1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2009 Isilon Inc 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 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 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 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 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 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 * 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. 157 */ 158 static inline void 159 fail_point_use_timeout_path(struct fail_point *fp, bool use_timeout, 160 void (*post_sleep_fn)(void *)) 161 { 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")); 165 166 if (use_timeout) 167 fp->fp_flags |= FAIL_POINT_USE_TIMEOUT_PATH; 168 else 169 fp->fp_flags &= ~FAIL_POINT_USE_TIMEOUT_PATH; 170 171 if (post_sleep_fn != NULL) 172 fp->fp_post_sleep_fn = post_sleep_fn; 173 } 174 175 /** 176 * Free the resources used by a fail-point. Pair with fail_point_init(). 177 */ 178 void fail_point_destroy(struct fail_point *); 179 180 /** 181 * Evaluate a failpoint. 182 */ 183 static inline enum fail_point_return_code 184 fail_point_eval(struct fail_point *fp, int *ret) 185 { 186 if (__predict_true(fp->fp_setting == NULL)) 187 return (FAIL_POINT_RC_CONTINUE); 188 return (fail_point_eval_nontrivial(fp, ret)); 189 } 190 191 __END_DECLS 192 193 /* Declare a fail_point and its sysctl in a function. */ 194 #define _FAIL_POINT_NAME(name) _fail_point_##name 195 #define _FAIL_POINT_LOCATION() "(" __FILE__ ":" __XSTRING(__LINE__) ")" 196 #define _FAIL_POINT_INIT(parent, name, flags) \ 197 static struct fail_point _FAIL_POINT_NAME(name) = { \ 198 .fp_name = #name, \ 199 .fp_location = _FAIL_POINT_LOCATION(), \ 200 .fp_ref_cnt = 0, \ 201 .fp_setting = NULL, \ 202 .fp_flags = (flags), \ 203 .fp_pre_sleep_fn = NULL, \ 204 .fp_pre_sleep_arg = NULL, \ 205 .fp_post_sleep_fn = NULL, \ 206 .fp_post_sleep_arg = NULL, \ 207 }; \ 208 SYSCTL_OID(parent, OID_AUTO, name, \ 209 CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_MPSAFE, \ 210 &_FAIL_POINT_NAME(name), 0, fail_point_sysctl, \ 211 "A", ""); \ 212 SYSCTL_OID(parent, OID_AUTO, status_##name, \ 213 CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, \ 214 &_FAIL_POINT_NAME(name), 0, \ 215 fail_point_sysctl_status, "A", ""); 216 #define _FAIL_POINT_EVAL(name, cond, code...) \ 217 int RETURN_VALUE; \ 218 \ 219 if (__predict_false(cond && \ 220 fail_point_eval(&_FAIL_POINT_NAME(name), &RETURN_VALUE))) { \ 221 \ 222 code; \ 223 \ 224 } 225 226 227 /** 228 * Instantiate a failpoint which returns "RETURN_VALUE" from the function 229 * when triggered. 230 * @param parent The parent sysctl under which to locate the fp's sysctl 231 * @param name The name of the failpoint in the sysctl tree (and printouts) 232 * @return Instantly returns the RETURN_VALUE specified in the 233 * failpoint, if triggered. 234 */ 235 #define KFAIL_POINT_RETURN(parent, name) \ 236 KFAIL_POINT_CODE(parent, name, return RETURN_VALUE) 237 238 /** 239 * Instantiate a failpoint which returns (void) from the function when 240 * triggered. 241 * @param parent The parent sysctl under which to locate the sysctl 242 * @param name The name of the failpoint in the sysctl tree (and printouts) 243 * @return Instantly returns void, if triggered in the failpoint. 244 */ 245 #define KFAIL_POINT_RETURN_VOID(parent, name) \ 246 KFAIL_POINT_CODE(parent, name, return) 247 248 /** 249 * Instantiate a failpoint which sets an error when triggered. 250 * @param parent The parent sysctl under which to locate the sysctl 251 * @param name The name of the failpoint in the sysctl tree (and 252 * printouts) 253 * @param error_var A variable to set to the failpoint's specified 254 * return-value when triggered 255 */ 256 #define KFAIL_POINT_ERROR(parent, name, error_var) \ 257 KFAIL_POINT_CODE(parent, name, (error_var) = RETURN_VALUE) 258 259 /** 260 * Instantiate a failpoint which sets an error and then goes to a 261 * specified label in the function 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 * @param label The location to goto when triggered. 