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 /*
  28  * Debugging modes.
  29  *
  30  * FRR's convention is that a debug statement issued under the vty CONFIG_NODE
  31  * persists to the config file, whereas the same debug statement issued from
  32  * the ENABLE_NODE only persists for the current session. These are mapped to
  33  * DEBUG_MODE_CONF and DEBUG_MODE_TERM respectively.
  34  *
  35  * They are not mutually exclusive and are placed in the MSB of the flags
  36  * field in a debugging record.
  37  */
  38 #define DEBUG_MODE_TERM 0x01000000
  39 #define DEBUG_MODE_CONF 0x02000000
  40 #define DEBUG_MODE_ALL (DEBUG_MODE_TERM | DEBUG_MODE_CONF)
  41 #define DEBUG_MODE_NONE 0x00000000
  42 #define DEBUG_OPT_ALL 0x00FFFFFF
  43 #define DEBUG_OPT_NONE 0x00000000
  44
  45
  46 /*
  47  * Debugging record.
  48  *
  49  * All operations on this record exposed in this header are MT-safe.
  50  *
  51  * flags
  52  *    A bitfield with the following format (bytes high to low)
  53  *    - [0] Debugging mode field (MSB)  | Mode
  54  *    - [1] Arbitrary flag field        | Option
  55  *    - [2] Arbitrary flag field        | Option
  56  *    - [3] Arbitrary flag field (LSB)  | Option
  57  *
  58  *              ALL THESE BYTES ARE YOURS - EXCEPT MODE.
  59  *                      ATTEMPT NO BIT OPS THERE.
  60  *
  61  *    The MSB of this field determines the debug mode, Use the DEBUG_MODE*
  62  *    macros to manipulate this byte.
  63  *
  64  *    The low 3 bytes of this field may be used to store arbitrary information.
  65  *    Usually they are used to store flags that tune how detailed the logging
  66  *    for a particular debug record is. Use the DEBUG_OPT* macros to manipulate
  67  *    those bytes.
  68  *
  69  *    All operations performed on this field should be done using the macros
  70  *    later in this header file. They are guaranteed to be atomic operations
  71  *    with respect to this field. Using anything except the macros to
  72  *    manipulate the flags field in a multithreaded environment results in
  73  *    undefined behavior.
  74  *
  75  * desc
  76  *    Human-readable description of this debugging record.
  77  */
  78 struct debug {
  79         _Atomic uint32_t flags;
  80         const char *desc;
  81 };
  82
  83 /*
  84  * Callback set for debugging code.
  85  *
  86  * debug_set_all
  87  *    Function pointer to call when the user requests that all debugs have a
  88  *    mode set.
  89  */
  90 struct debug_callbacks {
  91         /*
  92          * flags
  93          *    flags to set on debug flag fields
  94          *
  95          * set
  96          *    true: set flags
  97          *    false: unset flags
  98          */
  99         void (*debug_set_all)(uint32_t flags, bool set);
 100 };
 101
 102 /*
 103  * Check if a mode is set for a debug.
 104  *
 105  * MT-Safe
 106  */
 107 #define DEBUG_MODE_CHECK(name, mode)                                           \
 108         CHECK_FLAG_ATOMIC(&(name)->flags, (mode)&DEBUG_MODE_ALL)
 109
 110 /*
 111  * Check if an option bit is set for a debug.
 112  *
 113  * MT-Safe
 114  */
 115 #define DEBUG_OPT_CHECK(name, opt)                                             \
 116         CHECK_FLAG_ATOMIC(&(name)->flags, (opt)&DEBUG_OPT_ALL)
 117
 118 /*
 119  * Check if bits are set for a debug.
 120  *
 121  * MT-Safe
 122  */
 123 #define DEBUG_FLAGS_CHECK(name, fl) CHECK_FLAG_ATOMIC(&(name)->flags, (fl))
 124
 125 /*
 126  * Set modes on a debug.
 127  *
 128  * MT-Safe
 129  */
 130 #define DEBUG_MODE_SET(name, mode, onoff)                                      \
 131         do {                                                                   \
 132                 if (onoff)                                                     \
 133                         SET_FLAG_ATOMIC(&(name)->flags,                        \
 134                                         (mode)&DEBUG_MODE_ALL);                \
 135                 else                                                           \
 136                         UNSET_FLAG_ATOMIC(&(name)->flags,                      \
 137                                           (mode)&DEBUG_MODE_ALL);              \
 138         } while (0)
 139
 140 /* Convenience macros for specific set operations. */
 141 #define DEBUG_MODE_ON(name, mode) DEBUG_MODE_SET(name, mode, true)
 142 #define DEBUG_MODE_OFF(name, mode) DEBUG_MODE_SET(name, mode, false)
 143
 144 /*
 145  * Set options on a debug.
