[GitHub/mt8127/android_kernel_alcatel_ttab.git] / kernel / ptrace.c

/*
 * linux/kernel/ptrace.c
 *
 * (C) Copyright 1999 Linus Torvalds
 *
 * Common interfaces for "ptrace()" which we do not want
 * to continually duplicate across every architecture.
 */

#include <linux/module.h>
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/mm.h>
#include <linux/highmem.h>
#include <linux/pagemap.h>
#include <linux/smp_lock.h>
#include <linux/ptrace.h>
#include <linux/security.h>
#include <linux/signal.h>

#include <asm/pgtable.h>
#include <asm/uaccess.h>

/*
 * ptrace a task: make the debugger its new parent and
 * move it to the ptrace list.
 *
 * Must be called with the tasklist lock write-held.
 */
void __ptrace_link(task_t *child, task_t *new_parent)
{
	if (!list_empty(&child->ptrace_list))
		BUG();
	if (child->parent == new_parent)
		return;
	list_add(&child->ptrace_list, &child->parent->ptrace_children);
	REMOVE_LINKS(child);
	child->parent = new_parent;
	SET_LINKS(child);
}
 
/*
 * Turn a tracing stop into a normal stop now, since with no tracer there
 * would be no way to wake it up with SIGCONT or SIGKILL.  If there was a
 * signal sent that would resume the child, but didn't because it was in
 * TASK_TRACED, resume it now.
 * Requires that irqs be disabled.
 */
void ptrace_untrace(task_t *child)
{
	spin_lock(&child->sighand->siglock);
	if (child->state == TASK_TRACED) {
		if (child->signal->flags & SIGNAL_STOP_STOPPED) {
			child->state = TASK_STOPPED;
		} else {
			signal_wake_up(child, 1);
		}
	}
	if (child->signal->flags & SIGNAL_GROUP_EXIT) {
		sigaddset(&child->pending.signal, SIGKILL);
		signal_wake_up(child, 1);
	}
	spin_unlock(&child->sighand->siglock);
}

/*
 * unptrace a task: move it back to its original parent and
 * remove it from the ptrace list.
 *
 * Must be called with the tasklist lock write-held.
 */
void __ptrace_unlink(task_t *child)
{
	if (!child->ptrace)
		BUG();
	child->ptrace = 0;
	if (!list_empty(&child->ptrace_list)) {
		list_del_init(&child->ptrace_list);
		REMOVE_LINKS(child);
		child->parent = child->real_parent;
		SET_LINKS(child);
	}

	ptrace_untrace(child);
}

/*
 * Check that we have indeed attached to the thing..
 */
int ptrace_check_attach(struct task_struct *child, int kill)
{
	int ret = -ESRCH;

	/*
	 * We take the read lock around doing both checks to close a
	 * possible race where someone else was tracing our child and
	 * detached between these two checks.  After this locked check,
	 * we are sure that this is our traced child and that can only
	 * be changed by us so it's not changing right after this.
	 */
	read_lock(&tasklist_lock);
	if ((child->ptrace & PT_PTRACED) && child->parent == current &&
	    (!(child->ptrace & PT_ATTACHED) || child->real_parent != current)
	    && child->signal != NULL) {
		ret = 0;
		spin_lock_irq(&child->sighand->siglock);
		if (child->state == TASK_STOPPED) {
			child->state = TASK_TRACED;
		} else if (child->state != TASK_TRACED && !kill) {
			ret = -ESRCH;
		}
		spin_unlock_irq(&child->sighand->siglock);
	}
	read_unlock(&tasklist_lock);

	if (!ret && !kill) {
		wait_task_inactive(child);
	}

	/* All systems go.. */
	return ret;
}

static int may_attach(struct task_struct *task)
{
	if (!task->mm)
		return -EPERM;
	if (((current->uid != task->euid) ||
	     (current->uid != task->suid) ||
	     (current->uid != task->uid) ||
	     (current->gid != task->egid) ||
	     (current->gid != task->sgid) ||
	     (current->gid != task->gid)) && !capable(CAP_SYS_PTRACE))
		return -EPERM;
	smp_rmb();
	if (!task->mm->dumpable && !capable(CAP_SYS_PTRACE))
		return -EPERM;

