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 #ifndef __WALL
 102 #define __WALL 0
 103 #endif
 104
 105 /* handle a status returned by waitpid */
 106 static int handle_child_status( struct thread *thread, int pid, int status, int want_sig )
 107 {
 108     if (WIFSTOPPED(status))
 109     {
 110         int sig = WSTOPSIG(status);
 111         if (debug_level && thread)
 112             fprintf( stderr, "%04x: *signal* signal=%d\n", thread->id, sig );
 113         if (sig != want_sig)
 114         {
 115             /* ignore other signals for now */
 116             ptrace( PTRACE_CONT, pid, (caddr_t)1, sig );
 117         }
 118         return sig;
 119     }
 120     if (thread && (WIFSIGNALED(status) || WIFEXITED(status)))
 121     {
 122         thread->unix_pid = -1;
 123         thread->unix_tid = -1;
 124         if (debug_level)
 125         {
 126             if (WIFSIGNALED(status))
 127                 fprintf( stderr, "%04x: *exited* signal=%d\n",
 128                          thread->id, WTERMSIG(status) );
 129             else
 130                 fprintf( stderr, "%04x: *exited* status=%d\n",
 131                          thread->id, WEXITSTATUS(status) );
 132         }
 133     }
 134     return 0;
 135 }
 136
 137 /* handle a SIGCHLD signal */
 138 void sigchld_callback(void)
 139 {
 140     int pid, status;
 141
 142     for (;;)
 143     {
 144         if (!(pid = waitpid( -1, &status, WUNTRACED | WNOHANG | __WALL ))) break;
 145         if (pid != -1)
 146         {
 147             struct thread *thread = get_thread_from_tid( pid );
 148             if (!thread) thread = get_thread_from_pid( pid );
 149             handle_child_status( thread, pid, status, -1 );
 150         }
 151         else break;
 152     }
 153 }
 154
 155 /* return the Unix pid to use in ptrace calls for a given process */
 156 static int get_ptrace_pid( struct thread *thread )
 157 {
 158 #ifdef linux  /* linux always uses thread id */
 159     if (thread->unix_tid != -1) return thread->unix_tid;
 160 #endif
 161     return thread->unix_pid;
 162 }
 163
 164 /* return the Unix tid to use in ptrace calls for a given thread */
 165 static int get_ptrace_tid( struct thread *thread )
 166 {
 167     if (thread->unix_tid != -1) return thread->unix_tid;
 168     return thread->unix_pid;
 169 }
 170
 171 /* wait for a ptraced child to get a certain signal */
 172 static int waitpid_thread( struct thread *thread, int signal )
 173 {
 174     int res, status;
 175
 176     start_watchdog();
 177     for (;;)
 178     {
 179         if ((res = waitpid( get_ptrace_pid(thread), &status, WUNTRACED | __WALL )) == -1)
 180         {
 181             if (errno == EINTR)
 182             {
 183                 if (!watchdog_triggered()) continue;
 184                 if (debug_level) fprintf( stderr, "%04x: *watchdog* waitpid aborted\n", thread->id );
 185             }
 186             else if (errno == ECHILD)  /* must have died */
 187             {
 188                 thread->unix_pid = -1;
 189                 thread->unix_tid = -1;
 190             }
 191             else perror( "waitpid" );
 192             stop_watchdog();
 193             return 0;
 194         }
 195         res = handle_child_status( thread, res, status, signal );
 196         if (!res || res == signal) break;
 197     }
 198     stop_watchdog();
 199     return (thread->unix_pid != -1);
 200 }
 201
 202 /* send a signal to a specific thread */
 203 static inline int tkill( int tgid, int pid, int sig )
 204 {
 205 #ifdef __linux__
 206     int ret = syscall( SYS_tgkill, tgid, pid, sig );
 207     if (ret < 0 && errno == ENOSYS) ret = syscall( SYS_tkill, pid, sig );
 208     return ret;
 209 #elif (defined(__FreeBSD__) || defined (__FreeBSD_kernel__)) && defined(HAVE_THR_KILL2)
 210     return thr_kill2( tgid, pid, sig );
 211 #else
 212     errno = ENOSYS;
 213     return -1;
 214 #endif
 215 }
 216
 217 /* initialize the process tracing mechanism */
 218 void init_tracing_mechanism(void)
 219 {
 220     /* no initialization needed for ptrace */
 221 }
 222
 223 /* initialize the per-process tracing mechanism */
