[PATCH 2/2] Filesystem: Add kernel event filter handler

Sebastian Huber sebastian.huber at embedded-brains.de
Thu Oct 31 14:49:51 UTC 2013


This handler is necessary to implement the KQUEUE(2) system calls.

Add <sys/event.h> from FreeBSD 8.3.
---
 cpukit/Makefile.am                           |    1 +
 cpukit/libcsupport/include/rtems/libio.h     |   31 +++
 cpukit/libcsupport/include/sys/event.h       |  279 ++++++++++++++++++++++++++
 cpukit/libfs/Makefile.am                     |    1 +
 cpukit/libfs/src/defaults/default_kqfilter.c |   38 ++++
 cpukit/preinstall.am                         |    4 +
 6 files changed, 354 insertions(+), 0 deletions(-)
 create mode 100644 cpukit/libcsupport/include/sys/event.h
 create mode 100644 cpukit/libfs/src/defaults/default_kqfilter.c

diff --git a/cpukit/Makefile.am b/cpukit/Makefile.am
index 443ed35..3e26cac 100644
--- a/cpukit/Makefile.am
+++ b/cpukit/Makefile.am
@@ -50,6 +50,7 @@ include_HEADERS += libmd/md4.h
 include_HEADERS += libmd/md5.h
 
 include_sys_HEADERS += libcsupport/include/sys/ioccom.h
+include_sys_HEADERS += libcsupport/include/sys/event.h
 include_sys_HEADERS += libcsupport/include/sys/filio.h
 include_sys_HEADERS += libcsupport/include/sys/ioctl.h
 include_sys_HEADERS += libcsupport/include/sys/poll.h
diff --git a/cpukit/libcsupport/include/rtems/libio.h b/cpukit/libcsupport/include/rtems/libio.h
index a642062..21d57eb 100644
--- a/cpukit/libcsupport/include/rtems/libio.h
+++ b/cpukit/libcsupport/include/rtems/libio.h
@@ -41,6 +41,8 @@
 extern "C" {
 #endif
 
+struct knote;
+
 /**
  * @defgroup LibIOFSOps File System Operations
  *
@@ -958,6 +960,22 @@ typedef int (*rtems_filesystem_poll_t)(
 );
 
 /**
+ * @brief Kernel event filter support.
+ *
+ * @param[in, out] iop The IO pointer.
+ * @param[in] kn The kernel event note.
+ *
+ * @retval 0 Successful operation.
+ * @retval error An error occurred.  This is usually EINVAL.
+ *
+ * @see rtems_filesystem_default_kqfilter().
+ */
+typedef int (*rtems_filesystem_kqfilter_t)(
+  rtems_libio_t *iop,
+  struct knote *kn
+);
+
+/**
  * @brief File system node operations table.
  */
 struct _rtems_filesystem_file_handlers_r {
@@ -973,6 +991,7 @@ struct _rtems_filesystem_file_handlers_r {
   rtems_filesystem_fdatasync_t fdatasync_h;
   rtems_filesystem_fcntl_t fcntl_h;
   rtems_filesystem_poll_t poll_h;
+  rtems_filesystem_kqfilter_t kqfilter_h;
 };
 
 /**
@@ -1158,6 +1177,18 @@ int rtems_filesystem_default_poll(
   int events
 );
 
+/**
+ * @brief Default kernel event filter handler.
+ *
+ * @retval EINVAL Always.
+ *
+ * @see rtems_filesystem_kqfilter_t.
+ */
+int rtems_filesystem_default_kqfilter(
+  rtems_libio_t *iop,
+  struct knote *kn
+);
+
 /** @} */
 
