[mirror_ubuntu-bionic-kernel.git] / fs / signalfd.c

/*
 *  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_DESTROY_BY_RCU, we can safely return.
	 */
	if (likely(!waitqueue_active(wqh)))
		return;

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

struct signalfd_ctx {
	sigset_t sigmask;
};

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

static unsigned int signalfd_poll(struct file *file, poll_table *wait)
{
	struct signalfd_ctx *ctx = file->private_data;
	unsigned int 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 |= POLLIN;
	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((short) kinfo->si_code, &uinfo->ssi_code);
	switch (kinfo->si_code & __SI_MASK) {
	case __SI_KILL:
		err |= __put_user(kinfo->si_pid, &uinfo->ssi_pid);
		err |= __put_user(kinfo->si_uid, &uinfo->ssi_uid);
		break;
	case __SI_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 __SI_POLL:
		err |= __put_user(kinfo->si_band, &uinfo->ssi_band);
		err |= __put_user(kinfo->si_fd, &uinfo->ssi_fd);
		break;
	case __SI_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_code == BUS_MCEERR_AR ||
		    kinfo->si_code == BUS_MCEERR_AO)
			err |= __put_user((short) kinfo->si_addr_lsb,
					  &uinfo->ssi_addr_lsb);
#endif
		break;
	case __SI_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 __SI_RT: /* This is not generated by the kernel as of now. */
	case __SI_MESGQ: /* But this is */
		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;
	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,
};

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

	if (sizemask != sizeof(sigset_t) ||
	    copy_from_user(&sigmask, user_mask, sizeof(sigmask)))
		return -EINVAL;
	sigdelsetmask(&sigmask, sigmask(SIGKILL) | sigmask(SIGSTOP));
	signotset(&sigmask);

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

		ctx->sigmask = sigmask;

		/*
		 * 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 = sigmask;
		spin_unlock_irq(&current->sighand->siglock);

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

	return ufd;
}

SYSCALL_DEFINE3(signalfd, int, ufd, sigset_t __user *, user_mask,
		size_t, sizemask)
{
	return sys_signalfd4(ufd, user_mask, sizemask, 0);
}

#ifdef CONFIG_COMPAT
COMPAT_SYSCALL_DEFINE4(signalfd4, int, ufd,
		     const compat_sigset_t __user *,sigmask,
		     compat_size_t, sigsetsize,
		     int, flags)
{
	compat_sigset_t ss32;
	sigset_t tmp;
	sigset_t __user *ksigmask;

	if (sigsetsize != sizeof(compat_sigset_t))
		return -EINVAL;
	if (copy_from_user(&ss32, sigmask, sizeof(ss32)))
		return -EFAULT;
	sigset_from_compat(&tmp, &ss32);
	ksigmask = compat_alloc_user_space(sizeof(sigset_t));
	if (copy_to_user(ksigmask, &tmp, sizeof(sigset_t)))
		return -EFAULT;

