libcoro/coro.h

/*
 * Copyright (c) 2001-2012,2015 Marc Alexander Lehmann <schmorp@schmorp.de>
 *
 * Redistribution and use in source and binary forms, with or without modifica-
 * tion, are permitted provided that the following conditions are met:
 *
 *   1.  Redistributions of source code must retain the above copyright notice,
 *       this list of conditions and the following disclaimer.
 *
 *   2.  Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
 * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO
 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
 * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
 * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Alternatively, the contents of this file may be used under the terms of
 * the GNU General Public License ("GPL") version 2 or any later version,
 * in which case the provisions of the GPL are applicable instead of
 * the above. If you wish to allow the use of your version of this file
 * only under the terms of the GPL and not to allow others to use your
 * version of this file under the BSD license, indicate your decision
 * by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL. If you do not delete the
 * provisions above, a recipient may use your version of this file under
 * either the BSD or the GPL.
 *
 * This library is modelled strictly after Ralf S. Engelschalls article at
 * http://www.gnu.org/software/pth/rse-pmt.ps. So most of the credit must
 * go to Ralf S. Engelschall <rse@engelschall.com>.
 *
 * This coroutine library is very much stripped down. You should either
 * build your own process abstraction using it or - better - just use GNU
 * Portable Threads, http://www.gnu.org/software/pth/.
 *
 */

/*
 * 2006-10-26 Include stddef.h on OS X to work around one of its bugs.
 *            Reported by Michael_G_Schwern.
 * 2006-11-26 Use _setjmp instead of setjmp on GNU/Linux.
 * 2007-04-27 Set unwind frame info if gcc 3+ and ELF is detected.
 *            Use _setjmp instead of setjmp on _XOPEN_SOURCE >= 600.
 * 2007-05-02 Add assembly versions for x86 and amd64 (to avoid reliance
 *            on SIGUSR2 and sigaltstack in Crossfire).
 * 2008-01-21 Disable CFI usage on anything but GNU/Linux.
 * 2008-03-02 Switched to 2-clause BSD license with GPL exception.
 * 2008-04-04 New (but highly unrecommended) pthreads backend.
 * 2008-04-24 Reinstate CORO_LOSER (had wrong stack adjustments).
 * 2008-10-30 Support assembly method on x86 with and without frame pointer.
 * 2008-11-03 Use a global asm statement for CORO_ASM, idea by pippijn.
 * 2008-11-05 Hopefully fix misaligned stacks with CORO_ASM/SETJMP.
 * 2008-11-07 rbp wasn't saved in CORO_ASM on x86_64.
 *            introduce coro_destroy, which is a nop except for pthreads.
 *            speed up CORO_PTHREAD. Do no longer leak threads either.
 *            coro_create now allows one to create source coro_contexts.
 *            do not rely on makecontext passing a void * correctly.
 *            try harder to get _setjmp/_longjmp.
 *            major code cleanup/restructuring.
 * 2008-11-10 the .cfi hacks are no longer needed.
 * 2008-11-16 work around a freebsd pthread bug.
 * 2008-11-19 define coro_*jmp symbols for easier porting.
 * 2009-06-23 tentative win32-backend support for mingw32 (Yasuhiro Matsumoto).
 * 2010-12-03 tentative support for uclibc (which lacks all sorts of things).
 * 2011-05-30 set initial callee-saved-registers to zero with CORO_ASM.
 *            use .cfi_undefined rip on linux-amd64 for better backtraces.
 * 2011-06-08 maybe properly implement weird windows amd64 calling conventions.
 * 2011-07-03 rely on __GCC_HAVE_DWARF2_CFI_ASM for cfi detection.
 * 2011-08-08 cygwin trashes stacks, use pthreads with double stack on cygwin.
 * 2012-12-04 reduce misprediction penalty for x86/amd64 assembly switcher.
 * 2012-12-05 experimental fiber backend (allocates stack twice).
 * 2012-12-07 API version 3 - add coro_stack_alloc/coro_stack_free.
 * 2012-12-21 valgrind stack registering was broken.
 * 2015-12-05 experimental asm be for arm7, based on a patch by Nick Zavaritsky.
 *            use __name__ for predefined symbols, as in libecb.
 *            enable guard pages on arm, aarch64 and mips.
 * 2016-08-27 try to disable _FORTIFY_SOURCE with CORO_SJLJ, as it
 *            breaks setjmp/longjmp. Also disable CORO_ASM for asm by default,
 *            as it was reported to crash.
 * 2016-11-18 disable cfi_undefined again - backtraces might be worse, but
 *            compile compatibility is improved.
 * 2018-08-14 use a completely different pthread strategy that should allow
 *            sharing of coroutines among different threads. this would
 *            undefined behaviour before as mutexes would be unlocked on
 *            a different thread. overall, this might be slower than
 *            using a pipe for synchronisation, but pipes eat fd's...
 */

