lib/vlog.h

   1 /*
   2  * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013 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 /* Logging.
  21  *
  22  *
  23  * Thread-safety
  24  * =============
  25  *
  26  * Fully thread safe.
  27  */
  28
  29 #include <limits.h>
  30 #include <stdarg.h>
  31 #include <stdbool.h>
  32 #include <time.h>
  33 #include "compiler.h"
  34 #include "ovs-thread.h"
  35 #include "sat-math.h"
  36 #include "token-bucket.h"
  37 #include "util.h"
  38 #include "list.h"
  39
  40 #ifdef  __cplusplus
  41 extern "C" {
  42 #endif
  43
  44 /* Logging severity levels.
  45  *
  46  * ovs-appctl(8) defines each of the log levels. */
  47 #define VLOG_LEVELS                             \
  48     VLOG_LEVEL(OFF,  LOG_ALERT,   1)            \
  49     VLOG_LEVEL(EMER, LOG_ALERT,   1)            \
  50     VLOG_LEVEL(ERR,  LOG_ERR,     3)            \
  51     VLOG_LEVEL(WARN, LOG_WARNING, 4)            \
  52     VLOG_LEVEL(INFO, LOG_NOTICE,  5)            \
  53     VLOG_LEVEL(DBG,  LOG_DEBUG,   7)
  54 enum vlog_level {
  55 #define VLOG_LEVEL(NAME, SYSLOG_LEVEL, RFC5424_LEVEL) VLL_##NAME,
  56     VLOG_LEVELS
  57 #undef VLOG_LEVEL
  58     VLL_N_LEVELS
  59 };
  60
  61 const char *vlog_get_level_name(enum vlog_level);
  62 enum vlog_level vlog_get_level_val(const char *name);
  63
  64 /* Facilities that we can log to. */
  65 #define VLOG_FACILITIES                                                 \
  66     VLOG_FACILITY(SYSLOG, "ovs|%05N|%c%T|%p|%m")                        \
  67     VLOG_FACILITY(CONSOLE, "%D{%Y-%m-%dT%H:%M:%SZ}|%05N|%c%T|%p|%m")    \
  68     VLOG_FACILITY(FILE, "%D{%Y-%m-%dT%H:%M:%S.###Z}|%05N|%c%T|%p|%m")
  69 enum vlog_facility {
  70 #define VLOG_FACILITY(NAME, PATTERN) VLF_##NAME,
  71     VLOG_FACILITIES
  72 #undef VLOG_FACILITY
  73     VLF_N_FACILITIES,
  74     VLF_ANY_FACILITY = -1
  75 };
  76
  77 const char *vlog_get_facility_name(enum vlog_facility);
  78 enum vlog_facility vlog_get_facility_val(const char *name);
  79
  80 /* A log module. */
  81 struct vlog_module {
  82     struct list list;
  83     const char *name;             /* User-visible name. */
  84     int levels[VLF_N_FACILITIES]; /* Minimum log level for each facility. */
  85     int min_level;                /* Minimum log level for any facility. */
  86     bool honor_rate_limits;       /* Set false to ignore rate limits. */
  87 };
  88
  89 /* Global list of all logging modules */
  90 extern struct list vlog_modules;
  91
  92 /* Creates and initializes a global instance of a module named MODULE. */
  93 #define VLOG_DEFINE_MODULE(MODULE)                                      \
  94         VLOG_DEFINE_MODULE__(MODULE)                                    \
  95         OVS_CONSTRUCTOR(init_##MODULE) {                                \
  96                 list_insert(&vlog_modules, &VLM_##MODULE.list);         \
  97         }                                                               \
  98
  99 const char *vlog_get_module_name(const struct vlog_module *);
 100 struct vlog_module *vlog_module_from_name(const char *name);
 101
 102 /* Rate-limiter for log messages. */
 103 struct vlog_rate_limit {
 104     struct token_bucket token_bucket;
 105     time_t first_dropped;       /* Time first message was dropped. */
 106     time_t last_dropped;        /* Time of most recent message drop. */
 107     unsigned int n_dropped;     /* Number of messages dropped. */
 108     struct ovs_mutex mutex;     /* Mutual exclusion for rate limit. */
 109 };
 110
 111 /* Number of tokens to emit a message.  We add 'rate' tokens per millisecond,
 112  * thus 60,000 tokens are required to emit one message per minute. */
 113 #define VLOG_MSG_TOKENS (60 * 1000)
 114
 115 /* Initializer for a struct vlog_rate_limit, to set up a maximum rate of RATE
 116  * messages per minute and a maximum burst size of BURST messages. */
 117 #define VLOG_RATE_LIMIT_INIT(RATE, BURST)                               \
 118         {                                                               \
 119             TOKEN_BUCKET_INIT(RATE, SAT_MUL(BURST, VLOG_MSG_TOKENS)),   \
 120             0,                              /* first_dropped */         \
 121             0,                              /* last_dropped */          \
 122             0,                              /* n_dropped */             \
 123             OVS_MUTEX_INITIALIZER           /* mutex */                 \
 124         }
 125
 126 /* Configuring how each module logs messages. */
 127 enum vlog_level vlog_get_level(const struct vlog_module *, enum vlog_facility);
 128 void vlog_set_levels(struct vlog_module *,
 129                      enum vlog_facility, enum vlog_level);
 130 char *vlog_set_levels_from_string(const char *) WARN_UNUSED_RESULT;
 131 void vlog_set_levels_from_string_assert(const char *);
 132 char *vlog_get_levels(void);
 133 bool vlog_is_enabled(const struct vlog_module *, enum vlog_level);
 134 bool vlog_should_drop(const struct vlog_module *, enum vlog_level,
 135                       struct vlog_rate_limit *);
 136 void vlog_set_verbosity(const char *arg);
 137
 138 /* Configuring log facilities. */
 139 void vlog_set_pattern(enum vlog_facility, const char *pattern);
 140 int vlog_set_log_file(const char *file_name);
 141 int vlog_reopen_log_file(void);
 142
 143 /* Configure syslog target. */
 144 void vlog_set_syslog_target(const char *target);
 145
 146 /* Initialization. */
 147 void vlog_init(void);
 148 void vlog_enable_async(void);
 149
 150 /* Functions for actual logging. */
 151 void vlog(const struct vlog_module *, enum vlog_level, const char *format, ...)
