1146 lines
29 KiB
C
1146 lines
29 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause
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*
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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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/**
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* @file
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*
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* fail(9) Facility.
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*
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* @ingroup failpoint_private
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*/
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/**
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* @defgroup failpoint fail(9) Facility
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*
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* Failpoints allow for injecting fake errors into running code on the fly,
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* without modifying code or recompiling with flags. Failpoints are always
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* present, and are very efficient when disabled. Failpoints are described
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* in man fail(9).
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*/
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/**
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* @defgroup failpoint_private Private fail(9) Implementation functions
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*
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* Private implementations for the actual failpoint code.
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*
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* @ingroup failpoint
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*/
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/**
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* @addtogroup failpoint_private
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* @{
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*/
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#include <sys/cdefs.h>
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#include "opt_stack.h"
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#include <sys/ctype.h>
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#include <sys/errno.h>
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#include <sys/fail.h>
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#include <sys/kernel.h>
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#include <sys/libkern.h>
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#include <sys/limits.h>
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#include <sys/lock.h>
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#include <sys/malloc.h>
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#include <sys/mutex.h>
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#include <sys/proc.h>
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#include <sys/sbuf.h>
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#include <sys/sleepqueue.h>
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#include <sys/sx.h>
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#include <sys/sysctl.h>
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#include <sys/types.h>
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#include <machine/atomic.h>
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#include <machine/stdarg.h>
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#ifdef ILOG_DEFINE_FOR_FILE
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ILOG_DEFINE_FOR_FILE(L_ISI_FAIL_POINT, L_ILOG, fail_point);
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#endif
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static MALLOC_DEFINE(M_FAIL_POINT, "Fail Points", "fail points system");
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#define fp_free(ptr) free(ptr, M_FAIL_POINT)
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#define fp_malloc(size, flags) malloc((size), M_FAIL_POINT, (flags))
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#define fs_free(ptr) fp_free(ptr)
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#define fs_malloc() fp_malloc(sizeof(struct fail_point_setting), \
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M_WAITOK | M_ZERO)
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/**
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* These define the wchans that are used for sleeping, pausing respectively.
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* They are chosen arbitrarily but need to be distinct to the failpoint and
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* the sleep/pause distinction.
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*/
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#define FP_SLEEP_CHANNEL(fp) (void*)(fp)
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#define FP_PAUSE_CHANNEL(fp) __DEVOLATILE(void*, &fp->fp_setting)
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/**
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* Don't allow more than this many entries in a fail point set by sysctl.
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* The 99.99...% case is to have 1 entry. I can't imagine having this many
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* entries, so it should not limit us. Saves on re-mallocs while holding
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* a non-sleepable lock.
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*/
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#define FP_MAX_ENTRY_COUNT 20
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/* Used to drain sbufs to the sysctl output */
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int fail_sysctl_drain_func(void *, const char *, int);
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/* Head of tailq of struct fail_point_entry */
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TAILQ_HEAD(fail_point_entry_queue, fail_point_entry);
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/**
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* fp entries garbage list; outstanding entries are cleaned up in the
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* garbage collector
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*/
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STAILQ_HEAD(fail_point_setting_garbage, fail_point_setting);
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static struct fail_point_setting_garbage fp_setting_garbage =
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STAILQ_HEAD_INITIALIZER(fp_setting_garbage);
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static struct mtx mtx_garbage_list;
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MTX_SYSINIT(mtx_garbage_list, &mtx_garbage_list, "fail point garbage mtx",
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MTX_SPIN);
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static struct sx sx_fp_set;
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SX_SYSINIT(sx_fp_set, &sx_fp_set, "fail point set sx");
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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_PAUSE, /**< sleep until failpoint is set to off */
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FAIL_POINT_YIELD, /**< yield the cpu */
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FAIL_POINT_DELAY, /**< busy wait the cpu */
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FAIL_POINT_NUMTYPES,
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FAIL_POINT_INVALID = -1
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};
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static struct {
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const char *name;
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int nmlen;
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} fail_type_strings[] = {
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#define FP_TYPE_NM_LEN(s) { s, sizeof(s) - 1 }
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[FAIL_POINT_OFF] = FP_TYPE_NM_LEN("off"),
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[FAIL_POINT_PANIC] = FP_TYPE_NM_LEN("panic"),
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[FAIL_POINT_RETURN] = FP_TYPE_NM_LEN("return"),
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[FAIL_POINT_BREAK] = FP_TYPE_NM_LEN("break"),
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[FAIL_POINT_PRINT] = FP_TYPE_NM_LEN("print"),
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[FAIL_POINT_SLEEP] = FP_TYPE_NM_LEN("sleep"),
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[FAIL_POINT_PAUSE] = FP_TYPE_NM_LEN("pause"),
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[FAIL_POINT_YIELD] = FP_TYPE_NM_LEN("yield"),
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[FAIL_POINT_DELAY] = FP_TYPE_NM_LEN("delay"),
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};
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#define FE_COUNT_UNTRACKED (INT_MIN)
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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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volatile bool fe_stale;
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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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int32_t fe_count; /**< number of times to fire, -1 means infinite */
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pid_t fe_pid; /**< only fail for this process */
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struct fail_point *fe_parent; /**< backpointer to fp */
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TAILQ_ENTRY(fail_point_entry) fe_entries; /**< next entry ptr */
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};
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struct fail_point_setting {
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STAILQ_ENTRY(fail_point_setting) fs_garbage_link;
