server/ptrace.c

   1 /*
   2  * Server-side ptrace support
   3  *
   4  * Copyright (C) 1999 Alexandre Julliard
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  19  */
  20
  21 #include "config.h"
  22 #include "wine/port.h"
  23
  24 #include <assert.h>
  25 #include <errno.h>
  26 #include <fcntl.h>
  27 #include <stdio.h>
  28 #include <signal.h>
  29 #include <stdarg.h>
  30 #include <sys/types.h>
  31 #ifdef HAVE_SYS_PTRACE_H
  32 # include <sys/ptrace.h>
  33 #endif
  34 #ifdef HAVE_SYS_PARAM_H
  35 # include <sys/param.h>
  36 #endif
  37 #ifdef HAVE_SYS_WAIT_H
  38 # include <sys/wait.h>
  39 #endif
  40 #ifdef HAVE_SYS_SYSCALL_H
  41 # include <sys/syscall.h>
  42 #endif
  43 #ifdef HAVE_SYS_UCONTEXT_H
  44 # include <sys/ucontext.h>
  45 #endif
  46 #ifdef HAVE_SYS_THR_H
  47 # include <sys/thr.h>
  48 #endif
  49 #include <unistd.h>
  50
  51 #include "ntstatus.h"
  52 #define WIN32_NO_STATUS
  53 #include "winternl.h"
  54
  55 #include "file.h"
  56 #include "process.h"
  57 #include "thread.h"
  58
  59 #ifdef USE_PTRACE
  60
  61 #ifndef PTRACE_CONT
  62 #define PTRACE_CONT PT_CONTINUE
  63 #endif
  64 #ifndef PTRACE_SINGLESTEP
  65 #define PTRACE_SINGLESTEP PT_STEP
  66 #endif
  67 #ifndef PTRACE_ATTACH
  68 #define PTRACE_ATTACH PT_ATTACH
  69 #endif
  70 #ifndef PTRACE_DETACH
  71 #define PTRACE_DETACH PT_DETACH
  72 #endif
  73 #ifndef PTRACE_PEEKDATA
  74 #define PTRACE_PEEKDATA PT_READ_D
  75 #endif
  76 #ifndef PTRACE_POKEDATA
  77 #define PTRACE_POKEDATA PT_WRITE_D
  78 #endif
  79 #ifndef PTRACE_PEEKUSER
  80 #define PTRACE_PEEKUSER PT_READ_U
  81 #endif
  82 #ifndef PTRACE_POKEUSER
  83 #define PTRACE_POKEUSER PT_WRITE_U
  84 #endif
  85
  86 #ifdef PT_GETDBREGS
  87 #define PTRACE_GETDBREGS PT_GETDBREGS
  88 #endif
  89 #ifdef PT_SETDBREGS
  90 #define PTRACE_SETDBREGS PT_SETDBREGS
  91 #endif
  92
  93 #ifndef HAVE_SYS_PTRACE_H
  94 #define PT_CONTINUE 0
  95 #define PT_ATTACH   1
  96 #define PT_DETACH   2
  97 #define PT_READ_D   3
  98 #define PT_WRITE_D  4
  99 #define PT_STEP     5
 100 static inline int ptrace(int req, ...) { errno = EPERM; return -1; /*FAIL*/ }
 101 #endif  /* HAVE_SYS_PTRACE_H */
 102
 103 #ifndef __WALL
 104 #define __WALL 0
 105 #endif
 106
 107 /* handle a status returned by waitpid */
 108 static int handle_child_status( struct thread *thread, int pid, int status, int want_sig )
 109 {
 110     if (WIFSTOPPED(status))
 111     {
 112         int sig = WSTOPSIG(status);
 113         if (debug_level && thread)
 114             fprintf( stderr, "%04x: *signal* signal=%d\n", thread->id, sig );
 115         if (sig != want_sig)
 116         {
 117             /* ignore other signals for now */
 118             ptrace( PTRACE_CONT, pid, (caddr_t)1, sig );
 119         }
 120         return sig;
 121     }
 122     if (thread && (WIFSIGNALED(status) || WIFEXITED(status)))
 123     {
 124         thread->unix_pid = -1;
 125         thread->unix_tid = -1;
 126         if (debug_level)
 127         {
 128             if (WIFSIGNALED(status))
 129                 fprintf( stderr, "%04x: *exited* signal=%d\n",
 130                          thread->id, WTERMSIG(status) );
 131             else
 132                 fprintf( stderr, "%04x: *exited* status=%d\n",
 133                          thread->id, WEXITSTATUS(status) );
 134         }
 135     }
 136     return 0;
 137 }
 138
 139 /* handle a SIGCHLD signal */
 140 void sigchld_callback(void)
 141 {
 142     int pid, status;
 143
 144     for (;;)
 145     {
 146         if (!(pid = waitpid( -1, &status, WUNTRACED | WNOHANG | __WALL ))) break;
