linux/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)
{ … }

struct signalfd_ctx { … };

static int signalfd_release(struct inode *inode, struct file *file)
{ … }

static __poll_t signalfd_poll(struct file *file, poll_table *wait)
{ … }

/*
 * Copied from copy_siginfo_to_user() in kernel/signal.c
 */
static int signalfd_copyinfo(struct iov_iter *to, kernel_siginfo_t const *kinfo)
{ … }

static ssize_t signalfd_dequeue(struct signalfd_ctx *ctx, kernel_siginfo_t *info,
				int nonblock)
{ … }

/*
 * 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)
{ … }

#ifdef CONFIG_PROC_FS
static void signalfd_show_fdinfo(struct seq_file *m, struct file *f)
{ … }
#endif

static const struct file_operations signalfd_fops = …;

static int do_signalfd4(int ufd, sigset_t *mask, int flags)
{ … }

SYSCALL_DEFINE4(signalfd4, int, ufd, sigset_t __user *, user_mask,
		size_t, sizemask, int, flags)
{ … }

SYSCALL_DEFINE3(signalfd, int, ufd, sigset_t __user *, user_mask,
		size_t, sizemask)
{ … }

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

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

COMPAT_SYSCALL_DEFINE3(signalfd, int, ufd,
		     const compat_sigset_t __user *, user_mask,
		     compat_size_t, sigsetsize)
{ … }
#endif