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