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_THR_H
  44 # include <sys/ucontext.h>
  45 # include <sys/thr.h>
  46 #endif
  47 #include <unistd.h>
  48
  49 #include "ntstatus.h"
  50 #define WIN32_NO_STATUS
  51 #include "winternl.h"
  52
  53 #include "file.h"
  54 #include "process.h"
  55 #include "thread.h"
  56
  57 #ifdef USE_PTRACE
  58
  59 #ifndef PTRACE_CONT
  60 #define PTRACE_CONT PT_CONTINUE
  61 #endif
  62 #ifndef PTRACE_SINGLESTEP
  63 #define PTRACE_SINGLESTEP PT_STEP
  64 #endif
  65 #ifndef PTRACE_ATTACH
  66 #define PTRACE_ATTACH PT_ATTACH
  67 #endif
  68 #ifndef PTRACE_DETACH
  69 #define PTRACE_DETACH PT_DETACH
  70 #endif
  71 #ifndef PTRACE_PEEKDATA
  72 #define PTRACE_PEEKDATA PT_READ_D
  73 #endif
  74 #ifndef PTRACE_POKEDATA
  75 #define PTRACE_POKEDATA PT_WRITE_D
  76 #endif
  77 #ifndef PTRACE_PEEKUSER
  78 #define PTRACE_PEEKUSER PT_READ_U
  79 #endif
  80 #ifndef PTRACE_POKEUSER
  81 #define PTRACE_POKEUSER PT_WRITE_U
  82 #endif
  83
  84 #ifdef PT_GETDBREGS
  85 #define PTRACE_GETDBREGS PT_GETDBREGS
  86 #endif
  87 #ifdef PT_SETDBREGS
  88 #define PTRACE_SETDBREGS PT_SETDBREGS
  89 #endif
  90
  91 #ifndef HAVE_SYS_PTRACE_H
  92 #define PT_CONTINUE 0
  93 #define PT_ATTACH   1
  94 #define PT_DETACH   2
  95 #define PT_READ_D   3
  96 #define PT_WRITE_D  4
  97 #define PT_STEP     5
  98 static inline int ptrace(int req, ...) { errno = EPERM; return -1; /*FAIL*/ }
  99 #endif  /* HAVE_SYS_PTRACE_H */
 100
 101 /* handle a status returned by wait4 */
 102 static int handle_child_status( struct thread *thread, int pid, int status, int want_sig )
 103 {
 104     if (WIFSTOPPED(status))
 105     {
 106         int sig = WSTOPSIG(status);
 107         if (debug_level && thread)
 108             fprintf( stderr, "%04x: *signal* signal=%d\n", thread->id, sig );
 109         if (sig != want_sig)
 110         {
 111             /* ignore other signals for now */
 112             ptrace( PTRACE_CONT, pid, (caddr_t)1, sig );
 113         }
 114         return sig;
 115     }
 116     if (thread && (WIFSIGNALED(status) || WIFEXITED(status)))
 117     {
 118         thread->unix_pid = -1;
 119         thread->unix_tid = -1;
 120         if (debug_level)
 121         {
 122             if (WIFSIGNALED(status))
 123                 fprintf( stderr, "%04x: *exited* signal=%d\n",
 124                          thread->id, WTERMSIG(status) );
 125             else
 126                 fprintf( stderr, "%04x: *exited* status=%d\n",
 127                          thread->id, WEXITSTATUS(status) );
 128         }
 129     }
 130     return 0;
 131 }
 132
 133 /* wait4 wrapper to handle missing __WALL flag in older kernels */
 134 static inline pid_t wait4_wrapper( pid_t pid, int *status, int options, struct rusage *usage )
 135 {
 136 #ifdef __WALL
 137     static int wall_flag = __WALL;
 138
 139     for (;;)
 140     {
 141         pid_t ret = wait4( pid, status, options | wall_flag, usage );
 142         if (ret != -1 || !wall_flag || errno != EINVAL) return ret;
 143         wall_flag = 0;
 144     }
 145 #else
 146     return wait4( pid, status, options, usage );
 147 #endif
 148 }
 149
 150 /* handle a SIGCHLD signal */
 151 void sigchld_callback(void)
 152 {
 153     int pid, status;
 154
 155     for (;;)
 156     {
 157         if (!(pid = wait4_wrapper( -1, &status, WUNTRACED | WNOHANG, NULL ))) break;
 158         if (pid != -1)
 159         {
 160             struct thread *thread = get_thread_from_tid( pid );
 161             if (!thread) thread = get_thread_from_pid( pid );
 162             handle_child_status( thread, pid, status, -1 );
 163         }
 164         else break;
 165     }
 166 }
 167
 168 /* return the Unix pid to use in ptrace calls for a given process */
