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