2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright (c) 2009-2019 Dell EMC Isilon http://www.isilon.com/
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32 * Main header for failpoint facility.
37 #include <sys/param.h>
38 #include <sys/cdefs.h>
39 #include <sys/linker_set.h>
40 #include <sys/queue.h>
41 #include <sys/sysctl.h>
42 #include <sys/condvar.h>
43 #include <sys/kernel.h>
45 #include <sys/mutex.h>
46 #include <sys/systm.h>
49 * Failpoint return codes, used internally.
50 * @ingroup failpoint_private
52 enum fail_point_return_code {
53 FAIL_POINT_RC_CONTINUE = 0, /**< Continue with normal execution */
54 FAIL_POINT_RC_RETURN, /**< FP evaluated to 'return' */
55 FAIL_POINT_RC_QUEUED, /**< sleep_fn will be called */
58 struct fail_point_entry;
59 struct fail_point_setting;
62 * Internal failpoint structure, tracking all the current details of the
63 * failpoint. This structure is the core component shared between the
64 * failure-injection code and the user-interface.
65 * @ingroup failpoint_private
68 const char *fp_name; /* name of fail point */
69 const char *fp_location; /* file:line of fail point */
70 volatile int fp_ref_cnt; /**
71 * protects fp_setting: while holding
72 * a ref, fp_setting points to an
73 * unfreed fail_point_setting
75 struct fail_point_setting * volatile fp_setting;
78 /**< Function to call before sleep or pause */
79 void (*fp_pre_sleep_fn)(void *);
80 /**< Arg for fp_pre_sleep_fn */
81 void *fp_pre_sleep_arg;
83 /**< Function to call after waking from sleep or pause */
84 void (*fp_post_sleep_fn)(void *);
85 /**< Arg for fp_post_sleep_fn */
86 void *fp_post_sleep_arg;
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
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)))
101 /* Private failpoint eval function -- use fail_point_eval() instead. */
102 enum fail_point_return_code fail_point_eval_nontrivial(struct fail_point *,
106 * @addtogroup failpoint
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().
114 void fail_point_init(struct fail_point *, const char *fmt, ...)
117 /* Return true iff this fail point is set to off, false otherwise */
118 bool fail_point_is_off(struct fail_point *fp);
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.
126 fail_point_sleep_set_pre_func(struct fail_point *fp, void (*sleep_fn)(void *))
128 fp->fp_pre_sleep_fn = sleep_fn;
132 fail_point_sleep_set_pre_arg(struct fail_point *fp, void *sleep_arg)
134 fp->fp_pre_sleep_arg = sleep_arg;
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.
142 fail_point_sleep_set_post_func(struct fail_point *fp, void (*sleep_fn)(void *))
144 fp->fp_post_sleep_fn = sleep_fn;
148 fail_point_sleep_set_post_arg(struct fail_point *fp, void *sleep_arg)
150 fp->fp_post_sleep_arg = sleep_arg;
153 * If the FAIL_POINT_USE_TIMEOUT flag is set on a failpoint, then
154 * FAIL_POINT_SLEEP will result in a call to timeout instead of
155 * msleep. Note that if you sleep while this flag is set, you must
156 * set fp_post_sleep_fn or an error will occur upon waking.
159 fail_point_use_timeout_path(struct fail_point *fp, bool use_timeout,
160 void (*post_sleep_fn)(void *))
162 KASSERT(!use_timeout || post_sleep_fn != NULL ||
163 (post_sleep_fn == NULL && fp->fp_post_sleep_fn != NULL),
164 ("Setting fp to use timeout, but not setting post_sleep_fn\n"));
167 fp->fp_flags |= FAIL_POINT_USE_TIMEOUT_PATH;
169 fp->fp_flags &= ~FAIL_POINT_USE_TIMEOUT_PATH;
171 if (post_sleep_fn != NULL)
172 fp->fp_post_sleep_fn = post_sleep_fn;
176 * Free the resources used by a fail-point. Pair with fail_point_init().