 169 static int get_ptrace_pid( struct thread *thread )
 170 {
 171 #ifdef linux  /* linux always uses thread id */
 172     if (thread->unix_tid != -1) return thread->unix_tid;
 173 #endif
 174     return thread->unix_pid;
 175 }
 176
 177 /* return the Unix tid to use in ptrace calls for a given thread */
 178 static int get_ptrace_tid( struct thread *thread )
 179 {
 180     if (thread->unix_tid != -1) return thread->unix_tid;
 181     return thread->unix_pid;
 182 }
 183
 184 /* wait for a ptraced child to get a certain signal */
 185 static int wait4_thread( struct thread *thread, int signal )
 186 {
 187     int res, status;
 188
 189     start_watchdog();
 190     for (;;)
 191     {
 192         if ((res = wait4_wrapper( get_ptrace_pid(thread), &status, WUNTRACED, NULL )) == -1)
 193         {
 194             if (errno == EINTR)
 195             {
 196                 if (!watchdog_triggered()) continue;
 197                 if (debug_level) fprintf( stderr, "%04x: *watchdog* wait4 aborted\n", thread->id );
 198             }
 199             else if (errno == ECHILD)  /* must have died */
 200             {
 201                 thread->unix_pid = -1;
 202                 thread->unix_tid = -1;
 203             }
 204             else perror( "wait4" );
 205             stop_watchdog();
 206             return 0;
 207         }
 208         res = handle_child_status( thread, res, status, signal );
 209         if (!res || res == signal) break;
 210     }
 211     stop_watchdog();
 212     return (thread->unix_pid != -1);
 213 }
 214
 215 /* send a signal to a specific thread */
 216 static inline int tkill( int tgid, int pid, int sig )
 217 {
 218 #ifdef __linux__
 219     int ret = syscall( SYS_tgkill, tgid, pid, sig );
 220     if (ret < 0 && errno == ENOSYS) ret = syscall( SYS_tkill, pid, sig );
 221     return ret;
 222 #elif (defined(__FreeBSD__) || defined (__FreeBSD_kernel__)) && defined(HAVE_THR_KILL2)
 223     return thr_kill2( tgid, pid, sig );
 224 #else
 225     errno = ENOSYS;
 226     return -1;
 227 #endif
 228 }
 229
 230 /* initialize the process tracing mechanism */
 231 void init_tracing_mechanism(void)
 232 {
 233     /* no initialization needed for ptrace */
 234 }
 235
 236 /* initialize the per-process tracing mechanism */
 237 void init_process_tracing( struct process *process )
 238 {
 239     /* ptrace setup is done on-demand */
 240 }
 241
 242 /* terminate the per-process tracing mechanism */
 243 void finish_process_tracing( struct process *process )
 244 {
 245 }
 246
 247 /* send a Unix signal to a specific thread */
 248 int send_thread_signal( struct thread *thread, int sig )
 249 {
 250     int ret = -1;
 251
 252     if (thread->unix_pid != -1)
 253     {
 254         if (thread->unix_tid != -1)
 255         {
 256             ret = tkill( thread->unix_pid, thread->unix_tid, sig );
 257             if (ret == -1 && errno == ENOSYS) ret = kill( thread->unix_pid, sig );
 258         }
 259         else ret = kill( thread->unix_pid, sig );
 260
 261         if (ret == -1 && errno == ESRCH) /* thread got killed */
 262         {
 263             thread->unix_pid = -1;
 264             thread->unix_tid = -1;
 265         }
 266     }
 267     if (debug_level && ret != -1)
 268         fprintf( stderr, "%04x: *sent signal* signal=%d\n", thread->id, sig );
 269     return (ret != -1);
 270 }
 271
 272 /* resume a thread after we have used ptrace on it */
 273 static void resume_after_ptrace( struct thread *thread )
 274 {
 275     if (thread->unix_pid == -1) return;
 276     if (ptrace( PTRACE_DETACH, get_ptrace_pid(thread), (caddr_t)1, 0 ) == -1)
 277     {
 278         if (errno == ESRCH) thread->unix_pid = thread->unix_tid = -1;  /* thread got killed */
