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