1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2009-2019 Dell EMC Isilon http://www.isilon.com/
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27/**
28 * @file
29 *
30 * Main header for failpoint facility.
31 */
32#ifndef _SYS_FAIL_H_
33#define _SYS_FAIL_H_
34
35#include <sys/param.h>
36#include <sys/cdefs.h>
37#include <sys/linker_set.h>
38#include <sys/queue.h>
39#include <sys/sysctl.h>
40#include <sys/condvar.h>
41#include <sys/kernel.h>
42#include <sys/lock.h>
43#include <sys/mutex.h>
44#include <sys/systm.h>
45
46/**
47 * Failpoint return codes, used internally.
48 * @ingroup failpoint_private
49 */
50enum fail_point_return_code {
51 FAIL_POINT_RC_CONTINUE = 0, /**< Continue with normal execution */
52 FAIL_POINT_RC_RETURN, /**< FP evaluated to 'return' */
53 FAIL_POINT_RC_QUEUED, /**< sleep_fn will be called */
54};
55
56struct fail_point_entry;
57struct fail_point_setting;
58
59/**
60 * Internal failpoint structure, tracking all the current details of the
61 * failpoint. This structure is the core component shared between the
62 * failure-injection code and the user-interface.
63 * @ingroup failpoint_private
64 */
65struct fail_point {
66 const char *fp_name; /* name of fail point */
67 const char *fp_location; /* file:line of fail point */
68 volatile int fp_ref_cnt; /**
69 * protects fp_setting: while holding
70 * a ref, fp_setting points to an
71 * unfreed fail_point_setting
72 */
73 struct fail_point_setting * volatile fp_setting;
74 int fp_flags;
75
76 /**< Function to call before sleep or pause */
77 void (*fp_pre_sleep_fn)(void *);
78 /**< Arg for fp_pre_sleep_fn */
79 void *fp_pre_sleep_arg;
80
81 /**< Function to call after waking from sleep or pause */
82 void (*fp_post_sleep_fn)(void *);
83 /**< Arg for fp_post_sleep_fn */
84 void *fp_post_sleep_arg;
85
86 struct callout *fp_callout;
87};
88
89#define FAIL_POINT_DYNAMIC_NAME 0x01 /**< Must free name on destroy */
90/**< Use timeout path for sleep instead of msleep */
91#define FAIL_POINT_USE_TIMEOUT_PATH 0x02
92/**< If fail point is set to sleep, replace the sleep call with delay */
93#define FAIL_POINT_NONSLEEPABLE 0x04
94
95#define FAIL_POINT_CV_DESC "fp cv no iterators"
96#define FAIL_POINT_IS_OFF(fp) (__predict_true((fp)->fp_setting == NULL) || \
97 __predict_true(fail_point_is_off(fp)))
98
99__BEGIN_DECLS
100
101/* Private failpoint eval function -- use fail_point_eval() instead. */
102enum fail_point_return_code fail_point_eval_nontrivial(struct fail_point *,
103 int *ret);
104
105/**
106 * @addtogroup failpoint
107 * @{
108 */
109/*
110 * Initialize a fail-point. The name is formed in printf-like fashion
111 * from "fmt" and the subsequent arguments.
112 * Pair with fail_point_destroy().
113 */
114void fail_point_init(struct fail_point *, const char *fmt, ...)
115 __printflike(2, 3);
116
117/* Return true iff this fail point is set to off, false otherwise */
118bool fail_point_is_off(struct fail_point *fp);
119
120/**
121 * Set the pre-sleep function for a fail point
122 * If fp_post_sleep_fn is specified, then FAIL_POINT_SLEEP will result in a
123 * (*fp->fp_pre_sleep_fn)(fp->fp_pre_sleep_arg) call by the thread.
124 */
125static inline void
126fail_point_sleep_set_pre_func(struct fail_point *fp, void (*sleep_fn)(void *))
127{
128 fp->fp_pre_sleep_fn = sleep_fn;
129}
130
131static inline void
132fail_point_sleep_set_pre_arg(struct fail_point *fp, void *sleep_arg)
133{
134 fp->fp_pre_sleep_arg = sleep_arg;
135}
136
137/**
138 * Set the post-sleep function. This will be passed to timeout if we take
139 * the timeout path. This must be set if you sleep using the timeout path.
140 */
141static inline void
142fail_point_sleep_set_post_func(struct fail_point *fp, void (*sleep_fn)(void *))
143{
144 fp->fp_post_sleep_fn = sleep_fn;
145}
146
147static inline void
148fail_point_sleep_set_post_arg(struct fail_point *fp, void *sleep_arg)
149{
150 fp->fp_post_sleep_arg = sleep_arg;
151}
152
153void fail_point_alloc_callout(struct fail_point *);
154
155/**
156 * If the FAIL_POINT_USE_TIMEOUT flag is set on a failpoint, then
157 * FAIL_POINT_SLEEP will result in a call to callout_reset instead of
158 * msleep. Note that if you sleep while this flag is set, you must
159 * set fp_post_sleep_fn or an error will occur upon waking.
