lib/ferr.h

   1 /*
   2  * Copyright (c) 2015-16  David Lamparter, for NetDEF, Inc.
   3  *
   4  * Permission to use, copy, modify, and distribute this software for any
   5  * purpose with or without fee is hereby granted, provided that the above
   6  * copyright notice and this permission notice appear in all copies.
   7  *
   8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  15  */
  16
  17 #ifndef _FRR_FERR_H
  18 #define _FRR_FERR_H
  19
  20 /***********************************************************
  21  * scroll down to the end of this file for a full example! *
  22  ***********************************************************/
  23
  24 #include <stdint.h>
  25 #include <limits.h>
  26 #include <errno.h>
  27
  28 #include "vty.h"
  29
  30 #ifdef __cplusplus
  31 extern "C" {
  32 #endif
  33
  34 /* return type when this error indication stuff is used.
  35  *
  36  * guaranteed to have boolean evaluation to "false" when OK, "true" when error
  37  * (i.e. can be changed to pointer in the future if necessary)
  38  *
  39  * For checking, always use "if (value)", nothing else.
  40  * Do _NOT_ use any integer constant (!= 0), or sign check (< 0).
  41  */
  42 typedef int ferr_r;
  43
  44 /* rough category of error indication */
  45 enum ferr_kind {
  46         /* no error */
  47         FERR_OK = 0,
  48
  49         /* something isn't the way it's supposed to be.
  50          * (things that might otherwise be asserts, really)
  51          */
  52         FERR_CODE_BUG,
  53
  54         /* user-supplied parameters don't make sense or is inconsistent
  55          * if you can express a rule for it (e.g. "holdtime > 2 * keepalive"),
  56          * it's this category.
  57          */
  58         FERR_CONFIG_INVALID,
  59
  60         /* user-supplied parameters don't line up with reality
  61          * (IP address or interface not available, etc.)
  62          * NB: these are really TODOs where the code needs to be fixed to
  63          * respond to future changes!
  64          */
  65         FERR_CONFIG_REALITY,
  66
  67         /* out of some system resource (probably memory)
  68          * aka "you didn't spend enough money error" */
  69         FERR_RESOURCE,
  70
  71         /* system error (permission denied, etc.) */
  72         FERR_SYSTEM,
  73
  74         /* error return from some external library
  75          * (FERR_SYSTEM and FERR_LIBRARY are not strongly distinct) */
  76         FERR_LIBRARY,
  77 };
  78
  79 struct ferr {
  80         /* code location */
  81         const char *file;
  82         const char *func;
  83         int line;
  84
  85         enum ferr_kind kind;
  86
  87         /* unique_id is calculated as a checksum of source filename and error
  88          * message format (*before* calling vsnprintf).  Line number and
  89          * function name are not used; this keeps the number reasonably static
  90          * across changes.
  91          */
  92         uint32_t unique_id;
  93
  94         char message[384];
  95
  96         /* valid if != 0.  note "errno" might be preprocessor foobar. */
  97         int errno_val;
  98         /* valid if pathname[0] != '\0' */
  99         char pathname[PATH_MAX];
 100 };
 101
 102 /* Numeric ranges assigned to daemons for use as error codes. */
 103 #define BABEL_FERR_START    0x01000001
 104 #define BABEL_FRRR_END      0x01FFFFFF
 105 #define BGP_FERR_START      0x02000001
 106 #define BGP_FERR_END        0x02FFFFFF
 107 #define EIGRP_FERR_START    0x03000001
 108 #define EIGRP_FERR_END      0x03FFFFFF
 109 #define ISIS_FERR_START     0x04000001
 110 #define ISIS_FERR_END       0x04FFFFFF
 111 #define LDP_FERR_START      0x05000001
 112 #define LDP_FERR_END        0x05FFFFFF
 113 #define LIB_FERR_START      0x06000001
 114 #define LIB_FERR_END        0x06FFFFFF
 115 #define NHRP_FERR_START     0x07000001
 116 #define NHRP_FERR_END       0x07FFFFFF
 117 #define OSPF_FERR_START     0x08000001
 118 #define OSPF_FERR_END       0x08FFFFFF
 119 #define OSPFV3_FERR_START   0x09000001
 120 #define OSPFV3_FERR_END     0x09FFFFFF
 121 #define PBR_FERR_START      0x0A000001
 122 #define PBR_FERR_END        0x0AFFFFFF
 123 #define PIM_FERR_START      0x0B000001
 124 #define PIM_FERR_STOP       0x0BFFFFFF
 125 #define RIP_FERR_START      0x0C000001
 126 #define RIP_FERR_STOP       0x0CFFFFFF
 127 #define RIPNG_FERR_START    0x0D000001
 128 #define RIPNG_FERR_STOP     0x0DFFFFFF
 129 #define SHARP_FERR_START    0x0E000001
 130 #define SHARP_FERR_END      0x0EFFFFFF
 131 #define VTYSH_FERR_START    0x0F000001
 132 #define VTYSH_FRR_END       0x0FFFFFFF
 133 #define WATCHFRR_FERR_START 0x10000001
 134 #define WATCHFRR_FERR_END   0x10FFFFFF
 135 #define PATH_FERR_START     0x11000001
 136 #define PATH_FERR_END       0x11FFFFFF
 137 #define ZEBRA_FERR_START    0xF1000001
 138 #define ZEBRA_FERR_END      0xF1FFFFFF
 139 #define END_FERR            0xFFFFFFFF
 140
 141 struct log_ref {
 142         /* Unique error code displayed to end user as a reference. -1 means
 143          * this is an uncoded error that does not have reference material. */
 144         uint32_t code;
 145         /* Ultra brief title */
 146         const char *title;
 147         /* Brief description of error */
 148         const char *description;
 149         /* Remedial suggestion */
 150         const char *suggestion;
 151 };
 152
 153 void log_ref_add(struct log_ref *ref);
 154 struct log_ref *log_ref_get(uint32_t code);
 155 void log_ref_display(struct vty *vty, uint32_t code, bool json);
 156
 157 /*
 158  * This function should be called by the
 159  * code in libfrr.c
 160  */
 161 void log_ref_init(void);
 162 void log_ref_fini(void);
 163 void log_ref_vty_init(void);
 164
 165 /* get error details.
