include/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 <errno.h>
  26 #include <stdarg.h>
  27 #include <stdio.h>
  28 #include <share.h>
  29 #include "lttng/ust-tid.h"
  30
  31 enum ust_loglevel {
  32         UST_LOGLEVEL_UNKNOWN = 0,
  33         UST_LOGLEVEL_NORMAL,
  34         UST_LOGLEVEL_DEBUG,
  35 };
  36
  37 extern volatile enum ust_loglevel ust_loglevel;
  38 void init_usterr(void);
  39
  40 #ifdef LTTNG_UST_DEBUG
  41 static inline int ust_debug(void)
  42 {
  43         return 1;
  44 }
  45 #else /* #ifdef LTTNG_UST_DEBUG */
  46 static inline int ust_debug(void)
  47 {
  48         return ust_loglevel == UST_LOGLEVEL_DEBUG;
  49 }
  50 #endif /* #else #ifdef LTTNG_UST_DEBUG */
  51
  52 #ifndef UST_COMPONENT
  53 //#error UST_COMPONENT is undefined
  54 #define UST_COMPONENT libust
  55 #endif
  56
  57 /* To stringify the expansion of a define */
  58 #define UST_XSTR(d) UST_STR(d)
  59 #define UST_STR(s) #s
  60
  61 #define USTERR_MAX_LEN  512
  62
  63 /* We sometimes print in the tracing path, and tracing can occur in
  64  * signal handlers, so we must use a print method which is signal safe.
  65  */
  66
  67 extern int ust_safe_snprintf(char *str, size_t n, const char *fmt, ...)
  68         __attribute__ ((format (printf, 3, 4)));
  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         if (ust_debug()) {                                              \
  75                 char ____buf[USTERR_MAX_LEN];                           \
  76                 int ____saved_errno;                                    \
  77                                                                         \
  78                 ____saved_errno = errno;        /* signal-safety */     \
  79                 ust_safe_snprintf(____buf, sizeof(____buf), fmt, ## args); \
  80                 ____buf[sizeof(____buf) - 1] = 0;                       \
  81                 patient_write(STDERR_FILENO, ____buf, strlen(____buf)); \
  82                 errno = ____saved_errno;        /* signal-safety */     \
  83                 fflush(stderr);                                         \
  84         }                                                               \
  85 } while (0)
  86
  87 #define UST_STR_COMPONENT UST_XSTR(UST_COMPONENT)
  88
  89 #define ERRMSG(fmt, args...)                    \
  90         do {                                    \
  91                 sigsafe_print_err(UST_STR_COMPONENT "[%ld/%ld]: " fmt " (in %s() at " __FILE__ ":" UST_XSTR(__LINE__) ")\n", \
  92                 (long) getpid(),                \
  93                 (long) lttng_gettid(),          \
  94                 ## args, __func__);             \
  95         } while(0)
  96
  97
  98 #define DBG(fmt, args...)       ERRMSG(fmt, ## args)
  99 #define DBG_raw(fmt, args...)   sigsafe_print_err(fmt, ## args)
 100 #define WARN(fmt, args...)      ERRMSG("Warning: " fmt, ## args)
 101 #define ERR(fmt, args...)       ERRMSG("Error: " fmt, ## args)
 102 #define BUG(fmt, args...)       ERRMSG("BUG: " fmt, ## args)
 103
 104 #if !defined(__GLIBC__) || ((_POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600) && !defined(_GNU_SOURCE))
 105 /*
 106  * Version using XSI strerror_r.
 107  */
 108 #define PERROR(call, args...)                                           \
 109         do {                                                            \
 110                 if (ust_debug()) {                                      \
 111                         char buf[200] = "Error in strerror_r()";        \
 112                         strerror_r(errno, buf, sizeof(buf));            \
 113                         ERRMSG("Error: " call ": %s", ## args, buf);    \
 114                 }                                                       \
 115         } while(0)
 116 #else
 117 /*
 118  * Version using GNU strerror_r, for linux with appropriate defines.
 119  */
 120 #define PERROR(call, args...)                                           \
 121         do {                                                            \
 122                 if (ust_debug()) {                                      \
 123                         char *buf;                                      \
 124                         char tmp[200];                                  \
 125                         buf = strerror_r(errno, tmp, sizeof(tmp));      \
 126                         ERRMSG("Error: " call ": %s", ## args, buf);    \
 127                 }                                                       \
 128         } while(0)
 129 #endif
 130
 131 #define BUG_ON(condition)                                       \
 132         do {                                                    \
 133                 if (caa_unlikely(condition))                    \
 134                         ERR("condition not respected (BUG) on line %s:%d", __FILE__, __LINE__); \
 135         } while(0)
 136 #define WARN_ON(condition)                                      \
 137         do {                                                    \
 138                 if (caa_unlikely(condition))                    \
 139                         WARN("condition not respected on line %s:%d", __FILE__, __LINE__); \
 140         } while(0)
 141 #define WARN_ON_ONCE(condition) WARN_ON(condition)
 142
 143 #endif /* _USTERR_SIGNAL_SAFE_H */