pipe: fix pipe buffer resizing
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / kernel / ptrace.c
blob74a3d693c196810f9eed784a2825ea50a7f9db83
1 /*
2 * linux/kernel/ptrace.c
4 * (C) Copyright 1999 Linus Torvalds
6 * Common interfaces for "ptrace()" which we do not want
7 * to continually duplicate across every architecture.
8 */
10 #include <linux/capability.h>
11 #include <linux/module.h>
12 #include <linux/sched.h>
13 #include <linux/errno.h>
14 #include <linux/mm.h>
15 #include <linux/highmem.h>
16 #include <linux/pagemap.h>
17 #include <linux/ptrace.h>
18 #include <linux/security.h>
19 #include <linux/signal.h>
20 #include <linux/audit.h>
21 #include <linux/pid_namespace.h>
22 #include <linux/syscalls.h>
23 #include <linux/uaccess.h>
24 #include <linux/regset.h>
28 * ptrace a task: make the debugger its new parent and
29 * move it to the ptrace list.
31 * Must be called with the tasklist lock write-held.
33 void __ptrace_link(struct task_struct *child, struct task_struct *new_parent)
35 BUG_ON(!list_empty(&child->ptrace_entry));
36 list_add(&child->ptrace_entry, &new_parent->ptraced);
37 child->parent = new_parent;
41 * Turn a tracing stop into a normal stop now, since with no tracer there
42 * would be no way to wake it up with SIGCONT or SIGKILL. If there was a
43 * signal sent that would resume the child, but didn't because it was in
44 * TASK_TRACED, resume it now.
45 * Requires that irqs be disabled.
47 static void ptrace_untrace(struct task_struct *child)
49 spin_lock(&child->sighand->siglock);
50 if (task_is_traced(child)) {
52 * If the group stop is completed or in progress,
53 * this thread was already counted as stopped.
55 if (child->signal->flags & SIGNAL_STOP_STOPPED ||
56 child->signal->group_stop_count)
57 __set_task_state(child, TASK_STOPPED);
58 else
59 signal_wake_up(child, 1);
61 spin_unlock(&child->sighand->siglock);
65 * unptrace a task: move it back to its original parent and
66 * remove it from the ptrace list.
68 * Must be called with the tasklist lock write-held.
70 void __ptrace_unlink(struct task_struct *child)
72 BUG_ON(!child->ptrace);
74 child->ptrace = 0;
75 child->parent = child->real_parent;
76 list_del_init(&child->ptrace_entry);
78 if (task_is_traced(child))
79 ptrace_untrace(child);
83 * Check that we have indeed attached to the thing..
85 int ptrace_check_attach(struct task_struct *child, int kill)
87 int ret = -ESRCH;
90 * We take the read lock around doing both checks to close a
91 * possible race where someone else was tracing our child and
92 * detached between these two checks. After this locked check,
93 * we are sure that this is our traced child and that can only
94 * be changed by us so it's not changing right after this.
96 read_lock(&tasklist_lock);
97 if ((child->ptrace & PT_PTRACED) && child->parent == current) {
98 ret = 0;
100 * child->sighand can't be NULL, release_task()
101 * does ptrace_unlink() before __exit_signal().
103 spin_lock_irq(&child->sighand->siglock);
104 if (task_is_stopped(child))
105 child->state = TASK_TRACED;
106 else if (!task_is_traced(child) && !kill)
107 ret = -ESRCH;
108 spin_unlock_irq(&child->sighand->siglock);
110 read_unlock(&tasklist_lock);
112 if (!ret && !kill)
113 ret = wait_task_inactive(child, TASK_TRACED) ? 0 : -ESRCH;
115 /* All systems go.. */
116 return ret;
119 int __ptrace_may_access(struct task_struct *task, unsigned int mode)
121 const struct cred *cred = current_cred(), *tcred;
123 /* May we inspect the given task?
124 * This check is used both for attaching with ptrace
125 * and for allowing access to sensitive information in /proc.
127 * ptrace_attach denies several cases that /proc allows
128 * because setting up the necessary parent/child relationship
129 * or halting the specified task is impossible.