 147         if (pid != -1)
 148         {
 149             struct thread *thread = get_thread_from_tid( pid );
 150             if (!thread) thread = get_thread_from_pid( pid );
 151             handle_child_status( thread, pid, status, -1 );
 152         }
 153         else break;
 154     }
 155 }
 156
 157 /* return the Unix pid to use in ptrace calls for a given process */
 158 static int get_ptrace_pid( struct thread *thread )
 159 {
 160 #ifdef linux  /* linux always uses thread id */
 161     if (thread->unix_tid != -1) return thread->unix_tid;
 162 #endif
 163     return thread->unix_pid;
 164 }
 165
 166 /* return the Unix tid to use in ptrace calls for a given thread */
 167 static int get_ptrace_tid( struct thread *thread )
 168 {
 169     if (thread->unix_tid != -1) return thread->unix_tid;
 170     return thread->unix_pid;
 171 }
 172
 173 /* wait for a ptraced child to get a certain signal */
 174 static int waitpid_thread( struct thread *thread, int signal )
 175 {
 176     int res, status;
 177
 178     start_watchdog();
 179     for (;;)
 180     {
 181         if ((res = waitpid( get_ptrace_pid(thread), &status, WUNTRACED | __WALL )) == -1)
 182         {
 183             if (errno == EINTR)
 184             {
 185                 if (!watchdog_triggered()) continue;
 186                 if (debug_level) fprintf( stderr, "%04x: *watchdog* waitpid aborted\n", thread->id );
 187             }
 188             else if (errno == ECHILD)  /* must have died */
 189             {
 190                 thread->unix_pid = -1;
 191                 thread->unix_tid = -1;
 192             }
 193             else perror( "waitpid" );
 194             stop_watchdog();
 195             return 0;
 196         }
 197         res = handle_child_status( thread, res, status, signal );
 198         if (!res || res == signal) break;
 199     }
 200     stop_watchdog();
 201     return (thread->unix_pid != -1);
 202 }
 203
 204 /* send a signal to a specific thread */
 205 static inline int tkill( int tgid, int pid, int sig )
 206 {
 207 #ifdef __linux__
 208     int ret = syscall( __NR_tgkill, tgid, pid, sig );
 209     if (ret < 0 && errno == ENOSYS) ret = syscall( __NR_tkill, pid, sig );
 210     return ret;
 211 #elif (defined(__FreeBSD__) || defined (__FreeBSD_kernel__)) && defined(HAVE_THR_KILL2)
 212     return thr_kill2( tgid, pid, sig );
 213 #else
 214     errno = ENOSYS;
 215     return -1;
 216 #endif
 217 }
 218
 219 /* initialize the process tracing mechanism */
 220 void init_tracing_mechanism(void)
 221 {
 222     /* no initialization needed for ptrace */
 223 }
 224
 225 /* initialize the per-process tracing mechanism */
 226 void init_process_tracing( struct process *process )
 227 {
 228     /* ptrace setup is done on-demand */
 229 }
 230
 231 /* terminate the per-process tracing mechanism */
 232 void finish_process_tracing( struct process *process )
 233 {
 234 }
 235
 236 /* send a Unix signal to a specific thread */
 237 int send_thread_signal( struct thread *thread, int sig )
 238 {
 239     int ret = -1;
 240
 241     if (thread->unix_pid != -1)
 242     {
 243         if (thread->unix_tid != -1)
 244         {
 245             ret = tkill( thread->unix_pid, thread->unix_tid, sig );
 246             if (ret == -1 && errno == ENOSYS) ret = kill( thread->unix_pid, sig );
 247         }
 248         else ret = kill( thread->unix_pid, sig );
 249
 250         if (ret == -1 && errno == ESRCH) /* thread got killed */
 251         {
 252             thread->unix_pid = -1;
