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 int _abnormal_termination_orig(void);
  38 extern greg_t fs_KPCR_ExceptionList;
  39
  40 /**
  41  * _abnormal_termination_wrap:
  42  *
  43  * This call can be also accessed as AbnormalTermination() or _abnormal_termination().
  44  * It is a captive wrapper around _abnormal_termination() function.
  45  *
  46  * Returns whether some exception occured in the current #try block we are currently
  47  * #finish -ing. Any functions called from current #finish block will be considered
  48  * for returning zero back again. It is forbidden to call this function outside
  49  * of #finish block, result of such call is undefined.
  50  *
  51  * Exception handlers are registered from W32 binary in stack frames stored in "fs:[0x00000000]"
  52  * value which gets mapped by libcaptive/ps/signal.c to #fs_KPCR_ExceptionList
  53  * variable.
  54  *
  55  * If no exception handler was registered yet this function returns zero.
  56  *
  57  * See also RtlpDispatchException().
  58  *
  59  * Returns: non-zero if some exception is now being handled as pending.
  60  */
  61 int _abnormal_termination_wrap(void)
  62 {
  63         /* No handler registered yet? ntoskrnl _abnormal_termination() does not handle it
  64          * and I do not want to bother with registering toplevel handler.
  65          */
  66         if (fs_KPCR_ExceptionList==(greg_t)-1)
  67                 return 0;
  68
  69         return _abnormal_termination_orig();
  70 }
  71
  72
  73 #if 0
  74
  75 /**
  76  * RtlpDispatchException:
  77  * @ExceptionRecord: Ignored by libcaptive.
  78  * @Context: Ignored by libcaptive.
  79  *
  80  * Function definition to prevent inclusion of real RtlpDispatchException() implementation.
  81  * Currently libcaptive never raises any exception - fix _abnormal_termination() if it changes.
  82  *
  83  * Returns: Never returns. Value %0 if it returns although it is impossible.
  84  */
  85 ULONG RtlpDispatchException(IN PEXCEPTION_RECORD ExceptionRecord,IN PCONTEXT Context)
  86 {
  87         g_assert_not_reached();
  88         g_return_val_if_reached(0);
  89 }
  90
  91 #endif
  92
  93
  94 /* =='KeGetCurrentKPCR()->ExceptionList';
  95  * libcaptive has reduced KPCR (named 'captive_KPCR') which
  96  * does not contain this field
  97  */
  98 greg_t fs_KPCR_ExceptionList=(greg_t)-1;
  99
 100 /* FIXME */
 101 static greg_t fs_KPCR_Unknown638=0;
 102
 103
 104 static gboolean instr_mov_greg_to_fsmem(int greg,const void *fsmem,struct ucontext *ucontext)
 105 {
 106         if (fsmem==(const void *)0x00000000) {  /* exception stack top pointer */
 107                 /* moving from %esp is required to pass! */
 108                 fs_KPCR_ExceptionList=ucontext->uc_mcontext.gregs[greg];
 109                 return TRUE;
 110                 }
 111         g_return_val_if_reached(FALSE);
 112 }
 113
 114 static gboolean instr_mov_immed_to_fsmem(greg_t immed,const void *fsmem,struct ucontext *ucontext)
 115 {
 116         if (fsmem==(const void *)0x00000000) {  /* exception stack top pointer */
 117                 fs_KPCR_ExceptionList=immed;
 118                 return TRUE;
 119                 }
 120         g_return_val_if_reached(FALSE);
 121 }
 122
 123 static gboolean instr_mov_fsmem_to_greg(const void *fsmem,int greg,struct ucontext *ucontext)
 124 {
 125         if (fsmem==(const void *)0x00000000) {  /* exception stack top pointer */
 126                 /* moving to %esp is required to pass! */
 127                 ucontext->uc_mcontext.gregs[greg]=fs_KPCR_ExceptionList;