#ifndef CORO_H
#define CORO_H

#if __cplusplus
extern "C" {
#endif

/*
 * This library consists of only three files
 * coro.h, coro.c and LICENSE (and optionally README)
 *
 * It implements what is known as coroutines, in a hopefully
 * portable way.
 *
 * All compiletime symbols must be defined both when including coro.h
 * (using libcoro) as well as when compiling coro.c (the implementation).
 *
 * You can manually specify which flavour you want. If you don't define
 * any of these, libcoro tries to choose a safe and fast default:
 *
 * -DCORO_UCONTEXT
 *
 *    This flavour uses SUSv2's get/set/swap/makecontext functions that
 *    unfortunately only some unices support, and is quite slow.
 *
 * -DCORO_SJLJ
 *
 *    This flavour uses SUSv2's setjmp/longjmp and sigaltstack functions to
 *    do it's job. Coroutine creation is much slower than UCONTEXT, but
 *    context switching is a bit cheaper. It should work on almost all unices.
 *
 * -DCORO_LINUX
 *
 *    CORO_SJLJ variant.
 *    Old GNU/Linux systems (<= glibc-2.1) only work with this implementation
 *    (it is very fast and therefore recommended over other methods, but
 *    doesn't work with anything newer).
 *
 * -DCORO_LOSER
 *
 *    CORO_SJLJ variant.
 *    Microsoft's highly proprietary platform doesn't support sigaltstack, and
 *    this selects a suitable workaround for this platform. It might not work
 *    with your compiler though - it has only been tested with MSVC 6.
 *
 * -DCORO_FIBER
 *
 *    Slower, but probably more portable variant for the Microsoft operating
 *    system, using fibers. Ignores the passed stack and allocates it internally.
 *    Also, due to bugs in cygwin, this does not work with cygwin.
 *
 * -DCORO_IRIX
 *
 *    CORO_SJLJ variant.
 *    For SGI's version of Microsoft's NT ;)
 *
 * -DCORO_ASM
 *
 *    Hand coded assembly, known to work only on a few architectures/ABI:
 *    GCC + arm7/x86/IA32/amd64/x86_64 + GNU/Linux and a few BSDs. Fastest
 *    choice, if it works.
 *
 * -DCORO_PTHREAD
 *
 *    Use the pthread API. You have to provide <pthread.h> and -lpthread.
 *    This is likely the slowest backend, and it also does not support fork(),
 *    so avoid it at all costs.
 *
 * If you define neither of these symbols, coro.h will try to autodetect
 * the best/safest model. To help with the autodetection, you should check
 * (e.g. using autoconf) and define the following symbols: HAVE_UCONTEXT_H
 * / HAVE_SETJMP_H / HAVE_SIGALTSTACK.
 */

/*
 * Changes when the API changes incompatibly.
 * This is ONLY the API version - there is no ABI compatibility between releases.
 *
 * Changes in API version 2:
 * replaced bogus -DCORO_LOOSE with grammatically more correct -DCORO_LOSER
 * Changes in API version 3:
 * introduced stack management (CORO_STACKALLOC)
 */
#define CORO_VERSION 3

#include <stddef.h>

/*
 * This is the type for the initialization function of a new coroutine.
 */
typedef void (*coro_func)(void *);

/*
 * A coroutine state is saved in the following structure. Treat it as an
 * opaque type. errno and sigmask might be saved, but don't rely on it,
 * implement your own switching primitive if you need that.
 */
typedef struct coro_context coro_context;

/*
 * This function creates a new coroutine. Apart from a pointer to an
 * uninitialised coro_context, it expects a pointer to the entry function
 * and the single pointer value that is given to it as argument.
 *
 * Allocating/deallocating the stack is your own responsibility.
 *
 * As a special case, if coro, arg, sptr and ssze are all zero,
 * then an "empty" coro_context will be created that is suitable
 * as an initial source for coro_transfer.
 *
 * This function is not reentrant, but putting a mutex around it
 * will work.
 */
void coro_create (coro_context *ctx, /* an uninitialised coro_context */
                  coro_func coro,    /* the coroutine code to be executed */
                  void *arg,         /* a single pointer passed to the coro */
                  void *sptr,        /* start of stack area */
                  size_t ssze);      /* size of stack area in bytes */

