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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-10-30 08:02:30 +00:00
2585402c57
[ Upstream commit a089e3fd5a
]
The kernel signalfd4() syscall returns different error codes when called
either in compat or native mode. This behaviour makes correct emulation
in qemu and testing programs like LTP more complicated.
Fix the code to always return -in both modes- EFAULT for unaccessible user
memory, and EINVAL when called with an invalid signal mask.
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Laurent Vivier <laurent@vivier.eu>
Link: http://lkml.kernel.org/r/20200530100707.GA10159@ls3530.fritz.box
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
364 lines
9 KiB
C
364 lines
9 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* fs/signalfd.c
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*
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* Copyright (C) 2003 Linus Torvalds
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*
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* Mon Mar 5, 2007: Davide Libenzi <davidel@xmailserver.org>
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* Changed ->read() to return a siginfo strcture instead of signal number.
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* Fixed locking in ->poll().
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* Added sighand-detach notification.
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* Added fd re-use in sys_signalfd() syscall.
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* Now using anonymous inode source.
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* Thanks to Oleg Nesterov for useful code review and suggestions.
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* More comments and suggestions from Arnd Bergmann.
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* Sat May 19, 2007: Davi E. M. Arnaut <davi@haxent.com.br>
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* Retrieve multiple signals with one read() call
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* Sun Jul 15, 2007: Davide Libenzi <davidel@xmailserver.org>
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* Attach to the sighand only during read() and poll().
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*/
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#include <linux/file.h>
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#include <linux/poll.h>
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#include <linux/init.h>
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#include <linux/fs.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/kernel.h>
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#include <linux/signal.h>
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#include <linux/list.h>
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#include <linux/anon_inodes.h>
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#include <linux/signalfd.h>
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#include <linux/syscalls.h>
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#include <linux/proc_fs.h>
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#include <linux/compat.h>
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void signalfd_cleanup(struct sighand_struct *sighand)
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{
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wait_queue_head_t *wqh = &sighand->signalfd_wqh;
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/*
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* The lockless check can race with remove_wait_queue() in progress,
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* but in this case its caller should run under rcu_read_lock() and
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* sighand_cachep is SLAB_TYPESAFE_BY_RCU, we can safely return.
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*/
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if (likely(!waitqueue_active(wqh)))
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return;
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/* wait_queue_entry_t->func(POLLFREE) should do remove_wait_queue() */
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wake_up_poll(wqh, EPOLLHUP | POLLFREE);
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}
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struct signalfd_ctx {
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sigset_t sigmask;
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};
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static int signalfd_release(struct inode *inode, struct file *file)
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{
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kfree(file->private_data);
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return 0;
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}
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static __poll_t signalfd_poll(struct file *file, poll_table *wait)
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{
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struct signalfd_ctx *ctx = file->private_data;
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__poll_t events = 0;
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poll_wait(file, ¤t->sighand->signalfd_wqh, wait);
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spin_lock_irq(¤t->sighand->siglock);
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if (next_signal(¤t->pending, &ctx->sigmask) ||
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next_signal(¤t->signal->shared_pending,
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&ctx->sigmask))
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events |= EPOLLIN;
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spin_unlock_irq(¤t->sighand->siglock);
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return events;
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}
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/*
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* Copied from copy_siginfo_to_user() in kernel/signal.c
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*/
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static int signalfd_copyinfo(struct signalfd_siginfo __user *uinfo,
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kernel_siginfo_t const *kinfo)
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{
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struct signalfd_siginfo new;
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BUILD_BUG_ON(sizeof(struct signalfd_siginfo) != 128);
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/*
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* Unused members should be zero ...
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*/
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memset(&new, 0, sizeof(new));
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/*
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* If you change siginfo_t structure, please be sure
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* this code is fixed accordingly.
