libcoro/coro.c

/*
 * Copyright (c) 2001-2011 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>.
 */

#include "coro.h"

#include <string.h>

/*****************************************************************************/
/* ucontext/setjmp/asm backends                                              */
/*****************************************************************************/
#if CORO_UCONTEXT || CORO_SJLJ || CORO_LOSER || CORO_LINUX || CORO_IRIX || CORO_ASM

# if CORO_UCONTEXT
#  include <stddef.h>
# endif

# if !defined(STACK_ADJUST_PTR)
#  if __sgi
/* IRIX is decidedly NON-unix */
#   define STACK_ADJUST_PTR(sp,ss) ((char *)(sp) + (ss) - 8)
#   define STACK_ADJUST_SIZE(sp,ss) ((ss) - 8)
#  elif (__i386__ && CORO_LINUX) || (_M_IX86 && CORO_LOSER)
#   define STACK_ADJUST_PTR(sp,ss) ((char *)(sp) + (ss))
#   define STACK_ADJUST_SIZE(sp,ss) (ss)
#  elif (__amd64__ && CORO_LINUX) || ((_M_AMD64 || _M_IA64) && CORO_LOSER)
#   define STACK_ADJUST_PTR(sp,ss) ((char *)(sp) + (ss) - 8)
#   define STACK_ADJUST_SIZE(sp,ss) (ss)
#  else
#   define STACK_ADJUST_PTR(sp,ss) (sp)
#   define STACK_ADJUST_SIZE(sp,ss) (ss)
#  endif
# endif

# include <stdlib.h>

# if CORO_SJLJ
#  include <stdio.h>
#  include <signal.h>
#  include <unistd.h>
# endif

static coro_func coro_init_func;
static void *coro_init_arg;
static coro_context *new_coro, *create_coro;

static void
coro_init (void)
{
  volatile coro_func func = coro_init_func;
  volatile void *arg = coro_init_arg;

  coro_transfer (new_coro, create_coro);

#if __linux && __amd64
  /* we blindly assume on any __linux with __amd64 we have a new enough gas with .cfi_undefined support */
  asm (".cfi_undefined rip");
#endif

  func ((void *)arg);

  /* the new coro returned. bad. just abort() for now */
  abort ();
}

# if CORO_SJLJ

static volatile int trampoline_done;

/* trampoline signal handler */
static void
trampoline (int sig)
{
  if (coro_setjmp (new_coro->env))
    coro_init (); /* start it */
  else
    trampoline_done = 1;
}

# endif

# if CORO_ASM

  asm (
       ".text\n"
       ".globl coro_transfer\n"
       ".type coro_transfer, @function\n"
       "coro_transfer:\n"
       /* windows, of course, gives a shit on the amd64 ABI and uses different registers */
       /* http://blogs.msdn.com/freik/archive/2005/03/17/398200.aspx */
       #if __amd64
         #ifdef _WIN32
           #define NUM_SAVED 8
           "\tpush %rsi\n"
           "\tpush %rdi\n"
           "\tpush %rbp\n"
           "\tpush %rbx\n"
           "\tpush %r12\n"
           "\tpush %r13\n"
           "\tpush %r14\n"
           "\tpush %r15\n"
           #if CORO_WIN_TIB
             "\tpush %gs:0x0\n"
             "\tpush %gs:0x8\n"
             "\tpush %gs:0xc\n"
           #endif
           "\tmov %rsp, (%rcx)\n"
           "\tmov (%rdx), %rsp\n"
           #if CORO_WIN_TIB
             "\tpop %gs:0xc\n"
             "\tpop %gs:0x8\n"
             "\tpop %gs:0x0\n"
           #endif
           "\tpop %r15\n"
           "\tpop %r14\n"
           "\tpop %r13\n"
           "\tpop %r12\n"
           "\tpop %rbx\n"
           "\tpop %rbp\n"
           "\tpop %rdi\n"
           "\tpop %rsi\n"
         #else
           #define NUM_SAVED 6
           "\tpush %rbp\n"
           "\tpush %rbx\n"
           "\tpush %r12\n"
           "\tpush %r13\n"
           "\tpush %r14\n"
           "\tpush %r15\n"
           "\tmov %rsp, (%rdi)\n"
           "\tmov (%rsi), %rsp\n"
           "\tpop %r15\n"
           "\tpop %r14\n"
           "\tpop %r13\n"
           "\tpop %r12\n"
           "\tpop %rbx\n"
           "\tpop %rbp\n"
         #endif
       #elif __i386
         #define NUM_SAVED 4
         "\tpush %ebp\n"
         "\tpush %ebx\n"
         "\tpush %esi\n"
         "\tpush %edi\n"
         #if CORO_WIN_TIB
           "\tpush %fs:0\n"
           "\tpush %fs:4\n"
           "\tpush %fs:8\n"
         #endif
         "\tmov %esp, (%eax)\n"
         "\tmov (%edx), %esp\n"
         #if CORO_WIN_TIB
           "\tpop %fs:8\n"
           "\tpop %fs:4\n"
           "\tpop %fs:0\n"
         #endif
         "\tpop %edi\n"
         "\tpop %esi\n"
         "\tpop %ebx\n"
         "\tpop %ebp\n"
       #else
         #error unsupported architecture
       #endif
       "\tret\n"
  );