	return security_ptrace(current, task);
}

int ptrace_may_attach(struct task_struct *task)
{
	int err;
	task_lock(task);
	err = may_attach(task);
	task_unlock(task);
	return !err;
}

int ptrace_attach(struct task_struct *task)
{
	int retval;
	task_lock(task);
	retval = -EPERM;
	if (task->pid <= 1)
		goto bad;
	if (task->tgid == current->tgid)
		goto bad;
	/* the same process cannot be attached many times */
	if (task->ptrace & PT_PTRACED)
		goto bad;
	retval = may_attach(task);
	if (retval)
		goto bad;

	/* Go */
	task->ptrace |= PT_PTRACED | ((task->real_parent != current)
				      ? PT_ATTACHED : 0);
	if (capable(CAP_SYS_PTRACE))
		task->ptrace |= PT_PTRACE_CAP;
	task_unlock(task);

	write_lock_irq(&tasklist_lock);
	__ptrace_link(task, current);
	write_unlock_irq(&tasklist_lock);

	force_sig_specific(SIGSTOP, task);
	return 0;

bad:
	task_unlock(task);
	return retval;
}

int ptrace_detach(struct task_struct *child, unsigned int data)
{
	if (!valid_signal(data))
		return	-EIO;

	/* Architecture-specific hardware disable .. */
	ptrace_disable(child);

	/* .. re-parent .. */
	child->exit_code = data;

	write_lock_irq(&tasklist_lock);
	__ptrace_unlink(child);
	/* .. and wake it up. */
	if (child->exit_state != EXIT_ZOMBIE)
		wake_up_process(child);
	write_unlock_irq(&tasklist_lock);

	return 0;
}

/*
 * Access another process' address space.
 * Source/target buffer must be kernel space, 
 * Do not walk the page table directly, use get_user_pages
 */

int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
{
	struct mm_struct *mm;
	struct vm_area_struct *vma;
	struct page *page;
	void *old_buf = buf;

	mm = get_task_mm(tsk);
	if (!mm)
		return 0;

	down_read(&mm->mmap_sem);
	/* ignore errors, just check how much was sucessfully transfered */
	while (len) {
		int bytes, ret, offset;
		void *maddr;

		ret = get_user_pages(tsk, mm, addr, 1,
				write, 1, &page, &vma);
		if (ret <= 0)
			break;

		bytes = len;
		offset = addr & (PAGE_SIZE-1);
		if (bytes > PAGE_SIZE-offset)
			bytes = PAGE_SIZE-offset;

		maddr = kmap(page);
		if (write) {
			copy_to_user_page(vma, page, addr,
					  maddr + offset, buf, bytes);
			set_page_dirty_lock(page);
		} else {
			copy_from_user_page(vma, page, addr,
					    buf, maddr + offset, bytes);
		}
		kunmap(page);
		page_cache_release(page);
		len -= bytes;
		buf += bytes;
		addr += bytes;
	}
	up_read(&mm->mmap_sem);
	mmput(mm);
	
	return buf - old_buf;
}

int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len)
{
	int copied = 0;

	while (len > 0) {
		char buf[128];
		int this_len, retval;

		this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
		retval = access_process_vm(tsk, src, buf, this_len, 0);
		if (!retval) {
			if (copied)
				break;
			return -EIO;
		}
		if (copy_to_user(dst, buf, retval))
			return -EFAULT;
		copied += retval;
		src += retval;
		dst += retval;
		len -= retval;			
	}
	return copied;
}

int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len)
{
	int copied = 0;

	while (len > 0) {
		char buf[128];
		int this_len, retval;

		this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
		if (copy_from_user(buf, src, this_len))
			return -EFAULT;
		retval = access_process_vm(tsk, dst, buf, this_len, 1);
		if (!retval) {
			if (copied)
				break;
			return -EIO;
		}
		copied += retval;
		src += retval;
		dst += retval;
		len -= retval;			
	}
	return copied;
}

static int ptrace_setoptions(struct task_struct *child, long data)
{
	child->ptrace &= ~PT_TRACE_MASK;

	if (data & PTRACE_O_TRACESYSGOOD)
		child->ptrace |= PT_TRACESYSGOOD;

