[linux-2.6-block.git] / fs / signalfd.c

// SPDX-License-Identifier: GPL-2.0
/*
 *  fs/signalfd.c
 *
 *  Copyright (C) 2003  Linus Torvalds
 *
 *  Mon Mar 5, 2007: Davide Libenzi <davidel@xmailserver.org>
 *      Changed ->read() to return a siginfo strcture instead of signal number.
 *      Fixed locking in ->poll().
 *      Added sighand-detach notification.
 *      Added fd re-use in sys_signalfd() syscall.
 *      Now using anonymous inode source.
 *      Thanks to Oleg Nesterov for useful code review and suggestions.
 *      More comments and suggestions from Arnd Bergmann.
 *  Sat May 19, 2007: Davi E. M. Arnaut <davi@haxent.com.br>
 *      Retrieve multiple signals with one read() call
 *  Sun Jul 15, 2007: Davide Libenzi <davidel@xmailserver.org>
 *      Attach to the sighand only during read() and poll().
 */

#include <linux/file.h>
#include <linux/poll.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/signal.h>
#include <linux/list.h>
#include <linux/anon_inodes.h>
#include <linux/signalfd.h>
#include <linux/syscalls.h>
#include <linux/proc_fs.h>
#include <linux/compat.h>

void signalfd_cleanup(struct sighand_struct *sighand)
{
	wait_queue_head_t *wqh = &sighand->signalfd_wqh;
	/*
	 * The lockless check can race with remove_wait_queue() in progress,
	 * but in this case its caller should run under rcu_read_lock() and
	 * sighand_cachep is SLAB_TYPESAFE_BY_RCU, we can safely return.
	 */
	if (likely(!waitqueue_active(wqh)))
		return;

	/* wait_queue_entry_t->func(POLLFREE) should do remove_wait_queue() */
	wake_up_poll(wqh, EPOLLHUP | POLLFREE);
}

struct signalfd_ctx {
	sigset_t sigmask;
};

static int signalfd_release(struct inode *inode, struct file *file)
{
	kfree(file->private_data);
	return 0;
}

static __poll_t signalfd_poll(struct file *file, poll_table *wait)
{
	struct signalfd_ctx *ctx = file->private_data;
	__poll_t events = 0;

	poll_wait(file, &current->sighand->signalfd_wqh, wait);

	spin_lock_irq(&current->sighand->siglock);
	if (next_signal(&current->pending, &ctx->sigmask) ||
	    next_signal(&current->signal->shared_pending,
			&ctx->sigmask))
		events |= EPOLLIN;
	spin_unlock_irq(&current->sighand->siglock);

	return events;
}

/*
 * Copied from copy_siginfo_to_user() in kernel/signal.c
 */
static int signalfd_copyinfo(struct signalfd_siginfo __user *uinfo,
			     siginfo_t const *kinfo)
{
	long err;

	BUILD_BUG_ON(sizeof(struct signalfd_siginfo) != 128);

	/*
	 * Unused members should be zero ...
	 */
	err = __clear_user(uinfo, sizeof(*uinfo));

