Compared with Filesystem Events Reporter v1, the following changes are done:
- Use workqueue/keventd instead of kfseventd.
- fsevent_mask can be set by sysctl and proc
interface.
- Add missed spinlock
- Ensure fsevent sequence number is uniqe
This patch implements a filsystem events report facitily, Filesystem Events
Reporter, the user can monitor filesystem activities via it, currently, it
can monitor access, attribute change, open, create, modify, delete,
move and close of any file or directory as well as mount/umount.
Every filesystem event will include tgid, uid and gid of the process
which triggered this event, process name, file or directory name
operated by it.
Filesystem Events Reporter is never a duplicate of inotify, inotify
just concerns change on file or directory, Beagle uses it to watch
file changes in order to regenerate index for it, inotify can't tell
us who did that change and what is its process name, but filesystem
events reporter can do these, moreover inotify's overhead is greater
than filesystem events reporter, inotify needs compare inode with
watched file or directories list to decide whether it should generate an
inotify_event, some locks also increase overhead, filesystem event
connector hasn't these overhead, it just generates a fsevent and send.
To be important, filesystem event reporter doesn't add any new system
call, the user space application can make use of it by netlink socket,
but inotify added several system calls, many events mechanism in kernel
have used netlink as communication way with user space, for example,
KOBJECT_UEVENT, PROC_EVENTS, to use netlink will make it more possible
to unify events interface to netlink, the user space application can use
it very easy.
Every application using fsevent can set its own fsevent filter list
without effect in other applications using fsevent, there are three
filter lists, they are pid filter list, uid filetr list and gid
filter list, respectively, moreover, there is a fsevent mask used to
control those fsevents which fail to match three filter lists, an
application using fsevent can listen those fsevents it want to
monitor and ignore those fsevents it doesn't interest in by set
series of filters, there is a fsevent mask used to take effects on
all the applications using fsevent, it can be set by sysctl and proc
interface.
fs/Kconfig | 10
fs/Makefile | 1
fs/fsevent.c | 598 +++++++++++++++++++++++++++++++++++++++++++++++
fs/namespace.c | 12
include/linux/fsevent.h | 131 ++++++++++
include/linux/fsnotify.h | 37 ++
include/linux/netlink.h | 1
7 files changed, 790 insertions(+)
Signed-off-by: Yi Yang <[email protected]>
--- a/include/linux/netlink.h.orig 2006-03-31 22:58:50.000000000 +0800
+++ b/include/linux/netlink.h 2006-04-05 20:34:23.000000000 +0800
@@ -21,6 +21,7 @@
#define NETLINK_DNRTMSG 14 /* DECnet routing messages */
#define NETLINK_KOBJECT_UEVENT 15 /* Kernel messages to userspace */
#define NETLINK_GENERIC 16
+#define NETLINK_FSEVENT 17 /* File system events to userspace */
#define MAX_LINKS 32
--- a/include/linux/fsnotify.h.orig 2006-01-03 11:21:10.000000000 +0800
+++ b/include/linux/fsnotify.h 2006-04-03 22:12:52.000000000 +0800
@@ -15,6 +15,7 @@
#include <linux/dnotify.h>
#include <linux/inotify.h>
+#include <linux/fsevent.h>
/*
* fsnotify_move - file old_name at old_dir was moved to new_name at new_dir
@@ -45,6 +46,8 @@ static inline void fsnotify_move(struct
if (source) {
inotify_inode_queue_event(source, IN_MOVE_SELF, 0, NULL);
}
+ raise_fsevent_move(old_dir, old_name, new_dir, new_name,
+ FSEVENT_MOVE | (isdir?FSEVENT_ISDIR:0));
}
/*
@@ -56,6 +59,8 @@ static inline void fsnotify_nameremove(s
isdir = IN_ISDIR;
dnotify_parent(dentry, DN_DELETE);
