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

/*
 * linux/kernel/futex_compat.c
 *
 * Futex compatibililty routines.
 *
 * Copyright 2006, Red Hat, Inc., Ingo Molnar
 */

#include <linux/linkage.h>
#include <linux/compat.h>
#include <linux/futex.h>

#include <asm/uaccess.h>


/*
 * Fetch a robust-list pointer. Bit 0 signals PI futexes:
 */
static inline int
fetch_robust_entry(compat_uptr_t *uentry, struct robust_list __user **entry,
		   compat_uptr_t *head, int *pi)
{
	if (get_user(*uentry, head))
		return -EFAULT;

	*entry = compat_ptr((*uentry) & ~1);
	*pi = (unsigned int)(*uentry) & 1;

	return 0;
}

/*
 * Walk curr->robust_list (very carefully, it's a userspace list!)
 * and mark any locks found there dead, and notify any waiters.
 *
 * We silently return on any sign of list-walking problem.
 */
void compat_exit_robust_list(struct task_struct *curr)
{
	struct compat_robust_list_head __user *head = curr->compat_robust_list;
	struct robust_list __user *entry, *pending;
	unsigned int limit = ROBUST_LIST_LIMIT, pi, pip;
	compat_uptr_t uentry, upending;
	compat_long_t futex_offset;

	/*
	 * Fetch the list head (which was registered earlier, via
	 * sys_set_robust_list()):
	 */
	if (fetch_robust_entry(&uentry, &entry, &head->list.next, &pi))
		return;
	/*
	 * Fetch the relative futex offset:
	 */
	if (get_user(futex_offset, &head->futex_offset))
		return;
	/*
	 * Fetch any possibly pending lock-add first, and handle it
	 * if it exists:
	 */
	if (fetch_robust_entry(&upending, &pending,
			       &head->list_op_pending, &pip))
		return;
	if (upending)
		handle_futex_death((void *)pending + futex_offset, curr, pip);

	while (compat_ptr(uentry) != &head->list) {
		/*
		 * A pending lock might already be on the list, so
		 * dont process it twice:
		 */
		if (entry != pending)
			if (handle_futex_death((void *)entry + futex_offset,
						curr, pi))
				return;

		/*
		 * Fetch the next entry in the list:
		 */
		if (fetch_robust_entry(&uentry, &entry,
				       (compat_uptr_t *)&entry->next, &pi))
			return;
		/*
		 * Avoid excessively long or circular lists:
		 */
		if (!--limit)
			break;

		cond_resched();
	}
}

asmlinkage long
compat_sys_set_robust_list(struct compat_robust_list_head __user *head,
			   compat_size_t len)
{
	if (unlikely(len != sizeof(*head)))
		return -EINVAL;

	current->compat_robust_list = head;

	return 0;
}

asmlinkage long
compat_sys_get_robust_list(int pid, compat_uptr_t *head_ptr,
			   compat_size_t __user *len_ptr)
{
	struct compat_robust_list_head *head;
	unsigned long ret;

	if (!pid)
		head = current->compat_robust_list;
	else {
		struct task_struct *p;

		ret = -ESRCH;
		read_lock(&tasklist_lock);
		p = find_task_by_pid(pid);
		if (!p)
			goto err_unlock;
		ret = -EPERM;
		if ((current->euid != p->euid) && (current->euid != p->uid) &&
				!capable(CAP_SYS_PTRACE))
			goto err_unlock;
		head = p->compat_robust_list;
		read_unlock(&tasklist_lock);
	}

	if (put_user(sizeof(*head), len_ptr))
		return -EFAULT;
	return put_user(ptr_to_compat(head), head_ptr);

err_unlock:
	read_unlock(&tasklist_lock);

	return ret;
}

asmlinkage long compat_sys_futex(u32 __user *uaddr, int op, u32 val,
		struct compat_timespec __user *utime, u32 __user *uaddr2,
		u32 val3)
{
	struct timespec t;
	unsigned long timeout = MAX_SCHEDULE_TIMEOUT;
	int val2 = 0;

	if (utime && (op == FUTEX_WAIT || op == FUTEX_LOCK_PI)) {
		if (get_compat_timespec(&t, utime))
			return -EFAULT;
		if (!timespec_valid(&t))
			return -EINVAL;
		if (op == FUTEX_WAIT)
			timeout = timespec_to_jiffies(&t) + 1;
		else {
			timeout = t.tv_sec;
			val2 = t.tv_nsec;
		}
	}
	if (op == FUTEX_REQUEUE || op == FUTEX_CMP_REQUEUE)
		val2 = (int) (unsigned long) utime;