 253             thread->unix_tid = -1;
 254         }
 255     }
 256     if (debug_level && ret != -1)
 257         fprintf( stderr, "%04x: *sent signal* signal=%d\n", thread->id, sig );
 258     return (ret != -1);
 259 }
 260
 261 /* resume a thread after we have used ptrace on it */
 262 static void resume_after_ptrace( struct thread *thread )
 263 {
 264     if (thread->unix_pid == -1) return;
 265     if (ptrace( PTRACE_DETACH, get_ptrace_pid(thread), (caddr_t)1, 0 ) == -1)
 266     {
 267         if (errno == ESRCH) thread->unix_pid = thread->unix_tid = -1;  /* thread got killed */
 268     }
 269 }
 270
 271 /* suspend a thread to allow using ptrace on it */
 272 /* you must do a resume_after_ptrace when finished with the thread */
 273 static int suspend_for_ptrace( struct thread *thread )
 274 {
 275     /* can't stop a thread while initialisation is in progress */
 276     if (thread->unix_pid == -1 || !is_process_init_done(thread->process)) goto error;
 277
 278     /* this may fail if the client is already being debugged */
 279     if (ptrace( PTRACE_ATTACH, get_ptrace_pid(thread), 0, 0 ) == -1)
 280     {
 281         if (errno == ESRCH) thread->unix_pid = thread->unix_tid = -1;  /* thread got killed */
 282         goto error;
 283     }
 284     if (waitpid_thread( thread, SIGSTOP )) return 1;
 285     resume_after_ptrace( thread );
 286  error:
 287     set_error( STATUS_ACCESS_DENIED );
 288     return 0;
 289 }
 290
 291 /* read a long from a thread address space */
 292 static long read_thread_long( struct thread *thread, long *addr, long *data )
 293 {
 294     errno = 0;
 295     *data = ptrace( PTRACE_PEEKDATA, get_ptrace_pid(thread), (caddr_t)addr, 0 );
 296     if ( *data == -1 && errno)
 297     {
 298         file_set_error();
 299         return -1;
 300     }
 301     return 0;
 302 }
 303
 304 /* write a long to a thread address space */
 305 static long write_thread_long( struct thread *thread, long *addr, long data, unsigned long mask )
 306 {
 307     long res;
 308     if (mask != ~0ul)
 309     {
 310         if (read_thread_long( thread, addr, &res ) == -1) return -1;
 311         data = (data & mask) | (res & ~mask);
 312     }
 313     if ((res = ptrace( PTRACE_POKEDATA, get_ptrace_pid(thread), (caddr_t)addr, data )) == -1)
 314         file_set_error();
 315     return res;
 316 }
 317
 318 /* return a thread of the process suitable for ptracing */
 319 static struct thread *get_ptrace_thread( struct process *process )
 320 {
 321     struct thread *thread;
 322
 323     LIST_FOR_EACH_ENTRY( thread, &process->thread_list, struct thread, proc_entry )
 324     {
 325         if (thread->unix_pid != -1) return thread;
 326     }
 327     set_error( STATUS_PROCESS_IS_TERMINATING );  /* process is dead */
 328     return NULL;
 329 }
 330
 331 /* read data from a process memory space */
 332 int read_process_memory( struct process *process, client_ptr_t ptr, data_size_t size, char *dest )
 333 {
 334     struct thread *thread = get_ptrace_thread( process );
 335     unsigned int first_offset, last_offset, len;
 336     long data, *addr;
 337
 338     if (!thread) return 0;
 339
 340     if ((unsigned long)ptr != ptr)
 341     {
 342         set_error( STATUS_ACCESS_DENIED );
 343         return 0;
 344     }
 345
 346     first_offset = ptr % sizeof(long);
 347     last_offset = (size + first_offset) % sizeof(long);
 348     if (!last_offset) last_offset = sizeof(long);
 349
 350     addr = (long *)(unsigned long)(ptr - first_offset);
 351     len = (size + first_offset + sizeof(long) - 1) / sizeof(long);
