lib/debug.h

   1 /*
   2  * Debugging utilities.
   3  * Copyright (C) 2018  Cumulus Networks, Inc.
   4  * Quentin Young
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License as published by the Free
   8  * Software Foundation; either version 2 of the License, or (at your option)
   9  * any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  14  * more details.
  15  *
  16  * You should have received a copy of the GNU General Public License along
  17  * with this program; see the file COPYING; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20 #ifndef _FRRDEBUG_H
  21 #define _FRRDEBUG_H
  22
  23 #include <zebra.h>
  24 #include "command.h"
  25 #include "frratomic.h"
  26
  27 #ifdef __cplusplus
  28 extern "C" {
  29 #endif
  30
  31 /*
  32  * Debugging modes.
  33  *
  34  * FRR's convention is that a debug statement issued under the vty CONFIG_NODE
  35  * persists to the config file, whereas the same debug statement issued from
  36  * the ENABLE_NODE only persists for the current session. These are mapped to
  37  * DEBUG_MODE_CONF and DEBUG_MODE_TERM respectively.
  38  *
  39  * They are not mutually exclusive and are placed in the MSB of the flags
  40  * field in a debugging record.
  41  */
  42 #define DEBUG_MODE_TERM 0x01000000
  43 #define DEBUG_MODE_CONF 0x02000000
  44 #define DEBUG_MODE_ALL (DEBUG_MODE_TERM | DEBUG_MODE_CONF)
  45 #define DEBUG_MODE_NONE 0x00000000
  46 #define DEBUG_OPT_ALL 0x00FFFFFF
  47 #define DEBUG_OPT_NONE 0x00000000
  48
  49
  50 /*
  51  * Debugging record.
  52  *
  53  * All operations on this record exposed in this header are MT-safe.
  54  *
  55  * flags
  56  *    A bitfield with the following format (bytes high to low)
  57  *    - [0] Debugging mode field (MSB)  | Mode
  58  *    - [1] Arbitrary flag field        | Option
  59  *    - [2] Arbitrary flag field        | Option
  60  *    - [3] Arbitrary flag field (LSB)  | Option
  61  *
  62  *              ALL THESE BYTES ARE YOURS - EXCEPT MODE.
  63  *                      ATTEMPT NO BIT OPS THERE.
  64  *
  65  *    The MSB of this field determines the debug mode, Use the DEBUG_MODE*
  66  *    macros to manipulate this byte.
  67  *
  68  *    The low 3 bytes of this field may be used to store arbitrary information.
  69  *    Usually they are used to store flags that tune how detailed the logging
  70  *    for a particular debug record is. Use the DEBUG_OPT* macros to manipulate
  71  *    those bytes.
  72  *
  73  *    All operations performed on this field should be done using the macros
  74  *    later in this header file. They are guaranteed to be atomic operations
  75  *    with respect to this field. Using anything except the macros to
  76  *    manipulate the flags field in a multithreaded environment results in
  77  *    undefined behavior.
  78  *
  79  * desc
  80  *    Human-readable description of this debugging record.
  81  */
  82 struct debug {
  83         atomic_uint_fast32_t flags;
  84         const char *desc;
  85 };
  86
  87 /*
  88  * Callback set for debugging code.
  89  *
  90  * debug_set_all
  91  *    Function pointer to call when the user requests that all debugs have a
  92  *    mode set.
  93  */
  94 struct debug_callbacks {
  95         /*
  96          * flags
  97          *    flags to set on debug flag fields
  98          *
  99          * set
 100          *    true: set flags
 101          *    false: unset flags
 102          */
 103         void (*debug_set_all)(uint32_t flags, bool set);
 104 };
 105
 106 /*
 107  * Check if a mode is set for a debug.
 108  *
 109  * MT-Safe
 110  */
 111 #define DEBUG_MODE_CHECK(name, mode)                                           \
 112         CHECK_FLAG_ATOMIC(&(name)->flags, (mode)&DEBUG_MODE_ALL)
 113
 114 /*
 115  * Check if an option bit is set for a debug.
 116  *
 117  * MT-Safe
 118  */
 119 #define DEBUG_OPT_CHECK(name, opt)                                             \
 120         CHECK_FLAG_ATOMIC(&(name)->flags, (opt)&DEBUG_OPT_ALL)
 121
 122 /*
 123  * Check if bits are set for a debug.
 124  *
 125  * MT-Safe
 126  */
 127 #define DEBUG_FLAGS_CHECK(name, fl) CHECK_FLAG_ATOMIC(&(name)->flags, (fl))
 128
 129 /*
 130  * Set modes on a debug.
