1 /* Copyright (C) 1995, 1996, 1997, 1998, 1999, 2000, 2001 Free Software Foundation, Inc.
3 * This program is free software; you can redistribute it and/or modify
4 * it under the terms of the GNU General Public License as published by
5 * the Free Software Foundation; either version 2, or (at your option)
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
13 * You should have received a copy of the GNU General Public License
14 * along with this software; see the file COPYING. If not, write to
15 * the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
16 * Boston, MA 02111-1307 USA
18 * As a special exception, the Free Software Foundation gives permission
19 * for additional uses of the text contained in its release of GUILE.
21 * The exception is that, if you link the GUILE library with other files
22 * to produce an executable, this does not by itself cause the
23 * resulting executable to be covered by the GNU General Public License.
24 * Your use of that executable is in no way restricted on account of
25 * linking the GUILE library code into it.
27 * This exception does not however invalidate any other reasons why
28 * the executable file might be covered by the GNU General Public License.
30 * This exception applies only to the code released by the
31 * Free Software Foundation under the name GUILE. If you copy
32 * code from other Free Software Foundation releases into a copy of
33 * GUILE, as the General Public License permits, the exception does
34 * not apply to the code that you add in this way. To avoid misleading
35 * anyone as to the status of such modified files, you must delete
36 * this exception notice from them.
38 * If you write modifications of your own for GUILE, it is your choice
39 * whether to permit this exception to apply to your modifications.
40 * If you do not wish that, delete this exception notice. */
42 /* Software engineering face-lift by Greg J. Badros, 11-Dec-1999,
43 gjb@cs.washington.edu, http://www.cs.washington.edu/homes/gjb */
50 #include "libguile/_scm.h"
52 #include "libguile/async.h"
53 #include "libguile/eval.h"
54 #include "libguile/vectors.h"
56 #include "libguile/validate.h"
57 #include "libguile/scmsigs.h"
63 /* The thread system has its own sleep and usleep functions. */
66 #if defined(MISSING_SLEEP_DECL)
70 #if defined(HAVE_USLEEP) && defined(MISSING_USLEEP_DECL)
78 /* SIGRETTYPE is the type that signal handlers return. See <signal.h> */
81 # define SIGRETTYPE RETSIGTYPE
84 # define SIGRETTYPE void
86 # define SIGRETTYPE int
92 /* take_signal is installed as the C signal handler whenever a Scheme
93 handler is set. when a signal arrives, take_signal marks the corresponding
94 element of got_signal and marks signal_async. the thunk in signal_async
95 (sys_deliver_signals) will be run at the next opportunity, outside a
96 critical section. sys_deliver_signals runs each Scheme handler for
97 which got_signal is set. */
99 static SCM signal_async
;
101 static char got_signal
[NSIG
];
103 /* a Scheme vector of handler procedures. */
104 static SCM
*signal_handlers
;
106 /* saves the original C handlers, when a new handler is installed.
107 set to SIG_ERR if the original handler is installed. */
108 #ifdef HAVE_SIGACTION
109 static struct sigaction orig_handlers
[NSIG
];
111 static SIGRETTYPE (*orig_handlers
[NSIG
])(int);
115 take_signal (int signum
)
117 int saved_errno
= errno
;
120 if (!scm_ints_disabled
)
122 /* For reasons of speed, the SCM_NEWCELL macro doesn't defer
123 interrupts. Instead, it first sets its argument to point to
124 the first cell in the list, and then advances the freelist
125 pointer to the next cell. Now, if this procedure is
126 interrupted, the only anomalous state possible is to have
127 both SCM_NEWCELL's argument and scm_freelist pointing to the
128 same cell. To deal with this case, we always throw away the
129 first cell in scm_freelist here.