 152     PRINTF_FORMAT (3, 4);
 153 void vlog_valist(const struct vlog_module *, enum vlog_level,
 154                  const char *, va_list)
 155     PRINTF_FORMAT (3, 0);
 156
 157 void vlog_fatal(const struct vlog_module *, const char *format, ...)
 158     PRINTF_FORMAT (2, 3) NO_RETURN;
 159 void vlog_fatal_valist(const struct vlog_module *, const char *format, va_list)
 160     PRINTF_FORMAT (2, 0) NO_RETURN;
 161
 162 void vlog_abort(const struct vlog_module *, const char *format, ...)
 163     PRINTF_FORMAT (2, 3) NO_RETURN;
 164 void vlog_abort_valist(const struct vlog_module *, const char *format, va_list)
 165     PRINTF_FORMAT (2, 0) NO_RETURN;
 166
 167 void vlog_rate_limit(const struct vlog_module *, enum vlog_level,
 168                      struct vlog_rate_limit *, const char *, ...)
 169     PRINTF_FORMAT (4, 5);
 170
 171 /* Creates and initializes a global instance of a module named MODULE, and
 172  * defines a static variable named THIS_MODULE that points to it, for use with
 173  * the convenience macros below. */
 174 #define VLOG_DEFINE_THIS_MODULE(MODULE)                                 \
 175         VLOG_DEFINE_MODULE(MODULE);                                     \
 176         static struct vlog_module *const THIS_MODULE = &VLM_##MODULE
 177
 178 /* Convenience macros.  These assume that THIS_MODULE points to a "struct
 179  * vlog_module" for the current module, as set up by e.g. the
 180  * VLOG_DEFINE_MODULE macro above.
 181  *
 182  * Guaranteed to preserve errno.
 183  */
 184 #define VLOG_FATAL(...) vlog_fatal(THIS_MODULE, __VA_ARGS__)
 185 #define VLOG_ABORT(...) vlog_abort(THIS_MODULE, __VA_ARGS__)
 186 #define VLOG_EMER(...) VLOG(VLL_EMER, __VA_ARGS__)
 187 #define VLOG_ERR(...) VLOG(VLL_ERR, __VA_ARGS__)
 188 #define VLOG_WARN(...) VLOG(VLL_WARN, __VA_ARGS__)
 189 #define VLOG_INFO(...) VLOG(VLL_INFO, __VA_ARGS__)
 190 #define VLOG_DBG(...) VLOG(VLL_DBG, __VA_ARGS__)
 191
 192 /* More convenience macros, for testing whether a given level is enabled in
 193  * THIS_MODULE.  When constructing a log message is expensive, this enables it
 194  * to be skipped. */
 195 #define VLOG_IS_ERR_ENABLED() vlog_is_enabled(THIS_MODULE, VLL_ERR)
 196 #define VLOG_IS_WARN_ENABLED() vlog_is_enabled(THIS_MODULE, VLL_WARN)
 197 #define VLOG_IS_INFO_ENABLED() vlog_is_enabled(THIS_MODULE, VLL_INFO)
 198 #define VLOG_IS_DBG_ENABLED() vlog_is_enabled(THIS_MODULE, VLL_DBG)
 199
 200 /* Convenience macros for rate-limiting.
 201  * Guaranteed to preserve errno.
