1 /* ex - Exception Handling */
3 /* Copyright (c) 2005-2015. The SimGrid Team.
4 * All rights reserved. */
6 /* Copyright (c) 2002-2004 Ralf S. Engelschall <rse@engelschall.com> */
7 /* Copyright (c) 2002-2004 The OSSP Project <http://www.ossp.org/> */
8 /* Copyright (c) 2002-2004 Cable & Wireless <http://www.cw.com/> */
9 /* All rights reserved. */
11 /* This code is inspirated from the OSSP version (as retrieved back in 2004)*/
12 /* It was heavily modified to fit the SimGrid framework. */
14 /* The OSSP version has the following copyright notice:
15 ** OSSP ex - Exception Handling
16 ** Copyright (c) 2002-2004 Ralf S. Engelschall <rse@engelschall.com>
17 ** Copyright (c) 2002-2004 The OSSP Project <http://www.ossp.org/>
18 ** Copyright (c) 2002-2004 Cable & Wireless <http://www.cw.com/>
20 ** This file is part of OSSP ex, an exception handling library
21 ** which can be found at http://www.ossp.org/pkg/lib/ex/.
23 ** Permission to use, copy, modify, and distribute this software for
24 ** any purpose with or without fee is hereby granted, provided that
25 ** the above copyright notice and this permission notice appear in all
28 ** THIS SOFTWARE IS PROVIDED `AS IS'' AND ANY EXPRESSED OR IMPLIED
29 ** WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
30 ** MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
31 ** IN NO EVENT SHALL THE AUTHORS AND COPYRIGHT HOLDERS AND THEIR
32 ** CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
33 ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
34 ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
35 ** USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
36 ** ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
37 ** OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
38 ** OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
42 /* The extensions made for the SimGrid project can either be distributed */
43 /* under the same license, or under the LGPL v2.1 */
48 #include "xbt/sysdep.h"
50 #include "xbt/virtu.h"
54 /*-*-* Emergency debuging: define this when the exceptions get crazy *-*-*/
59 # define MAYDAY_SAVE(m) printf("%d %s:%d save %p\n", \
60 xbt_getpid(), __FILE__, __LINE__, \
63 # define MAYDAY_RESTORE(m) printf("%d %s:%d restore %p\n", \
64 xbt_getpid(), __FILE__, __LINE__, \
67 # define MAYDAY_CATCH(e) printf("%d %s:%d Catched '%s'\n", \
68 xbt_getpid(), __FILE__, __LINE__, \
72 # define MAYDAY_SAVE(m)
73 # define MAYDAY_RESTORE(m)
74 # define MAYDAY_CATCH(e)
76 /*-*-* end of debugging stuff *-*-*/
77 #if defined(__EX_MCTX_MCSC__)
78 #include <ucontext.h> /* POSIX.1 ucontext(3) */
79 #define __ex_mctx_struct ucontext_t uc;
80 #define __ex_mctx_save(mctx) (getcontext(&(mctx)->uc) == 0)
81 #define __ex_mctx_restored(mctx) /* noop */
82 #define __ex_mctx_restore(mctx) (void)setcontext(&(mctx)->uc)
83 #elif defined(__EX_MCTX_SSJLJ__)
84 #include <setjmp.h> /* POSIX.1 sigjmp_buf(3) */
85 #define __ex_mctx_struct sigjmp_buf jb;
86 #define __ex_mctx_save(mctx) (sigsetjmp((mctx)->jb, 1) == 0)
87 #define __ex_mctx_restored(mctx) /* noop */
88 #define __ex_mctx_restore(mctx) (void)siglongjmp((mctx)->jb, 1)
89 #elif defined(__EX_MCTX_SJLJ__) || !defined(__EX_MCTX_CUSTOM__) || defined(__EX_MAYDAY)
90 #include <setjmp.h> /* ISO-C jmp_buf(3) */
91 #define __ex_mctx_struct jmp_buf jb;
92 #define __ex_mctx_save(mctx) ( MAYDAY_SAVE(mctx) setjmp((mctx)->jb) == 0)
93 #define __ex_mctx_restored(mctx) /* noop */
94 #define __ex_mctx_restore(mctx) ( MAYDAY_RESTORE(mctx) (void)longjmp((mctx)->jb, 1))
96 /* declare the machine context type */
98 __ex_mctx_struct} __ex_mctx_t;
100 /** @addtogroup XBT_ex
101 * @brief A set of macros providing exception a la C++ in ANSI C (grounding feature)
103 * This module is a small ISO-C++ style exception handling library
104 * for use in the ISO-C language. It allows you to use the paradigm
105 * of throwing and catching exceptions in order to reduce the amount
106 * of error handling code without hindering program robustness.