131 int dumpable = 0;
132 /* Don't let security modules deny introspection */
133 if (task == current)
134 return 0;
135 rcu_read_lock();
136 tcred = __task_cred(task);
137 if ((cred->uid != tcred->euid ||
138 cred->uid != tcred->suid ||
139 cred->uid != tcred->uid ||
140 cred->gid != tcred->egid ||
141 cred->gid != tcred->sgid ||
142 cred->gid != tcred->gid) &&
143 !capable(CAP_SYS_PTRACE)) {
144 rcu_read_unlock();
145 return -EPERM;
147 rcu_read_unlock();
148 smp_rmb();
149 if (task->mm)
150 dumpable = get_dumpable(task->mm);
151 if (!dumpable && !capable(CAP_SYS_PTRACE))
152 return -EPERM;
154 return security_ptrace_access_check(task, mode);
157 bool ptrace_may_access(struct task_struct *task, unsigned int mode)
159 int err;
160 task_lock(task);
161 err = __ptrace_may_access(task, mode);
162 task_unlock(task);
163 return !err;
166 int ptrace_attach(struct task_struct *task)
168 int retval;
170 audit_ptrace(task);
172 retval = -EPERM;
173 if (unlikely(task->flags & PF_KTHREAD))
174 goto out;
175 if (same_thread_group(task, current))
176 goto out;
179 * Protect exec's credential calculations against our interference;
180 * interference; SUID, SGID and LSM creds get determined differently
181 * under ptrace.
183 retval = -ERESTARTNOINTR;
184 if (mutex_lock_interruptible(&task->cred_guard_mutex))
185 goto out;
187 task_lock(task);
188 retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH);
189 task_unlock(task);
190 if (retval)
191 goto unlock_creds;
193 write_lock_irq(&tasklist_lock);
194 retval = -EPERM;
195 if (unlikely(task->exit_state))
196 goto unlock_tasklist;
197 if (task->ptrace)
198 goto unlock_tasklist;
200 task->ptrace = PT_PTRACED;
201 if (capable(CAP_SYS_PTRACE))
202 task->ptrace |= PT_PTRACE_CAP;
204 __ptrace_link(task, current);
205 send_sig_info(SIGSTOP, SEND_SIG_FORCED, task);
207 retval = 0;
208 unlock_tasklist:
209 write_unlock_irq(&tasklist_lock);
210 unlock_creds:
211 mutex_unlock(&task->cred_guard_mutex);
212 out:
213 return retval;
217 * ptrace_traceme -- helper for PTRACE_TRACEME
219 * Performs checks and sets PT_PTRACED.
220 * Should be used by all ptrace implementations for PTRACE_TRACEME.
222 int ptrace_traceme(void)
224 int ret = -EPERM;
226 write_lock_irq(&tasklist_lock);
227 /* Are we already being traced? */
228 if (!current->ptrace) {
229 ret = security_ptrace_traceme(current->parent);
231 * Check PF_EXITING to ensure ->real_parent has not passed
232 * exit_ptrace(). Otherwise we don't report the error but
233 * pretend ->real_parent untraces us right after return.
235 if (!ret && !(current->real_parent->flags & PF_EXITING)) {
236 current->ptrace = PT_PTRACED;
237 __ptrace_link(current, current->real_parent);
240 write_unlock_irq(&tasklist_lock);
242 return ret;
246 * Called with irqs disabled, returns true if childs should reap themselves.
248 static int ignoring_children(struct sighand_struct *sigh)
250 int ret;
251 spin_lock(&sigh->siglock);
252 ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) ||
253 (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT);
254 spin_unlock(&sigh->siglock);
255 return ret;
259 * Called with tasklist_lock held for writing.
260 * Unlink a traced task, and clean it up if it was a traced zombie.
261 * Return true if it needs to be reaped with release_task().
262 * (We can't call release_task() here because we already hold tasklist_lock.)
264 * If it's a zombie, our attachedness prevented normal parent notification
265 * or self-reaping. Do notification now if it would have happened earlier.
266 * If it should reap itself, return true.
268 * If it's our own child, there is no notification to do. But if our normal
269 * children self-reap, then this child was prevented by ptrace and we must
270 * reap it now, in that case we must also wake up sub-threads sleeping in
271 * do_wait().
