lib/vlog.h

   1 /*
   2  * Copyright (c) 2008, 2009, 2010, 2011, 2012 Nicira, Inc.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at:
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 #ifndef VLOG_H
  18 #define VLOG_H 1
  19
  20 #include <limits.h>
  21 #include <stdarg.h>
  22 #include <stdbool.h>
  23 #include <time.h>
  24 #include "compiler.h"
  25 #include "sat-math.h"
  26 #include "token-bucket.h"
  27 #include "util.h"
  28
  29 #ifdef  __cplusplus
  30 extern "C" {
  31 #endif
  32
  33 /* Logging severity levels.
  34  *
  35  * ovs-appctl(8) defines each of the log levels. */
  36 #define VLOG_LEVELS                             \
  37     VLOG_LEVEL(OFF, LOG_ALERT)                  \
  38     VLOG_LEVEL(EMER, LOG_ALERT)                 \
  39     VLOG_LEVEL(ERR, LOG_ERR)                    \
  40     VLOG_LEVEL(WARN, LOG_WARNING)               \
  41     VLOG_LEVEL(INFO, LOG_NOTICE)                \
  42     VLOG_LEVEL(DBG, LOG_DEBUG)
  43 enum vlog_level {
  44 #define VLOG_LEVEL(NAME, SYSLOG_LEVEL) VLL_##NAME,
  45     VLOG_LEVELS
  46 #undef VLOG_LEVEL
  47     VLL_N_LEVELS
  48 };
  49
  50 const char *vlog_get_level_name(enum vlog_level);
  51 enum vlog_level vlog_get_level_val(const char *name);
  52
  53 /* Facilities that we can log to. */
  54 #define VLOG_FACILITIES                                         \
  55     VLOG_FACILITY(SYSLOG, "%05N|%c|%p|%m")                      \
  56     VLOG_FACILITY(CONSOLE, "%D{%Y-%m-%dT%H:%M:%SZ}|%05N|%c|%p|%m")  \
  57     VLOG_FACILITY(FILE, "%D{%Y-%m-%dT%H:%M:%SZ}|%05N|%c|%p|%m")
  58 enum vlog_facility {
  59 #define VLOG_FACILITY(NAME, PATTERN) VLF_##NAME,
  60     VLOG_FACILITIES
  61 #undef VLOG_FACILITY
  62     VLF_N_FACILITIES,
  63     VLF_ANY_FACILITY = -1
  64 };
  65
  66 const char *vlog_get_facility_name(enum vlog_facility);
  67 enum vlog_facility vlog_get_facility_val(const char *name);
  68
  69 /* A log module. */
  70 struct vlog_module {
  71     const char *name;             /* User-visible name. */
  72     int levels[VLF_N_FACILITIES]; /* Minimum log level for each facility. */
  73     int min_level;                /* Minimum log level for any facility. */
  74 };
  75
  76 /* Creates and initializes a global instance of a module named MODULE. */
  77 #if USE_LINKER_SECTIONS
  78 #define VLOG_DEFINE_MODULE(MODULE)                                      \
  79         VLOG_DEFINE_MODULE__(MODULE)                                    \
  80         extern struct vlog_module *vlog_module_ptr_##MODULE;            \
  81         struct vlog_module *vlog_module_ptr_##MODULE                    \
  82             __attribute__((section("vlog_modules"))) = &VLM_##MODULE
  83 #else
  84 #define VLOG_DEFINE_MODULE(MODULE) extern struct vlog_module VLM_##MODULE
  85 #endif
  86
  87 const char *vlog_get_module_name(const struct vlog_module *);
  88 struct vlog_module *vlog_module_from_name(const char *name);
  89
  90 /* Rate-limiter for log messages. */
  91 struct vlog_rate_limit {
  92     struct token_bucket token_bucket;
  93     time_t first_dropped;       /* Time first message was dropped. */
  94     time_t last_dropped;        /* Time of most recent message drop. */
  95     unsigned int n_dropped;     /* Number of messages dropped. */
  96 };
  97
  98 /* Number of tokens to emit a message.  We add 'rate' tokens per millisecond,
  99  * thus 60,000 tokens are required to emit one message per minute. */
 100 #define VLOG_MSG_TOKENS (60 * 1000)
 101
 102 /* Initializer for a struct vlog_rate_limit, to set up a maximum rate of RATE
 103  * messages per minute and a maximum burst size of BURST messages. */