 202  */
 203 #define VLOG_ERR_RL(RL, ...) VLOG_RL(RL, VLL_ERR, __VA_ARGS__)
 204 #define VLOG_WARN_RL(RL, ...) VLOG_RL(RL, VLL_WARN, __VA_ARGS__)
 205 #define VLOG_INFO_RL(RL, ...) VLOG_RL(RL, VLL_INFO, __VA_ARGS__)
 206 #define VLOG_DBG_RL(RL, ...) VLOG_RL(RL, VLL_DBG, __VA_ARGS__)
 207
 208 /* Convenience macros to additionally store log message in buffer
 209  * Caller is responsible for freeing *ERRP afterwards */
 210 #define VLOG_ERR_BUF(ERRP, ...) VLOG_ERRP(ERRP, VLL_ERR, __VA_ARGS__)
 211 #define VLOG_WARN_BUF(ERRP, ...) VLOG_ERRP(ERRP, VLL_WARN, __VA_ARGS__)
 212
 213 #define VLOG_DROP_ERR(RL) vlog_should_drop(THIS_MODULE, VLL_ERR, RL)
 214 #define VLOG_DROP_WARN(RL) vlog_should_drop(THIS_MODULE, VLL_WARN, RL)
 215 #define VLOG_DROP_INFO(RL) vlog_should_drop(THIS_MODULE, VLL_INFO, RL)
 216 #define VLOG_DROP_DBG(RL) vlog_should_drop(THIS_MODULE, VLL_DBG, RL)
 217
 218 /* Macros for logging at most once per execution. */
 219 #define VLOG_ERR_ONCE(...) VLOG_ONCE(VLL_ERR, __VA_ARGS__)
 220 #define VLOG_WARN_ONCE(...) VLOG_ONCE(VLL_WARN, __VA_ARGS__)
 221 #define VLOG_INFO_ONCE(...) VLOG_ONCE(VLL_INFO, __VA_ARGS__)
 222 #define VLOG_DBG_ONCE(...) VLOG_ONCE(VLL_DBG, __VA_ARGS__)
 223
 224 /* Command line processing. */
 225 #define VLOG_OPTION_ENUMS                       \
 226         OPT_LOG_FILE,                           \
 227         OPT_SYSLOG_TARGET
 228
 229 #define VLOG_LONG_OPTIONS                                               \
 230         {"verbose",       optional_argument, NULL, 'v'},                \
 231         {"log-file",      optional_argument, NULL, OPT_LOG_FILE},       \
 232         {"syslog-target", optional_argument, NULL, OPT_SYSLOG_TARGET}
 233
 234 #define VLOG_OPTION_HANDLERS                    \
 235         case 'v':                               \
 236             vlog_set_verbosity(optarg);         \
 237             break;                              \
 238         case OPT_LOG_FILE:                      \
 239             vlog_set_log_file(optarg);          \
 240             break;                              \
 241         case OPT_SYSLOG_TARGET:                 \
 242             vlog_set_syslog_target(optarg);     \
 243             break;
 244
 245 void vlog_usage(void);
 246
 247 /* Implementation details. */
 248 #define VLOG(LEVEL, ...)                                \
 249     do {                                                \
 250         enum vlog_level level__ = LEVEL;                \
 251         if (THIS_MODULE->min_level >= level__) {        \
 252             vlog(THIS_MODULE, level__, __VA_ARGS__);    \
 253         }                                               \
 254     } while (0)
 255 #define VLOG_RL(RL, LEVEL, ...)                                     \
 256     do {                                                            \
 257         enum vlog_level level__ = LEVEL;                            \
 258         if (THIS_MODULE->min_level >= level__) {                    \
 259             vlog_rate_limit(THIS_MODULE, level__, RL, __VA_ARGS__); \
 260         }                                                           \
 261     } while (0)
 262 #define VLOG_ONCE(LEVEL, ...)                                           \
 263     do {                                                                \
 264         static struct ovsthread_once once = OVSTHREAD_ONCE_INITIALIZER; \
 265         if (ovsthread_once_start(&once)) {                              \
 266             vlog(THIS_MODULE, LEVEL, __VA_ARGS__);                      \
 267             ovsthread_once_done(&once);                                 \
 268         }                                                               \
 269     } while (0)
 270 #define VLOG_ERRP(ERRP, LEVEL, ...)                                     \
 271     do {                                                                \
 272         VLOG(LEVEL, __VA_ARGS__);                                       \
 273         if (ERRP) {                                                     \
 274             *(ERRP) = xasprintf(__VA_ARGS__);                           \
 275         }                                                               \
 276     } while (0)
 277
 278 #define VLOG_DEFINE_MODULE__(MODULE)                                    \
 279         extern struct vlog_module VLM_##MODULE;                         \
 280         struct vlog_module VLM_##MODULE =                               \
 281         {                                                               \
 282             LIST_INITIALIZER(&VLM_##MODULE.list),                       \
 283             #MODULE,                                        /* name */  \
 284             { VLL_INFO, VLL_INFO, VLL_INFO },             /* levels */  \
 285             VLL_INFO,                                  /* min_level */  \
 286             true                               /* honor_rate_limits */  \
 287         };
 288
 289 #ifdef  __cplusplus
 290 }
 291 #endif
 292
 293
 294 #endif /* vlog.h */