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