xref: /freebsd/sys/sys/fail.h (revision 95ee2897)
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  */
50 enum 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 
56 struct fail_point_entry;
57 struct 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  */
65 struct 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. */
102 enum 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  */
114 void 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 */
118 bool 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  */
125 static inline void
fail_point_sleep_set_pre_func(struct fail_point * fp,void (* sleep_fn)(void *))126 fail_point_sleep_set_pre_func(struct fail_point *fp, void (*sleep_fn)(void *))
127 {
128 	fp->fp_pre_sleep_fn = sleep_fn;
129 }
130 
131 static inline void
fail_point_sleep_set_pre_arg(struct fail_point * fp,void * sleep_arg)132 fail_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  */
141 static inline void
fail_point_sleep_set_post_func(struct fail_point * fp,void (* sleep_fn)(void *))142 fail_point_sleep_set_post_func(struct fail_point *fp, void (*sleep_fn)(void *))
143 {
144 	fp->fp_post_sleep_fn = sleep_fn;
145 }
146 
147 static inline void
fail_point_sleep_set_post_arg(struct fail_point * fp,void * sleep_arg)148 fail_point_sleep_set_post_arg(struct fail_point *fp, void *sleep_arg)
149 {
150 	fp->fp_post_sleep_arg = sleep_arg;
151 }
152 
153 void 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  */
161 static inline void
fail_point_use_timeout_path(struct fail_point * fp,bool use_timeout,void (* post_sleep_fn)(void *))162 fail_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  */
182 void fail_point_destroy(struct fail_point *);
183 
184 /**
185  * Evaluate a failpoint.
186  */
187 static inline enum fail_point_return_code
fail_point_eval(struct fail_point * fp,int * ret)188 fail_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
364 int fail_point_sysctl(SYSCTL_HANDLER_ARGS);
365 int fail_point_sysctl_status(SYSCTL_HANDLER_ARGS);
366 
367 /* The fail point sysctl tree. */
368 SYSCTL_DECL(_debug_fail_point);
369 #define	DEBUG_FP	_debug_fail_point
370 #endif
371 
372 #endif /* _SYS_FAIL_H_ */
373