131 At least, that's the theory. I'm not convinced that that's
132 the only anomalous path we need to worry about. */
133 SCM_NEWCELL (ignored
);
135 got_signal
[signum
] = 1;
137 /* unblock the signal before the scheme handler gets to run, since
138 it may use longjmp to escape (i.e., throw an exception). */
142 sigaddset (&set
, signum
);
143 sigprocmask (SIG_UNBLOCK
, &set
, NULL
);
146 scm_system_async_mark (signal_async
);
151 sys_deliver_signals (void)
155 for (i
= 0; i
< NSIG
; i
++)
159 /* The flag is reset before calling the handler in case the
160 handler doesn't return. If the handler doesn't return
161 but leaves other signals flagged, they their handlers
162 will be applied some time later when the async is checked
163 again. It would probably be better to reset the flags
164 after doing a longjmp. */
166 #ifndef HAVE_SIGACTION
167 signal (i
, take_signal
);
169 scm_apply (SCM_VELTS (*signal_handlers
)[i
],
170 SCM_LIST1 (SCM_MAKINUM (i
)),
174 return SCM_UNSPECIFIED
;
177 /* user interface for installation of signal handlers. */
178 SCM_DEFINE (scm_sigaction
, "sigaction", 1, 2, 0,
179 (SCM signum
, SCM handler
, SCM flags
),
180 "Install or report the signal handler for a specified signal.\n\n"
181 "@var{signum} is the signal number, which can be specified using the value\n"
182 "of variables such as @code{SIGINT}.\n\n"
183 "If @var{action} is omitted, @code{sigaction} returns a pair: the\n"
184 "CAR is the current\n"
185 "signal hander, which will be either an integer with the value @code{SIG_DFL}\n"
186 "(default action) or @code{SIG_IGN} (ignore), or the Scheme procedure which\n"
187 "handles the signal, or @code{#f} if a non-Scheme procedure handles the\n"
188 "signal. The CDR contains the current @code{sigaction} flags for the handler.\n\n"
189 "If @var{action} is provided, it is installed as the new handler for\n"
190 "@var{signum}. @var{action} can be a Scheme procedure taking one\n"
191 "argument, or the value of @code{SIG_DFL} (default action) or\n"
192 "@code{SIG_IGN} (ignore), or @code{#f} to restore whatever signal handler\n"
193 "was installed before @code{sigaction} was first used. Flags can\n"
194 "optionally be specified for the new handler (@code{SA_RESTART} will\n"
195 "always be added if it's available and the system is using restartable\n"
196 "system calls.) The return value is a pair with information about the\n"
197 "old handler as described above.\n\n"
198 "This interface does not provide access to the \"signal blocking\"\n"
199 "facility. Maybe this is not needed, since the thread support may\n"
200 "provide solutions to the problem of consistent access to data\n"
202 #define FUNC_NAME s_scm_sigaction
205 #ifdef HAVE_SIGACTION
206 struct sigaction action
;
207 struct sigaction old_action
;
209 SIGRETTYPE (* chandler
) (int);
210 SIGRETTYPE (* old_chandler
) (int);
213 int save_handler
= 0;
214 SCM
*scheme_handlers
= SCM_VELTS (*signal_handlers
);
217 SCM_VALIDATE_INUM_COPY (1,signum
,csig
);
218 #if defined(HAVE_SIGACTION)
219 #if defined(SA_RESTART) && defined(HAVE_RESTARTABLE_SYSCALLS)
220 /* don't allow SA_RESTART to be omitted if HAVE_RESTARTABLE_SYSCALLS
221 is defined, since libguile would be likely to produce spurious
223 action
