mfd: Support 88pm8606 in 860x driver
[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/smp_lock.h>
18 #include <linux/ptrace.h>
19 #include <linux/security.h>
20 #include <linux/signal.h>
21 #include <linux/audit.h>
22 #include <linux/pid_namespace.h>
23 #include <linux/syscalls.h>
24 #include <linux/uaccess.h>
25 #include <linux/regset.h>
26
27
28 /*
29  * ptrace a task: make the debugger its new parent and
30  * move it to the ptrace list.
31  *
32  * Must be called with the tasklist lock write-held.
33  */
34 void __ptrace_link(struct task_struct *child, struct task_struct *new_parent)
35 {
36         BUG_ON(!list_empty(&child->ptrace_entry));
37         list_add(&child->ptrace_entry, &new_parent->ptraced);
38         child->parent = new_parent;
39 }
40
41 /*
42  * Turn a tracing stop into a normal stop now, since with no tracer there
43  * would be no way to wake it up with SIGCONT or SIGKILL.  If there was a
44  * signal sent that would resume the child, but didn't because it was in
45  * TASK_TRACED, resume it now.
46  * Requires that irqs be disabled.
47  */
48 static void ptrace_untrace(struct task_struct *child)
49 {
50         spin_lock(&child->sighand->siglock);
51         if (task_is_traced(child)) {
52                 /*
53                  * If the group stop is completed or in progress,
54                  * this thread was already counted as stopped.
55                  */
56                 if (child->signal->flags & SIGNAL_STOP_STOPPED ||
57                     child->signal->group_stop_count)
58                         __set_task_state(child, TASK_STOPPED);
59                 else
60                         signal_wake_up(child, 1);
61         }
62         spin_unlock(&child->sighand->siglock);
63 }
64
65 /*
66  * unptrace a task: move it back to its original parent and
67  * remove it from the ptrace list.
68  *
69  * Must be called with the tasklist lock write-held.
70  */
71 void __ptrace_unlink(struct task_struct *child)
72 {
73         BUG_ON(!child->ptrace);
74
75         child->ptrace = 0;
76         child->parent = child->real_parent;
77         list_del_init(&child->ptrace_entry);
78
79         arch_ptrace_untrace(child);
80         if (task_is_traced(child))
81                 ptrace_untrace(child);
82 }
83
84 /*
85  * Check that we have indeed attached to the thing..
86  */
87 int ptrace_check_attach(struct task_struct *child, int kill)
88 {
89         int ret = -ESRCH;
90
91         /*
92          * We take the read lock around doing both checks to close a
93          * possible race where someone else was tracing our child and
94          * detached between these two checks.  After this locked check,
95          * we are sure that this is our traced child and that can only
96          * be changed by us so it's not changing right after this.
97          */
98         read_lock(&tasklist_lock);
99         if ((child->ptrace & PT_PTRACED) && child->parent == current) {
100                 ret = 0;
101                 /*
102                  * child->sighand can't be NULL, release_task()
103                  * does ptrace_unlink() before __exit_signal().
104                  */
105                 spin_lock_irq(&child->sighand->siglock);
106                 if (task_is_stopped(child))
107                         child->state = TASK_TRACED;
108                 else if (!task_is_traced(child) && !kill)
109                         ret = -ESRCH;
110                 spin_unlock_irq(&child->sighand->siglock);
111         }
112         read_unlock(&tasklist_lock);
113
114         if (!ret && !kill)
115                 ret = wait_task_inactive(child, TASK_TRACED) ? 0 : -ESRCH;
116
117         /* All systems go.. */
118         return ret;
119 }
120
121 int __ptrace_may_access(struct task_struct *task, unsigned int mode)
122 {
123         const struct cred *cred = current_cred(), *tcred;
124
125         /* May we inspect the given task?
126          * This check is used both for attaching with ptrace
127          * and for allowing access to sensitive information in /proc.
128          *
129          * ptrace_attach denies several cases that /proc allows
130          * because setting up the necessary parent/child relationship
131          * or halting the specified task is impossible.
