Retrieve multiple per-process signals through a file descriptor. Signed-off-by: Davi E. M. Arnaut --- Index: linux-2.6/fs/pollfs/signal.c =================================================================== --- /dev/null +++ linux-2.6/fs/pollfs/signal.c @@ -0,0 +1,144 @@ +/* + * sigtimedwait4, retrieve multiple signals with one call. + * + * Copyright (C) 2007 Davi E. M. Arnaut + * + * Licensed under the GNU GPL. See the file COPYING for details. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +struct pfs_signal { + sigset_t set; + spinlock_t lock; + struct task_struct *task; + struct pfs_file file; +}; + +static void inline sigset_adjust(sigset_t *set) +{ + /* SIGKILL and SIGSTOP cannot be caught, blocked, or ignored */ + sigdelsetmask(set, sigmask(SIGKILL) | sigmask(SIGSTOP)); + + /* Signals we don't want to dequeue */ + signotset(set); +} + +static ssize_t read(struct pfs_signal *evs, siginfo_t __user *infoup) +{ + int signo; + siginfo_t info; + + signo = dequeue_signal_lock(evs->task, &evs->set, &info); + if (!signo) + return -EAGAIN; + + if (copy_siginfo_to_user(infoup, &info)) + return -EFAULT; + + return 0; +} + +static ssize_t write(struct pfs_signal *evs, const sigset_t __user *uset) +{ + sigset_t set; + + if (copy_from_user(&set, uset, sizeof(sigset_t))) + return -EFAULT; + + sigset_adjust(&set); + + spin_lock_irq(&evs->lock); + sigemptyset(&evs->set); + sigorsets(&evs->set, &evs->set, &set); + spin_unlock_irq(&evs->lock); + + return 0; +} + +static int poll(struct pfs_signal *evs) +{ + int ret = 0; + sigset_t pending; + unsigned long flags; + + rcu_read_lock(); + + if (!lock_task_sighand(evs->task, &flags)) + goto out_unlock; + + sigorsets(&pending, &evs->task->pending.signal, + &evs->task->signal->shared_pending.signal); + + unlock_task_sighand(evs->task, &flags); + + spin_lock_irqsave(&evs->lock, flags); + signandsets(&pending, &pending, &evs->set); + spin_unlock_irqrestore(&evs->lock, flags); + + if (!sigisemptyset(&pending)) + ret = POLLIN; + +out_unlock: + rcu_read_unlock(); + + return ret; +} + +static int release(struct pfs_signal *evs) +{ + put_task_struct(evs->task); + kfree(evs); + + return 0; +} + +static const struct pfs_operations signal_ops = { + .read = PFS_READ(read, struct pfs_signal, siginfo_t), + .write = PFS_WRITE(write, struct pfs_signal, sigset_t), + .poll = PFS_POLL(poll, struct pfs_signal), + .release = PFS_RELEASE(release, struct pfs_signal), + .rsize = sizeof(siginfo_t), + .wsize = sizeof(sigset_t), +}; + +asmlinkage long sys_plsignal(const sigset_t __user *uset) +{ + long error; + struct pfs_signal *evs; + + evs = kmalloc(sizeof(*evs), GFP_KERNEL); + if (!evs) + return -ENOMEM; + + if (copy_from_user(&evs->set, uset, sizeof(sigset_t))) { + kfree(evs); + return -EFAULT; + } + + spin_lock_init(&evs->lock); + + evs->task = current; + get_task_struct(current); + + sigset_adjust(&evs->set); + + evs->file.data = evs; + evs->file.fops = &signal_ops; + evs->file.wait = &evs->task->sigwait; + + error = pfs_open(&evs->file); + if (error < 0) + release(evs); + + return error; +} Index: linux-2.6/fs/pollfs/Makefile =================================================================== --- linux-2.6.orig/fs/pollfs/Makefile +++ linux-2.6/fs/pollfs/Makefile @@ -1,2 +1,4 @@ obj-$(CONFIG_POLLFS) += pollfs.o pollfs-y := file.o + +pollfs-$(CONFIG_POLLFS_SIGNAL) += signal.o Index: linux-2.6/init/Kconfig =================================================================== --- linux-2.6.orig/init/Kconfig +++ linux-2.6/init/Kconfig @@ -469,6 +469,13 @@ config POLLFS help Pollfs support +config POLLFS_SIGNAL + bool "Enable pollfs signal" if EMBEDDED + default y + depends on POLLFS + help + Pollable signal support + config SHMEM bool "Use full shmem filesystem" if EMBEDDED default y -- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/