# endif

void
coro_create (coro_context *ctx, coro_func coro, void *arg, void *sptr, long ssize)
{
  coro_context nctx;
# if CORO_SJLJ
  stack_t ostk, nstk;
  struct sigaction osa, nsa;
  sigset_t nsig, osig;
# endif

  if (!coro)
    return;

  coro_init_func = coro;
  coro_init_arg  = arg;

  new_coro    = ctx;
  create_coro = &nctx;

# if CORO_SJLJ
  /* we use SIGUSR2. first block it, then fiddle with it. */

  sigemptyset (&nsig);
  sigaddset (&nsig, SIGUSR2);
  sigprocmask (SIG_BLOCK, &nsig, &osig);

  nsa.sa_handler = trampoline;
  sigemptyset (&nsa.sa_mask);
  nsa.sa_flags = SA_ONSTACK;

  if (sigaction (SIGUSR2, &nsa, &osa))
    {
      perror ("sigaction");
      abort ();
    }

  /* set the new stack */
  nstk.ss_sp    = STACK_ADJUST_PTR (sptr, ssize); /* yes, some platforms (IRIX) get this wrong. */
  nstk.ss_size  = STACK_ADJUST_SIZE (sptr, ssize);
  nstk.ss_flags = 0;

  if (sigaltstack (&nstk, &ostk) < 0)
    {
      perror ("sigaltstack");
      abort ();
    }

  trampoline_done = 0;
  kill (getpid (), SIGUSR2);
  sigfillset (&nsig); sigdelset (&nsig, SIGUSR2);

  while (!trampoline_done)
    sigsuspend (&nsig);

  sigaltstack (0, &nstk);
  nstk.ss_flags = SS_DISABLE;
  if (sigaltstack (&nstk, 0) < 0)
    perror ("sigaltstack");

  sigaltstack (0, &nstk);
  if (~nstk.ss_flags & SS_DISABLE)
    abort ();

  if (~ostk.ss_flags & SS_DISABLE)
    sigaltstack (&ostk, 0);

  sigaction (SIGUSR2, &osa, 0);
  sigprocmask (SIG_SETMASK, &osig, 0);