inotify_dentry_parent_queue_event(dentry, IN_DELETE|isdir, 0, dentry->d_name.name);
+ raise_fsevent(dentry,
+ FSEVENT_DELETE | (isdir?FSEVENT_ISDIR:0));
}
/*
@@ -74,6 +79,7 @@ static inline void fsnotify_create(struc
{
inode_dir_notify(inode, DN_CREATE);
inotify_inode_queue_event(inode, IN_CREATE, 0, name);
+ raise_fsevent_create(inode, name, FSEVENT_CREATE);
}
/*
@@ -83,6 +89,8 @@ static inline void fsnotify_mkdir(struct
{
inode_dir_notify(inode, DN_CREATE);
inotify_inode_queue_event(inode, IN_CREATE | IN_ISDIR, 0, name);
+ raise_fsevent_create(inode, name,
+ FSEVENT_CREATE | FSEVENT_ISDIR);
}
/*
@@ -99,6 +107,8 @@ static inline void fsnotify_access(struc
dnotify_parent(dentry, DN_ACCESS);
inotify_dentry_parent_queue_event(dentry, mask, 0, dentry->d_name.name);
inotify_inode_queue_event(inode, mask, 0, NULL);
+ raise_fsevent(dentry, FSEVENT_ACCESS |
+ ((S_ISDIR(inode->i_mode))?FSEVENT_ISDIR:0));
}
/*
@@ -115,6 +125,8 @@ static inline void fsnotify_modify(struc
dnotify_parent(dentry, DN_MODIFY);
inotify_dentry_parent_queue_event(dentry, mask, 0, dentry->d_name.name);
inotify_inode_queue_event(inode, mask, 0, NULL);
+ raise_fsevent(dentry, FSEVENT_MODIFY |
+ ((S_ISDIR(inode->i_mode))?FSEVENT_ISDIR:0));
}
/*
@@ -130,6 +142,9 @@ static inline void fsnotify_open(struct
inotify_dentry_parent_queue_event(dentry, mask, 0, dentry->d_name.name);
inotify_inode_queue_event(inode, mask, 0, NULL);
+ raise_fsevent(dentry, FSEVENT_OPEN |
+ ((S_ISDIR(inode->i_mode))?FSEVENT_ISDIR:0));
+
}
/*
@@ -148,6 +163,8 @@ static inline void fsnotify_close(struct
inotify_dentry_parent_queue_event(dentry, mask, 0, name);
inotify_inode_queue_event(inode, mask, 0, NULL);
+ raise_fsevent(dentry, FSEVENT_CLOSE |
+ ((S_ISDIR(inode->i_mode))?FSEVENT_ISDIR:0));
}
/*
@@ -163,6 +180,8 @@ static inline void fsnotify_xattr(struct
inotify_dentry_parent_queue_event(dentry, mask, 0, dentry->d_name.name);
inotify_inode_queue_event(inode, mask, 0, NULL);
+ raise_fsevent(dentry, FSEVENT_MODIFY_ATTRIB |
+ ((S_ISDIR(inode->i_mode))?FSEVENT_ISDIR:0));
}
/*
@@ -213,6 +232,24 @@ static inline void fsnotify_change(struc
inotify_dentry_parent_queue_event(dentry, in_mask, 0,
dentry->d_name.name);
}
+
+#ifdef CONFIG_FS_EVENTS
+ {
+ u32 fsevent_mask = 0;
+ if (ia_valid & (ATTR_UID | ATTR_GID | ATTR_MODE))
+ fsevent_mask |= FSEVENT_MODIFY_ATTRIB;
+ if ((ia_valid & ATTR_ATIME) && (ia_valid & ATTR_MTIME))
+ fsevent_mask |= FSEVENT_MODIFY_ATTRIB;
+ else if (ia_valid & ATTR_ATIME)
+ fsevent_mask |= FSEVENT_ACCESS;
+ else if (ia_valid & ATTR_MTIME)
+ fsevent_mask |= FSEVENT_MODIFY;
+ if (ia_valid & ATTR_SIZE)
+ fsevent_mask |= FSEVENT_MODIFY;
+ if (fsevent_mask)
+ raise_fsevent(dentry, fsevent_mask);
+ }
+#endif /* CONFIG_FS_EVENTS */
}
#ifdef CONFIG_INOTIFY /* inotify helpers */
--- a/fs/namespace.c.orig 2006-03-25 23:13:42.000000000 +0800
+++ b/fs/namespace.c 2006-04-03 22:12:52.000000000 +0800
@@ -25,6 +25,7 @@
#include <linux/mount.h>
#include <asm/uaccess.h>
#include <asm/unistd.h>
+#include <linux/fsevent.h>
#include "pnode.h"
extern int __init init_rootfs(void);
@@ -612,6 +613,13 @@ asmlinkage long sys_umount(char __user *
goto dput_and_out;
retval = do_umount(nd.mnt, flags);
+
+ if (retval == 0) {
+ char * tmp = getname(name);
+ raise_fsevent_umount(tmp);
+ putname(tmp);
+ }
+
dput_and_out:
path_release_on_umount(&nd);
out:
@@ -1459,6 +1467,10 @@ asmlinkage long sys_mount(char __user *
retval = do_mount((char *)dev_page, dir_page, (char *)type_page,
flags, (void *)data_page);
unlock_kernel();
+
+ if (retval == 0)
+ raise_fsevent_mount((char *)dev_page, dir_page);
+
free_page(data_page);
out3:
--- a/fs/Kconfig.orig 2006-03-31 21:23:20.000000000 +0800
+++ b/fs/Kconfig 2006-04-03 22:12:52.000000000 +0800
@@ -405,6 +405,16 @@ config INOTIFY
If unsure, say Y.