 352
 353     if (suspend_for_ptrace( thread ))
 354     {
 355         if (len > 3)  /* /proc/pid/mem should be faster for large sizes */
 356         {
 357             char procmem[24];
 358             int fd;
 359
 360             sprintf( procmem, "/proc/%u/mem", process->unix_pid );
 361             if ((fd = open( procmem, O_RDONLY )) != -1)
 362             {
 363                 ssize_t ret = pread( fd, dest, size, ptr );
 364                 close( fd );
 365                 if (ret == size)
 366                 {
 367                     len = 0;
 368                     goto done;
 369                 }
 370             }
 371         }
 372
 373         if (len > 1)
 374         {
 375             if (read_thread_long( thread, addr++, &data ) == -1) goto done;
 376             memcpy( dest, (char *)&data + first_offset, sizeof(long) - first_offset );
 377             dest += sizeof(long) - first_offset;
 378             first_offset = 0;
 379             len--;
 380         }
 381
 382         while (len > 1)
 383         {
 384             if (read_thread_long( thread, addr++, &data ) == -1) goto done;
 385             memcpy( dest, &data, sizeof(long) );
 386             dest += sizeof(long);
 387             len--;
 388         }
 389
 390         if (read_thread_long( thread, addr++, &data ) == -1) goto done;
 391         memcpy( dest, (char *)&data + first_offset, last_offset - first_offset );
 392         len--;
 393
 394     done:
 395         resume_after_ptrace( thread );
 396     }
 397     return !len;
 398 }
 399
 400 /* make sure we can write to the whole address range */
 401 /* len is the total size (in ints) */
 402 static int check_process_write_access( struct thread *thread, long *addr, data_size_t len )
 403 {
 404     int page = get_page_size() / sizeof(int);
 405
 406     for (;;)
 407     {
 408         if (write_thread_long( thread, addr, 0, 0 ) == -1) return 0;
 409         if (len <= page) break;
 410         addr += page;
 411         len -= page;
 412     }
 413     return (write_thread_long( thread, addr + len - 1, 0, 0 ) != -1);
 414 }
 415
 416 /* write data to a process memory space */
 417 int write_process_memory( struct process *process, client_ptr_t ptr, data_size_t size, const char *src )
 418 {
 419     struct thread *thread = get_ptrace_thread( process );
 420     int ret = 0;
 421     long data = 0;
 422     data_size_t len;
 423     long *addr;
 424     unsigned long first_mask, first_offset, last_mask, last_offset;
 425
 426     if (!thread) return 0;
 427
 428     if ((unsigned long)ptr != ptr)
 429     {
 430         set_error( STATUS_ACCESS_DENIED );
 431         return 0;
 432     }
 433
 434     /* compute the mask for the first long */
 435     first_mask = ~0;
 436     first_offset = ptr % sizeof(long);
 437     memset( &first_mask, 0, first_offset );
 438
 439     /* compute the mask for the last long */
 440     last_offset = (size + first_offset) % sizeof(long);
 441     if (!last_offset) last_offset = sizeof(long);
 442     last_mask = 0;
 443     memset( &last_mask, 0xff, last_offset );
 444
 445     addr = (long *)(unsigned long)(ptr - first_offset);
 446     len = (size + first_offset + sizeof(long) - 1) / sizeof(long);
 447
 448     if (suspend_for_ptrace( thread ))
 449     {
 450         if (!check_process_write_access( thread, addr, len ))
 451         {
 452             set_error( STATUS_ACCESS_DENIED );
 453             goto done;
 454         }
 455
 456         if (len > 3)
 457         {
 458             char procmem[24];
