[thirdparty/kernel/stable.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)
{
	wake_up_pollfree(&sighand->signalfd_wqh);
}

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 iov_iter *to, kernel_siginfo_t const *kinfo)
{
	struct signalfd_siginfo new;

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

	/*
	 * Unused members should be zero ...
	 */
	memset(&new, 0, sizeof(new));

	/*
	 * If you change siginfo_t structure, please be sure
	 * this code is fixed accordingly.
	 */
	new.ssi_signo = kinfo->si_signo;
	new.ssi_errno = kinfo->si_errno;
	new.ssi_code  = kinfo->si_code;
	switch (siginfo_layout(kinfo->si_signo, kinfo->si_code)) {
	case SIL_KILL:
		new.ssi_pid = kinfo->si_pid;
		new.ssi_uid = kinfo->si_uid;
		break;
	case SIL_TIMER:
		new.ssi_tid = kinfo->si_tid;
		new.ssi_overrun = kinfo->si_overrun;
		new.ssi_ptr = (long) kinfo->si_ptr;
		new.ssi_int = kinfo->si_int;
		break;
	case SIL_POLL:
		new.ssi_band = kinfo->si_band;
		new.ssi_fd   = kinfo->si_fd;
		break;
	case SIL_FAULT_BNDERR:
	case SIL_FAULT_PKUERR:
	case SIL_FAULT_PERF_EVENT:
		/*
		 * Fall through to the SIL_FAULT case.  SIL_FAULT_BNDERR,
		 * SIL_FAULT_PKUERR, and SIL_FAULT_PERF_EVENT are only
		 * generated by faults that deliver them synchronously to
		 * userspace.  In case someone injects one of these signals
		 * and signalfd catches it treat it as SIL_FAULT.
		 */
	case SIL_FAULT:
		new.ssi_addr = (long) kinfo->si_addr;
		break;
	case SIL_FAULT_TRAPNO:
		new.ssi_addr = (long) kinfo->si_addr;
		new.ssi_trapno = kinfo->si_trapno;
		break;
	case SIL_FAULT_MCEERR:
		new.ssi_addr = (long) kinfo->si_addr;
		new.ssi_addr_lsb = (short) kinfo->si_addr_lsb;
		break;
	case SIL_CHLD:
		new.ssi_pid    = kinfo->si_pid;
		new.ssi_uid    = kinfo->si_uid;
		new.ssi_status = kinfo->si_status;
		new.ssi_utime  = kinfo->si_utime;
		new.ssi_stime  = kinfo->si_stime;
		break;
	case SIL_RT:
		/*
		 * This case catches also the signals queued by sigqueue().
		 */
		new.ssi_pid = kinfo->si_pid;
		new.ssi_uid = kinfo->si_uid;
		new.ssi_ptr = (long) kinfo->si_ptr;
		new.ssi_int = kinfo->si_int;
		break;
	case SIL_SYS:
		new.ssi_call_addr = (long) kinfo->si_call_addr;
		new.ssi_syscall   = kinfo->si_syscall;
		new.ssi_arch      = kinfo->si_arch;
		break;
	}

	if (!copy_to_iter_full(&new, sizeof(struct signalfd_siginfo), to))
		return -EFAULT;

	return sizeof(struct signalfd_siginfo);
}

static ssize_t signalfd_dequeue(struct signalfd_ctx *ctx, kernel_siginfo_t *info,
				int nonblock)
{
	enum pid_type type;
	ssize_t ret;
	DECLARE_WAITQUEUE(wait, current);

	spin_lock_irq(&current->sighand->siglock);
	ret = dequeue_signal(&ctx->sigmask, info, &type);
	switch (ret) {
	case 0:
		if (!nonblock)
			break;
		ret = -EAGAIN;
		fallthrough;
	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(&ctx->sigmask, info, &type);
		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_iter(struct kiocb *iocb, struct iov_iter *to)
{
	struct file *file = iocb->ki_filp;
	struct signalfd_ctx *ctx = file->private_data;
	size_t count = iov_iter_count(to);
	ssize_t ret, total = 0;
	kernel_siginfo_t info;
	bool nonblock;

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

	nonblock = file->f_flags & O_NONBLOCK || iocb->ki_flags & IOCB_NOWAIT;
	do {
		ret = signalfd_dequeue(ctx, &info, nonblock);
		if (unlikely(ret <= 0))
			break;
		ret = signalfd_copyinfo(to, &info);
		if (ret < 0)
			break;
		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_iter	= signalfd_read_iter,
	.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) {
		struct file *file;

