2f0f50b450a336351b7d8ca547dab63b648a264e
[linux-2.6.git] / kernel / ptrace.c
1 /*
2  * linux/kernel/ptrace.c
3  *
4  * (C) Copyright 1999 Linus Torvalds
5  *
6  * Common interfaces for "ptrace()" which we do not want
7  * to continually duplicate across every architecture.
8  */
9
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>
25
26
27 /*
28  * ptrace a task: make the debugger its new parent and
29  * move it to the ptrace list.
30  *
31  * Must be called with the tasklist lock write-held.
32  */
33 void __ptrace_link(struct task_struct *child, struct task_struct *new_parent)
34 {
35         BUG_ON(!list_empty(&child->ptrace_entry));
36         list_add(&child->ptrace_entry, &new_parent->ptraced);
37         child->parent = new_parent;
38 }
39
40 /*
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.
46  */
47 static void ptrace_untrace(struct task_struct *child)
48 {
49         spin_lock(&child->sighand->siglock);
50         if (task_is_traced(child)) {
51                 /*
52                  * If the group stop is completed or in progress,
53                  * this thread was already counted as stopped.
54                  */
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);
60         }
61         spin_unlock(&child->sighand->siglock);
62 }
63
64 /*
65  * unptrace a task: move it back to its original parent and
66  * remove it from the ptrace list.
67  *
68  * Must be called with the tasklist lock write-held.
69  */
70 void __ptrace_unlink(struct task_struct *child)
71 {
72         BUG_ON(!child->ptrace);
73
74         child->ptrace = 0;
75         child->parent = child->real_parent;
76         list_del_init(&child->ptrace_entry);
77
78         arch_ptrace_untrace(child);
79         if (task_is_traced(child))
80                 ptrace_untrace(child);
81 }
82
83 /*
84  * Check that we have indeed attached to the thing..
85  */
86 int ptrace_check_attach(struct task_struct *child, int kill)
87 {
88         int ret = -ESRCH;
89
90         /*
91          * We take the read lock around doing both checks to close a
92          * possible race where someone else was tracing our child and
93          * detached between these two checks.  After this locked check,
94          * we are sure that this is our traced child and that can only
95          * be changed by us so it's not changing right after this.
96          */
97         read_lock(&tasklist_lock);
98         if ((child->ptrace & PT_PTRACED) && child->parent == current) {
99                 ret = 0;
100                 /*
101                  * child->sighand can't be NULL, release_task()
102                  * does ptrace_unlink() before __exit_signal().
103                  */
104                 spin_lock_irq(&child->sighand->siglock);
105                 if (task_is_stopped(child))
106                         child->state = TASK_TRACED;
107                 else if (!task_is_traced(child) && !kill)
108                         ret = -ESRCH;
109                 spin_unlock_irq(&child->sighand->siglock);
110         }
111         read_unlock(&tasklist_lock);
112
113         if (!ret && !kill)
114                 ret = wait_task_inactive(child, TASK_TRACED) ? 0 : -ESRCH;
115
116         /* All systems go.. */
117         return ret;
118 }
119
120 int __ptrace_may_access(struct task_struct *task, unsigned int mode)
121 {
122         const struct cred *cred = current_cred(), *tcred;
123
124         /* May we inspect the given task?
125          * This check is used both for attaching with ptrace
126          * and for allowing access to sensitive information in /proc.
127          *
128          * ptrace_attach denies several cases that /proc allows
129          * because setting up the necessary parent/child relationship
130          * or halting the specified task is impossible.
131          */
132         int dumpable = 0;
133         /* Don't let security modules deny introspection */
134         if (task == current)
135                 return 0;
136         rcu_read_lock();
137         tcred = __task_cred(task);
138         if ((cred->uid != tcred->euid ||
139              cred->uid != tcred->suid ||
140              cred->uid != tcred->uid  ||
141              cred->gid != tcred->egid ||
142              cred->gid != tcred->sgid ||
143              cred->gid != tcred->gid) &&
144             !capable(CAP_SYS_PTRACE)) {
145                 rcu_read_unlock();
146                 return -EPERM;
147         }
148         rcu_read_unlock();
149         smp_rmb();
150         if (task->mm)
151                 dumpable = get_dumpable(task->mm);
152         if (!dumpable && !capable(CAP_SYS_PTRACE))
153                 return -EPERM;
154
155         return security_ptrace_access_check(task, mode);
156 }
157
158 bool ptrace_may_access(struct task_struct *task, unsigned int mode)
159 {
160         int err;
161         task_lock(task);
162         err = __ptrace_may_access(task, mode);
163         task_unlock(task);
164         return !err;
165 }
166
167 int ptrace_attach(struct task_struct *task)
168 {
169         int retval;
170
171         audit_ptrace(task);
172
173         retval = -EPERM;
174         if (unlikely(task->flags & PF_KTHREAD))
175                 goto out;
176         if (same_thread_group(task, current))
177                 goto out;
178
179         /*
180          * Protect exec's credential calculations against our interference;
181          * interference; SUID, SGID and LSM creds get determined differently
182          * under ptrace.
