cfeb7489c2
Add support for kernel fault injection using KFAIL_POINT_* macros and fail_point_* infrastructure. Add example fail point in vfs_bio.c to simulate VM buf pressure. Approved by: dfr (mentor)
261 lines
8.5 KiB
C
261 lines
8.5 KiB
C
/*-
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* Copyright (c) 2009 Isilon Inc http://www.isilon.com/
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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/**
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* @file
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*
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* Main header for failpoint facility.
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*/
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#ifndef _SYS_FAIL_H_
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#define _SYS_FAIL_H_
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#include <sys/types.h>
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#include <sys/linker_set.h>
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#include <sys/param.h>
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#include <sys/queue.h>
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#include <sys/sysctl.h>
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/**
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* Failpoint types.
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* Don't change these without changing fail_type_strings in fail.c.
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* @ingroup failpoint_private
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*/
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enum fail_point_t {
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FAIL_POINT_OFF, /**< don't fail */
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FAIL_POINT_PANIC, /**< panic */
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FAIL_POINT_RETURN, /**< return an errorcode */
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FAIL_POINT_BREAK, /**< break into the debugger */
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FAIL_POINT_PRINT, /**< print a message */
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FAIL_POINT_SLEEP, /**< sleep for some msecs */
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FAIL_POINT_INVALID, /**< placeholder */
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};
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/**
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* Failpoint return codes, used internally.
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* @ingroup failpoint_private
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*/
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enum fail_point_return_code {
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FAIL_POINT_RC_CONTINUE = 0, /**< Continue with normal execution */
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FAIL_POINT_RC_RETURN, /**< FP evaluated to 'return' */
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FAIL_POINT_RC_QUEUED, /**< sleep_fn will be called */
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};
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TAILQ_HEAD(fail_point_entries, fail_point_entry);
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/**
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* Internal failpoint structure, tracking all the current details of the
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* failpoint. This structure is the core component shared between the
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* failure-injection code and the user-interface.
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* @ingroup failpoint_private
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*/
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struct fail_point {
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const char *fp_name; /**< name of fail point */
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const char *fp_location; /**< file:line of fail point */
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struct fail_point_entries fp_entries; /**< list of entries */
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int fp_flags;
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void (*fp_sleep_fn)(void *); /**< Function to call at end of
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* sleep for sleep failpoints */
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void *fp_sleep_arg; /**< Arg for sleep_fn */
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};
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#define FAIL_POINT_DYNAMIC_NAME 0x01 /**< Must free name on destroy */
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/**
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* Internal structure tracking a single term of a complete failpoint.
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* @ingroup failpoint_private
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*/
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struct fail_point_entry {
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enum fail_point_t fe_type; /**< type of entry */
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int fe_arg; /**< argument to type (e.g. return value) */
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int fe_prob; /**< likelihood of firing in millionths */
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int fe_count; /**< number of times to fire, 0 means always */
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TAILQ_ENTRY(fail_point_entry) fe_entries; /**< next entry in fail point */
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};
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/* Private failpoint eval function -- use fail_point_eval() instead. */
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enum fail_point_return_code fail_point_eval_nontrivial(struct fail_point *,
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int *ret);
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/**
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* @addtogroup failpoint
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* @{
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*/
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/*
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* Initialize a fail-point. The name is formed in printf-like fashion
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* from "fmt" and the subsequent arguments.
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* Pair with fail_point_destroy().
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*/
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void fail_point_init(struct fail_point *, const char *fmt, ...)
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__printflike(2, 3);
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/**
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* Set the sleep function for a fail point
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* If sleep_fn is specified, then FAIL_POINT_SLEEP will result in a
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* (*fp->sleep_fn)(fp->sleep_arg) call by the timer thread. Otherwise,
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* if sleep_fn is NULL (default), then FAIL_POINT_SLEEP will result in the
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* fail_point_eval() call sleeping.
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*/
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static __inline void
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fail_point_sleep_set_func(struct fail_point *fp, void (*sleep_fn)(void *))
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{
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fp->fp_sleep_fn = sleep_fn;
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}
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/**
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* Set the argument for the sleep function for a fail point
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*/
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static __inline void
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fail_point_sleep_set_arg(struct fail_point *fp, void *sleep_arg)
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{
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fp->fp_sleep_arg = sleep_arg;
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}
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/**
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* Free the resources used by a fail-point. Pair with fail_point_init().
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*/
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void fail_point_destroy(struct fail_point *);
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/**
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* Evaluate a failpoint.