+config FS_EVENTS
+ tristate "Report filesystem events to userspace"
+ ---help---
+ Provide a facility that reports filesystem events to userspace. The
+ reported event include access, write, utime, chmod, chown, chgrp,
+ close, open, create, rename, unlink, mkdir, rmdir, mount, umount.
+
+ The user can set filesystem events filter to filter its events, so
+ that he just get those events he concerns.
+
config QUOTA
bool "Quota support"
help
--- a/fs/Makefile.orig 2006-03-31 21:23:33.000000000 +0800
+++ b/fs/Makefile 2006-04-03 22:12:52.000000000 +0800
@@ -13,6 +13,7 @@ obj-y := open.o read_write.o file_table.
ioprio.o pnode.o drop_caches.o
obj-$(CONFIG_INOTIFY) += inotify.o
+obj-$(CONFIG_FS_EVENTS) += fsevent.o
obj-$(CONFIG_EPOLL) += eventpoll.o
obj-$(CONFIG_COMPAT) += compat.o compat_ioctl.o
--- /dev/null 2003-01-30 18:24:37.000000000 +0800
+++ b/include/linux/fsevent.h 2006-04-04 23:18:01.000000000 +0800
@@ -0,0 +1,131 @@
+/*
+ * fsevent.h - filesystem events connector
+ *
+ * Copyright (C) 2006 Yi Yang <[email protected]>
+ * Based on cn_proc.h by Matt Helsley, IBM Corp
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#ifndef LINUX_FSEVENT_H
+#define LINUX_FSEVENT_H
+
+#include <linux/types.h>
+#include <linux/time.h>
+#include <linux/netlink.h>
+
+enum fsevent_type {
+ FSEVENT_ACCESS = 0x00000001, /* File was accessed */
+ FSEVENT_MODIFY = 0x00000002, /* File was modified */
+ FSEVENT_MODIFY_ATTRIB = 0x00000004, /* Metadata changed */
+ FSEVENT_CLOSE = 0x00000008, /* File was closed */
+ FSEVENT_OPEN = 0x00000010, /* File was opened */
+ FSEVENT_MOVE = 0x00000020, /* File was moved */
+ FSEVENT_CREATE = 0x00000040, /* File was created */
+ FSEVENT_DELETE = 0x00000080, /* File was deleted */
+ FSEVENT_MOUNT = 0x00000100, /* File system is mounted */
+ FSEVENT_UMOUNT = 0x00000200, /* File system is umounted */
+
+ /* The following definitions are command types for fsevent filter
+ * or acknowlege types of the corresponding commands
+ */
+ FSEVENT_FILTER_ALL = 0x08000000, /* For all events */
+ FSEVENT_FILTER_PID = 0x10000000, /* For some process ID */
+ FSEVENT_FILTER_UID = 0x20000000, /* For some user ID */
+ FSEVENT_FILTER_GID = 0x40000000, /* For some group ID */
+
+ FSEVENT_ISDIR = 0x80000000 /* It is set for a dir */
+};
+
+#define FSEVENT_MASK 0x800003ff
+
+typedef unsigned long fsevent_mask_t;
+
+enum filter_control {
+ FSEVENT_FILTER_LISTEN = 1, /* Listen fsevents mask defines*/
+ FSEVENT_FILTER_IGNORE , /* Ignore fsevents mask defines*/
+ FSEVENT_FILTER_REMOVE, /* Remove a given filter */
+};
+
+struct fsevent_filter {
+ /* filter type, it just is one of them
+ * FSEVENT_FILTER_ALL
+ * FSEVENT_FILTER_PID
+ * FSEVENT_FILTER_UID
+ * FSEVENT_FILTER_GID
+ */
+ enum fsevent_type type; /* filter type */
+
+ /* mask of file system events the user listen or ignore
+ * if the user need to ignore all the events of some pid
+ * , gid or uid, he(she) must set mask to FSEVENT_MASK.
