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/cvs/libcoro/coro.h
Revision: 1.44
Committed: Fri Dec 3 19:21:59 2010 UTC (13 years, 6 months ago) by root
Content type: text/plain
Branch: MAIN
CVS Tags: rel-5_371, rel-5_372, rel-5_37, rel-5_36
Changes since 1.43: +1 -0 lines
Log Message:
*** empty log message ***

File Contents

# Content
1 /*
2 * Copyright (c) 2001-2009 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 * This coroutine library is very much stripped down. You should either
41 * build your own process abstraction using it or - better - just use GNU
42 * Portable Threads, http://www.gnu.org/software/pth/.
43 *
44 */
45
46 /*
47 * 2006-10-26 Include stddef.h on OS X to work around one of its bugs.
48 * Reported by Michael_G_Schwern.
49 * 2006-11-26 Use _setjmp instead of setjmp on GNU/Linux.
50 * 2007-04-27 Set unwind frame info if gcc 3+ and ELF is detected.
51 * Use _setjmp instead of setjmp on _XOPEN_SOURCE >= 600.
52 * 2007-05-02 Add assembly versions for x86 and amd64 (to avoid reliance
53 * on SIGUSR2 and sigaltstack in Crossfire).
54 * 2008-01-21 Disable CFI usage on anything but GNU/Linux.
55 * 2008-03-02 Switched to 2-clause BSD license with GPL exception.
56 * 2008-04-04 New (but highly unrecommended) pthreads backend.
57 * 2008-04-24 Reinstate CORO_LOSER (had wrong stack adjustments).
58 * 2008-10-30 Support assembly method on x86 with and without frame pointer.
59 * 2008-11-03 Use a global asm statement for CORO_ASM, idea by pippijn.
60 * 2008-11-05 Hopefully fix misaligned stacks with CORO_ASM/SETJMP.
61 * 2008-11-07 rbp wasn't saved in CORO_ASM on x86_64.
62 * 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 * do not rely on makecontext passing a void * correctly.
66 * try harder to get _setjmp/_longjmp.
67 * major code cleanup/restructuring.
68 * 2008-11-10 the .cfi hacks are no longer needed.
69 * 2008-11-16 work around a freebsd pthread bug.
70 * 2008-11-19 define coro_*jmp symbols for easier porting.
71 * 2009-06-23 tentative win32-backend support for mingw32 (Yasuhiro Matsumoto).
72 * 2010-12-03 tentative support for uclibc (which lacks all sorts of things).
73 */
74
75 #ifndef CORO_H
76 #define CORO_H
77
78 #if __cplusplus
79 extern "C" {
80 #endif
81
82 #define CORO_VERSION 2
83
84 /*
85 * Changes since API version 1:
86 * replaced bogus -DCORO_LOOSE with gramatically more correct -DCORO_LOSER
87 */
88
89 /*
90 * This library consists of only three files
91 * coro.h, coro.c and LICENSE (and optionally README)
92 *
93 * It implements what is known as coroutines, in a hopefully
94 * portable way. At the moment you have to define which kind
95 * of implementation flavour you want:
96 *
97 * -DCORO_UCONTEXT
98 *
99 * This flavour uses SUSv2's get/set/swap/makecontext functions that
100 * unfortunately only newer unices support.
101 *
102 * -DCORO_SJLJ
103 *
104 * This flavour uses SUSv2's setjmp/longjmp and sigaltstack functions to
105 * do it's job. Coroutine creation is much slower than UCONTEXT, but
106 * context switching is often a bit cheaper. It should work on almost
107 * all unices.
108 *
109 * -DCORO_LINUX
110 *
111 * Old GNU/Linux systems (<= glibc-2.1) only work with this implementation
112 * (it is very fast and therefore recommended over other methods, but
113 * doesn't work with anything newer).
114 *
115 * -DCORO_LOSER
116 *
117 * Microsoft's highly proprietary platform doesn't support sigaltstack, and
118 * this automatically selects a suitable workaround for this platform.
119 * (untested)
120 *
121 * -DCORO_IRIX
122 *
123 * SGI's version of Microsoft's NT ;)
124 *
125 * -DCORO_ASM
126 *
127 * Handcoded assembly, known to work only on a few architectures/ABI:
128 * GCC + x86/IA32 and amd64/x86_64 + GNU/Linux and a few BSDs.
129 *
130 * -DCORO_PTHREAD
131 *
132 * Use the pthread API. You have to provide <pthread.h> and -lpthread.
133 * This is likely the slowest backend, and it also does not support fork(),
134 * so avoid it at all costs.
135 *
136 * If you define neither of these symbols, coro.h will try to autodetect
137 * the model. This currently works for CORO_LOSER only. For the other
138 * alternatives you should check (e.g. using autoconf) and define the
139 * following symbols: HAVE_UCONTEXT_H / HAVE_SETJMP_H / HAVE_SIGALTSTACK.
140 */
141
142 /*
143 * This is the type for the initialization function of a new coroutine.
144 */
145 typedef void (*coro_func)(void *);
146
147 /*
148 * A coroutine state is saved in the following structure. Treat it as an
149 * opaque type. errno and sigmask might be saved, but don't rely on it,
150 * implement your own switching primitive if you need that.
