/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2009-2019 Dell EMC Isilon 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>
#include <sys/condvar.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/systm.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;
struct fail_point_setting;
/**
* 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 */
volatile int fp_ref_cnt; /**
* protects fp_setting: while holding
* a ref, fp_setting points to an
* unfreed fail_point_setting
*/
struct fail_point_setting * volatile fp_setting;
int fp_flags;
/**< Function to call before sleep or pause */
void (*fp_pre_sleep_fn)(void *);
/**< Arg for fp_pre_sleep_fn */
void *fp_pre_sleep_arg;
/**< Function to call after waking from sleep or pause */
void (*fp_post_sleep_fn)(void *);
/**< Arg for fp_post_sleep_fn */
void *fp_post_sleep_arg;
struct callout *fp_callout;
};
#define FAIL_POINT_DYNAMIC_NAME 0x01 /**< Must free name on destroy */
/**< Use timeout path for sleep instead of msleep */
#define FAIL_POINT_USE_TIMEOUT_PATH 0x02
/**< If fail point is set to sleep, replace the sleep call with delay */
#define FAIL_POINT_NONSLEEPABLE 0x04
#define FAIL_POINT_CV_DESC "fp cv no iterators"
#define FAIL_POINT_IS_OFF(fp) (__predict_true((fp)->fp_setting == NULL) || \
__predict_true(fail_point_is_off(fp)))
__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);
/* Return true iff this fail point is set to off, false otherwise */
bool fail_point_is_off(struct fail_point *fp);
/**
* Set the pre-sleep function for a fail point
* If fp_post_sleep_fn is specified, then FAIL_POINT_SLEEP will result in a
* (*fp->fp_pre_sleep_fn)(fp->fp_pre_sleep_arg) call by the thread.
*/
static inline void
fail_point_sleep_set_pre_func(struct fail_point *fp, void (*sleep_fn)(void *))
{
fp->fp_pre_sleep_fn = sleep_fn;
}
static inline void
fail_point_sleep_set_pre_arg(struct fail_point *fp, void *sleep_arg)
{
fp->fp_pre_sleep_arg = sleep_arg;
}
/**
* Set the post-sleep function. This will be passed to timeout if we take
* the timeout path. This must be set if you sleep using the timeout path.
*/
static inline void
fail_point_sleep_set_post_func(struct fail_point *fp, void (*sleep_fn)(void *))
{
fp->fp_post_sleep_fn = sleep_fn;
}
static inline void
fail_point_sleep_set_post_arg(struct fail_point *fp, void *sleep_arg)
{
fp->fp_post_sleep_arg = sleep_arg;
}
void fail_point_alloc_callout(struct fail_point *);
/**
* If the FAIL_POINT_USE_TIMEOUT flag is set on a failpoint, then
* FAIL_POINT_SLEEP will result in a call to callout_reset instead of
* msleep. Note that if you sleep while this flag is set, you must
* set fp_post_sleep_fn or an error will occur upon waking.