183          */
184         retval = -ERESTARTNOINTR;
185         if (mutex_lock_interruptible(&task->cred_guard_mutex))
186                 goto out;
187
188         task_lock(task);
189         retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH);
190         task_unlock(task);
191         if (retval)
192                 goto unlock_creds;
193
194         write_lock_irq(&tasklist_lock);
195         retval = -EPERM;
196         if (unlikely(task->exit_state))
197                 goto unlock_tasklist;
198         if (task->ptrace)
199                 goto unlock_tasklist;
200
201         task->ptrace = PT_PTRACED;
202         if (capable(CAP_SYS_PTRACE))
203                 task->ptrace |= PT_PTRACE_CAP;
204
205         __ptrace_link(task, current);
206         send_sig_info(SIGSTOP, SEND_SIG_FORCED, task);
207
208         retval = 0;
209 unlock_tasklist:
210         write_unlock_irq(&tasklist_lock);
211 unlock_creds:
212         mutex_unlock(&task->cred_guard_mutex);
213 out:
214         return retval;
215 }
216
217 /**
218  * ptrace_traceme  --  helper for PTRACE_TRACEME
219  *
220  * Performs checks and sets PT_PTRACED.
221  * Should be used by all ptrace implementations for PTRACE_TRACEME.
222  */
223 int ptrace_traceme(void)
224 {
225         int ret = -EPERM;
226
227         write_lock_irq(&tasklist_lock);
228         /* Are we already being traced? */
229         if (!current->ptrace) {
230                 ret = security_ptrace_traceme(current->parent);
231                 /*
232                  * Check PF_EXITING to ensure ->real_parent has not passed
233                  * exit_ptrace(). Otherwise we don't report the error but
234                  * pretend ->real_parent untraces us right after return.
235                  */
236                 if (!ret && !(current->real_parent->flags & PF_EXITING)) {
237                         current->ptrace = PT_PTRACED;
238                         __ptrace_link(current, current->real_parent);
239                 }
240         }
241         write_unlock_irq(&tasklist_lock);
242
243         return ret;
244 }
245
246 /*
247  * Called with irqs disabled, returns true if childs should reap themselves.
248  */
249 static int ignoring_children(struct sighand_struct *sigh)
250 {
251         int ret;
252         spin_lock(&sigh->siglock);
253         ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) ||
254               (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT);
255         spin_unlock(&sigh->siglock);
256         return ret;
257 }
258
259 /*
260  * Called with tasklist_lock held for writing.
261  * Unlink a traced task, and clean it up if it was a traced zombie.
262  * Return true if it needs to be reaped with release_task().
263  * (We can't call release_task() here because we already hold tasklist_lock.)
264  *
265  * If it's a zombie, our attachedness prevented normal parent notification
266  * or self-reaping.  Do notification now if it would have happened earlier.
267  * If it should reap itself, return true.
268  *
269  * If it's our own child, there is no notification to do. But if our normal
270  * children self-reap, then this child was prevented by ptrace and we must
271  * reap it now, in that case we must also wake up sub-threads sleeping in
272  * do_wait().