 459             int fd;
 460
 461             sprintf( procmem, "/proc/%u/mem", process->unix_pid );
 462             if ((fd = open( procmem, O_WRONLY )) != -1)
 463             {
 464                 ssize_t r = pwrite( fd, src, size, ptr );
 465                 close( fd );
 466                 if (r == size)
 467                 {
 468                     ret = 1;
 469                     goto done;
 470                 }
 471             }
 472         }
 473
 474         /* first word is special */
 475         if (len > 1)
 476         {
 477             memcpy( (char *)&data + first_offset, src, sizeof(long) - first_offset );
 478             src += sizeof(long) - first_offset;
 479             if (write_thread_long( thread, addr++, data, first_mask ) == -1) goto done;
 480             first_offset = 0;
 481             len--;
 482         }
 483         else last_mask &= first_mask;
 484
 485         while (len > 1)
 486         {
 487             memcpy( &data, src, sizeof(long) );
 488             src += sizeof(long);
 489             if (write_thread_long( thread, addr++, data, ~0ul ) == -1) goto done;
 490             len--;
 491         }
 492
 493         /* last word is special too */
 494         memcpy( (char *)&data + first_offset, src, last_offset - first_offset );
 495         if (write_thread_long( thread, addr, data, last_mask ) == -1) goto done;
 496         ret = 1;
 497
 498     done:
 499         resume_after_ptrace( thread );
 500     }
 501     return ret;
 502 }
 503
 504 /* retrieve an LDT selector entry */
 505 void get_selector_entry( struct thread *thread, int entry, unsigned int *base,
 506                          unsigned int *limit, unsigned char *flags )
 507 {
 508     if (!thread->process->ldt_copy)
 509     {
 510         set_error( STATUS_ACCESS_DENIED );
 511         return;
 512     }
 513     if (entry >= 8192)
 514     {
 515         set_error( STATUS_ACCESS_VIOLATION );
 516         return;
 517     }
 518     if (suspend_for_ptrace( thread ))
 519     {
 520         unsigned char flags_buf[sizeof(long)];
 521         long *addr = (long *)(unsigned long)thread->process->ldt_copy + entry;
 522         if (read_thread_long( thread, addr, (long *)base ) == -1) goto done;
 523         if (read_thread_long( thread, addr + 8192, (long *)limit ) == -1) goto done;
 524         addr = (long *)(unsigned long)thread->process->ldt_copy + 2*8192 + (entry / sizeof(long));
 525         if (read_thread_long( thread, addr, (long *)flags_buf ) == -1) goto done;
 526         *flags = flags_buf[entry % sizeof(long)];
 527     done:
 528         resume_after_ptrace( thread );
 529     }
 530 }
 531
 532
 533 #if defined(linux) && (defined(HAVE_SYS_USER_H) || defined(HAVE_ASM_USER_H)) \
 534     && (defined(__i386__) || defined(__x86_64__))
 535
 536 #ifdef HAVE_SYS_USER_H
 537 #include <sys/user.h>
 538 #elif defined(HAVE_ASM_USER_H)
 539 #include <asm/user.h>
 540 #endif
 541
 542 /* debug register offset in struct user */
 543 #define DR_OFFSET(dr) ((((struct user *)0)->u_debugreg) + (dr))
 544
 545 /* initialize registers in new thread if necessary */
 546 void init_thread_context( struct thread *thread )
 547 {
 548     /* Linux doesn't clear all registers, but hopefully enough to avoid spurious breakpoints */
 549     thread->system_regs = 0;
 550 }
 551
 552 /* retrieve the thread x86 registers */
 553 void get_thread_context( struct thread *thread, context_t *context, unsigned int flags )
 554 {
 555     int i, pid = get_ptrace_tid(thread);
 556     long data[8];
 557
