include/lttng/usterr-signal-safe.h

   1 #ifndef _USTERR_SIGNAL_SAFE_H
   2 #define _USTERR_SIGNAL_SAFE_H
   3
   4 /*
   5  * Copyright (C) 2009  Pierre-Marc Fournier
   6  * Copyright (C) 2011  Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   7  *
   8  * This library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; version 2.1 of
  11  * the License.
  12  *
  13  * This library is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this library; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
  21  */
  22
  23 #include <string.h>
  24 #include <sys/types.h>
  25 #include <sys/syscall.h>
  26 #include <errno.h>
  27 #include <stdarg.h>
  28 #include <stdio.h>
  29
  30 #include <lttng/core.h>
  31 #include <lttng/share.h>
  32
  33 enum ust_loglevel {
  34         UST_LOGLEVEL_UNKNOWN = 0,
  35         UST_LOGLEVEL_NORMAL,
  36         UST_LOGLEVEL_DEBUG,
  37 };
  38
  39 extern volatile enum ust_loglevel ust_loglevel;
  40 void init_usterr(void);
  41
  42 static inline int ust_debug(void)
  43 {
  44         return ust_loglevel == UST_LOGLEVEL_DEBUG;
  45 }
  46
  47 #ifndef UST_COMPONENT
  48 //#error UST_COMPONENT is undefined
  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 USTERR_MAX_LEN  512
  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
  62 extern int ust_safe_snprintf(char *str, size_t n, const char *fmt, ...)
  63         __attribute__ ((format (printf, 3, 4)));
  64
  65 static inline void __attribute__ ((format (printf, 1, 2)))
  66         __check_ust_safe_fmt(const char *fmt, ...)
  67 {
  68 }
  69
  70 /* Can't use dynamic allocation. Limit ourselves to USTERR_MAX_LEN chars. */
  71 /* Add end of string in case of buffer overflow. */
  72 #define sigsafe_print_err(fmt, args...)                                 \
  73 do {                                                                    \
  74         char ____buf[USTERR_MAX_LEN];                                   \
  75         int ____saved_errno;                                            \
  76         ____saved_errno = errno;        /* signal-safety */             \
  77         ust_safe_snprintf(____buf, sizeof(____buf), fmt, ## args);      \
  78         ____buf[sizeof(____buf) - 1] = 0;                               \
  79         patient_write(STDERR_FILENO, ____buf, strlen(____buf));         \
  80         errno = ____saved_errno;        /* signal-safety */             \
  81 } while (0)
  82
  83 #define UST_STR_COMPONENT UST_XSTR(UST_COMPONENT)
  84
  85 #define ERRMSG(fmt, args...)                    \
  86         do {                                    \
  87                 sigsafe_print_err(UST_STR_COMPONENT "[%ld/%ld]: " fmt " (in %s() at " __FILE__ ":" UST_XSTR(__LINE__) ")\n",    \
  88                 (long) getpid(),                \
  89                 (long) syscall(SYS_gettid),     \
  90                 ## args, __func__);             \
  91                 fflush(stderr);                 \
  92         } while(0)
  93
  94 #ifdef LTTNG_UST_DEBUG
  95 # define DBG(fmt, args...)                      ERRMSG(fmt, ## args)
  96 # define DBG_raw(fmt, args...)                                  \
  97         do {                                                    \
  98                 sigsafe_print_err(fmt, ## args);                \
  99                 fflush(stderr);                                 \
 100         } while(0)
 101 #else
 102 # define DBG(fmt, args...)                                      \
 103         do {                                                    \
 104                 if (ust_debug())                                \
 105                         ERRMSG(fmt, ## args);                   \
 106         } while (0)
 107 # define DBG_raw(fmt, args...)                                  \
 108         do {                                                    \
 109                 if (ust_debug()) {                              \
 110                         sigsafe_print_err(fmt, ## args);        \
 111                         fflush(stderr);                         \
 112                 }                                               \
 113         } while(0)
 114 #endif
 115 #define WARN(fmt, args...) ERRMSG("Warning: " fmt, ## args)
 116 #define ERR(fmt, args...) ERRMSG("Error: " fmt, ## args)
 117 #define BUG(fmt, args...) ERRMSG("BUG: " fmt, ## args)
 118
 119 #if (_POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600) && !defined(_GNU_SOURCE)
 120 #define PERROR(call, args...)\
 121         do { \
 122                 char buf[200] = "Error in strerror_r()"; \
 123                 strerror_r(errno, buf, sizeof(buf)); \
 124                 ERRMSG("Error: " call ": %s", ## args, buf); \
 125         } while(0);
 126 #else
 127 #define PERROR(call, args...)\
 128         do { \
 129                 char *buf; \
 130                 char tmp[200]; \
 131                 buf = strerror_r(errno, tmp, sizeof(tmp)); \
 132                 ERRMSG("Error: " call ": %s", ## args, buf); \
 133         } while(0);
 134 #endif
 135
 136 #define BUG_ON(condition)                                       \
 137         do {                                                    \
 138                 if (caa_unlikely(condition))                    \
 139                         ERR("condition not respected (BUG) on line %s:%d", __FILE__, __LINE__); \
 140         } while(0)
 141 #define WARN_ON(condition)                                      \
 142         do {                                                    \
 143                 if (caa_unlikely(condition))                    \
 144                         WARN("condition not respected on line %s:%d", __FILE__, __LINE__); \
 145         } while(0)
 146 #define WARN_ON_ONCE(condition) WARN_ON(condition)
 147
 148 #endif /* _USTERR_SIGNAL_SAFE_H */