+ */
+ fsevent_mask_t mask;
+ union {
+ pid_t pid;
+ uid_t uid;
+ gid_t gid;
+ } id;
+
+ enum filter_control control;
+};
+
+struct fsevent {
+ __u32 type;
+ __u32 cpu;
+ struct timespec timestamp;
+ pid_t pid;
+ uid_t uid;
+ gid_t gid;
+ int err;
+ __u32 len;
+ __u32 pname_len;
+ __u32 fname_len;
+ __u32 new_fname_len;
+ char name[0];
+};
+
+#define FSEVENT_FILTER_MSGSIZE \
+ (sizeof(struct fsevent_filter) + sizeof(struct nlmsghdr))
+
+#ifdef __KERNEL__
+#ifdef CONFIG_FS_EVENTS
+extern void raise_fsevent(struct dentry * dentryp, u32 mask);
+extern void raise_fsevent_move(struct inode * olddir, const char * oldname,
+ struct inode * newdir, const char * newname, u32 mask);
+extern void raise_fsevent_create(struct inode * inode,
+ const char * name, u32 mask);
+extern void raise_fsevent_mount(const char * devname, const char * mountpoint);
+extern void raise_fsevent_umount(const char * mountpoint);
+#else
+static void raise_fsevent(struct dentry * dentryp, u32 mask)
+{}
+
+static void raise_fsevent_move(struct inode * olddir, const char * oldname,
+ struct inode * newdir, const char * newname, u32 mask)
+{}
+
+static void raise_fsevent_create(struct inode * inode,
+ const char * name, u32 mask)
+{}
+
+static void raise_fsevent_mount(const char * devname, const char * mountpoint)
+{}
+
+static void raise_fsevent_umount(const char * mountpoint)
+{}
+#endif /* CONFIG_FS_EVENTS */
+#endif /* __KERNEL__ */
+#endif /* LINUX_FSEVENT_H */
--- /dev/null 2003-01-30 18:24:37.000000000 +0800
+++ b/fs/fsevent.c 2006-04-05 20:52:53.000000000 +0800
@@ -0,0 +1,598 @@
+/*
+ * fsevent.c
+ *
+ * 2006 Copyright (c) Yi Yang <[email protected]>
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/netlink.h>
+#include <linux/moduleparam.h>
+#include <linux/fsevent.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <linux/list.h>
+#include <linux/percpu.h>
+#include <linux/cpu.h>
+#include <linux/kthread.h>
+#include <linux/notifier.h>
+#include <linux/compiler.h>
+#include <linux/workqueue.h>
+#include <linux/sysctl.h>
+
+#define FSEVENT_MASK_CTL_NAME -2
+
+static DEFINE_PER_CPU(struct sk_buff_head, fsevent_send_queue);
+static DEFINE_PER_CPU(struct work_struct, fsevent_work);
+
+typedef struct pid_filter {
+ pid_t pid;
+ u32 mask;
+ struct list_head list;
+} pid_filter;
+
+typedef struct uid_filter {
+ uid_t uid;
+ u32 mask;
+ struct list_head list;
+} uid_filter;
+
+typedef struct gid_filter {
+ gid_t gid;
+ u32 mask;
+ struct list_head list;
+} gid_filter;
+
+typedef struct fsevent_listener {
+ pid_t pid;
+ struct list_head pid_filter_list_head;
+ struct list_head uid_filter_list_head;
+ struct list_head gid_filter_list_head;
+ u32 mask;
+ struct list_head list;
+} listener;
+
+
+/* The netlink socket. */
+static struct sock * fsevent_sock = NULL;
+static LIST_HEAD(listener_list_head);
+static DEFINE_SPINLOCK(listener_list_lock);
+
+static atomic_t fsevent_count = ATOMIC_INIT(0);
+static int fsevent_burst_limit = 100;
+static int fsevent_ratelimit = 5 * HZ;
+static unsigned long last = 0;
+static int fsevent_sum = 0;
+static u32 fsevents_mask = FSEVENT_MASK;
+static atomic_t fsevent_listener_num = ATOMIC_INIT(0);