# elif CORO_LOSER

  coro_setjmp (ctx->env);
  #if __CYGWIN__ && __i386
    ctx->env[8]                        = (long)    coro_init;
    ctx->env[7]                        = (long)    ((char *)sptr + ssize)         - sizeof (long);
  #elif __CYGWIN__ && __x86_64
    ctx->env[7]                        = (long)    coro_init;
    ctx->env[6]                        = (long)    ((char *)sptr + ssize)         - sizeof (long);
  #elif defined(__MINGW32__)
    ctx->env[5]                        = (long)    coro_init;
    ctx->env[4]                        = (long)    ((char *)sptr + ssize)         - sizeof (long);
  #elif defined(_M_IX86)
    ((_JUMP_BUFFER *)&ctx->env)->Eip   = (long)    coro_init;
    ((_JUMP_BUFFER *)&ctx->env)->Esp   = (long)    STACK_ADJUST_PTR (sptr, ssize) - sizeof (long);
  #elif defined(_M_AMD64)
    ((_JUMP_BUFFER *)&ctx->env)->Rip   = (__int64) coro_init;
    ((_JUMP_BUFFER *)&ctx->env)->Rsp   = (__int64) STACK_ADJUST_PTR (sptr, ssize) - sizeof (__int64);
  #elif defined(_M_IA64)
    ((_JUMP_BUFFER *)&ctx->env)->StIIP = (__int64) coro_init;
    ((_JUMP_BUFFER *)&ctx->env)->IntSp = (__int64) STACK_ADJUST_PTR (sptr, ssize) - sizeof (__int64);
  #else
    #error "microsoft libc or architecture not supported"
  #endif

# elif CORO_LINUX

  coro_setjmp (ctx->env);
  #if __GLIBC__ >= 2 && __GLIBC_MINOR__ >= 0 && defined (JB_PC) && defined (JB_SP)
    ctx->env[0].__jmpbuf[JB_PC]        = (long)    coro_init;
    ctx->env[0].__jmpbuf[JB_SP]        = (long)    STACK_ADJUST_PTR (sptr, ssize) - sizeof (long);
  #elif __GLIBC__ >= 2 && __GLIBC_MINOR__ >= 0 && defined (__mc68000__)
    ctx->env[0].__jmpbuf[0].__aregs[0] = (long int)coro_init;
    ctx->env[0].__jmpbuf[0].__sp       = (int *)   ((char *)sptr + ssize)         - sizeof (long);
  #elif defined (__GNU_LIBRARY__) && defined (__i386__)
    ctx->env[0].__jmpbuf[0].__pc       = (char *)  coro_init;
    ctx->env[0].__jmpbuf[0].__sp       = (void *)  ((char *)sptr + ssize)         - sizeof (long);
  #elif defined (__GNU_LIBRARY__) && defined (__amd64__)
    ctx->env[0].__jmpbuf[JB_PC]        = (long)    coro_init;
    ctx->env[0].__jmpbuf[0].__sp       = (void *)  ((char *)sptr + ssize)         - sizeof (long);
  #else
    #error "linux libc or architecture not supported"
  #endif

# elif CORO_IRIX

  coro_setjmp (ctx->env, 0);
  ctx->env[JB_PC]                      = (__uint64_t)coro_init;
  ctx->env[JB_SP]                      = (__uint64_t)STACK_ADJUST_PTR (sptr, ssize) - sizeof (long);

# elif CORO_ASM

  ctx->sp = (void **)(ssize + (char *)sptr);
  *--ctx->sp = (void *)abort; /* needed for alignment only */
  *--ctx->sp = (void *)coro_init;

  #if CORO_WIN_TIB
  *--ctx->sp = 0;                    /* ExceptionList */
  *--ctx->sp = (char *)sptr + ssize; /* StackBase */
  *--ctx->sp = sptr;                 /* StackLimit */
  #endif

  ctx->sp -= NUM_SAVED;
  memset (ctx->sp, 0, sizeof (*ctx->sp) * NUM_SAVED);

# elif CORO_UCONTEXT

  getcontext (&(ctx->uc));

  ctx->uc.uc_link           =  0;
  ctx->uc.uc_stack.ss_sp    = sptr;
  ctx->uc.uc_stack.ss_size  = (size_t)ssize;
  ctx->uc.uc_stack.ss_flags = 0;

  makecontext (&(ctx->uc), (void (*)())coro_init, 0);

# endif

  coro_transfer (create_coro, new_coro);
}

/*****************************************************************************/
/* pthread backend                                                           */
/*****************************************************************************/
#elif CORO_PTHREAD