132          */
133         int dumpable = 0;
134         /* Don't let security modules deny introspection */
135         if (task == current)
136                 return 0;
137         rcu_read_lock();
138         tcred = __task_cred(task);
139         if ((cred->uid != tcred->euid ||
140              cred->uid != tcred->suid ||
141              cred->uid != tcred->uid  ||
142              cred->gid != tcred->egid ||
143              cred->gid != tcred->sgid ||
144              cred->gid != tcred->gid) &&
145             !capable(CAP_SYS_PTRACE)) {
146                 rcu_read_unlock();
147                 return -EPERM;
148         }
149         rcu_read_unlock();
150         smp_rmb();
151         if (task->mm)
152                 dumpable = get_dumpable(task->mm);
153         if (!dumpable && !capable(CAP_SYS_PTRACE))
154                 return -EPERM;
155
156         return security_ptrace_access_check(task, mode);
157 }
158
159 bool ptrace_may_access(struct task_struct *task, unsigned int mode)
160 {
161         int err;
162         task_lock(task);
163         err = __ptrace_may_access(task, mode);
164         task_unlock(task);
165         return !err;
166 }
167
168 int ptrace_attach(struct task_struct *task)
169 {
170         int retval;
171
172         audit_ptrace(task);
173
174         retval = -EPERM;
175         if (unlikely(task->flags & PF_KTHREAD))
176                 goto out;
177         if (same_thread_group(task, current))
178                 goto out;
179
180         /*
181          * Protect exec's credential calculations against our interference;
182          * interference; SUID, SGID and LSM creds get determined differently
183          * under ptrace.
184          */
185         retval = -ERESTARTNOINTR;
186         if (mutex_lock_interruptible(&task->cred_guard_mutex))
187                 goto out;
188
189         task_lock(task);
190         retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH);
191         task_unlock(task);
192         if (retval)
193                 goto unlock_creds;
194
195         write_lock_irq(&tasklist_lock);
196         retval = -EPERM;
197         if (unlikely(task->exit_state))
198                 goto unlock_tasklist;
199         if (task->ptrace)
200                 goto unlock_tasklist;
201
202         task->ptrace = PT_PTRACED;
203         if (capable(CAP_SYS_PTRACE))
204                 task->ptrace |= PT_PTRACE_CAP;
205
206         __ptrace_link(task, current);
207         send_sig_info(SIGSTOP, SEND_SIG_FORCED, task);
208
209         retval = 0;
210 unlock_tasklist:
211         write_unlock_irq(&tasklist_lock);
212 unlock_creds:
213         mutex_unlock(&task->cred_guard_mutex);
214 out:
215         return retval;
216 }
217
218 /**
219  * ptrace_traceme  --  helper for PTRACE_TRACEME
220  *
221  * Performs checks and sets PT_PTRACED.
222  * Should be used by all ptrace implementations for PTRACE_TRACEME.
223  */
224 int ptrace_traceme(void)
225 {
226         int ret = -EPERM;
227
228         write_lock_irq(&tasklist_lock);
229         /* Are we already being traced? */
230         if (!current->ptrace) {
231                 ret = security_ptrace_traceme(current->parent);
232                 /*
233                  * Check PF_EXITING to ensure ->real_parent has not passed
234                  * exit_ptrace(). Otherwise we don't report the error but
235                  * pretend ->real_parent untraces us right after return.
236                  */
237                 if (!ret && !(current->real_parent->flags & PF_EXITING)) {
238                         current->ptrace = PT_PTRACED;
239                         __ptrace_link(current, current->real_parent);
240                 }
241         }
242         write_unlock_irq(&tasklist_lock);
243
244         return ret;
245 }
246
247 /*
248  * Called with irqs disabled, returns true if childs should reap themselves.
249  */
250 static int ignoring_children(struct sighand_struct *sigh)
251 {
252         int ret;
253         spin_lock(&sigh->siglock);
254         ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) ||
255               (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT);
256         spin_unlock(&sigh->siglock);
257         return ret;
258 }
259
260 /*
261  * Called with tasklist_lock held for writing.
262  * Unlink a traced task, and clean it up if it was a traced zombie.
263  * Return true if it needs to be reaped with release_task().
264  * (We can't call release_task() here because we already hold tasklist_lock.)
265  *
266  * If it's a zombie, our attachedness prevented normal parent notification
267  * or self-reaping.  Do notification now if it would have happened earlier.
268  * If it should reap itself, return true.
269  *
270  * If it's our own child, there is no notification to do. But if our normal
271  * children self-reap, then this child was prevented by ptrace and we must
272  * reap it now, in that case we must also wake up sub-threads sleeping in
273  * do_wait().