 /**
diff --git a/cpukit/libcsupport/include/sys/event.h b/cpukit/libcsupport/include/sys/event.h
new file mode 100644
index 0000000..d92eb55
--- /dev/null
+++ b/cpukit/libcsupport/include/sys/event.h
@@ -0,0 +1,279 @@
+/*-
+ * Copyright (c) 1999,2000,2001 Jonathan Lemon <jlemon at FreeBSD.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+#ifndef _SYS_EVENT_H_
+#define _SYS_EVENT_H_
+
+#include <sys/queue.h> 
+
+#define EVFILT_READ		(-1)
+#define EVFILT_WRITE		(-2)
+#define EVFILT_AIO		(-3)	/* attached to aio requests */
+#define EVFILT_VNODE		(-4)	/* attached to vnodes */
+#define EVFILT_PROC		(-5)	/* attached to struct proc */
+#define EVFILT_SIGNAL		(-6)	/* attached to struct proc */
+#define EVFILT_TIMER		(-7)	/* timers */
+/*	EVFILT_NETDEV		(-8)	   no longer supported */
+#define EVFILT_FS		(-9)	/* filesystem events */
+#define EVFILT_LIO		(-10)	/* attached to lio requests */
+#define EVFILT_USER		(-11)	/* User events */
+#define EVFILT_SYSCOUNT		11
+
+#define EV_SET(kevp_, a, b, c, d, e, f) do {	\
+	struct kevent *kevp = (kevp_);		\
+	(kevp)->ident = (a);			\
+	(kevp)->filter = (b);			\
+	(kevp)->flags = (c);			\
+	(kevp)->fflags = (d);			\
+	(kevp)->data = (e);			\
+	(kevp)->udata = (f);			\
+} while(0)
+
+struct kevent {
+	uintptr_t	ident;		/* identifier for this event */
+	short		filter;		/* filter for event */
+	u_short		flags;
+	u_int		fflags;
+	intptr_t	data;
+	void		*udata;		/* opaque user data identifier */
+};
+
+/* actions */
+#define EV_ADD		0x0001		/* add event to kq (implies enable) */
+#define EV_DELETE	0x0002		/* delete event from kq */
+#define EV_ENABLE	0x0004		/* enable event */
+#define EV_DISABLE	0x0008		/* disable event (not reported) */
+
+/* flags */
+#define EV_ONESHOT	0x0010		/* only report one occurrence */
+#define EV_CLEAR	0x0020		/* clear event state after reporting */
+#define EV_RECEIPT	0x0040		/* force EV_ERROR on success, data=0 */
+#define EV_DISPATCH	0x0080		/* disable event after reporting */
+
+#define EV_SYSFLAGS	0xF000		/* reserved by system */
+#define EV_FLAG1	0x2000		/* filter-specific flag */
+
+/* returned values */
+#define EV_EOF		0x8000		/* EOF detected */
+#define EV_ERROR	0x4000		/* error, data contains errno */
+
+ /*
+  * data/hint flags/masks for EVFILT_USER, shared with userspace
+  *
+  * On input, the top two bits of fflags specifies how the lower twenty four
+  * bits should be applied to the stored value of fflags.
+  *
+  * On output, the top two bits will always be set to NOTE_FFNOP and the
+  * remaining twenty four bits will contain the stored fflags value.
+  */
+#define NOTE_FFNOP	0x00000000		/* ignore input fflags */
+#define NOTE_FFAND	0x40000000		/* AND fflags */
+#define NOTE_FFOR	0x80000000		/* OR fflags */
+#define NOTE_FFCOPY	0xc0000000		/* copy fflags */
+#define NOTE_FFCTRLMASK	0xc0000000		/* masks for operations */
+#define NOTE_FFLAGSMASK	0x00ffffff
+
+#define NOTE_TRIGGER	0x01000000		/* Cause the event to be
+						   triggered for output. */
+
+/*
+ * data/hint flags for EVFILT_{READ|WRITE}, shared with userspace
+ */
+#define NOTE_LOWAT	0x0001			/* low water mark */
+
+/*
+ * data/hint flags for EVFILT_VNODE, shared with userspace
+ */
+#define	NOTE_DELETE	0x0001			/* vnode was removed */
+#define	NOTE_WRITE	0x0002			/* data contents changed */
+#define	NOTE_EXTEND	0x0004			/* size increased */
+#define	NOTE_ATTRIB	0x0008			/* attributes changed */
+#define	NOTE_LINK	0x0010			/* link count changed */
+#define	NOTE_RENAME	0x0020			/* vnode was renamed */
+#define	NOTE_REVOKE	0x0040			/* vnode access was revoked */
+
+/*
+ * data/hint flags for EVFILT_PROC, shared with userspace
+ */
+#define	NOTE_EXIT	0x80000000		/* process exited */
+#define	NOTE_FORK	0x40000000		/* process forked */
+#define	NOTE_EXEC	0x20000000		/* process exec'd */
+#define	NOTE_PCTRLMASK	0xf0000000		/* mask for hint bits */
+#define	NOTE_PDATAMASK	0x000fffff		/* mask for pid */
+
+/* additional flags for EVFILT_PROC */
+#define	NOTE_TRACK	0x00000001		/* follow across forks */
+#define	NOTE_TRACKERR	0x00000002		/* could not track child */
+#define	NOTE_CHILD	0x00000004		/* am a child process */
+
+struct knote;
+SLIST_HEAD(klist, knote);
+struct kqueue;
+SLIST_HEAD(kqlist, kqueue);
+struct knlist {
+	struct	klist	kl_list;
+	void    (*kl_lock)(void *);	/* lock function */
+	void    (*kl_unlock)(void *);
+	void	(*kl_assert_locked)(void *);
+	void	(*kl_assert_unlocked)(void *);
+	void *kl_lockarg;		/* argument passed to kl_lockf() */
+};
+
+
+#ifdef _KERNEL
+
+#ifdef MALLOC_DECLARE
+MALLOC_DECLARE(M_KQUEUE);
+#endif
+
+/*
+ * Flags for knote call
+ */
+#define	KNF_LISTLOCKED	0x0001			/* knlist is locked */
+#define	KNF_NOKQLOCK	0x0002			/* do not keep KQ_LOCK */
+
+#define KNOTE(list, hist, flags)	knote(list, hist, flags)
+#define KNOTE_LOCKED(list, hint)	knote(list, hint, KNF_LISTLOCKED)
