Message-ID: <40CF9382.2010008@linux.jf.intel.com>
Date: Tue, 15 Jun 2004 17:25:38 -0700
From: Atul Sabharwal <atul_sabharwal@linux.jf.intel.com>
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To: linux-kernel@vger.kernel.org
CC: faith@redhat.com
Subject: Re: [Announce] Non Invasive Kernel Monitor for threads/processes
References: <40CF4233.70709@linux.jf.intel.com>	<40CF5D39.1060701@linux.jf.intel.com> <20040615142304.5d9591d5.akpm@osdl.org>
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Andrew Morton wrote:

>Atul Sabharwal <atul_sabharwal@linux.jf.intel.com> wrote:
>  
>
>> We have been working with a solution for non-intrusively trapping on 
>> lifetime
>> of processes/threads.
>>    
>>
>
>I expect this functionality can be provided without kernel changes via
>auditing of the relevant system calls.  See
>http://people.redhat.com/faith/audit/.
>
>Maybe there are shortcomings in the current auditing/filtering framework. 
>If so, perhaps they could be addressed.
>
>For you, the next step should be to send the patch and description (without
>wordwrapping this time, please) to linux-kernel, and cc Rik Faith
><faith@redhat.com>, see what Rik and the SELinux guys have to say about it.
>

Hi Rick,

I have attached the description and patch about the non-invasive kernel 
monitor. Looking
for comments/feedback from you about the differences/value add between 
the two solutions ?

Thanks,

Atul

>I have been experimenting with the CGL 2.0 AVL 8.2 requirement on Non-intrusive kernel
>based monitoring of processes and threads.  For your reference, the requirement is
>quoted below :
>
>AVL 8.2 requirement :
>~~~~~~~~~~~~~~~~~~~~~
>CGL shall support methods to non-intrusively monitor processes at the kernel level.
>It would use a notfication mechanism in the kernel that allows registration of events
>of interest regarding processes. Events of interest could be the following :
>Process creation (fork), Process exit ( exit ), Process calls ( exec ), thread
>creation & thread exit. 
>
>The implementation needs to provide high performance with low overhead. Monitoring
>would be driven directly by the events in the kernel to ensure low latency access
>to interesting events. 
>
>Solution Approach:
>~~~~~~~~~~~~~~~~~~
>This method requires a user space process (called monitor) to start and stop 
>monitoring in the system.  The monitor sends the list of pids and the events 
>to be monitored for that pid. Once the ioctl is received, the kernel establishes
>a filter for it.  Events get flooded in the system as each call (fork, exec and
> exit) has been modified to generate events. The events which match the filter 
>become interesting and require that a notification is sent to the monitor process.
>Events which do no match the filter get dropped. 
>
>In the case when we have multiple monitor processes, signals are sent to each monitor 
>whose filters match the event which has occurred.
>
>
>Solution Description :
>~~~~~~~~~~~~~~~~~~~~~~
>The registration and de-registration command are implemented as ioctls. The notification
>command is implemented as a sigqueue signal. The system calls such as fork, exit, and 
>exec have been changed to add a notification call to the monitor process.  The filter 
>for events is populated with the registration command. Events & their respective 
>thread/process get removed from the filter with the de-registration command.
>
>Threads and processes follow the same code path for task creation and termination. 
>Hence, the code path is the same for threads and processes. There is no equivalent
>of an exec call with threads.  The only distinction for a thread is that in the 
>task struct, the thread group id (tgid) and process id (pid) are different. For 
>a process, they are the same.  
>
>The signal used for notification is also specified with the registration command. 
>If it is a real-time signal, it would perform better as signals would get queued 
>for the monitor. With non-real time signals, signals would get dropped if one 
>signal exists. Hence, it is recommended to specify a real time signal. 
>
>Also, it is to be noted that the solution is totally architecture independent.  
>So, would just need a re-compile on the respective platform.
