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/*
23 * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
24 * Use is subject to license terms.
25 */
26
27#include <sys/types.h>
28#include <sys/sysmacros.h>
29
30#include <ucontext.h>
31#include <strings.h>
32#include <stdio.h>
33#include <errno.h>
34
35#include <fmd_trace.h>
36#include <fmd_alloc.h>
37#include <fmd_subr.h>
38#include <fmd_conf.h>
39#include <fmd.h>
40
41fmd_tracebuf_t *
42fmd_trace_create(void)
43{
44	fmd_tracebuf_t *tbp = fmd_zalloc(sizeof (fmd_tracebuf_t), FMD_SLEEP);
45	size_t bufsize;
46
47	(void) fmd_conf_getprop(fmd.d_conf, "trace.frames", &tbp->tb_frames);
48	(void) fmd_conf_getprop(fmd.d_conf, "trace.recs", &tbp->tb_recs);
49
50	/*
51	 * We require 8-byte alignment of fmd_tracerec_t to store hrtime_t's.
52	 * Since the trailing flexible array member is of type uintptr_t, we
53	 * may need to allocate an additional element if we are compiling
54	 * 32-bit; otherwise uintptr_t is 8 bytes so any value of tb_frames is
55	 * acceptable.
56	 *
57	 * tb_frames includes the first element, whose size is reflected in
58	 * sizeof (fmd_tracerec_t).  Therefore, if fmd_tracerec_t's size is
59	 * 0 mod 8, we must be sure the total number of frames is odd.
60	 * Otherwise, we need at least one extra frame, so the total count
61	 * must be even.  This will continue to work even if the sizes or
62	 * types of other fmd_tracerec_t members are changed.
63	 */
64#ifdef _ILP32
65	/*CONSTCOND*/
66	if (sizeof (fmd_tracerec_t) % sizeof (hrtime_t) == 0)
67		tbp->tb_frames = (tbp->tb_frames & ~1UL) + 1;
68	else
69		tbp->tb_frames = P2ROUNDUP(tbp->tb_frames, 2);
70#endif
71	tbp->tb_size = sizeof (fmd_tracerec_t) +
72	    sizeof (uintptr_t) * (MAX(tbp->tb_frames, 1) - 1);
73
74	bufsize = tbp->tb_size * tbp->tb_recs;
75
76	tbp->tb_buf = fmd_zalloc(bufsize, FMD_SLEEP);
77	tbp->tb_end = (void *)((uintptr_t)tbp->tb_buf + bufsize - tbp->tb_size);
78	tbp->tb_ptr = tbp->tb_buf;
79
80	return (tbp);
81}
82
83void
84fmd_trace_destroy(fmd_tracebuf_t *tbp)
85{
86	fmd_free(tbp->tb_buf, tbp->tb_size * tbp->tb_recs);
87	fmd_free(tbp, sizeof (fmd_tracebuf_t));
88}
89
90/*
91 * Callback for walkcontext(3C) to store the stack trace.  We use tr_tag below
92 * to store the maximum value of depth that is permitted so we can use it here.
93 */
94/*ARGSUSED*/
95static int
96fmd_trace_frame(uintptr_t pc, int sig, fmd_tracerec_t *trp)
97{
98	trp->tr_stack[trp->tr_depth++] = pc;
99	return (trp->tr_depth >= trp->tr_tag);
100}
101
102/*ARGSUSED*/
103fmd_tracerec_t *
104fmd_trace_none(fmd_tracebuf_t *tbp, uint_t tag, const char *format, va_list ap)
105{
106	return (NULL);
107}
108
109fmd_tracerec_t *
110fmd_trace_lite(fmd_tracebuf_t *tbp, uint_t tag, const char *format, va_list ap)
111{
112	hrtime_t time = gethrtime();
113	fmd_tracerec_t *trp = tbp->tb_ptr;
114	char *p;
115
116	if (tbp->tb_depth++ != 0) {
117		tbp->tb_depth--;
118		return (NULL);
119	}
120
121	trp->tr_time = time;
122	trp->tr_file = NULL;
123	trp->tr_line = 0;
124	trp->tr_errno = (tag == FMD_DBG_ERR) ? errno : 0;
125	trp->tr_tag = fmd_ntz32(tag);
126
127	(void) vsnprintf(trp->tr_msg, sizeof (trp->tr_msg), format, ap);
128	p = &trp->tr_msg[strlen(trp->tr_msg)];
129	if (p > trp->tr_msg && p[-1] == '\n')
130		p[-1] = '\0';
131
132	if (tbp->tb_ptr != tbp->tb_end)
133		tbp->tb_ptr = (void *)((uintptr_t)tbp->tb_ptr + tbp->tb_size);
134	else
135		tbp->tb_ptr = tbp->tb_buf;
136
137	tbp->tb_depth--;
138	return (trp);
139}
140
141fmd_tracerec_t *
142fmd_trace_full(fmd_tracebuf_t *tbp, uint_t tag, const char *format, va_list ap)
143{
144	hrtime_t time = gethrtime();
145	fmd_tracerec_t *trp = tbp->tb_ptr;
146	ucontext_t uc;
147	char *p;
148
149	if (tbp->tb_depth++ != 0) {
150		tbp->tb_depth--;
151		return (NULL);
152	}
153
154	(void) getcontext(&uc);
155	trp->tr_depth = 0;
156	trp->tr_tag = tbp->tb_frames; /* for use by fmd_trace_frame() */
157	(void) walkcontext(&uc, (int (*)())fmd_trace_frame, trp);
158
159	trp->tr_time = time;
160	trp->tr_file = NULL;
161	trp->tr_line = 0;
162	trp->tr_errno = (tag == FMD_DBG_ERR) ? errno : 0;
163	trp->tr_tag = fmd_ntz32(tag);
164
165	if (fmd.d_fmd_debug & FMD_DBG_TRACE)
166		fmd_vdprintf(tag, format, ap);
167
168	(void) vsnprintf(trp->tr_msg, sizeof (trp->tr_msg), format, ap);
169	p = &trp->tr_msg[strlen(trp->tr_msg)];
170	if (p > trp->tr_msg && p[-1] == '\n')
171		p[-1] = '\0';
172
173	if (tbp->tb_ptr != tbp->tb_end)
174		tbp->tb_ptr = (void *)((uintptr_t)tbp->tb_ptr + tbp->tb_size);
175	else
176		tbp->tb_ptr = tbp->tb_buf;
177
178	tbp->tb_depth--;
179	return (trp);
180}
181