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
67 extern void thr_probe_setup(void *);
68 #pragma weak thr_probe_setup
69
70 /*
71 * Globals
72 */
73
74 static 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
82 TNFW_B_CONTROL *_tnfw_b_control = &__tnfw_b_control_local;
83
84 static 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 */
90 char tnf_trace_file_name[MAXPATHLEN] = "";
91 uint_t tnf_trace_file_size = 4194304; /* 4 Meg */
92 uint_t tnf_trace_file_min = (128 * 1024);
93
94 tnf_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 */
110 void
tnf_process_enable(void)111 tnf_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 */
119 void
tnf_process_disable(void)120 tnf_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 */
138 int
_tnf_trace_initialize(void)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
226 SetBroken:
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
237 void
_tnf_sched_init(tnf_schedule_t * sched,hrtime_t t)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