2 * Server-side ptrace support
4 * Copyright (C) 1999 Alexandre Julliard
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.
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.
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
28 #include <sys/types.h>
29 #ifdef HAVE_SYS_PTRACE_H
30 # include <sys/ptrace.h>
32 #ifdef HAVE_SYS_PARAM_H
33 # include <sys/param.h>
35 #ifdef HAVE_SYS_WAIT_H
36 # include <sys/wait.h>
41 #define WIN32_NO_STATUS
49 #define PTRACE_CONT PT_CONTINUE
51 #ifndef PTRACE_SINGLESTEP
52 #define PTRACE_SINGLESTEP PT_STEP
55 #define PTRACE_ATTACH PT_ATTACH
58 #define PTRACE_DETACH PT_DETACH
60 #ifndef PTRACE_PEEKDATA
61 #define PTRACE_PEEKDATA PT_READ_D
63 #ifndef PTRACE_POKEDATA
64 #define PTRACE_POKEDATA PT_WRITE_D
66 #ifndef PTRACE_PEEKUSER
67 #define PTRACE_PEEKUSER PT_READ_U
69 #ifndef PTRACE_POKEUSER
70 #define PTRACE_POKEUSER PT_WRITE_U
74 #define PTRACE_GETDBREGS PT_GETDBREGS
77 #define PTRACE_SETDBREGS PT_SETDBREGS
80 #ifndef HAVE_SYS_PTRACE_H
87 inline static int ptrace(int req, ...) { errno = EPERM; return -1; /*FAIL*/ }
88 #endif /* HAVE_SYS_PTRACE_H */
90 /* handle a status returned by wait4 */
91 static int handle_child_status( struct thread *thread, int pid, int status, int want_sig )
93 if (WIFSTOPPED(status))
95 int sig = WSTOPSIG(status);
96 if (debug_level && thread)
97 fprintf( stderr, "%04x: *signal* signal=%d\n", thread->id, sig );
100 /* ignore other signals for now */
101 ptrace( PTRACE_CONT, pid, (caddr_t)1, sig );
105 if (thread && (WIFSIGNALED(status) || WIFEXITED(status)))
107 thread->unix_pid = -1;
108 thread->unix_tid = -1;
111 if (WIFSIGNALED(status))
112 fprintf( stderr, "%04x: *exited* signal=%d\n",
113 thread->id, WTERMSIG(status) );
115 fprintf( stderr, "%04x: *exited* status=%d\n",
116 thread->id, WEXITSTATUS(status) );
122 /* wait4 wrapper to handle missing __WALL flag in older kernels */
123 static inline pid_t wait4_wrapper( pid_t pid, int *status, int options, struct rusage *usage )
126 static int wall_flag = __WALL;
130 pid_t ret = wait4( pid, status, options | wall_flag, usage );
131 if (ret != -1 || !wall_flag || errno != EINVAL) return ret;
135 return wait4( pid, status, options, usage );
139 /* handle a SIGCHLD signal */
140 void sigchld_callback(void)
146 if (!(pid = wait4_wrapper( -1, &status, WUNTRACED | WNOHANG, NULL ))) break;
147 if (pid != -1) handle_child_status( get_thread_from_pid(pid), pid, status, -1 );
152 /* return the Unix pid to use in ptrace calls for a given thread */
153 static int get_ptrace_pid( struct thread *thread )
155 if (thread->unix_tid != -1) return thread->unix_tid;
156 return thread->unix_pid;
159 /* wait for a ptraced child to get a certain signal */
160 static int wait4_thread( struct thread *thread, int signal )
167 if ((res = wait4_wrapper( get_ptrace_pid(thread), &status, WUNTRACED, NULL )) == -1)
171 if (!watchdog_triggered()) continue;
172 if (debug_level) fprintf( stderr, "%04x: *watchdog* wait4 aborted\n", thread->id );
174 else if (errno == ECHILD) /* must have died */
176 thread->unix_pid = -1;
177 thread->unix_tid = -1;
179 else perror( "wait4" );
183 res = handle_child_status( thread, res, status, signal );
184 if (!res || res == signal) break;
187 return (thread->unix_pid != -1);
190 /* send a signal to a specific thread */
191 static inline int tkill( int tgid, int pid, int sig )
197 __asm__( "pushl %%ebx\n\t"
202 : "0" (270) /*SYS_tgkill*/, "r" (tgid), "c" (pid), "d" (sig) );
204 __asm__( "pushl %%ebx\n\t"
209 : "0" (238) /*SYS_tkill*/, "r" (pid), "c" (sig) );
210 # elif defined(__x86_64__)
211 __asm__( "syscall" : "=a" (ret)
212 : "0" (200) /*SYS_tkill*/, "D" (pid), "S" (sig) );
214 #endif /* __linux__ */
216 if (ret >= 0) return ret;
221 /* send a Unix signal to a specific thread */