*/
static inline void
fail_point_use_timeout_path(struct fail_point *fp, bool use_timeout,
void (*post_sleep_fn)(void *))
{
KASSERT(!use_timeout || post_sleep_fn != NULL ||
(post_sleep_fn == NULL && fp->fp_post_sleep_fn != NULL),
("Setting fp to use timeout, but not setting post_sleep_fn\n"));
if (use_timeout) {
fail_point_alloc_callout(fp);
fp->fp_flags |= FAIL_POINT_USE_TIMEOUT_PATH;
} else
fp->fp_flags &= ~FAIL_POINT_USE_TIMEOUT_PATH;
if (post_sleep_fn != NULL)
fp->fp_post_sleep_fn = post_sleep_fn;
}
/**
* 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 (__predict_true(fp->fp_setting == NULL))
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 KFAIL_POINT_DECLARE(name) \
extern struct fail_point _FAIL_POINT_NAME(name)
#define _FAIL_POINT_NAME(name) _fail_point_##name
#define _FAIL_POINT_LOCATION() "(" __FILE__ ":" __XSTRING(__LINE__) ")"
#define KFAIL_POINT_DEFINE(parent, name, flags) \
struct fail_point _FAIL_POINT_NAME(name) = { \
.fp_name = #name, \
.fp_location = _FAIL_POINT_LOCATION(), \
.fp_ref_cnt = 0, \
.fp_setting = NULL, \
.fp_flags = (flags), \
.fp_pre_sleep_fn = NULL, \
.fp_pre_sleep_arg = NULL, \
.fp_post_sleep_fn = NULL, \
.fp_post_sleep_arg = NULL, \
}; \
SYSCTL_OID(parent, OID_AUTO, name, \
CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_MPSAFE, \
&_FAIL_POINT_NAME(name), 0, fail_point_sysctl, \
"A", ""); \
SYSCTL_OID(parent, OID_AUTO, status_##name, \
CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, \
&_FAIL_POINT_NAME(name), 0, \
fail_point_sysctl_status, "A", "");
#define _FAIL_POINT_INIT(parent, name, flags) \
static KFAIL_POINT_DEFINE(parent, name, flags)
#define _FAIL_POINT_EVAL(name, cond, code...) \
int RETURN_VALUE; \
\
if (__predict_false(cond && \
fail_point_eval(&_FAIL_POINT_NAME(name), &RETURN_VALUE))) { \
\
code; \
\
}
#define KFAIL_POINT_EVAL(name, code...) \
_FAIL_POINT_EVAL(name, true, code)
/**
* Instantiate a failpoint which returns "RETURN_VALUE" from the function
* when triggered.
* @param parent The parent sysctl under which to locate the fp's 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 sets its pre- and post-sleep callback
* mechanisms.
* @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 pre_func Function pointer to the pre-sleep function, which will be
* called directly before going to sleep.
* @param pre_arg Argument to the pre-sleep function
* @param post_func Function pointer to the pot-sleep function, which will be
* called directly before going to sleep.
* @param post_arg Argument to the post-sleep function
*/
#define KFAIL_POINT_SLEEP_CALLBACKS(parent, name, pre_func, pre_arg, \
post_func, post_arg) \
KFAIL_POINT_CODE_SLEEP_CALLBACKS(parent, name, pre_func, \
pre_arg, post_func, post_arg, return RETURN_VALUE)
/**
* Instantiate a failpoint which runs arbitrary code when triggered, and sets
* its pre- and post-sleep callback mechanisms
* @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 pre_func Function pointer to the pre-sleep function, which will be
* called directly before going to sleep.
* @param pre_arg Argument to the pre-sleep function
* @param post_func Function pointer to the pot-sleep function, which will be
* called directly before going to sleep.
* @param post_arg Argument to the post-sleep function
* @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_SLEEP_CALLBACKS(parent, name, pre_func, pre_arg, \
post_func, post_arg, code...) \
do { \
_FAIL_POINT_INIT(parent, name) \
_FAIL_POINT_NAME(name).fp_pre_sleep_fn = pre_func; \
_FAIL_POINT_NAME(name).fp_pre_sleep_arg = pre_arg; \
_FAIL_POINT_NAME(name).fp_post_sleep_fn = post_func; \
_FAIL_POINT_NAME(name).fp_post_sleep_arg = post_arg; \
_FAIL_POINT_EVAL(name, true, code) \
} while (0)
/**
* 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 { \
_FAIL_POINT_INIT(parent, name, 0) \
_FAIL_POINT_EVAL(name, true, code) \
} while (0)
#define KFAIL_POINT_CODE_FLAGS(parent, name, flags, code...) \
do { \
_FAIL_POINT_INIT(parent, name, flags) \
_FAIL_POINT_EVAL(name, true, code) \
} while (0)
#define KFAIL_POINT_CODE_COND(parent, name, cond, flags, code...) \
do { \
_FAIL_POINT_INIT(parent, name, flags) \
_FAIL_POINT_EVAL(name, cond, code) \
} while (0)
/**
* @}
* (end group failpoint)
*/
#ifdef _KERNEL
int fail_point_sysctl(SYSCTL_HANDLER_ARGS);
int fail_point_sysctl_status(SYSCTL_HANDLER_ARGS);
/* The fail point sysctl tree. */
SYSCTL_DECL(_debug_fail_point);
#define DEBUG_FP _debug_fail_point
#endif
#endif /* _SYS_FAIL_H_ */
