This patch is added two flags SFD_SHARED_QUEUE and SFD_PER_THREAD_QUEUE SFD_SHARED_QUEUE - read signals from a shared (process wide) queue SFD_PER_THREAD_QUEUE - read signals from a per-thread queue
Without these flags or with both flags signals are read from both queues. This functionality is required for dumping pending signals. Cc: Alexander Viro <[email protected]> Cc: "Paul E. McKenney" <[email protected]> Cc: David Howells <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Oleg Nesterov <[email protected]> Cc: Michael Kerrisk <[email protected]> Cc: Pavel Emelyanov <[email protected]> CC: Cyrill Gorcunov <[email protected]> Signed-off-by: Andrey Vagin <[email protected]> --- fs/signalfd.c | 30 ++++++++++++++++++++++-------- include/uapi/linux/signalfd.h | 4 ++++ 2 files changed, 26 insertions(+), 8 deletions(-) diff --git a/fs/signalfd.c b/fs/signalfd.c index c723b5d..8019ec9 100644 --- a/fs/signalfd.c +++ b/fs/signalfd.c @@ -61,13 +61,17 @@ static unsigned int signalfd_poll(struct file *file, poll_table *wait) { struct signalfd_ctx *ctx = file->private_data; unsigned int events = 0; + unsigned int flags = file->f_flags; 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)) + if ((flags & SFD_PER_THREAD_QUEUE) && + next_signal(¤t->pending, &ctx->sigmask)) + events |= POLLIN; + + if ((flags & SFD_SHARED_QUEUE) && + next_signal(¤t->signal->shared_pending, &ctx->sigmask)) events |= POLLIN; spin_unlock_irq(¤t->sighand->siglock); @@ -189,13 +193,13 @@ static int signalfd_copyinfo(struct signalfd_siginfo __user *uinfo, } static ssize_t signalfd_dequeue(struct signalfd_ctx *ctx, siginfo_t *info, - int nonblock) + int nonblock, int qmask) { ssize_t ret; DECLARE_WAITQUEUE(wait, current); spin_lock_irq(¤t->sighand->siglock); - ret = dequeue_signal(current, &ctx->sigmask, info); + ret = do_dequeue_signal(current, &ctx->sigmask, info, qmask); switch (ret) { case 0: if (!nonblock) @@ -209,7 +213,7 @@ static ssize_t signalfd_dequeue(struct signalfd_ctx *ctx, siginfo_t *info, add_wait_queue(¤t->sighand->signalfd_wqh, &wait); for (;;) { set_current_state(TASK_INTERRUPTIBLE); - ret = dequeue_signal(current, &ctx->sigmask, info); + ret = do_dequeue_signal(current, &ctx->sigmask, info, qmask); if (ret != 0) break; if (signal_pending(current)) { @@ -240,16 +244,23 @@ static ssize_t signalfd_read(struct file *file, char __user *buf, size_t count, struct signalfd_siginfo __user *siginfo; int nonblock = file->f_flags & O_NONBLOCK; bool raw = file->f_flags & SFD_RAW; + int qmask = 0; ssize_t ret, total = 0; siginfo_t info; + if (file->f_flags & SFD_PER_THREAD_QUEUE) + qmask |= SIGQUEUE_PRIVATE; + if (file->f_flags & SFD_SHARED_QUEUE) + qmask |= SIGQUEUE_SHARED; + count /= sizeof(struct signalfd_siginfo); if (!count) return -EINVAL; siginfo = (struct signalfd_siginfo __user *) buf; do { - ret = signalfd_dequeue(ctx, &info, nonblock); + ret = signalfd_dequeue(ctx, &info, nonblock, qmask); + if (unlikely(ret <= 0)) break; @@ -292,6 +303,8 @@ static const struct file_operations signalfd_fops = { .llseek = noop_llseek, }; +#define SFD_QUEUES (SFD_SHARED_QUEUE | SFD_PER_THREAD_QUEUE) + SYSCALL_DEFINE4(signalfd4, int, ufd, sigset_t __user *, user_mask, size_t, sizemask, int, flags) { @@ -302,7 +315,7 @@ SYSCALL_DEFINE4(signalfd4, int, ufd, sigset_t __user *, user_mask, BUILD_BUG_ON(SFD_CLOEXEC != O_CLOEXEC); BUILD_BUG_ON(SFD_NONBLOCK != O_NONBLOCK); - if (flags & ~(SFD_CLOEXEC | SFD_NONBLOCK | SFD_RAW)) + if (flags & ~(SFD_CLOEXEC | SFD_NONBLOCK | SFD_RAW | SFD_QUEUES)) return -EINVAL; if (sizemask != sizeof(sigset_t) || @@ -338,6 +351,7 @@ SYSCALL_DEFINE4(signalfd4, int, ufd, sigset_t __user *, user_mask, goto out; } + file->f_flags |= (flags & SFD_QUEUES) ? : SFD_QUEUES; file->f_flags |= flags & SFD_RAW; fd_install(ufd, file); diff --git a/include/uapi/linux/signalfd.h b/include/uapi/linux/signalfd.h index bc31849..481b658 100644 --- a/include/uapi/linux/signalfd.h +++ b/include/uapi/linux/signalfd.h @@ -16,6 +16,10 @@ #define SFD_CLOEXEC O_CLOEXEC #define SFD_NONBLOCK O_NONBLOCK #define SFD_RAW O_DIRECT +/* Read signals from a shared (process wide) queue */ +#define SFD_SHARED_QUEUE O_DIRECTORY +/* Read signals from a per-thread queue */ +#define SFD_PER_THREAD_QUEUE O_EXCL struct signalfd_siginfo { __u32 ssi_signo; -- 1.7.11.7 -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
