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[pohmelfs.git] / kernel / ptrace.c
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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/export.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>
25 #include <linux/hw_breakpoint.h>
26 #include <linux/cn_proc.h>
29 static int ptrace_trapping_sleep_fn(void *flags)
31 schedule();
32 return 0;
36 * ptrace a task: make the debugger its new parent and
37 * move it to the ptrace list.
39 * Must be called with the tasklist lock write-held.
41 void __ptrace_link(struct task_struct *child, struct task_struct *new_parent)
43 BUG_ON(!list_empty(&child->ptrace_entry));
44 list_add(&child->ptrace_entry, &new_parent->ptraced);
45 child->parent = new_parent;
48 /**
49 * __ptrace_unlink - unlink ptracee and restore its execution state
50 * @child: ptracee to be unlinked
52 * Remove @child from the ptrace list, move it back to the original parent,
53 * and restore the execution state so that it conforms to the group stop
54 * state.
56 * Unlinking can happen via two paths - explicit PTRACE_DETACH or ptracer
57 * exiting. For PTRACE_DETACH, unless the ptracee has been killed between
58 * ptrace_check_attach() and here, it's guaranteed to be in TASK_TRACED.
59 * If the ptracer is exiting, the ptracee can be in any state.
61 * After detach, the ptracee should be in a state which conforms to the
62 * group stop. If the group is stopped or in the process of stopping, the
63 * ptracee should be put into TASK_STOPPED; otherwise, it should be woken
64 * up from TASK_TRACED.
66 * If the ptracee is in TASK_TRACED and needs to be moved to TASK_STOPPED,
67 * it goes through TRACED -> RUNNING -> STOPPED transition which is similar
68 * to but in the opposite direction of what happens while attaching to a
69 * stopped task. However, in this direction, the intermediate RUNNING
70 * state is not hidden even from the current ptracer and if it immediately
71 * re-attaches and performs a WNOHANG wait(2), it may fail.
73 * CONTEXT:
74 * write_lock_irq(tasklist_lock)
76 void __ptrace_unlink(struct task_struct *child)
78 BUG_ON(!child->ptrace);
80 child->ptrace = 0;
81 child->parent = child->real_parent;
82 list_del_init(&child->ptrace_entry);
84 spin_lock(&child->sighand->siglock);
87 * Clear all pending traps and TRAPPING. TRAPPING should be
88 * cleared regardless of JOBCTL_STOP_PENDING. Do it explicitly.
90 task_clear_jobctl_pending(child, JOBCTL_TRAP_MASK);
91 task_clear_jobctl_trapping(child);
94 * Reinstate JOBCTL_STOP_PENDING if group stop is in effect and
95 * @child isn't dead.
97 if (!(child->flags & PF_EXITING) &&
98 (child->signal->flags & SIGNAL_STOP_STOPPED ||
99 child->signal->group_stop_count)) {
100 child->jobctl |= JOBCTL_STOP_PENDING;
103 * This is only possible if this thread was cloned by the
104 * traced task running in the stopped group, set the signal
105 * for the future reports.
106 * FIXME: we should change ptrace_init_task() to handle this
107 * case.
109 if (!(child->jobctl & JOBCTL_STOP_SIGMASK))
110 child->jobctl |= SIGSTOP;
114 * If transition to TASK_STOPPED is pending or in TASK_TRACED, kick
115 * @child in the butt. Note that @resume should be used iff @child
116 * is in TASK_TRACED; otherwise, we might unduly disrupt
117 * TASK_KILLABLE sleeps.
119 if (child->jobctl & JOBCTL_STOP_PENDING || task_is_traced(child))
120 signal_wake_up(child, task_is_traced(child));
122 spin_unlock(&child->sighand->siglock);
126 * ptrace_check_attach - check whether ptracee is ready for ptrace operation
127 * @child: ptracee to check for
128 * @ignore_state: don't check whether @child is currently %TASK_TRACED
130 * Check whether @child is being ptraced by %current and ready for further
131 * ptrace operations. If @ignore_state is %false, @child also should be in
132 * %TASK_TRACED state and on return the child is guaranteed to be traced
133 * and not executing. If @ignore_state is %true, @child can be in any
134 * state.