	/*
	 * If you change siginfo_t structure, please be sure
	 * this code is fixed accordingly.
	 */
	err |= __put_user(kinfo->si_signo, &uinfo->ssi_signo);
	err |= __put_user(kinfo->si_errno, &uinfo->ssi_errno);
	err |= __put_user(kinfo->si_code, &uinfo->ssi_code);
	switch (siginfo_layout(kinfo->si_signo, kinfo->si_code)) {
	case SIL_KILL:
		err |= __put_user(kinfo->si_pid, &uinfo->ssi_pid);
		err |= __put_user(kinfo->si_uid, &uinfo->ssi_uid);
		break;
	case SIL_TIMER:
		 err |= __put_user(kinfo->si_tid, &uinfo->ssi_tid);
		 err |= __put_user(kinfo->si_overrun, &uinfo->ssi_overrun);
		 err |= __put_user((long) kinfo->si_ptr, &uinfo->ssi_ptr);
		 err |= __put_user(kinfo->si_int, &uinfo->ssi_int);
		break;
	case SIL_POLL:
		err |= __put_user(kinfo->si_band, &uinfo->ssi_band);
		err |= __put_user(kinfo->si_fd, &uinfo->ssi_fd);
		break;
	case SIL_FAULT:
		err |= __put_user((long) kinfo->si_addr, &uinfo->ssi_addr);
#ifdef __ARCH_SI_TRAPNO
		err |= __put_user(kinfo->si_trapno, &uinfo->ssi_trapno);
#endif
#ifdef BUS_MCEERR_AO
		/*
		 * Other callers might not initialize the si_lsb field,
		 * so check explicitly for the right codes here.
		 */
		if (kinfo->si_signo == SIGBUS &&
		     kinfo->si_code == BUS_MCEERR_AO)
			err |= __put_user((short) kinfo->si_addr_lsb,
					  &uinfo->ssi_addr_lsb);
#endif
#ifdef BUS_MCEERR_AR
		/*
		 * Other callers might not initialize the si_lsb field,
		 * so check explicitly for the right codes here.
		 */
		if (kinfo->si_signo == SIGBUS &&
		    kinfo->si_code == BUS_MCEERR_AR)
			err |= __put_user((short) kinfo->si_addr_lsb,
					  &uinfo->ssi_addr_lsb);
#endif
		break;
	case SIL_CHLD:
		err |= __put_user(kinfo->si_pid, &uinfo->ssi_pid);
		err |= __put_user(kinfo->si_uid, &uinfo->ssi_uid);
		err |= __put_user(kinfo->si_status, &uinfo->ssi_status);
		err |= __put_user(kinfo->si_utime, &uinfo->ssi_utime);
		err |= __put_user(kinfo->si_stime, &uinfo->ssi_stime);
		break;
	case SIL_RT:
	default:
		/*
		 * This case catches also the signals queued by sigqueue().
		 */
		err |= __put_user(kinfo->si_pid, &uinfo->ssi_pid);
		err |= __put_user(kinfo->si_uid, &uinfo->ssi_uid);
		err |= __put_user((long) kinfo->si_ptr, &uinfo->ssi_ptr);
		err |= __put_user(kinfo->si_int, &uinfo->ssi_int);
		break;
	}

	return err ? -EFAULT: sizeof(*uinfo);
}

static ssize_t signalfd_dequeue(struct signalfd_ctx *ctx, siginfo_t *info,
				int nonblock)
{
	ssize_t ret;
	DECLARE_WAITQUEUE(wait, current);

	spin_lock_irq(&current->sighand->siglock);
	ret = dequeue_signal(current, &ctx->sigmask, info);
	switch (ret) {
	case 0:
		if (!nonblock)
			break;
		ret = -EAGAIN;
	default:
		spin_unlock_irq(&current->sighand->siglock);
		return ret;
	}

	add_wait_queue(&current->sighand->signalfd_wqh, &wait);
	for (;;) {
		set_current_state(TASK_INTERRUPTIBLE);
		ret = dequeue_signal(current, &ctx->sigmask, info);
		if (ret != 0)
			break;
		if (signal_pending(current)) {
			ret = -ERESTARTSYS;
			break;
		}
		spin_unlock_irq(&current->sighand->siglock);
		schedule();
		spin_lock_irq(&current->sighand->siglock);
	}
	spin_unlock_irq(&current->sighand->siglock);

	remove_wait_queue(&current->sighand->signalfd_wqh, &wait);
	__set_current_state(TASK_RUNNING);

	return ret;
}

/*
 * Returns a multiple of the size of a "struct signalfd_siginfo", or a negative
 * error code. The "count" parameter must be at least the size of a
 * "struct signalfd_siginfo".
 */
static ssize_t signalfd_read(struct file *file, char __user *buf, size_t count,
			     loff_t *ppos)
{
	struct signalfd_ctx *ctx = file->private_data;
	struct signalfd_siginfo __user *siginfo;
	int nonblock = file->f_flags & O_NONBLOCK;
	ssize_t ret, total = 0;
	siginfo_t info;

	count /= sizeof(struct signalfd_siginfo);
	if (!count)
		return -EINVAL;

	siginfo = (struct signalfd_siginfo __user *) buf;
	do {
		ret = signalfd_dequeue(ctx, &info, nonblock);
		if (unlikely(ret <= 0))
			break;
		ret = signalfd_copyinfo(siginfo, &info);
		if (ret < 0)
			break;
		siginfo++;
		total += ret;
		nonblock = 1;
	} while (--count);

	return total ? total: ret;
}

#ifdef CONFIG_PROC_FS
static void signalfd_show_fdinfo(struct seq_file *m, struct file *f)
{
	struct signalfd_ctx *ctx = f->private_data;
	sigset_t sigmask;

	sigmask = ctx->sigmask;
	signotset(&sigmask);
	render_sigset_t(m, "sigmask:\t", &sigmask);
}
#endif

static const struct file_operations signalfd_fops = {
#ifdef CONFIG_PROC_FS
	.show_fdinfo	= signalfd_show_fdinfo,
#endif
	.release	= signalfd_release,
	.poll		= signalfd_poll,
	.read		= signalfd_read,
	.llseek		= noop_llseek,
};

static int do_signalfd4(int ufd, sigset_t *mask, int flags)
{
	struct signalfd_ctx *ctx;