274  */
275 static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p)
276 {
277         __ptrace_unlink(p);
278
279         if (p->exit_state == EXIT_ZOMBIE) {
280                 if (!task_detached(p) && thread_group_empty(p)) {
281                         if (!same_thread_group(p->real_parent, tracer))
282                                 do_notify_parent(p, p->exit_signal);
283                         else if (ignoring_children(tracer->sighand)) {
284                                 __wake_up_parent(p, tracer);
285                                 p->exit_signal = -1;
286                         }
287                 }
288                 if (task_detached(p)) {
289                         /* Mark it as in the process of being reaped. */
290                         p->exit_state = EXIT_DEAD;
291                         return true;
292                 }
293         }
294
295         return false;
296 }
297
298 int ptrace_detach(struct task_struct *child, unsigned int data)
299 {
300         bool dead = false;
301
302         if (!valid_signal(data))
303                 return -EIO;
304
305         /* Architecture-specific hardware disable .. */
306         ptrace_disable(child);
307         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
308
309         write_lock_irq(&tasklist_lock);
310         /*
311          * This child can be already killed. Make sure de_thread() or
312          * our sub-thread doing do_wait() didn't do release_task() yet.
313          */
314         if (child->ptrace) {
315                 child->exit_code = data;
316                 dead = __ptrace_detach(current, child);
317                 if (!child->exit_state)
318                         wake_up_process(child);
319         }
320         write_unlock_irq(&tasklist_lock);
321
322         if (unlikely(dead))
323                 release_task(child);
324
325         return 0;
326 }
327
328 /*
329  * Detach all tasks we were using ptrace on.
330  */
331 void exit_ptrace(struct task_struct *tracer)
332 {
333         struct task_struct *p, *n;
334         LIST_HEAD(ptrace_dead);
335
336         write_lock_irq(&tasklist_lock);
337         list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) {
338                 if (__ptrace_detach(tracer, p))
339                         list_add(&p->ptrace_entry, &ptrace_dead);
340         }
341         write_unlock_irq(&tasklist_lock);
342
343         BUG_ON(!list_empty(&tracer->ptraced));
344
345         list_for_each_entry_safe(p, n, &ptrace_dead, ptrace_entry) {
346                 list_del_init(&p->ptrace_entry);
347                 release_task(p);
348         }
349 }
350
351 int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len)
352 {
353         int copied = 0;
354
355         while (len > 0) {
356                 char buf[128];
357                 int this_len, retval;
358
359                 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
360                 retval = access_process_vm(tsk, src, buf, this_len, 0);
361                 if (!retval) {
362                         if (copied)
363                                 break;
364                         return -EIO;
365                 }
366                 if (copy_to_user(dst, buf, retval))
367                         return -EFAULT;
368                 copied += retval;
369                 src += retval;
370                 dst += retval;
371                 len -= retval;
372         }
373         return copied;
374 }
375
376 int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len)
377 {
378         int copied = 0;
379
380         while (len > 0) {
381                 char buf[128];
382                 int this_len, retval;
383
384                 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
385                 if (copy_from_user(buf, src, this_len))
386                         return -EFAULT;
387                 retval = access_process_vm(tsk, dst, buf, this_len, 1);
388                 if (!retval) {
389                         if (copied)
390                                 break;
391                         return -EIO;
392                 }
393                 copied += retval;
394                 src += retval;
395                 dst += retval;
396                 len -= retval;
397         }
398         return copied;
399 }
400
401 static int ptrace_setoptions(struct task_struct *child, long data)
402 {
403         child->ptrace &= ~PT_TRACE_MASK;
404
405         if (data & PTRACE_O_TRACESYSGOOD)
406                 child->ptrace |= PT_TRACESYSGOOD;
407
408         if (data & PTRACE_O_TRACEFORK)
409                 child->ptrace |= PT_TRACE_FORK;
410
411         if (data & PTRACE_O_TRACEVFORK)