 558     /* all other regs are handled on the client side */
 559     assert( flags == SERVER_CTX_DEBUG_REGISTERS );
 560
 561     if (!suspend_for_ptrace( thread )) return;
 562
 563     if (!(thread->system_regs & SERVER_CTX_DEBUG_REGISTERS))
 564     {
 565         /* caller has initialized everything to 0 already, just return */
 566         context->flags |= SERVER_CTX_DEBUG_REGISTERS;
 567         goto done;
 568     }
 569
 570     for (i = 0; i < 8; i++)
 571     {
 572         if (i == 4 || i == 5) continue;
 573         errno = 0;
 574         data[i] = ptrace( PTRACE_PEEKUSER, pid, DR_OFFSET(i), 0 );
 575         if ((data[i] == -1) && errno)
 576         {
 577             file_set_error();
 578             goto done;
 579         }
 580     }
 581     switch (context->cpu)
 582     {
 583     case CPU_x86:
 584         context->debug.i386_regs.dr0 = data[0];
 585         context->debug.i386_regs.dr1 = data[1];
 586         context->debug.i386_regs.dr2 = data[2];
 587         context->debug.i386_regs.dr3 = data[3];
 588         context->debug.i386_regs.dr6 = data[6];
 589         context->debug.i386_regs.dr7 = data[7];
 590         break;
 591     case CPU_x86_64:
 592         context->debug.x86_64_regs.dr0 = data[0];
 593         context->debug.x86_64_regs.dr1 = data[1];
 594         context->debug.x86_64_regs.dr2 = data[2];
 595         context->debug.x86_64_regs.dr3 = data[3];
 596         context->debug.x86_64_regs.dr6 = data[6];
 597         context->debug.x86_64_regs.dr7 = data[7];
 598         break;
 599     default:
 600         set_error( STATUS_INVALID_PARAMETER );
 601         goto done;
 602     }
 603     context->flags |= SERVER_CTX_DEBUG_REGISTERS;
 604 done:
 605     resume_after_ptrace( thread );
 606 }
 607
 608 /* set the thread x86 registers */
 609 void set_thread_context( struct thread *thread, const context_t *context, unsigned int flags )
 610 {
 611     int pid = get_ptrace_tid( thread );
 612
 613     /* all other regs are handled on the client side */
 614     assert( flags == SERVER_CTX_DEBUG_REGISTERS );
 615
 616     if (!suspend_for_ptrace( thread )) return;
 617
 618     switch (context->cpu)
 619     {
 620     case CPU_x86:
 621         /* Linux 2.6.33+ does DR0-DR3 alignment validation, so it has to know LEN bits first */
 622         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(7), context->debug.i386_regs.dr7 & 0xffff0000 ) == -1) goto error;
 623         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(0), context->debug.i386_regs.dr0 ) == -1) goto error;
 624         if (thread->context) thread->context->debug.i386_regs.dr0 = context->debug.i386_regs.dr0;
 625         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(1), context->debug.i386_regs.dr1 ) == -1) goto error;
 626         if (thread->context) thread->context->debug.i386_regs.dr1 = context->debug.i386_regs.dr1;
 627         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(2), context->debug.i386_regs.dr2 ) == -1) goto error;
 628         if (thread->context) thread->context->debug.i386_regs.dr2 = context->debug.i386_regs.dr2;
 629         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(3), context->debug.i386_regs.dr3 ) == -1) goto error;
 630         if (thread->context) thread->context->debug.i386_regs.dr3 = context->debug.i386_regs.dr3;
 631         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(6), context->debug.i386_regs.dr6 ) == -1) goto error;
 632         if (thread->context) thread->context->debug.i386_regs.dr6 = context->debug.i386_regs.dr6;