222 int send_thread_signal( struct thread *thread, int sig )
226 if (thread->unix_pid != -1)
228 if (thread->unix_tid != -1)
230 ret = tkill( thread->unix_pid, thread->unix_tid, sig );
231 if (ret == -1 && errno == ENOSYS) ret = kill( thread->unix_pid, sig );
233 else ret = kill( thread->unix_pid, sig );
235 if (ret == -1 && errno == ESRCH) /* thread got killed */
237 thread->unix_pid = -1;
238 thread->unix_tid = -1;
244 /* resume a thread after we have used ptrace on it */
245 static void resume_after_ptrace( struct thread *thread )
247 if (thread->unix_pid == -1) return;
248 if (ptrace( PTRACE_DETACH, get_ptrace_pid(thread), (caddr_t)1, 0 ) == -1)
250 if (errno == ESRCH) thread->unix_pid = thread->unix_tid = -1; /* thread got killed */
254 /* suspend a thread to allow using ptrace on it */
255 /* you must do a resume_after_ptrace when finished with the thread */
256 static int suspend_for_ptrace( struct thread *thread )
258 /* can't stop a thread while initialisation is in progress */
259 if (thread->unix_pid == -1 || !is_process_init_done(thread->process)) goto error;
261 /* this may fail if the client is already being debugged */
262 if (ptrace( PTRACE_ATTACH, get_ptrace_pid(thread), 0, 0 ) == -1)
264 if (errno == ESRCH) thread->unix_pid = thread->unix_tid = -1; /* thread got killed */
267 if (wait4_thread( thread, SIGSTOP )) return 1;
268 resume_after_ptrace( thread );
270 set_error( STATUS_ACCESS_DENIED );
274 /* read an int from a thread address space */
275 static int read_thread_int( struct thread *thread, const int *addr, int *data )
278 *data = ptrace( PTRACE_PEEKDATA, get_ptrace_pid(thread), (caddr_t)addr, 0 );
279 if ( *data == -1 && errno)
287 /* write an int to a thread address space */
288 static int write_thread_int( struct thread *thread, int *addr, int data, unsigned int mask )
293 if (read_thread_int( thread, addr, &res ) == -1) return -1;
294 data = (data & mask) | (res & ~mask);
296 if ((res = ptrace( PTRACE_POKEDATA, get_ptrace_pid(thread), (caddr_t)addr, data )) == -1)
301 /* read data from a process memory space */
302 int read_process_memory( struct process *process, const void *ptr, size_t size, char *dest )
304 struct thread *thread = get_process_first_thread( process );
305 unsigned int first_offset, last_offset, len;
308 if (!thread) /* process is dead */
310 set_error( STATUS_ACCESS_DENIED );
314 first_offset = (unsigned long)ptr % sizeof(int);
315 last_offset = (size + first_offset) % sizeof(int);
316 if (!last_offset) last_offset = sizeof(int);
318 addr = (int *)((char *)ptr - first_offset);
319 len = (size + first_offset + sizeof(int) - 1) / sizeof(int);
321 if (suspend_for_ptrace( thread ))
325 if (read_thread_int( thread, addr++, &data ) == -1) goto done;
326 memcpy( dest, (char *)&data + first_offset, sizeof(int) - first_offset );
327 dest += sizeof(int) - first_offset;
334 if (read_thread_int( thread, addr++, &data ) == -1) goto done;
335 memcpy( dest, &data, sizeof(int) );
340 if (read_thread_int( thread, addr++, &data ) == -1) goto done;
341 memcpy( dest, (char *)&data + first_offset, last_offset - first_offset );
345 resume_after_ptrace( thread );
350 /* make sure we can write to the whole address range */
351 /* len is the total size (in ints) */
352 static int check_process_write_access( struct thread *thread, int *addr, size_t len )
354 int page = get_page_size() / sizeof(int);
358 if (write_thread_int( thread, addr, 0, 0 ) == -1) return 0;
359 if (len <= page) break;
363 return (write_thread_int( thread, addr + len - 1, 0, 0 ) != -1);
366 /* write data to a process memory space */
367 int write_process_memory( struct process *process, void *ptr, size_t size, const char *src )
369 struct thread *thread = get_process_first_thread( process );