/*
 * The following prototype defines the coroutine switching function. It is
 * sometimes implemented as a macro, so watch out.
 *
 * This function is thread-safe and reentrant.
 */
#if 0
void coro_transfer (coro_context *prev, coro_context *next);
#endif

/*
 * The following prototype defines the coroutine destroy function. It
 * is sometimes implemented as a macro, so watch out. It also serves no
 * purpose unless you want to use the CORO_PTHREAD backend, where it is
 * used to clean up the thread. You are responsible for freeing the stack
 * and the context itself.
 *
 * This function is thread-safe and reentrant.
 */
#if 0
void coro_destroy (coro_context *ctx);
#endif

/*****************************************************************************/
/* optional stack management                                                 */
/*****************************************************************************/
/*
 * You can disable all of the stack management functions by
 * defining CORO_STACKALLOC to 0. Otherwise, they are enabled by default.
 *
 * If stack management is enabled, you can influence the implementation via these
 * symbols:
 *
 * -DCORO_USE_VALGRIND
 *
 *    If defined, then libcoro will include valgrind/valgrind.h and register
 *    and unregister stacks with valgrind.
 *
 * -DCORO_GUARDPAGES=n
 *
 *    libcoro will try to use the specified number of guard pages to protect against
 *    stack overflow. If n is 0, then the feature will be disabled. If it isn't
 *    defined, then libcoro will choose a suitable default. If guardpages are not
 *    supported on the platform, then the feature will be silently disabled.
 */
#ifndef CORO_STACKALLOC
# define CORO_STACKALLOC 1
#endif

#if CORO_STACKALLOC

/*
 * The only allowed operations on these struct members is to read the
 * "sptr" and "ssze" members to pass it to coro_create, to read the "sptr"
 * member to see if it is false, in which case the stack isn't allocated,
 * and to set the "sptr" member to 0, to indicate to coro_stack_free to
 * not actually do anything.
 */

struct coro_stack
{
  void *sptr;
  size_t ssze;
#if CORO_USE_VALGRIND
  int valgrind_id;
#endif
};

/*
 * Try to allocate a stack of at least the given size and return true if
 * successful, or false otherwise.
 *
 * The size is *NOT* specified in bytes, but in units of sizeof (void *),
 * i.e. the stack is typically 4(8) times larger on 32 bit(64 bit) platforms
 * then the size passed in.
 *
 * If size is 0, then a "suitable" stack size is chosen (usually 1-2MB).
 */
int coro_stack_alloc (struct coro_stack *stack, unsigned int size);

/*
 * Free the stack allocated by coro_stack_alloc again. It is safe to
 * call this function on the coro_stack structure even if coro_stack_alloc
 * failed.
 */
void coro_stack_free (struct coro_stack *stack);

#endif

/*
 * That was it. No other user-serviceable parts below here.
 */

/*****************************************************************************/

#if !defined CORO_LOSER      && !defined CORO_UCONTEXT \
    && !defined CORO_SJLJ    && !defined CORO_LINUX \
    && !defined CORO_IRIX    && !defined CORO_ASM \
    && !defined CORO_PTHREAD && !defined CORO_FIBER
# if defined WINDOWS && (defined __i386__ || (__x86_64__ || defined _M_IX86 || defined _M_AMD64)
#  define CORO_ASM 1
# elif defined WINDOWS || defined _WIN32
#  define CORO_LOSER 1 /* you don't win with windoze */
# elif __linux && (__i386__ || (__x86_64__ && !__ILP32__) /*|| (__arm__ && __ARM_ARCH == 7)), not working */
#  define CORO_ASM 1
# elif defined HAVE_UCONTEXT_H
#  define CORO_UCONTEXT 1
# elif defined HAVE_SETJMP_H && defined HAVE_SIGALTSTACK
#  define CORO_SJLJ 1
# else
error unknown or unsupported architecture
# endif
#endif

/*****************************************************************************/

#if CORO_UCONTEXT

# include <ucontext.h>

struct coro_context
{
  ucontext_t uc;
};

# define coro_transfer(p,n) swapcontext (&((p)->uc), &((n)->uc))
# define coro_destroy(ctx) (void *)(ctx)

#elif CORO_SJLJ || CORO_LOSER || CORO_LINUX || CORO_IRIX

# if defined(CORO_LINUX) && !defined(_GNU_SOURCE)
#  define _GNU_SOURCE /* for glibc */
# endif

/* try to disable well-meant but buggy checks in some libcs */
# ifdef _FORTIFY_SOURCE
#  undef _FORTIFY_SOURCE
#  undef __USE_FORTIFY_LEVEL /* helps some more when too much has been included already */
# endif