>
>Kmonitor has been implemented as a miscellaneous character driver built into the 
>Linux kernel. It cannot be compiled as a loadable module.  It supports the relevant
>driver calls for open, release, ioctl, init, cleanup calls.  The character driver 
>code contains the filtering, registration/de-registration and notification functions
>of Kmonitor as wells as routines to manage the linked list(s) for filtering.
>
>Kmonitor has 256 buckets and each bucket contains a spinlock and a linked list. 
>This works around the sequential search operation in linked list by using a 
>hashing function to change the complexity from O(N) to O(N/M) where M is the 
>number of buckets.
>
>Kernel Version & Code location:
>~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>The kernel used was the 2.6.6 kernel and the code is at http://kmonitor.bkbits.net
>
>
>User space programs:
>~~~~~~~~~~~~~~~~~~~~
>1. unit_test : A sample program to monitor future processes.
>     http://kmonitor.bkbits.net:8080/tools/anno/unit_test.c@1.4?nav=index.html|ChangeSet@-3w|cset@1.35
>
>2. monitor_pid: A sample program to monitor a process sub-tree.
>     http://kmonitor.bkbits.net:8080/tools/anno/monitor_pid.c@1.2?nav=index.html|ChangeSet@-2w|cset@1.37
>
>3. wait_on_pid : A sample program which waits till a pid dies.
>     http://kmonitor.bkbits.net:8080/tools/anno/wait_on_pid.c@1.5?nav=index.html|ChangeSet@-2w|cset@1.37
>
>Source Code:
>~~~~~~~~~~~~
>The patch for Kmonitor is as below :
>
>
>diff -Nru a/Documentation/ioctl-number.txt b/Documentation/ioctl-number.txt
>--- a/Documentation/ioctl-number.txt	2004-06-14 11:24:08 -07:00
>+++ b/Documentation/ioctl-number.txt	2004-06-14 11:24:08 -07:00
>@@ -189,3 +189,4 @@
> 					<mailto:michael.klein@puffin.lb.shuttle.de>
> 0xDD	00-3F	ZFCP device driver	see drivers/s390/scsi/
> 					<mailto:aherrman@de.ibm.com>
>+0xDE	all	drivers/char/kmonitor	<mailto:atul.sabharwal@intel.com>
>diff -Nru a/Documentation/kmonitor.txt b/Documentation/kmonitor.txt
>--- /dev/null	Wed Dec 31 16:00:00 196900
>+++ b/Documentation/kmonitor.txt	2004-06-14 11:24:08 -07:00
>@@ -0,0 +1,119 @@
>+Enabling Non-intrusive Application Monitoring with kmonitor
>+-----------------------------------------------------------
>+The kmonitor driver implements a kernel level non-intrusive 
>+mechanism for rapidly notifying a monitoring user space process
>+of key (process/thread creation/exit) kernel events.
>+
>+The monitoring user space process registers and deregisters for events via
>+a new misc char device using two new ioctl's.  The kernel notifies the
>+monitoring process(es) of the events via a signal that the monitor specifies
>+during registration.
>+
>+An example of how this would be used in an minimal command line utility
>+to wait for an arbitrary process to exit:
>+
>+<snip>rest of required headers...</snip>
>+#include <linux/kmonitor.h>
>+
>+void target_exit_handler (int signum , struct siginfo * info, void * buf)
>+{
>+	 /*
>+	  * Since we only registered for one type of event,
>+	  * KMONITOR_PROCESS_EXIT, on one process, then we already 
>+	  * know our target process has exited
>+	  *
>+	  * If we were doing something more complex, then the data in
>+	  * info might be usefull:
>+	  * 1. info->si_pid: process id of target process
>+	  * 2. info->si_gid: group id of target process
>+	  * 3. info->si_int: event that triggered this signal
>+	  *    (See include/linux/kmonitor.h for the list of events)
>+	  *
>+	  * The target process has exited, so we are done. Kmonitor
>+	  * will do cleanup when we close the file descriptor for 
>+	  * /dev/kmonitor (which will happen automatically when we
>+	  * exit.)
