1 files changed, 32 insertions, 8 deletions

diff --git a/sys/dev/filemon/filemon.c b/sys/dev/filemon/filemon.c
index b302de9..352f682 100644
--- a/sys/dev/filemon/filemon.c
+++ b/sys/dev/filemon/filemon.c
@@ -89,7 +89,7 @@ struct filemon {
 	TAILQ_ENTRY(filemon) link;	/* Link into the in-use list. */
 	struct sx	lock;		/* Lock mutex for this filemon. */
 	struct file	*fp;		/* Output file pointer. */
-	pid_t		pid;		/* The process ID being monitored. */
+	struct proc     *p;		/* The process being monitored. */
 	char		fname1[MAXPATHLEN]; /* Temporary filename buffer. */
 	char		fname2[MAXPATHLEN]; /* Temporary filename buffer. */
 	char		msgbufr[1024];	/* Output message buffer. */
@@ -105,26 +105,45 @@ static struct cdev *filemon_dev;
 #include "filemon_wrapper.c"
 
 static void
+filemon_comment(struct filemon *filemon)
+{
+	int len;
+	struct timeval now;
+
+	getmicrotime(&now);
+
+	len = snprintf(filemon->msgbufr, sizeof(filemon->msgbufr),
+	    "# filemon version %d\n# Target pid %d\n# Start %ju.%06ju\nV %d\n",
+	    FILEMON_VERSION, curproc->p_pid, (uintmax_t)now.tv_sec,
+	    (uintmax_t)now.tv_usec, FILEMON_VERSION);
+
+	filemon_output(filemon, filemon->msgbufr, len);
+}
+
+static void
 filemon_dtr(void *data)
 {
 	struct filemon *filemon = data;
 
 	if (filemon != NULL) {
-		struct file *fp = filemon->fp;
+		struct file *fp;
 
-		/* Get exclusive write access. */
+		/* Follow same locking order as filemon_pid_check. */
 		filemon_lock_write();
+		filemon_filemon_lock(filemon);
 
 		/* Remove from the in-use list. */
 		TAILQ_REMOVE(&filemons_inuse, filemon, link);
 
+		fp = filemon->fp;
 		filemon->fp = NULL;
-		filemon->pid = -1;
+		filemon->p = NULL;
 
 		/* Add to the free list. */
 		TAILQ_INSERT_TAIL(&filemons_free, filemon, link);
 
 		/* Give up write access. */
+		filemon_filemon_unlock(filemon);
 		filemon_unlock_write();
 
 		if (fp != NULL)
@@ -143,11 +162,17 @@ filemon_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int flag __unused,
 	cap_rights_t rights;
 #endif
 
-	devfs_get_cdevpriv((void **) &filemon);
+	if ((error = devfs_get_cdevpriv((void **) &filemon)) != 0)
+		return (error);
+
+	filemon_filemon_lock(filemon);
 
 	switch (cmd) {
 	/* Set the output file descriptor. */
 	case FILEMON_SET_FD:
+		if (filemon->fp != NULL)
+			fdrop(filemon->fp, td);
+
 		error = fget_write(td, *(int *)data,
 #if __FreeBSD_version >= 900041
 		    cap_rights_init(&rights, CAP_PWRITE),
@@ -163,7 +188,7 @@ filemon_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int flag __unused,
 		error = pget(*((pid_t *)data), PGET_CANDEBUG | PGET_NOTWEXIT,
 		    &p);
 		if (error == 0) {
-			filemon->pid = p->p_pid;
+			filemon->p = p;
 			PROC_UNLOCK(p);
 		}
 		break;
@@ -173,6 +198,7 @@ filemon_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int flag __unused,
 		break;
 	}
 
+	filemon_filemon_unlock(filemon);
 	return (error);
 }
 
@@ -197,8 +223,6 @@ filemon_open(struct cdev *dev, int oflags __unused, int devtype __unused,
 		sx_init(&filemon->lock, "filemon");
 	}
 
-	filemon->pid = curproc->p_pid;
-
 	devfs_set_cdevpriv(filemon, filemon_dtr);
 
 	/* Get exclusive write access. */