 224 void init_process_tracing( struct process *process )
 225 {
 226     /* ptrace setup is done on-demand */
 227 }
 228
 229 /* terminate the per-process tracing mechanism */
 230 void finish_process_tracing( struct process *process )
 231 {
 232 }
 233
 234 /* send a Unix signal to a specific thread */
 235 int send_thread_signal( struct thread *thread, int sig )
 236 {
 237     int ret = -1;
 238
 239     if (thread->unix_pid != -1)
 240     {
 241         if (thread->unix_tid != -1)
 242         {
 243             ret = tkill( thread->unix_pid, thread->unix_tid, sig );
 244             if (ret == -1 && errno == ENOSYS) ret = kill( thread->unix_pid, sig );
 245         }
 246         else ret = kill( thread->unix_pid, sig );
 247
 248         if (ret == -1 && errno == ESRCH) /* thread got killed */
 249         {
 250             thread->unix_pid = -1;
 251             thread->unix_tid = -1;
 252         }
 253     }
 254     if (debug_level && ret != -1)
 255         fprintf( stderr, "%04x: *sent signal* signal=%d\n", thread->id, sig );
 256     return (ret != -1);
 257 }
 258
 259 /* resume a thread after we have used ptrace on it */
 260 static void resume_after_ptrace( struct thread *thread )
 261 {
 262     if (thread->unix_pid == -1) return;
 263     if (ptrace( PTRACE_DETACH, get_ptrace_pid(thread), (caddr_t)1, 0 ) == -1)
 264     {
 265         if (errno == ESRCH) thread->unix_pid = thread->unix_tid = -1;  /* thread got killed */
 266     }
 267 }
 268
 269 /* suspend a thread to allow using ptrace on it */
 270 /* you must do a resume_after_ptrace when finished with the thread */
 271 static int suspend_for_ptrace( struct thread *thread )
 272 {
 273     /* can't stop a thread while initialisation is in progress */
 274     if (thread->unix_pid == -1 || !is_process_init_done(thread->process)) goto error;
 275
 276     /* this may fail if the client is already being debugged */
 277     if (ptrace( PTRACE_ATTACH, get_ptrace_pid(thread), 0, 0 ) == -1)
 278     {
 279         if (errno == ESRCH) thread->unix_pid = thread->unix_tid = -1;  /* thread got killed */
 280         goto error;
 281     }
 282     if (waitpid_thread( thread, SIGSTOP )) return 1;
 283     resume_after_ptrace( thread );
 284  error:
 285     set_error( STATUS_ACCESS_DENIED );
 286     return 0;
 287 }
 288
 289 /* read a long from a thread address space */
 290 static long read_thread_long( struct thread *thread, long *addr, long *data )
 291 {
 292     errno = 0;
 293     *data = ptrace( PTRACE_PEEKDATA, get_ptrace_pid(thread), (caddr_t)addr, 0 );
 294     if ( *data == -1 && errno)
 295     {
 296         file_set_error();
 297         return -1;
 298     }
 299     return 0;
 300 }
 301
 302 /* write a long to a thread address space */
 303 static long write_thread_long( struct thread *thread, long *addr, long data, unsigned long mask )
 304 {
 305     long res;
 306     if (mask != ~0ul)
 307     {
 308         if (read_thread_long( thread, addr, &res ) == -1) return -1;
 309         data = (data & mask) | (res & ~mask);
 310     }
 311     if ((res = ptrace( PTRACE_POKEDATA, get_ptrace_pid(thread), (caddr_t)addr, data )) == -1)
 312         file_set_error();
 313     return res;
 314 }
 315
 316 /* return a thread of the process suitable for ptracing */
 317 static struct thread *get_ptrace_thread( struct process *process )
 318 {
 319     struct thread *thread;
 320
 321     LIST_FOR_EACH_ENTRY( thread, &process->thread_list, struct thread, proc_entry )
 322     {
 323         if (thread->unix_pid != -1) return thread;
 324     }
 325     set_error( STATUS_ACCESS_DENIED );  /* process is dead */
 326     return NULL;
 327 }
 328
 329 /* read data from a process memory space */
 330 int read_process_memory( struct process *process, client_ptr_t ptr, data_size_t size, char *dest )
 331 {
 332     struct thread *thread = get_ptrace_thread( process );
 333     unsigned int first_offset, last_offset, len;
 334     long data, *addr;
 335
 336     if (!thread) return 0;
 337
 338     if ((unsigned long)ptr != ptr)
 339     {
 340         set_error( STATUS_ACCESS_DENIED );
