sys/sys/fail.h

   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
  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 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) = { \
 200                 .fp_name = #name, \
 201                 .fp_location = _FAIL_POINT_LOCATION(), \
 202                 .fp_ref_cnt = 0, \
 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, \
 209         }; \
 210         SYSCTL_OID(parent, OID_AUTO, name, \
 211                 CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_MPSAFE, \
 212                 &_FAIL_POINT_NAME(name), 0, fail_point_sysctl, \
 213                 "A", ""); \
 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", "");
 218
 219 #define _FAIL_POINT_INIT(parent, name, flags) \
 220         static KFAIL_POINT_DEFINE(parent, name, flags)
 221 #define _FAIL_POINT_EVAL(name, cond, code...) \
 222         int RETURN_VALUE; \
 223  \
 224         if (__predict_false(cond && \
 225                 fail_point_eval(&_FAIL_POINT_NAME(name), &RETURN_VALUE))) { \
 226  \
 227                 code; \
 228  \
 229         }
 230 #define KFAIL_POINT_EVAL(name, code...) \
 231         _FAIL_POINT_EVAL(name, true, code)
 232
 233 /**
 234  * Instantiate a failpoint which returns "RETURN_VALUE" from the function
 235  * when triggered.
 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.
 240  */
 241 #define KFAIL_POINT_RETURN(parent, name) \
 242         KFAIL_POINT_CODE(parent, name, return RETURN_VALUE)
 243
 244 /**
 245  * Instantiate a failpoint which returns (void) from the function when
 246  * triggered.
 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.
 250  */
 251 #define KFAIL_POINT_RETURN_VOID(parent, name) \
 252         KFAIL_POINT_CODE(parent, name, return)
 253
 254 /**
 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
 258  *                   printouts)
 259  * @param error_var  A variable to set to the failpoint's specified
 260  *                   return-value when triggered
 261  */
 262 #define KFAIL_POINT_ERROR(parent, name, error_var) \
 263         KFAIL_POINT_CODE(parent, name, (error_var) = RETURN_VALUE)
 264
 265 /**
 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
 270  *                   printouts)
 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.
 274  */
 275 #define KFAIL_POINT_GOTO(parent, name, error_var, label) \
 276         KFAIL_POINT_CODE(parent, name, (error_var) = RETURN_VALUE; goto label)
 277
 278 /**
 279  * Instantiate a failpoint which sets its pre- and post-sleep callback
 280  * mechanisms.
 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
 283  *                   printouts)
 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
 290  */
 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)
 295
 296 /**
 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
 301  *                   printouts)
 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.
 313  */
 314 #define KFAIL_POINT_CODE_SLEEP_CALLBACKS(parent, name, pre_func, pre_arg, \
 315         post_func, post_arg, code...) \
 316         do { \
 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) \
 323         } while (0)
 324
 325
 326 /**
 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
 330  *                   (and printouts)
 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.
 336  */
 337 #define KFAIL_POINT_CODE(parent, name, code...) \
 338         do { \
 339                 _FAIL_POINT_INIT(parent, name, 0) \
 340                 _FAIL_POINT_EVAL(name, true, code) \
 341         } while (0)
 342
 343 #define KFAIL_POINT_CODE_FLAGS(parent, name, flags, code...) \
 344         do { \
 345                 _FAIL_POINT_INIT(parent, name, flags) \
 346                 _FAIL_POINT_EVAL(name, true, code) \
 347         } while (0)
 348
 349 #define KFAIL_POINT_CODE_COND(parent, name, cond, flags, code...) \
 350         do { \
 351                 _FAIL_POINT_INIT(parent, name, flags) \
 352                 _FAIL_POINT_EVAL(name, cond, code) \
 353         } while (0)
 354
 355 /**
 356  * @}
 357  * (end group failpoint)
 358  */
 359
 360 #ifdef _KERNEL
 361 int fail_point_sysctl(SYSCTL_HANDLER_ARGS);
 362 int fail_point_sysctl_status(SYSCTL_HANDLER_ARGS);
 363
 364 /* The fail point sysctl tree. */
 365 SYSCTL_DECL(_debug_fail_point);
 366 #define DEBUG_FP        _debug_fail_point
 367 #endif
 368
 369 #endif /* _SYS_FAIL_H_ */