[linux.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/nsproxy.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 __user *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, *next_entry, *pending;
	unsigned int limit = ROBUST_LIST_LIMIT, pi, next_pi, pip;
	compat_uptr_t uentry, next_uentry, upending;
	compat_long_t futex_offset;
	int rc;

	/*
	 * 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;

	next_entry = NULL;	/* avoid warning with gcc */
	while (entry != (struct robust_list __user *) &head->list) {
		/*
		 * Fetch the next entry in the list before calling
		 * handle_futex_death:
		 */
		rc = fetch_robust_entry(&next_uentry, &next_entry,
			(compat_uptr_t __user *)&entry->next, &next_pi);
		/*
		 * A pending lock might already be on the list, so
		 * dont process it twice:
		 */
		if (entry != pending)
			if (handle_futex_death((void __user *)entry + futex_offset,
						curr, pi))
				return;

		if (rc)
			return;
		uentry = next_uentry;
		entry = next_entry;
		pi = next_pi;
		/*
		 * Avoid excessively long or circular lists:
		 */
		if (!--limit)
			break;

		cond_resched();
	}
	if (pending)
		handle_futex_death((void __user *)pending + futex_offset,
				   curr, pip);
}

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 __user *head_ptr,
			   compat_size_t __user *len_ptr)
{
	struct compat_robust_list_head __user *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_vpid(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 ts;
	ktime_t t, *tp = NULL;
	int val2 = 0;
	int cmd = op & FUTEX_CMD_MASK;

	if (utime && (cmd == FUTEX_WAIT || cmd == FUTEX_LOCK_PI)) {
		if (get_compat_timespec(&ts, utime))
			return -EFAULT;
		if (!timespec_valid(&ts))
			return -EINVAL;

		t = timespec_to_ktime(ts);
		if (cmd == FUTEX_WAIT)
			t = ktime_add(ktime_get(), t);
		tp = &t;
	}
	if (cmd == FUTEX_REQUEUE || cmd == FUTEX_CMP_REQUEUE)
		val2 = (int) (unsigned long) utime;