273  */
274 static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p)
275 {
276         __ptrace_unlink(p);
277
278         if (p->exit_state == EXIT_ZOMBIE) {
279                 if (!task_detached(p) && thread_group_empty(p)) {
280                         if (!same_thread_group(p->real_parent, tracer))
281                                 do_notify_parent(p, p->exit_signal);
282                         else if (ignoring_children(tracer->sighand)) {
283                                 __wake_up_parent(p, tracer);
284                                 p->exit_signal = -1;
285                         }
286                 }
287                 if (task_detached(p)) {
288                         /* Mark it as in the process of being reaped. */
289                         p->exit_state = EXIT_DEAD;
290                         return true;
291                 }
292         }
293
294         return false;
295 }
296
297 int ptrace_detach(struct task_struct *child, unsigned int data)
298 {
299         bool dead = false;
300
301         if (!valid_signal(data))
302                 return -EIO;
303
304         /* Architecture-specific hardware disable .. */
305         ptrace_disable(child);
306         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
307
308         write_lock_irq(&tasklist_lock);
309         /*
310          * This child can be already killed. Make sure de_thread() or
311          * our sub-thread doing do_wait() didn't do release_task() yet.
312          */
313         if (child->ptrace) {
314                 child->exit_code = data;
315                 dead = __ptrace_detach(current, child);
316                 if (!child->exit_state)
317                         wake_up_process(child);
318         }
319         write_unlock_irq(&tasklist_lock);
320
321         if (unlikely(dead))
322                 release_task(child);
323
324         return 0;
325 }
326
327 /*
328  * Detach all tasks we were using ptrace on.
329  */
330 void exit_ptrace(struct task_struct *tracer)
331 {
332         struct task_struct *p, *n;
333         LIST_HEAD(ptrace_dead);
334
335         write_lock_irq(&tasklist_lock);
336         list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) {
337                 if (__ptrace_detach(tracer, p))
338                         list_add(&p->ptrace_entry, &ptrace_dead);
339         }
340         write_unlock_irq(&tasklist_lock);
341
342         BUG_ON(!list_empty(&tracer->ptraced));
343
344         list_for_each_entry_safe(p, n, &ptrace_dead, ptrace_entry) {
345                 list_del_init(&p->ptrace_entry);
346                 release_task(p);
347         }
348 }
349
350 int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len)
351 {
352         int copied = 0;
353
354         while (len > 0) {
355                 char buf[128];
356                 int this_len, retval;
357
358                 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
359                 retval = access_process_vm(tsk, src, buf, this_len, 0);
360                 if (!retval) {
361                         if (copied)
362                                 break;
363                         return -EIO;
364                 }
365                 if (copy_to_user(dst, buf, retval))
366                         return -EFAULT;
367                 copied += retval;
368                 src += retval;
369                 dst += retval;
370                 len -= retval;
371         }
372         return copied;
373 }
374
375 int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len)
376 {
377         int copied = 0;
378
379         while (len > 0) {
380                 char buf[128];
381                 int this_len, retval;
382
383                 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
384                 if (copy_from_user(buf, src, this_len))
385                         return -EFAULT;
386                 retval = access_process_vm(tsk, dst, buf, this_len, 1);
387                 if (!retval) {
388                         if (copied)
389                                 break;
390                         return -EIO;
391                 }
392                 copied += retval;
393                 src += retval;
394                 dst += retval;
395                 len -= retval;
396         }
397         return copied;
398 }
399
400 static int ptrace_setoptions(struct task_struct *child, long data)
401 {
402         child->ptrace &= ~PT_TRACE_MASK;
403
404         if (data & PTRACE_O_TRACESYSGOOD)
405                 child->ptrace |= PT_TRACESYSGOOD;
406
407         if (data & PTRACE_O_TRACEFORK)
408                 child->ptrace |= PT_TRACE_FORK;
409