370 int ret = 0, data = 0;
373 unsigned int first_mask, first_offset, last_mask, last_offset;
375 if (!thread) /* process is dead */
377 set_error( STATUS_ACCESS_DENIED );
381 /* compute the mask for the first int */
383 first_offset = (unsigned long)ptr % sizeof(int);
384 memset( &first_mask, 0, first_offset );
386 /* compute the mask for the last int */
387 last_offset = (size + first_offset) % sizeof(int);
388 if (!last_offset) last_offset = sizeof(int);
390 memset( &last_mask, 0xff, last_offset );
392 addr = (int *)((char *)ptr - first_offset);
393 len = (size + first_offset + sizeof(int) - 1) / sizeof(int);
395 if (suspend_for_ptrace( thread ))
397 if (!check_process_write_access( thread, addr, len ))
399 set_error( STATUS_ACCESS_DENIED );
402 /* first word is special */
405 memcpy( (char *)&data + first_offset, src, sizeof(int) - first_offset );
406 src += sizeof(int) - first_offset;
407 if (write_thread_int( thread, addr++, data, first_mask ) == -1) goto done;
411 else last_mask &= first_mask;
415 memcpy( &data, src, sizeof(int) );
417 if (write_thread_int( thread, addr++, data, ~0 ) == -1) goto done;
421 /* last word is special too */
422 memcpy( (char *)&data + first_offset, src, last_offset - first_offset );
423 if (write_thread_int( thread, addr, data, last_mask ) == -1) goto done;
427 resume_after_ptrace( thread );
432 /* retrieve an LDT selector entry */
433 void get_selector_entry( struct thread *thread, int entry, unsigned int *base,
434 unsigned int *limit, unsigned char *flags )
436 if (!thread->process->ldt_copy)
438 set_error( STATUS_ACCESS_DENIED );
443 set_error( STATUS_INVALID_PARAMETER ); /* FIXME */
446 if (suspend_for_ptrace( thread ))
448 unsigned char flags_buf[4];
449 int *addr = (int *)thread->process->ldt_copy + entry;
450 if (read_thread_int( thread, addr, (int *)base ) == -1) goto done;
451 if (read_thread_int( thread, addr + 8192, (int *)limit ) == -1) goto done;
452 addr = (int *)thread->process->ldt_copy + 2*8192 + (entry >> 2);
453 if (read_thread_int( thread, addr, (int *)flags_buf ) == -1) goto done;
454 *flags = flags_buf[entry & 3];
456 resume_after_ptrace( thread );
461 #if defined(linux) && (defined(__i386__) || defined(__x86_64__))
463 #ifdef HAVE_SYS_USER_H
464 # include <sys/user.h>
467 /* debug register offset in struct user */
468 #define DR_OFFSET(dr) ((((struct user *)0)->u_debugreg) + (dr))
470 /* retrieve the thread x86 registers */
471 void get_thread_context( struct thread *thread, CONTEXT *context, unsigned int flags )
473 int i, pid = get_ptrace_pid(thread);
476 /* all other regs are handled on the client side */
477 assert( (flags | CONTEXT_i386) == CONTEXT_DEBUG_REGISTERS );
479 if (!suspend_for_ptrace( thread )) return;
481 for (i = 0; i < 8; i++)
483 if (i == 4 || i == 5) continue;
485 data[i] = ptrace( PTRACE_PEEKUSER, pid, DR_OFFSET(i), 0 );
486 if ((data[i] == -1) && errno)
492 context->Dr0 = data[0];
493 context->Dr1 = data[1];
494 context->Dr2 = data[2];
495 context->Dr3 = data[3];
496 context->Dr6 = data[6];
497 context->Dr7 = data[7];
498 context->ContextFlags |= CONTEXT_DEBUG_REGISTERS;
500 resume_after_ptrace( thread );
503 /* set the thread x86 registers */
504 void set_thread_context( struct thread *thread, const CONTEXT *context, unsigned int flags )
506 int pid = get_ptrace_pid( thread );
508 /* all other regs are handled on the client side */
509 assert( (flags | CONTEXT_i386) == CONTEXT_DEBUG_REGISTERS );
511 if (!suspend_for_ptrace( thread )) return;
513 if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(0), context->Dr0 ) == -1) goto error;
514 if (thread->context) thread->context->Dr0 = context->Dr0;
515 if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(1), context->Dr1 ) == -1) goto error;