136 * CONTEXT:
137 * Grabs and releases tasklist_lock and @child->sighand->siglock.
139 * RETURNS:
140 * 0 on success, -ESRCH if %child is not ready.
142 int ptrace_check_attach(struct task_struct *child, bool ignore_state)
144 int ret = -ESRCH;
147 * We take the read lock around doing both checks to close a
148 * possible race where someone else was tracing our child and
149 * detached between these two checks. After this locked check,
150 * we are sure that this is our traced child and that can only
151 * be changed by us so it's not changing right after this.
153 read_lock(&tasklist_lock);
154 if ((child->ptrace & PT_PTRACED) && child->parent == current) {
156 * child->sighand can't be NULL, release_task()
157 * does ptrace_unlink() before __exit_signal().
159 spin_lock_irq(&child->sighand->siglock);
160 WARN_ON_ONCE(task_is_stopped(child));
161 if (ignore_state || (task_is_traced(child) &&
162 !(child->jobctl & JOBCTL_LISTENING)))
163 ret = 0;
164 spin_unlock_irq(&child->sighand->siglock);
166 read_unlock(&tasklist_lock);
168 if (!ret && !ignore_state)
169 ret = wait_task_inactive(child, TASK_TRACED) ? 0 : -ESRCH;
171 /* All systems go.. */
172 return ret;
175 static int ptrace_has_cap(struct user_namespace *ns, unsigned int mode)
177 if (mode & PTRACE_MODE_NOAUDIT)
178 return has_ns_capability_noaudit(current, ns, CAP_SYS_PTRACE);
179 else
180 return has_ns_capability(current, ns, CAP_SYS_PTRACE);
183 int __ptrace_may_access(struct task_struct *task, unsigned int mode)
185 const struct cred *cred = current_cred(), *tcred;
187 /* May we inspect the given task?
188 * This check is used both for attaching with ptrace
189 * and for allowing access to sensitive information in /proc.
191 * ptrace_attach denies several cases that /proc allows
192 * because setting up the necessary parent/child relationship
193 * or halting the specified task is impossible.
195 int dumpable = 0;
196 /* Don't let security modules deny introspection */
197 if (task == current)
198 return 0;
199 rcu_read_lock();
200 tcred = __task_cred(task);
201 if (cred->user->user_ns == tcred->user->user_ns &&
202 (cred->uid == tcred->euid &&
203 cred->uid == tcred->suid &&
204 cred->uid == tcred->uid &&
205 cred->gid == tcred->egid &&
206 cred->gid == tcred->sgid &&
207 cred->gid == tcred->gid))
208 goto ok;
209 if (ptrace_has_cap(tcred->user->user_ns, mode))
210 goto ok;
211 rcu_read_unlock();
212 return -EPERM;
214 rcu_read_unlock();
215 smp_rmb();
216 if (task->mm)
217 dumpable = get_dumpable(task->mm);
218 if (!dumpable && !ptrace_has_cap(task_user_ns(task), mode))
219 return -EPERM;
221 return security_ptrace_access_check(task, mode);
224 bool ptrace_may_access(struct task_struct *task, unsigned int mode)
226 int err;
227 task_lock(task);
228 err = __ptrace_may_access(task, mode);
229 task_unlock(task);
230 return !err;
233 static int ptrace_attach(struct task_struct *task, long request,
234 unsigned long flags)
236 bool seize = (request == PTRACE_SEIZE);
237 int retval;
240 * SEIZE will enable new ptrace behaviors which will be implemented
241 * gradually. SEIZE_DEVEL is used to prevent applications
242 * expecting full SEIZE behaviors trapping on kernel commits which
243 * are still in the process of implementing them.
245 * Only test programs for new ptrace behaviors being implemented
246 * should set SEIZE_DEVEL. If unset, SEIZE will fail with -EIO.
248 * Once SEIZE behaviors are completely implemented, this flag and
249 * the following test will be removed.
