PERFORCE change 95902 for review

[John Birrell]

http://perforce.freebsd.org/chv.cgi?CH=95902

Change 95902 by jb at jb_freebsd2 on 2006/04/22 23:29:54

	Create/destroy the dtrace state when opening/closing the cloned
	device.

Affected files ...

.. //depot/projects/dtrace/src/sys/cddl/dev/dtrace/dtrace_close.c#3 edit
.. //depot/projects/dtrace/src/sys/cddl/dev/dtrace/dtrace_open.c#3 edit

Differences ...

==== //depot/projects/dtrace/src/sys/cddl/dev/dtrace/dtrace_close.c#3 (text+ko) ====

@@ -27,13 +27,40 @@
 dtrace_close(struct cdev *dev __unused, int flags, int fmt __unused,
     struct thread *td)
 {
-	/* Check if this is a cloned device. */
-	if (minor(dev) > 0) {
-		/* XXX Do the state destruction cleanup here. */
+	dtrace_state_t *state = dev->si_drv1;
+
+	/* Check if this is not a cloned device. */
+	if (minor(dev) == 0)
+		return (0);
+printf("%s: struct cdev %p curthread %p si_drv0 %u\n",__FUNCTION__,dev,curthread,dev->si_drv0);
+
+	mutex_enter(&cpu_lock);
+	mutex_enter(&dtrace_lock);
+
+	if (state != NULL) {
+		if (state->dts_anon) {
+			/*
+			 * There is anonymous state.
+			 * Destroy that first.
+			 */
+			ASSERT(dtrace_anon.dta_state == NULL);
+			dtrace_state_destroy(state->dts_anon);
+		}
+
+		dtrace_state_destroy(state);
 
-		/* Destroy the cloned device. */
-		destroy_dev(dev);
+		free(state, M_DTRACE);
+		dev->si_drv1 = NULL;
 	}
 
+	mutex_exit(&dtrace_lock);
+	mutex_exit(&cpu_lock);
+	ASSERT(dtrace_opens > 0);
+	if (--dtrace_opens == 0)
+		(void) kdi_dtrace_set(KDI_DTSET_DTRACE_DEACTIVATE);
+
+	/* Destroy the cloned device. */
+	destroy_dev(dev);
+
 	return (0);
 }

==== //depot/projects/dtrace/src/sys/cddl/dev/dtrace/dtrace_open.c#3 (text+ko) ====

@@ -26,7 +26,11 @@
 static int
 dtrace_open(struct cdev *dev, int oflags, int devtype, struct thread *td)
 {
+	dtrace_state_t *state = NULL;
 	int error = 0;
+	uint32_t priv;
+	uid_t uid;
+	zoneid_t zoneid;
 
 	/*
 	 * The first minor device is the one that is cloned so there is
@@ -34,7 +38,58 @@
 	 */
 	if (minor(dev) == 0)
 		return 0;
+printf("%s: struct cdev %p curthread %p si_drv0 %u si_cred %p\n",__FUNCTION__,dev,curthread,dev->si_drv0,dev->si_cred);
 
-printf("%s: struct cdev %p curthread %p si_drv0 %u\n",__FUNCTION__,dev,curthread,dev->si_drv0);
+	/*
+	 * If no DTRACE_PRIV_* bits are set in the credential, then the
+	 * caller lacks sufficient permission to do anything with DTrace.
+	 */
+	dtrace_cred2priv(dev->si_cred, &priv, &uid, &zoneid);
+	if (priv == DTRACE_PRIV_NONE) {
+		/* Destroy the cloned device. */
+		destroy_dev(dev);
+		return (EACCES);
+	}
+
+	/*
+	 * Ask all providers to provide all their probes.
+	 */
+	mutex_enter(&dtrace_provider_lock);
+	dtrace_probe_provide(NULL, NULL);
+	mutex_exit(&dtrace_provider_lock);
+
+	mutex_enter(&cpu_lock);
+	mutex_enter(&dtrace_lock);
+	dtrace_opens++;
+	dtrace_membar_producer();
+
+	/*
+	 * If the kernel debugger is active (that is, if the kernel debugger
+	 * modified text in some way), we won't allow the open.
+	 */
+	if (kdi_dtrace_set(KDI_DTSET_DTRACE_ACTIVATE) != 0) {
+		dtrace_opens--;
+		mutex_exit(&cpu_lock);
+		mutex_exit(&dtrace_lock);
+
+		/* Destroy the cloned device. */
+		destroy_dev(dev);
+		return (EBUSY);
+	}
+
+	state = dtrace_state_create(dev);
+	mutex_exit(&cpu_lock);
+
+	if (state == NULL) {
+		if (--dtrace_opens == 0)
+			(void) kdi_dtrace_set(KDI_DTSET_DTRACE_DEACTIVATE);
+		mutex_exit(&dtrace_lock);
+
+		/* Destroy the cloned device. */
+		destroy_dev(dev);
+		return (EAGAIN);
+	}
+
+	mutex_exit(&dtrace_lock);
 	return (error);
 }