>+	  */
>+	exit(0);
>+}
>+
>+int main(int argc, char *argv[])
>+{
>+<snip>...</snip>
>+
>+	/*
>+	 * kmonitor will notify us that the target process has exited
>+	 * by sending us a real-time signal with the payload containing
>+	 * the event that triggered the notification.
>+	 */
>+	action.sa_sigaction = target_exit_handler;
>+	action.sa_flags = SA_SIGINFO;
>+	if (-1 == sigaction(SIGRTMIN, &action, NULL)) {
>+		perror("sigaction");
>+		exit(-1);
>+	}
>+
>+	/*
>+	 * The kmonitor is implemented as misc char device, so the
>+	 * file that needs to be opened (assumed to be /dev/kmonitor
>+	 * in this example) is a char device with a major number of 10
>+	 * and a minor number of 221.
>+	 * 
>+	 * mknod /dev/kmonitor c 10 221 
>+	 */
>+	fd = open("/dev/kmonitor", O_WRONLY);
>+	if (-1 == fd) {
>+		perror("open /dev/kmonitor");
>+		exit(-1);
>+	}
>+
>+	/*
>+	 * To sign up for notification of an arbitrary event on an
>+	 * arbitrary process then we send the KMONITOR_IOW_REGISTER
>+	 * command to the device via the ioctl system call.
>+	 *
>+	 * We indicate the target process and event by sending a
>+	 * kmonitor_cmd structure.
>+	 *
>+	 * NOTE: The 'type' field in the structure is actually 
>+	 *       a bitmask, so it is possible to register for
>+	 *       multiple events on a given target process in one
>+	 *       ioctl call.  The possible events are...
>+         *       #define KMONITOR_THREAD_CREATE 0x01 
>+         *       #define KMONITOR_THREAD_ABORT  0x02           
>+         *       #define KMONITOR_THREAD_EXIT   0x04
>+         *       #define KMONITOR_PROCESS_FORK  0x08
>+         *       #define KMONITOR_PROCESS_ABORT 0x10 
>+         *       #define KMONITOR_PROCESS_EXEC  0x20 
>+         *       #define KMONITOR_PROCESS_EXIT  0x40
>+	 */
>+	hdr.signal = SIGRTMIN;
>+	hdr.pid = args.pid;
>+	hdr.type = KMONITOR_PROCESS_EXIT;
>+	if (-1 == ioctl(fd, KMONITOR_IOW_REGISTER, &hdr)) {
>+		perror("ioctl");
>+		exit(-1);
>+	}
>+	
>+	/*
>+	 * In this very simple example all we need to do is wait 
>+	 * for a signal to be sent.  The signal handler will exit
>+	 * when it is notified of the target process exiting.
>+	 */
>+	sigemptyset(&empty_mask);
>+	sigsuspend(&empty_mask);	
>+
>+	/*
>+	 * kmonitor will perform a cleanup of all request a given 
>+	 * monitoring process has made, so it is required to deregister
>+	 * each of the specific request.
>+	 *
>+	 * If for some reason a monitoring process wanted to deregister
>+	 * a specific request, then the procedure is just like registering,
>+	 * other then the ioctl command is KMONITOR_IOW_DEREGISTER.
>+	 */
>+	close(fd);
>+	exit (0);
>+}
>+
>+
>diff -Nru a/drivers/char/Kconfig b/drivers/char/Kconfig
>--- a/drivers/char/Kconfig	2004-06-14 11:24:08 -07:00
>+++ b/drivers/char/Kconfig	2004-06-14 11:24:08 -07:00
>@@ -974,5 +974,15 @@
> 	  out to lunch past a certain margin.  It can reboot the system
> 	  or merely print a warning.
