[patch 2/9] signalfd/timerfd v3 - signalfd core ...
This patch series implements the new signalfd() system call.
I took part of the original Linus code (and you know how
badly it can be broken :), and I added even more breakage ;)
Signals are fetched from the same signal queue used by the process,
so signalfd will compete with standard kernel delivery in dequeue_signal().
If you want to reliably fetch signals on the signalfd file, you need to
block them with sigprocmask(SIG_BLOCK).
This seems to be working fine on my Dual Opteron machine. I made a quick
test program for it:
http://www.xmailserver.org/signafd-test.c
The signalfd() system call implements signal delivery into a file
descriptor receiver. The signalfd file descriptor if created with the
following API:
int signalfd(int ufd, const sigset_t *mask, size_t masksize);
The "ufd" parameter allows to change an existing signalfd sigmask, w/out
going to close/create cycle (Linus idea). Use "ufd" == -1 if you want a
brand new signalfd file.
The "mask" allows to specify the signal mask of signals that we are
interested in. The "masksize" parameter is the size of "mask".
The signalfd fd supports the poll(2) and read(2) system calls. The poll(2)
will return POLLIN when signals are available to be dequeued. As a direct
consequence of supporting the Linux poll subsystem, the signalfd fd can use
used together with epoll(2) too.
The read(2) system call will return a "struct signalfd_siginfo" structure
in the userspace supplied buffer. The return value is the number of bytes
copied in the supplied buffer, or -1 in case of error. The read(2) call
can also return 0, in case the sighand structure to which the signalfd
was attached, has been orphaned. The O_NONBLOCK flag is also supported, and
read(2) will return -EAGAIN in case no signal is available.
The format of the struct signalfd_siginfo is, and the valid fields depends
of the (->code & __SI_MASK) value, in the same way a struct siginfo would:
struct signalfd_siginfo {
__u32 signo;/* si_signo */
__s32 err; /* si_errno */
__s32 code; /* si_code */
__u32 pid; /* si_pid */
__u32 uid; /* si_uid */
__s32 fd; /* si_fd */
__u32 tid; /* si_fd */
__u32 band; /* si_band */
__u32 overrun; /* si_overrun */
__u32 trapno; /* si_trapno */
__s32 status; /* si_status */
__s32 svint;/* si_int */
__u64 svptr;/* si_ptr */
__u64 utime;/* si_utime */
__u64 stime;/* si_stime */
__u64 addr; /* si_addr */
};
Signed-off-by: Davide Libenzi
- Davide
Index: linux-2.6.20.ep2/fs/signalfd.c
===
--- /dev/null 1970-01-01 00:00:00.0 +
+++ linux-2.6.20.ep2/fs/signalfd.c 2007-03-11 14:28:37.0 -0700
@@ -0,0 +1,381 @@
+/*
+ * fs/signalfd.c
+ *
+ * Copyright (C) 2003 Linus Torvalds
+ *
+ * Mon Mar 5, 2007: Davide Libenzi
+ * 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.
+ */
+
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+
+#include
+
+
+
+struct signalfd_ctx {
+ struct list_head lnk;
+ wait_queue_head_t wqh;
+ sigset_t sigmask;
+ struct task_struct *tsk;
+};
+
+
+
+static struct sighand_struct *signalfd_get_sighand(struct signalfd_ctx *ctx,
+ unsigned long *flags);
+static void signalfd_put_sighand(struct signalfd_ctx *ctx,
+struct sighand_struct *sighand,
+unsigned long *flags);
+static void signalfd_cleanup(struct signalfd_ctx *ctx);
+static int signalfd_close(struct inode *inode, struct file *file);
+static unsigned int signalfd_poll(struct file *file, poll_table *wait);
+static int signalfd_copyinfo(struct signalfd_siginfo __user *uinfo,
+siginfo_t const *kinfo);
+static ssize_t signalfd_read(struct file *file, char __user *buf, size_t count,
+loff_t *ppos);
+
+
+
+static const struct file_operations signalfd_fops = {
+ .release= signalfd_close,
+ .poll = signalfd_poll,
+ .read = signalfd_read,
+};
+static struct kmem_cache *signalfd_ctx_cachep;
+
+
+
+static struct sighand_struct *signalfd_get_sighand(struct signalfd_ctx *ctx,
+ unsigned long *flags)
+{
+ struct sighand_struct *sighand;
+
+ rcu_read_lock();
+ sighand = lock_task_sighand(ctx->tsk, flags);
+ rcu_read_unlock();
+
+ if (sighand && list_empty(>lnk)) {
+
[patch 2/9] signalfd/timerfd v3 - signalfd core ...