# if !CORO_LOSER
#  include <unistd.h>
# endif

/* solaris is hopelessly borked, it expands _XOPEN_UNIX to nothing */
# if __sun
#  undef _XOPEN_UNIX
#  define _XOPEN_UNIX 1
# endif

# include <setjmp.h>

# if _XOPEN_UNIX > 0 || defined (_setjmp)
#  define coro_jmp_buf      jmp_buf
#  define coro_setjmp(env)  _setjmp (env)
#  define coro_longjmp(env) _longjmp ((env), 1)
# elif CORO_LOSER
#  define coro_jmp_buf      jmp_buf
#  define coro_setjmp(env)  setjmp (env)
#  define coro_longjmp(env) longjmp ((env), 1)
# else
#  define coro_jmp_buf      sigjmp_buf
#  define coro_setjmp(env)  sigsetjmp (env, 0)
#  define coro_longjmp(env) siglongjmp ((env), 1)
# endif

struct coro_context
{
  coro_jmp_buf env;
};

# define coro_transfer(p,n) do { if (!coro_setjmp ((p)->env)) coro_longjmp ((n)->env); } while (0)
# define coro_destroy(ctx) (void *)(ctx)

#elif CORO_ASM

struct coro_context
{
  void **sp; /* must be at offset 0 */
};

#if __i386__ || __x86_64__
void __attribute__ ((__noinline__, __regparm__(2)))
#else
void __attribute__ ((__noinline__))
#endif
coro_transfer (coro_context *prev, coro_context *next);

# define coro_destroy(ctx) (void *)(ctx)

#elif CORO_PTHREAD

# include <pthread.h>

extern pthread_mutex_t coro_mutex;

struct coro_context
{
  int flags;
  pthread_cond_t cv;
};

void coro_transfer (coro_context *prev, coro_context *next);
void coro_destroy (coro_context *ctx);

#elif CORO_FIBER

struct coro_context
{
  void *fiber;
  /* only used for initialisation */
  coro_func coro;
  void *arg;
};

void coro_transfer (coro_context *prev, coro_context *next);
void coro_destroy (coro_context *ctx);

