1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 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 * $FreeBSD$ 28 */ 29 /** 30 * @file 31 * 32 * Main header for failpoint facility. 33 */ 34 #ifndef _SYS_FAIL_H_ 35 #define _SYS_FAIL_H_ 36 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> 44 #include <sys/lock.h> 45 #include <sys/mutex.h> 46 #include <sys/systm.h> 47 48 /** 49 * Failpoint return codes, used internally. 50 * @ingroup failpoint_private 51 */ 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 */ 56 }; 57 58 struct fail_point_entry; 59 struct fail_point_setting; 60 61 /** 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 66 */ 67 struct fail_point { 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 74 */ 75 struct fail_point_setting * volatile fp_setting; 76 int fp_flags; 77 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; 82 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; 87 88 struct callout *fp_callout; 89 }; 90 91 #define FAIL_POINT_DYNAMIC_NAME 0x01 /**< Must free name on destroy */ 92 /**< Use timeout path for sleep instead of msleep */ 93 #define FAIL_POINT_USE_TIMEOUT_PATH 0x02 94 /**< If fail point is set to sleep, replace the sleep call with delay */ 95 #define FAIL_POINT_NONSLEEPABLE 0x04 96 97 #define FAIL_POINT_CV_DESC "fp cv no iterators" 98 #define FAIL_POINT_IS_OFF(fp) (__predict_true((fp)->fp_setting == NULL) || \ 99 __predict_true(fail_point_is_off(fp))) 100 101 __BEGIN_DECLS 102 103 /* Private failpoint eval function -- use fail_point_eval() instead. */ 104 enum fail_point_return_code fail_point_eval_nontrivial(struct fail_point *, 105 int *ret); 106 107 /** 108 * @addtogroup failpoint 109 * @{ 110 */ 111 /* 112 * Initialize a fail-point. The name is formed in printf-like fashion 113 * from "fmt" and the subsequent arguments. 114 * Pair with fail_point_destroy(). 115 */ 116 void fail_point_init(struct fail_point *, const char *fmt, ...) 117 __printflike(2, 3); 118 119 /* Return true iff this fail point is set to off, false otherwise */ 120 bool fail_point_is_off(struct fail_point *fp); 121 122 /** 123 * Set the pre-sleep function for a fail point 124 * If fp_post_sleep_fn is specified, then FAIL_POINT_SLEEP will result in a 125 * (*fp->fp_pre_sleep_fn)(fp->fp_pre_sleep_arg) call by the thread. 126 */ 127 static inline void 128 fail_point_sleep_set_pre_func(struct fail_point *fp, void (*sleep_fn)(void *)) 129 { 130 fp->fp_pre_sleep_fn = sleep_fn; 131 } 132 133 static inline void 134 fail_point_sleep_set_pre_arg(struct fail_point *fp, void *sleep_arg) 135 { 136 fp->fp_pre_sleep_arg = sleep_arg; 137 } 138 139 /** 140 * Set the post-sleep function. This will be passed to timeout if we take 141 * the timeout path. This must be set if you sleep using the timeout path. 142 */ 143 static inline void 144 fail_point_sleep_set_post_func(struct fail_point *fp, void (*sleep_fn)(void *)) 145 { 146 fp->fp_post_sleep_fn = sleep_fn; 147 } 148 149 static inline void 150 fail_point_sleep_set_post_arg(struct fail_point *fp, void *sleep_arg) 151 { 152 fp->fp_post_sleep_arg = sleep_arg; 153 } 154 155 void fail_point_alloc_callout(struct fail_point *); 156 157 /** 158 * If the FAIL_POINT_USE_TIMEOUT flag is set on a failpoint, then 159 * FAIL_POINT_SLEEP will result in a call to callout_reset instead of 160 * msleep. Note that if you sleep while this flag is set, you must 161 * set fp_post_sleep_fn or an error will occur upon waking. 162 */ 163 static inline void 164 fail_point_use_timeout_path(struct fail_point *fp, bool use_timeout, 165 void (*post_sleep_fn)(void *)) 166 { 167 KASSERT(!use_timeout || post_sleep_fn != NULL || 168 (post_sleep_fn == NULL && fp->fp_post_sleep_fn != NULL), 169 ("Setting fp to use timeout, but not setting post_sleep_fn\n")); 170 171 if (use_timeout) { 172 fail_point_alloc_callout(fp); 173 fp->fp_flags |= FAIL_POINT_USE_TIMEOUT_PATH; 174 } else 175 fp->fp_flags &= ~FAIL_POINT_USE_TIMEOUT_PATH; 176 177 if (post_sleep_fn != NULL) 178 fp->fp_post_sleep_fn = post_sleep_fn; 179 } 180 181 /** 182 * Free the resources used by a fail-point. Pair with fail_point_init(). 