> 
>+config KMONITOR
>+	bool "Kmonitor driver"
>+	help
>+	  The kmonitor driver implements a kernel level non-intrusive 
>+	  mechanism for rapidly notifying a monitoring user space process
>+	  of key (process/thread creation/exit) kernel events. For more
>+	  info see Documentation/kmonitor.txt 
>+
>+	  If in doubt, say 'N'.
>+
> endmenu
> 
>diff -Nru a/drivers/char/Makefile b/drivers/char/Makefile
>--- a/drivers/char/Makefile	2004-06-14 11:24:08 -07:00
>+++ b/drivers/char/Makefile	2004-06-14 11:24:08 -07:00
>@@ -79,6 +79,7 @@
> obj-$(CONFIG_DRM) += drm/
> obj-$(CONFIG_PCMCIA) += pcmcia/
> obj-$(CONFIG_IPMI_HANDLER) += ipmi/
>+obj-$(CONFIG_KMONITOR) += kmonitor.o
> 
> obj-$(CONFIG_HANGCHECK_TIMER) += hangcheck-timer.o
> 
>diff -Nru a/drivers/char/kmonitor.c b/drivers/char/kmonitor.c
>--- /dev/null	Wed Dec 31 16:00:00 196900
>+++ b/drivers/char/kmonitor.c	2004-06-14 11:24:08 -07:00
>@@ -0,0 +1,336 @@
>+/*
>+ * linux/kmonitor.c
>+ *
>+ * Copyright (C)  2004 Intel Corporation.  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 v2.0 as published by the Free Software Foundation; 
>+ *
>+ * 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 021110-1307, USA.
>+ *
>+ * Authors: Atul Sabharwal <atul.sabharwal@intel.com>
>+ *
>+ * The kmonitor driver implements a kernel level non-intrusive 
>+ * mechanism for rapidly notifying a monitoring user space process
>+ * of key (process/thread creation/exit) kernel events.
>+ * 
>+ * See Documentation/kmonitor.txt for more details
>+ */
>+
>+#include <linux/config.h>
>+#include <linux/module.h>
>+#include <linux/moduleparam.h>
>+#include <linux/fs.h>
>+#include <linux/hash.h>
>+#include <linux/init.h>
>+#include <linux/kmonitor.h>
>+#include <linux/miscdevice.h>
>+#include <linux/proc_fs.h>
>+#include <linux/sched.h>
>+#include <linux/types.h>
>+#include <linux/timer.h>
>+#include <asm/uaccess.h>
>+#include <asm/atomic.h>
>+
>+/*
>+ * kmonitor maintains a database of resources containing:
>+ * - the pid of the process being monitored (target)
>+ * - the pid of process that should be notified (monitor)
>+ * - an event mask 
>+ * - a signal number to notify the monitor with
>+ * - a list_head
>+ * 
>+ * To improve scalability, a hash of linked listed is maintained
>+ * with a per bucket read-write lock.  KMONITOR_BITS defines the
>+ * order of the list size, so setting KMONITOR_BITS to 8 would translate
>+ * to 256 buckets.  Using a hash of linked list improves the order of the
>+ * search from an O(n) to O(n/m) where n is the number of resources and
>+ * m is the number of buckets.
>+ *
>+ * Note that since we are using a per bucket read-write lock, the number
>+ * of buckets also as an effect on SMP performance since the smaller the
>+ * list of resources in each bucket, the less likely a processor will 
>+ * spin waiting for another processor to finish writing to the same list.