108 * This is achieved by directly transferring exceptional return codes
109 * (and the program control flow) from the location where the exception
110 * is raised (throw point) to the location where it is handled (catch
111 * point) -- usually from a deeply nested sub-routine to a parent
112 * routine. All intermediate routines no longer have to make sure that
113 * the exceptional return codes from sub-routines are correctly passed
114 * back to the parent.
116 * These features are brought to you by a modified version of the libex
117 * library, one of the numerous masterpiece of Ralf S. Engelschall.
119 * \htmlonly <div class="toc">\endhtmlonly
121 * @section XBT_ex_toc TABLE OF CONTENTS
123 * - \ref XBT_ex_intro
125 * - \ref XBT_ex_pitfalls
127 * \htmlonly </div> \endhtmlonly
129 * @section XBT_ex_intro DESCRIPTION
131 * In SimGrid, an exception is a triple <\a msg , \a category , \a value>
132 * where \a msg is a human-readable text describing the exceptional
133 * condition, \a code an integer describing what went wrong and \a value
134 * providing a sort of sub-category. (this is different in the original libex).
136 * @section XBT_ex_base BASIC USAGE
138 * \em TRY \b TRIED_BLOCK [\em TRY_CLEANUP \b CLEANUP_BLOCK] \em CATCH (variable) \b CATCH_BLOCK
140 * This is the primary syntactical construct provided. It is modeled after the
141 * ISO-C++ try-catch clause and should sound familiar to most of you.
143 * Any exception thrown directly from the TRIED_BLOCK block or from called
144 * subroutines is caught. Cleanups which must be done after this block
145 * (whenever an exception arose or not) should be placed into the optionnal
146 * CLEANUP_BLOCK. The code dealing with the exceptions when they arise should
147 * be placed into the (mandatory) CATCH_BLOCK.
150 * In absence of exception, the control flow goes into the blocks TRIED_BLOCK
151 * and CLEANUP_BLOCK (if present); The CATCH_BLOCK block is then ignored.
153 * When an exception is thrown, the control flow goes through the following
154 * blocks: TRIED_BLOCK (up to the statement throwing the exception),
155 * CLEANUP_BLOCK (if any) and CATCH_BLOCK. The exception is stored in a
156 * variable for inspection inside the CATCH_BLOCK. This variable must be
157 * declared in the outter scope, but its value is only valid within the
161 * - TRY, CLEANUP and CATCH cannot be used separately, they work
162 * only in combination and form a language clause as a whole.
163 * - In contrast to the syntax of other languages (such as C++ or Jave) there
164 * is only one CATCH block and not multiple ones (all exceptions are
165 * of the same \em xbt_ex_t C type).
166 * - the variable of CATCH can naturally be reused in subsequent
168 * - it is possible to nest TRY clauses.
170 * The TRY block is a regular ISO-C language statement block, but
172 * <center><b>it is not
173 * allowed to jump into it via "goto" or longjmp(3) or out of it via "break",
174 * "return", "goto" or longjmp(3)</b>.</center>
176 * This is because there is some hidden setup and
177 * cleanup that needs to be done regardless of whether an exception is
178 * caught. Bypassing these steps will break the exception handling facility.
179 * The symptom are likely to be a segfault at the next exception raising point,
180 * ie far away from the point where you did the mistake. If you suspect
181 * that kind of error in your code, have a look at the little script
182 * <tt>tools/xbt_exception_checker</tt> in the CVS. It extracts all the TRY
183 * blocks from a set of C files you give it and display them (and only
184 * them) on the standard output. You can then grep for the forbidden
185 * keywords on that output.
187 * The CLEANUP and CATCH blocks are regular ISO-C language statement
188 * blocks without any restrictions. You are even allowed to throw (and, in the
189 * CATCH block, to re-throw) exceptions.
191 * There is one subtle detail you should remember about TRY blocks:
192 * Variables used in the CLEANUP or CATCH clauses must be declared with
193 * the storage class "volatile", otherwise they might contain outdated
194 * information if an exception is thrown.
197 * This is because you usually do not know which commands in the TRY
198 * were already successful before the exception was thrown (logically speaking)
199 * and because the underlying ISO-C setjmp(3) facility applies those
200 * restrictions (technically speaking). As a matter of fact, value changes
201 * between the TRY and the THROW may be discarded if you forget the
202 * "volatile" keyword.