273 static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p)
275 __ptrace_unlink(p);
277 if (p->exit_state == EXIT_ZOMBIE) {
278 if (!task_detached(p) && thread_group_empty(p)) {
279 if (!same_thread_group(p->real_parent, tracer))
280 do_notify_parent(p, p->exit_signal);
281 else if (ignoring_children(tracer->sighand)) {
282 __wake_up_parent(p, tracer);
283 p->exit_signal = -1;
286 if (task_detached(p)) {
287 /* Mark it as in the process of being reaped. */
288 p->exit_state = EXIT_DEAD;
289 return true;
293 return false;
296 int ptrace_detach(struct task_struct *child, unsigned int data)
298 bool dead = false;
300 if (!valid_signal(data))
301 return -EIO;
303 /* Architecture-specific hardware disable .. */
304 ptrace_disable(child);
305 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
307 write_lock_irq(&tasklist_lock);
309 * This child can be already killed. Make sure de_thread() or
310 * our sub-thread doing do_wait() didn't do release_task() yet.
312 if (child->ptrace) {
313 child->exit_code = data;
314 dead = __ptrace_detach(current, child);
315 if (!child->exit_state)
316 wake_up_process(child);
318 write_unlock_irq(&tasklist_lock);
320 if (unlikely(dead))
321 release_task(child);
323 return 0;
327 * Detach all tasks we were using ptrace on.
329 void exit_ptrace(struct task_struct *tracer)
331 struct task_struct *p, *n;
332 LIST_HEAD(ptrace_dead);
334 write_lock_irq(&tasklist_lock);
335 list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) {
336 if (__ptrace_detach(tracer, p))
337 list_add(&p->ptrace_entry, &ptrace_dead);
339 write_unlock_irq(&tasklist_lock);
341 BUG_ON(!list_empty(&tracer->ptraced));
343 list_for_each_entry_safe(p, n, &ptrace_dead, ptrace_entry) {
344 list_del_init(&p->ptrace_entry);
345 release_task(p);
349 int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len)
351 int copied = 0;
353 while (len > 0) {
354 char buf[128];
355 int this_len, retval;
357 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
358 retval = access_process_vm(tsk, src, buf, this_len, 0);
359 if (!retval) {
360 if (copied)
361 break;
362 return -EIO;
364 if (copy_to_user(dst, buf, retval))
365 return -EFAULT;
366 copied += retval;
367 src += retval;
368 dst += retval;
369 len -= retval;
371 return copied;
374 int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len)
376 int copied = 0;
378 while (len > 0) {
379 char buf[128];
380 int this_len, retval;
382 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
383 if (copy_from_user(buf, src, this_len))
384 return -EFAULT;
385 retval = access_process_vm(tsk, dst, buf, this_len, 1);
386 if (!retval) {
387 if (copied)
388 break;
389 return -EIO;
391 copied += retval;
392 src += retval;
393 dst += retval;
394 len -= retval;
396 return copied;
399 static int ptrace_setoptions(struct task_struct *child, long data)
401 child->ptrace &= ~PT_TRACE_MASK;
403 if (data & PTRACE_O_TRACESYSGOOD)
404 child->ptrace |= PT_TRACESYSGOOD;
406 if (data & PTRACE_O_TRACEFORK)
407 child->ptrace |= PT_TRACE_FORK;
409 if (data & PTRACE_O_TRACEVFORK)
410 child->ptrace |= PT_TRACE_VFORK;
412 if (data & PTRACE_O_TRACECLONE)
413 child->ptrace |= PT_TRACE_CLONE;
415 if (data & PTRACE_O_TRACEEXEC)
416 child->ptrace |= PT_TRACE_EXEC;
418 if (data & PTRACE_O_TRACEVFORKDONE)
419 child->ptrace |= PT_TRACE_VFORK_DONE;
421 if (data & PTRACE_O_TRACEEXIT)
422 child->ptrace |= PT_TRACE_EXIT;
