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/*-
* Copyright (c) 2009 Isilon Inc http://www.isilon.com/
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
/**
* @file
*
* Main header for failpoint facility.
*/
#ifndef _SYS_FAIL_H_
#define _SYS_FAIL_H_
#include <sys/param.h>
#include <sys/cdefs.h>
#include <sys/linker_set.h>
#include <sys/queue.h>
#include <sys/sysctl.h>
/**
* Failpoint return codes, used internally.
* @ingroup failpoint_private
*/
enum fail_point_return_code {
FAIL_POINT_RC_CONTINUE = 0, /**< Continue with normal execution */
FAIL_POINT_RC_RETURN, /**< FP evaluated to 'return' */
FAIL_POINT_RC_QUEUED, /**< sleep_fn will be called */
};
struct fail_point_entry;
TAILQ_HEAD(fail_point_entries, fail_point_entry);
/**
* Internal failpoint structure, tracking all the current details of the
* failpoint. This structure is the core component shared between the
* failure-injection code and the user-interface.
* @ingroup failpoint_private
*/
struct fail_point {
const char *fp_name; /**< name of fail point */
const char *fp_location; /**< file:line of fail point */
struct fail_point_entries fp_entries; /**< list of entries */
int fp_flags;
void (*fp_sleep_fn)(void *); /**< Function to call at end of
* sleep for sleep failpoints */
void *fp_sleep_arg; /**< Arg for sleep_fn */
};
#define FAIL_POINT_DYNAMIC_NAME 0x01 /**< Must free name on destroy */
__BEGIN_DECLS
/* Private failpoint eval function -- use fail_point_eval() instead. */
enum fail_point_return_code fail_point_eval_nontrivial(struct fail_point *,
int *ret);
/**
* @addtogroup failpoint
* @{
*/
/*
* Initialize a fail-point. The name is formed in printf-like fashion
* from "fmt" and the subsequent arguments.
* Pair with fail_point_destroy().
*/
void fail_point_init(struct fail_point *, const char *fmt, ...)
__printflike(2, 3);
/**
* Set the sleep function for a fail point
* If sleep_fn is specified, then FAIL_POINT_SLEEP will result in a
* (*fp->sleep_fn)(fp->sleep_arg) call by the timer thread. Otherwise,
* if sleep_fn is NULL (default), then FAIL_POINT_SLEEP will result in the
* fail_point_eval() call sleeping.
*/
static __inline void
fail_point_sleep_set_func(struct fail_point *fp, void (*sleep_fn)(void *))
{
fp->fp_sleep_fn = sleep_fn;
}
/**
* Set the argument for the sleep function for a fail point
*/
static __inline void
fail_point_sleep_set_arg(struct fail_point *fp, void *sleep_arg)
{
fp->fp_sleep_arg = sleep_arg;
}
/**
* Free the resources used by a fail-point. Pair with fail_point_init().
*/
void fail_point_destroy(struct fail_point *);
/**
* Evaluate a failpoint.
*/
static __inline enum fail_point_return_code
fail_point_eval(struct fail_point *fp, int *ret)
{
if (TAILQ_EMPTY(&fp->fp_entries)) {
return (FAIL_POINT_RC_CONTINUE);
}
return (fail_point_eval_nontrivial(fp, ret));
}
__END_DECLS
/* Declare a fail_point and its sysctl in a function. */
#define _FAIL_POINT_NAME(name) _fail_point_##name
#define _FAIL_POINT_LOCATION() "(" __FILE__ ":" __XSTRING(__LINE__) ")"
/**
* Instantiate a failpoint which returns "value" from the function when triggered.
* @param parent The parent sysctl under which to locate the sysctl
* @param name The name of the failpoint in the sysctl tree (and printouts)
* @return Instantly returns the return("value") specified in the
* failpoint, if triggered.
*/
#define KFAIL_POINT_RETURN(parent, name) \
KFAIL_POINT_CODE(parent, name, return RETURN_VALUE)
/**
* Instantiate a failpoint which returns (void) from the function when triggered.
* @param parent The parent sysctl under which to locate the sysctl
* @param name The name of the failpoint in the sysctl tree (and printouts)
* @return Instantly returns void, if triggered in the failpoint.
*/
#define KFAIL_POINT_RETURN_VOID(parent, name) \
KFAIL_POINT_CODE(parent, name, return)
/**
* Instantiate a failpoint which sets an error when triggered.
* @param parent The parent sysctl under which to locate the sysctl
* @param name The name of the failpoint in the sysctl tree (and printouts)
* @param error_var A variable to set to the failpoint's specified
* return-value when triggered
*/
#define KFAIL_POINT_ERROR(parent, name, error_var) \
KFAIL_POINT_CODE(parent, name, (error_var) = RETURN_VALUE)
/**
* Instantiate a failpoint which sets an error and then goes to a
* specified label in the function when triggered.
* @param parent The parent sysctl under which to locate the sysctl
* @param name The name of the failpoint in the sysctl tree (and printouts)
* @param error_var A variable to set to the failpoint's specified
* return-value when triggered
* @param label The location to goto when triggered.
*/
#define KFAIL_POINT_GOTO(parent, name, error_var, label) \
KFAIL_POINT_CODE(parent, name, (error_var) = RETURN_VALUE; goto label)
/**
* Instantiate a failpoint which runs arbitrary code when triggered.
* @param parent The parent sysctl under which to locate the sysctl
* @param name The name of the failpoint in the sysctl tree
* (and printouts)
* @param code The arbitrary code to run when triggered. Can reference
* "RETURN_VALUE" if desired to extract the specified
* user return-value when triggered. Note that this is
* implemented with a do-while loop so be careful of
* break and continue statements.
*/
#define KFAIL_POINT_CODE(parent, name, code) \
do { \
int RETURN_VALUE; \
static struct fail_point _FAIL_POINT_NAME(name) = { \
#name, \
_FAIL_POINT_LOCATION(), \
TAILQ_HEAD_INITIALIZER(_FAIL_POINT_NAME(name).fp_entries), \
0, \
NULL, NULL, \
}; \
SYSCTL_OID(parent, OID_AUTO, name, \
CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_MPSAFE, \
&_FAIL_POINT_NAME(name), 0, fail_point_sysctl, \
"A", ""); \
\
if (__predict_false( \
fail_point_eval(&_FAIL_POINT_NAME(name), &RETURN_VALUE))) { \
\
code; \
\
} \
} while (0)
/**
* @}
* (end group failpoint)
*/
#ifdef _KERNEL
int fail_point_sysctl(SYSCTL_HANDLER_ARGS);
/* The fail point sysctl tree. */
SYSCTL_DECL(_debug_fail_point);
#define DEBUG_FP _debug_fail_point
#endif
#endif /* _SYS_FAIL_H_ */
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