>+ */
>+
>+struct kmonitor_bucket 
>+{
>+	struct list_head list;
>+	rwlock_t lock;
>+};
>+
>+#define KMONITOR_BITS 0x8
>+
>+struct kmonitor_bucket kmonitor_resources[1<<KMONITOR_BITS];
>+
>+static inline unsigned long khash(pid_t target)
>+{
>+	return hash_long((unsigned long)target, KMONITOR_BITS);
>+}
>+
>+struct kmonitor_res
>+{
>+	struct list_head rlist;
>+	pid_t target;
>+	pid_t monitor;
>+	int signal;
>+	__u32 event_mask;
>+};
>+
>+#define to_kmonitor_res(r) \
>+        container_of(r, struct kmonitor_res, rlist);
>+
>+kmem_cache_t *kmonitor_cache;
>+
>+/*
>+ * kmonitor_active is used to improve the performance of searching
>+ * an empty resource database
>+ */
>+atomic_t kmonitor_active = { .counter = 0};
>+
>+/* #define DEBUG */
>+#ifdef DEBUG
>+#define DBG(format, arg...) printk("%s: " format "\n", __FUNCTION__ , ## arg)
>+#define TRACE(format, arg...) printk("%s(" format ")\n", __FUNCTION__, ## arg)
>+#else
>+#define DBG(format, arg...) do {} while(0);
>+#define TRACE(arg...) do {} while(0);
>+#endif
>+
>+static int kmonitor_add(pid_t target, int type, int signal)
>+{
>+	struct kmonitor_res *r;
>+	struct list_head *tmp;
>+	unsigned long bucket = khash(target);
>+
>+	TRACE("%i, %i, %i", target, type, signal);
>+	read_lock(&kmonitor_resources[bucket].lock);
>+	list_for_each(tmp, &kmonitor_resources[bucket].list) {
>+		r = to_kmonitor_res(tmp);
>+		if (r->monitor == current->pid && r->target == target) {
>+			/*
>+			 * There is an existing resource for this
>+			 * target/monitor combination so just flip 
>+			 * a bit in the event mask indicating that 
>+			 * this monitor also wants to be notified 
>+			 * for this type of event.
>+			 */
>+			r->event_mask |= type;
>+			r->signal = signal;
>+			DBG("Added %i to existing res", type);
>+			read_unlock(&kmonitor_resources[bucket].lock);
>+			return 0;
>+		} 
>+	}
>+	read_unlock(&kmonitor_resources[bucket].lock);
>+
>+	/*
>+	 * This is the first event registered for this target 
>+	 * on this monitor.  Allocate a new resource from our 
>+	 * cache and add the resource to the global list.
>+	 *
>+         * Note: There is no race condition between the top half & the
>+         * bottom part of this function as if multiple monitors are active,
>+         * each will have a unique resource for itself. So, the function
>+         * is SMP safe.
>+         */
>+	r = kmem_cache_alloc(kmonitor_cache, SLAB_KERNEL);
>+	if (!r)
>+		return -ENOMEM;
>+		
>+	r->target = target;
>+	r->monitor = current->pid;
>+	r->event_mask = type;
>+	r->signal = signal;
>+	write_lock(&kmonitor_resources[bucket].lock);
>+	list_add(&r->rlist, &kmonitor_resources[bucket].list);
>+	write_unlock(&kmonitor_resources[bucket].lock);
>+	return 0;
>+}
>+
>+static int kmonitor_remove(pid_t target, int type)
>+{