#endif

#if __cplusplus
}
#endif

#endif

Revision:	1.61
Committed:	Tue Aug 14 15:46:04 2018 UTC (5 years, 9 months ago) by root
Content type:	text/plain
Branch:	MAIN
CVS Tags:	rel-6_52, rel-6_53, rel-6_54, rel-6_55, rel-6_56, rel-6_57, HEAD
Changes since 1.60:	+6 -1 lines
Log Message:	* empty log message *
#	User	Rev	Content
1	root	1.1	/*
2	root	1.55	* Copyright (c) 2001-2012,2015 Marc Alexander Lehmann <schmorp@schmorp.de>
3	root	1.51	*
4	root	1.1	* Redistribution and use in source and binary forms, with or without modifica-
5			* tion, are permitted provided that the following conditions are met:
6	root	1.51	*
7	root	1.1	* 1. Redistributions of source code must retain the above copyright notice,
8			* this list of conditions and the following disclaimer.
9	root	1.51	*
10	root	1.1	* 2. Redistributions in binary form must reproduce the above copyright
11			* notice, this list of conditions and the following disclaimer in the
12			* documentation and/or other materials provided with the distribution.
13	root	1.51	*
14	root	1.1	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
15			* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
16			* CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
17			* EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
18			* CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19			* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
20			* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
21			* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
22			* ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
23			* OF THE POSSIBILITY OF SUCH DAMAGE.
24			*
25	root	1.24	* Alternatively, the contents of this file may be used under the terms of
26			* the GNU General Public License ("GPL") version 2 or any later version,
27			* in which case the provisions of the GPL are applicable instead of
28			* the above. If you wish to allow the use of your version of this file
29			* only under the terms of the GPL and not to allow others to use your
30			* version of this file under the BSD license, indicate your decision
31			* by deleting the provisions above and replace them with the notice
32			* and other provisions required by the GPL. If you do not delete the
33			* provisions above, a recipient may use your version of this file under
34			* either the BSD or the GPL.
35			*
36	root	1.1	* This library is modelled strictly after Ralf S. Engelschalls article at
37	root	1.24	* http://www.gnu.org/software/pth/rse-pmt.ps. So most of the credit must
38	root	1.1	* go to Ralf S. Engelschall <rse@engelschall.com>.
39			*
40			* This coroutine library is very much stripped down. You should either
41	pcg	1.7	* build your own process abstraction using it or - better - just use GNU
42	root	1.1	* Portable Threads, http://www.gnu.org/software/pth/.
43	root	1.4	*
44	root	1.1	*/
45
46	root	1.14	/*
47			* 2006-10-26 Include stddef.h on OS X to work around one of its bugs.
48			* Reported by Michael_G_Schwern.
49	root	1.17	* 2006-11-26 Use _setjmp instead of setjmp on GNU/Linux.
50	root	1.20	* 2007-04-27 Set unwind frame info if gcc 3+ and ELF is detected.
51	root	1.21	* Use _setjmp instead of setjmp on _XOPEN_SOURCE >= 600.
52	root	1.22	* 2007-05-02 Add assembly versions for x86 and amd64 (to avoid reliance
53			* on SIGUSR2 and sigaltstack in Crossfire).
54	root	1.23	* 2008-01-21 Disable CFI usage on anything but GNU/Linux.
55	root	1.24	* 2008-03-02 Switched to 2-clause BSD license with GPL exception.
56	root	1.25	* 2008-04-04 New (but highly unrecommended) pthreads backend.
57	root	1.26	* 2008-04-24 Reinstate CORO_LOSER (had wrong stack adjustments).
58	root	1.28	* 2008-10-30 Support assembly method on x86 with and without frame pointer.
59	root	1.29	* 2008-11-03 Use a global asm statement for CORO_ASM, idea by pippijn.
60	root	1.30	* 2008-11-05 Hopefully fix misaligned stacks with CORO_ASM/SETJMP.
61	root	1.31	* 2008-11-07 rbp wasn't saved in CORO_ASM on x86_64.
62	root	1.32	* introduce coro_destroy, which is a nop except for pthreads.
63			* speed up CORO_PTHREAD. Do no longer leak threads either.
64			* coro_create now allows one to create source coro_contexts.
65	root	1.33	* do not rely on makecontext passing a void * correctly.
66			* try harder to get _setjmp/_longjmp.
67			* major code cleanup/restructuring.
68	root	1.37	* 2008-11-10 the .cfi hacks are no longer needed.
69	root	1.39	* 2008-11-16 work around a freebsd pthread bug.
70	root	1.40	* 2008-11-19 define coro_*jmp symbols for easier porting.
71	root	1.41	* 2009-06-23 tentative win32-backend support for mingw32 (Yasuhiro Matsumoto).
72	root	1.44	* 2010-12-03 tentative support for uclibc (which lacks all sorts of things).
73	root	1.45	* 2011-05-30 set initial callee-saved-registers to zero with CORO_ASM.