516 if (thread->context) thread->context->Dr1 = context->Dr1;
517 if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(2), context->Dr2 ) == -1) goto error;
518 if (thread->context) thread->context->Dr2 = context->Dr2;
519 if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(3), context->Dr3 ) == -1) goto error;
520 if (thread->context) thread->context->Dr3 = context->Dr3;
521 if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(6), context->Dr6 ) == -1) goto error;
522 if (thread->context) thread->context->Dr6 = context->Dr6;
523 if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(7), context->Dr7 ) == -1) goto error;
524 if (thread->context) thread->context->Dr7 = context->Dr7;
525 resume_after_ptrace( thread );
529 resume_after_ptrace( thread );
532 #elif defined(__i386__) && defined(PTRACE_GETDBREGS) && defined(PTRACE_SETDBREGS) && \
533 (defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined(__OpenBSD__) || defined(__NetBSD__))
535 #include <machine/reg.h>
537 /* retrieve the thread x86 registers */
538 void get_thread_context( struct thread *thread, CONTEXT *context, unsigned int flags )
540 int pid = get_ptrace_pid(thread);
543 /* all other regs are handled on the client side */
544 assert( (flags | CONTEXT_i386) == CONTEXT_DEBUG_REGISTERS );
546 if (!suspend_for_ptrace( thread )) return;
548 if (ptrace( PTRACE_GETDBREGS, pid, (caddr_t) &dbregs, 0 ) == -1) file_set_error();
552 /* needed for FreeBSD, the structure fields have changed under 5.x */
553 context->Dr0 = DBREG_DRX((&dbregs), 0);
554 context->Dr1 = DBREG_DRX((&dbregs), 1);
555 context->Dr2 = DBREG_DRX((&dbregs), 2);
556 context->Dr3 = DBREG_DRX((&dbregs), 3);
557 context->Dr6 = DBREG_DRX((&dbregs), 6);
558 context->Dr7 = DBREG_DRX((&dbregs), 7);
560 context->Dr0 = dbregs.dr0;
561 context->Dr1 = dbregs.dr1;
562 context->Dr2 = dbregs.dr2;
563 context->Dr3 = dbregs.dr3;
564 context->Dr6 = dbregs.dr6;
565 context->Dr7 = dbregs.dr7;
567 context->ContextFlags |= CONTEXT_DEBUG_REGISTERS;
569 resume_after_ptrace( thread );
572 /* set the thread x86 registers */
573 void set_thread_context( struct thread *thread, const CONTEXT *context, unsigned int flags )
575 int pid = get_ptrace_pid(thread);
578 /* all other regs are handled on the client side */
579 assert( (flags | CONTEXT_i386) == CONTEXT_DEBUG_REGISTERS );
581 if (!suspend_for_ptrace( thread )) return;
584 /* needed for FreeBSD, the structure fields have changed under 5.x */
585 DBREG_DRX((&dbregs), 0) = context->Dr0;
586 DBREG_DRX((&dbregs), 1) = context->Dr1;
587 DBREG_DRX((&dbregs), 2) = context->Dr2;
588 DBREG_DRX((&dbregs), 3) = context->Dr3;
589 DBREG_DRX((&dbregs), 4) = 0;
590 DBREG_DRX((&dbregs), 5) = 0;
591 DBREG_DRX((&dbregs), 6) = context->Dr6;
592 DBREG_DRX((&dbregs), 7) = context->Dr7;
594 dbregs.dr0 = context->Dr0;
595 dbregs.dr1 = context->Dr1;
596 dbregs.dr2 = context->Dr2;
597 dbregs.dr3 = context->Dr3;
600 dbregs.dr6 = context->Dr6;
601 dbregs.dr7 = context->Dr7;
603 if (ptrace( PTRACE_SETDBREGS, pid, (caddr_t) &dbregs, 0 ) == -1) file_set_error();
604 else if (thread->context) /* update the cached values */
606 thread->context->Dr0 = context->Dr0;
607 thread->context->Dr1 = context->Dr1;
608 thread->context->Dr2 = context->Dr2;
609 thread->context->Dr3 = context->Dr3;
610 thread->context->Dr6 = context->Dr6;
611 thread->context->Dr7 = context->Dr7;
613 resume_after_ptrace( thread );
616 #else /* linux || __FreeBSD__ */
618 /* retrieve the thread x86 registers */
619 void get_thread_context( struct thread *thread, CONTEXT *context, unsigned int flags )
623 /* set the thread x86 debug registers */
624 void set_thread_context( struct thread *thread, const CONTEXT *context, unsigned int flags )
628 #endif /* linux || __FreeBSD__ */