src/libcaptive/ps/signal.c

   1 /* $Id$
   2  * UNIX signal handling for processor emulation for support of ntoskrnl of libcaptive
   3  * Copyright (C) 2002 Jan Kratochvil <project-captive@jankratochvil.net>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; exactly version 2 of June 1991 is required
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  17  */
  18
  19
  20 #define _GNU_SOURCE 1   /* for sys/ucontext.h for REG_* */
  21
  22 #include "config.h"
  23
  24 #include "captive/signal.h"     /* self */
  25 #include <glib/gtypes.h>
  26 #include <glib/gmessages.h>
  27 #include <signal.h>
  28 #include "captive/macros.h"
  29 #include <sys/ucontext.h>       /* for struct ucontext */
  30 #include "captive/mm.h" /* for captive_mmap_map_get() */
  31 #include <sys/mman.h>
  32 #include "reactos/internal/mm.h"  /* for PAGE_SIZE */
  33 #include "captive/ldr.h"        /* for captive_ModuleList_patchpoint_find() */
  34 #include "captive/ldr_exports.h"        /* for struct captive_ModuleList_patchpoint */
  35
  36
  37 /**
  38  * _abnormal_termination:
  39  *
  40  * This call can be also accessed as AbnormalTermination() or abnormal_termination().
  41  *
  42  * Returns whether some exception occured (FIXME: in what scope?).
  43  * Exception handlers are registered from W32 binary in stack frames stored in "fs:[0x00000000]"
  44  * value which gets mapped by libcaptive/ps/signal.c to #fs_KPCR_ExceptionList
  45  * variable.
  46  *
  47  * libcaptive currently does not raise any exceptions therefore this call always returns value %0.
  48  * See RtlpDispatchException().
  49  *
  50  * Returns: non-zero if some exception is now registered and pending.
  51  */
  52 int _abnormal_termination(void)
  53 {
  54         return 0;
  55 }
  56
  57
  58 /**
  59  * RtlpDispatchException:
  60  * @ExceptionRecord: Ignored by libcaptive.
  61  * @Context: Ignored by libcaptive.
  62  *
  63  * Function definition to prevent inclusion of real RtlpDispatchException() implementation.
  64  * Currently libcaptive never raises any exception - fix _abnormal_termination() if it changes.
  65  *
  66  * Returns: Never returns. Value %0 if it returns although it is impossible.
  67  */
  68 ULONG RtlpDispatchException(IN PEXCEPTION_RECORD ExceptionRecord,IN PCONTEXT Context)
  69 {
  70         g_assert_not_reached();
  71         g_return_val_if_reached(0);
  72 }
  73
  74
  75 /* =='KeGetCurrentKPCR()->ExceptionList';
  76  * libcaptive has reduced KPCR (named 'captive_KPCR') which
  77  * does not contain this field
  78  */
  79 static greg_t fs_KPCR_ExceptionList=(greg_t)-1;
  80
  81 static gboolean instr_mov_greg_to_fsmem(int greg,const void *fsmem,struct ucontext *ucontext)
  82 {
  83         if (fsmem==(const void *)0x00000000) {  /* exception stack top pointer */
  84                 /* moving from %esp is required to pass! */
  85                 fs_KPCR_ExceptionList=ucontext->uc_mcontext.gregs[greg];
  86                 return TRUE;
  87                 }
  88         g_return_val_if_reached(FALSE);
  89 }
  90
  91 static gboolean instr_mov_fsmem_to_greg(const void *fsmem,int greg,struct ucontext *ucontext)
  92 {
  93         if (fsmem==(const void *)0x00000000) {  /* exception stack top pointer */
  94                 /* moving to %esp is required to pass! */
  95                 ucontext->uc_mcontext.gregs[greg]=fs_KPCR_ExceptionList;
  96                 return TRUE;
  97                 }
  98         if (fsmem==(const void *)0x00000124) {  /* =='KeGetCurrentKPCR()->CurrentThread' */
  99                 g_return_val_if_fail(greg!=REG_ESP,FALSE);
 100                 ucontext->uc_mcontext.gregs[greg]=(greg_t)captive_KeGetCurrentKPCR()->CurrentThread;
 101                 return TRUE;
 102                 }
 103         g_return_val_if_reached(FALSE);
 104 }
 105
 106 static int op_regcode_to_greg(guint8 regcode)
 107 {
 108         switch (regcode) {
 109                 case 0x00: return REG_EAX;
 110                 case 0x01: return REG_ECX;
 111                 case 0x02: return REG_EDX;
 112                 case 0x03: return REG_EBX;
 113                 case 0x04: return REG_ESP;
 114                 case 0x05: return REG_EBP;
 115                 case 0x06: return REG_ESI;
 116                 case 0x07: return REG_EDI;
 117                 }
 118         g_return_val_if_reached(REG_EAX);
 119 }
 120
 121 static void sigaction_SIGSEGV(int signo,siginfo_t *siginfo,struct ucontext *ucontext)
 122 {
 123 guint8 *reg_eip;
 124 const void *reg_eip_aligned;
 125
 126         g_return_if_fail(signo==SIGSEGV);
 127         g_return_if_fail(siginfo->si_signo==SIGSEGV);
 128         /* siginfo->si_code is weird, seen to have value 128 */
 129
 130         reg_eip=(void *)ucontext->uc_mcontext.gregs[REG_EIP];
 131
 132         /* 'reg_eip' is not yet PAGE_SIZE-aligned but we need the aligned ptr for captive_mmap_map_get().
