[linux.git] / fs / signalfd.c

// SPDX-License-Identifier: GPL-2.0
/*
 *  fs/signalfd.c
 *
 *  Copyright (C) 2003  Linus Torvalds
 *
 *  Mon Mar 5, 2007: Davide Libenzi <[email protected]>
 *      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 <[email protected]>
 *      Retrieve multiple signals with one read() call
 *  Sun Jul 15, 2007: Davide Libenzi <[email protected]>
 *      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(current, &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(current, &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("[signalfd]", &signalfd_fops, ctx,
				       O_RDWR | (flags & O_NONBLOCK));
		if (IS_ERR(file)) {
			put_unused_fd(ufd);
			kfree(ctx);
			return PTR_ERR(file);
		}
		file->f_mode |= FMODE_NOWAIT;

		fd_install(ufd, file);
	} 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))
		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
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 <[email protected]>
	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 <[email protected]>
b3762bfc	16	* Retrieve multiple signals with one read() call
b8fceee1 DL	17	* Sun Jul 15, 2007: Davide Libenzi <[email protected]>
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)
d80e731e ON	37	{
9537bae0	38	wake_up_pollfree(&sighand->signalfd_wqh);
d80e731e ON	39	}
d80e731e ON	40
fba2afaa	41	struct signalfd_ctx {
fba2afaa	42	sigset_t sigmask;
fba2afaa DL	43	};
fba2afaa DL	44
fba2afaa DL	45	static int signalfd_release(struct inode inode, struct file file)
fba2afaa DL	46	{
b8fceee1	47	kfree(file->private_data);
fba2afaa DL	48	return 0;
	49	}
	50
076ccb76	51	static __poll_t signalfd_poll(struct file file, poll_table wait)
fba2afaa DL	52	{
fba2afaa DL	53	struct signalfd_ctx *ctx = file->private_data;
076ccb76	54	__poll_t events = 0;
fba2afaa	55
b8fceee1	56	poll_wait(file, &current->sighand->signalfd_wqh, wait);
fba2afaa	57
b8fceee1 DL	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))
a9a08845	62	events \|= EPOLLIN;
b8fceee1	63	spin_unlock_irq(&current->sighand->siglock);
fba2afaa DL	64
	65	return events;
	66	}
	67
	68	/*
	69	* Copied from copy_siginfo_to_user() in kernel/signal.c
	70	*/
fbe38120	71	static int signalfd_copyinfo(struct iov_iter to, kernel_siginfo_t const kinfo)
fba2afaa	72	{
5611f55e	73	struct signalfd_siginfo new;
fba2afaa DL	74
	75	BUILD_BUG_ON(sizeof(struct signalfd_siginfo) != 128);
	76
	77	/*
14e4a0f2	78	* Unused members should be zero ...
fba2afaa	79	*/
5611f55e	80	memset(&new, 0, sizeof(new));
fba2afaa DL	81
	82	/*
	83	* If you change siginfo_t structure, please be sure
	84	* this code is fixed accordingly.
	85	*/
5611f55e EB	86	new.ssi_signo = kinfo->si_signo;
	87	new.ssi_errno = kinfo->si_errno;
	88	new.ssi_code = kinfo->si_code;
cc731525 EB	89	switch (siginfo_layout(kinfo->si_signo, kinfo->si_code)) {
cc731525 EB	90	case SIL_KILL:
5611f55e EB	91	new.ssi_pid = kinfo->si_pid;
5611f55e EB	92	new.ssi_uid = kinfo->si_uid;
fba2afaa	93	break;
cc731525	94	case SIL_TIMER:
5611f55e EB	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;
fba2afaa	99	break;
cc731525	100	case SIL_POLL:
5611f55e EB	101	new.ssi_band = kinfo->si_band;
5611f55e EB	102	new.ssi_fd = kinfo->si_fd;
fba2afaa	103	break;
31931c93 EB	104	case SIL_FAULT_BNDERR:
31931c93 EB	105	case SIL_FAULT_PKUERR:
f4ac7302	106	case SIL_FAULT_PERF_EVENT:
31931c93	107	/*
922e3013	108	* Fall through to the SIL_FAULT case. SIL_FAULT_BNDERR,
f4ac7302	109	* SIL_FAULT_PKUERR, and SIL_FAULT_PERF_EVENT are only
922e3013 EB	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.
31931c93	113	*/
cc731525	114	case SIL_FAULT:
5611f55e	115	new.ssi_addr = (long) kinfo->si_addr;
9abcabe3 EB	116	break;
	117	case SIL_FAULT_TRAPNO:
	118	new.ssi_addr = (long) kinfo->si_addr;
5611f55e	119	new.ssi_trapno = kinfo->si_trapno;
31931c93 EB	120	break;
	121	case SIL_FAULT_MCEERR:
	122	new.ssi_addr = (long) kinfo->si_addr;
31931c93	123	new.ssi_addr_lsb = (short) kinfo->si_addr_lsb;
fba2afaa	124	break;
cc731525	125	case SIL_CHLD:
5611f55e EB	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;
fba2afaa	131	break;
cc731525	132	case SIL_RT:
0859ab59 DL	133	/*
	134	* This case catches also the signals queued by sigqueue().