251 retval = -EIO;
252 if (seize && !(flags & PTRACE_SEIZE_DEVEL))
253 goto out;
255 audit_ptrace(task);
257 retval = -EPERM;
258 if (unlikely(task->flags & PF_KTHREAD))
259 goto out;
260 if (same_thread_group(task, current))
261 goto out;
264 * Protect exec's credential calculations against our interference;
265 * interference; SUID, SGID and LSM creds get determined differently
266 * under ptrace.
268 retval = -ERESTARTNOINTR;
269 if (mutex_lock_interruptible(&task->signal->cred_guard_mutex))
270 goto out;
272 task_lock(task);
273 retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH);
274 task_unlock(task);
275 if (retval)
276 goto unlock_creds;
278 write_lock_irq(&tasklist_lock);
279 retval = -EPERM;
280 if (unlikely(task->exit_state))
281 goto unlock_tasklist;
282 if (task->ptrace)
283 goto unlock_tasklist;
285 task->ptrace = PT_PTRACED;
286 if (seize)
287 task->ptrace |= PT_SEIZED;
288 if (ns_capable(task_user_ns(task), CAP_SYS_PTRACE))
289 task->ptrace |= PT_PTRACE_CAP;
291 __ptrace_link(task, current);
293 /* SEIZE doesn't trap tracee on attach */
294 if (!seize)
295 send_sig_info(SIGSTOP, SEND_SIG_FORCED, task);
297 spin_lock(&task->sighand->siglock);
300 * If the task is already STOPPED, set JOBCTL_TRAP_STOP and
301 * TRAPPING, and kick it so that it transits to TRACED. TRAPPING
302 * will be cleared if the child completes the transition or any
303 * event which clears the group stop states happens. We'll wait
304 * for the transition to complete before returning from this
305 * function.
307 * This hides STOPPED -> RUNNING -> TRACED transition from the
308 * attaching thread but a different thread in the same group can
309 * still observe the transient RUNNING state. IOW, if another
310 * thread's WNOHANG wait(2) on the stopped tracee races against
311 * ATTACH, the wait(2) may fail due to the transient RUNNING.
313 * The following task_is_stopped() test is safe as both transitions
314 * in and out of STOPPED are protected by siglock.
316 if (task_is_stopped(task) &&
317 task_set_jobctl_pending(task, JOBCTL_TRAP_STOP | JOBCTL_TRAPPING))
318 signal_wake_up(task, 1);
320 spin_unlock(&task->sighand->siglock);
322 retval = 0;
323 unlock_tasklist:
324 write_unlock_irq(&tasklist_lock);
325 unlock_creds:
326 mutex_unlock(&task->signal->cred_guard_mutex);
327 out:
328 if (!retval) {
329 wait_on_bit(&task->jobctl, JOBCTL_TRAPPING_BIT,
330 ptrace_trapping_sleep_fn, TASK_UNINTERRUPTIBLE);
331 proc_ptrace_connector(task, PTRACE_ATTACH);
334 return retval;
338 * ptrace_traceme -- helper for PTRACE_TRACEME
340 * Performs checks and sets PT_PTRACED.
341 * Should be used by all ptrace implementations for PTRACE_TRACEME.
343 static int ptrace_traceme(void)
345 int ret = -EPERM;
347 write_lock_irq(&tasklist_lock);
348 /* Are we already being traced? */
349 if (!current->ptrace) {
350 ret = security_ptrace_traceme(current->parent);
352 * Check PF_EXITING to ensure ->real_parent has not passed
353 * exit_ptrace(). Otherwise we don't report the error but
354 * pretend ->real_parent untraces us right after return.
356 if (!ret && !(current->real_parent->flags & PF_EXITING)) {
357 current->ptrace = PT_PTRACED;
358 __ptrace_link(current, current->real_parent);
361 write_unlock_irq(&tasklist_lock);
363 return ret;
367 * Called with irqs disabled, returns true if childs should reap themselves.
369 static int ignoring_children(struct sighand_struct *sigh)
371 int ret;
372 spin_lock(&sigh->siglock);
373 ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) ||
374 (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT);
375 spin_unlock(&sigh->siglock);
376 return ret;
380 * Called with tasklist_lock held for writing.