+
+static inline void get_seq(__u32 *ts, int *cpu)
+{
+ *ts = atomic_inc_return(&fsevent_count);
+ *cpu = smp_processor_id();
+}
+
+static void append_string(char **dest, const char *src, size_t len)
+{
+ strncpy(*dest, src, len);
+ (*dest)[len] = '\0';
+ *dest += len + 1;
+}
+
+static inline int filter_fsevent(u32 filter_mask, u32 event_mask)
+{
+ event_mask &= FSEVENT_MASK;
+ event_mask &= filter_mask;
+ if (event_mask == 0) {
+ return -1;
+ }
+ return 0;
+}
+
+static int filter_fsevent_all(u32 * mask)
+{
+ int ret = 0;
+
+ (*mask) &= FSEVENT_MASK;
+
+ if ((((*mask) & FSEVENT_ISDIR) == FSEVENT_ISDIR)
+ && ((fsevents_mask & FSEVENT_ISDIR) == 0)) {
+ ret = -1;
+ goto out;
+ }
+
+ (*mask) &= fsevents_mask;
+ if ((*mask) == 0) {
+ ret = -5;
+ }
+
+out:
+ return ret;
+}
+
+static void fsevent_send(struct sk_buff * skb)
+{
+ struct sk_buff_head * head = &get_cpu_var(fsevent_send_queue);
+ skb_queue_tail(head, skb);
+ schedule_work(&per_cpu(fsevent_work, smp_processor_id()));
+ put_cpu_var(fsevent_send_queue);
+}
+
+int __raise_fsevent(const char * oldname, const char * newname, u32 mask)
+{
+ struct fsevent *event;
+ int namelen = 0;
+ char * nameptr = NULL;
+ unsigned int size;
+ struct nlmsghdr * nlhdr;
+ struct sk_buff * skb = NULL;
+
+ if (filter_fsevent_all(&mask) != 0)
+ return -1;
+
+ if (atomic_read(&fsevent_listener_num) <= 0)
+ return -1;
+
+ if (jiffies - last <= fsevent_ratelimit) {
+ if (fsevent_sum > fsevent_burst_limit)
+ return -2;
+ fsevent_sum++;
+ } else {
+ last = jiffies;
+ fsevent_sum = 0;
+ }
+
+ namelen = strlen(current->comm) + strlen(oldname) + 2;
+ if (newname)
+ namelen += strlen(newname) + 1;
+
+ size = NLMSG_SPACE(sizeof(struct fsevent) + namelen);
+
+ skb = alloc_skb(size, GFP_KERNEL);
+ if (!skb)
+ return -ENOMEM;
+
+ nlhdr = NLMSG_PUT(skb, 0, 0, NLMSG_DONE, size - sizeof(*nlhdr));
+ event = NLMSG_DATA(nlhdr);
+
+ get_seq(&(nlhdr->nlmsg_seq), &event->cpu);
+ ktime_get_ts(&event->timestamp);
+ event->type = mask;
+ event->pid = current->tgid;
+ event->uid = current->uid;
+ event->gid = current->gid;
+ nameptr = event->name;
+ event->pname_len = strlen(current->comm);
+ append_string(&nameptr, current->comm, event->pname_len);
+ event->fname_len = strlen(oldname);
+ append_string(&nameptr, oldname, event->fname_len);
+ event->len = event->pname_len + event->fname_len + 2;
+ event->new_fname_len = 0;
+ if (newname) {
+ event->new_fname_len = strlen(newname);
+ append_string(&nameptr, newname, event->new_fname_len);
+ event->len += event->new_fname_len + 1;
+ }
+ fsevent_send(skb);
+ return 0;
+
+nlmsg_failure:
+ kfree_skb(skb);
+ return -1;
+}
+
+void raise_fsevent(struct dentry * dentryp, u32 mask)
+{
+ if (dentryp->d_inode && (MAJOR(dentryp->d_inode->i_rdev) == 4))
+ return;
+ __raise_fsevent(dentryp->d_name.name, NULL, mask);
+}
+EXPORT_SYMBOL_GPL(raise_fsevent);
+
+void raise_fsevent_create(struct inode * inode, const char * name, u32 mask)
+{
+ __raise_fsevent(name, NULL, mask);
+}
+EXPORT_SYMBOL_GPL(raise_fsevent_create);
+
+void raise_fsevent_move(struct inode * olddir, const char * oldname,
+ struct inode * newdir, const char * newname, u32 mask)
+{
