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
  20 #include "common/patient.h"
  21 #include "common/compat/tid.h"
  22 #include "common/safe-snprintf.h"
  23
  24 enum lttng_ust_log_level {
  25         LTTNG_UST_LOG_LEVEL_UNKNOWN = 0,
  26         LTTNG_UST_LOG_LEVEL_NORMAL,
  27         LTTNG_UST_LOG_LEVEL_DEBUG,
  28 };
  29
  30 extern volatile enum lttng_ust_log_level lttng_ust_log_level
  31         __attribute__((visibility("hidden")));
  32
  33 void lttng_ust_logging_init(void)
  34         __attribute__((visibility("hidden")));
  35
  36 #ifdef LTTNG_UST_DEBUG
  37 static inline bool lttng_ust_logging_debug_enabled(void)
  38 {
  39         return true;
  40 }
  41 #else /* #ifdef LTTNG_UST_DEBUG */
  42 static inline bool lttng_ust_logging_debug_enabled(void)
  43 {
  44         return lttng_ust_log_level == LTTNG_UST_LOG_LEVEL_DEBUG;
  45 }
  46 #endif /* #else #ifdef LTTNG_UST_DEBUG */
  47
  48 /*
  49  * The default component for error messages.
  50  */
  51 #ifndef UST_COMPONENT
  52 #define UST_COMPONENT libust
  53 #endif
  54
  55 #define LTTNG_UST_LOG_MAX_LEN   512
  56
  57 /*
  58  * We sometimes print in the tracing path, and tracing can occur in
  59  * signal handlers, so we must use a print method which is signal safe.
  60  */
  61 /* Can't use dynamic allocation. Limit ourselves to LTTNG_UST_LOG_MAX_LEN chars. */
  62 /* Add end of string in case of buffer overflow. */
  63 #define sigsafe_print_err(fmt, args...)                                 \
  64 do {                                                                    \
  65         if (lttng_ust_logging_debug_enabled()) {                        \
  66                 char ____buf[LTTNG_UST_LOG_MAX_LEN];                    \
  67                 int ____saved_errno;                                    \
  68                                                                         \
  69                 ____saved_errno = errno;        /* signal-safety */     \
  70                 ust_safe_snprintf(____buf, sizeof(____buf), fmt, ## args); \
  71                 ____buf[sizeof(____buf) - 1] = 0;                       \
  72                 ust_patient_write(STDERR_FILENO, ____buf, strlen(____buf)); \
  73                 errno = ____saved_errno;        /* signal-safety */     \
  74                 fflush(stderr);                                         \
  75         }                                                               \
  76 } while (0)
  77
  78 #define LTTNG_UST_STR_COMPONENT lttng_ust_stringify(UST_COMPONENT)
  79
  80 #define ERRMSG(fmt, args...)                    \
  81         do {                                    \
  82                 sigsafe_print_err(LTTNG_UST_STR_COMPONENT "[%ld/%ld]: " fmt " (in %s() at " __FILE__ ":" lttng_ust_stringify(__LINE__) ")\n", \
  83                 (long) getpid(),                \
  84                 (long) lttng_gettid(),          \
  85                 ## args, __func__);             \
  86         } while(0)
  87
  88
  89 #define DBG(fmt, args...)       ERRMSG(fmt, ## args)
  90 #define DBG_raw(fmt, args...)   sigsafe_print_err(fmt, ## args)
  91 #define WARN(fmt, args...)      ERRMSG("Warning: " fmt, ## args)
  92 #define ERR(fmt, args...)       ERRMSG("Error: " fmt, ## args)
  93 #define BUG(fmt, args...)       ERRMSG("BUG: " fmt, ## args)
  94
  95 #if !defined(__GLIBC__) || ((_POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600) && !defined(_GNU_SOURCE))
  96 /*
  97  * Version using XSI strerror_r.
  98  */
  99 #define PERROR(call, args...)                                           \
 100         do {                                                            \
 101                 if (lttng_ust_logging_debug_enabled()) {                \
 102                         char perror_buf[200] = "Error in strerror_r()"; \
 103                         strerror_r(errno, perror_buf,                   \
 104                                         sizeof(perror_buf));            \
 105                         ERRMSG("Error: " call ": %s", ## args,          \
 106                                         perror_buf);                    \
 107                 }                                                       \
 108         } while(0)
 109 #else
 110 /*
 111  * Version using GNU strerror_r, for linux with appropriate defines.
 112  */
 113 #define PERROR(call, args...)                                           \
 114         do {                                                            \
 115                 if (lttng_ust_logging_debug_enabled()) {                \
 116                         char *perror_buf;                               \
 117                         char perror_tmp[200];                           \
 118                         perror_buf = strerror_r(errno, perror_tmp,      \
 119                                         sizeof(perror_tmp));            \
 120                         ERRMSG("Error: " call ": %s", ## args,          \
 121                                         perror_buf);                    \
 122                 }                                                       \
 123         } while(0)
 124 #endif
 125
 126 #define BUG_ON(condition)                                       \
 127         do {                                                    \
 128                 if (caa_unlikely(condition))                    \
 129                         ERR("condition not respected (BUG) on line %s:%d", __FILE__, __LINE__); \
 130         } while(0)
 131 #define WARN_ON(condition)                                      \
 132         do {                                                    \
 133                 if (caa_unlikely(condition))                    \
 134                         WARN("condition not respected on line %s:%d", __FILE__, __LINE__); \
 135         } while(0)
 136 #define WARN_ON_ONCE(condition) WARN_ON(condition)
 137
 138 #endif /* _UST_COMMON_LOGGING_H */