	135	*/
5611f55e EB	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;
fba2afaa	140	break;
76b7f670 EB	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;
fba2afaa DL	146	}
fba2afaa DL	147
fbe38120	148	if (!copy_to_iter_full(&new, sizeof(struct signalfd_siginfo), to))
5611f55e EB	149	return -EFAULT;
5611f55e EB	150
fbe38120	151	return sizeof(struct signalfd_siginfo);
fba2afaa DL	152	}
fba2afaa DL	153
ae7795bc	154	static ssize_t signalfd_dequeue(struct signalfd_ctx ctx, kernel_siginfo_t info,
b3762bfc DA	155	int nonblock)
b3762bfc DA	156	{
5768d890	157	enum pid_type type;
b3762bfc	158	ssize_t ret;
b3762bfc DA	159	DECLARE_WAITQUEUE(wait, current);
b3762bfc DA	160
b8fceee1	161	spin_lock_irq(&current->sighand->siglock);
5768d890	162	ret = dequeue_signal(current, &ctx->sigmask, info, &type);
b3762bfc DA	163	switch (ret) {
	164	case 0:
	165	if (!nonblock)
	166	break;
	167	ret = -EAGAIN;
df561f66	168	fallthrough;
b3762bfc	169	default:
b8fceee1	170	spin_unlock_irq(&current->sighand->siglock);
b3762bfc DA	171	return ret;
	172	}
	173
b8fceee1	174	add_wait_queue(&current->sighand->signalfd_wqh, &wait);
b3762bfc DA	175	for (;;) {
b3762bfc DA	176	set_current_state(TASK_INTERRUPTIBLE);
5768d890	177	ret = dequeue_signal(current, &ctx->sigmask, info, &type);
b3762bfc DA	178	if (ret != 0)
	179	break;
	180	if (signal_pending(current)) {
	181	ret = -ERESTARTSYS;
	182	break;
	183	}
b8fceee1	184	spin_unlock_irq(&current->sighand->siglock);
b3762bfc	185	schedule();
b8fceee1	186	spin_lock_irq(&current->sighand->siglock);
b3762bfc	187	}
b8fceee1	188	spin_unlock_irq(&current->sighand->siglock);
b3762bfc	189
b8fceee1	190	remove_wait_queue(&current->sighand->signalfd_wqh, &wait);
b3762bfc DA	191	__set_current_state(TASK_RUNNING);
	192
	193	return ret;
	194	}
	195
fba2afaa	196	/*
b8fceee1 DL	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".
fba2afaa	200	*/
fbe38120	201	static ssize_t signalfd_read_iter(struct kiocb iocb, struct iov_iter to)
fba2afaa	202	{
fbe38120	203	struct file *file = iocb->ki_filp;
fba2afaa	204	struct signalfd_ctx *ctx = file->private_data;
fbe38120	205	size_t count = iov_iter_count(to);
b3762bfc	206	ssize_t ret, total = 0;
ae7795bc	207	kernel_siginfo_t info;
fbe38120	208	bool nonblock;
fba2afaa	209
b3762bfc DA	210	count /= sizeof(struct signalfd_siginfo);
b3762bfc DA	211	if (!count)
fba2afaa	212	return -EINVAL;
fba2afaa	213
fbe38120	214	nonblock = file->f_flags & O_NONBLOCK \|\| iocb->ki_flags & IOCB_NOWAIT;
b3762bfc DA	215	do {
	216	ret = signalfd_dequeue(ctx, &info, nonblock);
	217	if (unlikely(ret <= 0))
	218	break;
fbe38120	219	ret = signalfd_copyinfo(to, &info);
b3762bfc DA	220	if (ret < 0)
b3762bfc DA	221	break;
b3762bfc DA	222	total += ret;
	223	nonblock = 1;
	224	} while (--count);
	225
b8fceee1	226	return total ? total: ret;
fba2afaa DL	227	}
fba2afaa DL	228
138d22b5	229	#ifdef CONFIG_PROC_FS
a3816ab0	230	static void signalfd_show_fdinfo(struct seq_file m, struct file f)
138d22b5 CG	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);
138d22b5 CG	238	}
	239	#endif
	240
fba2afaa	241	static const struct file_operations signalfd_fops = {
138d22b5 CG	242	#ifdef CONFIG_PROC_FS
	243	.show_fdinfo = signalfd_show_fdinfo,
	244	#endif
fba2afaa DL	245	.release = signalfd_release,
fba2afaa DL	246	.poll = signalfd_poll,
fbe38120	247	.read_iter = signalfd_read_iter,
6038f373	248	.llseek = noop_llseek,
fba2afaa DL	249	};
fba2afaa DL	250
5ed0127f	251	static int do_signalfd4(int ufd, sigset_t *mask, int flags)
fba2afaa	252	{