204 * \section XBT_ex_pitfalls PROGRAMMING PITFALLS
206 * Exception handling is a very elegant and efficient way of dealing with
207 * exceptional situation. Nevertheless it requires additional discipline in
208 * programming and there are a few pitfalls one must be aware of. Look the
209 * following code which shows some pitfalls and contains many errors (assuming
210 * a mallocex() function which throws an exception if malloc(3) fails):
214 * \until end_of_bad_example
216 * This example raises a few issues:
217 * -# \b variable \b scope \n
218 * Variables which are used in the CLEANUP or CATCH clauses must be
219 * declared before the TRY clause, otherwise they only exist inside the
220 * TRY block. In the example above, cp1, cp2 and cp3 only exist in the
221 * TRY block and are invisible from the CLEANUP and CATCH
223 * -# \b variable \b initialization \n
224 * Variables which are used in the CLEANUP or CATCH clauses must
225 * be initialized before the point of the first possible THROW is
226 * reached. In the example above, CLEANUP would have trouble using cp3
227 * if mallocex() throws a exception when allocating a TOOBIG buffer.
228 * -# \b volatile \b variable \n
229 * Variables which are used in the CLEANUP or CATCH clauses MUST BE
230 * DECLARED AS "volatile", otherwise they might contain outdated
231 * information when an exception is thrown.
232 * -# \b clean \b before \b catch \n
233 * The CLEANUP clause is not only place before the CATCH clause in
234 * the source code, it also occures before in the control flow. So,
235 * resources being cleaned up cannot be used in the CATCH block. In the
236 * example, c3 gets freed before the printf placed in CATCH.
237 * -# \b variable \b uninitialization \n
238 * If resources are passed out of the scope of the
239 * TRY/CLEANUP/CATCH construct, they naturally shouldn't get
240 * cleaned up. The example above does free(3) cp1 in CLEANUP although
241 * its value was affected to globalcontext->first, invalidating this
244 * The following is fixed version of the code (annotated with the pitfall items
248 * \until end_of_good_example
253 /** @brief different kind of errors */
255 unknown_error = 0, /**< unknown error */
256 arg_error, /**< Invalid argument */
257 bound_error, /**< Out of bounds argument */
258 mismatch_error, /**< The provided ID does not match */
259 not_found_error, /**< The searched element was not found */
260 system_error, /**< a syscall did fail */
261 network_error, /**< error while sending/receiving data */
262 timeout_error, /**< not quick enough, dude */
263 cancel_error, /**< an action was canceled */
264 thread_error, /**< error while [un]locking */
265 host_error, /**< host failed */
266 tracing_error, /**< error during the simulation tracing */
267 io_error, /**< disk or file error */
268 vm_error /**< vm error */
271 XBT_PUBLIC(const char *) xbt_ex_catname(xbt_errcat_t cat);
273 /** @brief Structure describing an exception */
275 char *msg; /**< human readable message */
276 xbt_errcat_t category; /**< category like HTTP (what went wrong) */
277 int value; /**< like errno (why did it went wrong) */
279 char *procname; /**< Name of the process who thrown this */
280 int pid; /**< PID of the process who thrown this */
281 char *file; /**< Thrown point */
282 int line; /**< Thrown point */
283 char *func; /**< Thrown point */
286 char **bt_strings; /* only filed on display (or before the network propagation) */
287 void *bt[XBT_BACKTRACE_SIZE];
290 /* declare the running context type
291 * (that's where we get the process name for the logs and the exception storage)
292 * -- do not mess with it --
294 typedef struct xbt_running_ctx_t {
295 __ex_mctx_t *ctx_mctx; /* permanent machine context of enclosing try/catch */
296 int ctx_caught; /* temporary flag whether exception was caught */