	if (data & PTRACE_O_TRACEFORK)
		child->ptrace |= PT_TRACE_FORK;

	if (data & PTRACE_O_TRACEVFORK)
		child->ptrace |= PT_TRACE_VFORK;

	if (data & PTRACE_O_TRACECLONE)
		child->ptrace |= PT_TRACE_CLONE;

	if (data & PTRACE_O_TRACEEXEC)
		child->ptrace |= PT_TRACE_EXEC;

	if (data & PTRACE_O_TRACEVFORKDONE)
		child->ptrace |= PT_TRACE_VFORK_DONE;

	if (data & PTRACE_O_TRACEEXIT)
		child->ptrace |= PT_TRACE_EXIT;

	return (data & ~PTRACE_O_MASK) ? -EINVAL : 0;
}

static int ptrace_getsiginfo(struct task_struct *child, siginfo_t __user * data)
{
	siginfo_t lastinfo;
	int error = -ESRCH;

	read_lock(&tasklist_lock);
	if (likely(child->sighand != NULL)) {
		error = -EINVAL;
		spin_lock_irq(&child->sighand->siglock);
		if (likely(child->last_siginfo != NULL)) {
			lastinfo = *child->last_siginfo;
			error = 0;
		}
		spin_unlock_irq(&child->sighand->siglock);
	}
	read_unlock(&tasklist_lock);
	if (!error)
		return copy_siginfo_to_user(data, &lastinfo);
	return error;
}

static int ptrace_setsiginfo(struct task_struct *child, siginfo_t __user * data)
{
	siginfo_t newinfo;
	int error = -ESRCH;

	if (copy_from_user(&newinfo, data, sizeof (siginfo_t)))
		return -EFAULT;

	read_lock(&tasklist_lock);
	if (likely(child->sighand != NULL)) {
		error = -EINVAL;
		spin_lock_irq(&child->sighand->siglock);
		if (likely(child->last_siginfo != NULL)) {
			*child->last_siginfo = newinfo;
			error = 0;
		}
		spin_unlock_irq(&child->sighand->siglock);
	}
	read_unlock(&tasklist_lock);
	return error;
}

int ptrace_request(struct task_struct *child, long request,
		   long addr, long data)
{
	int ret = -EIO;

	switch (request) {
#ifdef PTRACE_OLDSETOPTIONS
	case PTRACE_OLDSETOPTIONS:
#endif
	case PTRACE_SETOPTIONS:
		ret = ptrace_setoptions(child, data);
		break;
	case PTRACE_GETEVENTMSG:
		ret = put_user(child->ptrace_message, (unsigned long __user *) data);
		break;
	case PTRACE_GETSIGINFO:
		ret = ptrace_getsiginfo(child, (siginfo_t __user *) data);
		break;
	case PTRACE_SETSIGINFO:
		ret = ptrace_setsiginfo(child, (siginfo_t __user *) data);
		break;
	default:
		break;
	}

	return ret;
}

#ifndef __ARCH_SYS_PTRACE
static int ptrace_get_task_struct(long request, long pid,
		struct task_struct **childp)
{
	struct task_struct *child;
	int ret;

	/*
	 * Callers use child == NULL as an indication to exit early even
	 * when the return value is 0, so make sure it is non-NULL here.
	 */
	*childp = NULL;

	if (request == PTRACE_TRACEME) {
		/*
		 * Are we already being traced?
		 */
		if (current->ptrace & PT_PTRACED)
			return -EPERM;
		ret = security_ptrace(current->parent, current);
		if (ret)
			return -EPERM;
		/*
		 * Set the ptrace bit in the process ptrace flags.
		 */
		current->ptrace |= PT_PTRACED;
		return 0;
	}

	/*
	 * You may not mess with init
	 */
	if (pid == 1)
		return -EPERM;

	ret = -ESRCH;
	read_lock(&tasklist_lock);
	child = find_task_by_pid(pid);
	if (child)
		get_task_struct(child);
	read_unlock(&tasklist_lock);
	if (!child)
		return -ESRCH;

	*childp = child;
	return 0;
}

asmlinkage long sys_ptrace(long request, long pid, long addr, long data)
{
	struct task_struct *child;
	long ret;