 279     }
 280 }
 281
 282 /* suspend a thread to allow using ptrace on it */
 283 /* you must do a resume_after_ptrace when finished with the thread */
 284 static int suspend_for_ptrace( struct thread *thread )
 285 {
 286     /* can't stop a thread while initialisation is in progress */
 287     if (thread->unix_pid == -1 || !is_process_init_done(thread->process)) goto error;
 288
 289     /* this may fail if the client is already being debugged */
 290     if (ptrace( PTRACE_ATTACH, get_ptrace_pid(thread), 0, 0 ) == -1)
 291     {
 292         if (errno == ESRCH) thread->unix_pid = thread->unix_tid = -1;  /* thread got killed */
 293         goto error;
 294     }
 295     if (wait4_thread( thread, SIGSTOP )) return 1;
 296     resume_after_ptrace( thread );
 297  error:
 298     set_error( STATUS_ACCESS_DENIED );
 299     return 0;
 300 }
 301
 302 /* read a long from a thread address space */
 303 static long read_thread_long( struct thread *thread, long *addr, long *data )
 304 {
 305     errno = 0;
 306     *data = ptrace( PTRACE_PEEKDATA, get_ptrace_pid(thread), (caddr_t)addr, 0 );
 307     if ( *data == -1 && errno)
 308     {
 309         file_set_error();
 310         return -1;
 311     }
 312     return 0;
 313 }
 314
 315 /* write a long to a thread address space */
 316 static long write_thread_long( struct thread *thread, long *addr, long data, unsigned long mask )
 317 {
 318     long res;
 319     if (mask != ~0ul)
 320     {
 321         if (read_thread_long( thread, addr, &res ) == -1) return -1;
 322         data = (data & mask) | (res & ~mask);
 323     }
 324     if ((res = ptrace( PTRACE_POKEDATA, get_ptrace_pid(thread), (caddr_t)addr, data )) == -1)
 325         file_set_error();
 326     return res;
 327 }
 328
 329 /* return a thread of the process suitable for ptracing */
 330 static struct thread *get_ptrace_thread( struct process *process )
 331 {
 332     struct thread *thread;
 333
 334     LIST_FOR_EACH_ENTRY( thread, &process->thread_list, struct thread, proc_entry )
 335     {
 336         if (thread->unix_pid != -1) return thread;
 337     }
 338     set_error( STATUS_ACCESS_DENIED );  /* process is dead */
 339     return NULL;
 340 }
 341
 342 /* read data from a process memory space */
 343 int read_process_memory( struct process *process, client_ptr_t ptr, data_size_t size, char *dest )
 344 {
 345     struct thread *thread = get_ptrace_thread( process );
 346     unsigned int first_offset, last_offset, len;
 347     long data, *addr;
 348
 349     if (!thread) return 0;
 350
 351     if ((unsigned long)ptr != ptr)
 352     {
 353         set_error( STATUS_ACCESS_DENIED );
 354         return 0;
 355     }
 356
 357     first_offset = ptr % sizeof(long);
 358     last_offset = (size + first_offset) % sizeof(long);
 359     if (!last_offset) last_offset = sizeof(long);
 360
 361     addr = (long *)(unsigned long)(ptr - first_offset);
 362     len = (size + first_offset + sizeof(long) - 1) / sizeof(long);
 363
 364     if (suspend_for_ptrace( thread ))
 365     {
 366         if (len > 3)  /* /proc/pid/mem should be faster for large sizes */
 367         {
 368             char procmem[24];
 369             int fd;
 370
 371             sprintf( procmem, "/proc/%u/mem", process->unix_pid );
 372             if ((fd = open( procmem, O_RDONLY )) != -1)
 373             {
 374                 ssize_t ret = pread( fd, dest, size, ptr );
 375                 close( fd );
 376                 if (ret == size)
 377                 {
 378                     len = 0;
 379                     goto done;
 380                 }
 381             }
 382         }
 383
 384         if (len > 1)
 385         {