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

		ctx->sigmask = *mask;

		ufd = get_unused_fd_flags(flags & O_CLOEXEC);
		if (ufd < 0) {
			kfree(ctx);
			return ufd;
		}

		file = anon_inode_getfile_fmode("[signalfd]", &signalfd_fops,
					ctx, O_RDWR | (flags & O_NONBLOCK),
					FMODE_NOWAIT);
		if (IS_ERR(file)) {
			put_unused_fd(ufd);
			kfree(ctx);
			return PTR_ERR(file);
		}
		fd_install(ufd, file);
	} else {
		CLASS(fd, f)(ufd);
		if (fd_empty(f))
			return -EBADF;
		ctx = fd_file(f)->private_data;
		if (fd_file(f)->f_op != &signalfd_fops)
			return -EINVAL;
		spin_lock_irq(&current->sighand->siglock);
		ctx->sigmask = *mask;
		spin_unlock_irq(&current->sighand->siglock);

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

	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))
		return -EINVAL;
	if (copy_from_user(&mask, user_mask, sizeof(mask)))
		return -EFAULT;
	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))
		return -EINVAL;
	if (copy_from_user(&mask, user_mask, sizeof(mask)))
		return -EFAULT;
	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
	1	// SPDX-License-Identifier: GPL-2.0
	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.
	15	* Sat May 19, 2007: Davi E. M. Arnaut <davi@haxent.com.br>
	16	* Retrieve multiple signals with one read() call
	17	* Sun Jul 15, 2007: Davide Libenzi <davidel@xmailserver.org>
	18	* Attach to the sighand only during read() and poll().
	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>
	26	#include <linux/slab.h>
	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>
	32	#include <linux/syscalls.h>
	33	#include <linux/proc_fs.h>
	34	#include <linux/compat.h>
	35
	36	void signalfd_cleanup(struct sighand_struct *sighand)
	37	{
	38	wake_up_pollfree(&sighand->signalfd_wqh);
	39	}
	40
	41	struct signalfd_ctx {
	42	sigset_t sigmask;
	43	};
	44
	45	static int signalfd_release(struct inode inode, struct file file)
	46	{
	47	kfree(file->private_data);
	48	return 0;
	49	}
	50
	51	static __poll_t signalfd_poll(struct file file, poll_table wait)
	52	{
	53	struct signalfd_ctx *ctx = file->private_data;
	54	__poll_t events = 0;
	55
	56	poll_wait(file, &current->sighand->signalfd_wqh, wait);
	57
	58	spin_lock_irq(&current->sighand->siglock);
	59	if (next_signal(&current->pending, &ctx->sigmask) \|\|
	60	next_signal(&current->signal->shared_pending,
	61	&ctx->sigmask))
	62	events \|= EPOLLIN;
	63	spin_unlock_irq(&current->sighand->siglock);
	64
	65	return events;
	66	}
	67
	68	/*
	69	* Copied from copy_siginfo_to_user() in kernel/signal.c
	70	*/
	71	static int signalfd_copyinfo(struct iov_iter to, kernel_siginfo_t const kinfo)
	72	{
	73	struct signalfd_siginfo new;
	74
	75	BUILD_BUG_ON(sizeof(struct signalfd_siginfo) != 128);
	76
	77	/*
	78	* Unused members should be zero ...
	79	*/
	80	memset(&new, 0, sizeof(new));
	81
	82	/*
	83	* If you change siginfo_t structure, please be sure
	84	* this code is fixed accordingly.
	85	*/
	86	new.ssi_signo = kinfo->si_signo;
	87	new.ssi_errno = kinfo->si_errno;
	88	new.ssi_code = kinfo->si_code;
	89	switch (siginfo_layout(kinfo->si_signo, kinfo->si_code)) {
	90	case SIL_KILL:
	91	new.ssi_pid = kinfo->si_pid;
	92	new.ssi_uid = kinfo->si_uid;
	93	break;
	94	case SIL_TIMER:
	95	new.ssi_tid = kinfo->si_tid;
	96	new.ssi_overrun = kinfo->si_overrun;
	97	new.ssi_ptr = (long) kinfo->si_ptr;
	98	new.ssi_int = kinfo->si_int;
	99	break;
	100	case SIL_POLL:
	101	new.ssi_band = kinfo->si_band;
	102	new.ssi_fd = kinfo->si_fd;
	103	break;
	104	case SIL_FAULT_BNDERR:
	105	case SIL_FAULT_PKUERR:
	106	case SIL_FAULT_PERF_EVENT:
	107	/*
	108	* Fall through to the SIL_FAULT case. SIL_FAULT_BNDERR,
	109	* SIL_FAULT_PKUERR, and SIL_FAULT_PERF_EVENT are only
	110	* generated by faults that deliver them synchronously to
	111	* userspace. In case someone injects one of these signals
	112	* and signalfd catches it treat it as SIL_FAULT.
	113	*/
	114	case SIL_FAULT:
	115	new.ssi_addr = (long) kinfo->si_addr;
	116	break;
	117	case SIL_FAULT_TRAPNO:
	118	new.ssi_addr = (long) kinfo->si_addr;
	119	new.ssi_trapno = kinfo->si_trapno;
	120	break;
	121	case SIL_FAULT_MCEERR:
	122	new.ssi_addr = (long) kinfo->si_addr;
	123	new.ssi_addr_lsb = (short) kinfo->si_addr_lsb;
	124	break;
	125	case SIL_CHLD:
	126	new.ssi_pid = kinfo->si_pid;
	127	new.ssi_uid = kinfo->si_uid;
	128	new.ssi_status = kinfo->si_status;
	129	new.ssi_utime = kinfo->si_utime;
	130	new.ssi_stime = kinfo->si_stime;
	131	break;
	132	case SIL_RT:
	133	/*
	134	* This case catches also the signals queued by sigqueue().
	135	*/
	136	new.ssi_pid = kinfo->si_pid;
	137	new.ssi_uid = kinfo->si_uid;
	138	new.ssi_ptr = (long) kinfo->si_ptr;
	139	new.ssi_int = kinfo->si_int;
	140	break;
	141	case SIL_SYS:
	142	new.ssi_call_addr = (long) kinfo->si_call_addr;
	143	new.ssi_syscall = kinfo->si_syscall;
	144	new.ssi_arch = kinfo->si_arch;
	145	break;
	146	}
	147
	148	if (!copy_to_iter_full(&new, sizeof(struct signalfd_siginfo), to))
	149	return -EFAULT;
	150
	151	return sizeof(struct signalfd_siginfo);
	152	}
	153
	154	static ssize_t signalfd_dequeue(struct signalfd_ctx ctx, kernel_siginfo_t info,
	155	int nonblock)
	156	{
	157	enum pid_type type;
	158	ssize_t ret;
	159	DECLARE_WAITQUEUE(wait, current);
	160
	161	spin_lock_irq(&current->sighand->siglock);
	162	ret = dequeue_signal(&ctx->sigmask, info, &type);
	163	switch (ret) {
	164	case 0:
	165	if (!nonblock)
	166	break;
	167	ret = -EAGAIN;
	168	fallthrough;
	169	default:
	170	spin_unlock_irq(&current->sighand->siglock);
	171	return ret;
	172	}
	173
	174	add_wait_queue(&current->sighand->signalfd_wqh, &wait);
	175	for (;;) {
	176	set_current_state(TASK_INTERRUPTIBLE);
	177	ret = dequeue_signal(&ctx->sigmask, info, &type);
	178	if (ret != 0)
	179	break;
	180	if (signal_pending(current)) {
	181	ret = -ERESTARTSYS;
	182	break;
	183	}
	184	spin_unlock_irq(&current->sighand->siglock);
	185	schedule();
	186	spin_lock_irq(&current->sighand->siglock);
	187	}
	188	spin_unlock_irq(&current->sighand->siglock);
	189
	190	remove_wait_queue(&current->sighand->signalfd_wqh, &wait);
	191	__set_current_state(TASK_RUNNING);
	192
	193	return ret;
	194	}
	195
	196	/*
	197	* Returns a multiple of the size of a "struct signalfd_siginfo", or a negative
	198	* error code. The "count" parameter must be at least the size of a
	199	* "struct signalfd_siginfo".
	200	*/
	201	static ssize_t signalfd_read_iter(struct kiocb iocb, struct iov_iter to)
	202	{
	203	struct file *file = iocb->ki_filp;
	204	struct signalfd_ctx *ctx = file->private_data;
	205	size_t count = iov_iter_count(to);
	206	ssize_t ret, total = 0;
	207	kernel_siginfo_t info;
	208	bool nonblock;
	209
	210	count /= sizeof(struct signalfd_siginfo);
	211	if (!count)
	212	return -EINVAL;
	213
	214	nonblock = file->f_flags & O_NONBLOCK \|\| iocb->ki_flags & IOCB_NOWAIT;
	215	do {
	216	ret = signalfd_dequeue(ctx, &info, nonblock);
	217	if (unlikely(ret <= 0))
	218	break;
	219	ret = signalfd_copyinfo(to, &info);
	220	if (ret < 0)
	221	break;
	222	total += ret;
	223	nonblock = 1;