412                 child->ptrace |= PT_TRACE_VFORK;
413
414         if (data & PTRACE_O_TRACECLONE)
415                 child->ptrace |= PT_TRACE_CLONE;
416
417         if (data & PTRACE_O_TRACEEXEC)
418                 child->ptrace |= PT_TRACE_EXEC;
419
420         if (data & PTRACE_O_TRACEVFORKDONE)
421                 child->ptrace |= PT_TRACE_VFORK_DONE;
422
423         if (data & PTRACE_O_TRACEEXIT)
424                 child->ptrace |= PT_TRACE_EXIT;
425
426         return (data & ~PTRACE_O_MASK) ? -EINVAL : 0;
427 }
428
429 static int ptrace_getsiginfo(struct task_struct *child, siginfo_t *info)
430 {
431         unsigned long flags;
432         int error = -ESRCH;
433
434         if (lock_task_sighand(child, &flags)) {
435                 error = -EINVAL;
436                 if (likely(child->last_siginfo != NULL)) {
437                         *info = *child->last_siginfo;
438                         error = 0;
439                 }
440                 unlock_task_sighand(child, &flags);
441         }
442         return error;
443 }
444
445 static int ptrace_setsiginfo(struct task_struct *child, const siginfo_t *info)
446 {
447         unsigned long flags;
448         int error = -ESRCH;
449
450         if (lock_task_sighand(child, &flags)) {
451                 error = -EINVAL;
452                 if (likely(child->last_siginfo != NULL)) {
453                         *child->last_siginfo = *info;
454                         error = 0;
455                 }
456                 unlock_task_sighand(child, &flags);
457         }
458         return error;
459 }
460
461
462 #ifdef PTRACE_SINGLESTEP
463 #define is_singlestep(request)          ((request) == PTRACE_SINGLESTEP)
464 #else
465 #define is_singlestep(request)          0
466 #endif
467
468 #ifdef PTRACE_SINGLEBLOCK
469 #define is_singleblock(request)         ((request) == PTRACE_SINGLEBLOCK)
470 #else
471 #define is_singleblock(request)         0
472 #endif
473
474 #ifdef PTRACE_SYSEMU
475 #define is_sysemu_singlestep(request)   ((request) == PTRACE_SYSEMU_SINGLESTEP)
476 #else
477 #define is_sysemu_singlestep(request)   0
478 #endif
479
480 static int ptrace_resume(struct task_struct *child, long request, long data)
481 {
482         if (!valid_signal(data))
483                 return -EIO;
484
485         if (request == PTRACE_SYSCALL)
486                 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
487         else
488                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
489
490 #ifdef TIF_SYSCALL_EMU
491         if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP)
492                 set_tsk_thread_flag(child, TIF_SYSCALL_EMU);
493         else
494                 clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
495 #endif
496
497         if (is_singleblock(request)) {
498                 if (unlikely(!arch_has_block_step()))
499                         return -EIO;
500                 user_enable_block_step(child);
501         } else if (is_singlestep(request) || is_sysemu_singlestep(request)) {
502                 if (unlikely(!arch_has_single_step()))
503                         return -EIO;
504                 user_enable_single_step(child);
505         } else {
506                 user_disable_single_step(child);
507         }
508
509         child->exit_code = data;
510         wake_up_process(child);
511
512         return 0;
513 }
514
515 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
516
517 static const struct user_regset *
518 find_regset(const struct user_regset_view *view, unsigned int type)
519 {
520         const struct user_regset *regset;
521         int n;
522
523         for (n = 0; n < view->n; ++n) {
524                 regset = view->regsets + n;
525                 if (regset->core_note_type == type)
526                         return regset;
527         }
528
529         return NULL;
530 }
531
532 static int ptrace_regset(struct task_struct *task, int req, unsigned int type,
533                          struct iovec *kiov)
534 {
535         const struct user_regset_view *view = task_user_regset_view(task);
536         const struct user_regset *regset = find_regset(view, type);
537         int regset_no;
538
539         if (!regset || (kiov->iov_len % regset->size) != 0)
540                 return -EINVAL;
541
542         regset_no = regset - view->regsets;
543         kiov->iov_len = min(kiov->iov_len,
544                             (__kernel_size_t) (regset->n * regset->size));
545
546         if (req == PTRACE_GETREGSET)
547                 return copy_regset_to_user(task, view, regset_no, 0,
548                                            kiov->iov_len, kiov->iov_base);
549         else