381 * Unlink a traced task, and clean it up if it was a traced zombie.
382 * Return true if it needs to be reaped with release_task().
383 * (We can't call release_task() here because we already hold tasklist_lock.)
385 * If it's a zombie, our attachedness prevented normal parent notification
386 * or self-reaping. Do notification now if it would have happened earlier.
387 * If it should reap itself, return true.
389 * If it's our own child, there is no notification to do. But if our normal
390 * children self-reap, then this child was prevented by ptrace and we must
391 * reap it now, in that case we must also wake up sub-threads sleeping in
392 * do_wait().
394 static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p)
396 bool dead;
398 __ptrace_unlink(p);
400 if (p->exit_state != EXIT_ZOMBIE)
401 return false;
403 dead = !thread_group_leader(p);
405 if (!dead && thread_group_empty(p)) {
406 if (!same_thread_group(p->real_parent, tracer))
407 dead = do_notify_parent(p, p->exit_signal);
408 else if (ignoring_children(tracer->sighand)) {
409 __wake_up_parent(p, tracer);
410 dead = true;
413 /* Mark it as in the process of being reaped. */
414 if (dead)
415 p->exit_state = EXIT_DEAD;
416 return dead;
419 static int ptrace_detach(struct task_struct *child, unsigned int data)
421 bool dead = false;
423 if (!valid_signal(data))
424 return -EIO;
426 /* Architecture-specific hardware disable .. */
427 ptrace_disable(child);
428 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
430 write_lock_irq(&tasklist_lock);
432 * This child can be already killed. Make sure de_thread() or
433 * our sub-thread doing do_wait() didn't do release_task() yet.
435 if (child->ptrace) {
436 child->exit_code = data;
437 dead = __ptrace_detach(current, child);
439 write_unlock_irq(&tasklist_lock);
441 proc_ptrace_connector(child, PTRACE_DETACH);
442 if (unlikely(dead))
443 release_task(child);
445 return 0;
449 * Detach all tasks we were using ptrace on. Called with tasklist held
450 * for writing, and returns with it held too. But note it can release
451 * and reacquire the lock.
453 void exit_ptrace(struct task_struct *tracer)
454 __releases(&tasklist_lock)
455 __acquires(&tasklist_lock)
457 struct task_struct *p, *n;
458 LIST_HEAD(ptrace_dead);
460 if (likely(list_empty(&tracer->ptraced)))
461 return;
463 list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) {
464 if (__ptrace_detach(tracer, p))
465 list_add(&p->ptrace_entry, &ptrace_dead);
468 write_unlock_irq(&tasklist_lock);
469 BUG_ON(!list_empty(&tracer->ptraced));
471 list_for_each_entry_safe(p, n, &ptrace_dead, ptrace_entry) {
472 list_del_init(&p->ptrace_entry);
473 release_task(p);
476 write_lock_irq(&tasklist_lock);
479 int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len)
481 int copied = 0;
483 while (len > 0) {
484 char buf[128];
485 int this_len, retval;
487 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
488 retval = access_process_vm(tsk, src, buf, this_len, 0);
489 if (!retval) {
490 if (copied)
491 break;
492 return -EIO;
494 if (copy_to_user(dst, buf, retval))
495 return -EFAULT;
496 copied += retval;
497 src += retval;
498 dst += retval;
499 len -= retval;
501 return copied;
504 int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len)
506 int copied = 0;
508 while (len > 0) {
509 char buf[128];
510 int this_len, retval;
512 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