fba2afaa	253	struct signalfd_ctx *ctx;
fba2afaa	254
e38b36f3 UD	255	/* Check the SFD_* constants for consistency. */
	256	BUILD_BUG_ON(SFD_CLOEXEC != O_CLOEXEC);
	257	BUILD_BUG_ON(SFD_NONBLOCK != O_NONBLOCK);
	258
5fb5e049	259	if (flags & ~(SFD_CLOEXEC \| SFD_NONBLOCK))
9deb27ba UD	260	return -EINVAL;
9deb27ba UD	261
5ed0127f AV	262	sigdelsetmask(mask, sigmask(SIGKILL) \| sigmask(SIGSTOP));
5ed0127f AV	263	signotset(mask);
fba2afaa DL	264
fba2afaa DL	265	if (ufd == -1) {
fbe38120 JA	266	struct file *file;
fbe38120 JA	267
fba2afaa DL	268	ctx = kmalloc(sizeof(*ctx), GFP_KERNEL);
	269	if (!ctx)
	270	return -ENOMEM;
	271
5ed0127f	272	ctx->sigmask = *mask;
fba2afaa	273
fbe38120 JA	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("[signalfd]", &signalfd_fops, ctx,
	281	O_RDWR \| (flags & O_NONBLOCK));
	282	if (IS_ERR(file)) {
	283	put_unused_fd(ufd);
	284	kfree(ctx);
f826bc9d	285	return PTR_ERR(file);
fbe38120 JA	286	}
	287	file->f_mode \|= FMODE_NOWAIT;
	288
fbe38120	289	fd_install(ufd, file);
fba2afaa	290	} else {
2903ff01 AV	291	struct fd f = fdget(ufd);
2903ff01 AV	292	if (!f.file)
fba2afaa	293	return -EBADF;
2903ff01 AV	294	ctx = f.file->private_data;
	295	if (f.file->f_op != &signalfd_fops) {
	296	fdput(f);
fba2afaa DL	297	return -EINVAL;
fba2afaa DL	298	}
b8fceee1	299	spin_lock_irq(&current->sighand->siglock);
5ed0127f	300	ctx->sigmask = *mask;
b8fceee1 DL	301	spin_unlock_irq(&current->sighand->siglock);
	302
	303	wake_up(&current->sighand->signalfd_wqh);
2903ff01	304	fdput(f);
fba2afaa DL	305	}
	306
	307	return ufd;
fba2afaa	308	}
9deb27ba	309
52fb6db0 DB	310	SYSCALL_DEFINE4(signalfd4, int, ufd, sigset_t __user *, user_mask,
	311	size_t, sizemask, int, flags)
	312	{
5ed0127f AV	313	sigset_t mask;
5ed0127f AV	314
a089e3fd	315	if (sizemask != sizeof(sigset_t))
5ed0127f	316	return -EINVAL;
a089e3fd HD	317	if (copy_from_user(&mask, user_mask, sizeof(mask)))
a089e3fd HD	318	return -EFAULT;
5ed0127f	319	return do_signalfd4(ufd, &mask, flags);
52fb6db0 DB	320	}
52fb6db0 DB	321
836f92ad HC	322	SYSCALL_DEFINE3(signalfd, int, ufd, sigset_t __user *, user_mask,
836f92ad HC	323	size_t, sizemask)
9deb27ba	324	{
5ed0127f AV	325	sigset_t mask;
5ed0127f AV	326
a089e3fd	327	if (sizemask != sizeof(sigset_t))
5ed0127f	328	return -EINVAL;
a089e3fd HD	329	if (copy_from_user(&mask, user_mask, sizeof(mask)))
a089e3fd HD	330	return -EFAULT;
5ed0127f	331	return do_signalfd4(ufd, &mask, 0);
9deb27ba	332	}
7d197ed4 AV	333
7d197ed4 AV	334	#ifdef CONFIG_COMPAT
570484bf	335	static long do_compat_signalfd4(int ufd,
5ed0127f	336	const compat_sigset_t __user *user_mask,
570484bf	337	compat_size_t sigsetsize, int flags)
7d197ed4	338	{
5ed0127f	339	sigset_t mask;
7d197ed4 AV	340
	341	if (sigsetsize != sizeof(compat_sigset_t))
	342	return -EINVAL;
5ed0127f	343	if (get_compat_sigset(&mask, user_mask))
7d197ed4	344	return -EFAULT;
5ed0127f	345	return do_signalfd4(ufd, &mask, flags);
7d197ed4 AV	346	}
7d197ed4 AV	347
570484bf	348	COMPAT_SYSCALL_DEFINE4(signalfd4, int, ufd,
5ed0127f	349	const compat_sigset_t __user *, user_mask,
570484bf DB	350	compat_size_t, sigsetsize,
	351	int, flags)
	352	{
5ed0127f	353	return do_compat_signalfd4(ufd, user_mask, sigsetsize, flags);
570484bf DB	354	}
570484bf DB	355
7d197ed4	356	COMPAT_SYSCALL_DEFINE3(signalfd, int, ufd,
5ed0127f	357	const compat_sigset_t __user *, user_mask,
7d197ed4 AV	358	compat_size_t, sigsetsize)
7d197ed4 AV	359	{
5ed0127f	360	return do_compat_signalfd4(ufd, user_mask, sigsetsize, 0);
7d197ed4 AV	361	}
7d197ed4 AV	362	#endif