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 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 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 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 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 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 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