xref: /freebsd/sys/cddl/dev/dtrace/dtrace_unload.c (revision f8ea072a542112d5e0e74a2d6ecf75d967c3054c)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  *
21  * $FreeBSD$
22  *
23  */
24 
25 static int
26 dtrace_unload()
27 {
28 	dtrace_state_t *state;
29 	int error = 0;
30 
31 #if __FreeBSD_version < 800039
32 	/*
33 	 * Check if there is still an event handler callback
34 	 * registered.
35 	 */
36 	if (eh_tag != 0) {
37 		/* De-register the device cloning event handler. */
38 		EVENTHANDLER_DEREGISTER(dev_clone, eh_tag);
39 		eh_tag = 0;
40 
41 		/* Stop device cloning. */
42 		clone_cleanup(&dtrace_clones);
43 	}
44 #else
45 	destroy_dev(dtrace_dev);
46 	destroy_dev(helper_dev);
47 #endif
48 
49 	mutex_enter(&dtrace_provider_lock);
50 	mutex_enter(&dtrace_lock);
51 	mutex_enter(&cpu_lock);
52 
53 	ASSERT(dtrace_opens == 0);
54 
55 	if (dtrace_helpers > 0) {
56 		mutex_exit(&cpu_lock);
57 		mutex_exit(&dtrace_lock);
58 		mutex_exit(&dtrace_provider_lock);
59 		return (EBUSY);
60 	}
61 
62 	if (dtrace_unregister((dtrace_provider_id_t)dtrace_provider) != 0) {
63 		mutex_exit(&cpu_lock);
64 		mutex_exit(&dtrace_lock);
65 		mutex_exit(&dtrace_provider_lock);
66 		return (EBUSY);
67 	}
68 
69 	dtrace_provider = NULL;
70 
71 	if ((state = dtrace_anon_grab()) != NULL) {
72 		/*
73 		 * If there were ECBs on this state, the provider should
74 		 * have not been allowed to detach; assert that there is
75 		 * none.
76 		 */
77 		ASSERT(state->dts_necbs == 0);
78 		dtrace_state_destroy(state);
79 	}
80 
81 	bzero(&dtrace_anon, sizeof (dtrace_anon_t));
82 
83 	mutex_exit(&cpu_lock);
84 
85 	if (dtrace_helptrace_enabled) {
86 		kmem_free(dtrace_helptrace_buffer, 0);
87 		dtrace_helptrace_buffer = NULL;
88 	}
89 
90 	if (dtrace_probes != NULL) {
91 		kmem_free(dtrace_probes, 0);
92 		dtrace_probes = NULL;
93 		dtrace_nprobes = 0;
94 	}
95 
96 	dtrace_hash_destroy(dtrace_bymod);
97 	dtrace_hash_destroy(dtrace_byfunc);
98 	dtrace_hash_destroy(dtrace_byname);
99 	dtrace_bymod = NULL;
100 	dtrace_byfunc = NULL;
101 	dtrace_byname = NULL;
102 
103 	kmem_cache_destroy(dtrace_state_cache);
104 
105 	delete_unrhdr(dtrace_arena);
106 
107 	if (dtrace_toxrange != NULL) {
108 		kmem_free(dtrace_toxrange, 0);
109 		dtrace_toxrange = NULL;
110 		dtrace_toxranges = 0;
111 		dtrace_toxranges_max = 0;
112 	}
113 
114 	ASSERT(dtrace_vtime_references == 0);
115 	ASSERT(dtrace_opens == 0);
116 	ASSERT(dtrace_retained == NULL);
117 
118 	mutex_exit(&dtrace_lock);
119 	mutex_exit(&dtrace_provider_lock);
120 
121 	mutex_destroy(&dtrace_meta_lock);
122 	mutex_destroy(&dtrace_provider_lock);
123 	mutex_destroy(&dtrace_lock);
124 	mutex_destroy(&dtrace_errlock);
125 
126 	/* Reset our hook for exceptions. */
127 	dtrace_invop_uninit();
128 
129 	/*
130 	 * Reset our hook for thread switches, but ensure that vtime isn't
131 	 * active first.
132 	 */
133 	dtrace_vtime_active = 0;
134 	dtrace_vtime_switch_func = NULL;
135 
136 	/* Unhook from the trap handler. */
137 	dtrace_trap_func = NULL;
138 
139 	return (error);
140 }
141