 104 #define VLOG_RATE_LIMIT_INIT(RATE, BURST)                               \
 105         {                                                               \
 106             TOKEN_BUCKET_INIT(RATE, SAT_MUL(BURST, VLOG_MSG_TOKENS)),   \
 107             0,                              /* first_dropped */         \
 108             0,                              /* last_dropped */          \
 109             0,                              /* n_dropped */             \
 110         }
 111
 112 /* Configuring how each module logs messages. */
 113 enum vlog_level vlog_get_level(const struct vlog_module *, enum vlog_facility);
 114 void vlog_set_levels(struct vlog_module *,
 115                      enum vlog_facility, enum vlog_level);
 116 char *vlog_set_levels_from_string(const char *);
 117 char *vlog_get_levels(void);
 118 bool vlog_is_enabled(const struct vlog_module *, enum vlog_level);
 119 bool vlog_should_drop(const struct vlog_module *, enum vlog_level,
 120                       struct vlog_rate_limit *);
 121 void vlog_set_verbosity(const char *arg);
 122
 123 /* Configuring log facilities. */
 124 void vlog_set_pattern(enum vlog_facility, const char *pattern);
 125 const char *vlog_get_log_file(void);
 126 int vlog_set_log_file(const char *file_name);
 127 int vlog_reopen_log_file(void);
 128
 129 /* Initialization. */
 130 void vlog_init(void);
 131 void vlog_exit(void);
 132
 133 /* Functions for actual logging. */
 134 void vlog(const struct vlog_module *, enum vlog_level, const char *format, ...)
 135     PRINTF_FORMAT (3, 4);
 136 void vlog_valist(const struct vlog_module *, enum vlog_level,
 137                  const char *, va_list)
 138     PRINTF_FORMAT (3, 0);
 139
 140 void vlog_fatal(const struct vlog_module *, const char *format, ...)
 141     PRINTF_FORMAT (2, 3) NO_RETURN;
 142 void vlog_fatal_valist(const struct vlog_module *, const char *format, va_list)
 143     PRINTF_FORMAT (2, 0) NO_RETURN;
 144
 145 void vlog_rate_limit(const struct vlog_module *, enum vlog_level,
 146                      struct vlog_rate_limit *, const char *, ...)
 147     PRINTF_FORMAT (4, 5);
 148
 149 /* Creates and initializes a global instance of a module named MODULE, and
 150  * defines a static variable named THIS_MODULE that points to it, for use with
 151  * the convenience macros below. */
 152 #define VLOG_DEFINE_THIS_MODULE(MODULE)                                 \
 153         VLOG_DEFINE_MODULE(MODULE);                                     \
 154         static struct vlog_module *const THIS_MODULE = &VLM_##MODULE
 155
 156 /* Convenience macros.  These assume that THIS_MODULE points to a "struct
 157  * vlog_module" for the current module, as set up by e.g. the
 158  * VLOG_DEFINE_MODULE macro above.
 159  *
 160  * Guaranteed to preserve errno.
 161  */
 162 #define VLOG_FATAL(...) vlog_fatal(THIS_MODULE, __VA_ARGS__)
 163 #define VLOG_EMER(...) VLOG(VLL_EMER, __VA_ARGS__)
 164 #define VLOG_ERR(...) VLOG(VLL_ERR, __VA_ARGS__)
 165 #define VLOG_WARN(...) VLOG(VLL_WARN, __VA_ARGS__)
 166 #define VLOG_INFO(...) VLOG(VLL_INFO, __VA_ARGS__)
 167 #define VLOG_DBG(...) VLOG(VLL_DBG, __VA_ARGS__)
 168
 169 /* More convenience macros, for testing whether a given level is enabled in
 170  * THIS_MODULE.  When constructing a log message is expensive, this enables it
 171  * to be skipped. */
 172 #define VLOG_IS_ERR_ENABLED() vlog_is_enabled(THIS_MODULE, VLL_ERR)
 173 #define VLOG_IS_WARN_ENABLED() vlog_is_enabled(THIS_MODULE, VLL_WARN)
 174 #define VLOG_IS_INFO_ENABLED() vlog_is_enabled(THIS_MODULE, VLL_INFO)
 175 #define VLOG_IS_DBG_ENABLED() vlog_is_enabled(THIS_MODULE, VLL_DBG)
 176
 177 /* Convenience macros for rate-limiting.
