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, Version 1.0 only 6 * (the "License"). You may not use this file except in compliance 7 * with the License. 8 * 9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 10 * or http://www.opensolaris.org/os/licensing. 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 2005 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 * 26 * This D script is used as an example in the Solaris Dynamic Tracing Guide 27 * wiki in the "Speculative Tracing" Chapter. 28 * 29 * The full text of the this chapter may be found here: 30 * 31 * http://wikis.sun.com/display/DTrace/Speculative+Tracing 32 * 33 * On machines that have DTrace installed, this script is available as 34 * specopen.d in /usr/demo/dtrace, a directory that contains all D scripts 35 * used in the Solaris Dynamic Tracing Guide. A table of the scripts and their 36 * corresponding chapters may be found here: 37 * 38 * file:///usr/demo/dtrace/index.html 39 */ 40 41 #!/usr/sbin/dtrace -Fs 42 43 syscall::open:entry, 44 syscall::open64:entry 45 { 46 /* 47 * The call to speculation() creates a new speculation. If this fails, 48 * dtrace(1M) will generate an error message indicating the reason for 49 * the failed speculation(), but subsequent speculative tracing will be 50 * silently discarded. 51 */ 52 self->spec = speculation(); 53 speculate(self->spec); 54 55 /* 56 * Because this printf() follows the speculate(), it is being 57 * speculatively traced; it will only appear in the data buffer if the 58 * speculation is subsequently commited. 59 */ 60 printf("%s", stringof(copyinstr(arg0))); 61 } 62 63 fbt::: 64 /self->spec/ 65 { 66 /* 67 * A speculate() with no other actions speculates the default action: 68 * tracing the EPID. 69 */ 70 speculate(self->spec); 71 } 72 73 syscall::open:return, 74 syscall::open64:return 75 /self->spec/ 76 { 77 /* 78 * To balance the output with the -F option, we want to be sure that 79 * every entry has a matching return. Because we speculated the 80 * open entry above, we want to also speculate the open return. 81 * This is also a convenient time to trace the errno value. 82 */ 83 speculate(self->spec); 84 trace(errno); 85 } 86 87 syscall::open:return, 88 syscall::open64:return 89 /self->spec && errno != 0/ 90 { 91 /* 92 * If errno is non-zero, we want to commit the speculation. 93 */ 94 commit(self->spec); 95 self->spec = 0; 96 } 97 98 syscall::open:return, 99 syscall::open64:return 100 /self->spec && errno == 0/ 101 { 102 /* 103 * If errno is not set, we discard the speculation. 104 */ 105 discard(self->spec); 106 self->spec = 0; 107 } 108