 341         return 0;
 342     }
 343
 344     first_offset = ptr % sizeof(long);
 345     last_offset = (size + first_offset) % sizeof(long);
 346     if (!last_offset) last_offset = sizeof(long);
 347
 348     addr = (long *)(unsigned long)(ptr - first_offset);
 349     len = (size + first_offset + sizeof(long) - 1) / sizeof(long);
 350
 351     if (suspend_for_ptrace( thread ))
 352     {
 353         if (len > 3)  /* /proc/pid/mem should be faster for large sizes */
 354         {
 355             char procmem[24];
 356             int fd;
 357
 358             sprintf( procmem, "/proc/%u/mem", process->unix_pid );
 359             if ((fd = open( procmem, O_RDONLY )) != -1)
 360             {
 361                 ssize_t ret = pread( fd, dest, size, ptr );
 362                 close( fd );
 363                 if (ret == size)
 364                 {
 365                     len = 0;
 366                     goto done;
 367                 }
 368             }
 369         }
 370
 371         if (len > 1)
 372         {
 373             if (read_thread_long( thread, addr++, &data ) == -1) goto done;
 374             memcpy( dest, (char *)&data + first_offset, sizeof(long) - first_offset );
 375             dest += sizeof(long) - first_offset;
 376             first_offset = 0;
 377             len--;
 378         }
 379
 380         while (len > 1)
 381         {
 382             if (read_thread_long( thread, addr++, &data ) == -1) goto done;
 383             memcpy( dest, &data, sizeof(long) );
 384             dest += sizeof(long);
 385             len--;
 386         }
 387
 388         if (read_thread_long( thread, addr++, &data ) == -1) goto done;
 389         memcpy( dest, (char *)&data + first_offset, last_offset - first_offset );
 390         len--;
 391
 392     done:
 393         resume_after_ptrace( thread );
 394     }
 395     return !len;
 396 }
 397
 398 /* make sure we can write to the whole address range */
 399 /* len is the total size (in ints) */
 400 static int check_process_write_access( struct thread *thread, long *addr, data_size_t len )
 401 {
 402     int page = get_page_size() / sizeof(int);
 403
 404     for (;;)
 405     {
 406         if (write_thread_long( thread, addr, 0, 0 ) == -1) return 0;
 407         if (len <= page) break;
 408         addr += page;
 409         len -= page;
 410     }
 411     return (write_thread_long( thread, addr + len - 1, 0, 0 ) != -1);
 412 }
 413
 414 /* write data to a process memory space */
 415 int write_process_memory( struct process *process, client_ptr_t ptr, data_size_t size, const char *src )
 416 {
 417     struct thread *thread = get_ptrace_thread( process );
 418     int ret = 0;
 419     long data = 0;
 420     data_size_t len;
 421     long *addr;
 422     unsigned long first_mask, first_offset, last_mask, last_offset;
 423
 424     if (!thread) return 0;
 425
 426     if ((unsigned long)ptr != ptr)
 427     {
 428         set_error( STATUS_ACCESS_DENIED );
 429         return 0;
 430     }
 431
 432     /* compute the mask for the first long */
 433     first_mask = ~0;
 434     first_offset = ptr % sizeof(long);
 435     memset( &first_mask, 0, first_offset );
 436
 437     /* compute the mask for the last long */
 438     last_offset = (size + first_offset) % sizeof(long);
 439     if (!last_offset) last_offset = sizeof(long);
 440     last_mask = 0;
 441     memset( &last_mask, 0xff, last_offset );
 442
 443     addr = (long *)(unsigned long)(ptr - first_offset);
 444     len = (size + first_offset + sizeof(long) - 1) / sizeof(long);
 445
 446     if (suspend_for_ptrace( thread ))
 447     {
 448         if (!check_process_write_access( thread, addr, len ))
 449         {
 450             set_error( STATUS_ACCESS_DENIED );
 451             goto done;
 452         }
 453
 454         if (len > 3)
 455         {
 456             char procmem[24];
 457             int fd;
 458
 459             sprintf( procmem, "/proc/%u/mem", process->unix_pid );
 460             if ((fd = open( procmem, O_WRONLY )) != -1)
 461             {
 462                 ssize_t r = pwrite( fd, src, size, ptr );
