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 <sys/syscall.h>
  26 #include <errno.h>
  27 #include <stdarg.h>
  28 #include <stdio.h>
  29 #include <share.h>
  30 #include "lttng/ust-tid.h"
  31
  32 enum ust_loglevel {
  33         UST_LOGLEVEL_UNKNOWN = 0,
  34         UST_LOGLEVEL_NORMAL,
  35         UST_LOGLEVEL_DEBUG,
  36 };
  37
  38 extern volatile enum ust_loglevel ust_loglevel;
  39 void init_usterr(void);
  40
  41 static inline int ust_debug(void)
  42 {
  43         return ust_loglevel == UST_LOGLEVEL_DEBUG;
  44 }
  45
  46 #ifndef UST_COMPONENT
  47 //#error UST_COMPONENT is undefined
  48 #define UST_COMPONENT libust
  49 #endif
  50
  51 /* To stringify the expansion of a define */
  52 #define UST_XSTR(d) UST_STR(d)
  53 #define UST_STR(s) #s
  54
  55 #define USTERR_MAX_LEN  512
  56
  57 /* We sometimes print in the tracing path, and tracing can occur in
  58  * signal handlers, so we must use a print method which is signal safe.
  59  */
  60
  61 extern int ust_safe_snprintf(char *str, size_t n, const char *fmt, ...)
  62         __attribute__ ((format (printf, 3, 4)));
  63
  64 static inline void __attribute__ ((format (printf, 1, 2)))
  65         __check_ust_safe_fmt(const char *fmt, ...)
  66 {
  67 }
  68
  69 /* Can't use dynamic allocation. Limit ourselves to USTERR_MAX_LEN chars. */
  70 /* Add end of string in case of buffer overflow. */
  71 #define sigsafe_print_err(fmt, args...)                                 \
  72 do {                                                                    \
  73         char ____buf[USTERR_MAX_LEN];                                   \
  74         int ____saved_errno;                                            \
  75         ____saved_errno = errno;        /* signal-safety */             \
  76         ust_safe_snprintf(____buf, sizeof(____buf), fmt, ## args);      \
  77         ____buf[sizeof(____buf) - 1] = 0;                               \
  78         patient_write(STDERR_FILENO, ____buf, strlen(____buf));         \
  79         errno = ____saved_errno;        /* signal-safety */             \
  80 } while (0)
  81
  82 #define UST_STR_COMPONENT UST_XSTR(UST_COMPONENT)
  83
  84 #define ERRMSG(fmt, args...)                    \
  85         do {                                    \
  86                 sigsafe_print_err(UST_STR_COMPONENT "[%ld/%ld]: " fmt " (in %s() at " __FILE__ ":" UST_XSTR(__LINE__) ")\n",    \
  87                 (long) getpid(),                \
  88                 (long) gettid(),                \
  89                 ## args, __func__);             \
  90                 fflush(stderr);                 \
  91         } while(0)
  92
  93 #ifdef LTTNG_UST_DEBUG
  94 # define DBG(fmt, args...)                      ERRMSG(fmt, ## args)
  95 # define DBG_raw(fmt, args...)                                  \
  96         do {                                                    \
  97                 sigsafe_print_err(fmt, ## args);                \
  98                 fflush(stderr);                                 \
  99         } while(0)
 100 #else
 101 # define DBG(fmt, args...)                                      \
 102         do {                                                    \
 103                 if (ust_debug())                                \
 104                         ERRMSG(fmt, ## args);                   \
 105         } while (0)
 106 # define DBG_raw(fmt, args...)                                  \
 107         do {                                                    \
 108                 if (ust_debug()) {                              \
 109                         sigsafe_print_err(fmt, ## args);        \
 110                         fflush(stderr);                         \
 111                 }                                               \
 112         } while(0)
 113 #endif
 114 #define WARN(fmt, args...) ERRMSG("Warning: " fmt, ## args)
 115 #define ERR(fmt, args...) ERRMSG("Error: " fmt, ## args)
 116 #define BUG(fmt, args...) ERRMSG("BUG: " fmt, ## args)
 117
 118 #if !defined(__linux__) || ((_POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600) && !defined(_GNU_SOURCE))
 119 /*
 120  * Version using XSI strerror_r.
 121  */
 122 #define PERROR(call, args...)\
 123         do { \
 124                 char buf[200] = "Error in strerror_r()"; \
 125                 strerror_r(errno, buf, sizeof(buf)); \
 126                 ERRMSG("Error: " call ": %s", ## args, buf); \
 127         } while(0);
 128 #else
 129 /*
 130  * Version using GNU strerror_r, for linux with appropriate defines.
 131  */
 132 #define PERROR(call, args...)\
 133         do { \
 134                 char *buf; \
 135                 char tmp[200]; \
 136                 buf = strerror_r(errno, tmp, sizeof(tmp)); \
 137                 ERRMSG("Error: " call ": %s", ## args, buf); \
 138         } while(0);
 139 #endif
 140
 141 #define BUG_ON(condition)                                       \
 142         do {                                                    \
 143                 if (caa_unlikely(condition))                    \
 144                         ERR("condition not respected (BUG) on line %s:%d", __FILE__, __LINE__); \
 145         } while(0)
 146 #define WARN_ON(condition)                                      \
 147         do {                                                    \
 148                 if (caa_unlikely(condition))                    \
 149                         WARN("condition not respected on line %s:%d", __FILE__, __LINE__); \
 150         } while(0)
 151 #define WARN_ON_ONCE(condition) WARN_ON(condition)
 152
 153 #endif /* _USTERR_SIGNAL_SAFE_H */