 386             if (read_thread_long( thread, addr++, &data ) == -1) goto done;
 387             memcpy( dest, (char *)&data + first_offset, sizeof(long) - first_offset );
 388             dest += sizeof(long) - first_offset;
 389             first_offset = 0;
 390             len--;
 391         }
 392
 393         while (len > 1)
 394         {
 395             if (read_thread_long( thread, addr++, &data ) == -1) goto done;
 396             memcpy( dest, &data, sizeof(long) );
 397             dest += sizeof(long);
 398             len--;
 399         }
 400
 401         if (read_thread_long( thread, addr++, &data ) == -1) goto done;
 402         memcpy( dest, (char *)&data + first_offset, last_offset - first_offset );
 403         len--;
 404
 405     done:
 406         resume_after_ptrace( thread );
 407     }
 408     return !len;
 409 }
 410
 411 /* make sure we can write to the whole address range */
 412 /* len is the total size (in ints) */
 413 static int check_process_write_access( struct thread *thread, long *addr, data_size_t len )
 414 {
 415     int page = get_page_size() / sizeof(int);
 416
 417     for (;;)
 418     {
 419         if (write_thread_long( thread, addr, 0, 0 ) == -1) return 0;
 420         if (len <= page) break;
 421         addr += page;
 422         len -= page;
 423     }
 424     return (write_thread_long( thread, addr + len - 1, 0, 0 ) != -1);
 425 }
 426
 427 /* write data to a process memory space */
 428 int write_process_memory( struct process *process, client_ptr_t ptr, data_size_t size, const char *src )
 429 {
 430     struct thread *thread = get_ptrace_thread( process );
 431     int ret = 0;
 432     long data = 0;
 433     data_size_t len;
 434     long *addr;
 435     unsigned long first_mask, first_offset, last_mask, last_offset;
 436
 437     if (!thread) return 0;
 438
 439     if ((unsigned long)ptr != ptr)
 440     {
 441         set_error( STATUS_ACCESS_DENIED );
 442         return 0;
 443     }
 444
 445     /* compute the mask for the first long */
 446     first_mask = ~0;
 447     first_offset = ptr % sizeof(long);
 448     memset( &first_mask, 0, first_offset );
 449
 450     /* compute the mask for the last long */
 451     last_offset = (size + first_offset) % sizeof(long);
 452     if (!last_offset) last_offset = sizeof(long);
 453     last_mask = 0;
 454     memset( &last_mask, 0xff, last_offset );
 455
 456     addr = (long *)(unsigned long)(ptr - first_offset);
 457     len = (size + first_offset + sizeof(long) - 1) / sizeof(long);
 458
 459     if (suspend_for_ptrace( thread ))
 460     {
 461         if (!check_process_write_access( thread, addr, len ))
 462         {
 463             set_error( STATUS_ACCESS_DENIED );
 464             goto done;
 465         }
 466         /* first word is special */
 467         if (len > 1)
 468         {
 469             memcpy( (char *)&data + first_offset, src, sizeof(long) - first_offset );
 470             src += sizeof(long) - first_offset;
 471             if (write_thread_long( thread, addr++, data, first_mask ) == -1) goto done;
 472             first_offset = 0;
 473             len--;
 474         }
 475         else last_mask &= first_mask;
 476
 477         while (len > 1)
 478         {
 479             memcpy( &data, src, sizeof(long) );
 480             src += sizeof(long);
 481             if (write_thread_long( thread, addr++, data, ~0ul ) == -1) goto done;
 482             len--;
 483         }
 484
 485         /* last word is special too */
 486         memcpy( (char *)&data + first_offset, src, last_offset - first_offset );
 487         if (write_thread_long( thread, addr, data, last_mask ) == -1) goto done;
 488         ret = 1;
 489
 490     done:
 491         resume_after_ptrace( thread );
 492     }
 493     return ret;
 494 }
 495
 496 /* retrieve an LDT selector entry */
 497 void get_selector_entry( struct thread *thread, int entry, unsigned int *base,
 498                          unsigned int *limit, unsigned char *flags )
 499 {
 500     if (!thread->process->ldt_copy)
 501     {
 502         set_error( STATUS_ACCESS_DENIED );
 503         return;
 504     }
 505     if (entry >= 8192)
 506     {
 507         set_error( STATUS_ACCESS_VIOLATION );
 508         return;
 509     }
 510     if (suspend_for_ptrace( thread ))
 511     {
 512         unsigned char flags_buf[sizeof(long)];
 513         long *addr = (long *)(unsigned long)thread->process->ldt_copy + entry;
 514         if (read_thread_long( thread, addr, (long *)base ) == -1) goto done;
 515         if (read_thread_long( thread, addr + 8192, (long *)limit ) == -1) goto done;
 516         addr = (long *)(unsigned long)thread->process->ldt_copy + 2*8192 + (entry / sizeof(long));
 517         if (read_thread_long( thread, addr, (long *)flags_buf ) == -1) goto done;
 518         *flags = flags_buf[entry % sizeof(long)];
 519     done:
 520         resume_after_ptrace( thread );
 521     }
 522 }
 523
 524
 525 #if defined(linux) && (defined(__i386__) || defined(__x86_64__))
 526
 527 #ifdef HAVE_SYS_USER_H
 528 # include <sys/user.h>
 529 #endif
 530
 531 /* debug register offset in struct user */
 532 #define DR_OFFSET(dr) ((((struct user *)0)->u_debugreg) + (dr))
 533
 534 /* retrieve the thread x86 registers */
 535 void get_thread_context( struct thread *thread, context_t *context, unsigned int flags )
 536 {
 537     int i, pid = get_ptrace_tid(thread);
 538     long data[8];
 539
 540     /* all other regs are handled on the client side */
 541     assert( flags == SERVER_CTX_DEBUG_REGISTERS );
 542
 543     if (!suspend_for_ptrace( thread )) return;
 544
 545     for (i = 0; i < 8; i++)
 546     {
 547         if (i == 4 || i == 5) continue;
 548         errno = 0;
 549         data[i] = ptrace( PTRACE_PEEKUSER, pid, DR_OFFSET(i), 0 );
 550         if ((data[i] == -1) && errno)
 551         {
 552             file_set_error();
 553             goto done;
 554         }
 555     }
 556     switch (context->cpu)
 557     {
 558     case CPU_x86:
 559         context->debug.i386_regs.dr0 = data[0];
 560         context->debug.i386_regs.dr1 = data[1];
 561         context->debug.i386_regs.dr2 = data[2];
 562         context->debug.i386_regs.dr3 = data[3];
 563         context->debug.i386_regs.dr6 = data[6];
 564         context->debug.i386_regs.dr7 = data[7];
 565         break;
 566     case CPU_x86_64:
 567         context->debug.x86_64_regs.dr0 = data[0];
 568         context->debug.x86_64_regs.dr1 = data[1];
 569         context->debug.x86_64_regs.dr2 = data[2];
 570         context->debug.x86_64_regs.dr3 = data[3];
 571         context->debug.x86_64_regs.dr6 = data[6];
 572         context->debug.x86_64_regs.dr7 = data[7];
 573         break;
 574     default:
 575         set_error( STATUS_INVALID_PARAMETER );
 576         goto done;
 577     }
 578     context->flags |= SERVER_CTX_DEBUG_REGISTERS;
 579 done:
 580     resume_after_ptrace( thread );
 581 }
 582
 583 /* set the thread x86 registers */
 584 void set_thread_context( struct thread *thread, const context_t *context, unsigned int flags )
 585 {
 586     int pid = get_ptrace_tid( thread );
 587
 588     /* all other regs are handled on the client side */
 589     assert( flags == SERVER_CTX_DEBUG_REGISTERS );
 590
 591     if (!suspend_for_ptrace( thread )) return;
 592
 593     switch (context->cpu)
 594     {
 595     case CPU_x86:
 596         /* Linux 2.6.33+ does DR0-DR3 alignment validation, so it has to know LEN bits first */