513 if (copy_from_user(buf, src, this_len))
514 return -EFAULT;
515 retval = access_process_vm(tsk, dst, buf, this_len, 1);
516 if (!retval) {
517 if (copied)
518 break;
519 return -EIO;
521 copied += retval;
522 src += retval;
523 dst += retval;
524 len -= retval;
526 return copied;
529 static int ptrace_setoptions(struct task_struct *child, unsigned long data)
531 child->ptrace &= ~PT_TRACE_MASK;
533 if (data & PTRACE_O_TRACESYSGOOD)
534 child->ptrace |= PT_TRACESYSGOOD;
536 if (data & PTRACE_O_TRACEFORK)
537 child->ptrace |= PT_TRACE_FORK;
539 if (data & PTRACE_O_TRACEVFORK)
540 child->ptrace |= PT_TRACE_VFORK;
542 if (data & PTRACE_O_TRACECLONE)
543 child->ptrace |= PT_TRACE_CLONE;
545 if (data & PTRACE_O_TRACEEXEC)
546 child->ptrace |= PT_TRACE_EXEC;
548 if (data & PTRACE_O_TRACEVFORKDONE)
549 child->ptrace |= PT_TRACE_VFORK_DONE;
551 if (data & PTRACE_O_TRACEEXIT)
552 child->ptrace |= PT_TRACE_EXIT;
554 return (data & ~PTRACE_O_MASK) ? -EINVAL : 0;
557 static int ptrace_getsiginfo(struct task_struct *child, siginfo_t *info)
559 unsigned long flags;
560 int error = -ESRCH;
562 if (lock_task_sighand(child, &flags)) {
563 error = -EINVAL;
564 if (likely(child->last_siginfo != NULL)) {
565 *info = *child->last_siginfo;
566 error = 0;
568 unlock_task_sighand(child, &flags);
570 return error;
573 static int ptrace_setsiginfo(struct task_struct *child, const siginfo_t *info)
575 unsigned long flags;
576 int error = -ESRCH;
578 if (lock_task_sighand(child, &flags)) {
579 error = -EINVAL;
580 if (likely(child->last_siginfo != NULL)) {
581 *child->last_siginfo = *info;
582 error = 0;
584 unlock_task_sighand(child, &flags);
586 return error;
590 #ifdef PTRACE_SINGLESTEP
591 #define is_singlestep(request) ((request) == PTRACE_SINGLESTEP)
592 #else
593 #define is_singlestep(request) 0
594 #endif
596 #ifdef PTRACE_SINGLEBLOCK
597 #define is_singleblock(request) ((request) == PTRACE_SINGLEBLOCK)
598 #else
599 #define is_singleblock(request) 0
600 #endif
602 #ifdef PTRACE_SYSEMU
603 #define is_sysemu_singlestep(request) ((request) == PTRACE_SYSEMU_SINGLESTEP)
604 #else
605 #define is_sysemu_singlestep(request) 0
606 #endif
608 static int ptrace_resume(struct task_struct *child, long request,
609 unsigned long data)
611 if (!valid_signal(data))
612 return -EIO;
614 if (request == PTRACE_SYSCALL)
615 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
616 else
617 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
619 #ifdef TIF_SYSCALL_EMU
620 if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP)
621 set_tsk_thread_flag(child, TIF_SYSCALL_EMU);
622 else
623 clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
624 #endif
626 if (is_singleblock(request)) {
627 if (unlikely(!arch_has_block_step()))
628 return -EIO;
629 user_enable_block_step(child);
630 } else if (is_singlestep(request) || is_sysemu_singlestep(request)) {
631 if (unlikely(!arch_has_single_step()))
632 return -EIO;
633 user_enable_single_step(child);
634 } else {
635 user_disable_single_step(child);
638 child->exit_code = data;
639 wake_up_state(child, __TASK_TRACED);
641 return 0;
644 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
646 static const struct user_regset *
647 find_regset(const struct user_regset_view *view, unsigned int type)
649 const struct user_regset *regset;
650 int n;
652 for (n = 0; n < view->n; ++n) {
653 regset = view->regsets + n;
654 if (regset->core_note_type == type)
655 return regset;