/* this mutex will be locked by the running coroutine */
pthread_mutex_t coro_mutex = PTHREAD_MUTEX_INITIALIZER;

struct coro_init_args
{
  coro_func func;
  void *arg;
  coro_context *self, *main;
};

static pthread_t null_tid;

/* I'd so love to cast pthread_mutex_unlock to void (*)(void *)... */
static void
mutex_unlock_wrapper (void *arg)
{
  pthread_mutex_unlock ((pthread_mutex_t *)arg);
}

static void *
coro_init (void *args_)
{
  struct coro_init_args *args = (struct coro_init_args *)args_;
  coro_func func = args->func;
  void *arg = args->arg;

  pthread_mutex_lock (&coro_mutex);

  /* we try to be good citizens and use deferred cancellation and cleanup handlers */
  pthread_cleanup_push (mutex_unlock_wrapper, &coro_mutex);
    coro_transfer (args->self, args->main);
    func (arg);
  pthread_cleanup_pop (1);

  return 0;
}

void
coro_transfer (coro_context *prev, coro_context *next)
{
  pthread_cond_signal (&next->cv);
  pthread_cond_wait (&prev->cv, &coro_mutex);
#if __FreeBSD__ /* freebsd is of course broken and needs manual testcancel calls... yay... */
  pthread_testcancel ();
#endif
}

void
coro_create (coro_context *ctx, coro_func coro, void *arg, void *sptr, long ssize)
{
  static coro_context nctx;
  static int once;

  if (!once)
    {
      once = 1;

      pthread_mutex_lock (&coro_mutex);
      pthread_cond_init (&nctx.cv, 0);
      null_tid = pthread_self ();
    }

  pthread_cond_init (&ctx->cv, 0);

  if (coro)
    {
      pthread_attr_t attr;
      struct coro_init_args args;

      args.func = coro;
      args.arg  = arg;
      args.self = ctx;
      args.main = &nctx;

      pthread_attr_init (&attr);
#if __UCLIBC__
      /* exists, but is borked */
      /*pthread_attr_setstacksize (&attr, (size_t)ssize);*/
#else
      pthread_attr_setstack (&attr, sptr, (size_t)ssize);
#endif
      pthread_attr_setscope (&attr, PTHREAD_SCOPE_PROCESS);
      pthread_create (&ctx->id, &attr, coro_init, &args);

      coro_transfer (args.main, args.self);
    }
  else
    ctx->id = null_tid;
}

void
coro_destroy (coro_context *ctx)
{
  if (!pthread_equal (ctx->id, null_tid))
    {
      pthread_cancel (ctx->id);
      pthread_mutex_unlock (&coro_mutex);
      pthread_join (ctx->id, 0);
      pthread_mutex_lock (&coro_mutex);
    }