 128                 return TRUE;
 129                 }
 130         if (fsmem==(const void *)0x00000051) {  /* =='KeGetCurrentKPCR()->Number' */
 131                 g_return_val_if_fail(greg!=REG_ESP,FALSE);
 132                 ucontext->uc_mcontext.gregs[greg]=(greg_t)0;    /* ==libcaptive version of KeGetCurrentProcessorNumber() */
 133                 return TRUE;
 134                 }
 135         if (fsmem==(const void *)0x00000124) {  /* =='KeGetCurrentKPCR()->CurrentThread' */
 136                 g_return_val_if_fail(greg!=REG_ESP,FALSE);
 137                 ucontext->uc_mcontext.gregs[greg]=(greg_t)captive_KeGetCurrentKPCR()->CurrentThread;
 138                 return TRUE;
 139                 }
 140         g_return_val_if_reached(FALSE);
 141 }
 142
 143 static gboolean instr_push_fsmem(const void *fsmem,struct ucontext *ucontext)
 144 {
 145         if (fsmem==(const void *)0x00000000) {  /* exception stack top pointer */
 146                 ucontext->uc_mcontext.gregs[REG_ESP]-=4;
 147                 *(greg_t *)ucontext->uc_mcontext.gregs[REG_ESP]=fs_KPCR_ExceptionList;
 148                 return TRUE;
 149                 }
 150         g_return_val_if_reached(FALSE);
 151 }
 152
 153 static gboolean instr_pop_fsmem(const void *fsmem,struct ucontext *ucontext)
 154 {
 155         if (fsmem==(const void *)0x00000000) {  /* exception stack top pointer */
 156                 fs_KPCR_ExceptionList=*(greg_t *)ucontext->uc_mcontext.gregs[REG_ESP];
 157                 ucontext->uc_mcontext.gregs[REG_ESP]+=4;
 158                 return TRUE;
 159                 }
 160         g_return_val_if_reached(FALSE);
 161 }
 162
 163 static gboolean instr_incl_fsmem(const void *fsmem,struct ucontext *ucontext)
 164 {
 165         if (fsmem==(const void *)0x00000638) {  /* Unknown638 */
 166                 fs_KPCR_Unknown638++;
 167                 return TRUE;
 168                 }
 169         g_return_val_if_reached(FALSE);
 170 }
 171
 172 static int op_regcode_to_greg(guint8 regcode)
 173 {
 174         switch (regcode) {
 175                 case 0x00: return REG_EAX;
 176                 case 0x01: return REG_ECX;
 177                 case 0x02: return REG_EDX;
 178                 case 0x03: return REG_EBX;
 179                 case 0x04: return REG_ESP;
 180                 case 0x05: return REG_EBP;
 181                 case 0x06: return REG_ESI;
 182                 case 0x07: return REG_EDI;
 183                 }
 184         g_return_val_if_reached(REG_EAX);
 185 }
 186
 187 static void sigaction_SIGSEGV(int signo,siginfo_t *siginfo,struct ucontext *ucontext)
 188 {
 189 guint8 *reg_eip;
 190 const void *reg_eip_aligned;
 191 static const void *reg_eip_aligned_last_valid=NULL;     /* performance cache */
 192
 193         g_return_if_fail(signo==SIGSEGV);
 194         g_return_if_fail(siginfo->si_signo==SIGSEGV);
 195         /* siginfo->si_code is weird, seen to have value 128 */
 196
 197         reg_eip=(void *)ucontext->uc_mcontext.gregs[REG_EIP];
 198
 199         /* 'reg_eip' is not yet PAGE_SIZE-aligned but we need the aligned ptr for captive_mmap_map_get().
 200          * glib NOTE: YOU MAY NOT STORE POINTERS IN INTEGERS.
 201          */
 202         reg_eip_aligned=(const void *)(((char *)reg_eip)-(GPOINTER_TO_UINT(reg_eip)&(PAGE_SIZE-1)));
 203         g_assert(reg_eip_aligned!=NULL);
 204
 205         /* We do not expect any pages can get un-PROT_EXEC-ed
 206          * and therefore we never invalidate our cache 'reg_eip_aligned_last_valid'.