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*/
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static __inline enum fail_point_return_code
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fail_point_eval(struct fail_point *fp, int *ret)
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{
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if (TAILQ_EMPTY(&fp->fp_entries)) {
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return (FAIL_POINT_RC_CONTINUE);
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}
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return (fail_point_eval_nontrivial(fp, ret));
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}
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/* Declare a fail_point and its sysctl in a function. */
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#define _FAIL_POINT_NAME(name) _fail_point_##name
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#define _STRINGIFY_HELPER(x) #x
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#define _STRINGIFY(x) _STRINGIFY_HELPER(x)
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#define _FAIL_POINT_LOCATION() __FILE__ ":" _STRINGIFY(__LINE__)
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/**
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* Instantiate a failpoint which returns "value" from the function when triggered.
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* @param parent The parent sysctl under which to locate the sysctl
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* @param name The name of the failpoint in the sysctl tree (and printouts)
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* @return Instantly returns the return("value") specified in the
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* failpoint, if triggered.
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*/
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#define KFAIL_POINT_RETURN(parent, name) \
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KFAIL_POINT_CODE(parent, name, return RETURN_VALUE)
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/**
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* Instantiate a failpoint which returns (void) from the function when triggered.
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* @param parent The parent sysctl under which to locate the sysctl
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* @param name The name of the failpoint in the sysctl tree (and printouts)
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* @return Instantly returns void, if triggered in the failpoint.
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*/
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#define KFAIL_POINT_RETURN_VOID(parent, name) \
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KFAIL_POINT_CODE(parent, name, return)
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/**
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* Instantiate a failpoint which sets an error when triggered.
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* @param parent The parent sysctl under which to locate the sysctl
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* @param name The name of the failpoint in the sysctl tree (and printouts)
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* @param error_var A variable to set to the failpoint's specified
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* return-value when triggered
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*/
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#define KFAIL_POINT_ERROR(parent, name, error_var) \
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KFAIL_POINT_CODE(parent, name, (error_var) = RETURN_VALUE)
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/**
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* Instantiate a failpoint which sets an error and then goes to a
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* specified label in the function when triggered.
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* @param parent The parent sysctl under which to locate the sysctl
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* @param name The name of the failpoint in the sysctl tree (and printouts)
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* @param error_var A variable to set to the failpoint's specified
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* return-value when triggered
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* @param label The location to goto when triggered.
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*/
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#define KFAIL_POINT_GOTO(parent, name, error_var, label) \
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KFAIL_POINT_CODE(parent, name, (error_var) = RETURN_VALUE; goto label)
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/**
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* Instantiate a failpoint which runs arbitrary code when triggered.
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* @param parent The parent sysctl under which to locate the sysctl
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* @param name The name of the failpoint in the sysctl tree (and printouts)
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* @param code The arbitrary code to run when triggered. Can reference
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* "RETURN_VALUE" if desired to extract the specified user
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* return-value when triggered
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*/
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#define KFAIL_POINT_CODE(parent, name, code) \
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KFAIL_POINT_START(parent, name) { \
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code; \
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} FAIL_POINT_END
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/**
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* @}
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* (end group failpoint)
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*/
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/**
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* Internal macro to implement above #defines -- should not be used directly.
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* @ingroup failpoint_private
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*/
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#define KFAIL_POINT_START(parent, name) \
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do { \
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int RETURN_VALUE; \
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static struct fail_point _FAIL_POINT_NAME(name) = { \
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#name, \
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_FAIL_POINT_LOCATION(), \
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TAILQ_HEAD_INITIALIZER( \
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_FAIL_POINT_NAME(name).fp_entries), \
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0, \
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NULL, NULL, \
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}; \
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SYSCTL_OID(parent, OID_AUTO, name, \
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CTLTYPE_STRING | CTLFLAG_RW, \
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&_FAIL_POINT_NAME(name), 0, fail_point_sysctl, \
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"A", ""); \
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\
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if (__predict_false( \
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fail_point_eval(&_FAIL_POINT_NAME(name), \
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&RETURN_VALUE))) {
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/**
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* Internal macro to implement above #defines -- should not be used directly.
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* @ingroup failpoint_private
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*/
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#define FAIL_POINT_END \
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} \
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} while (0)
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#ifdef _KERNEL
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int fail_point_sysctl(SYSCTL_HANDLER_ARGS);
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/* The fail point sysctl tree. */
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SYSCTL_DECL(_debug_fail_point);
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#endif
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#define DEBUG_FP _debug_fail_point
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#endif /* _SYS_FAIL_H_ */
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