658 return NULL;
661 static int ptrace_regset(struct task_struct *task, int req, unsigned int type,
662 struct iovec *kiov)
664 const struct user_regset_view *view = task_user_regset_view(task);
665 const struct user_regset *regset = find_regset(view, type);
666 int regset_no;
668 if (!regset || (kiov->iov_len % regset->size) != 0)
669 return -EINVAL;
671 regset_no = regset - view->regsets;
672 kiov->iov_len = min(kiov->iov_len,
673 (__kernel_size_t) (regset->n * regset->size));
675 if (req == PTRACE_GETREGSET)
676 return copy_regset_to_user(task, view, regset_no, 0,
677 kiov->iov_len, kiov->iov_base);
678 else
679 return copy_regset_from_user(task, view, regset_no, 0,
680 kiov->iov_len, kiov->iov_base);
683 #endif
685 int ptrace_request(struct task_struct *child, long request,
686 unsigned long addr, unsigned long data)
688 bool seized = child->ptrace & PT_SEIZED;
689 int ret = -EIO;
690 siginfo_t siginfo, *si;
691 void __user *datavp = (void __user *) data;
692 unsigned long __user *datalp = datavp;
693 unsigned long flags;
695 switch (request) {
696 case PTRACE_PEEKTEXT:
697 case PTRACE_PEEKDATA:
698 return generic_ptrace_peekdata(child, addr, data);
699 case PTRACE_POKETEXT:
700 case PTRACE_POKEDATA:
701 return generic_ptrace_pokedata(child, addr, data);
703 #ifdef PTRACE_OLDSETOPTIONS
704 case PTRACE_OLDSETOPTIONS:
705 #endif
706 case PTRACE_SETOPTIONS:
707 ret = ptrace_setoptions(child, data);
708 break;
709 case PTRACE_GETEVENTMSG:
710 ret = put_user(child->ptrace_message, datalp);
711 break;
713 case PTRACE_GETSIGINFO:
714 ret = ptrace_getsiginfo(child, &siginfo);
715 if (!ret)
716 ret = copy_siginfo_to_user(datavp, &siginfo);
717 break;
719 case PTRACE_SETSIGINFO:
720 if (copy_from_user(&siginfo, datavp, sizeof siginfo))
721 ret = -EFAULT;
722 else
723 ret = ptrace_setsiginfo(child, &siginfo);
724 break;
726 case PTRACE_INTERRUPT:
728 * Stop tracee without any side-effect on signal or job
729 * control. At least one trap is guaranteed to happen
730 * after this request. If @child is already trapped, the
731 * current trap is not disturbed and another trap will
732 * happen after the current trap is ended with PTRACE_CONT.
734 * The actual trap might not be PTRACE_EVENT_STOP trap but
735 * the pending condition is cleared regardless.
737 if (unlikely(!seized || !lock_task_sighand(child, &flags)))
738 break;
741 * INTERRUPT doesn't disturb existing trap sans one
742 * exception. If ptracer issued LISTEN for the current
743 * STOP, this INTERRUPT should clear LISTEN and re-trap
744 * tracee into STOP.
746 if (likely(task_set_jobctl_pending(child, JOBCTL_TRAP_STOP)))
747 signal_wake_up(child, child->jobctl & JOBCTL_LISTENING);
749 unlock_task_sighand(child, &flags);
750 ret = 0;
751 break;
753 case PTRACE_LISTEN:
755 * Listen for events. Tracee must be in STOP. It's not
756 * resumed per-se but is not considered to be in TRACED by
757 * wait(2) or ptrace(2). If an async event (e.g. group
758 * stop state change) happens, tracee will enter STOP trap
759 * again. Alternatively, ptracer can issue INTERRUPT to
760 * finish listening and re-trap tracee into STOP.
762 if (unlikely(!seized || !lock_task_sighand(child, &flags)))
763 break;
765 si = child->last_siginfo;
766 if (likely(si && (si->si_code >> 8) == PTRACE_EVENT_STOP)) {
767 child->jobctl |= JOBCTL_LISTENING;
769 * If NOTIFY is set, it means event happened between
770 * start of this trap and now. Trigger re-trap.