 207          */
 208         if (reg_eip_aligned_last_valid!=reg_eip_aligned) {
 209                 g_return_if_fail(!(captive_mmap_map_get(reg_eip_aligned)&PROT_EXEC));
 210                 reg_eip_aligned_last_valid=reg_eip_aligned;
 211                 }
 212
 213         /* all instruction notation comments are written in AT&T 'instr src,dest' syntax! */
 214         if (*reg_eip==0x64) {   /* prefix '%fs:' */
 215                 reg_eip++;
 216                 /* TODO:thread; %fs: is CPU-dependent */
 217                 if (*reg_eip==0x0F) {   /* two-byte opcode */
 218                         reg_eip++;
 219                         if (*reg_eip==0xB6) {   /* ??? */
 220                                 reg_eip++;
 221                                 if (*reg_eip==0x05) {   /* movzbl %fs:{reg_eip[1..4]},%eax */
 222                                         reg_eip++;
 223                                         if (instr_mov_fsmem_to_greg(*(const void **)reg_eip,REG_EAX,ucontext)) {
 224                                                 reg_eip+=4;
 225                                                 goto ok;
 226                                                 }
 227                                         g_assert_not_reached();
 228                                         }
 229                                 g_assert_not_reached();
 230                                 }
 231                         g_assert_not_reached();
 232                         }
 233                 if (*reg_eip==0xA3) {   /* 'mov %eax,%fs:{reg_eip[1..4]}' */
 234                         reg_eip++;
 235                         if (instr_mov_greg_to_fsmem(REG_EAX,*(const void **)reg_eip,ucontext)) {
 236                                 reg_eip+=4;
 237                                 goto ok;
 238                                 }
 239                         g_assert_not_reached();
 240                         }
 241                 if (*reg_eip==0x89) {   /* prefix 0x89 */
 242                         reg_eip++;
 243                         if ((*reg_eip & ~0x38)==0x05)   { /* 'mov %{op_regcode_to_greg(*reg_eip[b3..b5])},%fs:{reg_eip[1..4]} */
 244                                 reg_eip++;
 245                                 if (instr_mov_greg_to_fsmem(op_regcode_to_greg(reg_eip[-1]>>3U),*(const void **)reg_eip,ucontext)) {
 246                                         reg_eip+=4;
 247                                         goto ok;
 248                                         }
 249                                 g_assert_not_reached();
 250                                 }
 251                         g_assert_not_reached();
 252                         }
 253                 if (*reg_eip==0xA1) {   /* 'mov %fs:{reg_eip[1..4]},%eax' */
 254                         reg_eip++;
 255                         if (instr_mov_fsmem_to_greg(*(const void **)reg_eip,REG_EAX,ucontext)) {
 256                                 reg_eip+=4;
 257                                 goto ok;
 258                                 }
 259                         g_assert_not_reached();
 260                         }
 261                 if (*reg_eip==0x8B) {   /* prefix 0x8B */
 262                         reg_eip++;
 263                         if ((*reg_eip & ~0x38)==0x05) { /* 'mov %fs:{reg_eip[1..4]},%{op_regcode_to_greg(*reg_eip[b3..b5])}' */
 264                                 reg_eip++;
 265                                 if (instr_mov_fsmem_to_greg(*(const void **)reg_eip,op_regcode_to_greg(reg_eip[-1]>>3U),ucontext)) {
 266                                         reg_eip+=4;
 267                                         goto ok;
 268                                         }
 269                                 g_assert_not_reached();
 270                                 }
 271                         g_assert_not_reached();
 272                         }
 273                 if (*reg_eip==0xFF) {   /* prefix 0xFF */
 274                         reg_eip++;
 275                         if (*reg_eip==0x05) {   /* 'incl %fs:{reg_eip[1..4]}' */
 276                                 reg_eip++;
 277                                 if (instr_incl_fsmem(*(const void **)reg_eip,ucontext)) {