183 */ 184 void fail_point_destroy(struct fail_point *); 185 186 /** 187 * Evaluate a failpoint. 188 */ 189 static inline enum fail_point_return_code 190 fail_point_eval(struct fail_point *fp, int *ret) 191 { 192 if (__predict_true(fp->fp_setting == NULL)) 193 return (FAIL_POINT_RC_CONTINUE); 194 return (fail_point_eval_nontrivial(fp, ret)); 195 } 196 197 __END_DECLS 198 199 /* Declare a fail_point and its sysctl in a function. */ 200 #define KFAIL_POINT_DECLARE(name) \ 201 extern struct fail_point _FAIL_POINT_NAME(name) 202 #define _FAIL_POINT_NAME(name) _fail_point_##name 203 #define _FAIL_POINT_LOCATION() "(" __FILE__ ":" __XSTRING(__LINE__) ")" 204 #define KFAIL_POINT_DEFINE(parent, name, flags) \ 205 struct fail_point _FAIL_POINT_NAME(name) = { \ 206 .fp_name = #name, \ 207 .fp_location = _FAIL_POINT_LOCATION(), \ 208 .fp_ref_cnt = 0, \ 209 .fp_setting = NULL, \ 210 .fp_flags = (flags), \ 211 .fp_pre_sleep_fn = NULL, \ 212 .fp_pre_sleep_arg = NULL, \ 213 .fp_post_sleep_fn = NULL, \ 214 .fp_post_sleep_arg = NULL, \ 215 }; \ 216 SYSCTL_OID(parent, OID_AUTO, name, \ 217 CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_MPSAFE, \ 218 &_FAIL_POINT_NAME(name), 0, fail_point_sysctl, \ 219 "A", ""); \ 220 SYSCTL_OID(parent, OID_AUTO, status_##name, \ 221 CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, \ 222 &_FAIL_POINT_NAME(name), 0, \ 223 fail_point_sysctl_status, "A", ""); 224 225 #define _FAIL_POINT_INIT(parent, name, flags) \ 226 static KFAIL_POINT_DEFINE(parent, name, flags) 227 #define _FAIL_POINT_EVAL(name, cond, code...) \ 228 int RETURN_VALUE; \ 229 \ 230 if (__predict_false(cond && \ 231 fail_point_eval(&_FAIL_POINT_NAME(name), &RETURN_VALUE))) { \ 232 \ 233 code; \ 234 \ 235 } 236 #define KFAIL_POINT_EVAL(name, code...) \ 237 _FAIL_POINT_EVAL(name, true, code) 238 239 /** 240 * Instantiate a failpoint which returns "RETURN_VALUE" from the function 241 * when triggered. 242 * @param parent The parent sysctl under which to locate the fp's sysctl 243 * @param name The name of the failpoint in the sysctl tree (and printouts) 244 * @return Instantly returns the RETURN_VALUE specified in the 245 * failpoint, if triggered. 246 */ 247 #define KFAIL_POINT_RETURN(parent, name) \ 248 KFAIL_POINT_CODE(parent, name, return RETURN_VALUE) 249 250 /** 251 * Instantiate a failpoint which returns (void) from the function when 252 * triggered. 253 * @param parent The parent sysctl under which to locate the sysctl 254 * @param name The name of the failpoint in the sysctl tree (and printouts) 255 * @return Instantly returns void, if triggered in the failpoint. 256 */ 257 #define KFAIL_POINT_RETURN_VOID(parent, name) \ 258 KFAIL_POINT_CODE(parent, name, return) 259 260 /** 261 * Instantiate a failpoint which sets an error when triggered. 262 * @param parent The parent sysctl under which to locate the sysctl 263 * @param name The name of the failpoint in the sysctl tree (and 264 * printouts) 265 * @param error_var A variable to set to the failpoint's specified 266 * return-value when triggered 267 */ 268 #define KFAIL_POINT_ERROR(parent, name, error_var) \ 269 KFAIL_POINT_CODE(parent, name, (error_var) = RETURN_VALUE) 270 271 /** 272 * Instantiate a failpoint which sets an error and then goes to a 273 * specified label in the function when triggered. 274 * @param parent The parent sysctl under which to locate the sysctl 275 * @param name The name of the failpoint in the sysctl tree (and 276 * printouts) 277 * @param error_var A variable to set to the failpoint's specified 278 * return-value when triggered 279 * @param label The location to goto when triggered. 