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struct fail_point_entry_queue fp_entry_queue;
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struct fail_point * fs_parent;
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struct mtx feq_mtx; /* Gives fail_point_pause something to do. */
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};
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/**
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* Defines stating the equivalent of probablilty one (100%)
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*/
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enum {
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PROB_MAX = 1000000, /* probability between zero and this number */
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PROB_DIGITS = 6 /* number of zero's in above number */
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};
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/* Get a ref on an fp's fp_setting */
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static inline struct fail_point_setting *fail_point_setting_get_ref(
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struct fail_point *fp);
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/* Release a ref on an fp_setting */
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static inline void fail_point_setting_release_ref(struct fail_point *fp);
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/* Allocate and initialize a struct fail_point_setting */
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static struct fail_point_setting *fail_point_setting_new(struct
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fail_point *);
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/* Free a struct fail_point_setting */
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static void fail_point_setting_destroy(struct fail_point_setting *fp_setting);
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/* Allocate and initialize a struct fail_point_entry */
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static struct fail_point_entry *fail_point_entry_new(struct
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fail_point_setting *);
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/* Free a struct fail_point_entry */
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static void fail_point_entry_destroy(struct fail_point_entry *fp_entry);
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/* Append fp setting to garbage list */
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static inline void fail_point_setting_garbage_append(
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struct fail_point_setting *fp_setting);
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/* Swap fp's setting with fp_setting_new */
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static inline struct fail_point_setting *
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fail_point_swap_settings(struct fail_point *fp,
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struct fail_point_setting *fp_setting_new);
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/* Free up any zero-ref setting in the garbage queue */
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static void fail_point_garbage_collect(void);
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/* If this fail point's setting are empty, then swap it out to NULL. */
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static inline void fail_point_eval_swap_out(struct fail_point *fp,
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struct fail_point_setting *fp_setting);
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bool
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fail_point_is_off(struct fail_point *fp)
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{
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bool return_val;
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struct fail_point_setting *fp_setting;
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struct fail_point_entry *ent;
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return_val = true;
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fp_setting = fail_point_setting_get_ref(fp);
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if (fp_setting != NULL) {
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TAILQ_FOREACH(ent, &fp_setting->fp_entry_queue,
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fe_entries) {
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if (!ent->fe_stale) {
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return_val = false;
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break;
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}
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}
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}
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fail_point_setting_release_ref(fp);
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return (return_val);
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}
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/* Allocate and initialize a struct fail_point_setting */
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static struct fail_point_setting *
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fail_point_setting_new(struct fail_point *fp)
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{
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struct fail_point_setting *fs_new;
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fs_new = fs_malloc();
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fs_new->fs_parent = fp;
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TAILQ_INIT(&fs_new->fp_entry_queue);
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mtx_init(&fs_new->feq_mtx, "fail point entries", NULL, MTX_SPIN);
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fail_point_setting_garbage_append(fs_new);
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return (fs_new);
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}
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/* Free a struct fail_point_setting */
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static void
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fail_point_setting_destroy(struct fail_point_setting *fp_setting)
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{
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struct fail_point_entry *ent;
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while (!TAILQ_EMPTY(&fp_setting->fp_entry_queue)) {
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ent = TAILQ_FIRST(&fp_setting->fp_entry_queue);
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TAILQ_REMOVE(&fp_setting->fp_entry_queue, ent, fe_entries);
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fail_point_entry_destroy(ent);
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}
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fs_free(fp_setting);
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}
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/* Allocate and initialize a struct fail_point_entry */
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static struct fail_point_entry *
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fail_point_entry_new(struct fail_point_setting *fp_setting)
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{
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struct fail_point_entry *fp_entry;
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fp_entry = fp_malloc(sizeof(struct fail_point_entry),
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M_WAITOK | M_ZERO);
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fp_entry->fe_parent = fp_setting->fs_parent;
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fp_entry->fe_prob = PROB_MAX;
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fp_entry->fe_pid = NO_PID;
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fp_entry->fe_count = FE_COUNT_UNTRACKED;
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TAILQ_INSERT_TAIL(&fp_setting->fp_entry_queue, fp_entry,
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fe_entries);
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return (fp_entry);
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}
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/* Free a struct fail_point_entry */
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static void
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fail_point_entry_destroy(struct fail_point_entry *fp_entry)
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{
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fp_free(fp_entry);
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}
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/* Get a ref on an fp's fp_setting */
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static inline struct fail_point_setting *
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fail_point_setting_get_ref(struct fail_point *fp)
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{
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struct fail_point_setting *fp_setting;
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/* Invariant: if we have a ref, our pointer to fp_setting is safe */
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atomic_add_acq_32(&fp->fp_ref_cnt, 1);
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fp_setting = fp->fp_setting;
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return (fp_setting);
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}
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/* Release a ref on an fp_setting */
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static inline void
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fail_point_setting_release_ref(struct fail_point *fp)
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{
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KASSERT(&fp->fp_ref_cnt > 0, ("Attempting to deref w/no refs"));