	/*
	 * This lock_kernel fixes a subtle race with suid exec
	 */
	lock_kernel();
	ret = ptrace_get_task_struct(request, pid, &child);
	if (!child)
		goto out;

	if (request == PTRACE_ATTACH) {
		ret = ptrace_attach(child);
		goto out;
	}

	ret = ptrace_check_attach(child, request == PTRACE_KILL);
	if (ret < 0)
		goto out_put_task_struct;

	ret = arch_ptrace(child, request, addr, data);
	if (ret < 0)
		goto out_put_task_struct;

 out_put_task_struct:
	put_task_struct(child);
 out:
	unlock_kernel();
	return ret;
}
#endif /* __ARCH_SYS_PTRACE */
Commit	Line	Data
1da177e4 LT	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/module.h>
	11	#include <linux/sched.h>
	12	#include <linux/errno.h>
	13	#include <linux/mm.h>
	14	#include <linux/highmem.h>
	15	#include <linux/pagemap.h>
	16	#include <linux/smp_lock.h>
	17	#include <linux/ptrace.h>
	18	#include <linux/security.h>
7ed20e1a	19	#include <linux/signal.h>
1da177e4 LT	20
	21	#include <asm/pgtable.h>
	22	#include <asm/uaccess.h>
	23
	24	/*
	25	* ptrace a task: make the debugger its new parent and
	26	* move it to the ptrace list.
	27	*
	28	* Must be called with the tasklist lock write-held.
	29	*/
	30	void __ptrace_link(task_t child, task_t new_parent)
	31	{
	32	if (!list_empty(&child->ptrace_list))
	33	BUG();
	34	if (child->parent == new_parent)
	35	return;
	36	list_add(&child->ptrace_list, &child->parent->ptrace_children);
	37	REMOVE_LINKS(child);
	38	child->parent = new_parent;
	39	SET_LINKS(child);
	40	}
	41
	42	/*
	43	* Turn a tracing stop into a normal stop now, since with no tracer there
	44	* would be no way to wake it up with SIGCONT or SIGKILL. If there was a
	45	* signal sent that would resume the child, but didn't because it was in
	46	* TASK_TRACED, resume it now.
	47	* Requires that irqs be disabled.
	48	*/
	49	void ptrace_untrace(task_t *child)
	50	{
	51	spin_lock(&child->sighand->siglock);
	52	if (child->state == TASK_TRACED) {
	53	if (child->signal->flags & SIGNAL_STOP_STOPPED) {
	54	child->state = TASK_STOPPED;
	55	} else {
	56	signal_wake_up(child, 1);
	57	}
	58	}
30e0fca6 AA	59	if (child->signal->flags & SIGNAL_GROUP_EXIT) {
	60	sigaddset(&child->pending.signal, SIGKILL);
	61	signal_wake_up(child, 1);
	62	}
1da177e4 LT	63	spin_unlock(&child->sighand->siglock);
	64	}
	65
	66	/*
	67	* unptrace a task: move it back to its original parent and
	68	* remove it from the ptrace list.
	69	*
	70	* Must be called with the tasklist lock write-held.
	71	*/
	72	void __ptrace_unlink(task_t *child)
	73	{
	74	if (!child->ptrace)
	75	BUG();
	76	child->ptrace = 0;
	77	if (!list_empty(&child->ptrace_list)) {
	78	list_del_init(&child->ptrace_list);
	79	REMOVE_LINKS(child);
	80	child->parent = child->real_parent;
	81	SET_LINKS(child);
	82	}
	83
30e0fca6	84	ptrace_untrace(child);
1da177e4 LT	85	}
	86
	87	/*
	88	* Check that we have indeed attached to the thing..
	89	*/
	90	int ptrace_check_attach(struct task_struct *child, int kill)
	91	{
	92	int ret = -ESRCH;
	93
	94	/*
	95	* We take the read lock around doing both checks to close a
	96	* possible race where someone else was tracing our child and
	97	* detached between these two checks. After this locked check,
	98	* we are sure that this is our traced child and that can only