424 return (data & ~PTRACE_O_MASK) ? -EINVAL : 0;
427 static int ptrace_getsiginfo(struct task_struct *child, siginfo_t *info)
429 unsigned long flags;
430 int error = -ESRCH;
432 if (lock_task_sighand(child, &flags)) {
433 error = -EINVAL;
434 if (likely(child->last_siginfo != NULL)) {
435 *info = *child->last_siginfo;
436 error = 0;
438 unlock_task_sighand(child, &flags);
440 return error;
443 static int ptrace_setsiginfo(struct task_struct *child, const siginfo_t *info)
445 unsigned long flags;
446 int error = -ESRCH;
448 if (lock_task_sighand(child, &flags)) {
449 error = -EINVAL;
450 if (likely(child->last_siginfo != NULL)) {
451 *child->last_siginfo = *info;
452 error = 0;
454 unlock_task_sighand(child, &flags);
456 return error;
460 #ifdef PTRACE_SINGLESTEP
461 #define is_singlestep(request) ((request) == PTRACE_SINGLESTEP)
462 #else
463 #define is_singlestep(request) 0
464 #endif
466 #ifdef PTRACE_SINGLEBLOCK
467 #define is_singleblock(request) ((request) == PTRACE_SINGLEBLOCK)
468 #else
469 #define is_singleblock(request) 0
470 #endif
472 #ifdef PTRACE_SYSEMU
473 #define is_sysemu_singlestep(request) ((request) == PTRACE_SYSEMU_SINGLESTEP)
474 #else
475 #define is_sysemu_singlestep(request) 0
476 #endif
478 static int ptrace_resume(struct task_struct *child, long request, long data)
480 if (!valid_signal(data))
481 return -EIO;
483 if (request == PTRACE_SYSCALL)
484 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
485 else
486 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
488 #ifdef TIF_SYSCALL_EMU
489 if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP)
490 set_tsk_thread_flag(child, TIF_SYSCALL_EMU);
491 else
492 clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
493 #endif
495 if (is_singleblock(request)) {
496 if (unlikely(!arch_has_block_step()))
497 return -EIO;
498 user_enable_block_step(child);
499 } else if (is_singlestep(request) || is_sysemu_singlestep(request)) {
500 if (unlikely(!arch_has_single_step()))
501 return -EIO;
502 user_enable_single_step(child);
503 } else {
504 user_disable_single_step(child);
507 child->exit_code = data;
508 wake_up_process(child);
510 return 0;
513 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
515 static const struct user_regset *
516 find_regset(const struct user_regset_view *view, unsigned int type)
518 const struct user_regset *regset;
519 int n;
521 for (n = 0; n < view->n; ++n) {
522 regset = view->regsets + n;
523 if (regset->core_note_type == type)
524 return regset;
527 return NULL;
530 static int ptrace_regset(struct task_struct *task, int req, unsigned int type,
531 struct iovec *kiov)
533 const struct user_regset_view *view = task_user_regset_view(task);
534 const struct user_regset *regset = find_regset(view, type);
535 int regset_no;
537 if (!regset || (kiov->iov_len % regset->size) != 0)
538 return -EINVAL;
540 regset_no = regset - view->regsets;
541 kiov->iov_len = min(kiov->iov_len,
542 (__kernel_size_t) (regset->n * regset->size));
544 if (req == PTRACE_GETREGSET)
545 return copy_regset_to_user(task, view, regset_no, 0,
546 kiov->iov_len, kiov->iov_base);
547 else
548 return copy_regset_from_user(task, view, regset_no, 0,
549 kiov->iov_len, kiov->iov_base);
552 #endif
554 int ptrace_request(struct task_struct *child, long request,
555 long addr, long data)
557 int ret = -EIO;
558 siginfo_t siginfo;
560 switch (request) {