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atomic_subtract_rel_32(&fp->fp_ref_cnt, 1);
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}
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/* Append fp entries to fp garbage list */
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static inline void
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fail_point_setting_garbage_append(struct fail_point_setting *fp_setting)
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{
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mtx_lock_spin(&mtx_garbage_list);
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STAILQ_INSERT_TAIL(&fp_setting_garbage, fp_setting,
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fs_garbage_link);
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mtx_unlock_spin(&mtx_garbage_list);
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}
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/* Swap fp's entries with fp_setting_new */
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static struct fail_point_setting *
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fail_point_swap_settings(struct fail_point *fp,
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struct fail_point_setting *fp_setting_new)
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{
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struct fail_point_setting *fp_setting_old;
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fp_setting_old = fp->fp_setting;
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fp->fp_setting = fp_setting_new;
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return (fp_setting_old);
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}
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static inline void
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fail_point_eval_swap_out(struct fail_point *fp,
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struct fail_point_setting *fp_setting)
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{
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/* We may have already been swapped out and replaced; ignore. */
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if (fp->fp_setting == fp_setting)
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fail_point_swap_settings(fp, NULL);
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}
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/* Free up any zero-ref entries in the garbage queue */
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static void
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fail_point_garbage_collect(void)
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{
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struct fail_point_setting *fs_current, *fs_next;
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struct fail_point_setting_garbage fp_ents_free_list;
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/**
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* We will transfer the entries to free to fp_ents_free_list while holding
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* the spin mutex, then free it after we drop the lock. This avoids
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* triggering witness due to sleepable mutexes in the memory
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* allocator.
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*/
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STAILQ_INIT(&fp_ents_free_list);
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mtx_lock_spin(&mtx_garbage_list);
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STAILQ_FOREACH_SAFE(fs_current, &fp_setting_garbage, fs_garbage_link,
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fs_next) {
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if (fs_current->fs_parent->fp_setting != fs_current &&
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fs_current->fs_parent->fp_ref_cnt == 0) {
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STAILQ_REMOVE(&fp_setting_garbage, fs_current,
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fail_point_setting, fs_garbage_link);
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STAILQ_INSERT_HEAD(&fp_ents_free_list, fs_current,
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fs_garbage_link);
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}
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}
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mtx_unlock_spin(&mtx_garbage_list);
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STAILQ_FOREACH_SAFE(fs_current, &fp_ents_free_list, fs_garbage_link,
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fs_next)
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fail_point_setting_destroy(fs_current);
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}
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/* Drain out all refs from this fail point */
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static inline void
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fail_point_drain(struct fail_point *fp, int expected_ref)
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{
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struct fail_point_setting *entries;
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entries = fail_point_swap_settings(fp, NULL);
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/**
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* We have unpaused all threads; so we will wait no longer
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* than the time taken for the longest remaining sleep, or
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* the length of time of a long-running code block.
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*/
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while (fp->fp_ref_cnt > expected_ref) {
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wakeup(FP_PAUSE_CHANNEL(fp));
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tsleep(&fp, PWAIT, "fail_point_drain", hz / 100);
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}
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if (fp->fp_callout)
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callout_drain(fp->fp_callout);
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fail_point_swap_settings(fp, entries);
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}
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static inline void
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fail_point_pause(struct fail_point *fp, enum fail_point_return_code *pret,
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struct mtx *mtx_sleep)
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{
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if (fp->fp_pre_sleep_fn)
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fp->fp_pre_sleep_fn(fp->fp_pre_sleep_arg);
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msleep_spin(FP_PAUSE_CHANNEL(fp), mtx_sleep, "failpt", 0);
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if (fp->fp_post_sleep_fn)
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fp->fp_post_sleep_fn(fp->fp_post_sleep_arg);
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}
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static inline void
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fail_point_sleep(struct fail_point *fp, int msecs,
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enum fail_point_return_code *pret)
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{
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int timo;
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/* Convert from millisecs to ticks, rounding up */
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timo = howmany((int64_t)msecs * hz, 1000L);
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if (timo > 0) {
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if (!(fp->fp_flags & FAIL_POINT_USE_TIMEOUT_PATH)) {
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if (fp->fp_pre_sleep_fn)
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fp->fp_pre_sleep_fn(fp->fp_pre_sleep_arg);
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tsleep(FP_SLEEP_CHANNEL(fp), PWAIT, "failpt", timo);
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if (fp->fp_post_sleep_fn)
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fp->fp_post_sleep_fn(fp->fp_post_sleep_arg);
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} else {
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if (fp->fp_pre_sleep_fn)
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fp->fp_pre_sleep_fn(fp->fp_pre_sleep_arg);
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callout_reset(fp->fp_callout, timo,
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fp->fp_post_sleep_fn, fp->fp_post_sleep_arg);
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*pret = FAIL_POINT_RC_QUEUED;
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}
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}
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}
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static char *parse_fail_point(struct fail_point_setting *, char *);
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static char *parse_term(struct fail_point_setting *, char *);
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static char *parse_number(int *out_units, int *out_decimal, char *);
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static char *parse_type(struct fail_point_entry *, char *);
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/**
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* Initialize a fail_point. The name is formed in a printf-like fashion
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* from "fmt" and subsequent arguments. This function is generally used
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* for custom failpoints located at odd places in the sysctl tree, and is
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* not explicitly needed for standard in-line-declared failpoints.