	99	* be changed by us so it's not changing right after this.
	100	*/
	101	read_lock(&tasklist_lock);
	102	if ((child->ptrace & PT_PTRACED) && child->parent == current &&
	103	(!(child->ptrace & PT_ATTACHED) \|\| child->real_parent != current)
	104	&& child->signal != NULL) {
	105	ret = 0;
	106	spin_lock_irq(&child->sighand->siglock);
	107	if (child->state == TASK_STOPPED) {
	108	child->state = TASK_TRACED;
	109	} else if (child->state != TASK_TRACED && !kill) {
	110	ret = -ESRCH;
	111	}
	112	spin_unlock_irq(&child->sighand->siglock);
	113	}
	114	read_unlock(&tasklist_lock);
	115
	116	if (!ret && !kill) {
	117	wait_task_inactive(child);
	118	}
	119
	120	/* All systems go.. */
	121	return ret;
	122	}
	123
ab8d11be MS	124	static int may_attach(struct task_struct *task)
	125	{
	126	if (!task->mm)
	127	return -EPERM;
	128	if (((current->uid != task->euid) \|\|
	129	(current->uid != task->suid) \|\|
	130	(current->uid != task->uid) \|\|
	131	(current->gid != task->egid) \|\|
	132	(current->gid != task->sgid) \|\|
	133	(current->gid != task->gid)) && !capable(CAP_SYS_PTRACE))
	134	return -EPERM;
	135	smp_rmb();
	136	if (!task->mm->dumpable && !capable(CAP_SYS_PTRACE))
	137	return -EPERM;
	138
	139	return security_ptrace(current, task);
	140	}
	141
	142	int ptrace_may_attach(struct task_struct *task)
	143	{
	144	int err;
	145	task_lock(task);
	146	err = may_attach(task);
	147	task_unlock(task);
	148	return !err;
	149	}
	150
1da177e4 LT	151	int ptrace_attach(struct task_struct *task)
	152	{
	153	int retval;
	154	task_lock(task);
	155	retval = -EPERM;
	156	if (task->pid <= 1)
	157	goto bad;
28d838cc	158	if (task->tgid == current->tgid)
1da177e4	159	goto bad;
1da177e4 LT	160	/* the same process cannot be attached many times */
	161	if (task->ptrace & PT_PTRACED)
	162	goto bad;
ab8d11be	163	retval = may_attach(task);
1da177e4 LT	164	if (retval)
	165	goto bad;
	166
	167	/* Go */
	168	task->ptrace \|= PT_PTRACED \| ((task->real_parent != current)
	169	? PT_ATTACHED : 0);
	170	if (capable(CAP_SYS_PTRACE))
	171	task->ptrace \|= PT_PTRACE_CAP;
	172	task_unlock(task);
	173
	174	write_lock_irq(&tasklist_lock);
	175	__ptrace_link(task, current);
	176	write_unlock_irq(&tasklist_lock);
	177
	178	force_sig_specific(SIGSTOP, task);
	179	return 0;
	180
	181	bad:
	182	task_unlock(task);
	183	return retval;
	184	}
	185
	186	int ptrace_detach(struct task_struct *child, unsigned int data)
	187	{
7ed20e1a	188	if (!valid_signal(data))
1da177e4 LT	189	return -EIO;
	190
	191	/* Architecture-specific hardware disable .. */
	192	ptrace_disable(child);
	193
	194	/* .. re-parent .. */
	195	child->exit_code = data;
	196
	197	write_lock_irq(&tasklist_lock);
	198	__ptrace_unlink(child);
	199	/* .. and wake it up. */
	200	if (child->exit_state != EXIT_ZOMBIE)
	201	wake_up_process(child);
	202	write_unlock_irq(&tasklist_lock);
	203
	204	return 0;
	205	}
	206
	207	/*
	208	* Access another process' address space.
	209	* Source/target buffer must be kernel space,
	210	* Do not walk the page table directly, use get_user_pages
	211	*/
	212
	213	int access_process_vm(struct task_struct tsk, unsigned long addr, void buf, int len, int write)
	214	{
	215	struct mm_struct *mm;
	216	struct vm_area_struct *vma;
	217	struct page *page;