>+	struct list_head *tmp, *next;
>+	int ret = -EINVAL;
>+	int bucket = khash(target);
>+
>+	TRACE("%i, %i", target, type);
>+
>+	write_lock(&kmonitor_resources[bucket].lock);
>+	list_for_each_safe(tmp, next, &kmonitor_resources[bucket].list) {
>+		struct kmonitor_res *r = to_kmonitor_res(tmp);
>+		if (r->monitor == current->pid && r->target == target) {
>+			r->event_mask &= ~type;
>+			if (!r->event_mask) {
>+				/* No more events so go ahead and cleanup */
>+				list_del(tmp);
>+				kmem_cache_free(kmonitor_cache, r);
>+			}
>+			ret = 0;
>+			break;
>+		} 
>+	}
>+
>+	write_unlock(&kmonitor_resources[bucket].lock);
>+	return ret;
>+}
>+
>+void __kmonitor_notify_event(struct task_struct *tsk, int type) 
>+{
>+	struct siginfo info;
>+	struct list_head *tmp, *next;
>+	int bucket = khash(current->pid);
>+
>+	read_lock(&kmonitor_resources[bucket].lock);
>+	list_for_each_safe(tmp,next,&kmonitor_resources[bucket].list) {
>+		struct kmonitor_res *r = to_kmonitor_res(tmp);
>+		if (r->target == current->pid && type & r->event_mask) {
>+			info.si_signo = r->signal;
>+			info.si_code = SI_QUEUE;
>+			info.si_int = type;
>+			info.si_pid = tsk->pid;
>+			info.si_uid = tsk->uid;
>+			kill_proc_info(r->signal, &info, r->monitor);
>+		}
>+	}
>+	read_unlock(&kmonitor_resources[bucket].lock);
>+}
>+
>+static int kmonitor_open(struct inode *inode, struct file *file)
>+{
>+	atomic_inc(&kmonitor_active);
>+	return 0;
>+}
>+
>+static int kmonitor_release(struct inode *inode, struct file *file)
>+{
>+	struct list_head *tmp, *next;
>+	int i;
>+
>+	TRACE("%p, %p", inode, file);
>+	atomic_dec(&kmonitor_active);
>+
>+	/*
>+	 * Remove any resources associated with this monitor
>+	 */
>+	for (i=0; i<(1<<KMONITOR_BITS); i++) {
>+		write_lock(&kmonitor_resources[i].lock);
>+		list_for_each_safe(tmp, next, &kmonitor_resources[i].list) {
>+			struct kmonitor_res *r = to_kmonitor_res(tmp);
>+			if (r->monitor == current->pid) {
>+				list_del(tmp);
>+				kmem_cache_free(kmonitor_cache, r);
>+			} 
>+		}
>+		write_unlock(&kmonitor_resources[i].lock);
>+	}
>+
>+	return 0;
>+}
>+
>+static int kmonitor_ioctl(struct inode *inode, struct file *file,
>+			  unsigned int cmd, unsigned long arg)
>+{
>+	struct kmonitor_cmd hdr;
>+
>+	TRACE("%p, %p, %i, %i", inode, file, (int)cmd, (int)arg);
>+	if (copy_from_user((struct kmonitor_cmd *)&hdr, 
>+			   (struct kmonitor_cmd *)arg, 
>+			   sizeof(struct kmonitor_cmd)))
>+		return -EFAULT;
>+
>+	switch (cmd) {
>+	case KMONITOR_IOW_REGISTER:
>+		return kmonitor_add(hdr.pid, hdr.type, hdr.signal);
>+	case KMONITOR_IOW_DEREGISTER:
>+		return kmonitor_remove(hdr.pid, hdr.type);		
>+	}
>+
>+	DBG("Unexpected ioctl, %i", cmd);
>+	return -EINVAL;
>+}
>+
>+static struct file_operations kmonitor_fops = {
>+	.owner		= THIS_MODULE,
