libcoro/coro.c

/*
 * Copyright (c) 2001 Marc Alexander Lehmann <pcg@goof.com>
 * 
 * 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.
 * 
 *   3.  The name of the author may not be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 * 
 * 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.
 *
 * 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"

#if CORO_LOOSE || CORO_SJLJ

#include <signal.h>

static volatile coro_func coro_init_func;
static volatile void *coro_init_arg;
static volatile 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);

  func (arg);

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

# if CORO_SJLJ
# define coro_save(ctx)     (void)setjmp((ctx)->env)

static volatile int trampoline_count;

/* trampoline signal handler */
static void
trampoline(int sig)
{
  if (setjmp (&(new_coro->env)))
    coro_init (); /* start it */
  else
    trampoline_count++;
}

# endif

#elif CORO_UCONTEXT
# define coro_save(ctx)     getcontext(&((ctx)->uc))
#endif

/* initialize a machine state */
void coro_create(coro_context *ctx,
                 coro_func coro, void *arg,
                 void *sptr, long ssize)
{
#if 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, 1, arg);

#elif CORO_SJLJ || CORO_LOOSE

# if CORO_SJLJ
  stack_t ostk, nstk;
  struct sigaction osa, nsa;
  sigset_t nsig, osig;
# endif
  coro_context nctx;

  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");

  /* set the new stack */
  nstk.ss_sp    = sptr;
  nstk.ss_size  = ssize;
  nstk.ss_flags = 0;

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

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

  while (!trampoline_count)
    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 (SIGUSR1, &osa, 0);

  sigprocmask (SIG_SETMASK, &osig, 0);

# elif MS_LOOSE

  coro_save (ctx);
  ctx->env[7] = (int)((char *)sptr + ssize);
  ctx->env[8] = (int)coro;

# endif

  coro_transfer (create_coro, new_coro);

#else
error unsupported architecture
#endif
}

Revision:	1.1
Committed:	Mon Jul 23 17:13:08 2001 UTC (25 years, 1 month ago) by root
Content type:	text/plain
Branch:	MAIN
Log Message:	* empty log message *
#	User	Rev	Content
1	root	1.1	/*
2			* Copyright (c) 2001 Marc Alexander Lehmann <pcg@goof.com>
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			* 3. The name of the author may not be used to endorse or promote products
15			* derived from this software without specific prior written permission.
16			*
17			* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
18			* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
19			* CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
20			* EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
21			* CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
22			* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
23			* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
24			* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
25			* ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
26			* OF THE POSSIBILITY OF SUCH DAMAGE.
27			*
28			* This library is modelled strictly after Ralf S. Engelschalls article at
29			* http://www.gnu.org/software/pth/rse-pmt.ps. So most of the credit must
30			* go to Ralf S. Engelschall <rse@engelschall.com>.
31			*/
32
33			#include "coro.h"
34
35			#if CORO_LOOSE \|\| CORO_SJLJ
36
37			#include <signal.h>
38
39			static volatile coro_func coro_init_func;
40			static volatile void *coro_init_arg;
41			static volatile coro_context new_coro, create_coro;
42
43			static void
44			coro_init (void)
45			{
46			volatile coro_func func = coro_init_func;
47			volatile void *arg = coro_init_arg;
48
49			coro_transfer (new_coro, create_coro);
50
51			func (arg);
52
53			/* the new coro returned. bad. just abort() for now */
54			abort ();
55			}
56
57			# if CORO_SJLJ
58			# define coro_save(ctx) (void)setjmp((ctx)->env)
59
60			static volatile int trampoline_count;
61
62			/* trampoline signal handler */
63			static void
64			trampoline(int sig)
65			{
66			if (setjmp (&(new_coro->env)))
67			coro_init (); /* start it */
68			else
69			trampoline_count++;
70			}
71
72			# endif
73
74			#elif CORO_UCONTEXT
75			# define coro_save(ctx) getcontext(&((ctx)->uc))
76			#endif
77
78			/* initialize a machine state */
79			void coro_create(coro_context *ctx,
80			coro_func coro, void *arg,
81			void *sptr, long ssize)
82			{
83			#if CORO_UCONTEXT
84
85			getcontext (&(ctx->uc));
86
87			ctx->uc.uc_link = 0;
88			ctx->uc.uc_stack.ss_sp = sptr;
89			ctx->uc.uc_stack.ss_size = (size_t) ssize;
90			ctx->uc.uc_stack.ss_flags = 0;
91
92			makecontext (&(ctx->uc), (void (*)()) coro, 1, arg);
93
94			#elif CORO_SJLJ \|\| CORO_LOOSE
95
96			# if CORO_SJLJ
97			stack_t ostk, nstk;
98			struct sigaction osa, nsa;
99			sigset_t nsig, osig;
100			# endif
101			coro_context nctx;
102
103			coro_init_func = coro;
104			coro_init_arg = arg;
105
106			new_coro = ctx;
107			create_coro = &nctx;
108
109			# if CORO_SJLJ
110			/* we use SIGUSR2. first block it, then fiddle with it. */
111
112			sigemptyset (&nsig);
113			sigaddset (&nsig, SIGUSR2);
114			sigprocmask (SIG_BLOCK, &nsig, &osig);
115
116			nsa.sa_handler = trampoline;
117			sigemptyset (&nsa.sa_mask);
118			nsa.sa_flags = SA_ONSTACK;
119
120			if (sigaction (SIGUSR2, &nsa, &osa))
121			perror ("sigaction");
122
123			/* set the new stack */
124			nstk.ss_sp = sptr;
125			nstk.ss_size = ssize;
126			nstk.ss_flags = 0;
127
128			if (sigaltstack (&nstk, &ostk) < 0)
129			perror ("sigaltstack");
130
131			trampoline_count = 0;
132			kill (getpid (), SIGUSR2);
133			sigfillset (&nsig); sigdelset (&nsig, SIGUSR2);
134
135			while (!trampoline_count)
136			sigsuspend (&nsig);
137
138			sigaltstack (0, &nstk);
139			nstk.ss_flags = SS_DISABLE;
140			if (sigaltstack (&nstk, 0) < 0)
141			perror ("sigaltstack");
142
143			sigaltstack (0, &nstk);
144			if (~nstk.ss_flags & SS_DISABLE)
145			abort ();
146
147			if (~ostk.ss_flags & SS_DISABLE)
148			sigaltstack (&ostk, 0);
149
150			sigaction (SIGUSR1, &osa, 0);
151
152			sigprocmask (SIG_SETMASK, &osig, 0);
153
154			# elif MS_LOOSE
155
156			coro_save (ctx);
157			ctx->env[7] = (int)((char *)sptr + ssize);
158			ctx->env[8] = (int)coro;
159
160			# endif
161
162			coro_transfer (create_coro, new_coro);
163
164			#else
165			error unsupported architecture
166			#endif
167			}
168