74	root	1.47	* use .cfi_undefined rip on linux-amd64 for better backtraces.
75	root	1.48	* 2011-06-08 maybe properly implement weird windows amd64 calling conventions.
76	root	1.49	* 2011-07-03 rely on __GCC_HAVE_DWARF2_CFI_ASM for cfi detection.
77	root	1.50	* 2011-08-08 cygwin trashes stacks, use pthreads with double stack on cygwin.
78	root	1.51	* 2012-12-04 reduce misprediction penalty for x86/amd64 assembly switcher.
79			* 2012-12-05 experimental fiber backend (allocates stack twice).
80	root	1.52	* 2012-12-07 API version 3 - add coro_stack_alloc/coro_stack_free.
81	root	1.54	* 2012-12-21 valgrind stack registering was broken.
82	root	1.55	* 2015-12-05 experimental asm be for arm7, based on a patch by Nick Zavaritsky.
83			* use __name__ for predefined symbols, as in libecb.
84			* enable guard pages on arm, aarch64 and mips.
85	root	1.57	* 2016-08-27 try to disable _FORTIFY_SOURCE with CORO_SJLJ, as it
86	root	1.58	* breaks setjmp/longjmp. Also disable CORO_ASM for asm by default,
87			* as it was reported to crash.
88	root	1.60	* 2016-11-18 disable cfi_undefined again - backtraces might be worse, but
89			* compile compatibility is improved.
90	root	1.61	* 2018-08-14 use a completely different pthread strategy that should allow
91			* sharing of coroutines among different threads. this would
92			* undefined behaviour before as mutexes would be unlocked on
93			* a different thread. overall, this might be slower than
94			* using a pipe for synchronisation, but pipes eat fd's...
95	root	1.14	*/
96
97	root	1.1	#ifndef CORO_H
98			#define CORO_H
99
100	root	1.43	#if __cplusplus
101			extern "C" {
102			#endif
103
104	root	1.2	/*
105			* This library consists of only three files
106	root	1.9	* coro.h, coro.c and LICENSE (and optionally README)
107	root	1.2	*
108			* It implements what is known as coroutines, in a hopefully
109	root	1.52	* portable way.
110			*
111			* All compiletime symbols must be defined both when including coro.h
112			* (using libcoro) as well as when compiling coro.c (the implementation).
113			*
114			* You can manually specify which flavour you want. If you don't define
115			* any of these, libcoro tries to choose a safe and fast default:
116	root	1.2	*
117			* -DCORO_UCONTEXT
118			*
119			* This flavour uses SUSv2's get/set/swap/makecontext functions that
120	root	1.52	* unfortunately only some unices support, and is quite slow.
121	root	1.2	*
122			* -DCORO_SJLJ
123			*
124	root	1.13	* This flavour uses SUSv2's setjmp/longjmp and sigaltstack functions to
125	root	1.2	* do it's job. Coroutine creation is much slower than UCONTEXT, but
126	root	1.52	* context switching is a bit cheaper. It should work on almost all unices.
127	root	1.3	*
128			* -DCORO_LINUX
129			*
130	root	1.52	* CORO_SJLJ variant.
131	root	1.24	* Old GNU/Linux systems (<= glibc-2.1) only work with this implementation
132			* (it is very fast and therefore recommended over other methods, but
133			* doesn't work with anything newer).
134	root	1.2	*
135	root	1.11	* -DCORO_LOSER
136	root	1.2	*
137	root	1.52	* CORO_SJLJ variant.
138	root	1.2	* Microsoft's highly proprietary platform doesn't support sigaltstack, and
139	root	1.52	* this selects a suitable workaround for this platform. It might not work
140			* with your compiler though - it has only been tested with MSVC 6.
141	root	1.2	*
142	root	1.51	* -DCORO_FIBER
143			*
144	root	1.52	* Slower, but probably more portable variant for the Microsoft operating
145			* system, using fibers. Ignores the passed stack and allocates it internally.
146			* Also, due to bugs in cygwin, this does not work with cygwin.
147	root	1.51	*
148	root	1.5	* -DCORO_IRIX
149			*
150	root	1.52	* CORO_SJLJ variant.
151			* For SGI's version of Microsoft's NT ;)
152	root	1.5	*
153	root	1.22	* -DCORO_ASM
154			*
155	root	1.52	* Hand coded assembly, known to work only on a few architectures/ABI:
156	root	1.55	* GCC + arm7/x86/IA32/amd64/x86_64 + GNU/Linux and a few BSDs. Fastest
157			* choice, if it works.
158	root	1.22	*
159	root	1.25	* -DCORO_PTHREAD
160			*
161			* Use the pthread API. You have to provide <pthread.h> and -lpthread.
162	root	1.39	* This is likely the slowest backend, and it also does not support fork(),
163			* so avoid it at all costs.
164	root	1.25	*
165	root	1.2	* If you define neither of these symbols, coro.h will try to autodetect
166	root	1.52	* the best/safest model. To help with the autodetection, you should check
167			* (e.g. using autoconf) and define the following symbols: HAVE_UCONTEXT_H
168			* / HAVE_SETJMP_H / HAVE_SIGALTSTACK.
169	root	1.2	*/
170
171			/*
172	root	1.52	* Changes when the API changes incompatibly.
173			* This is ONLY the API version - there is no ABI compatibility between releases.