	return sys_signalfd4(ufd, ksigmask, sizeof(sigset_t), flags);
}

COMPAT_SYSCALL_DEFINE3(signalfd, int, ufd,
		     const compat_sigset_t __user *,sigmask,
		     compat_size_t, sigsetsize)
{
	return compat_sys_signalfd4(ufd, sigmask, sigsetsize, 0);
}
#endif
Commit	Line	Data
fba2afaa DL	1	/*
	2	* fs/signalfd.c
	3	*
	4	* Copyright (C) 2003 Linus Torvalds
	5	*
	6	* Mon Mar 5, 2007: Davide Libenzi <davidel@xmailserver.org>
	7	* Changed ->read() to return a siginfo strcture instead of signal number.
	8	* Fixed locking in ->poll().
	9	* Added sighand-detach notification.
	10	* Added fd re-use in sys_signalfd() syscall.
	11	* Now using anonymous inode source.
	12	* Thanks to Oleg Nesterov for useful code review and suggestions.
	13	* More comments and suggestions from Arnd Bergmann.
b8fceee1	14	* Sat May 19, 2007: Davi E. M. Arnaut <davi@haxent.com.br>
b3762bfc	15	* Retrieve multiple signals with one read() call
b8fceee1 DL	16	* Sun Jul 15, 2007: Davide Libenzi <davidel@xmailserver.org>
b8fceee1 DL	17	* Attach to the sighand only during read() and poll().
fba2afaa DL	18	*/
	19
	20	#include <linux/file.h>
	21	#include <linux/poll.h>
	22	#include <linux/init.h>
	23	#include <linux/fs.h>
	24	#include <linux/sched.h>
5a0e3ad6	25	#include <linux/slab.h>
fba2afaa DL	26	#include <linux/kernel.h>
	27	#include <linux/signal.h>
	28	#include <linux/list.h>
	29	#include <linux/anon_inodes.h>
	30	#include <linux/signalfd.h>
7ec37dfd	31	#include <linux/syscalls.h>
138d22b5	32	#include <linux/proc_fs.h>
7d197ed4	33	#include <linux/compat.h>
fba2afaa	34
d80e731e ON	35	void signalfd_cleanup(struct sighand_struct *sighand)
	36	{
	37	wait_queue_head_t *wqh = &sighand->signalfd_wqh;
971316f0 ON	38	/*
	39	* The lockless check can race with remove_wait_queue() in progress,
	40	* but in this case its caller should run under rcu_read_lock() and
	41	* sighand_cachep is SLAB_DESTROY_BY_RCU, we can safely return.
	42	*/
d80e731e ON	43	if (likely(!waitqueue_active(wqh)))
	44	return;
	45
	46	/* wait_queue_t->func(POLLFREE) should do remove_wait_queue() */
	47	wake_up_poll(wqh, POLLHUP \| POLLFREE);
	48	}
	49
fba2afaa	50	struct signalfd_ctx {
fba2afaa	51	sigset_t sigmask;
fba2afaa DL	52	};
fba2afaa DL	53
fba2afaa DL	54	static int signalfd_release(struct inode inode, struct file file)
fba2afaa DL	55	{
b8fceee1	56	kfree(file->private_data);
fba2afaa DL	57	return 0;
	58	}
	59
	60	static unsigned int signalfd_poll(struct file file, poll_table wait)
	61	{
	62	struct signalfd_ctx *ctx = file->private_data;
	63	unsigned int events = 0;
fba2afaa	64
b8fceee1	65	poll_wait(file, &current->sighand->signalfd_wqh, wait);
fba2afaa	66
b8fceee1 DL	67	spin_lock_irq(&current->sighand->siglock);
	68	if (next_signal(&current->pending, &ctx->sigmask) \|\|
	69	next_signal(&current->signal->shared_pending,
	70	&ctx->sigmask))
fba2afaa	71	events \|= POLLIN;