This patch series implements the new signalfd() system call.
I took part of the original Linus code (and you know how
badly it can be broken :), and I added even more breakage ;)
Signals are fetched from the same signal queue used by the process,
so signalfd will compete with standard kernel delivery in dequeue_signal().
If you want to reliably fetch signals on the signalfd file, you need to
block them with sigprocmask(SIG_BLOCK).
This seems to be working fine on my Dual Opteron machine. I made a quick
test program for it:
http://www.xmailserver.org/signafd-test.c
The signalfd() system call implements signal delivery into a file
descriptor receiver. The signalfd file descriptor if created with the
following API:
int signalfd(int ufd, const sigset_t *mask, size_t masksize);
The ufd parameter allows to change an existing signalfd sigmask, w/out
going to close/create cycle (Linus idea). Use ufd == -1 if you want a
brand new signalfd file.
The mask allows to specify the signal mask of signals that we are
interested in. The masksize parameter is the size of mask.
The signalfd fd supports the poll(2) and read(2) system calls. The poll(2)
will return POLLIN when signals are available to be dequeued. As a direct
consequence of supporting the Linux poll subsystem, the signalfd fd can use
used together with epoll(2) too.
The read(2) system call will return a struct signalfd_siginfo structure
in the userspace supplied buffer. The return value is the number of bytes
copied in the supplied buffer, or -1 in case of error. The read(2) call
can also return 0, in case the sighand structure to which the signalfd
was attached, has been orphaned. The O_NONBLOCK flag is also supported, and
read(2) will return -EAGAIN in case no signal is available.
The format of the struct signalfd_siginfo is, and the valid fields depends
of the (-code __SI_MASK) value, in the same way a struct siginfo would:
struct signalfd_siginfo {
__u32 signo;/* si_signo */
__s32 err; /* si_errno */
__s32 code; /* si_code */
__u32 pid; /* si_pid */
__u32 uid; /* si_uid */
__s32 fd; /* si_fd */
__u32 tid; /* si_fd */
__u32 band; /* si_band */
__u32 overrun; /* si_overrun */
__u32 trapno; /* si_trapno */
__s32 status; /* si_status */
__s32 svint;/* si_int */
__u64 svptr;/* si_ptr */
__u64 utime;/* si_utime */
__u64 stime;/* si_stime */
__u64 addr; /* si_addr */
};
Signed-off-by: Davide Libenzi davidel@xmailserver.org
- Davide
Index: linux-2.6.20.ep2/fs/signalfd.c
===
--- /dev/null 1970-01-01 00:00:00.0 +
+++ linux-2.6.20.ep2/fs/signalfd.c 2007-03-11 14:28:37.0 -0700
@@ -0,0 +1,381 @@
+/*
+ * 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.
+ */
+
+#include linux/file.h
+#include linux/poll.h
+#include linux/slab.h
+#include linux/init.h
+#include linux/fs.h
+#include linux/mount.h
+#include linux/module.h
+#include linux/kernel.h
+#include linux/signal.h
+#include linux/list.h
+#include linux/anon_inodes.h
+#include linux/signalfd.h
+
+#include asm/uaccess.h
+
+
+
+struct signalfd_ctx {
+ struct list_head lnk;
+ wait_queue_head_t wqh;
+ sigset_t sigmask;
+ struct task_struct *tsk;
+};
+
+
+
+static struct sighand_struct *signalfd_get_sighand(struct signalfd_ctx *ctx,
+ unsigned long *flags);
+static void signalfd_put_sighand(struct signalfd_ctx *ctx,
+struct sighand_struct *sighand,
+unsigned long *flags);
+static void signalfd_cleanup(struct signalfd_ctx *ctx);
+static int signalfd_close(struct inode *inode, struct file *file);
+static unsigned int signalfd_poll(struct file *file, poll_table *wait);
+static int signalfd_copyinfo(struct signalfd_siginfo __user *uinfo,
+siginfo_t const *kinfo);
+static ssize_t signalfd_read(struct file *file, char __user *buf, size_t count,
+loff_t *ppos);
+
+
+
+static const struct file_operations signalfd_fops = {
+ .release= signalfd_close,
+ .poll = signalfd_poll,
+ .read = signalfd_read,
+};
+static struct kmem_cache *signalfd_ctx_cachep;
+
+
+
+static struct sighand_struct *signalfd_get_sighand(struct signalfd_ctx *ctx,
+ unsigned long *flags)
