1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
|
/*
* Copyright (C) 2012 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <pthread.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <cutils/atomic.h>
#include <cutils/compiler.h>
#include <cutils/properties.h>
#include <cutils/trace.h>
#define LOG_TAG "cutils-trace"
#include <cutils/log.h>
volatile int32_t atrace_is_ready = 0;
int atrace_marker_fd = -1;
uint64_t atrace_enabled_tags = ATRACE_TAG_NOT_READY;
static bool atrace_is_debuggable = false;
static volatile int32_t atrace_is_enabled = 1;
static pthread_once_t atrace_once_control = PTHREAD_ONCE_INIT;
static pthread_mutex_t atrace_tags_mutex = PTHREAD_MUTEX_INITIALIZER;
// Set whether this process is debuggable, which determines whether
// application-level tracing is allowed when the ro.debuggable system property
// is not set to '1'.
void atrace_set_debuggable(bool debuggable)
{
atrace_is_debuggable = debuggable;
atrace_update_tags();
}
// Set whether tracing is enabled in this process. This is used to prevent
// the Zygote process from tracing.
void atrace_set_tracing_enabled(bool enabled)
{
android_atomic_release_store(enabled ? 1 : 0, &atrace_is_enabled);
atrace_update_tags();
}
// Check whether the given command line matches one of the comma-separated
// values listed in the app_cmdlines property.
static bool atrace_is_cmdline_match(const char* cmdline)
{
char value[PROPERTY_VALUE_MAX];
char* start = value;
property_get("debug.atrace.app_cmdlines", value, "");
while (start != NULL) {
char* end = strchr(start, ',');
if (end != NULL) {
*end = '\0';
end++;
}
if (strcmp(cmdline, start) == 0) {
return true;
}
start = end;
}
return false;
}
// Determine whether application-level tracing is enabled for this process.
static bool atrace_is_app_tracing_enabled()
{
bool sys_debuggable = false;
bool proc_debuggable = false;
char value[PROPERTY_VALUE_MAX];
bool result = false;
// Check whether the system is debuggable.
property_get("ro.debuggable", value, "0");
if (value[0] == '1') {
sys_debuggable = true;
}
if (sys_debuggable || atrace_is_debuggable) {
// Check whether tracing is enabled for this process.
FILE * file = fopen("/proc/self/cmdline", "r");
if (file) {
char cmdline[4096];
if (fgets(cmdline, sizeof(cmdline), file)) {
result = atrace_is_cmdline_match(cmdline);
} else {
ALOGE("Error reading cmdline: %s (%d)", strerror(errno), errno);
}
fclose(file);
} else {
ALOGE("Error opening /proc/self/cmdline: %s (%d)", strerror(errno),
errno);
}
}
return result;
}
// Read the sysprop and return the value tags should be set to
static uint64_t atrace_get_property()
{
char value[PROPERTY_VALUE_MAX];
char *endptr;
uint64_t tags;
property_get("debug.atrace.tags.enableflags", value, "0");
errno = 0;
tags = strtoull(value, &endptr, 0);
if (value[0] == '\0' || *endptr != '\0') {
ALOGE("Error parsing trace property: Not a number: %s", value);
return 0;
} else if (errno == ERANGE || tags == ULLONG_MAX) {
ALOGE("Error parsing trace property: Number too large: %s", value);
return 0;
}
// Only set the "app" tag if this process was selected for app-level debug
// tracing.
if (atrace_is_app_tracing_enabled()) {
tags |= ATRACE_TAG_APP;
} else {
tags &= ~ATRACE_TAG_APP;
}
return (tags | ATRACE_TAG_ALWAYS) & ATRACE_TAG_VALID_MASK;
}
// Update tags if tracing is ready. Useful as a sysprop change callback.
void atrace_update_tags()
{
uint64_t tags;
if (CC_UNLIKELY(android_atomic_acquire_load(&atrace_is_ready))) {
if (android_atomic_acquire_load(&atrace_is_enabled)) {
tags = atrace_get_property();
pthread_mutex_lock(&atrace_tags_mutex);
atrace_enabled_tags = tags;
pthread_mutex_unlock(&atrace_tags_mutex);
} else {
// Tracing is disabled for this process, so we simply don't
// initialize the tags.
pthread_mutex_lock(&atrace_tags_mutex);
atrace_enabled_tags = ATRACE_TAG_NOT_READY;
pthread_mutex_unlock(&atrace_tags_mutex);
}
}
}
static void atrace_init_once()
{
atrace_marker_fd = open("/sys/kernel/debug/tracing/trace_marker", O_WRONLY);
if (atrace_marker_fd == -1) {
ALOGE("Error opening trace file: %s (%d)", strerror(errno), errno);
atrace_enabled_tags = 0;
goto done;
}
atrace_enabled_tags = atrace_get_property();
done:
android_atomic_release_store(1, &atrace_is_ready);
}
void atrace_setup()
{
pthread_once(&atrace_once_control, atrace_init_once);
}
|