	/* Check the SFD_* constants for consistency.  */
	BUILD_BUG_ON(SFD_CLOEXEC != O_CLOEXEC);
	BUILD_BUG_ON(SFD_NONBLOCK != O_NONBLOCK);

	if (flags & ~(SFD_CLOEXEC | SFD_NONBLOCK))
		return -EINVAL;

	sigdelsetmask(mask, sigmask(SIGKILL) | sigmask(SIGSTOP));
	signotset(mask);

	if (ufd == -1) {
		ctx = kmalloc(sizeof(*ctx), GFP_KERNEL);
		if (!ctx)
			return -ENOMEM;

		ctx->sigmask = *mask;

		/*
		 * When we call this, the initialization must be complete, since
		 * anon_inode_getfd() will install the fd.
		 */
		ufd = anon_inode_getfd("[signalfd]", &signalfd_fops, ctx,
				       O_RDWR | (flags & (O_CLOEXEC | O_NONBLOCK)));
		if (ufd < 0)
			kfree(ctx);
	} else {
		struct fd f = fdget(ufd);
		if (!f.file)
			return -EBADF;
		ctx = f.file->private_data;
		if (f.file->f_op != &signalfd_fops) {
			fdput(f);
			return -EINVAL;
		}
		spin_lock_irq(&current->sighand->siglock);
		ctx->sigmask = *mask;
		spin_unlock_irq(&current->sighand->siglock);

		wake_up(&current->sighand->signalfd_wqh);
		fdput(f);
	}

	return ufd;
}

SYSCALL_DEFINE4(signalfd4, int, ufd, sigset_t __user *, user_mask,
		size_t, sizemask, int, flags)
{
	sigset_t mask;

	if (sizemask != sizeof(sigset_t) ||
	    copy_from_user(&mask, user_mask, sizeof(mask)))
		return -EINVAL;
	return do_signalfd4(ufd, &mask, flags);
}

SYSCALL_DEFINE3(signalfd, int, ufd, sigset_t __user *, user_mask,
		size_t, sizemask)
{
	sigset_t mask;

	if (sizemask != sizeof(sigset_t) ||
	    copy_from_user(&mask, user_mask, sizeof(mask)))
		return -EINVAL;
	return do_signalfd4(ufd, &mask, 0);
}

#ifdef CONFIG_COMPAT
static long do_compat_signalfd4(int ufd,
			const compat_sigset_t __user *user_mask,
			compat_size_t sigsetsize, int flags)
{
	sigset_t mask;

	if (sigsetsize != sizeof(compat_sigset_t))
		return -EINVAL;
	if (get_compat_sigset(&mask, user_mask))
		return -EFAULT;
	return do_signalfd4(ufd, &mask, flags);
}

COMPAT_SYSCALL_DEFINE4(signalfd4, int, ufd,
		     const compat_sigset_t __user *, user_mask,
		     compat_size_t, sigsetsize,
		     int, flags)
{
	return do_compat_signalfd4(ufd, user_mask, sigsetsize, flags);
}