178 void fail_point_destroy(struct fail_point *);
181 * Evaluate a failpoint.
183 static inline enum fail_point_return_code
184 fail_point_eval(struct fail_point *fp, int *ret)
186 if (__predict_true(fp->fp_setting == NULL))
187 return (FAIL_POINT_RC_CONTINUE);
188 return (fail_point_eval_nontrivial(fp, ret));
193 /* Declare a fail_point and its sysctl in a function. */
194 #define KFAIL_POINT_DECLARE(name) \
195 extern struct fail_point _FAIL_POINT_NAME(name)
196 #define _FAIL_POINT_NAME(name) _fail_point_##name
197 #define _FAIL_POINT_LOCATION() "(" __FILE__ ":" __XSTRING(__LINE__) ")"
198 #define KFAIL_POINT_DEFINE(parent, name, flags) \
199 struct fail_point _FAIL_POINT_NAME(name) = { \
201 .fp_location = _FAIL_POINT_LOCATION(), \
203 .fp_setting = NULL, \
204 .fp_flags = (flags), \
205 .fp_pre_sleep_fn = NULL, \
206 .fp_pre_sleep_arg = NULL, \
207 .fp_post_sleep_fn = NULL, \
208 .fp_post_sleep_arg = NULL, \
210 SYSCTL_OID(parent, OID_AUTO, name, \
211 CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_MPSAFE, \
212 &_FAIL_POINT_NAME(name), 0, fail_point_sysctl, \
214 SYSCTL_OID(parent, OID_AUTO, status_##name, \
215 CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, \
216 &_FAIL_POINT_NAME(name), 0, \
217 fail_point_sysctl_status, "A", "");
219 #define _FAIL_POINT_INIT(parent, name, flags) \
220 static KFAIL_POINT_DEFINE(parent, name, flags)
221 #define _FAIL_POINT_EVAL(name, cond, code...) \
224 if (__predict_false(cond && \
225 fail_point_eval(&_FAIL_POINT_NAME(name), &RETURN_VALUE))) { \
230 #define KFAIL_POINT_EVAL(name, code...) \
231 _FAIL_POINT_EVAL(name, true, code)
234 * Instantiate a failpoint which returns "RETURN_VALUE" from the function
236 * @param parent The parent sysctl under which to locate the fp's sysctl
237 * @param name The name of the failpoint in the sysctl tree (and printouts)
238 * @return Instantly returns the RETURN_VALUE specified in the
239 * failpoint, if triggered.
241 #define KFAIL_POINT_RETURN(parent, name) \
242 KFAIL_POINT_CODE(parent, name, return RETURN_VALUE)
245 * Instantiate a failpoint which returns (void) from the function when
247 * @param parent The parent sysctl under which to locate the sysctl
248 * @param name The name of the failpoint in the sysctl tree (and printouts)
249 * @return Instantly returns void, if triggered in the failpoint.
251 #define KFAIL_POINT_RETURN_VOID(parent, name) \
252 KFAIL_POINT_CODE(parent, name, return)
255 * Instantiate a failpoint which sets an error when triggered.
256 * @param parent The parent sysctl under which to locate the sysctl
257 * @param name The name of the failpoint in the sysctl tree (and
259 * @param error_var A variable to set to the failpoint's specified
260 * return-value when triggered
262 #define KFAIL_POINT_ERROR(parent, name, error_var) \
263 KFAIL_POINT_CODE(parent, name, (error_var) = RETURN_VALUE)
266 * Instantiate a failpoint which sets an error and then goes to a
267 * specified label in the function when triggered.
268 * @param parent The parent sysctl under which to locate the sysctl
269 * @param name The name of the failpoint in the sysctl tree (and
271 * @param error_var A variable to set to the failpoint's specified
272 * return-value when triggered
273 * @param label The location to goto when triggered.