	224	} while (--count);
	225
	226	return total ? total: ret;
	227	}
	228
	229	#ifdef CONFIG_PROC_FS
	230	static void signalfd_show_fdinfo(struct seq_file m, struct file f)
	231	{
	232	struct signalfd_ctx *ctx = f->private_data;
	233	sigset_t sigmask;
	234
	235	sigmask = ctx->sigmask;
	236	signotset(&sigmask);
	237	render_sigset_t(m, "sigmask:\t", &sigmask);
	238	}
	239	#endif
	240
	241	static const struct file_operations signalfd_fops = {
	242	#ifdef CONFIG_PROC_FS
	243	.show_fdinfo = signalfd_show_fdinfo,
	244	#endif
	245	.release = signalfd_release,
	246	.poll = signalfd_poll,
	247	.read_iter = signalfd_read_iter,
	248	.llseek = noop_llseek,
	249	};
	250
	251	static int do_signalfd4(int ufd, sigset_t *mask, int flags)
	252	{
	253	struct signalfd_ctx *ctx;
	254
	255	/* Check the SFD_* constants for consistency. */
	256	BUILD_BUG_ON(SFD_CLOEXEC != O_CLOEXEC);
	257	BUILD_BUG_ON(SFD_NONBLOCK != O_NONBLOCK);
	258
	259	if (flags & ~(SFD_CLOEXEC \| SFD_NONBLOCK))
	260	return -EINVAL;
	261
	262	sigdelsetmask(mask, sigmask(SIGKILL) \| sigmask(SIGSTOP));
	263	signotset(mask);
	264
	265	if (ufd == -1) {
	266	struct file *file;
	267
	268	ctx = kmalloc(sizeof(*ctx), GFP_KERNEL);
	269	if (!ctx)
	270	return -ENOMEM;
	271
	272	ctx->sigmask = *mask;
	273
	274	ufd = get_unused_fd_flags(flags & O_CLOEXEC);
	275	if (ufd < 0) {
	276	kfree(ctx);
	277	return ufd;
	278	}
	279
	280	file = anon_inode_getfile_fmode("[signalfd]", &signalfd_fops,
	281	ctx, O_RDWR \| (flags & O_NONBLOCK),
	282	FMODE_NOWAIT);
	283	if (IS_ERR(file)) {
	284	put_unused_fd(ufd);
	285	kfree(ctx);
	286	return PTR_ERR(file);
	287	}
	288	fd_install(ufd, file);
	289	} else {
	290	CLASS(fd, f)(ufd);
	291	if (fd_empty(f))
	292	return -EBADF;
	293	ctx = fd_file(f)->private_data;
	294	if (fd_file(f)->f_op != &signalfd_fops)
	295	return -EINVAL;
	296	spin_lock_irq(&current->sighand->siglock);
	297	ctx->sigmask = *mask;
	298	spin_unlock_irq(&current->sighand->siglock);
	299
	300	wake_up(&current->sighand->signalfd_wqh);
	301	}
	302
	303	return ufd;
	304	}
	305
	306	SYSCALL_DEFINE4(signalfd4, int, ufd, sigset_t __user *, user_mask,
	307	size_t, sizemask, int, flags)
	308	{
	309	sigset_t mask;
	310
	311	if (sizemask != sizeof(sigset_t))
	312	return -EINVAL;
	313	if (copy_from_user(&mask, user_mask, sizeof(mask)))
	314	return -EFAULT;
	315	return do_signalfd4(ufd, &mask, flags);
	316	}
	317
	318	SYSCALL_DEFINE3(signalfd, int, ufd, sigset_t __user *, user_mask,
	319	size_t, sizemask)
	320	{
	321	sigset_t mask;
	322
	323	if (sizemask != sizeof(sigset_t))
	324	return -EINVAL;
	325	if (copy_from_user(&mask, user_mask, sizeof(mask)))
	326	return -EFAULT;
	327	return do_signalfd4(ufd, &mask, 0);
	328	}
	329
	330	#ifdef CONFIG_COMPAT
	331	static long do_compat_signalfd4(int ufd,
	332	const compat_sigset_t __user *user_mask,
	333	compat_size_t sigsetsize, int flags)
	334	{
	335	sigset_t mask;
	336
	337	if (sigsetsize != sizeof(compat_sigset_t))
	338	return -EINVAL;
	339	if (get_compat_sigset(&mask, user_mask))
	340	return -EFAULT;
	341	return do_signalfd4(ufd, &mask, flags);
	342	}
	343
	344	COMPAT_SYSCALL_DEFINE4(signalfd4, int, ufd,
	345	const compat_sigset_t __user *, user_mask,
	346	compat_size_t, sigsetsize,
	347	int, flags)
	348	{
	349	return do_compat_signalfd4(ufd, user_mask, sigsetsize, flags);
	350	}
	351
	352	COMPAT_SYSCALL_DEFINE3(signalfd, int, ufd,
	353	const compat_sigset_t __user *, user_mask,
	354	compat_size_t, sigsetsize)
	355	{
	356	return do_compat_signalfd4(ufd, user_mask, sigsetsize, 0);
	357	}
	358	#endif