	return do_futex(uaddr, op, val, tp, 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>
b488893a	11	#include <linux/nsproxy.h>
34f192c6 IM	12	#include <linux/futex.h>
	13
	14	#include <asm/uaccess.h>
	15
e3f2ddea IM	16
	17	/*
	18	* Fetch a robust-list pointer. Bit 0 signals PI futexes:
	19	*/
	20	static inline int
	21	fetch_robust_entry(compat_uptr_t uentry, struct robust_list __user *entry,
ba46df98	22	compat_uptr_t __user head, int pi)
e3f2ddea IM	23	{
	24	if (get_user(*uentry, head))
	25	return -EFAULT;
	26
	27	entry = compat_ptr((uentry) & ~1);
	28	pi = (unsigned int)(uentry) & 1;
	29
	30	return 0;
	31	}
	32
34f192c6 IM	33	/*
	34	* Walk curr->robust_list (very carefully, it's a userspace list!)
	35	* and mark any locks found there dead, and notify any waiters.
	36	*
	37	* We silently return on any sign of list-walking problem.
	38	*/
	39	void compat_exit_robust_list(struct task_struct *curr)
	40	{
	41	struct compat_robust_list_head __user *head = curr->compat_robust_list;
9f96cb1e MS	42	struct robust_list __user entry, next_entry, *pending;
	43	unsigned int limit = ROBUST_LIST_LIMIT, pi, next_pi, pip;
	44	compat_uptr_t uentry, next_uentry, upending;
34f192c6	45	compat_long_t futex_offset;
9f96cb1e	46	int rc;
34f192c6 IM	47
	48	/*
	49	* Fetch the list head (which was registered earlier, via
	50	* sys_set_robust_list()):
	51	*/
e3f2ddea	52	if (fetch_robust_entry(&uentry, &entry, &head->list.next, &pi))
34f192c6	53	return;
34f192c6 IM	54	/*
	55	* Fetch the relative futex offset:
	56	*/
	57	if (get_user(futex_offset, &head->futex_offset))
	58	return;
	59	/*
	60	* Fetch any possibly pending lock-add first, and handle it
	61	* if it exists:
	62	*/
e3f2ddea	63	if (fetch_robust_entry(&upending, &pending,
ce2c6b53	64	&head->list_op_pending, &pip))
34f192c6	65	return;
34f192c6	66
9f96cb1e	67	next_entry = NULL; /* avoid warning with gcc */
179c85ea	68	while (entry != (struct robust_list __user *) &head->list) {
9f96cb1e MS	69	/*
	70	* Fetch the next entry in the list before calling
	71	* handle_futex_death:
	72	*/
	73	rc = fetch_robust_entry(&next_uentry, &next_entry,
	74	(compat_uptr_t __user *)&entry->next, &next_pi);
34f192c6 IM	75	/*
	76	* A pending lock might already be on the list, so
	77	* dont process it twice:
	78	*/
	79	if (entry != pending)
ba46df98	80	if (handle_futex_death((void __user *)entry + futex_offset,
e3f2ddea	81	curr, pi))
34f192c6 IM	82	return;
34f192c6 IM	83
9f96cb1e	84	if (rc)
34f192c6	85	return;
9f96cb1e MS	86	uentry = next_uentry;
	87	entry = next_entry;
	88	pi = next_pi;
34f192c6 IM	89	/*
	90	* Avoid excessively long or circular lists:
	91	*/
	92	if (!--limit)
	93	break;
	94
	95	cond_resched();
	96	}
9f96cb1e MS	97	if (pending)
	98	handle_futex_death((void __user *)pending + futex_offset,
	99	curr, pip);
34f192c6 IM	100	}
	101
	102	asmlinkage long
	103	compat_sys_set_robust_list(struct compat_robust_list_head __user *head,
	104	compat_size_t len)
	105	{
	106	if (unlikely(len != sizeof(*head)))
	107	return -EINVAL;
	108
	109	current->compat_robust_list = head;
	110
	111	return 0;
	112	}
	113
	114	asmlinkage long
ba46df98	115	compat_sys_get_robust_list(int pid, compat_uptr_t __user *head_ptr,
34f192c6 IM	116	compat_size_t __user *len_ptr)
34f192c6 IM	117	{
ba46df98	118	struct compat_robust_list_head __user *head;
34f192c6 IM	119	unsigned long ret;
	120
	121	if (!pid)
	122	head = current->compat_robust_list;
	123	else {
	124	struct task_struct *p;
	125
	126	ret = -ESRCH;
	127	read_lock(&tasklist_lock);
228ebcbe	128	p = find_task_by_vpid(pid);
34f192c6 IM	129	if (!p)
	130	goto err_unlock;
	131	ret = -EPERM;
	132	if ((current->euid != p->euid) && (current->euid != p->uid) &&
	133	!capable(CAP_SYS_PTRACE))
	134	goto err_unlock;
	135	head = p->compat_robust_list;
	136	read_unlock(&tasklist_lock);
	137	}
	138
	139	if (put_user(sizeof(*head), len_ptr))
	140	return -EFAULT;
	141	return put_user(ptr_to_compat(head), head_ptr);
	142
	143	err_unlock:
	144	read_unlock(&tasklist_lock);
	145
	146	return ret;
	147	}
	148
8f17d3a5	149	asmlinkage long compat_sys_futex(u32 __user *uaddr, int op, u32 val,
34f192c6	150	struct compat_timespec __user utime, u32 __user uaddr2,
8f17d3a5	151	u32 val3)
34f192c6	152	{
c19384b5 PP	153	struct timespec ts;
c19384b5 PP	154	ktime_t t, *tp = NULL;
34f192c6	155	int val2 = 0;
f0ede66f	156	int cmd = op & FUTEX_CMD_MASK;
34f192c6	157
f0ede66f	158	if (utime && (cmd == FUTEX_WAIT \|\| cmd == FUTEX_LOCK_PI)) {
c19384b5	159	if (get_compat_timespec(&ts, utime))
34f192c6	160	return -EFAULT;
c19384b5	161	if (!timespec_valid(&ts))
9741ef96	162	return -EINVAL;
c19384b5 PP	163
c19384b5 PP	164	t = timespec_to_ktime(ts);
f0ede66f	165	if (cmd == FUTEX_WAIT)
c19384b5 PP	166	t = ktime_add(ktime_get(), t);
c19384b5 PP	167	tp = &t;
34f192c6	168	}
bd197234	169	if (cmd == FUTEX_REQUEUE \|\| cmd == FUTEX_CMP_REQUEUE)
34f192c6 IM	170	val2 = (int) (unsigned long) utime;
34f192c6 IM	171
c19384b5	172	return do_futex(uaddr, op, val, tp, uaddr2, val2, val3);
34f192c6	173	}