550                 return copy_regset_from_user(task, view, regset_no, 0,
551                                              kiov->iov_len, kiov->iov_base);
552 }
553
554 #endif
555
556 int ptrace_request(struct task_struct *child, long request,
557                    long addr, long data)
558 {
559         int ret = -EIO;
560         siginfo_t siginfo;
561
562         switch (request) {
563         case PTRACE_PEEKTEXT:
564         case PTRACE_PEEKDATA:
565                 return generic_ptrace_peekdata(child, addr, data);
566         case PTRACE_POKETEXT:
567         case PTRACE_POKEDATA:
568                 return generic_ptrace_pokedata(child, addr, data);
569
570 #ifdef PTRACE_OLDSETOPTIONS
571         case PTRACE_OLDSETOPTIONS:
572 #endif
573         case PTRACE_SETOPTIONS:
574                 ret = ptrace_setoptions(child, data);
575                 break;
576         case PTRACE_GETEVENTMSG:
577                 ret = put_user(child->ptrace_message, (unsigned long __user *) data);
578                 break;
579
580         case PTRACE_GETSIGINFO:
581                 ret = ptrace_getsiginfo(child, &siginfo);
582                 if (!ret)
583                         ret = copy_siginfo_to_user((siginfo_t __user *) data,
584                                                    &siginfo);
585                 break;
586
587         case PTRACE_SETSIGINFO:
588                 if (copy_from_user(&siginfo, (siginfo_t __user *) data,
589                                    sizeof siginfo))
590                         ret = -EFAULT;
591                 else
592                         ret = ptrace_setsiginfo(child, &siginfo);
593                 break;
594
595         case PTRACE_DETACH:      /* detach a process that was attached. */
596                 ret = ptrace_detach(child, data);
597                 break;
598
599 #ifdef PTRACE_SINGLESTEP
600         case PTRACE_SINGLESTEP:
601 #endif
602 #ifdef PTRACE_SINGLEBLOCK
603         case PTRACE_SINGLEBLOCK:
604 #endif
605 #ifdef PTRACE_SYSEMU
606         case PTRACE_SYSEMU:
607         case PTRACE_SYSEMU_SINGLESTEP:
608 #endif
609         case PTRACE_SYSCALL:
610         case PTRACE_CONT:
611                 return ptrace_resume(child, request, data);
612
613         case PTRACE_KILL:
614                 if (child->exit_state)  /* already dead */
615                         return 0;
616                 return ptrace_resume(child, request, SIGKILL);
617
618 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
619         case PTRACE_GETREGSET:
620         case PTRACE_SETREGSET:
621         {
622                 struct iovec kiov;
623                 struct iovec __user *uiov = (struct iovec __user *) data;
624
625                 if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov)))
626                         return -EFAULT;
627
628                 if (__get_user(kiov.iov_base, &uiov->iov_base) ||
629                     __get_user(kiov.iov_len, &uiov->iov_len))
630                         return -EFAULT;
631
632                 ret = ptrace_regset(child, request, addr, &kiov);
633                 if (!ret)
634                         ret = __put_user(kiov.iov_len, &uiov->iov_len);
635                 break;
636         }
637 #endif
638         default:
639                 break;
640         }
641
642         return ret;
643 }
644
645 static struct task_struct *ptrace_get_task_struct(pid_t pid)
646 {
647         struct task_struct *child;
648
649         rcu_read_lock();
650         child = find_task_by_vpid(pid);
651         if (child)
652                 get_task_struct(child);
653         rcu_read_unlock();
654
655         if (!child)
656                 return ERR_PTR(-ESRCH);
657         return child;
658 }
659
660 #ifndef arch_ptrace_attach
661 #define arch_ptrace_attach(child)       do { } while (0)
662 #endif
663
664 SYSCALL_DEFINE4(ptrace, long, request, long, pid, long, addr, long, data)
665 {
666         struct task_struct *child;
667         long ret;
668
669         /*
670          * This lock_kernel fixes a subtle race with suid exec
671          */
672         lock_kernel();
673         if (request == PTRACE_TRACEME) {
674                 ret = ptrace_traceme();
675                 if (!ret)
676                         arch_ptrace_attach(current);
677                 goto out;
678         }
679
680         child = ptrace_get_task_struct(pid);
681         if (IS_ERR(child)) {
682                 ret = PTR_ERR(child);
683                 goto out;
684         }
685
686         if (request == PTRACE_ATTACH) {
687                 ret = ptrace_attach(child);
688                 /*
689                  * Some architectures need to do book-keeping after
690                  * a ptrace attach.