160 */
161static inline void
162fail_point_use_timeout_path(struct fail_point *fp, bool use_timeout,
163 void (*post_sleep_fn)(void *))
164{
165 KASSERT(!use_timeout || post_sleep_fn != NULL ||
166 (post_sleep_fn == NULL && fp->fp_post_sleep_fn != NULL),
167 ("Setting fp to use timeout, but not setting post_sleep_fn\n"));
168
169 if (use_timeout) {
170 fail_point_alloc_callout(fp);
171 fp->fp_flags |= FAIL_POINT_USE_TIMEOUT_PATH;
172 } else
173 fp->fp_flags &= ~FAIL_POINT_USE_TIMEOUT_PATH;
174
175 if (post_sleep_fn != NULL)
176 fp->fp_post_sleep_fn = post_sleep_fn;
177}
178
179/**
180 * Free the resources used by a fail-point. Pair with fail_point_init().
181 */
182void fail_point_destroy(struct fail_point *);
183
184/**
185 * Evaluate a failpoint.
186 */
187static inline enum fail_point_return_code
188fail_point_eval(struct fail_point *fp, int *ret)
189{
190 if (__predict_true(fp->fp_setting == NULL))
191 return (FAIL_POINT_RC_CONTINUE);
192 return (fail_point_eval_nontrivial(fp, ret));
193}
194
195__END_DECLS
196
197/* Declare a fail_point and its sysctl in a function. */
198#define KFAIL_POINT_DECLARE(name) \
199 extern struct fail_point _FAIL_POINT_NAME(name)
200#define _FAIL_POINT_NAME(name) _fail_point_##name
201#define _FAIL_POINT_LOCATION() "(" __FILE__ ":" __XSTRING(__LINE__) ")"
202#define KFAIL_POINT_DEFINE(parent, name, flags) \
203 struct fail_point _FAIL_POINT_NAME(name) = { \
204 .fp_name = #name, \
205 .fp_location = _FAIL_POINT_LOCATION(), \
206 .fp_ref_cnt = 0, \
207 .fp_setting = NULL, \
208 .fp_flags = (flags), \
209 .fp_pre_sleep_fn = NULL, \
210 .fp_pre_sleep_arg = NULL, \
211 .fp_post_sleep_fn = NULL, \
212 .fp_post_sleep_arg = NULL, \
213 }; \
214 SYSCTL_OID(parent, OID_AUTO, name, \
215 CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_MPSAFE, \
216 &_FAIL_POINT_NAME(name), 0, fail_point_sysctl, \
217 "A", ""); \
218 SYSCTL_OID(parent, OID_AUTO, status_##name, \
219 CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, \
220 &_FAIL_POINT_NAME(name), 0, \
221 fail_point_sysctl_status, "A", "");
222
223#define _FAIL_POINT_INIT(parent, name, flags) \
224 static KFAIL_POINT_DEFINE(parent, name, flags)
225#define _FAIL_POINT_EVAL(name, cond, code...) \
226 int RETURN_VALUE; \
227 \
228 if (__predict_false(cond && \
229 fail_point_eval(&_FAIL_POINT_NAME(name), &RETURN_VALUE))) { \
230 \
231 code; \
232 \
233 }
234#define KFAIL_POINT_EVAL(name, code...) \
235 _FAIL_POINT_EVAL(name, true, code)
236
237/**
238 * Instantiate a failpoint which returns "RETURN_VALUE" from the function
239 * when triggered.
240 * @param parent The parent sysctl under which to locate the fp's sysctl
241 * @param name The name of the failpoint in the sysctl tree (and printouts)
242 * @return Instantly returns the RETURN_VALUE specified in the
243 * failpoint, if triggered.
244 */
245#define KFAIL_POINT_RETURN(parent, name) \
246 KFAIL_POINT_CODE(parent, name, return RETURN_VALUE)
247
248/**
249 * Instantiate a failpoint which returns (void) from the function when
250 * triggered.
251 * @param parent The parent sysctl under which to locate the sysctl
252 * @param name The name of the failpoint in the sysctl tree (and printouts)
253 * @return Instantly returns void, if triggered in the failpoint.
254 */
255#define KFAIL_POINT_RETURN_VOID(parent, name) \
256 KFAIL_POINT_CODE(parent, name, return)
257
258/**
259 * Instantiate a failpoint which sets an error when triggered.
260 * @param parent The parent sysctl under which to locate the sysctl
261 * @param name The name of the failpoint in the sysctl tree (and
262 * printouts)
263 * @param error_var A variable to set to the failpoint's specified
264 * return-value when triggered
265 */
266#define KFAIL_POINT_ERROR(parent, name, error_var) \
267 KFAIL_POINT_CODE(parent, name, (error_var) = RETURN_VALUE)
268
269/**
270 * Instantiate a failpoint which sets an error and then goes to a
271 * specified label in the function when triggered.