+ __raise_fsevent(oldname, newname, mask);
+}
+EXPORT_SYMBOL_GPL(raise_fsevent_move);
+
+void raise_fsevent_mount(const char * devname, const char * mountpoint)
+{
+ __raise_fsevent(devname, mountpoint, FSEVENT_MOUNT);
+}
+
+void raise_fsevent_umount(const char * mountpoint)
+{
+ __raise_fsevent(mountpoint, NULL, FSEVENT_UMOUNT);
+}
+
+static int fsevent_ack(enum fsevent_type type, pid_t pid, u32 seq)
+{
+ struct fsevent *event;
+ unsigned int size;
+ struct sk_buff * skb = NULL;
+ struct nlmsghdr * nlhdr = NULL;
+
+ size = NLMSG_SPACE(sizeof(struct fsevent));
+
+ skb = alloc_skb(size, GFP_KERNEL);
+ if (!skb)
+ return -ENOMEM;
+
+ nlhdr = NLMSG_PUT(skb, 0, seq, NLMSG_DONE, size - sizeof(*nlhdr));
+ event = NLMSG_DATA(nlhdr);
+
+ ktime_get_ts(&event->timestamp);
+ event->cpu = -1;
+ event->type = type;
+ event->pid = 0;
+ event->uid = 0;
+ event->gid = 0;
+ event->len = 0;
+ event->pname_len = 0;
+ event->fname_len = 0;
+ event->new_fname_len = 0;
+ event->err = 0;
+
+ NETLINK_CB(skb).dst_group = 0;
+ NETLINK_CB(skb).dst_pid = pid;
+ NETLINK_CB(skb).pid = 0;
+
+ return (netlink_unicast(fsevent_sock, skb, pid, MSG_DONTWAIT));
+
+nlmsg_failure:
+ kfree_skb(skb);
+ return -1;
+}
+
+static void set_fsevent_mask(u32 * to_mask, u32 from_mask, int mode)
+{
+ if (mode == FSEVENT_FILTER_IGNORE)
+ (*to_mask) &= ~(from_mask);
+ else if (mode == FSEVENT_FILTER_LISTEN)
+ (*to_mask) |= from_mask;
+}
+
+#define DEFINE_FILTER_FIND_FUNC(type, key) \
+ type * find_##type(struct list_head * head, key##_t id) \
+ { \
+ int alloc_flag = 1; \
+ type * entry = NULL; \
+ \
+ list_for_each_entry(entry, head, list) { \
+ if (entry->key == id) { \
+ alloc_flag = 0; \
+ break; \
+ } \
+ } \
+ \
+ if (alloc_flag == 1) { \
+ entry = (type *)kmalloc(sizeof(type), GFP_ATOMIC); \
+ if (entry == NULL) \
+ return NULL; \
+ memset(entry, 0, sizeof(type)); \
+ entry->key = id; \
+ list_add_tail(&(entry->list), head); \
+ } \
+ return entry; \
+ } \
+
+DEFINE_FILTER_FIND_FUNC(pid_filter, pid)
+
+DEFINE_FILTER_FIND_FUNC(uid_filter, uid)
+
+DEFINE_FILTER_FIND_FUNC(gid_filter, gid)
+
+DEFINE_FILTER_FIND_FUNC(listener, pid)
+
+static void set_fsevent_filter(struct fsevent_filter * filter, pid_t pid)
+{
+ enum fsevent_type type;
+ u32 mask = 0;
+ int control = 0;
+ listener * listenerp = NULL;
+ pid_filter * pfilter = NULL;
+ uid_filter * ufilter = NULL;
+ gid_filter * gfilter = NULL;
+
+
+ mask = filter->mask;
+ control = filter->control;
+ type = filter->type;
+ mask &= FSEVENT_MASK;
+ if (mask == 0)
+ goto out;
+
+ spin_lock(&listener_list_lock);
+ listenerp = find_listener(&listener_list_head, pid);
+ if (unlikely(listenerp == NULL)) {
+ spin_unlock(&listener_list_lock);
+ return;
+ }
+
+ if (!(listenerp->pid_filter_list_head.next)) {
+ INIT_LIST_HEAD(&(listenerp->pid_filter_list_head));
+ INIT_LIST_HEAD(&(listenerp->uid_filter_list_head));
+ INIT_LIST_HEAD(&(listenerp->gid_filter_list_head));
+ }
+
+ if ((type & FSEVENT_FILTER_ALL) == FSEVENT_FILTER_ALL) {
+ if (control == FSEVENT_FILTER_REMOVE) {
+ atomic_dec(&fsevent_listener_num);
+ list_del(&(listenerp->list));
+ kfree(listenerp);
+ } else
+ set_fsevent_mask(&(listenerp->mask), mask, control);