691                  */
692                 if (!ret)
693                         arch_ptrace_attach(child);
694                 goto out_put_task_struct;
695         }
696
697         ret = ptrace_check_attach(child, request == PTRACE_KILL);
698         if (ret < 0)
699                 goto out_put_task_struct;
700
701         ret = arch_ptrace(child, request, addr, data);
702
703  out_put_task_struct:
704         put_task_struct(child);
705  out:
706         unlock_kernel();
707         return ret;
708 }
709
710 int generic_ptrace_peekdata(struct task_struct *tsk, long addr, long data)
711 {
712         unsigned long tmp;
713         int copied;
714
715         copied = access_process_vm(tsk, addr, &tmp, sizeof(tmp), 0);
716         if (copied != sizeof(tmp))
717                 return -EIO;
718         return put_user(tmp, (unsigned long __user *)data);
719 }
720
721 int generic_ptrace_pokedata(struct task_struct *tsk, long addr, long data)
722 {
723         int copied;
724
725         copied = access_process_vm(tsk, addr, &data, sizeof(data), 1);
726         return (copied == sizeof(data)) ? 0 : -EIO;
727 }
728
729 #if defined CONFIG_COMPAT
730 #include <linux/compat.h>
731
732 int compat_ptrace_request(struct task_struct *child, compat_long_t request,
733                           compat_ulong_t addr, compat_ulong_t data)
734 {
735         compat_ulong_t __user *datap = compat_ptr(data);
736         compat_ulong_t word;
737         siginfo_t siginfo;
738         int ret;
739
740         switch (request) {
741         case PTRACE_PEEKTEXT:
742         case PTRACE_PEEKDATA:
743                 ret = access_process_vm(child, addr, &word, sizeof(word), 0);
744                 if (ret != sizeof(word))
745                         ret = -EIO;
746                 else
747                         ret = put_user(word, datap);
748                 break;
749
750         case PTRACE_POKETEXT:
751         case PTRACE_POKEDATA:
752                 ret = access_process_vm(child, addr, &data, sizeof(data), 1);
753                 ret = (ret != sizeof(data) ? -EIO : 0);
754                 break;
755
756         case PTRACE_GETEVENTMSG:
757                 ret = put_user((compat_ulong_t) child->ptrace_message, datap);
758                 break;
759
760         case PTRACE_GETSIGINFO:
761                 ret = ptrace_getsiginfo(child, &siginfo);
762                 if (!ret)
763                         ret = copy_siginfo_to_user32(
764                                 (struct compat_siginfo __user *) datap,
765                                 &siginfo);
766                 break;
767
768         case PTRACE_SETSIGINFO:
769                 memset(&siginfo, 0, sizeof siginfo);
770                 if (copy_siginfo_from_user32(
771                             &siginfo, (struct compat_siginfo __user *) datap))
772                         ret = -EFAULT;
773                 else
774                         ret = ptrace_setsiginfo(child, &siginfo);
775                 break;
776 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
777         case PTRACE_GETREGSET:
778         case PTRACE_SETREGSET:
779         {
780                 struct iovec kiov;
781                 struct compat_iovec __user *uiov =
782                         (struct compat_iovec __user *) datap;
783                 compat_uptr_t ptr;
784                 compat_size_t len;
785
786                 if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov)))
787                         return -EFAULT;
788
789                 if (__get_user(ptr, &uiov->iov_base) ||
790                     __get_user(len, &uiov->iov_len))
791                         return -EFAULT;
792
793                 kiov.iov_base = compat_ptr(ptr);
794                 kiov.iov_len = len;
795
796                 ret = ptrace_regset(child, request, addr, &kiov);
797                 if (!ret)
798                         ret = __put_user(kiov.iov_len, &uiov->iov_len);
799                 break;
800         }
801 #endif
802
803         default:
804                 ret = ptrace_request(child, request, addr, data);
805         }
806
807         return ret;
808 }
809
810 asmlinkage long compat_sys_ptrace(compat_long_t request, compat_long_t pid,
811                                   compat_long_t addr, compat_long_t data)
812 {
813         struct task_struct *child;
814         long ret;
815
816         /*
817          * This lock_kernel fixes a subtle race with suid exec
818          */
819         lock_kernel();
820         if (request == PTRACE_TRACEME) {
821                 ret = ptrace_traceme();
822                 goto out;
823         }
824
825         child = ptrace_get_task_struct(pid);
826         if (IS_ERR(child)) {
827                 ret = PTR_ERR(child);
828                 goto out;
829         }
830
831         if (request == PTRACE_ATTACH) {
832                 ret = ptrace_attach(child);
833                 /*
834                  * Some architectures need to do book-keeping after
835                  * a ptrace attach.
836                  */
837                 if (!ret)
838                         arch_ptrace_attach(child);
839                 goto out_put_task_struct;
840         }
841
842         ret = ptrace_check_attach(child, request == PTRACE_KILL);
843         if (!ret)
844                 ret = compat_arch_ptrace(child, request, addr, data);
845
846  out_put_task_struct:
847         put_task_struct(child);
848  out:
849         unlock_kernel();
850         return ret;
851 }
852 #endif  /* CONFIG_COMPAT */