561 case PTRACE_PEEKTEXT:
562 case PTRACE_PEEKDATA:
563 return generic_ptrace_peekdata(child, addr, data);
564 case PTRACE_POKETEXT:
565 case PTRACE_POKEDATA:
566 return generic_ptrace_pokedata(child, addr, data);
568 #ifdef PTRACE_OLDSETOPTIONS
569 case PTRACE_OLDSETOPTIONS:
570 #endif
571 case PTRACE_SETOPTIONS:
572 ret = ptrace_setoptions(child, data);
573 break;
574 case PTRACE_GETEVENTMSG:
575 ret = put_user(child->ptrace_message, (unsigned long __user *) data);
576 break;
578 case PTRACE_GETSIGINFO:
579 ret = ptrace_getsiginfo(child, &siginfo);
580 if (!ret)
581 ret = copy_siginfo_to_user((siginfo_t __user *) data,
582 &siginfo);
583 break;
585 case PTRACE_SETSIGINFO:
586 if (copy_from_user(&siginfo, (siginfo_t __user *) data,
587 sizeof siginfo))
588 ret = -EFAULT;
589 else
590 ret = ptrace_setsiginfo(child, &siginfo);
591 break;
593 case PTRACE_DETACH: /* detach a process that was attached. */
594 ret = ptrace_detach(child, data);
595 break;
597 #ifdef CONFIG_BINFMT_ELF_FDPIC
598 case PTRACE_GETFDPIC: {
599 struct mm_struct *mm = get_task_mm(child);
600 unsigned long tmp = 0;
602 ret = -ESRCH;
603 if (!mm)
604 break;
606 switch (addr) {
607 case PTRACE_GETFDPIC_EXEC:
608 tmp = mm->context.exec_fdpic_loadmap;
609 break;
610 case PTRACE_GETFDPIC_INTERP:
611 tmp = mm->context.interp_fdpic_loadmap;
612 break;
613 default:
614 break;
616 mmput(mm);
618 ret = put_user(tmp, (unsigned long __user *) data);
619 break;
621 #endif
623 #ifdef PTRACE_SINGLESTEP
624 case PTRACE_SINGLESTEP:
625 #endif
626 #ifdef PTRACE_SINGLEBLOCK
627 case PTRACE_SINGLEBLOCK:
628 #endif
629 #ifdef PTRACE_SYSEMU
630 case PTRACE_SYSEMU:
631 case PTRACE_SYSEMU_SINGLESTEP:
632 #endif
633 case PTRACE_SYSCALL:
634 case PTRACE_CONT:
635 return ptrace_resume(child, request, data);
637 case PTRACE_KILL:
638 if (child->exit_state) /* already dead */
639 return 0;
640 return ptrace_resume(child, request, SIGKILL);
642 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
643 case PTRACE_GETREGSET:
644 case PTRACE_SETREGSET:
646 struct iovec kiov;
647 struct iovec __user *uiov = (struct iovec __user *) data;
649 if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov)))
650 return -EFAULT;
652 if (__get_user(kiov.iov_base, &uiov->iov_base) ||
653 __get_user(kiov.iov_len, &uiov->iov_len))
654 return -EFAULT;
656 ret = ptrace_regset(child, request, addr, &kiov);
657 if (!ret)
658 ret = __put_user(kiov.iov_len, &uiov->iov_len);
659 break;
661 #endif
662 default:
663 break;
666 return ret;
669 static struct task_struct *ptrace_get_task_struct(pid_t pid)
671 struct task_struct *child;
673 rcu_read_lock();
674 child = find_task_by_vpid(pid);
675 if (child)
676 get_task_struct(child);
677 rcu_read_unlock();
679 if (!child)
680 return ERR_PTR(-ESRCH);
681 return child;
684 #ifndef arch_ptrace_attach
685 #define arch_ptrace_attach(child) do { } while (0)
686 #endif
688 SYSCALL_DEFINE4(ptrace, long, request, long, pid, long, addr, long, data)
690 struct task_struct *child;
691 long ret;
693 if (request == PTRACE_TRACEME) {
694 ret = ptrace_traceme();
695 if (!ret)
696 arch_ptrace_attach(current);
697 goto out;
700 child = ptrace_get_task_struct(pid);
701 if (IS_ERR(child)) {
702 ret = PTR_ERR(child);
703 goto out;
706 if (request == PTRACE_ATTACH) {
707 ret = ptrace_attach(child);
709 * Some architectures need to do book-keeping after
710 * a ptrace attach.