 633         /* Linux 2.6.33+ needs enable bits set briefly to update value returned by PEEKUSER later */
 634         ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(7), context->debug.i386_regs.dr7 | 0x55 );
 635         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(7), context->debug.i386_regs.dr7 ) == -1) goto error;
 636         if (thread->context) thread->context->debug.i386_regs.dr7 = context->debug.i386_regs.dr7;
 637         thread->system_regs |= SERVER_CTX_DEBUG_REGISTERS;
 638         break;
 639     case CPU_x86_64:
 640         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(7), context->debug.x86_64_regs.dr7 & 0xffff0000 ) == -1) goto error;
 641         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(0), context->debug.x86_64_regs.dr0 ) == -1) goto error;
 642         if (thread->context) thread->context->debug.x86_64_regs.dr0 = context->debug.x86_64_regs.dr0;
 643         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(1), context->debug.x86_64_regs.dr1 ) == -1) goto error;
 644         if (thread->context) thread->context->debug.x86_64_regs.dr1 = context->debug.x86_64_regs.dr1;
 645         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(2), context->debug.x86_64_regs.dr2 ) == -1) goto error;
 646         if (thread->context) thread->context->debug.x86_64_regs.dr2 = context->debug.x86_64_regs.dr2;
 647         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(3), context->debug.x86_64_regs.dr3 ) == -1) goto error;
 648         if (thread->context) thread->context->debug.x86_64_regs.dr3 = context->debug.x86_64_regs.dr3;
 649         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(6), context->debug.x86_64_regs.dr6 ) == -1) goto error;
 650         if (thread->context) thread->context->debug.x86_64_regs.dr6 = context->debug.x86_64_regs.dr6;
 651         ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(7), context->debug.x86_64_regs.dr7 | 0x55 );
 652         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(7), context->debug.x86_64_regs.dr7 ) == -1) goto error;
 653         if (thread->context) thread->context->debug.x86_64_regs.dr7 = context->debug.x86_64_regs.dr7;
 654         thread->system_regs |= SERVER_CTX_DEBUG_REGISTERS;
 655         break;
 656     default:
 657         set_error( STATUS_INVALID_PARAMETER );
 658     }
 659     resume_after_ptrace( thread );
 660     return;
 661  error:
 662     file_set_error();
 663     resume_after_ptrace( thread );
 664 }
 665
 666 #elif defined(__i386__) && defined(PTRACE_GETDBREGS) && defined(PTRACE_SETDBREGS) && \
 667     (defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined(__OpenBSD__) || defined(__NetBSD__) || defined(__DragonFly__))
 668
 669 #include <machine/reg.h>
 670
 671 /* initialize registers in new thread if necessary */
 672 void init_thread_context( struct thread *thread )
 673 {
 674     if (!(thread->system_regs & SERVER_CTX_DEBUG_REGISTERS)) return;
 675
 676     /* FreeBSD doesn't clear the debug registers in new threads */
 677     if (suspend_for_ptrace( thread ))
 678     {
 679         struct dbreg dbregs;
 680
 681         memset( &dbregs, 0, sizeof(dbregs) );
 682         ptrace( PTRACE_SETDBREGS, get_ptrace_tid( thread ), (caddr_t)&dbregs, 0 );
 683         resume_after_ptrace( thread );
 684     }
 685     thread->system_regs = 0;
 686 }
 687
 688 /* retrieve the thread x86 registers */
 689 void get_thread_context( struct thread *thread, context_t *context, unsigned int flags )
 690 {
 691     int pid = get_ptrace_tid(thread);
 692     struct dbreg dbregs;
 693
 694     /* all other regs are handled on the client side */