 463                 close( fd );
 464                 if (r == size)
 465                 {
 466                     ret = 1;
 467                     goto done;
 468                 }
 469             }
 470         }
 471
 472         /* first word is special */
 473         if (len > 1)
 474         {
 475             memcpy( (char *)&data + first_offset, src, sizeof(long) - first_offset );
 476             src += sizeof(long) - first_offset;
 477             if (write_thread_long( thread, addr++, data, first_mask ) == -1) goto done;
 478             first_offset = 0;
 479             len--;
 480         }
 481         else last_mask &= first_mask;
 482
 483         while (len > 1)
 484         {
 485             memcpy( &data, src, sizeof(long) );
 486             src += sizeof(long);
 487             if (write_thread_long( thread, addr++, data, ~0ul ) == -1) goto done;
 488             len--;
 489         }
 490
 491         /* last word is special too */
 492         memcpy( (char *)&data + first_offset, src, last_offset - first_offset );
 493         if (write_thread_long( thread, addr, data, last_mask ) == -1) goto done;
 494         ret = 1;
 495
 496     done:
 497         resume_after_ptrace( thread );
 498     }
 499     return ret;
 500 }
 501
 502 /* retrieve an LDT selector entry */
 503 void get_selector_entry( struct thread *thread, int entry, unsigned int *base,
 504                          unsigned int *limit, unsigned char *flags )
 505 {
 506     if (!thread->process->ldt_copy)
 507     {
 508         set_error( STATUS_ACCESS_DENIED );
 509         return;
 510     }
 511     if (entry >= 8192)
 512     {
 513         set_error( STATUS_ACCESS_VIOLATION );
 514         return;
 515     }
 516     if (suspend_for_ptrace( thread ))
 517     {
 518         unsigned char flags_buf[sizeof(long)];
 519         long *addr = (long *)(unsigned long)thread->process->ldt_copy + entry;
 520         if (read_thread_long( thread, addr, (long *)base ) == -1) goto done;
 521         if (read_thread_long( thread, addr + 8192, (long *)limit ) == -1) goto done;
 522         addr = (long *)(unsigned long)thread->process->ldt_copy + 2*8192 + (entry / sizeof(long));
 523         if (read_thread_long( thread, addr, (long *)flags_buf ) == -1) goto done;
 524         *flags = flags_buf[entry % sizeof(long)];
 525     done:
 526         resume_after_ptrace( thread );
 527     }
 528 }
 529
 530
 531 #if defined(linux) && (defined(__i386__) || defined(__x86_64__))
 532
 533 #ifdef HAVE_SYS_USER_H
 534 # include <sys/user.h>
 535 #endif
 536
 537 /* debug register offset in struct user */
 538 #define DR_OFFSET(dr) ((((struct user *)0)->u_debugreg) + (dr))
 539
 540 /* retrieve the thread x86 registers */
 541 void get_thread_context( struct thread *thread, context_t *context, unsigned int flags )
 542 {
 543     int i, pid = get_ptrace_tid(thread);
 544     long data[8];
 545
 546     /* all other regs are handled on the client side */
 547     assert( flags == SERVER_CTX_DEBUG_REGISTERS );
 548
 549     if (!suspend_for_ptrace( thread )) return;
 550
 551     for (i = 0; i < 8; i++)
 552     {
 553         if (i == 4 || i == 5) continue;
 554         errno = 0;
 555         data[i] = ptrace( PTRACE_PEEKUSER, pid, DR_OFFSET(i), 0 );
 556         if ((data[i] == -1) && errno)
 557         {
 558             file_set_error();
 559             goto done;
 560         }
 561     }
 562     switch (context->cpu)
 563     {
 564     case CPU_x86:
 565         context->debug.i386_regs.dr0 = data[0];
 566         context->debug.i386_regs.dr1 = data[1];
 567         context->debug.i386_regs.dr2 = data[2];
 568         context->debug.i386_regs.dr3 = data[3];
 569         context->debug.i386_regs.dr6 = data[6];
 570         context->debug.i386_regs.dr7 = data[7];
 571         break;
 572     case CPU_x86_64:
 573         context->debug.x86_64_regs.dr0 = data[0];
 574         context->debug.x86_64_regs.dr1 = data[1];
 575         context->debug.x86_64_regs.dr2 = data[2];
 576         context->debug.x86_64_regs.dr3 = data[3];
 577         context->debug.x86_64_regs.dr6 = data[6];
