Fix: remove non-async-signal-safe fflush from ERR()
[lttng-ust.git] / src / common / logging.h
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5e96a467 1/*
c0c0989a 2 * SPDX-License-Identifier: LGPL-2.1-only
30ffe279 3 *
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4 * Copyright (C) 2009 Pierre-Marc Fournier
5 * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
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6 */
7
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8#ifndef _UST_COMMON_LOGGING_H
9#define _UST_COMMON_LOGGING_H
c0c0989a 10
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11#include <string.h>
12#include <sys/types.h>
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13#include <errno.h>
14#include <stdarg.h>
2b6f4374 15#include <stdbool.h>
30ffe279 16#include <stdio.h>
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17
18#include <lttng/ust-utils.h>
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19#include <urcu/compiler.h>
20#include <urcu/system.h>
c6e6343c 21
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22#include "common/patient.h"
23#include "common/compat/tid.h"
24#include "common/safe-snprintf.h"
30ffe279 25
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26enum lttng_ust_log_level {
27 LTTNG_UST_LOG_LEVEL_UNKNOWN = 0,
39313bf3 28 LTTNG_UST_LOG_LEVEL_SILENT,
c6e6343c 29 LTTNG_UST_LOG_LEVEL_DEBUG,
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30};
31
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32enum lttng_ust_log_critical_action {
33 LTTNG_UST_LOG_CRITICAL_ACTION_UNKNOWN = 0,
34 LTTNG_UST_LOG_CRITICAL_ACTION_NONE,
35 LTTNG_UST_LOG_CRITICAL_ACTION_ABORT,
36};
37
39313bf3 38extern int lttng_ust_log_level /* enum lttng_ust_log_level */
1d18d519 39 __attribute__((visibility("hidden")));
ddabe860 40
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41extern int lttng_ust_log_critical_action /* enum lttng_ust_log_critical_action */
42 __attribute__((visibility("hidden")));
43
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44/*
45 * Initialize the global log level from the "LTTNG_UST_DEBUG" environment
9ff107a9 46 * variable and the global log critical action from "LTTNG_UST_ABORT_ON_CRITICAL".
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47 *
48 * This could end up being called concurrently by multiple threads but doesn't
49 * require a mutex since the input is invariant across threads and the result
50 * will be the same.
39313bf3 51 */
9ff107a9 52void lttng_ust_logging_init(void)
1d18d519 53 __attribute__((visibility("hidden")));
5e96a467 54
7bdd21a4 55#ifdef LTTNG_UST_DEBUG
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56static inline
57bool lttng_ust_logging_debug_enabled(void)
7bdd21a4 58{
2b6f4374 59 return true;
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60}
61#else /* #ifdef LTTNG_UST_DEBUG */
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62static inline
63bool lttng_ust_logging_debug_enabled(void)
5e96a467 64{
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65 int current_log_level;
66
67 current_log_level = CMM_LOAD_SHARED(lttng_ust_log_level);
68
69 /* If the global log level is unknown, lazy-initialize it. */
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70 if (caa_unlikely(current_log_level == LTTNG_UST_LOG_LEVEL_UNKNOWN)) {
71 lttng_ust_logging_init();
72 current_log_level = CMM_LOAD_SHARED(lttng_ust_log_level);
73 }
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74
75 return current_log_level == LTTNG_UST_LOG_LEVEL_DEBUG;
5e96a467 76}
39313bf3 77#endif /* #ifdef LTTNG_UST_DEBUG */
5e96a467 78
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79#ifdef LTTNG_UST_ABORT_ON_CRITICAL
80static inline
81bool lttng_ust_logging_abort_on_critical_enabled(void)
82{
83 return true;
84}
85#else /* #ifdef LTTNG_UST_ABORT_ON_CRITICAL */
86static inline
87bool lttng_ust_logging_abort_on_critical_enabled(void)
88{
89 int current_log_critical_action;
90
91 current_log_critical_action = CMM_LOAD_SHARED(lttng_ust_log_critical_action);
92
93 /* If the global log critical action is unknown, lazy-initialize it. */
94 if (caa_unlikely(current_log_critical_action == LTTNG_UST_LOG_CRITICAL_ACTION_UNKNOWN)) {
95 lttng_ust_logging_init();
96 current_log_critical_action = CMM_LOAD_SHARED(lttng_ust_log_critical_action);
97 }
98
99 return current_log_critical_action == LTTNG_UST_LOG_CRITICAL_ACTION_ABORT;
100}
101#endif /* #ifdef LTTNG_UST_ABORT_ON_CRITICAL */
102
2b6f4374 103/*
9ff107a9 104 * The default component for log statements.