772 if (child->jobctl & JOBCTL_TRAP_NOTIFY)
773 signal_wake_up(child, true);
774 ret = 0;
776 unlock_task_sighand(child, &flags);
777 break;
779 case PTRACE_DETACH: /* detach a process that was attached. */
780 ret = ptrace_detach(child, data);
781 break;
783 #ifdef CONFIG_BINFMT_ELF_FDPIC
784 case PTRACE_GETFDPIC: {
785 struct mm_struct *mm = get_task_mm(child);
786 unsigned long tmp = 0;
788 ret = -ESRCH;
789 if (!mm)
790 break;
792 switch (addr) {
793 case PTRACE_GETFDPIC_EXEC:
794 tmp = mm->context.exec_fdpic_loadmap;
795 break;
796 case PTRACE_GETFDPIC_INTERP:
797 tmp = mm->context.interp_fdpic_loadmap;
798 break;
799 default:
800 break;
802 mmput(mm);
804 ret = put_user(tmp, datalp);
805 break;
807 #endif
809 #ifdef PTRACE_SINGLESTEP
810 case PTRACE_SINGLESTEP:
811 #endif
812 #ifdef PTRACE_SINGLEBLOCK
813 case PTRACE_SINGLEBLOCK:
814 #endif
815 #ifdef PTRACE_SYSEMU
816 case PTRACE_SYSEMU:
817 case PTRACE_SYSEMU_SINGLESTEP:
818 #endif
819 case PTRACE_SYSCALL:
820 case PTRACE_CONT:
821 return ptrace_resume(child, request, data);
823 case PTRACE_KILL:
824 if (child->exit_state) /* already dead */
825 return 0;
826 return ptrace_resume(child, request, SIGKILL);
828 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
829 case PTRACE_GETREGSET:
830 case PTRACE_SETREGSET:
832 struct iovec kiov;
833 struct iovec __user *uiov = datavp;
835 if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov)))
836 return -EFAULT;
838 if (__get_user(kiov.iov_base, &uiov->iov_base) ||
839 __get_user(kiov.iov_len, &uiov->iov_len))
840 return -EFAULT;
842 ret = ptrace_regset(child, request, addr, &kiov);
843 if (!ret)
844 ret = __put_user(kiov.iov_len, &uiov->iov_len);
845 break;
847 #endif
848 default:
849 break;
852 return ret;
855 static struct task_struct *ptrace_get_task_struct(pid_t pid)
857 struct task_struct *child;
859 rcu_read_lock();
860 child = find_task_by_vpid(pid);
861 if (child)
862 get_task_struct(child);
863 rcu_read_unlock();
865 if (!child)
866 return ERR_PTR(-ESRCH);
867 return child;
870 #ifndef arch_ptrace_attach
871 #define arch_ptrace_attach(child) do { } while (0)
872 #endif
874 SYSCALL_DEFINE4(ptrace, long, request, long, pid, unsigned long, addr,
875 unsigned long, data)
877 struct task_struct *child;
878 long ret;
880 if (request == PTRACE_TRACEME) {
881 ret = ptrace_traceme();
882 if (!ret)
883 arch_ptrace_attach(current);
884 goto out;
887 child = ptrace_get_task_struct(pid);
888 if (IS_ERR(child)) {
889 ret = PTR_ERR(child);
890 goto out;
893 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
894 ret = ptrace_attach(child, request, data);
896 * Some architectures need to do book-keeping after
897 * a ptrace attach.