>+	.llseek		= no_llseek,
>+	.open           = kmonitor_open,
>+	.release	= kmonitor_release,
>+	.ioctl          = kmonitor_ioctl,
>+};
>+
>+static struct miscdevice kmonitor_miscdev = {
>+	.minor		= KMONITOR_MINOR,
>+	.name		= "kmonitor",
>+	.fops		= &kmonitor_fops,
>+};
>+
>+static int __init kmonitor_init(void)
>+{
>+	int ret, i;
>+
>+	TRACE("void");
>+
>+	for (i=0; i<(1<<KMONITOR_BITS); i++) {
>+		INIT_LIST_HEAD(&kmonitor_resources[i].list);
>+		kmonitor_resources[i].lock = RW_LOCK_UNLOCKED;
>+	}
>+
>+	ret = misc_register(&kmonitor_miscdev);
>+	if (ret) {
>+		printk(KERN_ERR "unable to register kmonitor misc device\n");
>+		goto error_misc_drvr_register;
>+	}
>+
>+	kmonitor_cache = kmem_cache_create("kmonitor_res", 
>+					   sizeof(struct kmonitor_res), 0, 
>+					   SLAB_HWCACHE_ALIGN,
>+					   NULL, NULL);
>+	if (!kmonitor_cache) {
>+		printk(KERN_ERR "unable to allocate kmonitor_cache\n");
>+		ret = -EINVAL;
>+		goto error_in_kmonitor_cache;
>+	}
>+
>+	return 0;
>+
>+ error_in_kmonitor_cache:
>+	misc_deregister(&kmonitor_miscdev);
>+ error_misc_drvr_register:
>+	return ret;
>+}
>+
>+static void __exit kmonitor_exit(void)
>+{
>+	struct list_head *tmp, *next;
>+	int i;
>+
>+	TRACE("void");
>+	misc_deregister(&kmonitor_miscdev);
>+	for (i=0; i<(1<<KMONITOR_BITS); i++) {
>+		write_lock(&kmonitor_resources[i].lock);
>+		list_for_each_safe(tmp, next, &kmonitor_resources[i].list) {
>+			struct kmonitor_res *r = to_kmonitor_res(tmp);
>+			list_del(tmp);
>+			kmem_cache_free(kmonitor_cache, r);
>+		}
>+		write_unlock(&kmonitor_resources[i].lock);
>+	}
>+	kmem_cache_destroy(kmonitor_cache);
>+}
>+
>+module_init(kmonitor_init);
>+module_exit(kmonitor_exit);
>+
>+MODULE_AUTHOR("Atul Sabharwal");
>+MODULE_DESCRIPTION("Kmonitor Char Driver");
>+MODULE_LICENSE("GPL");
>+MODULE_ALIAS_MISCDEV(KMONITOR_MINOR);
>diff -Nru a/fs/exec.c b/fs/exec.c
>--- a/fs/exec.c	2004-06-14 11:24:08 -07:00
>+++ b/fs/exec.c	2004-06-14 11:24:08 -07:00
>@@ -46,6 +46,7 @@
> #include <linux/security.h>
> #include <linux/syscalls.h>
> #include <linux/rmap.h>
>+#include <linux/kmonitor.h>
> 
> #include <asm/uaccess.h>
> #include <asm/pgalloc.h>
>@@ -1144,6 +1145,7 @@
> 		free_arg_pages(&bprm);
> 
> 		/* execve success */
>+		kmonitor_notify_event(current, KMONITOR_PROCESS_EXEC);
> 		security_bprm_free(&bprm);
> 		return retval;
> 	}
>diff -Nru a/include/linux/kmonitor.h b/include/linux/kmonitor.h
>--- /dev/null	Wed Dec 31 16:00:00 196900
>+++ b/include/linux/kmonitor.h	2004-06-14 11:24:08 -07:00
>@@ -0,0 +1,62 @@
>+/* 
>+ *
>+ * linux/kmonitor.h
>+ *
>+ * Copyright (C) 2004 Intel Corporation.  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 v2.0 as published by the Free Software Foundation; 
>+ *
>+ * 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 021110-1307, USA.