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*
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* @ingroup failpoint
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*/
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void
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fail_point_init(struct fail_point *fp, const char *fmt, ...)
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{
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va_list ap;
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char *name;
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int n;
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fp->fp_setting = NULL;
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fp->fp_flags = 0;
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/* Figure out the size of the name. */
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va_start(ap, fmt);
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n = vsnprintf(NULL, 0, fmt, ap);
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va_end(ap);
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/* Allocate the name and fill it in. */
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name = fp_malloc(n + 1, M_WAITOK);
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if (name != NULL) {
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va_start(ap, fmt);
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|
vsnprintf(name, n + 1, fmt, ap);
|
|
va_end(ap);
|
|
}
|
|
fp->fp_name = name;
|
|
fp->fp_location = "";
|
|
fp->fp_flags |= FAIL_POINT_DYNAMIC_NAME;
|
|
fp->fp_pre_sleep_fn = NULL;
|
|
fp->fp_pre_sleep_arg = NULL;
|
|
fp->fp_post_sleep_fn = NULL;
|
|
fp->fp_post_sleep_arg = NULL;
|
|
}
|
|
|
|
void
|
|
fail_point_alloc_callout(struct fail_point *fp)
|
|
{
|
|
|
|
/**
|
|
* This assumes that calls to fail_point_use_timeout_path()
|
|
* will not race.
|
|
*/
|
|
if (fp->fp_callout != NULL)
|
|
return;
|
|
fp->fp_callout = fp_malloc(sizeof(*fp->fp_callout), M_WAITOK);
|
|
callout_init(fp->fp_callout, CALLOUT_MPSAFE);
|
|
}
|
|
|
|
/**
|
|
* Free the resources held by a fail_point, and wake any paused threads.
|
|
* Thou shalt not allow threads to hit this fail point after you enter this
|
|
* function, nor shall you call this multiple times for a given fp.
|
|
* @ingroup failpoint
|
|
*/
|
|
void
|
|
fail_point_destroy(struct fail_point *fp)
|
|
{
|
|
|
|
fail_point_drain(fp, 0);
|
|
|
|
if ((fp->fp_flags & FAIL_POINT_DYNAMIC_NAME) != 0) {
|
|
fp_free(__DECONST(void *, fp->fp_name));
|
|
fp->fp_name = NULL;
|
|
}
|
|
fp->fp_flags = 0;
|
|
if (fp->fp_callout) {
|
|
fp_free(fp->fp_callout);
|
|
fp->fp_callout = NULL;
|
|
}
|
|
|
|
sx_xlock(&sx_fp_set);
|
|
fail_point_garbage_collect();
|
|
sx_xunlock(&sx_fp_set);
|
|
}
|
|
|
|
/**
|
|
* This does the real work of evaluating a fail point. If the fail point tells
|
|
* us to return a value, this function returns 1 and fills in 'return_value'
|
|
* (return_value is allowed to be null). If the fail point tells us to panic,
|
|
* we never return. Otherwise we just return 0 after doing some work, which
|
|
* means "keep going".
|
|
*/
|
|
enum fail_point_return_code
|
|
fail_point_eval_nontrivial(struct fail_point *fp, int *return_value)
|
|
{
|
|
bool execute = false;
|
|
struct fail_point_entry *ent;
|
|
struct fail_point_setting *fp_setting;
|
|
enum fail_point_return_code ret;
|
|
int cont;
|
|
int count;
|
|
int msecs;
|
|
int usecs;
|
|
|
|
ret = FAIL_POINT_RC_CONTINUE;
|
|
cont = 0; /* don't continue by default */
|
|
|
|
fp_setting = fail_point_setting_get_ref(fp);
|
|
if (fp_setting == NULL)
|
|
goto abort;
|
|
|
|
TAILQ_FOREACH(ent, &fp_setting->fp_entry_queue, fe_entries) {
|
|
if (ent->fe_stale)
|
|
continue;
|
|
|
|
if (ent->fe_prob < PROB_MAX &&
|
|
ent->fe_prob < random() % PROB_MAX)
|
|
continue;
|
|
|
|
if (ent->fe_pid != NO_PID && ent->fe_pid != curproc->p_pid)
|
|
continue;
|
|
|
|
if (ent->fe_count != FE_COUNT_UNTRACKED) {
|
|
count = ent->fe_count;
|
|
while (count > 0) {
|
|
if (atomic_cmpset_32(&ent->fe_count, count, count - 1)) {
|
|
count--;
|
|
execute = true;
|
|
break;
|
|
}
|
|
count = ent->fe_count;
|
|
}
|
|
if (execute == false)
|
|
/* We lost the race; consider the entry stale and bail now */
|
|
continue;
|
|
if (count == 0)
|
|
ent->fe_stale = true;
|
|
}
|
|
|
|
switch (ent->fe_type) {
|
|
case FAIL_POINT_PANIC:
|
|
panic("fail point %s panicking", fp->fp_name);
|
|
/* NOTREACHED */
|
|
|
|
case FAIL_POINT_RETURN:
|
|
if (return_value != NULL)
|
|
*return_value = ent->fe_arg;
|
|
ret = FAIL_POINT_RC_RETURN;
|
|
break;
|
|
|
|
case FAIL_POINT_BREAK:
|
|
printf("fail point %s breaking to debugger\n",
|
|
fp->fp_name);
|
|
breakpoint();
|
|
break;
|
|
|
|
case FAIL_POINT_PRINT:
|
|
printf("fail point %s executing\n", fp->fp_name);
|
|
cont = ent->fe_arg;
|
|
break;
|
|
|
|
case FAIL_POINT_SLEEP:
|
|
msecs = ent->fe_arg;
|
|
if (msecs)
|
|
fail_point_sleep(fp, msecs, &ret);
|
|
break;
|
|
|
|
case FAIL_POINT_PAUSE:
|
|
/**
|
|
* Pausing is inherently strange with multiple
|
|
* entries given our design. That is because some
|
|
* entries could be unreachable, for instance in cases like:
|
|
* pause->return. We can never reach the return entry.