899 if (!ret)
900 arch_ptrace_attach(child);
901 goto out_put_task_struct;
904 ret = ptrace_check_attach(child, request == PTRACE_KILL ||
905 request == PTRACE_INTERRUPT);
906 if (ret < 0)
907 goto out_put_task_struct;
909 ret = arch_ptrace(child, request, addr, data);
911 out_put_task_struct:
912 put_task_struct(child);
913 out:
914 return ret;
917 int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
918 unsigned long data)
920 unsigned long tmp;
921 int copied;
923 copied = access_process_vm(tsk, addr, &tmp, sizeof(tmp), 0);
924 if (copied != sizeof(tmp))
925 return -EIO;
926 return put_user(tmp, (unsigned long __user *)data);
929 int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
930 unsigned long data)
932 int copied;
934 copied = access_process_vm(tsk, addr, &data, sizeof(data), 1);
935 return (copied == sizeof(data)) ? 0 : -EIO;
938 #if defined CONFIG_COMPAT
939 #include <linux/compat.h>
941 int compat_ptrace_request(struct task_struct *child, compat_long_t request,
942 compat_ulong_t addr, compat_ulong_t data)
944 compat_ulong_t __user *datap = compat_ptr(data);
945 compat_ulong_t word;
946 siginfo_t siginfo;
947 int ret;
949 switch (request) {
950 case PTRACE_PEEKTEXT:
951 case PTRACE_PEEKDATA:
952 ret = access_process_vm(child, addr, &word, sizeof(word), 0);
953 if (ret != sizeof(word))
954 ret = -EIO;
955 else
956 ret = put_user(word, datap);
957 break;
959 case PTRACE_POKETEXT:
960 case PTRACE_POKEDATA:
961 ret = access_process_vm(child, addr, &data, sizeof(data), 1);
962 ret = (ret != sizeof(data) ? -EIO : 0);
963 break;
965 case PTRACE_GETEVENTMSG:
966 ret = put_user((compat_ulong_t) child->ptrace_message, datap);
967 break;
969 case PTRACE_GETSIGINFO:
970 ret = ptrace_getsiginfo(child, &siginfo);
971 if (!ret)
972 ret = copy_siginfo_to_user32(
973 (struct compat_siginfo __user *) datap,
974 &siginfo);
975 break;
977 case PTRACE_SETSIGINFO:
978 memset(&siginfo, 0, sizeof siginfo);
979 if (copy_siginfo_from_user32(
980 &siginfo, (struct compat_siginfo __user *) datap))
981 ret = -EFAULT;
982 else
983 ret = ptrace_setsiginfo(child, &siginfo);
984 break;
985 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
986 case PTRACE_GETREGSET:
987 case PTRACE_SETREGSET:
989 struct iovec kiov;
990 struct compat_iovec __user *uiov =
991 (struct compat_iovec __user *) datap;
992 compat_uptr_t ptr;
993 compat_size_t len;
995 if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov)))
996 return -EFAULT;
998 if (__get_user(ptr, &uiov->iov_base) ||
999 __get_user(len, &uiov->iov_len))
1000 return -EFAULT;
1002 kiov.iov_base = compat_ptr(ptr);
1003 kiov.iov_len = len;
1005 ret = ptrace_regset(child, request, addr, &kiov);
1006 if (!ret)
1007 ret = __put_user(kiov.iov_len, &uiov->iov_len);
1008 break;
1010 #endif
1012 default:
1013 ret = ptrace_request(child, request, addr, data);
1016 return ret;
1019 asmlinkage long compat_sys_ptrace(compat_long_t request, compat_long_t pid,
1020 compat_long_t addr, compat_long_t data)
1022 struct task_struct *child;
1023 long ret;
1025 if (request == PTRACE_TRACEME) {
1026 ret = ptrace_traceme();
1027 goto out;
1030 child = ptrace_get_task_struct(pid);
1031 if (IS_ERR(child)) {
1032 ret = PTR_ERR(child);
1033 goto out;
1036 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
1037 ret = ptrace_attach(child, request, data);
1039 * Some architectures need to do book-keeping after
1040 * a ptrace attach.
1042 if (!ret)
1043 arch_ptrace_attach(child);
1044 goto out_put_task_struct;
1047 ret = ptrace_check_attach(child, request == PTRACE_KILL ||
1048 request == PTRACE_INTERRUPT);
1049 if (!ret)
1050 ret = compat_arch_ptrace(child, request, addr, data);
1052 out_put_task_struct:
1053 put_task_struct(child);
1054 out:
1055 return ret;
1057 #endif /* CONFIG_COMPAT */
1059 #ifdef CONFIG_HAVE_HW_BREAKPOINT
1060 int ptrace_get_breakpoints(struct task_struct *tsk)
1062 if (atomic_inc_not_zero(&tsk->ptrace_bp_refcnt))
1063 return 0;
1065 return -1;
1068 void ptrace_put_breakpoints(struct task_struct *tsk)
1070 if (atomic_dec_and_test(&tsk->ptrace_bp_refcnt))
1071 flush_ptrace_hw_breakpoint(tsk);
1073 #endif /* CONFIG_HAVE_HW_BREAKPOINT */