[mirror_frr.git] / lib / ferr.h

/*
 * Copyright (c) 2015-16  David Lamparter, for NetDEF, Inc.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#ifndef _FRR_FERR_H
#define _FRR_FERR_H

/***********************************************************
 * scroll down to the end of this file for a full example! *
 ***********************************************************/

#include <stdint.h>
#include <limits.h>
#include <errno.h>

/* return type when this error indication stuff is used.
 *
 * guaranteed to have boolean evaluation to "false" when OK, "true" when error
 * (i.e. can be changed to pointer in the future if neccessary)
 *
 * For checking, always use "if (value)", nothing else.
 * Do _NOT_ use any integer constant (!= 0), or sign check (< 0).
 */
typedef int ferr_r;

/* rough category of error indication */
enum ferr_kind {
	/* no error */
	FERR_OK = 0,

	/* something isn't the way it's supposed to be.
	 * (things that might otherwise be asserts, really)
	 */
	FERR_CODE_BUG,

	/* user-supplied parameters don't make sense or is inconsistent
	 * if you can express a rule for it (e.g. "holdtime > 2 * keepalive"),
	 * it's this category.
	 */
	FERR_CONFIG_INVALID,

	/* user-supplied parameters don't line up with reality
	 * (IP address or interface not available, etc.)
	 * NB: these are really TODOs where the code needs to be fixed to
	 * respond to future changes!
	 */
	FERR_CONFIG_REALITY,

	/* out of some system resource (probably memory)
	 * aka "you didn't spend enough money error" */
	FERR_RESOURCE,

	/* system error (permission denied, etc.) */
	FERR_SYSTEM,

	/* error return from some external library
	 * (FERR_SYSTEM and FERR_LIBRARY are not strongly distinct) */
	FERR_LIBRARY,
};

struct ferr {
	/* code location */
	const char *file;
	const char *func;
	int line;

	enum ferr_kind kind;

	/* unique_id is calculated as a checksum of source filename and error
	 * message format (*before* calling vsnprintf).  Line number and
	 * function name are not used; this keeps the number reasonably static
	 * across changes.
	 */
	uint32_t unique_id;

	char message[384];

	/* valid if != 0.  note "errno" might be preprocessor foobar. */
	int errno_val;
	/* valid if pathname[0] != '\0' */
	char pathname[PATH_MAX];
};

/* get error details.
 *
 * NB: errval/ferr_r does NOT carry the full error information.  It's only
 * passed around for future API flexibility.  ferr_get_last always returns
 * the last error set in the current thread.
 */
const struct ferr *ferr_get_last(ferr_r errval);

/* can optionally be called at strategic locations.
 * always returns 0. */
ferr_r ferr_clear(void);

/* do NOT call these functions directly.  only for macro use! */
ferr_r ferr_set_internal(const char *file, int line, const char *func,
			 enum ferr_kind kind, const char *text, ...);
ferr_r ferr_set_internal_ext(const char *file, int line, const char *func,
			     enum ferr_kind kind, const char *pathname,
			     int errno_val, const char *text, ...);

#define ferr_ok() 0

/* Report an error.
 *
 * If you need to do cleanup (free memory, etc.), save the return value in a
 * variable of type ferr_r.
 *
 * Don't put a \n at the end of the error message.
 */
#define ferr_code_bug(...)                                                     \
	ferr_set_internal(__FILE__, __LINE__, __func__, FERR_CODE_BUG,         \
			  __VA_ARGS__)
#define ferr_cfg_invalid(...)                                                  \
	ferr_set_internal(__FILE__, __LINE__, __func__, FERR_CONFIG_INVALID,   \
			  __VA_ARGS__)
#define ferr_cfg_reality(...)                                                  \
	ferr_set_internal(__FILE__, __LINE__, __func__, FERR_CONFIG_REALITY,   \
			  __VA_ARGS__)
#define ferr_cfg_resource(...)                                                 \
	ferr_set_internal(__FILE__, __LINE__, __func__, FERR_RESOURCE,         \
			  __VA_ARGS__)
#define ferr_system(...)                                                       \
	ferr_set_internal(__FILE__, __LINE__, __func__, FERR_SYSTEM,           \
			  __VA_ARGS__)
#define ferr_library(...)                                                      \
	ferr_set_internal(__FILE__, __LINE__, __func__, FERR_LIBRARY,          \
			  __VA_ARGS__)