COMPAT_SYSCALL_DEFINE3(signalfd, int, ufd,
		     const compat_sigset_t __user *, user_mask,
		     compat_size_t, sigsetsize)
{
	return do_compat_signalfd4(ufd, user_mask, sigsetsize, 0);
}
#endif
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
fba2afaa DL	2	/*
	3	* fs/signalfd.c
	4	*
	5	* Copyright (C) 2003 Linus Torvalds
	6	*
	7	* Mon Mar 5, 2007: Davide Libenzi <davidel@xmailserver.org>
	8	* Changed ->read() to return a siginfo strcture instead of signal number.
	9	* Fixed locking in ->poll().
	10	* Added sighand-detach notification.
	11	* Added fd re-use in sys_signalfd() syscall.
	12	* Now using anonymous inode source.
	13	* Thanks to Oleg Nesterov for useful code review and suggestions.
	14	* More comments and suggestions from Arnd Bergmann.
b8fceee1	15	* Sat May 19, 2007: Davi E. M. Arnaut <davi@haxent.com.br>
b3762bfc	16	* Retrieve multiple signals with one read() call
b8fceee1 DL	17	* Sun Jul 15, 2007: Davide Libenzi <davidel@xmailserver.org>
b8fceee1 DL	18	* Attach to the sighand only during read() and poll().
fba2afaa DL	19	*/
	20
	21	#include <linux/file.h>
	22	#include <linux/poll.h>
	23	#include <linux/init.h>
	24	#include <linux/fs.h>
	25	#include <linux/sched.h>
5a0e3ad6	26	#include <linux/slab.h>
fba2afaa DL	27	#include <linux/kernel.h>
	28	#include <linux/signal.h>
	29	#include <linux/list.h>
	30	#include <linux/anon_inodes.h>
	31	#include <linux/signalfd.h>
7ec37dfd	32	#include <linux/syscalls.h>
138d22b5	33	#include <linux/proc_fs.h>
7d197ed4	34	#include <linux/compat.h>
fba2afaa	35
d80e731e ON	36	void signalfd_cleanup(struct sighand_struct *sighand)
	37	{
	38	wait_queue_head_t *wqh = &sighand->signalfd_wqh;
971316f0 ON	39	/*
	40	* The lockless check can race with remove_wait_queue() in progress,
	41	* but in this case its caller should run under rcu_read_lock() and
5f0d5a3a	42	* sighand_cachep is SLAB_TYPESAFE_BY_RCU, we can safely return.
971316f0	43	*/
d80e731e ON	44	if (likely(!waitqueue_active(wqh)))
	45	return;
	46
ac6424b9	47	/* wait_queue_entry_t->func(POLLFREE) should do remove_wait_queue() */
a9a08845	48	wake_up_poll(wqh, EPOLLHUP \| POLLFREE);
d80e731e ON	49	}
d80e731e ON	50
fba2afaa	51	struct signalfd_ctx {
fba2afaa	52	sigset_t sigmask;
fba2afaa DL	53	};
fba2afaa DL	54
fba2afaa DL	55	static int signalfd_release(struct inode inode, struct file file)
fba2afaa DL	56	{
b8fceee1	57	kfree(file->private_data);
fba2afaa DL	58	return 0;
	59	}
	60
076ccb76	61	static __poll_t signalfd_poll(struct file file, poll_table wait)
fba2afaa DL	62	{
fba2afaa DL	63	struct signalfd_ctx *ctx = file->private_data;
076ccb76	64	__poll_t events = 0;
fba2afaa	65
b8fceee1	66	poll_wait(file, &current->sighand->signalfd_wqh, wait);
fba2afaa	67
b8fceee1 DL	68	spin_lock_irq(&current->sighand->siglock);
	69	if (next_signal(&current->pending, &ctx->sigmask) \|\|
	70	next_signal(&current->signal->shared_pending,
	71	&ctx->sigmask))
a9a08845	72	events \|= EPOLLIN;
b8fceee1	73	spin_unlock_irq(&current->sighand->siglock);
fba2afaa DL	74
	75	return events;
	76	}
	77
	78	/*
	79	* Copied from copy_siginfo_to_user() in kernel/signal.c
	80	*/
	81	static int signalfd_copyinfo(struct signalfd_siginfo __user *uinfo,