275 #define KFAIL_POINT_GOTO(parent, name, error_var, label) \
276 KFAIL_POINT_CODE(parent, name, (error_var) = RETURN_VALUE; goto label)
279 * Instantiate a failpoint which sets its pre- and post-sleep callback
281 * @param parent The parent sysctl under which to locate the sysctl
282 * @param name The name of the failpoint in the sysctl tree (and
284 * @param pre_func Function pointer to the pre-sleep function, which will be
285 * called directly before going to sleep.
286 * @param pre_arg Argument to the pre-sleep function
287 * @param post_func Function pointer to the pot-sleep function, which will be
288 * called directly before going to sleep.
289 * @param post_arg Argument to the post-sleep function
291 #define KFAIL_POINT_SLEEP_CALLBACKS(parent, name, pre_func, pre_arg, \
292 post_func, post_arg) \
293 KFAIL_POINT_CODE_SLEEP_CALLBACKS(parent, name, pre_func, \
294 pre_arg, post_func, post_arg, return RETURN_VALUE)
297 * Instantiate a failpoint which runs arbitrary code when triggered, and sets
298 * its pre- and post-sleep callback mechanisms
299 * @param parent The parent sysctl under which to locate the sysctl
300 * @param name The name of the failpoint in the sysctl tree (and
302 * @param pre_func Function pointer to the pre-sleep function, which will be
303 * called directly before going to sleep.
304 * @param pre_arg Argument to the pre-sleep function
305 * @param post_func Function pointer to the pot-sleep function, which will be
306 * called directly before going to sleep.
307 * @param post_arg Argument to the post-sleep function
308 * @param code The arbitrary code to run when triggered. Can reference
309 * "RETURN_VALUE" if desired to extract the specified
310 * user return-value when triggered. Note that this is
311 * implemented with a do-while loop so be careful of
312 * break and continue statements.
314 #define KFAIL_POINT_CODE_SLEEP_CALLBACKS(parent, name, pre_func, pre_arg, \
315 post_func, post_arg, code...) \
317 _FAIL_POINT_INIT(parent, name) \
318 _FAIL_POINT_NAME(name).fp_pre_sleep_fn = pre_func; \
319 _FAIL_POINT_NAME(name).fp_pre_sleep_arg = pre_arg; \
320 _FAIL_POINT_NAME(name).fp_post_sleep_fn = post_func; \
321 _FAIL_POINT_NAME(name).fp_post_sleep_arg = post_arg; \
322 _FAIL_POINT_EVAL(name, true, code) \
327 * Instantiate a failpoint which runs arbitrary code when triggered.
328 * @param parent The parent sysctl under which to locate the sysctl
329 * @param name The name of the failpoint in the sysctl tree
331 * @param code The arbitrary code to run when triggered. Can reference
332 * "RETURN_VALUE" if desired to extract the specified
333 * user return-value when triggered. Note that this is
334 * implemented with a do-while loop so be careful of
335 * break and continue statements.
337 #define KFAIL_POINT_CODE(parent, name, code...) \
339 _FAIL_POINT_INIT(parent, name, 0) \
340 _FAIL_POINT_EVAL(name, true, code) \
343 #define KFAIL_POINT_CODE_FLAGS(parent, name, flags, code...) \
345 _FAIL_POINT_INIT(parent, name, flags) \
346 _FAIL_POINT_EVAL(name, true, code) \
349 #define KFAIL_POINT_CODE_COND(parent, name, cond, flags, code...) \
351 _FAIL_POINT_INIT(parent, name, flags) \
352 _FAIL_POINT_EVAL(name, cond, code) \
357 * (end group failpoint)
361 int fail_point_sysctl(SYSCTL_HANDLER_ARGS);
362 int fail_point_sysctl_status(SYSCTL_HANDLER_ARGS);
364 /* The fail point sysctl tree. */
365 SYSCTL_DECL(_debug_fail_point);
366 #define DEBUG_FP _debug_fail_point
369 #endif /* _SYS_FAIL_H_ */