	218	void *old_buf = buf;
	219
	220	mm = get_task_mm(tsk);
	221	if (!mm)
	222	return 0;
	223
	224	down_read(&mm->mmap_sem);
	225	/* ignore errors, just check how much was sucessfully transfered */
	226	while (len) {
	227	int bytes, ret, offset;
	228	void *maddr;
	229
	230	ret = get_user_pages(tsk, mm, addr, 1,
	231	write, 1, &page, &vma);
	232	if (ret <= 0)
	233	break;
	234
	235	bytes = len;
	236	offset = addr & (PAGE_SIZE-1);
	237	if (bytes > PAGE_SIZE-offset)
	238	bytes = PAGE_SIZE-offset;
	239
	240	maddr = kmap(page);
	241	if (write) {
	242	copy_to_user_page(vma, page, addr,
	243	maddr + offset, buf, bytes);
	244	set_page_dirty_lock(page);
	245	} else {
	246	copy_from_user_page(vma, page, addr,
	247	buf, maddr + offset, bytes);
	248	}
	249	kunmap(page);
	250	page_cache_release(page);
	251	len -= bytes;
	252	buf += bytes;
253	addr += bytes;
254	}
255	up_read(&mm->mmap_sem);
256	mmput(mm);
257
258	return buf - old_buf;
259	}
260
261	int ptrace_readdata(struct task_struct tsk, unsigned long src, char __user dst, int len)
262	{
263	int copied = 0;
264
265	while (len > 0) {
266	char buf[128];
267	int this_len, retval;
268
269	this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
270	retval = access_process_vm(tsk, src, buf, this_len, 0);
271	if (!retval) {
272	if (copied)
273	break;
274	return -EIO;
275	}
276	if (copy_to_user(dst, buf, retval))
277	return -EFAULT;
278	copied += retval;
279	src += retval;
280	dst += retval;
281	len -= retval;
282	}
283	return copied;
284	}
285
286	int ptrace_writedata(struct task_struct tsk, char __user src, unsigned long dst, int len)
287	{
288	int copied = 0;
289
290	while (len > 0) {
291	char buf[128];
292	int this_len, retval;
293
294	this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
295	if (copy_from_user(buf, src, this_len))
296	return -EFAULT;
297	retval = access_process_vm(tsk, dst, buf, this_len, 1);
298	if (!retval) {
299	if (copied)
300	break;
301	return -EIO;
302	}
303	copied += retval;
304	src += retval;
305	dst += retval;
306	len -= retval;
307	}
308	return copied;
309	}
310
311	static int ptrace_setoptions(struct task_struct *child, long data)
312	{
313	child->ptrace &= ~PT_TRACE_MASK;
314
315	if (data & PTRACE_O_TRACESYSGOOD)
316	child->ptrace \|= PT_TRACESYSGOOD;
317
318	if (data & PTRACE_O_TRACEFORK)
319	child->ptrace \|= PT_TRACE_FORK;
320
321	if (data & PTRACE_O_TRACEVFORK)
322	child->ptrace \|= PT_TRACE_VFORK;
323
324	if (data & PTRACE_O_TRACECLONE)
325	child->ptrace \|= PT_TRACE_CLONE;
326
327	if (data & PTRACE_O_TRACEEXEC)
328	child->ptrace \|= PT_TRACE_EXEC;
329
330	if (data & PTRACE_O_TRACEVFORKDONE)
331	child->ptrace \|= PT_TRACE_VFORK_DONE;
332
333	if (data & PTRACE_O_TRACEEXIT)
334	child->ptrace \|= PT_TRACE_EXIT;
335
336	return (data & ~PTRACE_O_MASK) ? -EINVAL : 0;
337	}
338
339	static int ptrace_getsiginfo(struct task_struct child, siginfo_t __user data)
340	{
341	siginfo_t lastinfo;
342	int error = -ESRCH;
343
344	read_lock(&tasklist_lock);
345	if (likely(child->sighand != NULL)) {
346	error = -EINVAL;
347	spin_lock_irq(&child->sighand->siglock);
348	if (likely(child->last_siginfo != NULL)) {
349	lastinfo = *child->last_siginfo;
350	error = 0;
351	}
352	spin_unlock_irq(&child->sighand->siglock);
353	}