 178  * Guaranteed to preserve errno.
 179  */
 180 #define VLOG_ERR_RL(RL, ...) VLOG_RL(RL, VLL_ERR, __VA_ARGS__)
 181 #define VLOG_WARN_RL(RL, ...) VLOG_RL(RL, VLL_WARN, __VA_ARGS__)
 182 #define VLOG_INFO_RL(RL, ...) VLOG_RL(RL, VLL_INFO, __VA_ARGS__)
 183 #define VLOG_DBG_RL(RL, ...) VLOG_RL(RL, VLL_DBG, __VA_ARGS__)
 184
 185 #define VLOG_DROP_ERR(RL) vlog_should_drop(THIS_MODULE, VLL_ERR, RL)
 186 #define VLOG_DROP_WARN(RL) vlog_should_drop(THIS_MODULE, VLL_WARN, RL)
 187 #define VLOG_DROP_INFO(RL) vlog_should_drop(THIS_MODULE, VLL_INFO, RL)
 188 #define VLOG_DROP_DBG(RL) vlog_should_drop(THIS_MODULE, VLL_DBG, RL)
 189
 190 /* Macros for logging at most once per execution. */
 191 #define VLOG_ERR_ONCE(...) VLOG_ONCE(VLL_ERR, __VA_ARGS__)
 192 #define VLOG_WARN_ONCE(...) VLOG_ONCE(VLL_WARN, __VA_ARGS__)
 193 #define VLOG_INFO_ONCE(...) VLOG_ONCE(VLL_INFO, __VA_ARGS__)
 194 #define VLOG_DBG_ONCE(...) VLOG_ONCE(VLL_DBG, __VA_ARGS__)
 195
 196 /* Command line processing. */
 197 #define VLOG_OPTION_ENUMS OPT_LOG_FILE
 198 #define VLOG_LONG_OPTIONS                                   \
 199         {"verbose",     optional_argument, NULL, 'v'},         \
 200         {"log-file",    optional_argument, NULL, OPT_LOG_FILE}
 201 #define VLOG_OPTION_HANDLERS                    \
 202         case 'v':                               \
 203             vlog_set_verbosity(optarg);         \
 204             break;                              \
 205         case OPT_LOG_FILE:                      \
 206             vlog_set_log_file(optarg);          \
 207             break;
 208 void vlog_usage(void);
 209
 210 /* Implementation details. */
 211 #define VLOG(LEVEL, ...)                                \
 212     do {                                                \
 213         enum vlog_level level__ = LEVEL;                \
 214         if (THIS_MODULE->min_level >= level__) {        \
 215             vlog(THIS_MODULE, level__, __VA_ARGS__);    \
 216         }                                               \
 217     } while (0)
 218 #define VLOG_RL(RL, LEVEL, ...)                                     \
 219     do {                                                            \
 220         enum vlog_level level__ = LEVEL;                            \
 221         if (THIS_MODULE->min_level >= level__) {                    \
 222             vlog_rate_limit(THIS_MODULE, level__, RL, __VA_ARGS__); \
 223         }                                                           \
 224     } while (0)
 225 #define VLOG_ONCE(LEVEL, ...)                       \
 226     do {                                            \
 227         static bool already_logged;                 \
 228         if (!already_logged) {                      \
 229             already_logged = true;                  \
 230             vlog(THIS_MODULE, LEVEL, __VA_ARGS__);  \
 231         }                                           \
 232     } while (0)
 233
 234 #define VLOG_DEFINE_MODULE__(MODULE)                                    \
 235         extern struct vlog_module VLM_##MODULE;                         \
 236         struct vlog_module VLM_##MODULE =                               \
 237         {                                                               \
 238             #MODULE,                                      /* name */    \
 239             { [ 0 ... VLF_N_FACILITIES - 1] = VLL_INFO }, /* levels */  \
 240             VLL_INFO,                                     /* min_level */ \
 241         };
 242
 243 #ifdef  __cplusplus
 244 }
 245 #endif
 246
 247
 248 #endif /* vlog.h */