  pthread_cond_destroy (&ctx->cv);
}

#else
# error unsupported backend
#endif

Revision:	1.58
Committed:	Fri Jun 10 12:27:02 2011 UTC (12 years, 11 months ago) by root
Content type:	text/plain
Branch:	MAIN
Changes since 1.57:	+55 -33 lines
Log Message:	* empty log message *
#	Content
1	/*
2	* Copyright (c) 2001-2011 Marc Alexander Lehmann <schmorp@schmorp.de>
3	*
4	* Redistribution and use in source and binary forms, with or without modifica-
5	* tion, are permitted provided that the following conditions are met:
6	*
7	* 1. Redistributions of source code must retain the above copyright notice,
8	* this list of conditions and the following disclaimer.
9	*
10	* 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	*
14	* 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	* 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	* This library is modelled strictly after Ralf S. Engelschalls article at
37	* http://www.gnu.org/software/pth/rse-pmt.ps. So most of the credit must
38	* go to Ralf S. Engelschall <rse@engelschall.com>.
39	*/
40
41	#include "coro.h"
42
43	#include <string.h>
44
45	/*****************************************************************************/
46	/* ucontext/setjmp/asm backends */
47	/*****************************************************************************/
48	#if CORO_UCONTEXT \|\| CORO_SJLJ \|\| CORO_LOSER \|\| CORO_LINUX \|\| CORO_IRIX \|\| CORO_ASM
49
50	# if CORO_UCONTEXT
51	# include <stddef.h>
52	# endif
53
54	# if !defined(STACK_ADJUST_PTR)
55	# if __sgi
56	/* IRIX is decidedly NON-unix */
57	# define STACK_ADJUST_PTR(sp,ss) ((char *)(sp) + (ss) - 8)
58	# define STACK_ADJUST_SIZE(sp,ss) ((ss) - 8)
59	# elif (__i386__ && CORO_LINUX) \|\| (_M_IX86 && CORO_LOSER)
60	# define STACK_ADJUST_PTR(sp,ss) ((char *)(sp) + (ss))
61	# define STACK_ADJUST_SIZE(sp,ss) (ss)
62	# elif (__amd64__ && CORO_LINUX) \|\| ((_M_AMD64 \|\| _M_IA64) && CORO_LOSER)
63	# define STACK_ADJUST_PTR(sp,ss) ((char *)(sp) + (ss) - 8)
64	# define STACK_ADJUST_SIZE(sp,ss) (ss)
65	# else
66	# define STACK_ADJUST_PTR(sp,ss) (sp)
67	# define STACK_ADJUST_SIZE(sp,ss) (ss)
68	# endif
69	# endif
70
71	# include <stdlib.h>
72
73	# if CORO_SJLJ
74	# include <stdio.h>
75	# include <signal.h>
76	# include <unistd.h>
77	# endif
78
79	static coro_func coro_init_func;
80	static void *coro_init_arg;
81	static coro_context new_coro, create_coro;
82
83	static void
84	coro_init (void)
85	{
86	volatile coro_func func = coro_init_func;
87	volatile void *arg = coro_init_arg;
88
89	coro_transfer (new_coro, create_coro);
90
91	#if __linux && __amd64
92	/* we blindly assume on any __linux with __amd64 we have a new enough gas with .cfi_undefined support */
93	asm (".cfi_undefined rip");
94	#endif
95
96	func ((void *)arg);
97
98	/* the new coro returned. bad. just abort() for now */
99	abort ();
100	}
101
102	# if CORO_SJLJ
103
104	static volatile int trampoline_done;
105
106	/* trampoline signal handler */
107	static void
108	trampoline (int sig)
109	{
110	if (coro_setjmp (new_coro->env))
111	coro_init (); /* start it */
112	else
