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 <share.h>
  17 #include "lttng/ust-tid.h"
  18
  19 enum ust_loglevel {
  20         UST_LOGLEVEL_UNKNOWN = 0,
  21         UST_LOGLEVEL_NORMAL,
  22         UST_LOGLEVEL_DEBUG,
  23 };
  24
  25 extern volatile enum ust_loglevel ust_loglevel;
  26 void init_usterr(void);
  27
  28 #ifdef LTTNG_UST_DEBUG
  29 static inline int ust_debug(void)
  30 {
  31         return 1;
  32 }
  33 #else /* #ifdef LTTNG_UST_DEBUG */
  34 static inline int ust_debug(void)
  35 {
  36         return ust_loglevel == UST_LOGLEVEL_DEBUG;
  37 }
  38 #endif /* #else #ifdef LTTNG_UST_DEBUG */
  39
  40 #ifndef UST_COMPONENT
  41 //#error UST_COMPONENT is undefined
  42 #define UST_COMPONENT libust
  43 #endif
  44
  45 /* To stringify the expansion of a define */
  46 #define UST_XSTR(d) UST_STR(d)
  47 #define UST_STR(s) #s
  48
  49 #define USTERR_MAX_LEN  512
  50
  51 /* We sometimes print in the tracing path, and tracing can occur in
  52  * signal handlers, so we must use a print method which is signal safe.
  53  */
  54
  55 extern int ust_safe_snprintf(char *str, size_t n, const char *fmt, ...)
  56         __attribute__ ((format (printf, 3, 4)));
  57
  58 /* Can't use dynamic allocation. Limit ourselves to USTERR_MAX_LEN chars. */
  59 /* Add end of string in case of buffer overflow. */
  60 #define sigsafe_print_err(fmt, args...)                                 \
  61 do {                                                                    \
  62         if (ust_debug()) {                                              \
  63                 char ____buf[USTERR_MAX_LEN];                           \
  64                 int ____saved_errno;                                    \
  65                                                                         \
  66                 ____saved_errno = errno;        /* signal-safety */     \
  67                 ust_safe_snprintf(____buf, sizeof(____buf), fmt, ## args); \
  68                 ____buf[sizeof(____buf) - 1] = 0;                       \
  69                 patient_write(STDERR_FILENO, ____buf, strlen(____buf)); \
  70                 errno = ____saved_errno;        /* signal-safety */     \
  71                 fflush(stderr);                                         \
  72         }                                                               \
  73 } while (0)
  74
  75 #define UST_STR_COMPONENT UST_XSTR(UST_COMPONENT)
  76
  77 #define ERRMSG(fmt, args...)                    \
  78         do {                                    \
  79                 sigsafe_print_err(UST_STR_COMPONENT "[%ld/%ld]: " fmt " (in %s() at " __FILE__ ":" UST_XSTR(__LINE__) ")\n", \
  80                 (long) getpid(),                \
  81                 (long) lttng_gettid(),          \
  82                 ## args, __func__);             \
  83         } while(0)
  84
  85
  86 #define DBG(fmt, args...)       ERRMSG(fmt, ## args)
  87 #define DBG_raw(fmt, args...)   sigsafe_print_err(fmt, ## args)
  88 #define WARN(fmt, args...)      ERRMSG("Warning: " fmt, ## args)
  89 #define ERR(fmt, args...)       ERRMSG("Error: " fmt, ## args)
  90 #define BUG(fmt, args...)       ERRMSG("BUG: " fmt, ## args)
  91
  92 #if !defined(__GLIBC__) || ((_POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600) && !defined(_GNU_SOURCE))
  93 /*
  94  * Version using XSI strerror_r.
  95  */
  96 #define PERROR(call, args...)                                           \
  97         do {                                                            \
  98                 if (ust_debug()) {                                      \
  99                         char buf[200] = "Error in strerror_r()";        \
 100                         strerror_r(errno, buf, sizeof(buf));            \
 101                         ERRMSG("Error: " call ": %s", ## args, buf);    \
 102                 }                                                       \
 103         } while(0)
 104 #else
 105 /*
 106  * Version using GNU strerror_r, for linux with appropriate defines.
 107  */
 108 #define PERROR(call, args...)                                           \
 109         do {                                                            \
 110                 if (ust_debug()) {                                      \
 111                         char *buf;                                      \
 112                         char tmp[200];                                  \
 113                         buf = strerror_r(errno, tmp, sizeof(tmp));      \
 114                         ERRMSG("Error: " call ": %s", ## args, buf);    \
 115                 }                                                       \
 116         } while(0)
 117 #endif
 118
 119 #define BUG_ON(condition)                                       \
 120         do {                                                    \
 121                 if (caa_unlikely(condition))                    \
 122                         ERR("condition not respected (BUG) on line %s:%d", __FILE__, __LINE__); \
 123         } while(0)
 124 #define WARN_ON(condition)                                      \
 125         do {                                                    \
 126                 if (caa_unlikely(condition))                    \
 127                         WARN("condition not respected on line %s:%d", __FILE__, __LINE__); \
 128         } while(0)
 129 #define WARN_ON_ONCE(condition) WARN_ON(condition)
 130
 131 #endif /* _USTERR_SIGNAL_SAFE_H */