/* extended information variants */
#define ferr_system_errno(...)                                                 \
	ferr_set_internal_ext(__FILE__, __LINE__, __func__, FERR_SYSTEM, NULL, \
			      errno, __VA_ARGS__)
#define ferr_system_path_errno(path, ...)                                      \
	ferr_set_internal_ext(__FILE__, __LINE__, __func__, FERR_SYSTEM, path, \
			      errno, __VA_ARGS__)

#include "vty.h"
/* print error message to vty;  $ERR is replaced by the error's message */
void vty_print_error(struct vty *vty, ferr_r err, const char *msg, ...);

#define CMD_FERR_DO(func, action, ...)                                         \
	do {                                                                   \
		ferr_r cmd_retval = func;                                      \
		if (cmd_retval) {                                              \
			vty_print_error(vty, cmd_retval, __VA_ARGS__);         \
			action;                                                \
		}                                                              \
	} while (0)

#define CMD_FERR_RETURN(func, ...)                                             \
	CMD_FERR_DO(func, return CMD_WARNING_CONFIG_FAILED, __VA_ARGS__)
#define CMD_FERR_GOTO(func, label, ...)                                        \
	CMD_FERR_DO(func, goto label, __VA_ARGS__)

/* example: uses bogus #define to keep indent.py happy */
#ifdef THIS_IS_AN_EXAMPLE
ferr_r foo_bar_set(struct object *obj, int bar)
{
	if (bar < 1 || bar >= 100)
		return ferr_config_invalid("bar setting (%d) must be 0<x<100",
					   bar);
	obj->bar = bar;
	if (ioctl(obj->fd, bar))
		return ferr_system_errno("couldn't set bar to %d", bar);

	return ferr_ok();
}

DEFUN("bla")
{
	CMD_FERR_RETURN(foo_bar_set(obj, atoi(argv[1])),
			"command failed: $ERR\n");
	return CMD_SUCCESS;
}