113	trampoline_done = 1;
114	}
115
116	# endif
117
118	# if CORO_ASM
119
120	asm (
121	".text\n"
122	".globl coro_transfer\n"
123	".type coro_transfer, @function\n"
124	"coro_transfer:\n"
125	/* windows, of course, gives a shit on the amd64 ABI and uses different registers */
126	/* http://blogs.msdn.com/freik/archive/2005/03/17/398200.aspx */
127	#if __amd64
128	#ifdef _WIN32
129	#define NUM_SAVED 8
130	"\tpush %rsi\n"
131	"\tpush %rdi\n"
132	"\tpush %rbp\n"
133	"\tpush %rbx\n"
134	"\tpush %r12\n"
135	"\tpush %r13\n"
136	"\tpush %r14\n"
137	"\tpush %r15\n"
138	#if CORO_WIN_TIB
139	"\tpush %gs:0x0\n"
140	"\tpush %gs:0x8\n"
141	"\tpush %gs:0xc\n"
142	#endif
143	"\tmov %rsp, (%rcx)\n"
144	"\tmov (%rdx), %rsp\n"
145	#if CORO_WIN_TIB
146	"\tpop %gs:0xc\n"
147	"\tpop %gs:0x8\n"
148	"\tpop %gs:0x0\n"
149	#endif
150	"\tpop %r15\n"
151	"\tpop %r14\n"
152	"\tpop %r13\n"
153	"\tpop %r12\n"
154	"\tpop %rbx\n"
155	"\tpop %rbp\n"
156	"\tpop %rdi\n"
157	"\tpop %rsi\n"
158	#else
159	#define NUM_SAVED 6
160	"\tpush %rbp\n"
161	"\tpush %rbx\n"
162	"\tpush %r12\n"
163	"\tpush %r13\n"
164	"\tpush %r14\n"
165	"\tpush %r15\n"
166	"\tmov %rsp, (%rdi)\n"
167	"\tmov (%rsi), %rsp\n"
168	"\tpop %r15\n"
169	"\tpop %r14\n"
170	"\tpop %r13\n"
171	"\tpop %r12\n"
172	"\tpop %rbx\n"
173	"\tpop %rbp\n"
174	#endif
175	#elif __i386
176	#define NUM_SAVED 4
177	"\tpush %ebp\n"
178	"\tpush %ebx\n"
179	"\tpush %esi\n"
180	"\tpush %edi\n"
181	#if CORO_WIN_TIB
182	"\tpush %fs:0\n"
183	"\tpush %fs:4\n"
184	"\tpush %fs:8\n"
185	#endif
186	"\tmov %esp, (%eax)\n"
187	"\tmov (%edx), %esp\n"
188	#if CORO_WIN_TIB
189	"\tpop %fs:8\n"
190	"\tpop %fs:4\n"
191	"\tpop %fs:0\n"
192	#endif
193	"\tpop %edi\n"
194	"\tpop %esi\n"
195	"\tpop %ebx\n"
196	"\tpop %ebp\n"
197	#else
198	#error unsupported architecture
199	#endif
200	"\tret\n"
201	);
202
203	# endif
204
205	void
206	coro_create (coro_context ctx, coro_func coro, void arg, void *sptr, long ssize)
207	{
208	coro_context nctx;
209	# if CORO_SJLJ
210	stack_t ostk, nstk;
211	struct sigaction osa, nsa;
212	sigset_t nsig, osig;
213	# endif
214
215	if (!coro)
216	return;
217
218	coro_init_func = coro;
219	coro_init_arg = arg;
220
221	new_coro = ctx;
222	create_coro = &nctx;
223
224	# if CORO_SJLJ
225	/* we use SIGUSR2. first block it, then fiddle with it. */
226
227	sigemptyset (&nsig);
228	sigaddset (&nsig, SIGUSR2);
229	sigprocmask (SIG_BLOCK, &nsig, &osig);
230
231	nsa.sa_handler = trampoline;
232	sigemptyset (&nsa.sa_mask);
233	nsa.sa_flags = SA_ONSTACK;
234
235	if (sigaction (SIGUSR2, &nsa, &osa))
236	{
237	perror ("sigaction");
238	abort ();
239	}
240
241	/* set the new stack */
242	nstk.ss_sp = STACK_ADJUST_PTR (sptr, ssize); /* yes, some platforms (IRIX) get this wrong. */
243	nstk.ss_size = STACK_ADJUST_SIZE (sptr, ssize);
244	nstk.ss_flags = 0;
245
246	if (sigaltstack (&nstk, &ostk) < 0)
247	{
248	perror ("sigaltstack");
249	abort ();
250	}
251
252	trampoline_done = 0;
253	kill (getpid (), SIGUSR2);
254	sigfillset (&nsig); sigdelset (&nsig, SIGUSR2);
255
256	while (!trampoline_done)
257	sigsuspend (&nsig);