 133          * glib NOTE: YOU MAY NOT STORE POINTERS IN INTEGERS.
 134          */
 135         reg_eip_aligned=(const void *)(((char *)reg_eip)-(GPOINTER_TO_UINT(reg_eip)&(PAGE_SIZE-1)));
 136         g_assert(reg_eip_aligned!=NULL);
 137         g_return_if_fail(!(captive_mmap_map_get(reg_eip_aligned)&PROT_EXEC));
 138
 139         /* all instruction notation comments are written in AT&T 'instr src,dest' syntax! */
 140         if (*reg_eip==0x64) {   /* prefix '%fs:' */
 141                 reg_eip++;
 142                 /* TODO:thread; %fs: is CPU-dependent */
 143                 if (*reg_eip==0xA3) {   /* 'mov %eax,%fs:{reg_eip[1..4]}' */
 144                         reg_eip++;
 145                         if (instr_mov_greg_to_fsmem(REG_EAX,*(const void **)reg_eip,ucontext)) {
 146                                 reg_eip+=4;
 147                                 goto ok;
 148                                 }
 149                         g_assert_not_reached();
 150                         }
 151                 if (*reg_eip==0x89) {   /* prefix 0x89 */
 152                         reg_eip++;
 153                         if ((*reg_eip & ~0x38)==0x05)   { /* 'mov %{op_regcode_to_greg(*reg_eip[b3..b5])},%fs:{reg_eip[1..4]} */
 154                                 reg_eip++;
 155                                 if (instr_mov_greg_to_fsmem(op_regcode_to_greg(reg_eip[-1]>>3U),*(const void **)reg_eip,ucontext)) {
 156                                         reg_eip+=4;
 157                                         goto ok;
 158                                         }
 159                                 g_assert_not_reached();
 160                                 }
 161                         g_assert_not_reached();
 162                         }
 163                 if (*reg_eip==0xA1) {   /* 'mov %fs:{reg_eip[1..4]},%eax' */
 164                         reg_eip++;
 165                         if (instr_mov_fsmem_to_greg(*(const void **)reg_eip,REG_EAX,ucontext)) {
 166                                 reg_eip+=4;
 167                                 goto ok;
 168                                 }
 169                         g_assert_not_reached();
 170                         }
 171                 if (*reg_eip==0x8B) {   /* prefix 0x8B */
 172                         reg_eip++;
 173                         if ((*reg_eip & ~0x38)==0x05) { /* 'mov %fs:{reg_eip[1..4]},%{op_regcode_to_greg(*reg_eip[b3..b5])} */
 174                                 reg_eip++;
 175                                 if (instr_mov_fsmem_to_greg(*(const void **)reg_eip,op_regcode_to_greg(reg_eip[-1]>>3U),ucontext)) {
 176                                         reg_eip+=4;
 177                                         goto ok;
 178                                         }
 179                                 g_assert_not_reached();
 180                                 }
 181                         g_assert_not_reached();
 182                         }
 183                 g_assert_not_reached();
 184                 }
 185
 186         if (*reg_eip==0xF4) {   /* hlt; from captive_ModuleList_patch() */
 187 struct captive_ModuleList_patchpoint *patchpoint;
 188 const gchar *funcname_disabled;
 189
 190                 g_log(G_LOG_DOMAIN,G_LOG_LEVEL_DEBUG,"%s: reg_eip=%p; 0xF4 hit",G_STRLOC,reg_eip);
 191
 192                 if ((funcname_disabled=captive_ModuleList_function_disable_find(
 193                                                 reg_eip)))      { /* ExportAddress */
 194                         g_error("%s: Reached disabled W32 function: %s",G_STRLOC,funcname_disabled);
 195                         g_assert_not_reached();
 196                         }
 197                 patchpoint=captive_ModuleList_patchpoint_find(
 198                                 reg_eip);       /* ExportAddress */
 199                 g_assert(patchpoint!=NULL);
 200                 if (reg_eip==patchpoint->orig_w32_func) {
