1 // SPDX-License-Identifier: CDDL-1.0
2 /*
3 * CDDL HEADER START
4 *
5 * The contents of this file are subject to the terms of the
6 * Common Development and Distribution License (the "License").
7 * You may not use this file except in compliance with the License.
8 *
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or https://opensource.org/licenses/CDDL-1.0.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
13 *
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 *
20 * CDDL HEADER END
21 */
22 /*
23 * Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
24 * Copyright (c) 2012, 2014 by Delphix. All rights reserved.
25 * Copyright (c) 2024, Rob Norris <robn@despairlabs.com>
26 */
27
28 #include <sys/zfs_context.h>
29
30 typedef struct zfs_dbgmsg {
31 list_node_t zdm_node;
32 uint64_t zdm_timestamp;
33 uint_t zdm_size;
34 char zdm_msg[]; /* variable length allocation */
35 } zfs_dbgmsg_t;
36
37 static list_t zfs_dbgmsgs;
38 static kmutex_t zfs_dbgmsgs_lock;
39 static uint_t zfs_dbgmsg_size = 0;
40 static uint_t zfs_dbgmsg_maxsize = 4<<20; /* 4MB */
41
42 int zfs_dbgmsg_enable = B_TRUE;
43
44 static void
zfs_dbgmsg_purge(uint_t max_size)45 zfs_dbgmsg_purge(uint_t max_size)
46 {
47 while (zfs_dbgmsg_size > max_size) {
48 zfs_dbgmsg_t *zdm = list_remove_head(&zfs_dbgmsgs);
49 if (zdm == NULL)
50 return;
51
52 uint_t size = zdm->zdm_size;
53 kmem_free(zdm, size);
54 zfs_dbgmsg_size -= size;
55 }
56 }
57
58 void
zfs_dbgmsg_init(void)59 zfs_dbgmsg_init(void)
60 {
61 list_create(&zfs_dbgmsgs, sizeof (zfs_dbgmsg_t),
62 offsetof(zfs_dbgmsg_t, zdm_node));
63 mutex_init(&zfs_dbgmsgs_lock, NULL, MUTEX_DEFAULT, NULL);
64 }
65
66 void
zfs_dbgmsg_fini(void)67 zfs_dbgmsg_fini(void)
68 {
69 zfs_dbgmsg_t *zdm;
70 while ((zdm = list_remove_head(&zfs_dbgmsgs)))
71 umem_free(zdm, zdm->zdm_size);
72 mutex_destroy(&zfs_dbgmsgs_lock);
73 }
74
75 void
__set_error(const char * file,const char * func,int line,int err)76 __set_error(const char *file, const char *func, int line, int err)
77 {
78 if (zfs_flags & ZFS_DEBUG_SET_ERROR)
79 __dprintf(B_FALSE, file, func, line, "error %lu",
80 (ulong_t)err);
81 }
82
83 void
__zfs_dbgmsg(char * buf)84 __zfs_dbgmsg(char *buf)
85 {
86 uint_t size = sizeof (zfs_dbgmsg_t) + strlen(buf) + 1;
87 zfs_dbgmsg_t *zdm = umem_zalloc(size, KM_SLEEP);
88 zdm->zdm_size = size;
89 zdm->zdm_timestamp = gethrestime_sec();
90 strcpy(zdm->zdm_msg, buf);
91
92 mutex_enter(&zfs_dbgmsgs_lock);
93 list_insert_tail(&zfs_dbgmsgs, zdm);
94 zfs_dbgmsg_size += size;
95 zfs_dbgmsg_purge(zfs_dbgmsg_maxsize);
96 mutex_exit(&zfs_dbgmsgs_lock);
97 }
98
99 void
zfs_dbgmsg_print(int fd,const char * tag)100 zfs_dbgmsg_print(int fd, const char *tag)
101 {
102 ssize_t ret __attribute__((unused));
103
104 mutex_enter(&zfs_dbgmsgs_lock);
105
106 /*
107 * We use write() in this function instead of printf()
108 * so it is safe to call from a signal handler.
109 */
110 ret = write(fd, "ZFS_DBGMSG(", 11);
111 ret = write(fd, tag, strlen(tag));
112 ret = write(fd, ") START:\n", 9);
113
114 for (zfs_dbgmsg_t *zdm = list_head(&zfs_dbgmsgs); zdm != NULL;
115 zdm = list_next(&zfs_dbgmsgs, zdm)) {
116 ret = write(fd, zdm->zdm_msg, strlen(zdm->zdm_msg));
117 ret = write(fd, "\n", 1);
118 }
119
120 ret = write(fd, "ZFS_DBGMSG(", 11);
121 ret = write(fd, tag, strlen(tag));
122 ret = write(fd, ") END\n", 6);
123
124 mutex_exit(&zfs_dbgmsgs_lock);
125 }
126