|
|
* The sysctl layer actually truncates all entries after
|
|
* a pause for this reason.
|
|
*/
|
|
mtx_lock_spin(&fp_setting->feq_mtx);
|
|
fail_point_pause(fp, &ret, &fp_setting->feq_mtx);
|
|
mtx_unlock_spin(&fp_setting->feq_mtx);
|
|
break;
|
|
|
|
case FAIL_POINT_YIELD:
|
|
kern_yield(PRI_UNCHANGED);
|
|
break;
|
|
|
|
case FAIL_POINT_DELAY:
|
|
usecs = ent->fe_arg;
|
|
DELAY(usecs);
|
|
break;
|
|
|
|
default:
|
|
break;
|
|
}
|
|
|
|
if (cont == 0)
|
|
break;
|
|
}
|
|
|
|
if (fail_point_is_off(fp))
|
|
fail_point_eval_swap_out(fp, fp_setting);
|
|
|
|
abort:
|
|
fail_point_setting_release_ref(fp);
|
|
|
|
return (ret);
|
|
}
|
|
|
|
/**
|
|
* Translate internal fail_point structure into human-readable text.
|
|
*/
|
|
static void
|
|
fail_point_get(struct fail_point *fp, struct sbuf *sb,
|
|
bool verbose)
|
|
{
|
|
struct fail_point_entry *ent;
|
|
struct fail_point_setting *fp_setting;
|
|
struct fail_point_entry *fp_entry_cpy;
|
|
int cnt_sleeping;
|
|
int idx;
|
|
int printed_entry_count;
|
|
|
|
cnt_sleeping = 0;
|
|
idx = 0;
|
|
printed_entry_count = 0;
|
|
|
|
fp_entry_cpy = fp_malloc(sizeof(struct fail_point_entry) *
|
|
(FP_MAX_ENTRY_COUNT + 1), M_WAITOK);
|
|
|
|
fp_setting = fail_point_setting_get_ref(fp);
|
|
|
|
if (fp_setting != NULL) {
|
|
TAILQ_FOREACH(ent, &fp_setting->fp_entry_queue, fe_entries) {
|
|
if (ent->fe_stale)
|
|
continue;
|
|
|
|
KASSERT(printed_entry_count < FP_MAX_ENTRY_COUNT,
|
|
("FP entry list larger than allowed"));
|
|
|
|
fp_entry_cpy[printed_entry_count] = *ent;
|
|
++printed_entry_count;
|
|
}
|
|
}
|
|
fail_point_setting_release_ref(fp);
|
|
|
|
/* This is our equivalent of a NULL terminator */
|
|
fp_entry_cpy[printed_entry_count].fe_type = FAIL_POINT_INVALID;
|
|
|
|
while (idx < printed_entry_count) {
|
|
ent = &fp_entry_cpy[idx];
|
|
++idx;
|
|
if (ent->fe_prob < PROB_MAX) {
|
|
int decimal = ent->fe_prob % (PROB_MAX / 100);
|
|
int units = ent->fe_prob / (PROB_MAX / 100);
|
|
sbuf_printf(sb, "%d", units);
|
|
if (decimal) {
|
|
int digits = PROB_DIGITS - 2;
|
|
while (!(decimal % 10)) {
|
|
digits--;
|
|
decimal /= 10;
|
|
}
|
|
sbuf_printf(sb, ".%0*d", digits, decimal);
|
|
}
|
|
sbuf_printf(sb, "%%");
|
|
}
|
|
if (ent->fe_count >= 0)
|
|
sbuf_printf(sb, "%d*", ent->fe_count);
|
|
sbuf_printf(sb, "%s", fail_type_strings[ent->fe_type].name);
|
|
if (ent->fe_arg)
|
|
sbuf_printf(sb, "(%d)", ent->fe_arg);
|
|
if (ent->fe_pid != NO_PID)
|
|
sbuf_printf(sb, "[pid %d]", ent->fe_pid);
|
|
if (TAILQ_NEXT(ent, fe_entries))
|
|
sbuf_printf(sb, "->");
|
|
}
|
|
if (!printed_entry_count)
|
|
sbuf_printf(sb, "off");
|
|
|
|
fp_free(fp_entry_cpy);
|
|
if (verbose) {
|
|
#ifdef STACK
|
|
/* Print number of sleeping threads. queue=0 is the argument
|
|
* used by msleep when sending our threads to sleep. */
|
|
sbuf_printf(sb, "\nsleeping_thread_stacks = {\n");
|
|
sleepq_sbuf_print_stacks(sb, FP_SLEEP_CHANNEL(fp), 0,
|
|
&cnt_sleeping);
|
|
|
|
sbuf_printf(sb, "},\n");
|
|
#endif
|
|
sbuf_printf(sb, "sleeping_thread_count = %d,\n",
|
|
cnt_sleeping);
|
|
|
|
#ifdef STACK
|
|
sbuf_printf(sb, "paused_thread_stacks = {\n");
|
|
sleepq_sbuf_print_stacks(sb, FP_PAUSE_CHANNEL(fp), 0,
|
|
&cnt_sleeping);
|
|
|
|
sbuf_printf(sb, "},\n");
|
|
#endif
|
|
sbuf_printf(sb, "paused_thread_count = %d\n",
|
|
cnt_sleeping);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Set an internal fail_point structure from a human-readable failpoint string
|
|
* in a lock-safe manner.