	82	siginfo_t const *kinfo)
	83	{
	84	long err;
	85
	86	BUILD_BUG_ON(sizeof(struct signalfd_siginfo) != 128);
	87
	88	/*
14e4a0f2	89	* Unused members should be zero ...
fba2afaa DL	90	*/
	91	err = __clear_user(uinfo, sizeof(*uinfo));
	92
	93	/*
	94	* If you change siginfo_t structure, please be sure
	95	* this code is fixed accordingly.
	96	*/
96358de6 DL	97	err \|= __put_user(kinfo->si_signo, &uinfo->ssi_signo);
96358de6 DL	98	err \|= __put_user(kinfo->si_errno, &uinfo->ssi_errno);
cc731525 EB	99	err \|= __put_user(kinfo->si_code, &uinfo->ssi_code);
	100	switch (siginfo_layout(kinfo->si_signo, kinfo->si_code)) {
	101	case SIL_KILL:
96358de6 DL	102	err \|= __put_user(kinfo->si_pid, &uinfo->ssi_pid);
96358de6 DL	103	err \|= __put_user(kinfo->si_uid, &uinfo->ssi_uid);
fba2afaa	104	break;
cc731525	105	case SIL_TIMER:
96358de6 DL	106	err \|= __put_user(kinfo->si_tid, &uinfo->ssi_tid);
	107	err \|= __put_user(kinfo->si_overrun, &uinfo->ssi_overrun);
	108	err \|= __put_user((long) kinfo->si_ptr, &uinfo->ssi_ptr);
a2a20c41	109	err \|= __put_user(kinfo->si_int, &uinfo->ssi_int);
fba2afaa	110	break;
cc731525	111	case SIL_POLL:
96358de6 DL	112	err \|= __put_user(kinfo->si_band, &uinfo->ssi_band);
96358de6 DL	113	err \|= __put_user(kinfo->si_fd, &uinfo->ssi_fd);
fba2afaa	114	break;
cc731525	115	case SIL_FAULT:
96358de6	116	err \|= __put_user((long) kinfo->si_addr, &uinfo->ssi_addr);
fba2afaa	117	#ifdef __ARCH_SI_TRAPNO
96358de6	118	err \|= __put_user(kinfo->si_trapno, &uinfo->ssi_trapno);
b8aeec34 HS	119	#endif
b8aeec34 HS	120	#ifdef BUS_MCEERR_AO
9026e820	121	/*
b8aeec34 HS	122	* Other callers might not initialize the si_lsb field,
	123	* so check explicitly for the right codes here.
	124	*/
3ead7c52	125	if (kinfo->si_signo == SIGBUS &&
9026e820 RD	126	kinfo->si_code == BUS_MCEERR_AO)
	127	err \|= __put_user((short) kinfo->si_addr_lsb,
	128	&uinfo->ssi_addr_lsb);
	129	#endif
	130	#ifdef BUS_MCEERR_AR
	131	/*
	132	* Other callers might not initialize the si_lsb field,
	133	* so check explicitly for the right codes here.
	134	*/
	135	if (kinfo->si_signo == SIGBUS &&
	136	kinfo->si_code == BUS_MCEERR_AR)
b8aeec34 HS	137	err \|= __put_user((short) kinfo->si_addr_lsb,
b8aeec34 HS	138	&uinfo->ssi_addr_lsb);
fba2afaa DL	139	#endif
fba2afaa DL	140	break;
cc731525	141	case SIL_CHLD:
96358de6 DL	142	err \|= __put_user(kinfo->si_pid, &uinfo->ssi_pid);
	143	err \|= __put_user(kinfo->si_uid, &uinfo->ssi_uid);
	144	err \|= __put_user(kinfo->si_status, &uinfo->ssi_status);
	145	err \|= __put_user(kinfo->si_utime, &uinfo->ssi_utime);
	146	err \|= __put_user(kinfo->si_stime, &uinfo->ssi_stime);
fba2afaa	147	break;
cc731525	148	case SIL_RT:
0859ab59 DL	149	default:
	150	/*
	151	* This case catches also the signals queued by sigqueue().
	152	*/
96358de6 DL	153	err \|= __put_user(kinfo->si_pid, &uinfo->ssi_pid);
96358de6 DL	154	err \|= __put_user(kinfo->si_uid, &uinfo->ssi_uid);
0859ab59 DL	155	err \|= __put_user((long) kinfo->si_ptr, &uinfo->ssi_ptr);
0859ab59 DL	156	err \|= __put_user(kinfo->si_int, &uinfo->ssi_int);
fba2afaa DL	157	break;
	158	}
	159
	160	return err ? -EFAULT: sizeof(*uinfo);
	161	}
	162
b3762bfc DA	163	static ssize_t signalfd_dequeue(struct signalfd_ctx ctx, siginfo_t info,
