Release 4.14 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, POLLHUP | POLLFREE);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Oleg Nesterov | 40 | 95.24% | 1 | 33.33% |
| Paul E. McKenney | 1 | 2.38% | 1 | 33.33% |
| Ingo Molnar | 1 | 2.38% | 1 | 33.33% |
| Total | 42 | 100.00% | 3 | 100.00% |
struct signalfd_ctx {
sigset_t sigmask;
};
static int signalfd_release(struct inode *inode, struct file *file)
{
kfree(file->private_data);
return 0;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Davide Libenzi | 26 | 100.00% | 2 | 100.00% |
| Total | 26 | 100.00% | 2 | 100.00% |
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, ¤t->sighand->signalfd_wqh, wait);
spin_lock_irq(¤t->sighand->siglock);
if (next_signal(¤t->pending, &ctx->sigmask) ||
next_signal(¤t->signal->shared_pending,
&ctx->sigmask))
events |= POLLIN;
spin_unlock_irq(¤t->sighand->siglock);
return events;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Davide Libenzi | 102 | 100.00% | 2 | 100.00% |
| Total | 102 | 100.00% | 2 | 100.00% |
/*
* 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_AR ||
kinfo->si_code == BUS_MCEERR_AO))
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);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Davide Libenzi | 393 | 84.33% | 3 | 37.50% |
| Hidetoshi Seto | 37 | 7.94% | 1 | 12.50% |
| Nathan T. Lynch | 14 | 3.00% | 1 | 12.50% |
| Eric W. Biedermann | 13 | 2.79% | 1 | 12.50% |
| Amanieu d'Antras | 8 | 1.72% | 1 | 12.50% |
| Robert P. J. Day | 1 | 0.21% | 1 | 12.50% |
| Total | 466 | 100.00% | 8 | 100.00% |
static ssize_t signalfd_dequeue(struct signalfd_ctx *ctx, siginfo_t *info,
int nonblock)
{
ssize_t ret;
DECLARE_WAITQUEUE(wait, current);
spin_lock_irq(¤t->sighand->siglock);
ret = dequeue_signal(current, &ctx->sigmask, info);
switch (ret) {
case 0:
if (!nonblock)
break;
ret = -EAGAIN;
default:
spin_unlock_irq(¤t->sighand->siglock);
return ret;
}
add_wait_queue(¤t->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(¤t->sighand->siglock);
schedule();
spin_lock_irq(¤t->sighand->siglock);
}
spin_unlock_irq(¤t->sighand->siglock);
remove_wait_queue(¤t->sighand->signalfd_wqh, &wait);
__set_current_state(TASK_RUNNING);
return ret;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Davide Libenzi | 162 | 80.60% | 2 | 66.67% |
| Davi Arnaut | 39 | 19.40% | 1 | 33.33% |
| Total | 201 | 100.00% | 3 | 100.00% |
/*
* 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;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Davi Arnaut | 127 | 84.67% | 1 | 50.00% |
| Davide Libenzi | 23 | 15.33% | 1 | 50.00% |
| Total | 150 | 100.00% | 2 | 100.00% |
#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);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Cyrill V. Gorcunov | 49 | 98.00% | 1 | 50.00% |
| Joe Perches | 1 | 2.00% | 1 | 50.00% |
| Total | 50 | 100.00% | 2 | 100.00% |
#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(¤t->sighand->siglock);
ctx->sigmask = sigmask;
spin_unlock_irq(¤t->sighand->siglock);
wake_up(¤t->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
Overall Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Davide Libenzi | 961 | 60.25% | 4 | 14.29% |
| Al Viro | 181 | 11.35% | 3 | 10.71% |
| Davi Arnaut | 166 | 10.41% | 1 | 3.57% |
| Cyrill V. Gorcunov | 67 | 4.20% | 1 | 3.57% |
| Ulrich Drepper | 52 | 3.26% | 4 | 14.29% |
| Oleg Nesterov | 40 | 2.51% | 1 | 3.57% |
| Hidetoshi Seto | 37 | 2.32% | 1 | 3.57% |
| Heiko Carstens | 36 | 2.26% | 1 | 3.57% |
| Nathan T. Lynch | 14 | 0.88% | 1 | 3.57% |
| Eric W. Biedermann | 13 | 0.82% | 1 | 3.57% |
| Amanieu d'Antras | 8 | 0.50% | 1 | 3.57% |
| Arnd Bergmann | 5 | 0.31% | 1 | 3.57% |
| Roland Dreier | 4 | 0.25% | 1 | 3.57% |
| Adrian Bunk | 3 | 0.19% | 1 | 3.57% |
| Tejun Heo | 3 | 0.19% | 1 | 3.57% |
| Ingo Molnar | 1 | 0.06% | 1 | 3.57% |
| Paul E. McKenney | 1 | 0.06% | 1 | 3.57% |
| Greg Kroah-Hartman | 1 | 0.06% | 1 | 3.57% |
| Joe Perches | 1 | 0.06% | 1 | 3.57% |
| Robert P. J. Day | 1 | 0.06% | 1 | 3.57% |
| Total | 1595 | 100.00% | 28 | 100.00% |
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