xref: /onnv-gate/usr/src/cmd/dtrace/demo/spec/specopen.d (revision 0:68f95e015346)
1*0Sstevel@tonic-gate /*
2*0Sstevel@tonic-gate  * CDDL HEADER START
3*0Sstevel@tonic-gate  *
4*0Sstevel@tonic-gate  * The contents of this file are subject to the terms of the
5*0Sstevel@tonic-gate  * Common Development and Distribution License, Version 1.0 only
6*0Sstevel@tonic-gate  * (the "License").  You may not use this file except in compliance
7*0Sstevel@tonic-gate  * with the License.
8*0Sstevel@tonic-gate  *
9*0Sstevel@tonic-gate  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10*0Sstevel@tonic-gate  * or http://www.opensolaris.org/os/licensing.
11*0Sstevel@tonic-gate  * See the License for the specific language governing permissions
12*0Sstevel@tonic-gate  * and limitations under the License.
13*0Sstevel@tonic-gate  *
14*0Sstevel@tonic-gate  * When distributing Covered Code, include this CDDL HEADER in each
15*0Sstevel@tonic-gate  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16*0Sstevel@tonic-gate  * If applicable, add the following below this CDDL HEADER, with the
17*0Sstevel@tonic-gate  * fields enclosed by brackets "[]" replaced with your own identifying
18*0Sstevel@tonic-gate  * information: Portions Copyright [yyyy] [name of copyright owner]
19*0Sstevel@tonic-gate  *
20*0Sstevel@tonic-gate  * CDDL HEADER END
21*0Sstevel@tonic-gate  */
22*0Sstevel@tonic-gate /*
23*0Sstevel@tonic-gate  * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
24*0Sstevel@tonic-gate  * Use is subject to license terms.
25*0Sstevel@tonic-gate  */
26*0Sstevel@tonic-gate 
27*0Sstevel@tonic-gate #!/usr/sbin/dtrace -Fs
28*0Sstevel@tonic-gate 
29*0Sstevel@tonic-gate syscall::open:entry,
30*0Sstevel@tonic-gate syscall::open64:entry
31*0Sstevel@tonic-gate {
32*0Sstevel@tonic-gate 	/*
33*0Sstevel@tonic-gate 	 * The call to speculation() creates a new speculation.  If this fails,
34*0Sstevel@tonic-gate 	 * dtrace(1M) will generate an error message indicating the reason for
35*0Sstevel@tonic-gate 	 * the failed speculation(), but subsequent speculative tracing will be
36*0Sstevel@tonic-gate 	 * silently discarded.
37*0Sstevel@tonic-gate 	 */
38*0Sstevel@tonic-gate 	self->spec = speculation();
39*0Sstevel@tonic-gate 	speculate(self->spec);
40*0Sstevel@tonic-gate 
41*0Sstevel@tonic-gate 	/*
42*0Sstevel@tonic-gate 	 * Because this printf() follows the speculate(), it is being
43*0Sstevel@tonic-gate 	 * speculatively traced; it will only appear in the data buffer if the
44*0Sstevel@tonic-gate 	 * speculation is subsequently commited.
45*0Sstevel@tonic-gate 	 */
46*0Sstevel@tonic-gate 	printf("%s", stringof(copyinstr(arg0)));
47*0Sstevel@tonic-gate }
48*0Sstevel@tonic-gate 
49*0Sstevel@tonic-gate fbt:::
50*0Sstevel@tonic-gate /self->spec/
51*0Sstevel@tonic-gate {
52*0Sstevel@tonic-gate 	/*
53*0Sstevel@tonic-gate 	 * A speculate() with no other actions speculates the default action:
54*0Sstevel@tonic-gate 	 * tracing the EPID.
55*0Sstevel@tonic-gate 	 */
56*0Sstevel@tonic-gate 	speculate(self->spec);
57*0Sstevel@tonic-gate }
58*0Sstevel@tonic-gate 
59*0Sstevel@tonic-gate syscall::open:return,
60*0Sstevel@tonic-gate syscall::open64:return
61*0Sstevel@tonic-gate /self->spec/
62*0Sstevel@tonic-gate {
63*0Sstevel@tonic-gate 	/*
64*0Sstevel@tonic-gate 	 * To balance the output with the -F option, we want to be sure that
65*0Sstevel@tonic-gate 	 * every entry has a matching return.  Because we speculated the
66*0Sstevel@tonic-gate 	 * open entry above, we want to also speculate the open return.
67*0Sstevel@tonic-gate 	 * This is also a convenient time to trace the errno value.
68*0Sstevel@tonic-gate 	 */
69*0Sstevel@tonic-gate 	speculate(self->spec);
70*0Sstevel@tonic-gate 	trace(errno);
71*0Sstevel@tonic-gate }
72*0Sstevel@tonic-gate 
73*0Sstevel@tonic-gate syscall::open:return,
74*0Sstevel@tonic-gate syscall::open64:return
75*0Sstevel@tonic-gate /self->spec && errno != 0/
76*0Sstevel@tonic-gate {
77*0Sstevel@tonic-gate 	/*
78*0Sstevel@tonic-gate 	 * If errno is non-zero, we want to commit the speculation.
79*0Sstevel@tonic-gate 	 */
80*0Sstevel@tonic-gate 	commit(self->spec);
81*0Sstevel@tonic-gate 	self->spec = 0;
82*0Sstevel@tonic-gate }
83*0Sstevel@tonic-gate 
84*0Sstevel@tonic-gate syscall::open:return,
85*0Sstevel@tonic-gate syscall::open64:return
86*0Sstevel@tonic-gate /self->spec && errno == 0/
87*0Sstevel@tonic-gate {
88*0Sstevel@tonic-gate 	/*
89*0Sstevel@tonic-gate 	 * If errno is not set, we discard the speculation.
90*0Sstevel@tonic-gate 	 */
91*0Sstevel@tonic-gate 	discard(self->spec);
92*0Sstevel@tonic-gate 	self->spec = 0;
93*0Sstevel@tonic-gate }
94