	164	int nonblock)
	165	{
	166	ssize_t ret;
b3762bfc DA	167	DECLARE_WAITQUEUE(wait, current);
b3762bfc DA	168
b8fceee1 DL	169	spin_lock_irq(&current->sighand->siglock);
b8fceee1 DL	170	ret = dequeue_signal(current, &ctx->sigmask, info);
b3762bfc DA	171	switch (ret) {
	172	case 0:
	173	if (!nonblock)
	174	break;
	175	ret = -EAGAIN;
	176	default:
b8fceee1	177	spin_unlock_irq(&current->sighand->siglock);
b3762bfc DA	178	return ret;
	179	}
	180
b8fceee1	181	add_wait_queue(&current->sighand->signalfd_wqh, &wait);
b3762bfc DA	182	for (;;) {
b3762bfc DA	183	set_current_state(TASK_INTERRUPTIBLE);
b8fceee1	184	ret = dequeue_signal(current, &ctx->sigmask, info);
b3762bfc DA	185	if (ret != 0)
	186	break;
	187	if (signal_pending(current)) {
	188	ret = -ERESTARTSYS;
	189	break;
	190	}
b8fceee1	191	spin_unlock_irq(&current->sighand->siglock);
b3762bfc	192	schedule();
b8fceee1	193	spin_lock_irq(&current->sighand->siglock);
b3762bfc	194	}
b8fceee1	195	spin_unlock_irq(&current->sighand->siglock);
b3762bfc	196
b8fceee1	197	remove_wait_queue(&current->sighand->signalfd_wqh, &wait);
b3762bfc DA	198	__set_current_state(TASK_RUNNING);
	199
	200	return ret;
	201	}
	202
fba2afaa	203	/*
b8fceee1 DL	204	* Returns a multiple of the size of a "struct signalfd_siginfo", or a negative
	205	* error code. The "count" parameter must be at least the size of a
	206	* "struct signalfd_siginfo".
fba2afaa DL	207	*/
	208	static ssize_t signalfd_read(struct file file, char __user buf, size_t count,
	209	loff_t *ppos)
	210	{
	211	struct signalfd_ctx *ctx = file->private_data;
b3762bfc DA	212	struct signalfd_siginfo __user *siginfo;
	213	int nonblock = file->f_flags & O_NONBLOCK;
	214	ssize_t ret, total = 0;
fba2afaa	215	siginfo_t info;
fba2afaa	216
b3762bfc DA	217	count /= sizeof(struct signalfd_siginfo);
b3762bfc DA	218	if (!count)
fba2afaa	219	return -EINVAL;
fba2afaa	220
b3762bfc	221	siginfo = (struct signalfd_siginfo __user *) buf;
b3762bfc DA	222	do {
	223	ret = signalfd_dequeue(ctx, &info, nonblock);
	224	if (unlikely(ret <= 0))
	225	break;
	226	ret = signalfd_copyinfo(siginfo, &info);
	227	if (ret < 0)
	228	break;
	229	siginfo++;
	230	total += ret;
	231	nonblock = 1;
	232	} while (--count);
	233
b8fceee1	234	return total ? total: ret;
fba2afaa DL	235	}
fba2afaa DL	236
138d22b5	237	#ifdef CONFIG_PROC_FS
a3816ab0	238	static void signalfd_show_fdinfo(struct seq_file m, struct file f)
138d22b5 CG	239	{
	240	struct signalfd_ctx *ctx = f->private_data;
	241	sigset_t sigmask;
	242
	243	sigmask = ctx->sigmask;
	244	signotset(&sigmask);
	245	render_sigset_t(m, "sigmask:\t", &sigmask);
138d22b5 CG	246	}
	247	#endif
	248
fba2afaa	249	static const struct file_operations signalfd_fops = {
138d22b5 CG	250	#ifdef CONFIG_PROC_FS
	251	.show_fdinfo = signalfd_show_fdinfo,
	252	#endif
fba2afaa DL	253	.release = signalfd_release,
	254	.poll = signalfd_poll,
	255	.read = signalfd_read,
6038f373	256	.llseek = noop_llseek,
fba2afaa DL	257	};
fba2afaa DL	258
5ed0127f	259	static int do_signalfd4(int ufd, sigset_t *mask, int flags)
fba2afaa	260	{
fba2afaa	261	struct signalfd_ctx *ctx;
fba2afaa	262
e38b36f3 UD	263	/* Check the SFD_* constants for consistency. */