 578         context->debug.x86_64_regs.dr7 = data[7];
 579         break;
 580     default:
 581         set_error( STATUS_INVALID_PARAMETER );
 582         goto done;
 583     }
 584     context->flags |= SERVER_CTX_DEBUG_REGISTERS;
 585 done:
 586     resume_after_ptrace( thread );
 587 }
 588
 589 /* set the thread x86 registers */
 590 void set_thread_context( struct thread *thread, const context_t *context, unsigned int flags )
 591 {
 592     int pid = get_ptrace_tid( thread );
 593
 594     /* all other regs are handled on the client side */
 595     assert( flags == SERVER_CTX_DEBUG_REGISTERS );
 596
 597     if (!suspend_for_ptrace( thread )) return;
 598
 599     switch (context->cpu)
 600     {
 601     case CPU_x86:
 602         /* Linux 2.6.33+ does DR0-DR3 alignment validation, so it has to know LEN bits first */
 603         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(7), context->debug.i386_regs.dr7 & 0xffff0000 ) == -1) goto error;
 604         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(0), context->debug.i386_regs.dr0 ) == -1) goto error;
 605         if (thread->context) thread->context->debug.i386_regs.dr0 = context->debug.i386_regs.dr0;
 606         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(1), context->debug.i386_regs.dr1 ) == -1) goto error;
 607         if (thread->context) thread->context->debug.i386_regs.dr1 = context->debug.i386_regs.dr1;
 608         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(2), context->debug.i386_regs.dr2 ) == -1) goto error;
 609         if (thread->context) thread->context->debug.i386_regs.dr2 = context->debug.i386_regs.dr2;
 610         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(3), context->debug.i386_regs.dr3 ) == -1) goto error;
 611         if (thread->context) thread->context->debug.i386_regs.dr3 = context->debug.i386_regs.dr3;
 612         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(6), context->debug.i386_regs.dr6 ) == -1) goto error;
 613         if (thread->context) thread->context->debug.i386_regs.dr6 = context->debug.i386_regs.dr6;
 614         /* Linux 2.6.33+ needs enable bits set briefly to update value returned by PEEKUSER later */
 615         ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(7), context->debug.i386_regs.dr7 | 0x55 );
 616         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(7), context->debug.i386_regs.dr7 ) == -1) goto error;
 617         if (thread->context) thread->context->debug.i386_regs.dr7 = context->debug.i386_regs.dr7;
 618         break;
 619     case CPU_x86_64:
 620         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(7), context->debug.x86_64_regs.dr7 & 0xffff0000 ) == -1) goto error;
 621         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(0), context->debug.x86_64_regs.dr0 ) == -1) goto error;
 622         if (thread->context) thread->context->debug.x86_64_regs.dr0 = context->debug.x86_64_regs.dr0;
 623         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(1), context->debug.x86_64_regs.dr1 ) == -1) goto error;
 624         if (thread->context) thread->context->debug.x86_64_regs.dr1 = context->debug.x86_64_regs.dr1;
 625         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(2), context->debug.x86_64_regs.dr2 ) == -1) goto error;
 626         if (thread->context) thread->context->debug.x86_64_regs.dr2 = context->debug.x86_64_regs.dr2;
 627         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(3), context->debug.x86_64_regs.dr3 ) == -1) goto error;
 628         if (thread->context) thread->context->debug.x86_64_regs.dr3 = context->debug.x86_64_regs.dr3;
 629         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(6), context->debug.x86_64_regs.dr6 ) == -1) goto error;
 630         if (thread->context) thread->context->debug.x86_64_regs.dr6 = context->debug.x86_64_regs.dr6;
 631         ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(7), context->debug.x86_64_regs.dr7 | 0x55 );
 632         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(7), context->debug.x86_64_regs.dr7 ) == -1) goto error;
 633         if (thread->context) thread->context->debug.x86_64_regs.dr7 = context->debug.x86_64_regs.dr7;