 597         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(7), context->debug.i386_regs.dr7 & 0xffff0000 ) == -1) goto error;
 598         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(0), context->debug.i386_regs.dr0 ) == -1) goto error;
 599         if (thread->context) thread->context->debug.i386_regs.dr0 = context->debug.i386_regs.dr0;
 600         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(1), context->debug.i386_regs.dr1 ) == -1) goto error;
 601         if (thread->context) thread->context->debug.i386_regs.dr1 = context->debug.i386_regs.dr1;
 602         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(2), context->debug.i386_regs.dr2 ) == -1) goto error;
 603         if (thread->context) thread->context->debug.i386_regs.dr2 = context->debug.i386_regs.dr2;
 604         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(3), context->debug.i386_regs.dr3 ) == -1) goto error;
 605         if (thread->context) thread->context->debug.i386_regs.dr3 = context->debug.i386_regs.dr3;
 606         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(6), context->debug.i386_regs.dr6 ) == -1) goto error;
 607         if (thread->context) thread->context->debug.i386_regs.dr6 = context->debug.i386_regs.dr6;
 608         /* Linux 2.6.33+ needs enable bits set briefly to update value returned by PEEKUSER later */
 609         ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(7), context->debug.i386_regs.dr7 | 0x55 );
 610         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(7), context->debug.i386_regs.dr7 ) == -1) goto error;
 611         if (thread->context) thread->context->debug.i386_regs.dr7 = context->debug.i386_regs.dr7;
 612         break;
 613     case CPU_x86_64:
 614         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(7), context->debug.x86_64_regs.dr7 & 0xffff0000 ) == -1) goto error;
 615         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(0), context->debug.x86_64_regs.dr0 ) == -1) goto error;
 616         if (thread->context) thread->context->debug.x86_64_regs.dr0 = context->debug.x86_64_regs.dr0;
 617         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(1), context->debug.x86_64_regs.dr1 ) == -1) goto error;
 618         if (thread->context) thread->context->debug.x86_64_regs.dr1 = context->debug.x86_64_regs.dr1;
 619         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(2), context->debug.x86_64_regs.dr2 ) == -1) goto error;
 620         if (thread->context) thread->context->debug.x86_64_regs.dr2 = context->debug.x86_64_regs.dr2;
 621         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(3), context->debug.x86_64_regs.dr3 ) == -1) goto error;
 622         if (thread->context) thread->context->debug.x86_64_regs.dr3 = context->debug.x86_64_regs.dr3;
 623         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(6), context->debug.x86_64_regs.dr6 ) == -1) goto error;
 624         if (thread->context) thread->context->debug.x86_64_regs.dr6 = context->debug.x86_64_regs.dr6;
 625         ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(7), context->debug.x86_64_regs.dr7 | 0x55 );
 626         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(7), context->debug.x86_64_regs.dr7 ) == -1) goto error;
 627         if (thread->context) thread->context->debug.x86_64_regs.dr7 = context->debug.x86_64_regs.dr7;
 628         break;
 629     default:
 630         set_error( STATUS_INVALID_PARAMETER );
 631     }
 632     resume_after_ptrace( thread );
 633     return;
 634  error:
 635     file_set_error();
 636     resume_after_ptrace( thread );
 637 }
 638
 639 #elif defined(__i386__) && defined(PTRACE_GETDBREGS) && defined(PTRACE_SETDBREGS) && \