	264	BUILD_BUG_ON(SFD_CLOEXEC != O_CLOEXEC);
	265	BUILD_BUG_ON(SFD_NONBLOCK != O_NONBLOCK);
	266
5fb5e049	267	if (flags & ~(SFD_CLOEXEC \| SFD_NONBLOCK))
9deb27ba UD	268	return -EINVAL;
9deb27ba UD	269
5ed0127f AV	270	sigdelsetmask(mask, sigmask(SIGKILL) \| sigmask(SIGSTOP));
5ed0127f AV	271	signotset(mask);
fba2afaa DL	272
	273	if (ufd == -1) {
	274	ctx = kmalloc(sizeof(*ctx), GFP_KERNEL);
	275	if (!ctx)
	276	return -ENOMEM;
	277
5ed0127f	278	ctx->sigmask = *mask;
fba2afaa DL	279
	280	/*
	281	* When we call this, the initialization must be complete, since
	282	* anon_inode_getfd() will install the fd.
	283	*/
7d9dbca3	284	ufd = anon_inode_getfd("[signalfd]", &signalfd_fops, ctx,
628ff7c1	285	O_RDWR \| (flags & (O_CLOEXEC \| O_NONBLOCK)));
2030a42c AV	286	if (ufd < 0)
2030a42c AV	287	kfree(ctx);
fba2afaa	288	} else {
2903ff01 AV	289	struct fd f = fdget(ufd);
2903ff01 AV	290	if (!f.file)
fba2afaa	291	return -EBADF;
2903ff01 AV	292	ctx = f.file->private_data;
	293	if (f.file->f_op != &signalfd_fops) {
	294	fdput(f);
fba2afaa DL	295	return -EINVAL;
fba2afaa DL	296	}
b8fceee1	297	spin_lock_irq(&current->sighand->siglock);
5ed0127f	298	ctx->sigmask = *mask;
b8fceee1 DL	299	spin_unlock_irq(&current->sighand->siglock);
	300
	301	wake_up(&current->sighand->signalfd_wqh);
2903ff01	302	fdput(f);
fba2afaa DL	303	}
	304
	305	return ufd;
fba2afaa	306	}
9deb27ba	307
52fb6db0 DB	308	SYSCALL_DEFINE4(signalfd4, int, ufd, sigset_t __user *, user_mask,
	309	size_t, sizemask, int, flags)
	310	{
5ed0127f AV	311	sigset_t mask;
	312
	313	if (sizemask != sizeof(sigset_t) \|\|
	314	copy_from_user(&mask, user_mask, sizeof(mask)))
	315	return -EINVAL;
	316	return do_signalfd4(ufd, &mask, flags);
52fb6db0 DB	317	}
52fb6db0 DB	318
836f92ad HC	319	SYSCALL_DEFINE3(signalfd, int, ufd, sigset_t __user *, user_mask,
836f92ad HC	320	size_t, sizemask)
9deb27ba	321	{
5ed0127f AV	322	sigset_t mask;
	323
	324	if (sizemask != sizeof(sigset_t) \|\|
	325	copy_from_user(&mask, user_mask, sizeof(mask)))
	326	return -EINVAL;
	327	return do_signalfd4(ufd, &mask, 0);
9deb27ba	328	}
7d197ed4 AV	329
7d197ed4 AV	330	#ifdef CONFIG_COMPAT
570484bf	331	static long do_compat_signalfd4(int ufd,
5ed0127f	332	const compat_sigset_t __user *user_mask,
570484bf	333	compat_size_t sigsetsize, int flags)
7d197ed4	334	{
5ed0127f	335	sigset_t mask;
7d197ed4 AV	336
	337	if (sigsetsize != sizeof(compat_sigset_t))
	338	return -EINVAL;
5ed0127f	339	if (get_compat_sigset(&mask, user_mask))
7d197ed4	340	return -EFAULT;
5ed0127f	341	return do_signalfd4(ufd, &mask, flags);
7d197ed4 AV	342	}
7d197ed4 AV	343
570484bf	344	COMPAT_SYSCALL_DEFINE4(signalfd4, int, ufd,
5ed0127f	345	const compat_sigset_t __user *, user_mask,
570484bf DB	346	compat_size_t, sigsetsize,
	347	int, flags)
	348	{
5ed0127f	349	return do_compat_signalfd4(ufd, user_mask, sigsetsize, flags);
570484bf DB	350	}
570484bf DB	351
7d197ed4	352	COMPAT_SYSCALL_DEFINE3(signalfd, int, ufd,
5ed0127f	353	const compat_sigset_t __user *, user_mask,
7d197ed4 AV	354	compat_size_t, sigsetsize)
7d197ed4 AV	355	{
5ed0127f	356	return do_compat_signalfd4(ufd, user_mask, sigsetsize, 0);
7d197ed4 AV	357	}
7d197ed4 AV	358	#endif