297 volatile xbt_ex_t exception; /* temporary exception storage */
300 /* the static and dynamic initializers for a context structure */
301 #define XBT_RUNNING_CTX_INITIALIZER \
302 { NULL, 0, { /* content */ NULL, unknown_error, 0, \
303 /* throw point*/ NULL, 0, NULL, 0, NULL, \
304 /* backtrace */ 0, NULL, /* bt[] */ } }
306 XBT_PUBLIC_DATA(const xbt_running_ctx_t) __xbt_ex_ctx_initializer;
308 // #define XBT_RUNNING_CTX_INITIALIZE(ctx) (*(ctx) = __xbt_ex_ctx_initializer)
310 #define XBT_RUNNING_CTX_INITIALIZE(ctx) \
311 (ctx)->ctx_mctx = NULL; \
312 (ctx)->ctx_caught = 0; \
313 (ctx)->exception.msg = NULL; \
314 (ctx)->exception.category = unknown_error; \
315 (ctx)->exception.value = 0; \
316 (ctx)->exception.procname = NULL; \
317 (ctx)->exception.pid = 0; \
318 (ctx)->exception.file = NULL; \
319 (ctx)->exception.line = 0; \
320 (ctx)->exception.used = 0; \
321 (ctx)->exception.bt_strings = NULL;
323 /* the exception context */
324 typedef xbt_running_ctx_t *(*xbt_running_ctx_fetcher_t) (void);
325 XBT_PUBLIC_DATA(xbt_running_ctx_fetcher_t) __xbt_running_ctx_fetch;
326 XBT_PUBLIC( xbt_running_ctx_t *)__xbt_ex_ctx_default(void);
328 /* the termination handler */
329 typedef void (*ex_term_cb_t) (xbt_ex_t *);
330 XBT_PUBLIC_DATA(ex_term_cb_t) __xbt_ex_terminate;
331 XBT_PUBLIC( void )__xbt_ex_terminate_default(xbt_ex_t * e);
333 /** @brief Introduce a block where exception may be dealed with
338 xbt_running_ctx_t *__xbt_ex_ctx_ptr = __xbt_running_ctx_fetch(); \
339 int __ex_cleanup = 0; \
340 __ex_mctx_t __ex_mctx_me; \
341 __ex_mctx_t * __ex_mctx_en = __xbt_ex_ctx_ptr->ctx_mctx; \
342 __xbt_ex_ctx_ptr->ctx_mctx = &__ex_mctx_me; \
343 if (__ex_mctx_save(&__ex_mctx_me)) { \
346 /** @brief optional(!) block for cleanup
349 #define TRY_CLEANUP \
352 __xbt_ex_ctx_ptr->ctx_caught = 0; \
354 __ex_mctx_restored(&__ex_mctx_me); \
355 __xbt_ex_ctx_ptr->ctx_caught = 1; \
357 __xbt_ex_ctx_ptr->ctx_mctx = __ex_mctx_en; \
364 # define XBT_EX_T_CPLUSPLUSCAST (xbt_ex_t&)
366 # define XBT_EX_T_CPLUSPLUSCAST
370 /** @brief the block for catching (ie, deal with) an exception
374 DO_CATCH((e) = XBT_EX_T_CPLUSPLUSCAST __xbt_running_ctx_fetch()->exception)
376 /** @brief like CATCH(e) but without argument
379 * Useful if you only want to rethrow the exception caught, and do not want to
380 * bother with an unused variable.
382 #define CATCH_ANONYMOUS DO_CATCH(0)
384 #define DO_CATCH(_xbt_do_catch_set_e) \
387 if (!(__ex_cleanup)) \
388 __xbt_ex_ctx_ptr->ctx_caught = 0; \
390 if (!(__ex_cleanup)) { \
391 __ex_mctx_restored(&__ex_mctx_me); \
392 __xbt_ex_ctx_ptr->ctx_caught = 1; \
395 __xbt_ex_ctx_ptr->ctx_mctx = __ex_mctx_en; \
397 if ( !(__xbt_running_ctx_fetch()->ctx_caught) \
398 || ((void)(_xbt_do_catch_set_e), \
399 MAYDAY_CATCH(__xbt_running_ctx_fetch()->exception) 0)) { \
403 #define DO_THROW(running_ctx) \
404 do { /* deal with the exception */ \
405 xbt_running_ctx_t *ctx = (running_ctx); \
406 if (ctx->ctx_mctx == NULL) \
407 __xbt_ex_terminate((xbt_ex_t*)&(ctx->exception)); /* not catched */ \
409 __ex_mctx_restore(ctx->ctx_mctx); /* catched somewhere */ \
410 abort(); /* nope, stupid GCC, we won't survive a THROW */ \
411 /* (this won't be reached) */ \
414 /** @brief Helper macro for THROW and THROWF
417 * @param _throw_ctx: the throwing context in which we should construct the exception
418 * @param c: category code (integer)
419 * @param v: value (integer)
420 * @param m: message text
422 * If called from within a TRY/CATCH construct, this exception
423 * is copied into the CATCH relevant variable program control flow
424 * is derouted to the CATCH (after the optional sg_cleanup).
426 * If no TRY/CATCH construct embeds this call, the program calls
429 * The THROW can be performed everywhere, including inside TRY,
430 * CLEANUP and CATCH blocks.