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*/
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new.ssi_signo = kinfo->si_signo;
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new.ssi_errno = kinfo->si_errno;
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new.ssi_code = kinfo->si_code;
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switch (siginfo_layout(kinfo->si_signo, kinfo->si_code)) {
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case SIL_KILL:
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new.ssi_pid = kinfo->si_pid;
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new.ssi_uid = kinfo->si_uid;
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break;
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case SIL_TIMER:
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new.ssi_tid = kinfo->si_tid;
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new.ssi_overrun = kinfo->si_overrun;
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new.ssi_ptr = (long) kinfo->si_ptr;
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new.ssi_int = kinfo->si_int;
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break;
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case SIL_POLL:
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new.ssi_band = kinfo->si_band;
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new.ssi_fd = kinfo->si_fd;
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break;
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case SIL_FAULT_BNDERR:
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case SIL_FAULT_PKUERR:
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/*
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* Fall through to the SIL_FAULT case. Both SIL_FAULT_BNDERR
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* and SIL_FAULT_PKUERR are only generated by faults that
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* deliver them synchronously to userspace. In case someone
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* injects one of these signals and signalfd catches it treat
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* it as SIL_FAULT.
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*/
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case SIL_FAULT:
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new.ssi_addr = (long) kinfo->si_addr;
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#ifdef __ARCH_SI_TRAPNO
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new.ssi_trapno = kinfo->si_trapno;
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#endif
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break;
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case SIL_FAULT_MCEERR:
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new.ssi_addr = (long) kinfo->si_addr;
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#ifdef __ARCH_SI_TRAPNO
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new.ssi_trapno = kinfo->si_trapno;
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#endif
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new.ssi_addr_lsb = (short) kinfo->si_addr_lsb;
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break;
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case SIL_CHLD:
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new.ssi_pid = kinfo->si_pid;
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new.ssi_uid = kinfo->si_uid;
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new.ssi_status = kinfo->si_status;
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new.ssi_utime = kinfo->si_utime;
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new.ssi_stime = kinfo->si_stime;
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break;
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case SIL_RT:
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/*
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* This case catches also the signals queued by sigqueue().
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*/
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new.ssi_pid = kinfo->si_pid;
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new.ssi_uid = kinfo->si_uid;
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new.ssi_ptr = (long) kinfo->si_ptr;
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new.ssi_int = kinfo->si_int;
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break;
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case SIL_SYS:
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new.ssi_call_addr = (long) kinfo->si_call_addr;
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new.ssi_syscall = kinfo->si_syscall;
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new.ssi_arch = kinfo->si_arch;
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break;
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}
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if (copy_to_user(uinfo, &new, sizeof(struct signalfd_siginfo)))
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return -EFAULT;
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return sizeof(*uinfo);
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}
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static ssize_t signalfd_dequeue(struct signalfd_ctx *ctx, kernel_siginfo_t *info,
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int nonblock)
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{
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ssize_t ret;
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DECLARE_WAITQUEUE(wait, current);
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spin_lock_irq(¤t->sighand->siglock);
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ret = dequeue_signal(current, &ctx->sigmask, info);
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switch (ret) {
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case 0:
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if (!nonblock)
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break;
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ret = -EAGAIN;
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/* fall through */
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default:
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spin_unlock_irq(¤t->sighand->siglock);
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return ret;
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}
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add_wait_queue(¤t->sighand->signalfd_wqh, &wait);
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for (;;) {
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set_current_state(TASK_INTERRUPTIBLE);
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ret = dequeue_signal(current, &ctx->sigmask, info);
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if (ret != 0)
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break;
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if (signal_pending(current)) {
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ret = -ERESTARTSYS;
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break;
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}
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spin_unlock_irq(¤t->sighand->siglock);
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schedule();
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spin_lock_irq(¤t->sighand->siglock);
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}
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spin_unlock_irq(¤t->sighand->siglock);
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remove_wait_queue(¤t->sighand->signalfd_wqh, &wait);
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__set_current_state(TASK_RUNNING);
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return ret;
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}
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/*
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* Returns a multiple of the size of a "struct signalfd_siginfo", or a negative
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* error code. The "count" parameter must be at least the size of a
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* "struct signalfd_siginfo".