410         if (data & PTRACE_O_TRACEVFORK)
411                 child->ptrace |= PT_TRACE_VFORK;
412
413         if (data & PTRACE_O_TRACECLONE)
414                 child->ptrace |= PT_TRACE_CLONE;
415
416         if (data & PTRACE_O_TRACEEXEC)
417                 child->ptrace |= PT_TRACE_EXEC;
418
419         if (data & PTRACE_O_TRACEVFORKDONE)
420                 child->ptrace |= PT_TRACE_VFORK_DONE;
421
422         if (data & PTRACE_O_TRACEEXIT)
423                 child->ptrace |= PT_TRACE_EXIT;
424
425         return (data & ~PTRACE_O_MASK) ? -EINVAL : 0;
426 }
427
428 static int ptrace_getsiginfo(struct task_struct *child, siginfo_t *info)
429 {
430         unsigned long flags;
431         int error = -ESRCH;
432
433         if (lock_task_sighand(child, &flags)) {
434                 error = -EINVAL;
435                 if (likely(child->last_siginfo != NULL)) {
436                         *info = *child->last_siginfo;
437                         error = 0;
438                 }
439                 unlock_task_sighand(child, &flags);
440         }
441         return error;
442 }
443
444 static int ptrace_setsiginfo(struct task_struct *child, const siginfo_t *info)
445 {
446         unsigned long flags;
447         int error = -ESRCH;
448
449         if (lock_task_sighand(child, &flags)) {
450                 error = -EINVAL;
451                 if (likely(child->last_siginfo != NULL)) {
452                         *child->last_siginfo = *info;
453                         error = 0;
454                 }
455                 unlock_task_sighand(child, &flags);
456         }
457         return error;
458 }
459
460
461 #ifdef PTRACE_SINGLESTEP
462 #define is_singlestep(request)          ((request) == PTRACE_SINGLESTEP)
463 #else
464 #define is_singlestep(request)          0
465 #endif
466
467 #ifdef PTRACE_SINGLEBLOCK
468 #define is_singleblock(request)         ((request) == PTRACE_SINGLEBLOCK)
469 #else
470 #define is_singleblock(request)         0
471 #endif
472
473 #ifdef PTRACE_SYSEMU
474 #define is_sysemu_singlestep(request)   ((request) == PTRACE_SYSEMU_SINGLESTEP)
475 #else
476 #define is_sysemu_singlestep(request)   0
477 #endif
478
479 static int ptrace_resume(struct task_struct *child, long request, long data)
480 {
481         if (!valid_signal(data))
482                 return -EIO;
483
484         if (request == PTRACE_SYSCALL)
485                 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
486         else
487                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
488
489 #ifdef TIF_SYSCALL_EMU
490         if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP)
491                 set_tsk_thread_flag(child, TIF_SYSCALL_EMU);
492         else
493                 clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
494 #endif
495
496         if (is_singleblock(request)) {
497                 if (unlikely(!arch_has_block_step()))
498                         return -EIO;
499                 user_enable_block_step(child);
500         } else if (is_singlestep(request) || is_sysemu_singlestep(request)) {
501                 if (unlikely(!arch_has_single_step()))
502                         return -EIO;
503                 user_enable_single_step(child);
504         } else {
505                 user_disable_single_step(child);
506         }
507
508         child->exit_code = data;
509         wake_up_process(child);
510
511         return 0;
512 }
513
514 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
515
516 static const struct user_regset *
517 find_regset(const struct user_regset_view *view, unsigned int type)
518 {
519         const struct user_regset *regset;
520         int n;
521
522         for (n = 0; n < view->n; ++n) {
523                 regset = view->regsets + n;
524                 if (regset->core_note_type == type)
525                         return regset;
526         }
527
528         return NULL;
529 }
530
531 static int ptrace_regset(struct task_struct *task, int req, unsigned int type,
532                          struct iovec *kiov)
533 {
534         const struct user_regset_view *view = task_user_regset_view(task);
535         const struct user_regset *regset = find_regset(view, type);
536         int regset_no;
537
538         if (!regset || (kiov->iov_len % regset->size) != 0)
539                 return -EINVAL;
540
541         regset_no = regset - view->regsets;
542         kiov->iov_len = min(kiov->iov_len,
543                             (__kernel_size_t) (regset->n * regset->size));
544
545         if (req == PTRACE_GETREGSET)
546                 return copy_regset_to_user(task, view, regset_no, 0,