 166  *
 167  * NB: errval/ferr_r does NOT carry the full error information.  It's only
 168  * passed around for future API flexibility.  ferr_get_last always returns
 169  * the last error set in the current thread.
 170  */
 171 const struct ferr *ferr_get_last(ferr_r errval);
 172
 173 /*
 174  * Can optionally be called at strategic locations.
 175  * Always returns 0.
 176  */
 177 ferr_r ferr_clear(void);
 178
 179 /* do NOT call these functions directly.  only for macro use! */
 180 ferr_r ferr_set_internal(const char *file, int line, const char *func,
 181                          enum ferr_kind kind, const char *text, ...)
 182         PRINTFRR(5, 6);
 183 ferr_r ferr_set_internal_ext(const char *file, int line, const char *func,
 184                              enum ferr_kind kind, const char *pathname,
 185                              int errno_val, const char *text, ...)
 186         PRINTFRR(7, 8);
 187
 188 #define ferr_ok() 0
 189
 190 /* Report an error.
 191  *
 192  * If you need to do cleanup (free memory, etc.), save the return value in a
 193  * variable of type ferr_r.
 194  *
 195  * Don't put a \n at the end of the error message.
 196  */
 197 #define ferr_code_bug(...)                                                     \
 198         ferr_set_internal(__FILE__, __LINE__, __func__, FERR_CODE_BUG,         \
 199                           __VA_ARGS__)
 200 #define ferr_cfg_invalid(...)                                                  \
 201         ferr_set_internal(__FILE__, __LINE__, __func__, FERR_CONFIG_INVALID,   \
 202                           __VA_ARGS__)
 203 #define ferr_cfg_reality(...)                                                  \
 204         ferr_set_internal(__FILE__, __LINE__, __func__, FERR_CONFIG_REALITY,   \
 205                           __VA_ARGS__)
 206 #define ferr_cfg_resource(...)                                                 \
 207         ferr_set_internal(__FILE__, __LINE__, __func__, FERR_RESOURCE,         \
 208                           __VA_ARGS__)
 209 #define ferr_system(...)                                                       \
 210         ferr_set_internal(__FILE__, __LINE__, __func__, FERR_SYSTEM,           \
 211                           __VA_ARGS__)
 212 #define ferr_library(...)                                                      \
 213         ferr_set_internal(__FILE__, __LINE__, __func__, FERR_LIBRARY,          \
 214                           __VA_ARGS__)
 215
 216 /* extended information variants */
 217 #define ferr_system_errno(...)                                                 \
 218         ferr_set_internal_ext(__FILE__, __LINE__, __func__, FERR_SYSTEM, NULL, \
 219                               errno, __VA_ARGS__)
 220 #define ferr_system_path_errno(path, ...)                                      \
 221         ferr_set_internal_ext(__FILE__, __LINE__, __func__, FERR_SYSTEM, path, \
 222                               errno, __VA_ARGS__)
 223
 224 #include "vty.h"
 225 /* print error message to vty;  $ERR is replaced by the error's message */
 226 void vty_print_error(struct vty *vty, ferr_r err, const char *msg, ...)
 227         PRINTFRR(3, 4);
 228
 229 #define CMD_FERR_DO(func, action, ...)                                         \
 230         do {                                                                   \
 231                 ferr_r cmd_retval = func;                                      \
 232                 if (cmd_retval) {                                              \
 233                         vty_print_error(vty, cmd_retval, __VA_ARGS__);         \
 234                         action;                                                \
 235                 }                                                              \
 236         } while (0)
 237
 238 #define CMD_FERR_RETURN(func, ...)                                             \
 239         CMD_FERR_DO(func, return CMD_WARNING_CONFIG_FAILED, __VA_ARGS__)
 240 #define CMD_FERR_GOTO(func, label, ...)                                        \
 241         CMD_FERR_DO(func, goto label, __VA_ARGS__)
 242
 243 /* example: uses bogus #define to keep indent.py happy */
 244 #ifdef THIS_IS_AN_EXAMPLE
 245 ferr_r foo_bar_set(struct object *obj, int bar)
 246 {
 247         if (bar < 1 || bar >= 100)
 248                 return ferr_config_invalid("bar setting (%d) must be 0<x<100",
 249                                            bar);
 250         obj->bar = bar;
 251         if (ioctl(obj->fd, bar))
 252                 return ferr_system_errno("couldn't set bar to %d", bar);
 253
 254         return ferr_ok();
 255 }
 256
 257 DEFUN("bla")
 258 {
 259         CMD_FERR_RETURN(foo_bar_set(obj, atoi(argv[1])),
 260                         "command failed: $ERR\n");
 261         return CMD_SUCCESS;
 262 }
 263
 264 #endif /* THIS_IS_AN_EXAMPLE */
 265
 266 #ifdef __cplusplus
 267 }
 268 #endif
 269
 270 #endif /* _FERR_H */