b8fceee1	72	spin_unlock_irq(&current->sighand->siglock);
fba2afaa DL	73
	74	return events;
	75	}
	76
	77	/*
	78	* Copied from copy_siginfo_to_user() in kernel/signal.c
	79	*/
	80	static int signalfd_copyinfo(struct signalfd_siginfo __user *uinfo,
	81	siginfo_t const *kinfo)
	82	{
	83	long err;
	84
	85	BUILD_BUG_ON(sizeof(struct signalfd_siginfo) != 128);
	86
	87	/*
14e4a0f2	88	* Unused members should be zero ...
fba2afaa DL	89	*/
	90	err = __clear_user(uinfo, sizeof(*uinfo));
	91
	92	/*
	93	* If you change siginfo_t structure, please be sure
	94	* this code is fixed accordingly.
	95	*/
96358de6 DL	96	err \|= __put_user(kinfo->si_signo, &uinfo->ssi_signo);
	97	err \|= __put_user(kinfo->si_errno, &uinfo->ssi_errno);
	98	err \|= __put_user((short) kinfo->si_code, &uinfo->ssi_code);
fba2afaa DL	99	switch (kinfo->si_code & __SI_MASK) {
fba2afaa DL	100	case __SI_KILL:
96358de6 DL	101	err \|= __put_user(kinfo->si_pid, &uinfo->ssi_pid);
96358de6 DL	102	err \|= __put_user(kinfo->si_uid, &uinfo->ssi_uid);
fba2afaa DL	103	break;
fba2afaa DL	104	case __SI_TIMER:
96358de6 DL	105	err \|= __put_user(kinfo->si_tid, &uinfo->ssi_tid);
	106	err \|= __put_user(kinfo->si_overrun, &uinfo->ssi_overrun);
	107	err \|= __put_user((long) kinfo->si_ptr, &uinfo->ssi_ptr);
a2a20c41	108	err \|= __put_user(kinfo->si_int, &uinfo->ssi_int);
fba2afaa DL	109	break;
fba2afaa DL	110	case __SI_POLL:
96358de6 DL	111	err \|= __put_user(kinfo->si_band, &uinfo->ssi_band);
96358de6 DL	112	err \|= __put_user(kinfo->si_fd, &uinfo->ssi_fd);
fba2afaa DL	113	break;
fba2afaa DL	114	case __SI_FAULT:
96358de6	115	err \|= __put_user((long) kinfo->si_addr, &uinfo->ssi_addr);
fba2afaa	116	#ifdef __ARCH_SI_TRAPNO
96358de6	117	err \|= __put_user(kinfo->si_trapno, &uinfo->ssi_trapno);
b8aeec34 HS	118	#endif
	119	#ifdef BUS_MCEERR_AO
	120	/*
	121	* Other callers might not initialize the si_lsb field,
	122	* so check explicitly for the right codes here.
	123	*/
	124	if (kinfo->si_code == BUS_MCEERR_AR \|\|
	125	kinfo->si_code == BUS_MCEERR_AO)
	126	err \|= __put_user((short) kinfo->si_addr_lsb,
	127	&uinfo->ssi_addr_lsb);
fba2afaa DL	128	#endif
	129	break;
	130	case __SI_CHLD:
96358de6 DL	131	err \|= __put_user(kinfo->si_pid, &uinfo->ssi_pid);
	132	err \|= __put_user(kinfo->si_uid, &uinfo->ssi_uid);
	133	err \|= __put_user(kinfo->si_status, &uinfo->ssi_status);
	134	err \|= __put_user(kinfo->si_utime, &uinfo->ssi_utime);
	135	err \|= __put_user(kinfo->si_stime, &uinfo->ssi_stime);
fba2afaa DL	136	break;
	137	case __SI_RT: /* This is not generated by the kernel as of now. */
	138	case __SI_MESGQ: /* But this is */
96358de6 DL	139	err \|= __put_user(kinfo->si_pid, &uinfo->ssi_pid);
	140	err \|= __put_user(kinfo->si_uid, &uinfo->ssi_uid);
	141	err \|= __put_user((long) kinfo->si_ptr, &uinfo->ssi_ptr);
a2a20c41	142	err \|= __put_user(kinfo->si_int, &uinfo->ssi_int);