547                                            kiov->iov_len, kiov->iov_base);
548         else
549                 return copy_regset_from_user(task, view, regset_no, 0,
550                                              kiov->iov_len, kiov->iov_base);
551 }
552
553 #endif
554
555 int ptrace_request(struct task_struct *child, long request,
556                    long addr, long data)
557 {
558         int ret = -EIO;
559         siginfo_t siginfo;
560
561         switch (request) {
562         case PTRACE_PEEKTEXT:
563         case PTRACE_PEEKDATA:
564                 return generic_ptrace_peekdata(child, addr, data);
565         case PTRACE_POKETEXT:
566         case PTRACE_POKEDATA:
567                 return generic_ptrace_pokedata(child, addr, data);
568
569 #ifdef PTRACE_OLDSETOPTIONS
570         case PTRACE_OLDSETOPTIONS:
571 #endif
572         case PTRACE_SETOPTIONS:
573                 ret = ptrace_setoptions(child, data);
574                 break;
575         case PTRACE_GETEVENTMSG:
576                 ret = put_user(child->ptrace_message, (unsigned long __user *) data);
577                 break;
578
579         case PTRACE_GETSIGINFO:
580                 ret = ptrace_getsiginfo(child, &siginfo);
581                 if (!ret)
582                         ret = copy_siginfo_to_user((siginfo_t __user *) data,
583                                                    &siginfo);
584                 break;
585
586         case PTRACE_SETSIGINFO:
587                 if (copy_from_user(&siginfo, (siginfo_t __user *) data,
588                                    sizeof siginfo))
589                         ret = -EFAULT;
590                 else
591                         ret = ptrace_setsiginfo(child, &siginfo);
592                 break;
593
594         case PTRACE_DETACH:      /* detach a process that was attached. */
595                 ret = ptrace_detach(child, data);
596                 break;
597
598 #ifdef PTRACE_SINGLESTEP
599         case PTRACE_SINGLESTEP:
600 #endif
601 #ifdef PTRACE_SINGLEBLOCK
602         case PTRACE_SINGLEBLOCK:
603 #endif
604 #ifdef PTRACE_SYSEMU
605         case PTRACE_SYSEMU:
606         case PTRACE_SYSEMU_SINGLESTEP:
607 #endif
608         case PTRACE_SYSCALL:
609         case PTRACE_CONT:
610                 return ptrace_resume(child, request, data);
611
612         case PTRACE_KILL:
613                 if (child->exit_state)  /* already dead */
614                         return 0;
615                 return ptrace_resume(child, request, SIGKILL);
616
617 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
618         case PTRACE_GETREGSET:
619         case PTRACE_SETREGSET:
620         {
621                 struct iovec kiov;
622                 struct iovec __user *uiov = (struct iovec __user *) data;
623
624                 if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov)))
625                         return -EFAULT;
626
627                 if (__get_user(kiov.iov_base, &uiov->iov_base) ||
628                     __get_user(kiov.iov_len, &uiov->iov_len))
629                         return -EFAULT;
630
631                 ret = ptrace_regset(child, request, addr, &kiov);
632                 if (!ret)
633                         ret = __put_user(kiov.iov_len, &uiov->iov_len);
634                 break;
635         }
636 #endif
637         default:
638                 break;
639         }
640
641         return ret;
642 }
643
644 static struct task_struct *ptrace_get_task_struct(pid_t pid)
645 {
646         struct task_struct *child;
647
648         rcu_read_lock();
649         child = find_task_by_vpid(pid);
650         if (child)
651                 get_task_struct(child);
652         rcu_read_unlock();
653
654         if (!child)
655                 return ERR_PTR(-ESRCH);
656         return child;
657 }
658
659 #ifndef arch_ptrace_attach
660 #define arch_ptrace_attach(child)       do { } while (0)
661 #endif
662
663 SYSCALL_DEFINE4(ptrace, long, request, long, pid, long, addr, long, data)
664 {
665         struct task_struct *child;
666         long ret;
667
668         if (request == PTRACE_TRACEME) {
669                 ret = ptrace_traceme();
670                 if (!ret)
671                         arch_ptrace_attach(current);
672                 goto out;
673         }
674
675         child = ptrace_get_task_struct(pid);
676         if (IS_ERR(child)) {
677                 ret = PTR_ERR(child);
678                 goto out;
679         }
680
681         if (request == PTRACE_ATTACH) {
682                 ret = ptrace_attach(child);
683                 /*
684                  * Some architectures need to do book-keeping after
685                  * a ptrace attach.