+ } else if ((type & FSEVENT_FILTER_PID) == FSEVENT_FILTER_PID) {
+ pfilter = find_pid_filter(&(listenerp->pid_filter_list_head),
+ filter->id.pid);
+ if (unlikely(pfilter == NULL))
+ return;
+
+ if (control == FSEVENT_FILTER_REMOVE) {
+ list_del(&(pfilter->list));
+ kfree(pfilter);
+ } else
+ set_fsevent_mask(&(pfilter->mask), mask, control);
+ } else if ((type & FSEVENT_FILTER_UID) == FSEVENT_FILTER_UID) {
+ ufilter = find_uid_filter(&(listenerp->uid_filter_list_head),
+ filter->id.uid);
+ if (unlikely(ufilter == NULL))
+ return;
+
+ if (control == FSEVENT_FILTER_REMOVE) {
+ list_del(&(ufilter->list));
+ kfree(ufilter);
+ } else
+ set_fsevent_mask(&(ufilter->mask), mask, control);
+ } else if ((type & FSEVENT_FILTER_GID) == FSEVENT_FILTER_GID) {
+ gfilter = find_gid_filter(&(listenerp->gid_filter_list_head),
+ filter->id.gid);
+ if (unlikely(gfilter == NULL))
+ return;
+
+ if (control == FSEVENT_FILTER_REMOVE) {
+ list_del(&(gfilter->list));
+ kfree(gfilter);
+ } else
+ set_fsevent_mask(&(gfilter->mask), mask, control);
+ }
+ spin_unlock(&listener_list_lock);
+
+out:
+ fsevent_ack(type, pid, 0);
+}
+
+static listener * find_fsevent_listener(pid_t pid)
+{
+ listener * listenerp = NULL;
+ spin_lock(&listener_list_lock);
+ list_for_each_entry(listenerp, &listener_list_head, list) {
+ if (listenerp->pid == pid) {
+ spin_unlock(&listener_list_lock);
+ return listenerp;
+ }
+ }
+ spin_unlock(&listener_list_lock);
+ return NULL;
+}
+
+static void cleanup_dead_listener(listener * x)
+{
+ pid_filter * p = NULL, * pq = NULL;
+ uid_filter * u = NULL, * uq = NULL;
+ gid_filter * g = NULL, * gq = NULL;
+
+ if (p == NULL)
+ return;
+
+ list_del(&(x->list));
+
+ list_for_each_entry_safe(p, pq, &(x->pid_filter_list_head), list) {
+ list_del(&(p->list));
+ kfree(p);
+ }
+
+ list_for_each_entry_safe(u, uq, &(x->uid_filter_list_head), list) {
+ list_del(&(u->list));
+ kfree(u);
+ }
+
+ list_for_each_entry_safe(g, gq, &(x->gid_filter_list_head), list) {
+ list_del(&(g->list));
+ kfree(g);
+ }
+
+ kfree(x);
+}
+
+static void fsevent_recv(struct sock *sk, int len)
+{
+ struct sk_buff *skb = NULL;
+ struct nlmsghdr *nlhdr = NULL;
+ struct fsevent_filter * filter = NULL;
+ pid_t pid;
+
+ while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
+ skb_get(skb);
+ if (skb->len >= FSEVENT_FILTER_MSGSIZE) {
+ nlhdr = (struct nlmsghdr *)skb->data;
+ filter = NLMSG_DATA(nlhdr);
+ pid = NETLINK_CREDS(skb)->pid;
+ if (find_fsevent_listener(pid) == NULL)
+ atomic_inc(&fsevent_listener_num);
+ set_fsevent_filter(filter, pid);
+ }
+ kfree_skb(skb);
+ }
+}
+
+#define DEFINE_FILTER_MATCH_FUNC(filtertype, key) \
+ static int match_##filtertype(listener * p, \
+ struct fsevent * event, \
+ struct sk_buff * skb) \
+ { \
+ int ret = 0; \
+ filtertype * xfilter = NULL; \
+ struct sk_buff * skb2 = NULL; \
+ struct list_head * head = &(p->key##_filter_list_head); \
+ list_for_each_entry(xfilter, head, list) { \
+ if (xfilter->key != event->key) \
+ continue; \
+ ret = filter_fsevent(xfilter->mask, event->type); \
+ if ( ret != 0) \
+ return -1; \
+ skb2 = skb_clone(skb, GFP_KERNEL); \
+ if (skb2 == NULL) \
+ return -ENOMEM; \