258
259	sigaltstack (0, &nstk);
260	nstk.ss_flags = SS_DISABLE;
261	if (sigaltstack (&nstk, 0) < 0)
262	perror ("sigaltstack");
263
264	sigaltstack (0, &nstk);
265	if (~nstk.ss_flags & SS_DISABLE)
266	abort ();
267
268	if (~ostk.ss_flags & SS_DISABLE)
269	sigaltstack (&ostk, 0);
270
271	sigaction (SIGUSR2, &osa, 0);
272	sigprocmask (SIG_SETMASK, &osig, 0);
273
274	# elif CORO_LOSER
275
276	coro_setjmp (ctx->env);
277	#if __CYGWIN__ && __i386
278	ctx->env[8] = (long) coro_init;
279	ctx->env[7] = (long) ((char *)sptr + ssize) - sizeof (long);
280	#elif __CYGWIN__ && __x86_64
281	ctx->env[7] = (long) coro_init;
282	ctx->env[6] = (long) ((char *)sptr + ssize) - sizeof (long);
283	#elif defined(__MINGW32__)
284	ctx->env[5] = (long) coro_init;
285	ctx->env[4] = (long) ((char *)sptr + ssize) - sizeof (long);
286	#elif defined(_M_IX86)
287	((_JUMP_BUFFER *)&ctx->env)->Eip = (long) coro_init;
288	((_JUMP_BUFFER *)&ctx->env)->Esp = (long) STACK_ADJUST_PTR (sptr, ssize) - sizeof (long);
289	#elif defined(_M_AMD64)
290	((_JUMP_BUFFER *)&ctx->env)->Rip = (__int64) coro_init;
291	((_JUMP_BUFFER *)&ctx->env)->Rsp = (__int64) STACK_ADJUST_PTR (sptr, ssize) - sizeof (__int64);
292	#elif defined(_M_IA64)
293	((_JUMP_BUFFER *)&ctx->env)->StIIP = (__int64) coro_init;
294	((_JUMP_BUFFER *)&ctx->env)->IntSp = (__int64) STACK_ADJUST_PTR (sptr, ssize) - sizeof (__int64);
295	#else
296	#error "microsoft libc or architecture not supported"
297	#endif
298
299	# elif CORO_LINUX
300
301	coro_setjmp (ctx->env);
302	#if __GLIBC__ >= 2 && __GLIBC_MINOR__ >= 0 && defined (JB_PC) && defined (JB_SP)
303	ctx->env[0].__jmpbuf[JB_PC] = (long) coro_init;
304	ctx->env[0].__jmpbuf[JB_SP] = (long) STACK_ADJUST_PTR (sptr, ssize) - sizeof (long);
305	#elif __GLIBC__ >= 2 && __GLIBC_MINOR__ >= 0 && defined (__mc68000__)
306	ctx->env[0].__jmpbuf[0].__aregs[0] = (long int)coro_init;
307	ctx->env[0].__jmpbuf[0].__sp = (int ) ((char )sptr + ssize) - sizeof (long);
308	#elif defined (__GNU_LIBRARY__) && defined (__i386__)
309	ctx->env[0].__jmpbuf[0].__pc = (char *) coro_init;
310	ctx->env[0].__jmpbuf[0].__sp = (void ) ((char )sptr + ssize) - sizeof (long);
311	#elif defined (__GNU_LIBRARY__) && defined (__amd64__)
312	ctx->env[0].__jmpbuf[JB_PC] = (long) coro_init;
313	ctx->env[0].__jmpbuf[0].__sp = (void ) ((char )sptr + ssize) - sizeof (long);
314	#else
315	#error "linux libc or architecture not supported"
316	#endif
317
318	# elif CORO_IRIX
319
320	coro_setjmp (ctx->env, 0);
321	ctx->env[JB_PC] = (__uint64_t)coro_init;
322	ctx->env[JB_SP] = (__uint64_t)STACK_ADJUST_PTR (sptr, ssize) - sizeof (long);
323
324	# elif CORO_ASM
325
326	ctx->sp = (void *)(ssize + (char )sptr);
327	--ctx->sp = (void )abort; /* needed for alignment only */
328	--ctx->sp = (void )coro_init;
329
330	#if CORO_WIN_TIB
331	--ctx->sp = 0; / ExceptionList */
332	--ctx->sp = (char )sptr + ssize; /* StackBase */
333	--ctx->sp = sptr; / StackLimit */
334	#endif
335
336	ctx->sp -= NUM_SAVED;
337	memset (ctx->sp, 0, sizeof (ctx->sp) NUM_SAVED);
338
339	# elif CORO_UCONTEXT
340
341	getcontext (&(ctx->uc));