686                  */
687                 if (!ret)
688                         arch_ptrace_attach(child);
689                 goto out_put_task_struct;
690         }
691
692         ret = ptrace_check_attach(child, request == PTRACE_KILL);
693         if (ret < 0)
694                 goto out_put_task_struct;
695
696         ret = arch_ptrace(child, request, addr, data);
697
698  out_put_task_struct:
699         put_task_struct(child);
700  out:
701         return ret;
702 }
703
704 int generic_ptrace_peekdata(struct task_struct *tsk, long addr, long data)
705 {
706         unsigned long tmp;
707         int copied;
708
709         copied = access_process_vm(tsk, addr, &tmp, sizeof(tmp), 0);
710         if (copied != sizeof(tmp))
711                 return -EIO;
712         return put_user(tmp, (unsigned long __user *)data);
713 }
714
715 int generic_ptrace_pokedata(struct task_struct *tsk, long addr, long data)
716 {
717         int copied;
718
719         copied = access_process_vm(tsk, addr, &data, sizeof(data), 1);
720         return (copied == sizeof(data)) ? 0 : -EIO;
721 }
722
723 #if defined CONFIG_COMPAT
724 #include <linux/compat.h>
725
726 int compat_ptrace_request(struct task_struct *child, compat_long_t request,
727                           compat_ulong_t addr, compat_ulong_t data)
728 {
729         compat_ulong_t __user *datap = compat_ptr(data);
730         compat_ulong_t word;
731         siginfo_t siginfo;
732         int ret;
733
734         switch (request) {
735         case PTRACE_PEEKTEXT:
736         case PTRACE_PEEKDATA:
737                 ret = access_process_vm(child, addr, &word, sizeof(word), 0);
738                 if (ret != sizeof(word))
739                         ret = -EIO;
740                 else
741                         ret = put_user(word, datap);
742                 break;
743
744         case PTRACE_POKETEXT:
745         case PTRACE_POKEDATA:
746                 ret = access_process_vm(child, addr, &data, sizeof(data), 1);
747                 ret = (ret != sizeof(data) ? -EIO : 0);
748                 break;
749
750         case PTRACE_GETEVENTMSG:
751                 ret = put_user((compat_ulong_t) child->ptrace_message, datap);
752                 break;
753
754         case PTRACE_GETSIGINFO:
755                 ret = ptrace_getsiginfo(child, &siginfo);
756                 if (!ret)
757                         ret = copy_siginfo_to_user32(
758                                 (struct compat_siginfo __user *) datap,
759                                 &siginfo);
760                 break;
761
762         case PTRACE_SETSIGINFO:
763                 memset(&siginfo, 0, sizeof siginfo);
764                 if (copy_siginfo_from_user32(
765                             &siginfo, (struct compat_siginfo __user *) datap))
766                         ret = -EFAULT;
767                 else
768                         ret = ptrace_setsiginfo(child, &siginfo);
769                 break;
770 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
771         case PTRACE_GETREGSET:
772         case PTRACE_SETREGSET:
773         {
774                 struct iovec kiov;
775                 struct compat_iovec __user *uiov =
776                         (struct compat_iovec __user *) datap;
777                 compat_uptr_t ptr;
778                 compat_size_t len;
779
780                 if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov)))
781                         return -EFAULT;
782
783                 if (__get_user(ptr, &uiov->iov_base) ||
784                     __get_user(len, &uiov->iov_len))
785                         return -EFAULT;
786
787                 kiov.iov_base = compat_ptr(ptr);
788                 kiov.iov_len = len;
789
790                 ret = ptrace_regset(child, request, addr, &kiov);
791                 if (!ret)
792                         ret = __put_user(kiov.iov_len, &uiov->iov_len);
793                 break;
794         }
795 #endif
796
797         default:
798                 ret = ptrace_request(child, request, addr, data);
799         }
800
801         return ret;
802 }
803
804 asmlinkage long compat_sys_ptrace(compat_long_t request, compat_long_t pid,
805                                   compat_long_t addr, compat_long_t data)
806 {
807         struct task_struct *child;
808         long ret;
809
810         if (request == PTRACE_TRACEME) {
811                 ret = ptrace_traceme();
812                 goto out;
813         }
814
815         child = ptrace_get_task_struct(pid);
816         if (IS_ERR(child)) {
817                 ret = PTR_ERR(child);
818                 goto out;
819         }
820
821         if (request == PTRACE_ATTACH) {
822                 ret = ptrace_attach(child);
823                 /*
824                  * Some architectures need to do book-keeping after
825                  * a ptrace attach.
826                  */
827                 if (!ret)
828                         arch_ptrace_attach(child);
829                 goto out_put_task_struct;
830         }
831
832         ret = ptrace_check_attach(child, request == PTRACE_KILL);
833         if (!ret)
834                 ret = compat_arch_ptrace(child, request, addr, data);
835
836  out_put_task_struct:
837         put_task_struct(child);
838  out:
839         return ret;
840 }
841 #endif  /* CONFIG_COMPAT */