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 2008 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/*
30 * Includes
31 */
32
33#ifndef DEBUG
34#define	NDEBUG	1
35#endif
36
37#include <assert.h>
38#include <limits.h>
39#include <values.h>
40#include <stdio.h>
41#include <string.h>
42#include <unistd.h>
43#include <stdlib.h>
44#include <sys/types.h>
45#include <sys/stat.h>
46#include <fcntl.h>
47#include <dlfcn.h>
48#include <sys/mman.h>
49#include <sys/param.h>
50
51#include <thread.h>
52#include <sys/lwp.h>
53#include <errno.h>
54
55#include "tnf_trace.h"
56
57
58/*
59 * Defines
60 */
61#define	TNF_FILE_MODE 	(S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH)
62
63/*
64 * Declarations
65 */
66
67extern void thr_probe_setup(void *);
68#pragma weak thr_probe_setup
69
70/*
71 * Globals
72 */
73
74static TNFW_B_CONTROL __tnfw_b_control_local = {
75	TNFW_B_NOBUFFER,
76	NULL,
77	_tnf_trace_initialize,
78	_tnf_fork_thread_setup,
79	NULL
80};
81
82TNFW_B_CONTROL *_tnfw_b_control = &__tnfw_b_control_local;
83
84static char    *file_start;
85
86/*
87 * Two Project Private Interfaces between prex and libtnfprobe -
88 * tnf_trace_file_name and tnf_trace_file_size (three now ...)
89 */
90char		tnf_trace_file_name[MAXPATHLEN] = "";
91uint_t		tnf_trace_file_size = 4194304;	/* 4 Meg */
92uint_t		tnf_trace_file_min = (128 * 1024);
93
94tnf_ops_t	tnf_trace_initial_tpd = {
95	TNF_ALLOC_REUSABLE,	/* mode			 */
96	tnfw_b_alloc,		/* alloc		 */
97	tnfw_b_xcommit,		/* commit		 */
98	tnfw_b_xabort,		/* rollback		 */
99	{
100		B_FALSE		/* tnfw_w_initialized	 */
101		/* rest of struct is null */
102	},
103	0			/* busy			 */
104};
105
106/*
107 * tnf_process_enable: exported API to turn on tracing for the process
108 *			(on by default).
109 */
110void
111tnf_process_enable(void)
112{
113	TNFW_B_UNSET_STOPPED(_tnfw_b_control->tnf_state);
114}
115
116/*
117 * tnf_process_disable: exported API to turn off tracing for the process.
118 */
119void
120tnf_process_disable(void)
121{
122	TNFW_B_SET_STOPPED(_tnfw_b_control->tnf_state);
123}
124
125/*
126 * _tnf_trace_initialize
127 *	prex is responsible for creating and zeroing the trace file.  So,
128 *	this routine expects the file to be there.  It does try to handle
129 *	the case where prex (run as root) for probing a setuid root program
130 *	created the trace file as root.  But, by the time the first probe is
131 *	hit (and this function is called), the program has reduced it's
132 *	privilege to its real user id - so the open fails.  In this case,
133 *	this function unlinks the trace file and creates it again with its
134 *	current user id.  The unlink can fail if the user does not have
135 *	write permission in the directory where the trace file is - if so,
136 *	tracing is set to broken.
137 */
138int
139_tnf_trace_initialize(void)
140{
141	int		fd;
142	int		created_file = 0;
143	static mutex_t 	init_mutex = DEFAULTMUTEX;
144
145	/*
146	 * if this is a MT program and the primordial thread hasn't been
147	 * setup yet, can't start tracing yet - THREAD_REG hasn't been
148	 * initialized, so we can't call open() in libthread.
149	 */
150
151	/*
152	 * Use dlsym to check for the present of thr_probe_setup.
153	 */
154
155	if ((((int(*)())dlsym(RTLD_DEFAULT, "thr_probe_setup")) != NULL) &&
156	    (thr_main() == -1)) {
157		return (0);
158	}
159
160	/*
161	 * lock is needed to to prevent multiple threads from
162	 * mmapping the file.
163	 */
164	mutex_lock(&init_mutex);
165	if (_tnfw_b_control->tnf_state != TNFW_B_NOBUFFER) {
166		mutex_unlock(&init_mutex);
167		return (1);
168	}
169
170	_tnfw_b_control->tnf_pid = getpid();
171	assert(tnf_trace_file_name[0] != '\0');
172	fd = open(tnf_trace_file_name, O_RDWR, TNF_FILE_MODE);
173	if (fd < 0) {
174		if (errno == EACCES) {
175			/*
176			 * fix for bug 1197494: permission denied when
177			 * trying to open the file - happens for setuid root
178			 * programs - prex creates the file with root ownership
179			 */
180			if (unlink(tnf_trace_file_name) == -1) {
181				goto SetBroken;
182			}
183			/* try creating it rather than opening it */
184			fd = open(tnf_trace_file_name,
185			    O_CREAT | O_RDWR | O_TRUNC, TNF_FILE_MODE);
186			if (fd < 0) {
187				goto SetBroken;
188			}
189			/*
190			 * expand file to needed size - ftruncate is not
191			 * portable, hence using lseek + write.
192			 */
193			if (lseek(fd, tnf_trace_file_size-1, SEEK_SET) == -1) {
194				goto SetBroken;
195			}
196			if (write(fd, "", 1) != 1) {
197				goto SetBroken;
198			}
199			created_file = 1;
200		} else {
201			goto SetBroken;
202		}
203	}
204
205	/* mmap the file */
206	if ((file_start = mmap(0, tnf_trace_file_size,
207	    PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0)) == (caddr_t)-1) {
208		goto SetBroken;
209	}
210	if (created_file == 1) {
211		/* explicitly zero the file XXX - performance problem */
212		(void) memset(file_start, 0, tnf_trace_file_size);
213	}
214	_tnfw_b_control->tnf_buffer = file_start;
215
216	if (tnfw_b_init_buffer(file_start, tnf_trace_file_size / TNF_BLOCK_SIZE,
217	    TNF_BLOCK_SIZE, B_TRUE) != TNFW_B_OK) {
218		goto SetBroken;
219	}
220
221	/* successful return */
222	_tnfw_b_control->tnf_state = TNFW_B_RUNNING;
223	mutex_unlock(&init_mutex);
224	return (1);
225
226SetBroken:
227	_tnfw_b_control->tnf_state = TNFW_B_BROKEN;
228	mutex_unlock(&init_mutex);
229	return (0);
230
231}
232
233/*
234 * _tnf_sched_init
235 */
236
237void
238_tnf_sched_init(tnf_schedule_t *sched, hrtime_t t)
239{
240	thread_t tid = 0;
241
242	sched->time_base = t;
243	/* thr_self() is stubbed out by libc for a non-threaded pgm */
244	tid = thr_self();
245	sched->tid = tid;
246	sched->lwpid = _lwp_self();
247	sched->pid = getpid();
248}
249