
 105     printtrace(REGS, buf);
 106
 107 /* XXX */
 108     R_EFLAGS |= PSL_T;
 109     return;
 110 /* XXX */
 111
 112
 113     switch (addr[0]) {
 114     case REPNZ:
 115     case REPZ:
 116         tracetype = 2;
 117         iaddr = (u_char *)MAKEPTR(R_CS, R_IP + n);
 118         break;
 119     case PUSHF:
 120         tracetype = 4;
 121         saddr = (u_short *)MAKEPTR(R_SS, R_SP - 2);
 122         break;
 123     case POPF:
 124         tracetype = 3;
 125         saddr = (u_short *)MAKEPTR(R_SS, R_SP + 0);
 126         break;
 127     case IRET:
 128         tracetype = 3;
 129         saddr = (u_short *)MAKEPTR(R_SS, R_SP + 4);
 130 #if 0
 131         printf("IRET: %04x %04x %04x\n",
 132                ((u_short *)MAKEPTR(R_SS, R_SP))[0],
 133                ((u_short *)MAKEPTR(R_SS, R_SP))[1],
 134                ((u_short *)MAKEPTR(R_SS, R_SP))[2]);
 135 #endif
 136         break;
 137     case OPSIZ:
 138         switch (addr[1]) {
 139         case PUSHF:
 140             tracetype = 4;
 141             saddr = (u_short *)MAKEPTR(R_SS, R_SP - 4);
 142             break;
 143         case POPF:
 144             tracetype = 3;
 145             saddr = (u_short *)MAKEPTR(R_SS, R_SP + 0);
 146             break;
 147         case IRET:
 148             tracetype = 3;
 149             saddr = (u_short *)MAKEPTR(R_SS, R_SP + 8);
 150             break;
 151         default:
 152             tracetype = 1;
 153             break;
 154         }
 155     default:
 156         tracetype = 1;
 157         break;
 158     }
 159
 160     switch (tracetype) {
 161     case 1:
 162     case 4:
 163         if (R_EFLAGS & PSL_T)
 164             tracetype = 0;
 165         else
 166             R_EFLAGS |= PSL_T;
 167         break;
 168     case 2:
 169         if (*iaddr == TRACETRAP)
 170             tracetype = 0;
 171         else {
 172             ibyte = *iaddr;
 173             *iaddr = TRACETRAP;
 174         }
 175         break;
 176     case 3:
 177         R_EFLAGS |= PSL_T;
 178         if (*saddr & PSL_T)
 179             tracetype = 0;
 180         else
 181             *saddr |= PSL_T;
 182         break;
 183     }
 184 }
 185
 186 static inline void
 187 showstate(long flags, long flag, char f)
 188 {
 189     putc((flags & flag) ? f : ' ', debugf);
 190 }
 191
 192 static void
 193 printtrace(regcontext_t *REGS, char *buf)
 194 {
 195
 196     static int first = 1;
 197 #if BIG_DEBUG
 198     u_char *addr = (u_char *)MAKEPTR(R_CS, R_IP);
 199 #endif
 200
 201     if (first) {
 202         fprintf(debugf, "%4s:%4s "
 203 #if BIG_DEBUG
 204                ".. .. .. .. .. .. "
 205 #endif
 206                "%-30s "
 207                "%4s %4s %4s %4s %4s %4s %4s %4s %4s %4s %4s\n",
 208                 "CS", "IP", "instruction",
 209                 "AX", "BX", "CX", "DX",
 210                 "DI", "SI", "SP", "BP",
 211                 "SS", "DS", "ES");
 212         first = 0;
 213     }
 214
 215     fprintf(debugf, "%04x:%04x "
 216 #if BIG_DEBUG
 217             "%02x %02x %02x %02x %02x %02x "
 218 #endif
 219             "%-30s "
 220             "%04x %04x %04x %04x %04x %04x %04x %04x %04x %04x %04x ",
 221             R_CS, R_IP,
 222 #if BIG_DEBUG
 223             addr[0], addr[1], addr[2], addr[3], addr[4], addr[5],
 224 #endif
 225             buf,
 226             R_AX, R_BX, R_CX, R_DX, R_DI, R_SI, R_SP, R_BP, R_SS, R_DS, R_ES);
 227 #if 0
 228     fprintf(debugf, "%04x %04x %04x %04x ",
 229             ((u_short *)VECPTR(0x0D760FCA-14))[0],
 230             ((u_short *)VECPTR(0x0D760FCA-14))[1],
 231             ((u_short *)VECPTR(0x0D760F7A+8))[0],
 232             ((u_short *)VECPTR(0x0D760F7A+8))[1]);
 233 #endif
 234     showstate(R_EFLAGS, PSL_C, 'C');
 235     showstate(R_EFLAGS, PSL_PF, 'P');
 236     showstate(R_EFLAGS, PSL_AF, 'c');
 237     showstate(R_EFLAGS, PSL_Z, 'Z');
 238     showstate(R_EFLAGS, PSL_N, 'N');
 239     showstate(R_EFLAGS, PSL_T, 'T');
 240     showstate(R_EFLAGS, PSL_I, 'I');
 241     showstate(R_EFLAGS, PSL_D, 'D');
 242     showstate(R_EFLAGS, PSL_V, 'V');
 243     showstate(R_EFLAGS, PSL_NT, 'n');
 244     showstate(R_EFLAGS, PSL_RF, 'r');
 245     showstate(R_EFLAGS, PSL_VM, 'v');
 246     showstate(R_EFLAGS, PSL_AC, 'a');
 247     showstate(R_EFLAGS, PSL_VIF, 'i');
 248     showstate(R_EFLAGS, PSL_VIP, 'p');
 249     putc('\n', debugf);
 250 }