+#define KNOTE_UNLOCKED(list, hint)	knote(list, hint, 0)
+
+#define	KNLIST_EMPTY(list)		SLIST_EMPTY(&(list)->kl_list)
+
+/*
+ * Flag indicating hint is a signal.  Used by EVFILT_SIGNAL, and also
+ * shared by EVFILT_PROC  (all knotes attached to p->p_klist)
+ */
+#define NOTE_SIGNAL	0x08000000
+
+/*
+ * Hint values for the optional f_touch event filter.  If f_touch is not set 
+ * to NULL and f_isfd is zero the f_touch filter will be called with the type
+ * argument set to EVENT_REGISTER during a kevent() system call.  It is also
+ * called under the same conditions with the type argument set to EVENT_PROCESS
+ * when the event has been triggered.
+ */
+#define EVENT_REGISTER	1
+#define EVENT_PROCESS	2
+
+struct filterops {
+	int	f_isfd;		/* true if ident == filedescriptor */
+	int	(*f_attach)(struct knote *kn);
+	void	(*f_detach)(struct knote *kn);
+	int	(*f_event)(struct knote *kn, long hint);
+	void	(*f_touch)(struct knote *kn, struct kevent *kev, u_long type);
+};
+
+/*
+ * Setting the KN_INFLUX flag enables you to unlock the kq that this knote
+ * is on, and modify kn_status as if you had the KQ lock.
+ *
+ * kn_sfflags, kn_sdata, and kn_kevent are protected by the knlist lock.
+ */
+struct knote {
+	SLIST_ENTRY(knote)	kn_link;	/* for kq */
+	SLIST_ENTRY(knote)	kn_selnext;	/* for struct selinfo */
+	struct			knlist *kn_knlist;	/* f_attach populated */
+	TAILQ_ENTRY(knote)	kn_tqe;
+	struct			kqueue *kn_kq;	/* which queue we are on */
+	struct 			kevent kn_kevent;
+	int			kn_status;	/* protected by kq lock */
+#define KN_ACTIVE	0x01			/* event has been triggered */
+#define KN_QUEUED	0x02			/* event is on queue */
+#define KN_DISABLED	0x04			/* event is disabled */
+#define KN_DETACHED	0x08			/* knote is detached */
+#define KN_INFLUX	0x10			/* knote is in flux */
+#define KN_MARKER	0x20			/* ignore this knote */
+#define KN_KQUEUE	0x40			/* this knote belongs to a kq */
+#define KN_HASKQLOCK	0x80			/* for _inevent */
+	int			kn_sfflags;	/* saved filter flags */
+	intptr_t		kn_sdata;	/* saved data field */
+	union {
+		struct		file *p_fp;	/* file data pointer */
+		struct		proc *p_proc;	/* proc pointer */
+		struct		aiocblist *p_aio;	/* AIO job pointer */
+		struct		aioliojob *p_lio;	/* LIO job pointer */ 
+	} kn_ptr;
+	struct			filterops *kn_fop;
+	void			*kn_hook;
+	int			kn_hookid;
+
+#define kn_id		kn_kevent.ident
+#define kn_filter	kn_kevent.filter
+#define kn_flags	kn_kevent.flags
+#define kn_fflags	kn_kevent.fflags
+#define kn_data		kn_kevent.data
+#define kn_fp		kn_ptr.p_fp
+};
+struct kevent_copyops {
+	void	*arg;
+	int	(*k_copyout)(void *arg, struct kevent *kevp, int count);
+	int	(*k_copyin)(void *arg, struct kevent *kevp, int count);
+};
+
+struct thread;
+struct proc;
+struct knlist;
+struct mtx;
+
+extern void	knote(struct knlist *list, long hint, int lockflags);
+extern void	knote_fork(struct knlist *list, int pid);
+extern void	knlist_add(struct knlist *knl, struct knote *kn, int islocked);
+extern void	knlist_remove(struct knlist *knl, struct knote *kn, int islocked);
+extern void	knlist_remove_inevent(struct knlist *knl, struct knote *kn);
+extern int	knlist_empty(struct knlist *knl);
+extern void	knlist_init(struct knlist *knl, void *lock,
+    void (*kl_lock)(void *), void (*kl_unlock)(void *),
+    void (*kl_assert_locked)(void *), void (*kl_assert_unlocked)(void *));
+extern void	knlist_init_mtx(struct knlist *knl, struct mtx *lock);
+extern void	knlist_destroy(struct knlist *knl);
+extern void	knlist_cleardel(struct knlist *knl, struct thread *td,
+	int islocked, int killkn);
+#define knlist_clear(knl, islocked)				\
+		knlist_cleardel((knl), NULL, (islocked), 0)
+#define knlist_delete(knl, td, islocked)			\
+		knlist_cleardel((knl), (td), (islocked), 1)
+extern void	knote_fdclose(struct thread *p, int fd);
+extern int 	kqfd_register(int fd, struct kevent *kev, struct thread *p,
+		    int waitok);
+extern int	kqueue_add_filteropts(int filt, struct filterops *filtops);
+extern int	kqueue_del_filteropts(int filt);
+
+#else 	/* !_KERNEL */
+
+#include <sys/cdefs.h>
+struct timespec;
+
+__BEGIN_DECLS
+int     kqueue(void);
+int     kevent(int kq, const struct kevent *changelist, int nchanges,
+	    struct kevent *eventlist, int nevents,
+	    const struct timespec *timeout);
+__END_DECLS
+
+#endif /* !_KERNEL */
+
+#endif /* !_SYS_EVENT_H_ */
diff --git a/cpukit/libfs/Makefile.am b/cpukit/libfs/Makefile.am
index b8496d5..21bb7ef 100644
--- a/cpukit/libfs/Makefile.am
+++ b/cpukit/libfs/Makefile.am
@@ -33,6 +33,7 @@ libdefaultfs_a_SOURCES = \
     src/defaults/default_node_type.c \
     src/defaults/default_ftruncate_directory.c \
     src/defaults/default_handlers.c src/defaults/default_ops.c
+libdefaultfs_a_SOURCES += src/defaults/default_kqfilter.c
 libdefaultfs_a_SOURCES += src/defaults/default_poll.c
 