433 #define THROW_PREPARE(_throw_ctx, c, v, m) \
434 /* build the exception */ \
435 _throw_ctx->exception.msg = (m); \
436 _throw_ctx->exception.category = (xbt_errcat_t)(c); \
437 _throw_ctx->exception.value = (v); \
438 _throw_ctx->exception.procname = (char*)xbt_procname(); \
439 _throw_ctx->exception.pid = xbt_getpid(); \
440 _throw_ctx->exception.file = (char*)__FILE__; \
441 _throw_ctx->exception.line = __LINE__; \
442 _throw_ctx->exception.func = (char*)_XBT_FUNCTION; \
443 _throw_ctx->exception.bt_strings = NULL; \
444 xbt_backtrace_current((xbt_ex_t *)&(_throw_ctx->exception));
446 #define _XBT_THROW(c, v, m) \
447 do { /* change this sequence into one block */ \
448 xbt_running_ctx_t *_throw_ctx = __xbt_running_ctx_fetch(); \
449 THROW_PREPARE(_throw_ctx, c, v, m); \
450 DO_THROW(_throw_ctx); \
453 /** @brief Builds and throws an exception
455 #define THROW(c, v) _XBT_THROW(c, v, NULL)
457 /** @brief Builds and throws an exception with a printf-like formatted message
459 #define THROWF(c, v, ...) _XBT_THROW(c, v, bprintf(__VA_ARGS__))
461 #define THROW_IMPOSSIBLE \
462 THROWF(unknown_error, 0, "The Impossible Did Happen (yet again)")
463 #define THROW_UNIMPLEMENTED \
464 THROWF(unknown_error, 0, "Function %s unimplemented",_XBT_FUNCTION)
465 #define THROW_DEADCODE \
466 THROWF(unknown_error, 0, "Function %s was supposed to be DEADCODE, but it's not",_XBT_FUNCTION)
468 #define DIE_IMPOSSIBLE xbt_die("The Impossible Did Happen (yet again)")
470 /** @brief re-throwing of an already caught exception (ie, pass it to the upper catch block)
473 #define RETHROW DO_THROW(__xbt_running_ctx_fetch())
475 /** @brief like THROWF, but adding some details to the message of an existing exception
478 #define RETHROWF(...) \
480 char *_xbt_ex_internal_msg = __xbt_running_ctx_fetch()->exception.msg; \
481 __xbt_running_ctx_fetch()->exception.msg = bprintf(__VA_ARGS__, \
482 _xbt_ex_internal_msg); \
483 free(_xbt_ex_internal_msg); \
487 /** @brief Exception destructor */
488 XBT_PUBLIC(void) xbt_ex_free(xbt_ex_t e);
489 /** @brief The display made by an exception that is not catched */
490 XBT_PUBLIC(void) xbt_ex_display(xbt_ex_t * e);
492 /** @brief Shows a backtrace of the current location */
493 XBT_PUBLIC(void) xbt_backtrace_display_current(void);
494 /** @brief reimplementation of glibc backtrace based directly on gcc library, without implicit malloc */
495 XBT_PUBLIC(int) xbt_backtrace_no_malloc(void**bt, int size);
496 /** @brief Captures a backtrace for further use */
497 XBT_PUBLIC(void) xbt_backtrace_current(xbt_ex_t * e);
498 /** @brief Display a previously captured backtrace */
499 XBT_PUBLIC(void) xbt_backtrace_display(xbt_ex_t * e);
500 /** @brief Get current backtrace with libunwind */
501 XBT_PUBLIC(int) xbt_libunwind_backtrace(void *bt[XBT_BACKTRACE_SIZE], int size);
503 #ifdef XBT_USE_DEPRECATED
505 /* Kept for backward compatibility. */
507 #define THROW0(c, v, m) \
508 do { if (m) THROWF(c, v, m); else THROW(c, v); } while (0)
509 #define THROW1(c, v, ...) THROWF(c, v, __VA_ARGS__)
510 #define THROW2(c, v, ...) THROWF(c, v, __VA_ARGS__)
511 #define THROW3(c, v, ...) THROWF(c, v, __VA_ARGS__)
512 #define THROW4(c, v, ...) THROWF(c, v, __VA_ARGS__)
513 #define THROW5(c, v, ...) THROWF(c, v, __VA_ARGS__)
514 #define THROW6(c, v, ...) THROWF(c, v, __VA_ARGS__)
515 #define THROW7(c, v, ...) THROWF(c, v, __VA_ARGS__)
517 #define RETHROW0(...) RETHROWF(__VA_ARGS__)
518 #define RETHROW1(...) RETHROWF(__VA_ARGS__)
519 #define RETHROW2(...) RETHROWF(__VA_ARGS__)
520 #define RETHROW3(...) RETHROWF(__VA_ARGS__)
521 #define RETHROW4(...) RETHROWF(__VA_ARGS__)
522 #define RETHROW5(...) RETHROWF(__VA_ARGS__)
529 #endif /* __XBT_EX_H__ */