fba2afaa	143	break;
0859ab59 DL	144	default:
	145	/*
	146	* This case catches also the signals queued by sigqueue().
	147	*/
96358de6 DL	148	err \|= __put_user(kinfo->si_pid, &uinfo->ssi_pid);
96358de6 DL	149	err \|= __put_user(kinfo->si_uid, &uinfo->ssi_uid);
0859ab59 DL	150	err \|= __put_user((long) kinfo->si_ptr, &uinfo->ssi_ptr);
0859ab59 DL	151	err \|= __put_user(kinfo->si_int, &uinfo->ssi_int);
fba2afaa DL	152	break;
	153	}
	154
	155	return err ? -EFAULT: sizeof(*uinfo);
	156	}
	157
b3762bfc DA	158	static ssize_t signalfd_dequeue(struct signalfd_ctx ctx, siginfo_t info,
	159	int nonblock)
	160	{
	161	ssize_t ret;
b3762bfc DA	162	DECLARE_WAITQUEUE(wait, current);
b3762bfc DA	163
b8fceee1 DL	164	spin_lock_irq(&current->sighand->siglock);
b8fceee1 DL	165	ret = dequeue_signal(current, &ctx->sigmask, info);
b3762bfc DA	166	switch (ret) {
	167	case 0:
	168	if (!nonblock)
	169	break;
	170	ret = -EAGAIN;
	171	default:
b8fceee1	172	spin_unlock_irq(&current->sighand->siglock);
b3762bfc DA	173	return ret;
	174	}
	175
b8fceee1	176	add_wait_queue(&current->sighand->signalfd_wqh, &wait);
b3762bfc DA	177	for (;;) {
b3762bfc DA	178	set_current_state(TASK_INTERRUPTIBLE);
b8fceee1	179	ret = dequeue_signal(current, &ctx->sigmask, info);
b3762bfc DA	180	if (ret != 0)
	181	break;
	182	if (signal_pending(current)) {
	183	ret = -ERESTARTSYS;
	184	break;
	185	}
b8fceee1	186	spin_unlock_irq(&current->sighand->siglock);
b3762bfc	187	schedule();
b8fceee1	188	spin_lock_irq(&current->sighand->siglock);
b3762bfc	189	}
b8fceee1	190	spin_unlock_irq(&current->sighand->siglock);
b3762bfc	191
b8fceee1	192	remove_wait_queue(&current->sighand->signalfd_wqh, &wait);
b3762bfc DA	193	__set_current_state(TASK_RUNNING);
	194
	195	return ret;
	196	}
	197
fba2afaa	198	/*
b8fceee1 DL	199	* Returns a multiple of the size of a "struct signalfd_siginfo", or a negative
	200	* error code. The "count" parameter must be at least the size of a
	201	* "struct signalfd_siginfo".
fba2afaa DL	202	*/
	203	static ssize_t signalfd_read(struct file file, char __user buf, size_t count,
	204	loff_t *ppos)
	205	{
	206	struct signalfd_ctx *ctx = file->private_data;
b3762bfc DA	207	struct signalfd_siginfo __user *siginfo;
	208	int nonblock = file->f_flags & O_NONBLOCK;
	209	ssize_t ret, total = 0;
fba2afaa	210	siginfo_t info;
fba2afaa	211
b3762bfc DA	212	count /= sizeof(struct signalfd_siginfo);
b3762bfc DA	213	if (!count)
fba2afaa	214	return -EINVAL;
fba2afaa	215
b3762bfc	216	siginfo = (struct signalfd_siginfo __user *) buf;
b3762bfc DA	217	do {
	218	ret = signalfd_dequeue(ctx, &info, nonblock);
	219	if (unlikely(ret <= 0))
	220	break;
	221	ret = signalfd_copyinfo(siginfo, &info);
	222	if (ret < 0)
	223	break;
	224	siginfo++;
	225	total += ret;
	226	nonblock = 1;
	227	} while (--count);
	228
b8fceee1	229	return total ? total: ret;
fba2afaa DL	230	}
fba2afaa DL	231
