/*
* Copyright (c) 2001-2012 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.
*/
#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 + x86/IA32 and 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))
# 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
# 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 */
};
void __attribute__ ((__noinline__, __regparm__(2)))
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
{
pthread_cond_t cv;
pthread_t id;
};
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