 278                                         reg_eip+=4;
 279                                         goto ok;
 280                                         }
 281                                 g_assert_not_reached();
 282                                 }
 283                         if (*reg_eip==0x35) {   /* 'pushl %fs:{reg_eip[1..4]}' */
 284                                 reg_eip++;
 285                                 if (instr_push_fsmem(*(const void **)reg_eip,ucontext)) {
 286                                         reg_eip+=4;
 287                                         goto ok;
 288                                         }
 289                                 g_assert_not_reached();
 290                                 }
 291                         g_assert_not_reached();
 292                         }
 293                 if (*reg_eip==0x8F) {   /* prefix 0x0F */
 294                         reg_eip++;
 295                         if (*reg_eip==0x05) {   /* 'popl %fs:{reg_eip[1..4]}' */
 296                                 reg_eip++;
 297                                 if (instr_pop_fsmem(*(const void **)reg_eip,ucontext)) {
 298                                         reg_eip+=4;
 299                                         goto ok;
 300                                         }
 301                                 g_assert_not_reached();
 302                                 }
 303                         g_assert_not_reached();
 304                         }
 305                 if (*reg_eip==0xC7) {   /* prefix 0xC7 */
 306                         reg_eip++;
 307                         if (*reg_eip==0x05) {   /* 'movl ${reg_eip[5..8]},%fs:{reg_eip[1..4]}' */
 308                                 reg_eip++;
 309                                 if (instr_mov_immed_to_fsmem(((greg_t *)reg_eip)[1],*(const void **)reg_eip,ucontext)) {
 310                                         reg_eip+=4+4;
 311                                         goto ok;
 312                                         }
 313                                 g_assert_not_reached();
 314                                 }
 315                         g_assert_not_reached();
 316                         }
 317                 g_assert_not_reached();
 318                 }
 319
 320         /* all instruction notation comments are written in AT&T 'instr src,dest' syntax! */
 321         if (*reg_eip==0x66) {   /* prefix '%fs:' */
 322                 reg_eip++;
 323                 /* TODO:thread; %fs: is CPU-dependent */
 324                 if (*reg_eip==0x8E) {   /* two-byte opcode */
 325                         reg_eip++;
 326                         if (*reg_eip==0xE3) {   /* 'mov %bx,%fs' */
 327                                 reg_eip++;
 328                                 g_assert(0x30==(0xFFFF&ucontext->uc_mcontext.gregs[REG_EBX]));
 329                                 /* 'reload' of %fs can be ignored */
 330                                 goto ok;
 331                                 }
 332                         g_assert_not_reached();
 333                         }
 334                 g_assert_not_reached();
 335                 }
 336
 337         if (*reg_eip==0xF4) {   /* hlt; from captive_ModuleList_patch() */
 338 struct captive_ModuleList_patchpoint *patchpoint;
 339 const gchar *funcname_disabled;
 340
 341                 g_log(G_LOG_DOMAIN,G_LOG_LEVEL_DEBUG,"%s: reg_eip=%p; 0xF4 hit",G_STRLOC,reg_eip);
 342
 343                 if ((funcname_disabled=captive_ModuleList_function_disable_find(
 344                                                 reg_eip)))      { /* ExportAddress */
 345                         g_error("%s: Reached disabled W32 function: %s",G_STRLOC,funcname_disabled);
 346                         g_assert_not_reached();
 347                         }
 348                 patchpoint=captive_ModuleList_patchpoint_find(
 349                                 reg_eip);       /* ExportAddress */
 350                 g_assert(patchpoint!=NULL);
 351                 if (reg_eip==patchpoint->orig_w32_func) {
 352                         g_assert(0xF4 /* hlt */ ==*patchpoint->orig_w32_func);