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*/
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static ssize_t signalfd_read(struct file *file, char __user *buf, size_t count,
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loff_t *ppos)
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{
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struct signalfd_ctx *ctx = file->private_data;
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struct signalfd_siginfo __user *siginfo;
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int nonblock = file->f_flags & O_NONBLOCK;
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ssize_t ret, total = 0;
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kernel_siginfo_t info;
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count /= sizeof(struct signalfd_siginfo);
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if (!count)
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return -EINVAL;
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siginfo = (struct signalfd_siginfo __user *) buf;
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do {
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ret = signalfd_dequeue(ctx, &info, nonblock);
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if (unlikely(ret <= 0))
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break;
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ret = signalfd_copyinfo(siginfo, &info);
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if (ret < 0)
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break;
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siginfo++;
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total += ret;
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nonblock = 1;
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} while (--count);
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return total ? total: ret;
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}
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#ifdef CONFIG_PROC_FS
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static void signalfd_show_fdinfo(struct seq_file *m, struct file *f)
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{
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struct signalfd_ctx *ctx = f->private_data;
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sigset_t sigmask;
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sigmask = ctx->sigmask;
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signotset(&sigmask);
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render_sigset_t(m, "sigmask:\t", &sigmask);
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}
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#endif
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static const struct file_operations signalfd_fops = {
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#ifdef CONFIG_PROC_FS
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.show_fdinfo = signalfd_show_fdinfo,
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#endif
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.release = signalfd_release,
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.poll = signalfd_poll,
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.read = signalfd_read,
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.llseek = noop_llseek,
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};
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static int do_signalfd4(int ufd, sigset_t *mask, int flags)
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{
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struct signalfd_ctx *ctx;
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/* Check the SFD_* constants for consistency. */
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BUILD_BUG_ON(SFD_CLOEXEC != O_CLOEXEC);
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BUILD_BUG_ON(SFD_NONBLOCK != O_NONBLOCK);
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if (flags & ~(SFD_CLOEXEC | SFD_NONBLOCK))
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return -EINVAL;
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sigdelsetmask(mask, sigmask(SIGKILL) | sigmask(SIGSTOP));
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signotset(mask);
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if (ufd == -1) {
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ctx = kmalloc(sizeof(*ctx), GFP_KERNEL);
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if (!ctx)
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return -ENOMEM;
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ctx->sigmask = *mask;
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/*
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* When we call this, the initialization must be complete, since
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* anon_inode_getfd() will install the fd.
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*/
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ufd = anon_inode_getfd("[signalfd]", &signalfd_fops, ctx,
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O_RDWR | (flags & (O_CLOEXEC | O_NONBLOCK)));
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if (ufd < 0)
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kfree(ctx);
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} else {
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struct fd f = fdget(ufd);
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if (!f.file)
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return -EBADF;
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ctx = f.file->private_data;
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if (f.file->f_op != &signalfd_fops) {
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fdput(f);
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return -EINVAL;
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}
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spin_lock_irq(¤t->sighand->siglock);
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ctx->sigmask = *mask;
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spin_unlock_irq(¤t->sighand->siglock);
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wake_up(¤t->sighand->signalfd_wqh);
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fdput(f);
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}
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return ufd;
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}
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SYSCALL_DEFINE4(signalfd4, int, ufd, sigset_t __user *, user_mask,
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size_t, sizemask, int, flags)
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{
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sigset_t mask;
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if (sizemask != sizeof(sigset_t))
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return -EINVAL;
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if (copy_from_user(&mask, user_mask, sizeof(mask)))
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return -EFAULT;
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return do_signalfd4(ufd, &mask, flags);
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}
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SYSCALL_DEFINE3(signalfd, int, ufd, sigset_t __user *, user_mask,
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size_t, sizemask)
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{
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sigset_t mask;
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if (sizemask != sizeof(sigset_t))
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return -EINVAL;
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if (copy_from_user(&mask, user_mask, sizeof(mask)))
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return -EFAULT;
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return do_signalfd4(ufd, &mask, 0);
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}
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#ifdef CONFIG_COMPAT
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static long do_compat_signalfd4(int ufd,
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const compat_sigset_t __user *user_mask,
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compat_size_t sigsetsize, int flags)
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{
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sigset_t mask;
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if (sigsetsize != sizeof(compat_sigset_t))
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return -EINVAL;
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if (get_compat_sigset(&mask, user_mask))
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return -EFAULT;
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return do_signalfd4(ufd, &mask, flags);
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}
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COMPAT_SYSCALL_DEFINE4(signalfd4, int, ufd,
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const compat_sigset_t __user *, user_mask,
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compat_size_t, sigsetsize,
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int, flags)
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{
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return do_compat_signalfd4(ufd, user_mask, sigsetsize, flags);
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}
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COMPAT_SYSCALL_DEFINE3(signalfd, int, ufd,
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const compat_sigset_t __user *, user_mask,
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compat_size_t, sigsetsize)
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{
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return do_compat_signalfd4(ufd, user_mask, sigsetsize, 0);
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}
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#endif
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