+ NETLINK_CB(skb2).dst_group = 0; \
+ NETLINK_CB(skb2).dst_pid = p->pid; \
+ NETLINK_CB(skb2).pid = 0; \
+ return (netlink_unicast(fsevent_sock, skb2, \
+ p->pid, MSG_DONTWAIT)); \
+ } \
+ return -ENODEV; \
+ } \
+
+DEFINE_FILTER_MATCH_FUNC(pid_filter, pid)
+
+DEFINE_FILTER_MATCH_FUNC(uid_filter, uid)
+
+DEFINE_FILTER_MATCH_FUNC(gid_filter, gid)
+
+#define MATCH_XID(key, listenerp, event, skb) \
+ ret = match_##key##_filter(listenerp, event, skb); \
+ if (ret == 0) { \
+ kfree_skb(skb); \
+ continue; \
+ } \
+ do {} while (0) \
+
+static int fsevent_send_to_process(struct sk_buff * skb)
+{
+ listener * p = NULL, * q = NULL;
+ struct fsevent * event = NULL;
+ struct sk_buff * skb2 = NULL;
+ int ret = 0;
+
+ event = (struct fsevent *)(skb->data + sizeof(struct nlmsghdr));
+ spin_lock(&listener_list_lock);
+ list_for_each_entry_safe(p, q, &listener_list_head, list) {
+ MATCH_XID(pid, p, event, skb);
+ MATCH_XID(uid, p, event, skb);
+ MATCH_XID(gid, p, event, skb);
+
+ if (filter_fsevent(p->mask, event->type) == 0) {
+ skb2 = skb_clone(skb, GFP_KERNEL);
+ if (skb2 == NULL)
+ return -ENOMEM;
+ NETLINK_CB(skb2).dst_group = 0;
+ NETLINK_CB(skb2).dst_pid = p->pid;
+ NETLINK_CB(skb2).pid = 0;
+ ret = netlink_unicast(fsevent_sock, skb2,
+ p->pid, MSG_DONTWAIT);
+ if (ret == -ECONNREFUSED) {
+ atomic_dec(&fsevent_listener_num);
+ cleanup_dead_listener(p);
+ }
+ }
+ }
+ spin_unlock(&listener_list_lock);
+ return ret;
+}
+
+static void fsevent_commit(void * unused)
+{
+ struct sk_buff * skb = NULL;
+
+ while((skb = skb_dequeue(&get_cpu_var(fsevent_send_queue)))
+ != NULL) {
+ fsevent_send_to_process(skb);
+ put_cpu_var(fsevent_send_queue);
+ }
+}
+
+static struct ctl_table fsevent_mask_sysctl[] = {
+ {
+ .ctl_name = FSEVENT_MASK_CTL_NAME,
+ .procname = "fsevent_mask",
+ .data = &fsevents_mask,
+ .maxlen = sizeof(u32),
+ .mode = 0644,
+ .proc_handler = &proc_dointvec,
+ },
+ { .ctl_name = 0 }
+};
+
+static struct ctl_table fs_root_sysctl[] = {
+ {
+ .ctl_name = CTL_FS,
+ .procname = "fs",
+ .mode = 0555,
+ .child = fsevent_mask_sysctl,
+ },
+ { .ctl_name = 0 }
+};
+
+static int __init fsevent_init(void)
+{
+ int cpu;
+ struct sk_buff_head * listptr;
+ struct work_struct * workptr;
+
+ fsevent_sock = netlink_kernel_create(NETLINK_FSEVENT, 0,
+ fsevent_recv, THIS_MODULE);
+ if (!fsevent_sock)
+ return -EIO;
+ for_each_cpu(cpu) {
+ listptr = &per_cpu(fsevent_send_queue, cpu);
+ skb_queue_head_init(listptr);
+ workptr = &per_cpu(fsevent_work, cpu);
+ INIT_WORK(workptr, fsevent_commit, NULL);
+ }
+
+ if (register_sysctl_table(fs_root_sysctl, 0) == NULL)
+ return -ENOMEM;
+
+ return 0;
+}
+
+static void __exit fsevent_exit(void)
+{
+ listener * p = NULL, * q = NULL;
+ sock_release(fsevent_sock->sk_socket);
+ spin_lock(&listener_list_lock);
+ list_for_each_entry_safe(p, q, &listener_list_head, list) {
+ cleanup_dead_listener(p);
+ }
+ spin_unlock(&listener_list_lock);
+}
+
+module_init(fsevent_init);
+module_exit(fsevent_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Yi Yang <[email protected]>");
+MODULE_DESCRIPTION("File System Events Reporter");
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