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