174			*
175			* Changes in API version 2:
176			* replaced bogus -DCORO_LOOSE with grammatically more correct -DCORO_LOSER
177			* Changes in API version 3:
178			* introduced stack management (CORO_STACKALLOC)
179			*/
180			#define CORO_VERSION 3
181
182			#include <stddef.h>
183
184			/*
185	root	1.6	* This is the type for the initialization function of a new coroutine.
186	root	1.2	*/
187	root	1.1	typedef void (coro_func)(void );
188	root	1.2
189			/*
190	root	1.19	* A coroutine state is saved in the following structure. Treat it as an
191	root	1.2	* opaque type. errno and sigmask might be saved, but don't rely on it,
192	root	1.19	* implement your own switching primitive if you need that.
193	root	1.2	*/
194			typedef struct coro_context coro_context;
195
196			/*
197			* This function creates a new coroutine. Apart from a pointer to an
198	root	1.13	* uninitialised coro_context, it expects a pointer to the entry function
199	root	1.2	* and the single pointer value that is given to it as argument.
200			*
201	root	1.32	* Allocating/deallocating the stack is your own responsibility.
202			*
203	root	1.52	* As a special case, if coro, arg, sptr and ssze are all zero,
204	root	1.38	* then an "empty" coro_context will be created that is suitable
205	root	1.32	* as an initial source for coro_transfer.
206			*
207			* This function is not reentrant, but putting a mutex around it
208			* will work.
209	root	1.2	*/
210	root	1.19	void coro_create (coro_context ctx, / an uninitialised coro_context */
211			coro_func coro, /* the coroutine code to be executed */
212			void arg, / a single pointer passed to the coro */
213			void sptr, / start of stack area */
214	root	1.52	size_t ssze); /* size of stack area in bytes */
215	root	1.2
216			/*
217			* The following prototype defines the coroutine switching function. It is
218	root	1.52	* sometimes implemented as a macro, so watch out.
219	root	1.2	*
220	root	1.32	* This function is thread-safe and reentrant.
221	root	1.2	*/
222	root	1.32	#if 0
223			void coro_transfer (coro_context prev, coro_context next);
224			#endif
225
226			/*
227	root	1.52	* The following prototype defines the coroutine destroy function. It
228			* is sometimes implemented as a macro, so watch out. It also serves no
229			* purpose unless you want to use the CORO_PTHREAD backend, where it is
230			* used to clean up the thread. You are responsible for freeing the stack
231			* and the context itself.
232	root	1.32	*
233			* This function is thread-safe and reentrant.
234			*/
235			#if 0
236			void coro_destroy (coro_context *ctx);
237			#endif
238	root	1.2
239	root	1.52	/*****************************************************************************/
240			/* optional stack management */
241			/*****************************************************************************/
242			/*
243			* You can disable all of the stack management functions by
244			* defining CORO_STACKALLOC to 0. Otherwise, they are enabled by default.
245			*
246			* If stack management is enabled, you can influence the implementation via these
247			* symbols:
248			*
249			* -DCORO_USE_VALGRIND
250			*
251			* If defined, then libcoro will include valgrind/valgrind.h and register
252			* and unregister stacks with valgrind.
253			*
254			* -DCORO_GUARDPAGES=n
255			*
256			* libcoro will try to use the specified number of guard pages to protect against
257			* stack overflow. If n is 0, then the feature will be disabled. If it isn't
258			* defined, then libcoro will choose a suitable default. If guardpages are not
259			* supported on the platform, then the feature will be silently disabled.
260			*/
261			#ifndef CORO_STACKALLOC
262			# define CORO_STACKALLOC 1
263			#endif
264
265			#if CORO_STACKALLOC
266
267	root	1.2	/*
268	root	1.52	* The only allowed operations on these struct members is to read the
269			* "sptr" and "ssze" members to pass it to coro_create, to read the "sptr"
270			* member to see if it is false, in which case the stack isn't allocated,
271			* and to set the "sptr" member to 0, to indicate to coro_stack_free to
272			* not actually do anything.
273			*/
274
275			struct coro_stack
276			{
277			void *sptr;
278			size_t ssze;
279			#if CORO_USE_VALGRIND
280			int valgrind_id;
281			#endif
282			};
283
284			/*
285			* Try to allocate a stack of at least the given size and return true if
286			* successful, or false otherwise.
287			*
288			* The size is NOT specified in bytes, but in units of sizeof (void *),
289			* i.e. the stack is typically 4(8) times larger on 32 bit(64 bit) platforms
290			* then the size passed in.
291			*
292			* If size is 0, then a "suitable" stack size is chosen (usually 1-2MB).
293			*/