|
|
*/
|
|
static int
|
|
fail_point_set(struct fail_point *fp, char *buf)
|
|
{
|
|
struct fail_point_entry *ent, *ent_next;
|
|
struct fail_point_setting *entries;
|
|
bool should_wake_paused;
|
|
bool should_truncate;
|
|
int error;
|
|
|
|
error = 0;
|
|
should_wake_paused = false;
|
|
should_truncate = false;
|
|
|
|
/* Parse new entries. */
|
|
/**
|
|
* ref protects our new malloc'd stuff from being garbage collected
|
|
* before we link it.
|
|
*/
|
|
fail_point_setting_get_ref(fp);
|
|
entries = fail_point_setting_new(fp);
|
|
if (parse_fail_point(entries, buf) == NULL) {
|
|
STAILQ_REMOVE(&fp_setting_garbage, entries,
|
|
fail_point_setting, fs_garbage_link);
|
|
fail_point_setting_destroy(entries);
|
|
error = EINVAL;
|
|
goto end;
|
|
}
|
|
|
|
/**
|
|
* Transfer the entries we are going to keep to a new list.
|
|
* Get rid of useless zero probability entries, and entries with hit
|
|
* count 0.
|
|
* If 'off' is present, and it has no hit count set, then all entries
|
|
* after it are discarded since they are unreachable.
|
|
*/
|
|
TAILQ_FOREACH_SAFE(ent, &entries->fp_entry_queue, fe_entries, ent_next) {
|
|
if (ent->fe_prob == 0 || ent->fe_count == 0) {
|
|
printf("Discarding entry which cannot execute %s\n",
|
|
fail_type_strings[ent->fe_type].name);
|
|
TAILQ_REMOVE(&entries->fp_entry_queue, ent,
|
|
fe_entries);
|
|
fp_free(ent);
|
|
continue;
|
|
} else if (should_truncate) {
|
|
printf("Discarding unreachable entry %s\n",
|
|
fail_type_strings[ent->fe_type].name);
|
|
TAILQ_REMOVE(&entries->fp_entry_queue, ent,
|
|
fe_entries);
|
|
fp_free(ent);
|
|
continue;
|
|
}
|
|
|
|
if (ent->fe_type == FAIL_POINT_OFF) {
|
|
should_wake_paused = true;
|
|
if (ent->fe_count == FE_COUNT_UNTRACKED) {
|
|
should_truncate = true;
|
|
TAILQ_REMOVE(&entries->fp_entry_queue, ent,
|
|
fe_entries);
|
|
fp_free(ent);
|
|
}
|
|
} else if (ent->fe_type == FAIL_POINT_PAUSE) {
|
|
should_truncate = true;
|
|
} else if (ent->fe_type == FAIL_POINT_SLEEP && (fp->fp_flags &
|
|
FAIL_POINT_NONSLEEPABLE)) {
|
|
/**
|
|
* If this fail point is annotated as being in a
|
|
* non-sleepable ctx, convert sleep to delay and
|
|
* convert the msec argument to usecs.
|
|
*/
|
|
printf("Sleep call request on fail point in "
|
|
"non-sleepable context; using delay instead "
|
|
"of sleep\n");
|
|
ent->fe_type = FAIL_POINT_DELAY;
|
|
ent->fe_arg *= 1000;
|
|
}
|
|
}
|
|
|
|
if (TAILQ_EMPTY(&entries->fp_entry_queue)) {
|
|
entries = fail_point_swap_settings(fp, NULL);
|
|
if (entries != NULL)
|
|
wakeup(FP_PAUSE_CHANNEL(fp));
|
|
} else {
|
|
if (should_wake_paused)
|
|
wakeup(FP_PAUSE_CHANNEL(fp));
|
|
fail_point_swap_settings(fp, entries);
|
|
}
|
|
|
|
end:
|
|
#ifdef IWARNING
|
|
if (error)
|
|
IWARNING("Failed to set %s %s to %s",
|
|
fp->fp_name, fp->fp_location, buf);
|
|
else
|
|
INOTICE("Set %s %s to %s",
|
|
fp->fp_name, fp->fp_location, buf);
|
|
#endif /* IWARNING */
|
|
|
|
fail_point_setting_release_ref(fp);
|
|
return (error);
|
|
}
|
|
|
|
#define MAX_FAIL_POINT_BUF 1023
|
|
|
|
/**
|
|
* Handle kernel failpoint set/get.
