Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753426AbZIKF1z (ORCPT ); Fri, 11 Sep 2009 01:27:55 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752631AbZIKF1u (ORCPT ); Fri, 11 Sep 2009 01:27:50 -0400 Received: from mx1.redhat.com ([209.132.183.28]:59977 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752479AbZIKF0S (ORCPT ); Fri, 11 Sep 2009 01:26:18 -0400 From: Eric Paris Subject: [PATCH 3/8] fanotify: fscking all notification system To: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, netdev@vger.kernel.org Cc: davem@davemloft.net, viro@zeniv.linux.org.uk, alan@linux.intel.com, hch@infradead.org Date: Fri, 11 Sep 2009 01:26:13 -0400 Message-ID: <20090911052613.32359.30717.stgit@paris.rdu.redhat.com> In-Reply-To: <20090911052558.32359.18075.stgit@paris.rdu.redhat.com> References: <20090911052558.32359.18075.stgit@paris.rdu.redhat.com> User-Agent: StGIT/0.14.3 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7758 Lines: 244 fanotify is a novel file notification system which bases notification on giving userspace both an event type (open, close, read, write) and an open file descriptor to the object in question. This should address a number of races and problems with other notification systems like inotify and dnotify and should allow the future implementation of blocking or access controlled notification. These are useful for on access scanners or hierachical storage management schemes. This patch just implements the basics of the fsnotify functions. Signed-off-by: Eric Paris --- fs/notify/Kconfig | 1 fs/notify/Makefile | 1 fs/notify/fanotify/Kconfig | 11 +++++ fs/notify/fanotify/Makefile | 1 fs/notify/fanotify/fanotify.c | 86 +++++++++++++++++++++++++++++++++++++++++ fs/notify/fanotify/fanotify.h | 12 ++++++ include/linux/Kbuild | 1 include/linux/fanotify.h | 40 +++++++++++++++++++ 8 files changed, 153 insertions(+), 0 deletions(-) create mode 100644 fs/notify/fanotify/Kconfig create mode 100644 fs/notify/fanotify/Makefile create mode 100644 fs/notify/fanotify/fanotify.c create mode 100644 fs/notify/fanotify/fanotify.h create mode 100644 include/linux/fanotify.h diff --git a/fs/notify/Kconfig b/fs/notify/Kconfig index dffbb09..22c629e 100644 --- a/fs/notify/Kconfig +++ b/fs/notify/Kconfig @@ -3,3 +3,4 @@ config FSNOTIFY source "fs/notify/dnotify/Kconfig" source "fs/notify/inotify/Kconfig" +source "fs/notify/fanotify/Kconfig" diff --git a/fs/notify/Makefile b/fs/notify/Makefile index 0922cc8..396a387 100644 --- a/fs/notify/Makefile +++ b/fs/notify/Makefile @@ -2,3 +2,4 @@ obj-$(CONFIG_FSNOTIFY) += fsnotify.o notification.o group.o inode_mark.o obj-y += dnotify/ obj-y += inotify/ +obj-y += fanotify/ diff --git a/fs/notify/fanotify/Kconfig b/fs/notify/fanotify/Kconfig new file mode 100644 index 0000000..70631ed --- /dev/null +++ b/fs/notify/fanotify/Kconfig @@ -0,0 +1,11 @@ +config FANOTIFY + bool "Filesystem wide access notification" + select FSNOTIFY + default y + ---help--- + Say Y here to enable fanotify suport. fanotify is a system wide + file access notification interface. Events are read from from a + socket and in doing so an fd is created in the reading process + which points to the same data as the one on which the event occured. + + If unsure, say Y. diff --git a/fs/notify/fanotify/Makefile b/fs/notify/fanotify/Makefile new file mode 100644 index 0000000..e7d39c0 --- /dev/null +++ b/fs/notify/fanotify/Makefile @@ -0,0 +1 @@ +obj-$(CONFIG_FANOTIFY) += fanotify.o diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c new file mode 100644 index 0000000..b5c2e32 --- /dev/null +++ b/fs/notify/fanotify/fanotify.c @@ -0,0 +1,86 @@ +#include +#include +#include +#include /* UINT_MAX */ +#include /* struct socket */ +#include /* task_struct */ +#include + +#include "fanotify.h" + +static int fanotify_handle_event(struct fsnotify_group *group, struct fsnotify_event *event) +{ + int ret; + + BUILD_BUG_ON(FAN_ACCESS != FS_ACCESS); + BUILD_BUG_ON(FAN_MODIFY != FS_MODIFY); + BUILD_BUG_ON(FAN_CLOSE_NOWRITE != FS_CLOSE_NOWRITE); + BUILD_BUG_ON(FAN_CLOSE_WRITE != FS_CLOSE_WRITE); + BUILD_BUG_ON(FAN_OPEN != FS_OPEN); + BUILD_BUG_ON(FAN_EVENT_ON_CHILD != FS_EVENT_ON_CHILD); + BUILD_BUG_ON(FAN_Q_OVERFLOW != FS_Q_OVERFLOW); + + ret = fsnotify_add_notify_event(group, event, NULL, NULL); + + return ret; +} + +static bool fanotify_should_send_event(struct fsnotify_group *group, struct inode *inode, + __u32 mask, void *data, int data_type) +{ + struct fsnotify_mark_entry *entry; + bool send; + + /* sorry, fanotify only gives a damn about files and dirs */ + if (!S_ISREG(inode->i_mode) && + !S_ISDIR(inode->i_mode)) + return false; + + /* if we don't have enough info to send an event to userspace say no */ + if ((data_type != FSNOTIFY_EVENT_FILE) && + (data_type != FSNOTIFY_EVENT_PATH)) + return false; + + /* if this file was opened by fanotify don't send events about it */ + if (data_type == FSNOTIFY_EVENT_FILE) { + struct file *file; + + file = (struct file *)data; + if (file->f_mode & FMODE_NONOTIFY) + return false; + } + + spin_lock(&inode->i_lock); + entry = fsnotify_find_mark_entry(group, inode); + spin_unlock(&inode->i_lock); + if (!entry) + return false; + + /* if the event is for a child and this inode doesn't care about + * events on the child, don't send it! */ + if ((mask & FS_EVENT_ON_CHILD) && + !(entry->mask & FS_EVENT_ON_CHILD)) + send = false; + else { + if (!(entry->mask & FS_EVENT_ON_CHILD) && + (mask & FS_EVENT_ON_CHILD)) + send = false; + else { + mask = (mask & ~FS_EVENT_ON_CHILD); + send = (entry->mask & mask); + } + } + + /* find took a reference */ + fsnotify_put_mark(entry); + + return send; +} + +const struct fsnotify_ops fanotify_ops = { + .handle_event = fanotify_handle_event, + .should_send_event = fanotify_should_send_event, + .free_group_priv = NULL, + .free_event_priv = NULL, + .freeing_mark = NULL, +}; diff --git a/fs/notify/fanotify/fanotify.h b/fs/notify/fanotify/fanotify.h new file mode 100644 index 0000000..a8785c1 --- /dev/null +++ b/fs/notify/fanotify/fanotify.h @@ -0,0 +1,12 @@ +#include +#include +#include +#include +#include + +static inline bool fanotify_is_mask_valid(__u32 mask) +{ + if (mask & ~(FAN_ALL_INCOMING_EVENTS)) + return false; + return true; +} diff --git a/include/linux/Kbuild b/include/linux/Kbuild index e7d84ff..b298c0e 100644 --- a/include/linux/Kbuild +++ b/include/linux/Kbuild @@ -206,6 +206,7 @@ unifdef-y += ethtool.h unifdef-y += eventpoll.h unifdef-y += signalfd.h unifdef-y += ext2_fs.h +unifdef-y += fanotify.h unifdef-y += fb.h unifdef-y += fcntl.h unifdef-y += filter.h diff --git a/include/linux/fanotify.h b/include/linux/fanotify.h new file mode 100644 index 0000000..b560f86 --- /dev/null +++ b/include/linux/fanotify.h @@ -0,0 +1,40 @@ +#ifndef _LINUX_FANOTIFY_H +#define _LINUX_FANOTIFY_H + +#include + +/* the following events that user-space can register for */ +#define FAN_ACCESS 0x00000001 /* File was accessed */ +#define FAN_MODIFY 0x00000002 /* File was modified */ +#define FAN_CLOSE_WRITE 0x00000008 /* Unwrittable file closed */ +#define FAN_CLOSE_NOWRITE 0x00000010 /* Writtable file closed */ +#define FAN_OPEN 0x00000020 /* File was opened */ + +#define FAN_EVENT_ON_CHILD 0x08000000 /* interested in child events */ + +/* FIXME currently Q's have no limit.... */ +#define FAN_Q_OVERFLOW 0x00004000 /* Event queued overflowed */ + +/* helper events */ +#define FAN_CLOSE (FAN_CLOSE_WRITE | FAN_CLOSE_NOWRITE) /* close */ + +/* + * All of the events - we build the list by hand so that we can add flags in + * the future and not break backward compatibility. Apps will get only the + * events that they originally wanted. Be sure to add new events here! + */ +#define FAN_ALL_EVENTS (FAN_ACCESS |\ + FAN_MODIFY |\ + FAN_CLOSE |\ + FAN_OPEN) + +/* + * All legal FAN bits userspace can request (although possibly not all + * at the same time. + */ +#define FAN_ALL_INCOMING_EVENTS (FAN_ALL_EVENTS |\ + FAN_EVENT_ON_CHILD) +#ifdef __KERNEL__ + +#endif /* __KERNEL__ */ +#endif /* _LINUX_FANOTIFY_H */ -- 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/