294			int coro_stack_alloc (struct coro_stack *stack, unsigned int size);
295
296			/*
297			* Free the stack allocated by coro_stack_alloc again. It is safe to
298			* call this function on the coro_stack structure even if coro_stack_alloc
299			* failed.
300			*/
301			void coro_stack_free (struct coro_stack *stack);
302
303			#endif
304
305			/*
306			* That was it. No other user-serviceable parts below here.
307	root	1.2	*/
308
309	root	1.5	/*****************************************************************************/
310
311	root	1.51	#if !defined CORO_LOSER && !defined CORO_UCONTEXT \
312			&& !defined CORO_SJLJ && !defined CORO_LINUX \
313			&& !defined CORO_IRIX && !defined CORO_ASM \
314			&& !defined CORO_PTHREAD && !defined CORO_FIBER
315	root	1.55	# if defined WINDOWS && (defined __i386__ \|\| (__x86_64__ \|\| defined _M_IX86 \|\| defined _M_AMD64)
316	root	1.51	# define CORO_ASM 1
317			# elif defined WINDOWS \|\| defined _WIN32
318	root	1.11	# define CORO_LOSER 1 /* you don't win with windoze */
319	root	1.58	# elif __linux && (__i386__ \|\| (__x86_64__ && !__ILP32__) /\|\| (__arm__ && __ARM_ARCH == 7)), not working /
320	root	1.22	# define CORO_ASM 1
321	root	1.51	# elif defined HAVE_UCONTEXT_H
322	root	1.2	# define CORO_UCONTEXT 1
323	root	1.51	# elif defined HAVE_SETJMP_H && defined HAVE_SIGALTSTACK
324	root	1.2	# define CORO_SJLJ 1
325			# else
326	root	1.1	error unknown or unsupported architecture
327	root	1.2	# endif
328	root	1.1	#endif
329
330	root	1.5	/*****************************************************************************/
331
332	root	1.1	#if CORO_UCONTEXT
333
334	root	1.22	# include <ucontext.h>
335	root	1.1
336	root	1.52	struct coro_context
337			{
338	root	1.1	ucontext_t uc;
339	root	1.2	};
340	root	1.1
341	root	1.22	# define coro_transfer(p,n) swapcontext (&((p)->uc), &((n)->uc))
342	root	1.32	# define coro_destroy(ctx) (void *)(ctx)
343	root	1.1
344	root	1.11	#elif CORO_SJLJ \|\| CORO_LOSER \|\| CORO_LINUX \|\| CORO_IRIX
345	root	1.1
346	root	1.22	# if defined(CORO_LINUX) && !defined(_GNU_SOURCE)
347	root	1.52	# define _GNU_SOURCE /* for glibc */
348	root	1.22	# endif
349	root	1.8
350	root	1.57	/* try to disable well-meant but buggy checks in some libcs */
351			# ifdef _FORTIFY_SOURCE
352			# undef _FORTIFY_SOURCE
353			# undef __USE_FORTIFY_LEVEL /* helps some more when too much has been included already */
354			# endif
355
356	root	1.33	# if !CORO_LOSER
357			# include <unistd.h>
358			# endif
359
360	root	1.36	/* solaris is hopelessly borked, it expands _XOPEN_UNIX to nothing */
361			# if __sun
362			# undef _XOPEN_UNIX
363			# define _XOPEN_UNIX 1
364			# endif
365
366	root	1.22	# include <setjmp.h>
367	root	1.1
368	root	1.40	# if _XOPEN_UNIX > 0 \|\| defined (_setjmp)
369			# define coro_jmp_buf jmp_buf
370			# define coro_setjmp(env) _setjmp (env)
371			# define coro_longjmp(env) _longjmp ((env), 1)
372	root	1.34	# elif CORO_LOSER
373	root	1.40	# define coro_jmp_buf jmp_buf
374			# define coro_setjmp(env) setjmp (env)
375			# define coro_longjmp(env) longjmp ((env), 1)
376	root	1.22	# else
377	root	1.40	# define coro_jmp_buf sigjmp_buf
378			# define coro_setjmp(env) sigsetjmp (env, 0)
379			# define coro_longjmp(env) siglongjmp ((env), 1)
380	root	1.22	# endif
381
382	root	1.52	struct coro_context
383			{
384	root	1.40	coro_jmp_buf env;
385			};
386
387			# define coro_transfer(p,n) do { if (!coro_setjmp ((p)->env)) coro_longjmp ((n)->env); } while (0)
388	root	1.32	# define coro_destroy(ctx) (void *)(ctx)
389
390	root	1.22	#elif CORO_ASM
391
392	root	1.52	struct coro_context
393			{
394	root	1.34	void *sp; / must be at offset 0 */
395	root	1.22	};
396
397	root	1.55	#if __i386__ \|\| __x86_64__
398	root	1.27	void __attribute__ ((__noinline__, __regparm__(2)))
399	root	1.55	#else
400			void __attribute__ ((__noinline__))
401			#endif
402	root	1.29	coro_transfer (coro_context prev, coro_context next);
403	root	1.25
404	root	1.32	# define coro_destroy(ctx) (void *)(ctx)
405
406	root	1.25	#elif CORO_PTHREAD
407
408	root	1.32	# include <pthread.h>
409	root	1.25
410			extern pthread_mutex_t coro_mutex;
411
412	root	1.52	struct coro_context
413			{
414	root	1.61	int flags;
415	root	1.32	pthread_cond_t cv;
416	root	1.25	};
417
418			void coro_transfer (coro_context prev, coro_context next);
419	root	1.32	void coro_destroy (coro_context *ctx);
420	root	1.1
421	root	1.51	#elif CORO_FIBER
422
423	root	1.52	struct coro_context
424			{
425	root	1.51	void *fiber;
426			/* only used for initialisation */
427			coro_func coro;
428			void *arg;
429			};
430
431	root	1.52	void coro_transfer (coro_context prev, coro_context next);
432			void coro_destroy (coro_context *ctx);
433
434	root	1.1	#endif
435
436	root	1.43	#if __cplusplus
437			}
438			#endif
439
440	root	1.1	#endif
441