|
|
*/
|
|
int
|
|
fail_point_sysctl(SYSCTL_HANDLER_ARGS)
|
|
{
|
|
struct fail_point *fp;
|
|
char *buf;
|
|
struct sbuf sb, *sb_check;
|
|
int error;
|
|
|
|
buf = NULL;
|
|
error = 0;
|
|
fp = arg1;
|
|
|
|
sb_check = sbuf_new(&sb, NULL, 1024, SBUF_AUTOEXTEND);
|
|
if (sb_check != &sb)
|
|
return (ENOMEM);
|
|
|
|
sbuf_set_drain(&sb, (sbuf_drain_func *)fail_sysctl_drain_func, req);
|
|
|
|
/* Setting */
|
|
/**
|
|
* Lock protects any new entries from being garbage collected before we
|
|
* can link them to the fail point.
|
|
*/
|
|
sx_xlock(&sx_fp_set);
|
|
if (req->newptr) {
|
|
if (req->newlen > MAX_FAIL_POINT_BUF) {
|
|
error = EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
buf = fp_malloc(req->newlen + 1, M_WAITOK);
|
|
|
|
error = SYSCTL_IN(req, buf, req->newlen);
|
|
if (error)
|
|
goto out;
|
|
buf[req->newlen] = '\0';
|
|
|
|
error = fail_point_set(fp, buf);
|
|
}
|
|
|
|
fail_point_garbage_collect();
|
|
sx_xunlock(&sx_fp_set);
|
|
|
|
/* Retrieving. */
|
|
fail_point_get(fp, &sb, false);
|
|
|
|
out:
|
|
sbuf_finish(&sb);
|
|
sbuf_delete(&sb);
|
|
|
|
if (buf)
|
|
fp_free(buf);
|
|
|
|
return (error);
|
|
}
|
|
|
|
int
|
|
fail_point_sysctl_status(SYSCTL_HANDLER_ARGS)
|
|
{
|
|
struct fail_point *fp;
|
|
struct sbuf sb, *sb_check;
|
|
|
|
fp = arg1;
|
|
|
|
sb_check = sbuf_new(&sb, NULL, 1024, SBUF_AUTOEXTEND);
|
|
if (sb_check != &sb)
|
|
return (ENOMEM);
|
|
|
|
sbuf_set_drain(&sb, (sbuf_drain_func *)fail_sysctl_drain_func, req);
|
|
|
|
/* Retrieving. */
|
|
fail_point_get(fp, &sb, true);
|
|
|
|
sbuf_finish(&sb);
|
|
sbuf_delete(&sb);
|
|
|
|
/**
|
|
* Lock protects any new entries from being garbage collected before we
|
|
* can link them to the fail point.
|
|
*/
|
|
sx_xlock(&sx_fp_set);
|
|
fail_point_garbage_collect();
|
|
sx_xunlock(&sx_fp_set);
|
|
|
|
return (0);
|
|
}
|
|
|
|
int
|
|
fail_sysctl_drain_func(void *sysctl_args, const char *buf, int len)
|
|
{
|
|
struct sysctl_req *sa;
|
|
int error;
|
|
|
|
sa = sysctl_args;
|
|
|
|
error = SYSCTL_OUT(sa, buf, len);
|
|
|
|
if (error == ENOMEM)
|
|
return (-1);
|
|
else
|
|
return (len);
|
|
}
|
|
|
|
/**
|
|
* Internal helper function to translate a human-readable failpoint string
|
|
* into a internally-parsable fail_point structure.
|
|
*/
|
|
static char *
|
|
parse_fail_point(struct fail_point_setting *ents, char *p)
|
|
{
|
|
/* <fail_point> ::
|
|
* <term> ( "->" <term> )*
|
|
*/
|
|
uint8_t term_count;
|
|
|
|
term_count = 1;
|
|
|
|
p = parse_term(ents, p);
|
|
if (p == NULL)
|
|
return (NULL);
|
|
|
|
while (*p != '\0') {
|
|
term_count++;
|
|
if (p[0] != '-' || p[1] != '>' ||
|
|
(p = parse_term(ents, p+2)) == NULL ||
|
|
term_count > FP_MAX_ENTRY_COUNT)
|
|
return (NULL);
|
|
}
|
|
return (p);
|
|
}
|
|
|
|
/**
|
|
* Internal helper function to parse an individual term from a failpoint.