138d22b5	232	#ifdef CONFIG_PROC_FS
a3816ab0	233	static void signalfd_show_fdinfo(struct seq_file m, struct file f)
138d22b5 CG	234	{
	235	struct signalfd_ctx *ctx = f->private_data;
	236	sigset_t sigmask;
	237
	238	sigmask = ctx->sigmask;
	239	signotset(&sigmask);
	240	render_sigset_t(m, "sigmask:\t", &sigmask);
138d22b5 CG	241	}
	242	#endif
	243
fba2afaa	244	static const struct file_operations signalfd_fops = {
138d22b5 CG	245	#ifdef CONFIG_PROC_FS
	246	.show_fdinfo = signalfd_show_fdinfo,
	247	#endif
fba2afaa DL	248	.release = signalfd_release,
	249	.poll = signalfd_poll,
	250	.read = signalfd_read,
6038f373	251	.llseek = noop_llseek,
fba2afaa DL	252	};
fba2afaa DL	253
836f92ad HC	254	SYSCALL_DEFINE4(signalfd4, int, ufd, sigset_t __user *, user_mask,
836f92ad HC	255	size_t, sizemask, int, flags)
fba2afaa	256	{
fba2afaa DL	257	sigset_t sigmask;
fba2afaa DL	258	struct signalfd_ctx *ctx;
fba2afaa	259
e38b36f3 UD	260	/* Check the SFD_* constants for consistency. */
	261	BUILD_BUG_ON(SFD_CLOEXEC != O_CLOEXEC);
	262	BUILD_BUG_ON(SFD_NONBLOCK != O_NONBLOCK);
	263
5fb5e049	264	if (flags & ~(SFD_CLOEXEC \| SFD_NONBLOCK))
9deb27ba UD	265	return -EINVAL;
9deb27ba UD	266
fba2afaa DL	267	if (sizemask != sizeof(sigset_t) \|\|
fba2afaa DL	268	copy_from_user(&sigmask, user_mask, sizeof(sigmask)))
f50cadaa	269	return -EINVAL;
fba2afaa DL	270	sigdelsetmask(&sigmask, sigmask(SIGKILL) \| sigmask(SIGSTOP));
	271	signotset(&sigmask);
	272
	273	if (ufd == -1) {
	274	ctx = kmalloc(sizeof(*ctx), GFP_KERNEL);
	275	if (!ctx)
	276	return -ENOMEM;
	277
fba2afaa	278	ctx->sigmask = sigmask;
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 DL	297	spin_lock_irq(&current->sighand->siglock);
	298	ctx->sigmask = sigmask;
	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
836f92ad HC	308	SYSCALL_DEFINE3(signalfd, int, ufd, sigset_t __user *, user_mask,
836f92ad HC	309	size_t, sizemask)
9deb27ba UD	310	{
	311	return sys_signalfd4(ufd, user_mask, sizemask, 0);
	312	}
7d197ed4 AV	313
	314	#ifdef CONFIG_COMPAT
	315	COMPAT_SYSCALL_DEFINE4(signalfd4, int, ufd,
	316	const compat_sigset_t __user *,sigmask,
	317	compat_size_t, sigsetsize,
	318	int, flags)
	319	{
	320	compat_sigset_t ss32;
	321	sigset_t tmp;
	322	sigset_t __user *ksigmask;
	323
	324	if (sigsetsize != sizeof(compat_sigset_t))
	325	return -EINVAL;
	326	if (copy_from_user(&ss32, sigmask, sizeof(ss32)))
	327	return -EFAULT;
	328	sigset_from_compat(&tmp, &ss32);
	329	ksigmask = compat_alloc_user_space(sizeof(sigset_t));
	330	if (copy_to_user(ksigmask, &tmp, sizeof(sigset_t)))
	331	return -EFAULT;
	332
	333	return sys_signalfd4(ufd, ksigmask, sizeof(sigset_t), flags);
	334	}
	335
	336	COMPAT_SYSCALL_DEFINE3(signalfd, int, ufd,
	337	const compat_sigset_t __user *,sigmask,
	338	compat_size_t, sigsetsize)
	339	{
	340	return compat_sys_signalfd4(ufd, sigmask, sigsetsize, 0);
	341	}
	342	#endif