	return do_futex(uaddr, op, val, timeout, uaddr2, val2, val3);
}
Commit	Line	Data
34f192c6 IM	1	/*
	2	* linux/kernel/futex_compat.c
	3	*
	4	* Futex compatibililty routines.
	5	*
	6	* Copyright 2006, Red Hat, Inc., Ingo Molnar
	7	*/
	8
	9	#include <linux/linkage.h>
	10	#include <linux/compat.h>
	11	#include <linux/futex.h>
	12
	13	#include <asm/uaccess.h>
	14
e3f2ddea IM	15
	16	/*
	17	* Fetch a robust-list pointer. Bit 0 signals PI futexes:
	18	*/
	19	static inline int
	20	fetch_robust_entry(compat_uptr_t uentry, struct robust_list __user *entry,
	21	compat_uptr_t head, int pi)
	22	{
	23	if (get_user(*uentry, head))
	24	return -EFAULT;
	25
	26	entry = compat_ptr((uentry) & ~1);
	27	pi = (unsigned int)(uentry) & 1;
	28
	29	return 0;
	30	}
	31
34f192c6 IM	32	/*
	33	* Walk curr->robust_list (very carefully, it's a userspace list!)
	34	* and mark any locks found there dead, and notify any waiters.
	35	*
	36	* We silently return on any sign of list-walking problem.
	37	*/
	38	void compat_exit_robust_list(struct task_struct *curr)
	39	{
	40	struct compat_robust_list_head __user *head = curr->compat_robust_list;
	41	struct robust_list __user entry, pending;
ce2c6b53	42	unsigned int limit = ROBUST_LIST_LIMIT, pi, pip;
34f192c6	43	compat_uptr_t uentry, upending;
34f192c6 IM	44	compat_long_t futex_offset;
	45
	46	/*
	47	* Fetch the list head (which was registered earlier, via
	48	* sys_set_robust_list()):
	49	*/
e3f2ddea	50	if (fetch_robust_entry(&uentry, &entry, &head->list.next, &pi))
34f192c6	51	return;
34f192c6 IM	52	/*
	53	* Fetch the relative futex offset:
	54	*/
	55	if (get_user(futex_offset, &head->futex_offset))
	56	return;
	57	/*
	58	* Fetch any possibly pending lock-add first, and handle it
	59	* if it exists:
	60	*/
e3f2ddea	61	if (fetch_robust_entry(&upending, &pending,
ce2c6b53	62	&head->list_op_pending, &pip))
34f192c6	63	return;
34f192c6	64	if (upending)
ce2c6b53	65	handle_futex_death((void *)pending + futex_offset, curr, pip);
34f192c6 IM	66
	67	while (compat_ptr(uentry) != &head->list) {
	68	/*
	69	* A pending lock might already be on the list, so
	70	* dont process it twice:
	71	*/
	72	if (entry != pending)
	73	if (handle_futex_death((void *)entry + futex_offset,
e3f2ddea	74	curr, pi))
34f192c6 IM	75	return;
	76
	77	/*
	78	* Fetch the next entry in the list:
	79	*/
e3f2ddea IM	80	if (fetch_robust_entry(&uentry, &entry,
e3f2ddea IM	81	(compat_uptr_t *)&entry->next, &pi))
34f192c6	82	return;
34f192c6 IM	83	/*
	84	* Avoid excessively long or circular lists:
	85	*/
	86	if (!--limit)
	87	break;
	88
	89	cond_resched();
	90	}
	91	}
	92
	93	asmlinkage long
	94	compat_sys_set_robust_list(struct compat_robust_list_head __user *head,
	95	compat_size_t len)
	96	{
	97	if (unlikely(len != sizeof(*head)))
	98	return -EINVAL;
	99
	100	current->compat_robust_list = head;
	101
	102	return 0;
	103	}
	104
	105	asmlinkage long
	106	compat_sys_get_robust_list(int pid, compat_uptr_t *head_ptr,
	107	compat_size_t __user *len_ptr)
	108	{
	109	struct compat_robust_list_head *head;
	110	unsigned long ret;
	111
	112	if (!pid)
	113	head = current->compat_robust_list;
	114	else {
	115	struct task_struct *p;
	116
	117	ret = -ESRCH;
	118	read_lock(&tasklist_lock);
	119	p = find_task_by_pid(pid);
	120	if (!p)
	121	goto err_unlock;
	122	ret = -EPERM;
	123	if ((current->euid != p->euid) && (current->euid != p->uid) &&
	124	!capable(CAP_SYS_PTRACE))
	125	goto err_unlock;
	126	head = p->compat_robust_list;
	127	read_unlock(&tasklist_lock);
	128	}
	129
	130	if (put_user(sizeof(*head), len_ptr))
	131	return -EFAULT;
	132	return put_user(ptr_to_compat(head), head_ptr);
	133
	134	err_unlock:
	135	read_unlock(&tasklist_lock);
	136
	137	return ret;
	138	}
	139
8f17d3a5	140	asmlinkage long compat_sys_futex(u32 __user *uaddr, int op, u32 val,
34f192c6	141	struct compat_timespec __user utime, u32 __user uaddr2,
8f17d3a5	142	u32 val3)
34f192c6 IM	143	{
	144	struct timespec t;
	145	unsigned long timeout = MAX_SCHEDULE_TIMEOUT;
	146	int val2 = 0;
	147
c87e2837	148	if (utime && (op == FUTEX_WAIT \|\| op == FUTEX_LOCK_PI)) {
34f192c6 IM	149	if (get_compat_timespec(&t, utime))
34f192c6 IM	150	return -EFAULT;
9741ef96 TG	151	if (!timespec_valid(&t))
9741ef96 TG	152	return -EINVAL;
c87e2837 IM	153	if (op == FUTEX_WAIT)
	154	timeout = timespec_to_jiffies(&t) + 1;
	155	else {
	156	timeout = t.tv_sec;
	157	val2 = t.tv_nsec;
	158	}
34f192c6	159	}
c87e2837	160	if (op == FUTEX_REQUEUE \|\| op == FUTEX_CMP_REQUEUE)
34f192c6 IM	161	val2 = (int) (unsigned long) utime;
34f192c6 IM	162
e2970f2f	163	return do_futex(uaddr, op, val, timeout, uaddr2, val2, val3);
34f192c6	164	}