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 /*
22 * Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
23 * Copyright (c) 2012, 2014 by Delphix. All rights reserved.
24 */
25
26 #include <sys/zfs_context.h>
27
28 list_t zfs_dbgmsgs;
29 int zfs_dbgmsg_size;
30 kmutex_t zfs_dbgmsgs_lock;
31 int zfs_dbgmsg_maxsize = 4<<20; /* 4MB */
32
33 void
zfs_dbgmsg_init(void)34 zfs_dbgmsg_init(void)
35 {
36 list_create(&zfs_dbgmsgs, sizeof (zfs_dbgmsg_t),
37 offsetof(zfs_dbgmsg_t, zdm_node));
38 mutex_init(&zfs_dbgmsgs_lock, NULL, MUTEX_DEFAULT, NULL);
39 }
40
41 void
zfs_dbgmsg_fini(void)42 zfs_dbgmsg_fini(void)
43 {
44 zfs_dbgmsg_t *zdm;
45
46 while ((zdm = list_remove_head(&zfs_dbgmsgs)) != NULL) {
47 int size = sizeof (zfs_dbgmsg_t) + strlen(zdm->zdm_msg);
48 kmem_free(zdm, size);
49 zfs_dbgmsg_size -= size;
50 }
51 mutex_destroy(&zfs_dbgmsgs_lock);
52 ASSERT0(zfs_dbgmsg_size);
53 }
54
55 /*
56 * Print these messages by running:
57 * echo ::zfs_dbgmsg | mdb -k
58 *
59 * Monitor these messages by running:
60 * dtrace -qn 'zfs-dbgmsg{printf("%s\n", stringof(arg0))}'
61 *
62 * When used with libzpool, monitor with:
63 * dtrace -qn 'zfs$pid::zfs_dbgmsg:probe1{printf("%s\n", copyinstr(arg1))}'
64 */
65 void
zfs_dbgmsg(const char * fmt,...)66 zfs_dbgmsg(const char *fmt, ...)
67 {
68 int size;
69 va_list adx;
70 zfs_dbgmsg_t *zdm;
71
72 va_start(adx, fmt);
73 size = vsnprintf(NULL, 0, fmt, adx);
74 va_end(adx);
75
76 /*
77 * There is one byte of string in sizeof (zfs_dbgmsg_t), used
78 * for the terminating null.
79 */
80 zdm = kmem_alloc(sizeof (zfs_dbgmsg_t) + size, KM_SLEEP);
81 zdm->zdm_timestamp = gethrestime_sec();
82 zdm->zdm_hrtime = gethrtime();
83
84 va_start(adx, fmt);
85 (void) vsnprintf(zdm->zdm_msg, size + 1, fmt, adx);
86 va_end(adx);
87
88 DTRACE_PROBE1(zfs__dbgmsg, char *, zdm->zdm_msg);
89
90 mutex_enter(&zfs_dbgmsgs_lock);
91 list_insert_tail(&zfs_dbgmsgs, zdm);
92 zfs_dbgmsg_size += sizeof (zfs_dbgmsg_t) + size;
93 while (zfs_dbgmsg_size > zfs_dbgmsg_maxsize) {
94 zdm = list_remove_head(&zfs_dbgmsgs);
95 size = sizeof (zfs_dbgmsg_t) + strlen(zdm->zdm_msg);
96 kmem_free(zdm, size);
97 zfs_dbgmsg_size -= size;
98 }
99 mutex_exit(&zfs_dbgmsgs_lock);
100 }
101
102 void
zfs_dbgmsg_print(const char * tag)103 zfs_dbgmsg_print(const char *tag)
104 {
105 zfs_dbgmsg_t *zdm;
106
107 (void) printf("ZFS_DBGMSG(%s):\n", tag);
108 mutex_enter(&zfs_dbgmsgs_lock);
109 for (zdm = list_head(&zfs_dbgmsgs); zdm;
110 zdm = list_next(&zfs_dbgmsgs, zdm))
111 (void) printf("%s\n", zdm->zdm_msg);
112 mutex_exit(&zfs_dbgmsgs_lock);
113 }
114