 640     (defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined(__OpenBSD__) || defined(__NetBSD__))
 641
 642 #include <machine/reg.h>
 643
 644 /* retrieve the thread x86 registers */
 645 void get_thread_context( struct thread *thread, context_t *context, unsigned int flags )
 646 {
 647     int pid = get_ptrace_tid(thread);
 648     struct dbreg dbregs;
 649
 650     /* all other regs are handled on the client side */
 651     assert( flags == SERVER_CTX_DEBUG_REGISTERS );
 652
 653     if (!suspend_for_ptrace( thread )) return;
 654
 655     if (ptrace( PTRACE_GETDBREGS, pid, (caddr_t) &dbregs, 0 ) == -1) file_set_error();
 656     else
 657     {
 658 #ifdef DBREG_DRX
 659         /* needed for FreeBSD, the structure fields have changed under 5.x */
 660         context->debug.i386_regs.dr0 = DBREG_DRX((&dbregs), 0);
 661         context->debug.i386_regs.dr1 = DBREG_DRX((&dbregs), 1);
 662         context->debug.i386_regs.dr2 = DBREG_DRX((&dbregs), 2);
 663         context->debug.i386_regs.dr3 = DBREG_DRX((&dbregs), 3);
 664         context->debug.i386_regs.dr6 = DBREG_DRX((&dbregs), 6);
 665         context->debug.i386_regs.dr7 = DBREG_DRX((&dbregs), 7);
 666 #else
 667         context->debug.i386_regs.dr0 = dbregs.dr0;
 668         context->debug.i386_regs.dr1 = dbregs.dr1;
 669         context->debug.i386_regs.dr2 = dbregs.dr2;
 670         context->debug.i386_regs.dr3 = dbregs.dr3;
 671         context->debug.i386_regs.dr6 = dbregs.dr6;
 672         context->debug.i386_regs.dr7 = dbregs.dr7;
 673 #endif
 674         context->flags |= SERVER_CTX_DEBUG_REGISTERS;
 675     }
 676     resume_after_ptrace( thread );
 677 }
 678
 679 /* set the thread x86 registers */
 680 void set_thread_context( struct thread *thread, const context_t *context, unsigned int flags )
 681 {
 682     int pid = get_ptrace_tid(thread);
 683     struct dbreg dbregs;
 684
 685     /* all other regs are handled on the client side */
 686     assert( flags == SERVER_CTX_DEBUG_REGISTERS );
 687
 688     if (!suspend_for_ptrace( thread )) return;
 689
 690 #ifdef DBREG_DRX
 691     /* needed for FreeBSD, the structure fields have changed under 5.x */
 692     DBREG_DRX((&dbregs), 0) = context->debug.i386_regs.dr0;
 693     DBREG_DRX((&dbregs), 1) = context->debug.i386_regs.dr1;
 694     DBREG_DRX((&dbregs), 2) = context->debug.i386_regs.dr2;
 695     DBREG_DRX((&dbregs), 3) = context->debug.i386_regs.dr3;
 696     DBREG_DRX((&dbregs), 4) = 0;
 697     DBREG_DRX((&dbregs), 5) = 0;
 698     DBREG_DRX((&dbregs), 6) = context->debug.i386_regs.dr6;
 699     DBREG_DRX((&dbregs), 7) = context->debug.i386_regs.dr7;
 700 #else
 701     dbregs.dr0 = context->debug.i386_regs.dr0;
 702     dbregs.dr1 = context->debug.i386_regs.dr1;
 703     dbregs.dr2 = context->debug.i386_regs.dr2;
 704     dbregs.dr3 = context->debug.i386_regs.dr3;
 705     dbregs.dr4 = 0;
 706     dbregs.dr5 = 0;
 707     dbregs.dr6 = context->debug.i386_regs.dr6;
 708     dbregs.dr7 = context->debug.i386_regs.dr7;
 709 #endif
 710     if (ptrace( PTRACE_SETDBREGS, pid, (caddr_t) &dbregs, 0 ) == -1) file_set_error();
 711     else if (thread->context)
 712         thread->context->debug.i386_regs = context->debug.i386_regs;  /* update the cached values */
 713     resume_after_ptrace( thread );
 714 }
 715
 716 #else  /* linux || __FreeBSD__ */
 717
 718 /* retrieve the thread x86 registers */
 719 void get_thread_context( struct thread *thread, context_t *context, unsigned int flags )
 720 {
 721 }
 722
 723 /* set the thread x86 debug registers */
 724 void set_thread_context( struct thread *thread, const context_t *context, unsigned int flags )
 725 {
 726 }
 727
 728 #endif  /* linux || __FreeBSD__ */
 729
 730 #endif  /* USE_PTRACE */