 201                         g_assert(0xF4 /* hlt */ ==*patchpoint->orig_w32_func);
 202                         g_assert(patchpoint->orig_w32_2ndinstr_byte ==*patchpoint->orig_w32_2ndinstr);
 203                         if (patchpoint->through_w32_func) {
 204                                 *patchpoint->orig_w32_func=patchpoint->orig_w32_func_byte;
 205                                 *patchpoint->orig_w32_2ndinstr=0xF4;    /* hlt */
 206                                 }
 207                         else {  /* !patchpoint->through_w32_func */
 208                                 reg_eip=(guint8 *)patchpoint->wrap_wrap_func;
 209                                 }
 210                         goto ok;
 211                         }
 212                 if (reg_eip==patchpoint->orig_w32_2ndinstr) {
 213                         g_assert(patchpoint->orig_w32_func_byte ==*patchpoint->orig_w32_func);
 214                         g_assert(0xF4 /* hlt */ ==*patchpoint->orig_w32_2ndinstr);
 215                         g_assert(patchpoint->through_w32_func==TRUE);
 216                         *patchpoint->orig_w32_func=0xF4;        /* hlt */
 217                         *patchpoint->orig_w32_2ndinstr=patchpoint->orig_w32_2ndinstr_byte;
 218                         patchpoint->through_w32_func=FALSE;
 219                         goto ok;
 220                         }
 221                 g_assert_not_reached();
 222                 }
 223
 224         if (*reg_eip==0xFA) {   /* cli */
 225                 g_log(G_LOG_DOMAIN,G_LOG_LEVEL_DEBUG,"%s: reg_eip=%p; CLI neutralized",G_STRLOC,reg_eip);
 226                 *reg_eip=0x90;  /* nop */
 227                 goto ok;
 228                 }
 229
 230         g_assert_not_reached();
 231
 232 ok:
 233         ucontext->uc_mcontext.gregs[REG_EIP]=(greg_t)reg_eip;
 234         /* success */
 235 }
 236
 237 /**
 238  * captive_signal_init:
 239  *
 240  * Initialize UNIX signal handling to be able to emulate foreign W32
 241  * instructions. These instructions must be located inside address
 242  * space of foreign W32 binary code which is identified by successful
 243  * call to captive_mmap_map_get() returning #PROT_EXEC bit set.
 244  * This bit should be set from MmAllocateSection() called from
 245  * ntoskrnl/ldr/loader.c/LdrPEProcessModule().
 246  *
 247  * Currently emulated set is the access to %fs register offset %0
 248  * where the exception stack top pointer is located.
 249  *
 250  * Returns: %TRUE if successful.
 251  */
 252 gboolean captive_signal_init(void)
 253 {
 254 gint errint;
 255 struct sigaction sigaction_struct;
 256 sigset_t sigset;
 257
 258         CAPTIVE_MEMZERO(&sigaction_struct);     /* this structure may have unpredictable fields */
 259
 260         /* Init 'sigaction_struct.sa_mask'. */
 261         errint=sigemptyset(&sigaction_struct.sa_mask);
 262         g_return_val_if_fail(errint==0,FALSE);
 263         errint=sigaddset(&sigaction_struct.sa_mask,SIGSEGV);
 264         g_return_val_if_fail(errint==0,FALSE);
 265
 266         /* Set the signal sigaction handler. */
 267         sigaction_struct.sa_sigaction=(void (*)(int,siginfo_t *,void *))sigaction_SIGSEGV;
 268         sigaction_struct.sa_flags=0
 269                         |SA_SIGINFO;    /* Use 'sa_sigaction' (not 'sa_handler') */
 270         errint=sigaction(SIGSEGV,
 271                         &sigaction_struct,      /* act */
 272                         NULL);  /* oldact */
 273         g_return_val_if_fail(errint==0,FALSE);
 274
 275         /* Enable SIGSEGV signal (should be default). */
 276         errint=sigemptyset(&sigset);
 277         g_return_val_if_fail(errint==0,FALSE);
 278         errint=sigaddset(&sigset,SIGSEGV);
 279         g_return_val_if_fail(errint==0,FALSE);
 280         errint=sigprocmask(SIG_UNBLOCK,
 281                         &sigset,        /* set */
 282                         NULL);  /* oldset */
 283         g_return_val_if_fail(errint==0,FALSE);
 284
 285         return TRUE;
 286 }