|
|
*/
|
|
static char *
|
|
parse_term(struct fail_point_setting *ents, char *p)
|
|
{
|
|
struct fail_point_entry *ent;
|
|
|
|
ent = fail_point_entry_new(ents);
|
|
|
|
/*
|
|
* <term> ::
|
|
* ( (<float> "%") | (<integer> "*" ) )*
|
|
* <type>
|
|
* [ "(" <integer> ")" ]
|
|
* [ "[pid " <integer> "]" ]
|
|
*/
|
|
|
|
/* ( (<float> "%") | (<integer> "*" ) )* */
|
|
while (isdigit(*p) || *p == '.') {
|
|
int units, decimal;
|
|
|
|
p = parse_number(&units, &decimal, p);
|
|
if (p == NULL)
|
|
return (NULL);
|
|
|
|
if (*p == '%') {
|
|
if (units > 100) /* prevent overflow early */
|
|
units = 100;
|
|
ent->fe_prob = units * (PROB_MAX / 100) + decimal;
|
|
if (ent->fe_prob > PROB_MAX)
|
|
ent->fe_prob = PROB_MAX;
|
|
} else if (*p == '*') {
|
|
if (!units || units < 0 || decimal)
|
|
return (NULL);
|
|
ent->fe_count = units;
|
|
} else
|
|
return (NULL);
|
|
p++;
|
|
}
|
|
|
|
/* <type> */
|
|
p = parse_type(ent, p);
|
|
if (p == NULL)
|
|
return (NULL);
|
|
if (*p == '\0')
|
|
return (p);
|
|
|
|
/* [ "(" <integer> ")" ] */
|
|
if (*p != '(')
|
|
return (p);
|
|
p++;
|
|
if (!isdigit(*p) && *p != '-')
|
|
return (NULL);
|
|
ent->fe_arg = strtol(p, &p, 0);
|
|
if (*p++ != ')')
|
|
return (NULL);
|
|
|
|
/* [ "[pid " <integer> "]" ] */
|
|
#define PID_STRING "[pid "
|
|
if (strncmp(p, PID_STRING, sizeof(PID_STRING) - 1) != 0)
|
|
return (p);
|
|
p += sizeof(PID_STRING) - 1;
|
|
if (!isdigit(*p))
|
|
return (NULL);
|
|
ent->fe_pid = strtol(p, &p, 0);
|
|
if (*p++ != ']')
|
|
return (NULL);
|
|
|
|
return (p);
|
|
}
|
|
|
|
/**
|
|
* Internal helper function to parse a numeric for a failpoint term.
|
|
*/
|
|
static char *
|
|
parse_number(int *out_units, int *out_decimal, char *p)
|
|
{
|
|
char *old_p;
|
|
|
|
/**
|
|
* <number> ::
|
|
* <integer> [ "." <integer> ] |
|
|
* "." <integer>
|
|
*/
|
|
|
|
/* whole part */
|
|
old_p = p;
|
|
*out_units = strtol(p, &p, 10);
|
|
if (p == old_p && *p != '.')
|
|
return (NULL);
|
|
|
|
/* fractional part */
|
|
*out_decimal = 0;
|
|
if (*p == '.') {
|
|
int digits = 0;
|
|
p++;
|
|
while (isdigit(*p)) {
|
|
int digit = *p - '0';
|
|
if (digits < PROB_DIGITS - 2)
|
|
*out_decimal = *out_decimal * 10 + digit;
|
|
else if (digits == PROB_DIGITS - 2 && digit >= 5)
|
|
(*out_decimal)++;
|
|
digits++;
|
|
p++;
|
|
}
|
|
if (!digits) /* need at least one digit after '.' */
|
|
return (NULL);
|
|
while (digits++ < PROB_DIGITS - 2) /* add implicit zeros */
|
|
*out_decimal *= 10;
|
|
}
|
|
|
|
return (p); /* success */
|
|
}
|
|
|
|
/**
|
|
* Internal helper function to parse an individual type for a failpoint term.
|
|
*/
|
|
static char *
|
|
parse_type(struct fail_point_entry *ent, char *beg)
|
|
{
|
|
enum fail_point_t type;
|
|
int len;
|
|
|
|
for (type = FAIL_POINT_OFF; type < FAIL_POINT_NUMTYPES; type++) {
|
|
len = fail_type_strings[type].nmlen;
|
|
if (strncmp(fail_type_strings[type].name, beg, len) == 0) {
|
|
ent->fe_type = type;
|
|
return (beg + len);
|
|
}
|
|
}
|
|
return (NULL);
|
|
}
|
|
|
|
/* The fail point sysctl tree. */
|
|
SYSCTL_NODE(_debug, OID_AUTO, fail_point, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
|
|
"fail points");
|
|
|
|
/* Debugging/testing stuff for fail point */
|
|
static int
|
|
sysctl_test_fail_point(SYSCTL_HANDLER_ARGS)
|
|
{
|
|
|
|
KFAIL_POINT_RETURN(DEBUG_FP, test_fail_point);
|
|
return (0);
|
|
}
|
|
SYSCTL_OID(_debug_fail_point, OID_AUTO, test_trigger_fail_point,
|
|
CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_NEEDGIANT, NULL, 0,
|
|
sysctl_test_fail_point, "A",
|
|
"Trigger test fail points");
|