 131  *
 132  * MT-Safe
 133  */
 134 #define DEBUG_MODE_SET(name, mode, onoff)                                      \
 135         do {                                                                   \
 136                 if (onoff)                                                     \
 137                         SET_FLAG_ATOMIC(&(name)->flags,                        \
 138                                         (mode)&DEBUG_MODE_ALL);                \
 139                 else                                                           \
 140                         UNSET_FLAG_ATOMIC(&(name)->flags,                      \
 141                                           (mode)&DEBUG_MODE_ALL);              \
 142         } while (0)
 143
 144 /* Convenience macros for specific set operations. */
 145 #define DEBUG_MODE_ON(name, mode) DEBUG_MODE_SET(name, mode, true)
 146 #define DEBUG_MODE_OFF(name, mode) DEBUG_MODE_SET(name, mode, false)
 147
 148 /*
 149  * Set options on a debug.
 150  *
 151  * MT-Safe
 152  */
 153 #define DEBUG_OPT_SET(name, opt, onoff)                                        \
 154         do {                                                                   \
 155                 if (onoff)                                                     \
 156                         SET_FLAG_ATOMIC(&(name)->flags, (opt)&DEBUG_OPT_ALL);  \
 157                 else                                                           \
 158                         UNSET_FLAG_ATOMIC(&(name)->flags,                      \
 159                                           (opt)&DEBUG_OPT_ALL);                \
 160         } while (0)
 161
 162 /* Convenience macros for specific set operations. */
 163 #define DEBUG_OPT_ON(name, opt) DEBUG_OPT_SET(name, opt, true)
 164 #define DEBUG_OPT_OFF(name, opt) DEBUG_OPT_SET(name, opt, true)
 165
 166 /*
 167  * Set bits on a debug.
 168  *
 169  * MT-Safe
 170  */
 171 #define DEBUG_FLAGS_SET(name, fl, onoff)                                       \
 172         do {                                                                   \
 173                 if (onoff)                                                     \
 174                         SET_FLAG_ATOMIC(&(name)->flags, (fl));                 \
 175                 else                                                           \
 176                         UNSET_FLAG_ATOMIC(&(name)->flags, (fl));               \
 177         } while (0)
 178
 179 /* Convenience macros for specific set operations. */
 180 #define DEBUG_FLAGS_ON(name, fl) DEBUG_FLAGS_SET(&(name)->flags, (type), true)
 181 #define DEBUG_FLAGS_OFF(name, fl) DEBUG_FLAGS_SET(&(name)->flags, (type), false)
 182
 183 /*
 184  * Unset all modes and options on a debug.
 185  *
 186  * MT-Safe
 187  */
 188 #define DEBUG_CLEAR(name) RESET_FLAG_ATOMIC(&(name)->flags)
 189
 190 /*
 191  * Set all modes and options on a debug.
 192  *
 193  * MT-Safe
 194  */
 195 #define DEBUG_ON(name)                                                         \
 196         SET_FLAG_ATOMIC(&(name)->flags, DEBUG_MODE_ALL | DEBUG_OPT_ALL)
 197
 198 /*
 199  * Map a vty node to the correct debugging mode flags. FRR behaves such that a
 200  * debug statement issued under the config node persists to the config file,
 201  * whereas the same debug statement issued from the enable node only persists
 202  * for the current session.
 203  *
 204  * MT-Safe
 205  */
 206 #define DEBUG_NODE2MODE(vtynode)                                               \
 207         (((vtynode) == CONFIG_NODE) ? DEBUG_MODE_ALL : DEBUG_MODE_TERM)
 208
 209 /*
 210  * Debug at the given level to the default logging destination.
 211  *
 212  * MT-Safe
 213  */
 214 #define DEBUG(level, name, fmt, ...)                                           \
 215         do {                                                                   \
 216                 if (DEBUG_MODE_CHECK(name, DEBUG_MODE_ALL))                    \
 217                         zlog_##level(fmt, ##__VA_ARGS__);                      \
 218         } while (0)
 219
 220 /* Convenience macros for the various levels. */
 221 #define DEBUGE(name, fmt, ...) DEBUG(err, name, fmt, ##__VA_ARGS__)
 222 #define DEBUGW(name, fmt, ...) DEBUG(warn, name, fmt, ##__VA_ARGS__)
 223 #define DEBUGI(name, fmt, ...) DEBUG(info, name, fmt, ##__VA_ARGS__)
 224 #define DEBUGN(name, fmt, ...) DEBUG(notice, name, fmt, ##__VA_ARGS__)
 225 #define DEBUGD(name, fmt, ...) DEBUG(debug, name, fmt, ##__VA_ARGS__)
 226
 227 /*
 228  * Optional initializer for debugging. Highly recommended.
 229  *
 230  * This function installs common debugging commands and allows the caller to
 231  * specify callbacks to take when these commands are issued, allowing the
 232  * caller to respond to events such as a request to turn off all debugs.
 233  *
 234  * MT-Safe
 235  */
 236 void debug_init(const struct debug_callbacks *cb);
 237
 238 #ifdef __cplusplus
 239 }
 240 #endif
 241
 242 #endif /* _FRRDEBUG_H */