268 */ 269 #define KFAIL_POINT_GOTO(parent, name, error_var, label) \ 270 KFAIL_POINT_CODE(parent, name, (error_var) = RETURN_VALUE; goto label) 271 272 /** 273 * Instantiate a failpoint which sets its pre- and post-sleep callback 274 * mechanisms. 275 * @param parent The parent sysctl under which to locate the sysctl 276 * @param name The name of the failpoint in the sysctl tree (and 277 * printouts) 278 * @param pre_func Function pointer to the pre-sleep function, which will be 279 * called directly before going to sleep. 280 * @param pre_arg Argument to the pre-sleep function 281 * @param post_func Function pointer to the pot-sleep function, which will be 282 * called directly before going to sleep. 283 * @param post_arg Argument to the post-sleep function 284 */ 285 #define KFAIL_POINT_SLEEP_CALLBACKS(parent, name, pre_func, pre_arg, \ 286 post_func, post_arg) \ 287 KFAIL_POINT_CODE_SLEEP_CALLBACKS(parent, name, pre_func, \ 288 pre_arg, post_func, post_arg, return RETURN_VALUE) 289 290 /** 291 * Instantiate a failpoint which runs arbitrary code when triggered, and sets 292 * its pre- and post-sleep callback mechanisms 293 * @param parent The parent sysctl under which to locate the sysctl 294 * @param name The name of the failpoint in the sysctl tree (and 295 * printouts) 296 * @param pre_func Function pointer to the pre-sleep function, which will be 297 * called directly before going to sleep. 298 * @param pre_arg Argument to the pre-sleep function 299 * @param post_func Function pointer to the pot-sleep function, which will be 300 * called directly before going to sleep. 301 * @param post_arg Argument to the post-sleep function 302 * @param code The arbitrary code to run when triggered. Can reference 303 * "RETURN_VALUE" if desired to extract the specified 304 * user return-value when triggered. Note that this is 305 * implemented with a do-while loop so be careful of 306 * break and continue statements. 307 */ 308 #define KFAIL_POINT_CODE_SLEEP_CALLBACKS(parent, name, pre_func, pre_arg, \ 309 post_func, post_arg, code...) \ 310 do { \ 311 _FAIL_POINT_INIT(parent, name) \ 312 _FAIL_POINT_NAME(name).fp_pre_sleep_fn = pre_func; \ 313 _FAIL_POINT_NAME(name).fp_pre_sleep_arg = pre_arg; \ 314 _FAIL_POINT_NAME(name).fp_post_sleep_fn = post_func; \ 315 _FAIL_POINT_NAME(name).fp_post_sleep_arg = post_arg; \ 316 _FAIL_POINT_EVAL(name, true, code) \ 317 } while (0) 318 319 320 /** 321 * Instantiate a failpoint which runs arbitrary code when triggered. 322 * @param parent The parent sysctl under which to locate the sysctl 323 * @param name The name of the failpoint in the sysctl tree 324 * (and printouts) 325 * @param code The arbitrary code to run when triggered. Can reference 326 * "RETURN_VALUE" if desired to extract the specified 327 * user return-value when triggered. Note that this is 328 * implemented with a do-while loop so be careful of 329 * break and continue statements. 330 */ 331 #define KFAIL_POINT_CODE(parent, name, code...) \ 332 do { \ 333 _FAIL_POINT_INIT(parent, name, 0) \ 334 _FAIL_POINT_EVAL(name, true, code) \ 335 } while (0) 336 337 #define KFAIL_POINT_CODE_FLAGS(parent, name, flags, code...) \ 338 do { \ 339 _FAIL_POINT_INIT(parent, name, flags) \ 340 _FAIL_POINT_EVAL(name, true, code) \ 341 } while (0) 342 343 #define KFAIL_POINT_CODE_COND(parent, name, cond, flags, code...) \ 344 do { \ 345 _FAIL_POINT_INIT(parent, name, flags) \ 346 _FAIL_POINT_EVAL(name, cond, code) \ 347 } while (0) 348 349 /** 350 * @} 351 * (end group failpoint) 352 */ 353 354 #ifdef _KERNEL 355 int fail_point_sysctl(SYSCTL_HANDLER_ARGS); 356 int fail_point_sysctl_status(SYSCTL_HANDLER_ARGS); 357 358 /* The fail point sysctl tree. */ 359 SYSCTL_DECL(_debug_fail_point); 360 #define DEBUG_FP _debug_fail_point 361 #endif 362 363 #endif /* _SYS_FAIL_H_ */ 364