src/common/logging.h

   1 /*
   2  * SPDX-License-Identifier: LGPL-2.1-only
   3  *
   4  * Copyright (C) 2009 Pierre-Marc Fournier
   5  * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   6  */
   7
   8 #ifndef _UST_COMMON_LOGGING_H
   9 #define _UST_COMMON_LOGGING_H
  10
  11 #include <string.h>
  12 #include <sys/types.h>
  13 #include <errno.h>
  14 #include <stdarg.h>
  15 #include <stdbool.h>
  16 #include <stdio.h>
  17
  18 #include <lttng/ust-utils.h>
  19 #include <urcu/compiler.h>
  20 #include <urcu/system.h>
  21
  22 #include "common/patient.h"
  23 #include "common/compat/tid.h"
  24 #include "common/safe-snprintf.h"
  25
  26 enum lttng_ust_log_level {
  27         LTTNG_UST_LOG_LEVEL_UNKNOWN = 0,
  28         LTTNG_UST_LOG_LEVEL_SILENT,
  29         LTTNG_UST_LOG_LEVEL_DEBUG,
  30 };
  31
  32 enum 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
  38 extern int lttng_ust_log_level                  /* enum lttng_ust_log_level */
  39         __attribute__((visibility("hidden")));
  40
  41 extern int lttng_ust_log_critical_action                /* enum lttng_ust_log_critical_action */
  42         __attribute__((visibility("hidden")));
  43
  44 /*
  45  * Initialize the global log level from the "LTTNG_UST_DEBUG" environment
  46  * variable and the global log critical action from "LTTNG_UST_ABORT_ON_CRITICAL".
  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.
  51  */
  52 void lttng_ust_logging_init(void)
  53         __attribute__((visibility("hidden")));
  54
  55 #ifdef LTTNG_UST_DEBUG
  56 static inline
  57 bool lttng_ust_logging_debug_enabled(void)
  58 {
  59         return true;
  60 }
  61 #else /* #ifdef LTTNG_UST_DEBUG */
  62 static inline
  63 bool lttng_ust_logging_debug_enabled(void)
  64 {
  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. */
  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         }
  74
  75         return current_log_level == LTTNG_UST_LOG_LEVEL_DEBUG;
  76 }
  77 #endif /* #ifdef LTTNG_UST_DEBUG */
  78
  79 #ifdef LTTNG_UST_ABORT_ON_CRITICAL
  80 static inline
  81 bool lttng_ust_logging_abort_on_critical_enabled(void)
  82 {
  83         return true;
  84 }
  85 #else /* #ifdef LTTNG_UST_ABORT_ON_CRITICAL */
  86 static inline
  87 bool 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
 103 /*
 104  * The default component for log statements.
 105  */
 106 #ifndef UST_COMPONENT
 107 #define UST_COMPONENT libust
 108 #endif
 109
 110 #define LTTNG_UST_LOG_MAX_LEN   512
 111
 112 /*
 113  * We sometimes print in the tracing path, and tracing can occur in
 114  * signal handlers, so we must use a print method which is signal safe.
 115  */
 116 /* Can't use dynamic allocation. Limit ourselves to LTTNG_UST_LOG_MAX_LEN chars. */
 117 /* Add end of string in case of buffer overflow. */
 118 #define sigsafe_print_err(fmt, args...)                                 \
 119 do {                                                                    \
 120         if (lttng_ust_logging_debug_enabled()) {                        \
 121                 char ____buf[LTTNG_UST_LOG_MAX_LEN];                    \
 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;                       \
 127                 ust_patient_write(STDERR_FILENO, ____buf, strlen(____buf)); \
 128                 errno = ____saved_errno;        /* signal-safety */     \
 129                 fflush(stderr);                                         \
 130         }                                                               \
 131 } while (0)
 132
 133 #define LTTNG_UST_STR_COMPONENT lttng_ust_stringify(UST_COMPONENT)
 134
 135 #define ERRMSG(fmt, args...)                    \
 136         do {                                    \
 137                 sigsafe_print_err(LTTNG_UST_STR_COMPONENT "[%ld/%ld]: " fmt " (in %s() at " __FILE__ ":" lttng_ust_stringify(__LINE__) ")\n", \
 138                 (long) getpid(),                \
 139                 (long) lttng_gettid(),          \
 140                 ## args, __func__);             \
 141         } while(0)
 142
 143
 144 #define DBG(fmt, args...)       ERRMSG(fmt, ## args)
 145 #define DBG_raw(fmt, args...)   sigsafe_print_err(fmt, ## args)
 146 #define WARN(fmt, args...)      ERRMSG("Warning: " fmt, ## args)
 147 #define ERR(fmt, args...)       ERRMSG("Error: " fmt, ## args)
 148 #define CRIT(fmt, args...)                                              \
 149         do {                                                            \
 150                 ERRMSG("Critical: " fmt, ## args);                      \
 151                 if (lttng_ust_logging_abort_on_critical_enabled()) {    \
 152                         abort();                                        \
 153                 }                                                       \
 154         } while(0)
 155
 156 #if !defined(__GLIBC__) || ((_POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600) && !defined(_GNU_SOURCE))
 157 /*
 158  * Version using XSI strerror_r.
 159  */
 160 #define PERROR(call, args...)                                           \
 161         do {                                                            \
 162                 if (lttng_ust_logging_debug_enabled()) {                \
 163                         char perror_buf[200] = "Error in strerror_r()"; \
 164                         strerror_r(errno, perror_buf,                   \
 165                                         sizeof(perror_buf));            \
 166                         ERRMSG("Error: " call ": %s", ## args,          \
 167                                         perror_buf);                    \
 168                 }                                                       \
 169         } while(0)
 170 #else
 171 /*
 172  * Version using GNU strerror_r, for linux with appropriate defines.
 173  */
 174 #define PERROR(call, args...)                                           \
 175         do {                                                            \
 176                 if (lttng_ust_logging_debug_enabled()) {                \
 177                         char *perror_buf;                               \
 178                         char perror_tmp[200];                           \
 179                         perror_buf = strerror_r(errno, perror_tmp,      \
 180                                         sizeof(perror_tmp));            \
 181                         ERRMSG("Error: " call ": %s", ## args,          \
 182                                         perror_buf);                    \
 183                 }                                                       \
 184         } while(0)
 185 #endif
 186
 187 #define BUG_ON(condition)                                       \
 188         do {                                                    \
 189                 if (caa_unlikely(condition))                    \
 190                         ERR("condition not respected (BUG) on line %s:%d", __FILE__, __LINE__); \
 191         } while(0)
 192 #define WARN_ON(condition)                                      \
 193         do {                                                    \
 194                 if (caa_unlikely(condition))                    \
 195                         WARN("condition not respected on line %s:%d", __FILE__, __LINE__); \
 196         } while(0)
 197 #define WARN_ON_ONCE(condition) WARN_ON(condition)
 198
 199 #endif /* _UST_COMMON_LOGGING_H */