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#pragma ident	"%Z%%M%	%I%	%E% SMI"
28
29#include <sys/types.h>
30#include <sys/sysmacros.h>
31
32#include <ucontext.h>
33#include <strings.h>
34#include <stdio.h>
35#include <errno.h>
36
37#include <fmd_trace.h>
38#include <fmd_alloc.h>
39#include <fmd_subr.h>
40#include <fmd_conf.h>
41#include <fmd.h>
42
43fmd_tracebuf_t *
44fmd_trace_create(void)
45{
46	fmd_tracebuf_t *tbp = fmd_zalloc(sizeof (fmd_tracebuf_t), FMD_SLEEP);
47	size_t bufsize;
48
49	(void) fmd_conf_getprop(fmd.d_conf, "trace.frames", &tbp->tb_frames);
50	(void) fmd_conf_getprop(fmd.d_conf, "trace.recs", &tbp->tb_recs);
51
52	/*
53	 * We require 8-byte alignment of fmd_tracerec_t to store hrtime_t's.
54	 * Since the trailing flexible array member is of type uintptr_t, we
55	 * may need to allocate an additional element if we are compiling
56	 * 32-bit; otherwise uintptr_t is 8 bytes so any value of tb_frames is
57	 * acceptable.
58	 *
59	 * tb_frames includes the first element, whose size is reflected in
60	 * sizeof (fmd_tracerec_t).  Therefore, if fmd_tracerec_t's size is
61	 * 0 mod 8, we must be sure the total number of frames is odd.
62	 * Otherwise, we need at least one extra frame, so the total count
63	 * must be even.  This will continue to work even if the sizes or
64	 * types of other fmd_tracerec_t members are changed.
65	 */
66#ifdef _ILP32
67	/*CONSTCOND*/
68	if (sizeof (fmd_tracerec_t) % sizeof (hrtime_t) == 0)
69		tbp->tb_frames = (tbp->tb_frames & ~1UL) + 1;
70	else
71		tbp->tb_frames = P2ROUNDUP(tbp->tb_frames, 2);
72#endif
73	tbp->tb_size = sizeof (fmd_tracerec_t) +
74	    sizeof (uintptr_t) * (MAX(tbp->tb_frames, 1) - 1);
75
76	bufsize = tbp->tb_size * tbp->tb_recs;
77
78	tbp->tb_buf = fmd_zalloc(bufsize, FMD_SLEEP);
79	tbp->tb_end = (void *)((uintptr_t)tbp->tb_buf + bufsize - tbp->tb_size);
80	tbp->tb_ptr = tbp->tb_buf;
81
82	return (tbp);
83}
84
85void
86fmd_trace_destroy(fmd_tracebuf_t *tbp)
87{
88	fmd_free(tbp->tb_buf, tbp->tb_size * tbp->tb_recs);
89	fmd_free(tbp, sizeof (fmd_tracebuf_t));
90}
91
92/*
93 * Callback for walkcontext(3C) to store the stack trace.  We use tr_tag below
94 * to store the maximum value of depth that is permitted so we can use it here.
95 */
96/*ARGSUSED*/
97static int
98fmd_trace_frame(uintptr_t pc, int sig, fmd_tracerec_t *trp)
99{
100	trp->tr_stack[trp->tr_depth++] = pc;
101	return (trp->tr_depth >= trp->tr_tag);
102}
103
104/*ARGSUSED*/
105fmd_tracerec_t *
106fmd_trace_none(fmd_tracebuf_t *tbp, uint_t tag, const char *format, va_list ap)
107{
108	return (NULL);
109}
110
111fmd_tracerec_t *
112fmd_trace_lite(fmd_tracebuf_t *tbp, uint_t tag, const char *format, va_list ap)
113{
114	hrtime_t time = gethrtime();
115	fmd_tracerec_t *trp = tbp->tb_ptr;
116	char *p;
117
118	if (tbp->tb_depth++ != 0) {
119		tbp->tb_depth--;
120		return (NULL);
121	}
122
123	trp->tr_time = time;
124	trp->tr_file = NULL;
125	trp->tr_line = 0;
126	trp->tr_errno = (tag == FMD_DBG_ERR) ? errno : 0;
127	trp->tr_tag = fmd_ntz32(tag);
128
129	(void) vsnprintf(trp->tr_msg, sizeof (trp->tr_msg), format, ap);
130	p = &trp->tr_msg[strlen(trp->tr_msg)];
131	if (p > trp->tr_msg && p[-1] == '\n')
132		p[-1] = '\0';
133
134	if (tbp->tb_ptr != tbp->tb_end)
135		tbp->tb_ptr = (void *)((uintptr_t)tbp->tb_ptr + tbp->tb_size);
136	else
137		tbp->tb_ptr = tbp->tb_buf;
138
139	tbp->tb_depth--;
140	return (trp);
141}
142
143fmd_tracerec_t *
144fmd_trace_full(fmd_tracebuf_t *tbp, uint_t tag, const char *format, va_list ap)
145{
146	hrtime_t time = gethrtime();
147	fmd_tracerec_t *trp = tbp->tb_ptr;
148	ucontext_t uc;
149	char *p;
150
151	if (tbp->tb_depth++ != 0) {
152		tbp->tb_depth--;
153		return (NULL);
154	}
155
156	(void) getcontext(&uc);
157	trp->tr_tag = tbp->tb_frames; /* for use by fmd_trace_frame() */
158	(void) walkcontext(&uc, (int (*)())fmd_trace_frame, trp);
159
160	trp->tr_time = time;
161	trp->tr_file = NULL;
162	trp->tr_line = 0;
163	trp->tr_errno = (tag == FMD_DBG_ERR) ? errno : 0;
164	trp->tr_tag = fmd_ntz32(tag);
165
166	if (fmd.d_fmd_debug & FMD_DBG_TRACE)
167		fmd_vdprintf(tag, format, ap);
168
169	(void) vsnprintf(trp->tr_msg, sizeof (trp->tr_msg), format, ap);
170	p = &trp->tr_msg[strlen(trp->tr_msg)];
171	if (p > trp->tr_msg && p[-1] == '\n')
172		p[-1] = '\0';
173
174	if (tbp->tb_ptr != tbp->tb_end)
175		tbp->tb_ptr = (void *)((uintptr_t)tbp->tb_ptr + tbp->tb_size);
176	else
177		tbp->tb_ptr = tbp->tb_buf;
178
179	tbp->tb_depth--;
180	return (trp);
181}
182