 noinst_LIBRARIES += libimfs.a
diff --git a/cpukit/libfs/src/defaults/default_kqfilter.c b/cpukit/libfs/src/defaults/default_kqfilter.c
new file mode 100644
index 0000000..6c84539
--- /dev/null
+++ b/cpukit/libfs/src/defaults/default_kqfilter.c
@@ -0,0 +1,38 @@
+/**
+ * @file
+ *
+ * @brief Default Kernel Event Filter Handler
+ *
+ * @ingroup LibIOFSHandler
+ */
+
+/*
+ * Copyright (c) 2013 embedded brains GmbH.  All rights reserved.
+ *
+ *  embedded brains GmbH
+ *  Dornierstr. 4
+ *  82178 Puchheim
+ *  Germany
+ *  <rtems at embedded-brains.de>
+ *
+ * The license and distribution terms for this file may be
+ * found in the file LICENSE in this distribution or at
+ * http://www.rtems.com/license/LICENSE.
+ */
+
+#if HAVE_CONFIG_H
+  #include "config.h"
+#endif
+
+#include <rtems/libio_.h>
+
+#include <sys/types.h>
+#include <sys/event.h>
+
+int rtems_filesystem_default_kqfilter(
+  rtems_libio_t *iop,
+  struct knote *kn
+)
+{
+  return EINVAL;
+}
diff --git a/cpukit/preinstall.am b/cpukit/preinstall.am
index bdcc359..4e80a3f 100644
--- a/cpukit/preinstall.am
+++ b/cpukit/preinstall.am
@@ -68,6 +68,10 @@ $(PROJECT_INCLUDE)/sys/ioccom.h: libcsupport/include/sys/ioccom.h $(PROJECT_INCL
 	$(INSTALL_DATA) $< $(PROJECT_INCLUDE)/sys/ioccom.h
 PREINSTALL_FILES += $(PROJECT_INCLUDE)/sys/ioccom.h
 
+$(PROJECT_INCLUDE)/sys/event.h: libcsupport/include/sys/event.h $(PROJECT_INCLUDE)/sys/$(dirstamp)
+	$(INSTALL_DATA) $< $(PROJECT_INCLUDE)/sys/event.h
+PREINSTALL_FILES += $(PROJECT_INCLUDE)/sys/event.h
+
 $(PROJECT_INCLUDE)/sys/filio.h: libcsupport/include/sys/filio.h $(PROJECT_INCLUDE)/sys/$(dirstamp)
 	$(INSTALL_DATA) $< $(PROJECT_INCLUDE)/sys/filio.h
 PREINSTALL_FILES += $(PROJECT_INCLUDE)/sys/filio.h
-- 
1.7.7




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