#endif /* THIS_IS_AN_EXAMPLE */

#endif /* _FERR_H */
Commit	Line	Data
3155489a DL	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	/* return type when this error indication stuff is used.
	29	*
	30	* guaranteed to have boolean evaluation to "false" when OK, "true" when error
	31	* (i.e. can be changed to pointer in the future if neccessary)
	32	*
	33	* For checking, always use "if (value)", nothing else.
	34	* Do _NOT_ use any integer constant (!= 0), or sign check (< 0).
	35	*/
	36	typedef int ferr_r;
	37
	38	/* rough category of error indication */
	39	enum ferr_kind {
	40	/* no error */
	41	FERR_OK = 0,
	42
	43	/* something isn't the way it's supposed to be.
	44	* (things that might otherwise be asserts, really)
	45	*/
	46	FERR_CODE_BUG,
	47
	48	/* user-supplied parameters don't make sense or is inconsistent
	49	* if you can express a rule for it (e.g. "holdtime > 2 * keepalive"),
	50	* it's this category.
	51	*/
	52	FERR_CONFIG_INVALID,
	53
	54	/* user-supplied parameters don't line up with reality
	55	* (IP address or interface not available, etc.)
	56	* NB: these are really TODOs where the code needs to be fixed to
	57	* respond to future changes!
	58	*/
	59	FERR_CONFIG_REALITY,
	60
	61	/* out of some system resource (probably memory)
	62	* aka "you didn't spend enough money error" */
	63	FERR_RESOURCE,
	64
65	/* system error (permission denied, etc.) */
66	FERR_SYSTEM,
67
68	/* error return from some external library
69	* (FERR_SYSTEM and FERR_LIBRARY are not strongly distinct) */
70	FERR_LIBRARY,
71	};
72
73	struct ferr {
74	/* code location */
75	const char *file;
76	const char *func;
77	int line;
78
79	enum ferr_kind kind;
80
81	/* unique_id is calculated as a checksum of source filename and error
82	* message format (before calling vsnprintf). Line number and
83	* function name are not used; this keeps the number reasonably static
84	* across changes.
85	*/
86	uint32_t unique_id;
87
88	char message[384];
89
90	/* valid if != 0. note "errno" might be preprocessor foobar. */
91	int errno_val;
92	/* valid if pathname[0] != '\0' */
93	char pathname[PATH_MAX];
94	};
95
96	/* get error details.
97	*
98	* NB: errval/ferr_r does NOT carry the full error information. It's only
99	* passed around for future API flexibility. ferr_get_last always returns
100	* the last error set in the current thread.
101	*/
102	const struct ferr *ferr_get_last(ferr_r errval);
103
104	/* can optionally be called at strategic locations.
105	* always returns 0. */
106	ferr_r ferr_clear(void);
107
108	/* do NOT call these functions directly. only for macro use! */
109	ferr_r ferr_set_internal(const char file, int line, const char func,
996c9314	110	enum ferr_kind kind, const char *text, ...);
3155489a	111	ferr_r ferr_set_internal_ext(const char file, int line, const char func,
996c9314 LB	112	enum ferr_kind kind, const char *pathname,
996c9314 LB	113	int errno_val, const char *text, ...);
3155489a	114
996c9314	115	#define ferr_ok() 0
3155489a DL	116
	117	/* Report an error.
	118	*
	119	* If you need to do cleanup (free memory, etc.), save the return value in a
	120	* variable of type ferr_r.
	121	*
	122	* Don't put a \n at the end of the error message.
	123	*/
996c9314 LB	124	#define ferr_code_bug(...) \
	125	ferr_set_internal(__FILE__, __LINE__, __func__, FERR_CODE_BUG, \
	126	__VA_ARGS__)
	127	#define ferr_cfg_invalid(...) \
	128	ferr_set_internal(__FILE__, __LINE__, __func__, FERR_CONFIG_INVALID, \
	129	__VA_ARGS__)
	130	#define ferr_cfg_reality(...) \
	131	ferr_set_internal(__FILE__, __LINE__, __func__, FERR_CONFIG_REALITY, \
	132	__VA_ARGS__)
	133	#define ferr_cfg_resource(...) \
	134	ferr_set_internal(__FILE__, __LINE__, __func__, FERR_RESOURCE, \
	135	__VA_ARGS__)
	136	#define ferr_system(...) \
	137	ferr_set_internal(__FILE__, __LINE__, __func__, FERR_SYSTEM, \
	138	__VA_ARGS__)
	139	#define ferr_library(...) \
	140	ferr_set_internal(__FILE__, __LINE__, __func__, FERR_LIBRARY, \
	141	__VA_ARGS__)
3155489a DL	142
3155489a DL	143	/* extended information variants */
996c9314 LB	144	#define ferr_system_errno(...) \
	145	ferr_set_internal_ext(__FILE__, __LINE__, __func__, FERR_SYSTEM, NULL, \
	146	errno, __VA_ARGS__)
	147	#define ferr_system_path_errno(path, ...) \
	148	ferr_set_internal_ext(__FILE__, __LINE__, __func__, FERR_SYSTEM, path, \
	149	errno, __VA_ARGS__)
3155489a DL	150
	151	#include "vty.h"
	152	/* print error message to vty; $ERR is replaced by the error's message */
	153	void vty_print_error(struct vty vty, ferr_r err, const char msg, ...);
	154
996c9314 LB	155	#define CMD_FERR_DO(func, action, ...) \
	156	do { \
	157	ferr_r cmd_retval = func; \
	158	if (cmd_retval) { \
	159	vty_print_error(vty, cmd_retval, __VA_ARGS__); \
	160	action; \
	161	} \
3155489a DL	162	} while (0)
3155489a DL	163
996c9314	164	#define CMD_FERR_RETURN(func, ...) \
7eb09438	165	CMD_FERR_DO(func, return CMD_WARNING_CONFIG_FAILED, __VA_ARGS__)
996c9314	166	#define CMD_FERR_GOTO(func, label, ...) \
3155489a DL	167	CMD_FERR_DO(func, goto label, __VA_ARGS__)
3155489a DL	168
e894f9fd LB	169	/* example: uses bogus #define to keep indent.py happy */
e894f9fd LB	170	#ifdef THIS_IS_AN_EXAMPLE
3155489a DL	171	ferr_r foo_bar_set(struct object *obj, int bar)
	172	{
	173	if (bar < 1 \|\| bar >= 100)
e894f9fd LB	174	return ferr_config_invalid("bar setting (%d) must be 0<x<100",
e894f9fd LB	175	bar);
3155489a	176	obj->bar = bar;
e894f9fd	177	if (ioctl(obj->fd, bar))
3155489a DL	178	return ferr_system_errno("couldn't set bar to %d", bar);
	179
	180	return ferr_ok();
	181	}
	182
	183	DEFUN("bla")
	184	{
	185	CMD_FERR_RETURN(foo_bar_set(obj, atoi(argv[1])),
996c9314	186	"command failed: $ERR\n");
3155489a DL	187	return CMD_SUCCESS;
	188	}
	189
e894f9fd	190	#endif /* THIS_IS_AN_EXAMPLE */
3155489a DL	191
3155489a DL	192	#endif /* _FERR_H */