280 */ 281 #define KFAIL_POINT_GOTO(parent, name, error_var, label) \ 282 KFAIL_POINT_CODE(parent, name, (error_var) = RETURN_VALUE; goto label) 283 284 /** 285 * Instantiate a failpoint which sets its pre- and post-sleep callback 286 * mechanisms. 287 * @param parent The parent sysctl under which to locate the sysctl 288 * @param name The name of the failpoint in the sysctl tree (and 289 * printouts) 290 * @param pre_func Function pointer to the pre-sleep function, which will be 291 * called directly before going to sleep. 292 * @param pre_arg Argument to the pre-sleep function 293 * @param post_func Function pointer to the pot-sleep function, which will be 294 * called directly before going to sleep. 295 * @param post_arg Argument to the post-sleep function 296 */ 297 #define KFAIL_POINT_SLEEP_CALLBACKS(parent, name, pre_func, pre_arg, \ 298 post_func, post_arg) \ 299 KFAIL_POINT_CODE_SLEEP_CALLBACKS(parent, name, pre_func, \ 300 pre_arg, post_func, post_arg, return RETURN_VALUE) 301 302 /** 303 * Instantiate a failpoint which runs arbitrary code when triggered, and sets 304 * its pre- and post-sleep callback mechanisms 305 * @param parent The parent sysctl under which to locate the sysctl 306 * @param name The name of the failpoint in the sysctl tree (and 307 * printouts) 308 * @param pre_func Function pointer to the pre-sleep function, which will be 309 * called directly before going to sleep. 310 * @param pre_arg Argument to the pre-sleep function 311 * @param post_func Function pointer to the pot-sleep function, which will be 312 * called directly before going to sleep. 313 * @param post_arg Argument to the post-sleep function 314 * @param code The arbitrary code to run when triggered. Can reference 315 * "RETURN_VALUE" if desired to extract the specified 316 * user return-value when triggered. Note that this is 317 * implemented with a do-while loop so be careful of 318 * break and continue statements. 319 */ 320 #define KFAIL_POINT_CODE_SLEEP_CALLBACKS(parent, name, pre_func, pre_arg, \ 321 post_func, post_arg, code...) \ 322 do { \ 323 _FAIL_POINT_INIT(parent, name) \ 324 _FAIL_POINT_NAME(name).fp_pre_sleep_fn = pre_func; \ 325 _FAIL_POINT_NAME(name).fp_pre_sleep_arg = pre_arg; \ 326 _FAIL_POINT_NAME(name).fp_post_sleep_fn = post_func; \ 327 _FAIL_POINT_NAME(name).fp_post_sleep_arg = post_arg; \ 328 _FAIL_POINT_EVAL(name, true, code) \ 329 } while (0) 330 331 /** 332 * Instantiate a failpoint which runs arbitrary code when triggered. 333 * @param parent The parent sysctl under which to locate the sysctl 334 * @param name The name of the failpoint in the sysctl tree 335 * (and printouts) 336 * @param code The arbitrary code to run when triggered. Can reference 337 * "RETURN_VALUE" if desired to extract the specified 338 * user return-value when triggered. Note that this is 339 * implemented with a do-while loop so be careful of 340 * break and continue statements. 341 */ 342 #define KFAIL_POINT_CODE(parent, name, code...) \ 343 do { \ 344 _FAIL_POINT_INIT(parent, name, 0) \ 345 _FAIL_POINT_EVAL(name, true, code) \ 346 } while (0) 347 348 #define KFAIL_POINT_CODE_FLAGS(parent, name, flags, code...) \ 349 do { \ 350 _FAIL_POINT_INIT(parent, name, flags) \ 351 _FAIL_POINT_EVAL(name, true, code) \ 352 } while (0) 353 354 #define KFAIL_POINT_CODE_COND(parent, name, cond, flags, code...) \ 355 do { \ 356 _FAIL_POINT_INIT(parent, name, flags) \ 357 _FAIL_POINT_EVAL(name, cond, code) \ 358 } while (0) 359 360 /** 361 * @} 362 * (end group failpoint) 363 */ 364 365 #ifdef _KERNEL 366 int fail_point_sysctl(SYSCTL_HANDLER_ARGS); 367 int fail_point_sysctl_status(SYSCTL_HANDLER_ARGS); 368 369 /* The fail point sysctl tree. */ 370 SYSCTL_DECL(_debug_fail_point); 371 #define DEBUG_FP _debug_fail_point 372 #endif 373 374 #endif /* _SYS_FAIL_H_ */ 375