 146  *
 147  * MT-Safe
 148  */
 149 #define DEBUG_OPT_SET(name, opt, onoff)                                        \
 150         do {                                                                   \
 151                 if (onoff)                                                     \
 152                         SET_FLAG_ATOMIC(&(name)->flags, (opt)&DEBUG_OPT_ALL);  \
 153                 else                                                           \
 154                         UNSET_FLAG_ATOMIC(&(name)->flags,                      \
 155                                           (opt)&DEBUG_OPT_ALL);                \
 156         } while (0)
 157
 158 /* Convenience macros for specific set operations. */
 159 #define DEBUG_OPT_ON(name, opt) DEBUG_OPT_SET(name, opt, true)
 160 #define DEBUG_OPT_OFF(name, opt) DEBUG_OPT_SET(name, opt, true)
 161
 162 /*
 163  * Set bits on a debug.
 164  *
 165  * MT-Safe
 166  */
 167 #define DEBUG_FLAGS_SET(name, fl, onoff)                                       \
 168         do {                                                                   \
 169                 if (onoff)                                                     \
 170                         SET_FLAG_ATOMIC(&(name)->flags, (fl));                 \
 171                 else                                                           \
 172                         UNSET_FLAG_ATOMIC(&(name)->flags, (fl));               \
 173         } while (0)
 174
 175 /* Convenience macros for specific set operations. */
 176 #define DEBUG_FLAGS_ON(name, fl) DEBUG_FLAGS_SET(&(name)->flags, (type), true)
 177 #define DEBUG_FLAGS_OFF(name, fl) DEBUG_FLAGS_SET(&(name)->flags, (type), false)
 178
 179 /*
 180  * Unset all modes and options on a debug.
 181  *
 182  * MT-Safe
 183  */
 184 #define DEBUG_CLEAR(name) RESET_FLAG_ATOMIC(&(name)->flags)
 185
 186 /*
 187  * Set all modes and options on a debug.
 188  *
 189  * MT-Safe
 190  */
 191 #define DEBUG_ON(name)                                                         \
 192         SET_FLAG_ATOMIC(&(name)->flags, DEBUG_MODE_ALL | DEBUG_OPT_ALL)
 193
 194 /*
 195  * Map a vty node to the correct debugging mode flags. FRR behaves such that a
 196  * debug statement issued under the config node persists to the config file,
 197  * whereas the same debug statement issued from the enable node only persists
 198  * for the current session.
 199  *
 200  * MT-Safe
 201  */
 202 #define DEBUG_NODE2MODE(vtynode)                                               \
 203         (((vtynode) == CONFIG_NODE) ? DEBUG_MODE_ALL : DEBUG_MODE_TERM)
 204
 205 /*
 206  * Debug at the given level to the default logging destination.
 207  *
 208  * MT-Safe
 209  */
 210 #define DEBUG(level, name, fmt, ...)                                           \
 211         do {                                                                   \
 212                 if (DEBUG_MODE_CHECK(name, DEBUG_MODE_ALL))                    \
 213                         zlog_##level(fmt, ##__VA_ARGS__);                      \
 214         } while (0)
 215
 216 /* Convenience macros for the various levels. */
 217 #define DEBUGE(name, fmt, ...) DEBUG(err, name, fmt, ##__VA_ARGS__)
 218 #define DEBUGW(name, fmt, ...) DEBUG(warn, name, fmt, ##__VA_ARGS__)
 219 #define DEBUGI(name, fmt, ...) DEBUG(info, name, fmt, ##__VA_ARGS__)
 220 #define DEBUGN(name, fmt, ...) DEBUG(notice, name, fmt, ##__VA_ARGS__)
 221 #define DEBUGD(name, fmt, ...) DEBUG(debug, name, fmt, ##__VA_ARGS__)
 222
 223 /*
 224  * Optional initializer for debugging. Highly recommended.
 225  *
 226  * This function installs common debugging commands and allows the caller to
 227  * specify callbacks to take when these commands are issued, allowing the
 228  * caller to respond to events such as a request to turn off all debugs.
 229  *
 230  * MT-Safe
 231  */
 232 void debug_init(const struct debug_callbacks *cb);
 233
 234 #endif /* _FRRDEBUG_H */