712 if (!ret)
713 arch_ptrace_attach(child);
714 goto out_put_task_struct;
717 ret = ptrace_check_attach(child, request == PTRACE_KILL);
718 if (ret < 0)
719 goto out_put_task_struct;
721 ret = arch_ptrace(child, request, addr, data);
723 out_put_task_struct:
724 put_task_struct(child);
725 out:
726 return ret;
729 int generic_ptrace_peekdata(struct task_struct *tsk, long addr, long data)
731 unsigned long tmp;
732 int copied;
734 copied = access_process_vm(tsk, addr, &tmp, sizeof(tmp), 0);
735 if (copied != sizeof(tmp))
736 return -EIO;
737 return put_user(tmp, (unsigned long __user *)data);
740 int generic_ptrace_pokedata(struct task_struct *tsk, long addr, long data)
742 int copied;
744 copied = access_process_vm(tsk, addr, &data, sizeof(data), 1);
745 return (copied == sizeof(data)) ? 0 : -EIO;
748 #if defined CONFIG_COMPAT
749 #include <linux/compat.h>
751 int compat_ptrace_request(struct task_struct *child, compat_long_t request,
752 compat_ulong_t addr, compat_ulong_t data)
754 compat_ulong_t __user *datap = compat_ptr(data);
755 compat_ulong_t word;
756 siginfo_t siginfo;
757 int ret;
759 switch (request) {
760 case PTRACE_PEEKTEXT:
761 case PTRACE_PEEKDATA:
762 ret = access_process_vm(child, addr, &word, sizeof(word), 0);
763 if (ret != sizeof(word))
764 ret = -EIO;
765 else
766 ret = put_user(word, datap);
767 break;
769 case PTRACE_POKETEXT:
770 case PTRACE_POKEDATA:
771 ret = access_process_vm(child, addr, &data, sizeof(data), 1);
772 ret = (ret != sizeof(data) ? -EIO : 0);
773 break;
775 case PTRACE_GETEVENTMSG:
776 ret = put_user((compat_ulong_t) child->ptrace_message, datap);
777 break;
779 case PTRACE_GETSIGINFO:
780 ret = ptrace_getsiginfo(child, &siginfo);
781 if (!ret)
782 ret = copy_siginfo_to_user32(
783 (struct compat_siginfo __user *) datap,
784 &siginfo);
785 break;
787 case PTRACE_SETSIGINFO:
788 memset(&siginfo, 0, sizeof siginfo);
789 if (copy_siginfo_from_user32(
790 &siginfo, (struct compat_siginfo __user *) datap))
791 ret = -EFAULT;
792 else
793 ret = ptrace_setsiginfo(child, &siginfo);
794 break;
795 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
796 case PTRACE_GETREGSET:
797 case PTRACE_SETREGSET:
799 struct iovec kiov;
800 struct compat_iovec __user *uiov =
801 (struct compat_iovec __user *) datap;
802 compat_uptr_t ptr;
803 compat_size_t len;
805 if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov)))
806 return -EFAULT;
808 if (__get_user(ptr, &uiov->iov_base) ||
809 __get_user(len, &uiov->iov_len))
810 return -EFAULT;
812 kiov.iov_base = compat_ptr(ptr);
813 kiov.iov_len = len;
815 ret = ptrace_regset(child, request, addr, &kiov);
816 if (!ret)
817 ret = __put_user(kiov.iov_len, &uiov->iov_len);
818 break;
820 #endif
822 default:
823 ret = ptrace_request(child, request, addr, data);
826 return ret;
829 asmlinkage long compat_sys_ptrace(compat_long_t request, compat_long_t pid,
830 compat_long_t addr, compat_long_t data)
832 struct task_struct *child;
833 long ret;
835 if (request == PTRACE_TRACEME) {
836 ret = ptrace_traceme();
837 goto out;
840 child = ptrace_get_task_struct(pid);
841 if (IS_ERR(child)) {
842 ret = PTR_ERR(child);
843 goto out;
846 if (request == PTRACE_ATTACH) {
847 ret = ptrace_attach(child);
849 * Some architectures need to do book-keeping after
850 * a ptrace attach.
852 if (!ret)
853 arch_ptrace_attach(child);
854 goto out_put_task_struct;
857 ret = ptrace_check_attach(child, request == PTRACE_KILL);
858 if (!ret)
859 ret = compat_arch_ptrace(child, request, addr, data);
861 out_put_task_struct:
862 put_task_struct(child);
863 out:
864 return ret;
866 #endif /* CONFIG_COMPAT */