2b6f4374 105 */
30ffe279 106#ifndef UST_COMPONENT
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107#define UST_COMPONENT libust
108#endif
109
c6e6343c 110#define LTTNG_UST_LOG_MAX_LEN 512
37ed587a 111
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112/*
113 * We sometimes print in the tracing path, and tracing can occur in
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114 * signal handlers, so we must use a print method which is signal safe.
115 */
c6e6343c 116/* Can't use dynamic allocation. Limit ourselves to LTTNG_UST_LOG_MAX_LEN chars. */
648bb724 117/* Add end of string in case of buffer overflow. */
5e96a467 118#define sigsafe_print_err(fmt, args...) \
648bb724 119do { \
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120 if (lttng_ust_logging_debug_enabled()) { \
121 char ____buf[LTTNG_UST_LOG_MAX_LEN]; \
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122 int ____saved_errno; \
123 \
124 ____saved_errno = errno; /* signal-safety */ \
125 ust_safe_snprintf(____buf, sizeof(____buf), fmt, ## args); \
126 ____buf[sizeof(____buf) - 1] = 0; \
516d12da 127 ust_patient_write(STDERR_FILENO, ____buf, strlen(____buf)); \
7bdd21a4 128 errno = ____saved_errno; /* signal-safety */ \
7bdd21a4 129 } \
648bb724 130} while (0)
30ffe279 131
c6e6343c 132#define LTTNG_UST_STR_COMPONENT lttng_ust_stringify(UST_COMPONENT)
30ffe279 133
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134#define ERRMSG(fmt, args...) \
135 do { \
c6e6343c 136 sigsafe_print_err(LTTNG_UST_STR_COMPONENT "[%ld/%ld]: " fmt " (in %s() at " __FILE__ ":" lttng_ust_stringify(__LINE__) ")\n", \
5e96a467 137 (long) getpid(), \
0f029713 138 (long) lttng_gettid(), \
5e96a467 139 ## args, __func__); \
5e96a467 140 } while(0)
30ffe279 141
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142
143#define DBG(fmt, args...) ERRMSG(fmt, ## args)
144#define DBG_raw(fmt, args...) sigsafe_print_err(fmt, ## args)
145#define WARN(fmt, args...) ERRMSG("Warning: " fmt, ## args)
146#define ERR(fmt, args...) ERRMSG("Error: " fmt, ## args)
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147#define CRIT(fmt, args...) \
148 do { \
149 ERRMSG("Critical: " fmt, ## args); \
150 if (lttng_ust_logging_abort_on_critical_enabled()) { \
151 abort(); \
152 } \
153 } while(0)
30ffe279 154
b52af467 155#if !defined(__GLIBC__) || ((_POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600) && !defined(_GNU_SOURCE))
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156/*
157 * Version using XSI strerror_r.
158 */
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159#define PERROR(call, args...) \
160 do { \
c6e6343c 161 if (lttng_ust_logging_debug_enabled()) { \
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162 char perror_buf[200] = "Error in strerror_r()"; \
163 strerror_r(errno, perror_buf, \
164 sizeof(perror_buf)); \
165 ERRMSG("Error: " call ": %s", ## args, \
166 perror_buf); \
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167 } \
168 } while(0)
30ffe279 169#else
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170/*
171 * Version using GNU strerror_r, for linux with appropriate defines.
172 */
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173#define PERROR(call, args...) \
174 do { \
c6e6343c 175 if (lttng_ust_logging_debug_enabled()) { \
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176 char *perror_buf; \
177 char perror_tmp[200]; \
178 perror_buf = strerror_r(errno, perror_tmp, \
179 sizeof(perror_tmp)); \
180 ERRMSG("Error: " call ": %s", ## args, \
181 perror_buf); \
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182 } \
183 } while(0)
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184#endif
185
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186#define BUG_ON(condition) \
187 do { \
b5a3dfa5 188 if (caa_unlikely(condition)) \
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189 ERR("condition not respected (BUG) on line %s:%d", __FILE__, __LINE__); \
190 } while(0)
191#define WARN_ON(condition) \
192 do { \
b5a3dfa5 193 if (caa_unlikely(condition)) \
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194 WARN("condition not respected on line %s:%d", __FILE__, __LINE__); \
195 } while(0)
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196#define WARN_ON_ONCE(condition) WARN_ON(condition)
197
c6e6343c 198#endif /* _UST_COMMON_LOGGING_H */
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