354	read_unlock(&tasklist_lock);
355	if (!error)
356	return copy_siginfo_to_user(data, &lastinfo);
357	return error;
358	}
359
360	static int ptrace_setsiginfo(struct task_struct child, siginfo_t __user data)
361	{
362	siginfo_t newinfo;
363	int error = -ESRCH;
364
365	if (copy_from_user(&newinfo, data, sizeof (siginfo_t)))
366	return -EFAULT;
367
368	read_lock(&tasklist_lock);
369	if (likely(child->sighand != NULL)) {
370	error = -EINVAL;
371	spin_lock_irq(&child->sighand->siglock);
372	if (likely(child->last_siginfo != NULL)) {
373	*child->last_siginfo = newinfo;
374	error = 0;
375	}
376	spin_unlock_irq(&child->sighand->siglock);
377	}
378	read_unlock(&tasklist_lock);
379	return error;
380	}
381
382	int ptrace_request(struct task_struct *child, long request,
383	long addr, long data)
384	{
385	int ret = -EIO;
386
387	switch (request) {
388	#ifdef PTRACE_OLDSETOPTIONS
389	case PTRACE_OLDSETOPTIONS:
390	#endif
391	case PTRACE_SETOPTIONS:
392	ret = ptrace_setoptions(child, data);
393	break;
394	case PTRACE_GETEVENTMSG:
395	ret = put_user(child->ptrace_message, (unsigned long __user *) data);
396	break;
397	case PTRACE_GETSIGINFO:
398	ret = ptrace_getsiginfo(child, (siginfo_t __user *) data);
399	break;
400	case PTRACE_SETSIGINFO:
401	ret = ptrace_setsiginfo(child, (siginfo_t __user *) data);
402	break;
403	default:
404	break;
405	}
406
407	return ret;
408	}
481bed45 CH	409
	410	#ifndef __ARCH_SYS_PTRACE
	411	static int ptrace_get_task_struct(long request, long pid,
	412	struct task_struct **childp)
	413	{
	414	struct task_struct *child;
	415	int ret;
	416
	417	/*
	418	* Callers use child == NULL as an indication to exit early even
	419	* when the return value is 0, so make sure it is non-NULL here.
	420	*/
	421	*childp = NULL;
	422
	423	if (request == PTRACE_TRACEME) {
	424	/*
	425	* Are we already being traced?
	426	*/
	427	if (current->ptrace & PT_PTRACED)
	428	return -EPERM;
	429	ret = security_ptrace(current->parent, current);
	430	if (ret)
	431	return -EPERM;
	432	/*
	433	* Set the ptrace bit in the process ptrace flags.
	434	*/
	435	current->ptrace \|= PT_PTRACED;
	436	return 0;
	437	}
	438
	439	/*
	440	* You may not mess with init
	441	*/
	442	if (pid == 1)
	443	return -EPERM;
	444
	445	ret = -ESRCH;
	446	read_lock(&tasklist_lock);
	447	child = find_task_by_pid(pid);
	448	if (child)
	449	get_task_struct(child);
	450	read_unlock(&tasklist_lock);
	451	if (!child)
	452	return -ESRCH;
	453
	454	*childp = child;
	455	return 0;
	456	}
	457
	458	asmlinkage long sys_ptrace(long request, long pid, long addr, long data)
	459	{
	460	struct task_struct *child;
	461	long ret;
	462
	463	/*
	464	* This lock_kernel fixes a subtle race with suid exec
	465	*/
	466	lock_kernel();
	467	ret = ptrace_get_task_struct(request, pid, &child);
	468	if (!child)
	469	goto out;
	470
	471	if (request == PTRACE_ATTACH) {
	472	ret = ptrace_attach(child);
473	goto out;
474	}
475
476	ret = ptrace_check_attach(child, request == PTRACE_KILL);
477	if (ret < 0)
478	goto out_put_task_struct;
479
480	ret = arch_ptrace(child, request, addr, data);
481	if (ret < 0)
482	goto out_put_task_struct;
483
484	out_put_task_struct:
485	put_task_struct(child);
486	out:
487	unlock_kernel();
488	return ret;
489	}
490	#endif /* __ARCH_SYS_PTRACE */