 634         break;
 635     default:
 636         set_error( STATUS_INVALID_PARAMETER );
 637     }
 638     resume_after_ptrace( thread );
 639     return;
 640  error:
 641     file_set_error();
 642     resume_after_ptrace( thread );
 643 }
 644
 645 #elif defined(__i386__) && defined(PTRACE_GETDBREGS) && defined(PTRACE_SETDBREGS) && \
 646     (defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined(__OpenBSD__) || defined(__NetBSD__) || defined(__DragonFly__))
 647
 648 #include <machine/reg.h>
 649
 650 /* retrieve the thread x86 registers */
 651 void get_thread_context( struct thread *thread, context_t *context, unsigned int flags )
 652 {
 653     int pid = get_ptrace_tid(thread);
 654     struct dbreg dbregs;
 655
 656     /* all other regs are handled on the client side */
 657     assert( flags == SERVER_CTX_DEBUG_REGISTERS );
 658
 659     if (!suspend_for_ptrace( thread )) return;
 660
 661     if (ptrace( PTRACE_GETDBREGS, pid, (caddr_t) &dbregs, 0 ) == -1) file_set_error();
 662     else
 663     {
 664 #ifdef DBREG_DRX
 665         /* needed for FreeBSD, the structure fields have changed under 5.x */
 666         context->debug.i386_regs.dr0 = DBREG_DRX((&dbregs), 0);
 667         context->debug.i386_regs.dr1 = DBREG_DRX((&dbregs), 1);
 668         context->debug.i386_regs.dr2 = DBREG_DRX((&dbregs), 2);
 669         context->debug.i386_regs.dr3 = DBREG_DRX((&dbregs), 3);
 670         context->debug.i386_regs.dr6 = DBREG_DRX((&dbregs), 6);
 671         context->debug.i386_regs.dr7 = DBREG_DRX((&dbregs), 7);
 672 #else
 673         context->debug.i386_regs.dr0 = dbregs.dr0;
 674         context->debug.i386_regs.dr1 = dbregs.dr1;
 675         context->debug.i386_regs.dr2 = dbregs.dr2;
 676         context->debug.i386_regs.dr3 = dbregs.dr3;
 677         context->debug.i386_regs.dr6 = dbregs.dr6;
 678         context->debug.i386_regs.dr7 = dbregs.dr7;
 679 #endif
 680         context->flags |= SERVER_CTX_DEBUG_REGISTERS;
 681     }
 682     resume_after_ptrace( thread );
 683 }
 684
 685 /* set the thread x86 registers */
 686 void set_thread_context( struct thread *thread, const context_t *context, unsigned int flags )
 687 {
 688     int pid = get_ptrace_tid(thread);
 689     struct dbreg dbregs;
 690
 691     /* all other regs are handled on the client side */
 692     assert( flags == SERVER_CTX_DEBUG_REGISTERS );
 693
 694     if (!suspend_for_ptrace( thread )) return;
 695
 696 #ifdef DBREG_DRX
 697     /* needed for FreeBSD, the structure fields have changed under 5.x */
 698     DBREG_DRX((&dbregs), 0) = context->debug.i386_regs.dr0;
 699     DBREG_DRX((&dbregs), 1) = context->debug.i386_regs.dr1;
 700     DBREG_DRX((&dbregs), 2) = context->debug.i386_regs.dr2;
 701     DBREG_DRX((&dbregs), 3) = context->debug.i386_regs.dr3;
 702     DBREG_DRX((&dbregs), 4) = 0;
 703     DBREG_DRX((&dbregs), 5) = 0;
 704     DBREG_DRX((&dbregs), 6) = context->debug.i386_regs.dr6;
 705     DBREG_DRX((&dbregs), 7) = context->debug.i386_regs.dr7;
 706 #else
 707     dbregs.dr0 = context->debug.i386_regs.dr0;
 708     dbregs.dr1 = context->debug.i386_regs.dr1;
 709     dbregs.dr2 = context->debug.i386_regs.dr2;
 710     dbregs.dr3 = context->debug.i386_regs.dr3;
 711     dbregs.dr4 = 0;
 712     dbregs.dr5 = 0;
 713     dbregs.dr6 = context->debug.i386_regs.dr6;
 714     dbregs.dr7 = context->debug.i386_regs.dr7;
 715 #endif
 716     if (ptrace( PTRACE_SETDBREGS, pid, (caddr_t) &dbregs, 0 ) == -1) file_set_error();
 717     else if (thread->context)
 718         thread->context->debug.i386_regs = context->debug.i386_regs;  /* update the cached values */
 719     resume_after_ptrace( thread );
 720 }
 721
 722 #else  /* linux || __FreeBSD__ */
 723
 724 /* retrieve the thread x86 registers */
 725 void get_thread_context( struct thread *thread, context_t *context, unsigned int flags )
 726 {
 727 }
 728
 729 /* set the thread x86 debug registers */
 730 void set_thread_context( struct thread *thread, const context_t *context, unsigned int flags )
 731 {
 732 }
 733
 734 #endif  /* linux || __FreeBSD__ */
 735
 736 #endif  /* USE_PTRACE */