 353                         g_assert(patchpoint->orig_w32_2ndinstr_byte ==*patchpoint->orig_w32_2ndinstr);
 354                         if (patchpoint->through_w32_func) {
 355                                 *patchpoint->orig_w32_func=patchpoint->orig_w32_func_byte;
 356                                 *patchpoint->orig_w32_2ndinstr=0xF4;    /* hlt */
 357                                 }
 358                         else {  /* !patchpoint->through_w32_func */
 359                                 reg_eip=(guint8 *)patchpoint->wrap_wrap_func;
 360                                 }
 361                         goto ok;
 362                         }
 363                 if (reg_eip==patchpoint->orig_w32_2ndinstr) {
 364                         g_assert(patchpoint->orig_w32_func_byte ==*patchpoint->orig_w32_func);
 365                         g_assert(0xF4 /* hlt */ ==*patchpoint->orig_w32_2ndinstr);
 366                         g_assert(patchpoint->through_w32_func==TRUE);
 367                         *patchpoint->orig_w32_func=0xF4;        /* hlt */
 368                         *patchpoint->orig_w32_2ndinstr=patchpoint->orig_w32_2ndinstr_byte;
 369                         patchpoint->through_w32_func=FALSE;
 370                         goto ok;
 371                         }
 372                 g_assert_not_reached();
 373                 }
 374
 375         if (*reg_eip==0xFA) {   /* cli */
 376                 g_log(G_LOG_DOMAIN,G_LOG_LEVEL_DEBUG,"%s: reg_eip=%p; CLI neutralized",G_STRLOC,reg_eip);
 377                 *reg_eip=0x90;  /* nop */
 378                 goto ok;
 379                 }
 380
 381         if (*reg_eip==0xFB) {   /* sti */
 382                 g_log(G_LOG_DOMAIN,G_LOG_LEVEL_DEBUG,"%s: reg_eip=%p; STI neutralized",G_STRLOC,reg_eip);
 383                 *reg_eip=0x90;  /* nop */
 384                 goto ok;
 385                 }
 386
 387         g_assert_not_reached();
 388
 389 ok:
 390         ucontext->uc_mcontext.gregs[REG_EIP]=(greg_t)reg_eip;
 391         /* success */
 392 }
 393
 394 /**
 395  * captive_signal_init:
 396  *
 397  * Initialize UNIX signal handling to be able to emulate foreign W32
 398  * instructions. These instructions must be located inside address
 399  * space of foreign W32 binary code which is identified by successful
 400  * call to captive_mmap_map_get() returning #PROT_EXEC bit set.
 401  * This bit should be set from MmAllocateSection() called from
 402  * ntoskrnl/ldr/loader.c/LdrPEProcessModule().
 403  *
 404  * Currently emulated set is the access to %fs register offset %0
 405  * where the exception stack top pointer is located.
 406  *
 407  * Returns: %TRUE if successful.
 408  */
 409 gboolean captive_signal_init(void)
 410 {
 411 gint errint;
 412 struct sigaction sigaction_struct;
 413 sigset_t sigset;
 414
 415         CAPTIVE_MEMZERO(&sigaction_struct);     /* this structure may have unpredictable fields */
 416
 417         /* Init 'sigaction_struct.sa_mask'. */
 418         errint=sigemptyset(&sigaction_struct.sa_mask);
 419         g_return_val_if_fail(errint==0,FALSE);
 420         errint=sigaddset(&sigaction_struct.sa_mask,SIGSEGV);
 421         g_return_val_if_fail(errint==0,FALSE);
 422
 423         /* Set the signal sigaction handler. */
 424         sigaction_struct.sa_sigaction=(void (*)(int,siginfo_t *,void *))sigaction_SIGSEGV;
 425         sigaction_struct.sa_flags=0
 426                         |SA_SIGINFO;    /* Use 'sa_sigaction' (not 'sa_handler') */
 427         errint=sigaction(SIGSEGV,
 428                         &sigaction_struct,      /* act */
 429                         NULL);  /* oldact */
 430         g_return_val_if_fail(errint==0,FALSE);
 431
 432         /* Enable SIGSEGV signal (should be default). */
 433         errint=sigemptyset(&sigset);
 434         g_return_val_if_fail(errint==0,FALSE);
 435         errint=sigaddset(&sigset,SIGSEGV);
 436         g_return_val_if_fail(errint==0,FALSE);
 437         errint=sigprocmask(SIG_UNBLOCK,
 438                         &sigset,        /* set */
 439                         NULL);  /* oldset */
 440         g_return_val_if_fail(errint==0,FALSE);
 441
 442         return TRUE;
 443 }