342
343	ctx->uc.uc_link = 0;
344	ctx->uc.uc_stack.ss_sp = sptr;
345	ctx->uc.uc_stack.ss_size = (size_t)ssize;
346	ctx->uc.uc_stack.ss_flags = 0;
347
348	makecontext (&(ctx->uc), (void (*)())coro_init, 0);
349
350	# endif
351
352	coro_transfer (create_coro, new_coro);
353	}
354
355	/*****************************************************************************/
356	/* pthread backend */
357	/*****************************************************************************/
358	#elif CORO_PTHREAD
359
360	/* this mutex will be locked by the running coroutine */
361	pthread_mutex_t coro_mutex = PTHREAD_MUTEX_INITIALIZER;
362
363	struct coro_init_args
364	{
365	coro_func func;
366	void *arg;
367	coro_context self, main;
368	};
369
370	static pthread_t null_tid;
371
372	/* I'd so love to cast pthread_mutex_unlock to void ()(void )... */
373	static void
374	mutex_unlock_wrapper (void *arg)
375	{
376	pthread_mutex_unlock ((pthread_mutex_t *)arg);
377	}
378
379	static void *
380	coro_init (void *args_)
381	{
382	struct coro_init_args args = (struct coro_init_args )args_;
383	coro_func func = args->func;
384	void *arg = args->arg;
385
386	pthread_mutex_lock (&coro_mutex);
387
388	/* we try to be good citizens and use deferred cancellation and cleanup handlers */
389	pthread_cleanup_push (mutex_unlock_wrapper, &coro_mutex);
390	coro_transfer (args->self, args->main);
391	func (arg);
392	pthread_cleanup_pop (1);
393
394	return 0;
395	}
396
397	void
398	coro_transfer (coro_context prev, coro_context next)
399	{
400	pthread_cond_signal (&next->cv);
401	pthread_cond_wait (&prev->cv, &coro_mutex);
402	#if __FreeBSD__ /* freebsd is of course broken and needs manual testcancel calls... yay... */
403	pthread_testcancel ();
404	#endif
405	}
406
407	void
408	coro_create (coro_context ctx, coro_func coro, void arg, void *sptr, long ssize)
409	{
410	static coro_context nctx;
411	static int once;
412
413	if (!once)
414	{
415	once = 1;
416
417	pthread_mutex_lock (&coro_mutex);
418	pthread_cond_init (&nctx.cv, 0);
419	null_tid = pthread_self ();
420	}
421
422	pthread_cond_init (&ctx->cv, 0);
423
424	if (coro)
425	{
426	pthread_attr_t attr;
427	struct coro_init_args args;
428
429	args.func = coro;
430	args.arg = arg;
431	args.self = ctx;
432	args.main = &nctx;
433
434	pthread_attr_init (&attr);
435	#if __UCLIBC__
436	/* exists, but is borked */
437	/pthread_attr_setstacksize (&attr, (size_t)ssize);/
438	#else
439	pthread_attr_setstack (&attr, sptr, (size_t)ssize);
440	#endif
441	pthread_attr_setscope (&attr, PTHREAD_SCOPE_PROCESS);
442	pthread_create (&ctx->id, &attr, coro_init, &args);
443
444	coro_transfer (args.main, args.self);
445	}
446	else
447	ctx->id = null_tid;
448	}
449
450	void
451	coro_destroy (coro_context *ctx)
452	{
453	if (!pthread_equal (ctx->id, null_tid))
454	{
455	pthread_cancel (ctx->id);
456	pthread_mutex_unlock (&coro_mutex);
457	pthread_join (ctx->id, 0);
458	pthread_mutex_lock (&coro_mutex);
459	}
460
461	pthread_cond_destroy (&ctx->cv);
462	}
463
464	#else
465	# error unsupported backend
466	#endif
467