272 * @param parent The parent sysctl under which to locate the sysctl
273 * @param name The name of the failpoint in the sysctl tree (and
274 * printouts)
275 * @param error_var A variable to set to the failpoint's specified
276 * return-value when triggered
277 * @param label The location to goto when triggered.
278 */
279#define KFAIL_POINT_GOTO(parent, name, error_var, label) \
280 KFAIL_POINT_CODE(parent, name, (error_var) = RETURN_VALUE; goto label)
281
282/**
283 * Instantiate a failpoint which sets its pre- and post-sleep callback
284 * mechanisms.
285 * @param parent The parent sysctl under which to locate the sysctl
286 * @param name The name of the failpoint in the sysctl tree (and
287 * printouts)
288 * @param pre_func Function pointer to the pre-sleep function, which will be
289 * called directly before going to sleep.
290 * @param pre_arg Argument to the pre-sleep function
291 * @param post_func Function pointer to the pot-sleep function, which will be
292 * called directly before going to sleep.
293 * @param post_arg Argument to the post-sleep function
294 */
295#define KFAIL_POINT_SLEEP_CALLBACKS(parent, name, pre_func, pre_arg, \
296 post_func, post_arg) \
297 KFAIL_POINT_CODE_SLEEP_CALLBACKS(parent, name, pre_func, \
298 pre_arg, post_func, post_arg, return RETURN_VALUE)
299
300/**
301 * Instantiate a failpoint which runs arbitrary code when triggered, and sets
302 * its pre- and post-sleep callback mechanisms
303 * @param parent The parent sysctl under which to locate the sysctl
304 * @param name The name of the failpoint in the sysctl tree (and
305 * printouts)
306 * @param pre_func Function pointer to the pre-sleep function, which will be
307 * called directly before going to sleep.
308 * @param pre_arg Argument to the pre-sleep function
309 * @param post_func Function pointer to the pot-sleep function, which will be
310 * called directly before going to sleep.
311 * @param post_arg Argument to the post-sleep function
312 * @param code The arbitrary code to run when triggered. Can reference
313 * "RETURN_VALUE" if desired to extract the specified
314 * user return-value when triggered. Note that this is
315 * implemented with a do-while loop so be careful of
316 * break and continue statements.
317 */
318#define KFAIL_POINT_CODE_SLEEP_CALLBACKS(parent, name, pre_func, pre_arg, \
319 post_func, post_arg, code...) \
320 do { \
321 _FAIL_POINT_INIT(parent, name) \
322 _FAIL_POINT_NAME(name).fp_pre_sleep_fn = pre_func; \
323 _FAIL_POINT_NAME(name).fp_pre_sleep_arg = pre_arg; \
324 _FAIL_POINT_NAME(name).fp_post_sleep_fn = post_func; \
325 _FAIL_POINT_NAME(name).fp_post_sleep_arg = post_arg; \
326 _FAIL_POINT_EVAL(name, true, code) \
327 } while (0)
328
329/**
330 * Instantiate a failpoint which runs arbitrary code when triggered.
331 * @param parent The parent sysctl under which to locate the sysctl
332 * @param name The name of the failpoint in the sysctl tree
333 * (and printouts)
334 * @param code The arbitrary code to run when triggered. Can reference
335 * "RETURN_VALUE" if desired to extract the specified
336 * user return-value when triggered. Note that this is
337 * implemented with a do-while loop so be careful of
338 * break and continue statements.
339 */
340#define KFAIL_POINT_CODE(parent, name, code...) \
341 do { \
342 _FAIL_POINT_INIT(parent, name, 0) \
343 _FAIL_POINT_EVAL(name, true, code) \
344 } while (0)
345
346#define KFAIL_POINT_CODE_FLAGS(parent, name, flags, code...) \
347 do { \
348 _FAIL_POINT_INIT(parent, name, flags) \
349 _FAIL_POINT_EVAL(name, true, code) \
350 } while (0)
351
352#define KFAIL_POINT_CODE_COND(parent, name, cond, flags, code...) \
353 do { \
354 _FAIL_POINT_INIT(parent, name, flags) \
355 _FAIL_POINT_EVAL(name, cond, code) \
356 } while (0)
357
358/**
359 * @}
360 * (end group failpoint)
361 */
362
363#ifdef _KERNEL
364int fail_point_sysctl(SYSCTL_HANDLER_ARGS);
365int fail_point_sysctl_status(SYSCTL_HANDLER_ARGS);
366
367/* The fail point sysctl tree. */
368SYSCTL_DECL(_debug_fail_point);
369#define DEBUG_FP _debug_fail_point
370#endif
371
372#endif /* _SYS_FAIL_H_ */