151 */
152 typedef struct coro_context coro_context;
153
154 /*
155 * This function creates a new coroutine. Apart from a pointer to an
156 * uninitialised coro_context, it expects a pointer to the entry function
157 * and the single pointer value that is given to it as argument.
158 *
159 * Allocating/deallocating the stack is your own responsibility.
160 *
161 * As a special case, if coro, arg, sptr and ssize are all zero,
162 * then an "empty" coro_context will be created that is suitable
163 * as an initial source for coro_transfer.
164 *
165 * This function is not reentrant, but putting a mutex around it
166 * will work.
167 */
168 void coro_create (coro_context *ctx, /* an uninitialised coro_context */
169 coro_func coro, /* the coroutine code to be executed */
170 void *arg, /* a single pointer passed to the coro */
171 void *sptr, /* start of stack area */
172 long ssize); /* size of stack area */
173
174 /*
175 * The following prototype defines the coroutine switching function. It is
176 * usually implemented as a macro, so watch out.
177 *
178 * This function is thread-safe and reentrant.
179 */
180 #if 0
181 void coro_transfer (coro_context *prev, coro_context *next);
182 #endif
183
184 /*
185 * The following prototype defines the coroutine destroy function. It is
186 * usually implemented as a macro, so watch out. It also serves
187 * no purpose unless you want to use the CORO_PTHREAD backend,
188 * where it is used to clean up the thread. You are responsible
189 * for freeing the stack and the context itself.
190 *
191 * This function is thread-safe and reentrant.
192 */
193 #if 0
194 void coro_destroy (coro_context *ctx);
195 #endif
196
197 /*
198 * That was it. No other user-visible functions are implemented here.
199 */
200
201 /*****************************************************************************/
202
203 #if !defined(CORO_LOSER) && !defined(CORO_UCONTEXT) \
204 && !defined(CORO_SJLJ) && !defined(CORO_LINUX) \
205 && !defined(CORO_IRIX) && !defined(CORO_ASM) \
206 && !defined(CORO_PTHREAD)
207 # if defined(WINDOWS)
208 # define CORO_LOSER 1 /* you don't win with windoze */
209 # elif defined(__linux) && (defined(__x86) || defined (__amd64))
210 # define CORO_ASM 1
211 # elif defined(HAVE_UCONTEXT_H)
212 # define CORO_UCONTEXT 1
213 # elif defined(HAVE_SETJMP_H) && defined(HAVE_SIGALTSTACK)
214 # define CORO_SJLJ 1
215 # else
216 error unknown or unsupported architecture
217 # endif
218 #endif
219
220 /*****************************************************************************/
221
222 #if CORO_UCONTEXT
223
224 # include <ucontext.h>
225
226 struct coro_context {
227 ucontext_t uc;
228 };
229
230 # define coro_transfer(p,n) swapcontext (&((p)->uc), &((n)->uc))
231 # define coro_destroy(ctx) (void *)(ctx)
232
233 #elif CORO_SJLJ || CORO_LOSER || CORO_LINUX || CORO_IRIX
234
235 # if defined(CORO_LINUX) && !defined(_GNU_SOURCE)
236 # define _GNU_SOURCE /* for linux libc */
237 # endif
238
239 # if !CORO_LOSER
240 # include <unistd.h>
241 # endif
242
243 /* solaris is hopelessly borked, it expands _XOPEN_UNIX to nothing */
244 # if __sun
245 # undef _XOPEN_UNIX
246 # define _XOPEN_UNIX 1
247 # endif
248
249 # include <setjmp.h>
250
251 # if _XOPEN_UNIX > 0 || defined (_setjmp)
252 # define coro_jmp_buf jmp_buf
253 # define coro_setjmp(env) _setjmp (env)
254 # define coro_longjmp(env) _longjmp ((env), 1)
255 # elif CORO_LOSER
256 # define coro_jmp_buf jmp_buf
257 # define coro_setjmp(env) setjmp (env)
258 # define coro_longjmp(env) longjmp ((env), 1)
259 # else
260 # define coro_jmp_buf sigjmp_buf
261 # define coro_setjmp(env) sigsetjmp (env, 0)
262 # define coro_longjmp(env) siglongjmp ((env), 1)
263 # endif
264
265 struct coro_context {
266 coro_jmp_buf env;
267 };
268
269 # define coro_transfer(p,n) do { if (!coro_setjmp ((p)->env)) coro_longjmp ((n)->env); } while (0)
270 # define coro_destroy(ctx) (void *)(ctx)
271
272 #elif CORO_ASM
273
274 struct coro_context {
275 void **sp; /* must be at offset 0 */
276 };
277
278 void __attribute__ ((__noinline__, __regparm__(2)))
279 coro_transfer (coro_context *prev, coro_context *next);
280
281 # define coro_destroy(ctx) (void *)(ctx)
282
283 #elif CORO_PTHREAD
284
285 # include <pthread.h>
286
287 extern pthread_mutex_t coro_mutex;
288
289 struct coro_context {
290 pthread_cond_t cv;
291 pthread_t id;
292 };
293
294 void coro_transfer (coro_context *prev, coro_context *next);
295 void coro_destroy (coro_context *ctx);
296
297 #endif
298
299 #if __cplusplus
300 }
301 #endif
302
303 #endif
304