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         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_ */