 695     assert( flags == SERVER_CTX_DEBUG_REGISTERS );
 696
 697     if (!suspend_for_ptrace( thread )) return;
 698
 699     if (ptrace( PTRACE_GETDBREGS, pid, (caddr_t) &dbregs, 0 ) == -1) file_set_error();
 700     else
 701     {
 702 #ifdef DBREG_DRX
 703         /* needed for FreeBSD, the structure fields have changed under 5.x */
 704         context->debug.i386_regs.dr0 = DBREG_DRX((&dbregs), 0);
 705         context->debug.i386_regs.dr1 = DBREG_DRX((&dbregs), 1);
 706         context->debug.i386_regs.dr2 = DBREG_DRX((&dbregs), 2);
 707         context->debug.i386_regs.dr3 = DBREG_DRX((&dbregs), 3);
 708         context->debug.i386_regs.dr6 = DBREG_DRX((&dbregs), 6);
 709         context->debug.i386_regs.dr7 = DBREG_DRX((&dbregs), 7);
 710 #else
 711         context->debug.i386_regs.dr0 = dbregs.dr0;
 712         context->debug.i386_regs.dr1 = dbregs.dr1;
 713         context->debug.i386_regs.dr2 = dbregs.dr2;
 714         context->debug.i386_regs.dr3 = dbregs.dr3;
 715         context->debug.i386_regs.dr6 = dbregs.dr6;
 716         context->debug.i386_regs.dr7 = dbregs.dr7;
 717 #endif
 718         context->flags |= SERVER_CTX_DEBUG_REGISTERS;
 719     }
 720     resume_after_ptrace( thread );
 721 }
 722
 723 /* set the thread x86 registers */
 724 void set_thread_context( struct thread *thread, const context_t *context, unsigned int flags )
 725 {
 726     int pid = get_ptrace_tid(thread);
 727     struct dbreg dbregs;
 728
 729     /* all other regs are handled on the client side */
 730     assert( flags == SERVER_CTX_DEBUG_REGISTERS );
 731
 732     if (!suspend_for_ptrace( thread )) return;
 733
 734 #ifdef DBREG_DRX
 735     /* needed for FreeBSD, the structure fields have changed under 5.x */
 736     DBREG_DRX((&dbregs), 0) = context->debug.i386_regs.dr0;
 737     DBREG_DRX((&dbregs), 1) = context->debug.i386_regs.dr1;
 738     DBREG_DRX((&dbregs), 2) = context->debug.i386_regs.dr2;
 739     DBREG_DRX((&dbregs), 3) = context->debug.i386_regs.dr3;
 740     DBREG_DRX((&dbregs), 4) = 0;
 741     DBREG_DRX((&dbregs), 5) = 0;
 742     DBREG_DRX((&dbregs), 6) = context->debug.i386_regs.dr6;
 743     DBREG_DRX((&dbregs), 7) = context->debug.i386_regs.dr7;
 744 #else
 745     dbregs.dr0 = context->debug.i386_regs.dr0;
 746     dbregs.dr1 = context->debug.i386_regs.dr1;
 747     dbregs.dr2 = context->debug.i386_regs.dr2;
 748     dbregs.dr3 = context->debug.i386_regs.dr3;
 749     dbregs.dr4 = 0;
 750     dbregs.dr5 = 0;
 751     dbregs.dr6 = context->debug.i386_regs.dr6;
 752     dbregs.dr7 = context->debug.i386_regs.dr7;
 753 #endif
 754     if (ptrace( PTRACE_SETDBREGS, pid, (caddr_t)&dbregs, 0 ) != -1)
 755     {
 756         if (thread->context)
 757             thread->context->debug.i386_regs = context->debug.i386_regs;  /* update the cached values */
 758         thread->system_regs |= SERVER_CTX_DEBUG_REGISTERS;
 759     }
 760     else file_set_error();
 761
 762     resume_after_ptrace( thread );
 763 }
 764
 765 #else  /* linux || __FreeBSD__ */
 766
 767 /* initialize registers in new thread if necessary */
 768 void init_thread_context( struct thread *thread )
 769 {
 770 }
 771
 772 /* retrieve the thread x86 registers */
 773 void get_thread_context( struct thread *thread, context_t *context, unsigned int flags )
 774 {
 775 }
 776
 777 /* set the thread x86 debug registers */
 778 void set_thread_context( struct thread *thread, const context_t *context, unsigned int flags )
 779 {
 780 }
 781
 782 #endif  /* linux || __FreeBSD__ */
 783
 784 #endif  /* USE_PTRACE */