>+ *
>+ * Authors: Atul Sabharwal <atul.sabharwal@intel.com>
>+ *               
>+ */
>+#ifndef _LINUX_KMONITOR_H_
>+#define _LINUX_KMONITOR_H_
>+
>+#include <asm/atomic.h>
>+
>+#define KMONITOR_THREAD_CREATE 0x01 
>+#define KMONITOR_THREAD_ABORT  0x02           
>+#define KMONITOR_THREAD_EXIT   0x04
>+#define KMONITOR_PROCESS_FORK  0x08
>+#define KMONITOR_PROCESS_ABORT 0x10 
>+#define KMONITOR_PROCESS_EXEC  0x20 
>+#define KMONITOR_PROCESS_EXIT  0x40
>+
>+struct kmonitor_cmd 
>+{
>+	pid_t pid;
>+	int type;
>+	int signal;
>+};
>+
>+#define KMONITOR_IOW_REGISTER   _IOW(0xDE, 1, struct kmonitor_cmd)
>+#define KMONITOR_IOW_DEREGISTER _IOW(0xDE, 2, struct kmonitor_cmd)
>+
>+#ifdef __KERNEL__
>+#include <linux/sysctl.h>
>+
>+extern  atomic_t  kmonitor_active;
>+extern void __kmonitor_notify_event(struct task_struct *tsk, int type);
>+
>+static inline void kmonitor_notify_event( struct task_struct *tsk, int type)
>+{
>+#ifdef CONFIG_KMONITOR	
>+	if (atomic_read(&kmonitor_active))
>+		__kmonitor_notify_event(tsk, type);
>+#endif /* CONFIG_KMONITOR */
>+}
>+#endif /* __KERNEL__ */
>+#endif /* _LINUX_KMONITOR_H_ */
>+
>diff -Nru a/include/linux/miscdevice.h b/include/linux/miscdevice.h
>--- a/include/linux/miscdevice.h	2004-06-14 11:24:08 -07:00
>+++ b/include/linux/miscdevice.h	2004-06-14 11:24:08 -07:00
>@@ -35,6 +35,7 @@
> #define SGI_USEMACLONE	     151
> 
> #define TUN_MINOR	     200
>+#define KMONITOR_MINOR	     221
> 
> struct device;
> 
>diff -Nru a/kernel/exit.c b/kernel/exit.c
>--- a/kernel/exit.c	2004-06-14 11:24:08 -07:00
>+++ b/kernel/exit.c	2004-06-14 11:24:08 -07:00
>@@ -22,6 +22,7 @@
> #include <linux/profile.h>
> #include <linux/mount.h>
> #include <linux/proc_fs.h>
>+#include <linux/kmonitor.h>
> 
> #include <asm/uaccess.h>
> #include <asm/pgtable.h>
>@@ -748,6 +749,11 @@
> 	 */
> 	_raw_write_unlock(&tasklist_lock);
> 	local_irq_enable();
>+
>+	if (tsk->pid == tsk->tgid)
>+		kmonitor_notify_event(tsk, KMONITOR_PROCESS_EXIT);
>+	else
>+		kmonitor_notify_event(tsk, KMONITOR_THREAD_EXIT);
> 
> 	/* If the process is dead, release it - nobody will wait for it */
> 	if (state == TASK_DEAD)
>diff -Nru a/kernel/fork.c b/kernel/fork.c
>--- a/kernel/fork.c	2004-06-14 11:24:08 -07:00
>+++ b/kernel/fork.c	2004-06-14 11:24:08 -07:00
>@@ -41,6 +41,7 @@
> #include <asm/mmu_context.h>
> #include <asm/cacheflush.h>
> #include <asm/tlbflush.h>
>+#include <linux/kmonitor.h>
> 
> /* The idle threads do not count..
>  * Protected by write_lock_irq(&tasklist_lock)
>@@ -1167,6 +1168,11 @@
> 
> 	if (!IS_ERR(p)) {
> 		struct completion vfork;
>+
>+                if (p->pid == p->tgid)
>+                        kmonitor_notify_event(p, KMONITOR_PROCESS_FORK);
>+                else
>+                        kmonitor_notify_event(p, KMONITOR_THREAD_CREATE);
> 
> 		if (clone_flags & CLONE_VFORK) {
> 			p->vfork_done = &vfork;
>  
>


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