.sa_flags
= SA_RESTART
;
227 if (!SCM_UNBNDP (flags
))
229 SCM_VALIDATE_INUM (3,flags
);
230 action
.sa_flags
|= SCM_INUM (flags
);
232 sigemptyset (&action
.sa_mask
);
235 old_handler
= scheme_handlers
[csig
];
236 if (SCM_UNBNDP (handler
))
238 else if (SCM_EQ_P (scm_integer_p (handler
), SCM_BOOL_T
))
240 if (SCM_NUM2LONG (2,handler
) == (long) SIG_DFL
241 || SCM_NUM2LONG (2,handler
) == (long) SIG_IGN
)
243 #ifdef HAVE_SIGACTION
244 action
.sa_handler
= (SIGRETTYPE (*) (int)) SCM_INUM (handler
);
246 chandler
= (SIGRETTYPE (*) (int)) SCM_INUM (handler
);
248 scheme_handlers
[csig
] = SCM_BOOL_F
;
251 SCM_OUT_OF_RANGE (2, handler
);
253 else if (SCM_FALSEP (handler
))
255 /* restore the default handler. */
256 #ifdef HAVE_SIGACTION
257 if (orig_handlers
[csig
].sa_handler
== SIG_ERR
)
261 action
= orig_handlers
[csig
];
262 orig_handlers
[csig
].sa_handler
= SIG_ERR
;
263 scheme_handlers
[csig
] = SCM_BOOL_F
;
266 if (orig_handlers
[csig
] == SIG_ERR
)
270 chandler
= orig_handlers
[csig
];
271 orig_handlers
[csig
] = SIG_ERR
;
272 scheme_handlers
[csig
] = SCM_BOOL_F
;
278 SCM_VALIDATE_NIM (2,handler
);
279 #ifdef HAVE_SIGACTION
280 action
.sa_handler
= take_signal
;
281 if (orig_handlers
[csig
].sa_handler
== SIG_ERR
)
284 chandler
= take_signal
;
285 if (orig_handlers
[csig
] == SIG_ERR
)
288 scheme_handlers
[csig
] = handler
;
291 /* XXX - Silently ignore setting handlers for `program error signals'
292 because they can't currently be handled by Scheme code.
297 /* This list of program error signals is from the GNU Libc
304 #if defined(SIGIOT) && (SIGIOT != SIGABRT)
317 #ifdef HAVE_SIGACTION
320 if (sigaction (csig
, 0, &old_action
) == -1)
325 if (sigaction (csig
, &action
, &old_action
) == -1)
328 orig_handlers
[csig
] = old_action
;
330 if (old_action
.sa_handler
== SIG_DFL
|| old_action
.sa_handler
== SIG_IGN
)
331 old_handler
= scm_long2num ((long) old_action
.sa_handler
);
333 return scm_cons (old_handler
, SCM_MAKINUM (old_action
.sa_flags
));
337 if ((old_chandler
= signal (csig
, SIG_IGN
)) == SIG_ERR
)
339 if (signal (csig
, old_chandler
) == SIG_ERR
)
344 if ((old_chandler
= signal (csig
, chandler
)) == SIG_ERR
)
347 orig_handlers
[csig
] = old_chandler
;
349 if (old_chandler
== SIG_DFL
|| old_chandler
== SIG_IGN
)
350 old_handler
= scm_long2num ((long) old_chandler
);
352 return scm_cons (old_handler
, SCM_MAKINUM (0));
357 SCM_DEFINE (scm_restore_signals
, "restore-signals", 0, 0, 0,
359 "Return all signal handlers to the values they had before any call to\n"
360 "@code{sigaction} was made. The return value is unspecified.")
361 #define FUNC_NAME s_scm_restore_signals
364 SCM
*scheme_handlers
= SCM_VELTS (*signal_handlers
);
366 for (i
= 0; i
< NSIG
; i
++)
368 #ifdef HAVE_SIGACTION
369 if (orig_handlers
[i
].sa_handler
!= SIG_ERR
)
371 if (sigaction (i
, &orig_handlers
[i
], NULL
) == -1)
373 orig_handlers
[i
].sa_handler
= SIG_ERR
;
374 scheme_handlers
[i
] = SCM_BOOL_F
;
377 if (orig_handlers
[i
] != SIG_ERR
)
379 if (signal (i
, orig_handlers
[i
]) == SIG_ERR
)
381 orig_handlers
[i
] = SIG_ERR
;
382 scheme_handlers
[i
] = SCM_BOOL_F
;
386 return SCM_UNSPECIFIED
;
390 SCM_DEFINE (scm_alarm
, "alarm", 1, 0, 0,
392 "Set a timer to raise a @code{SIGALRM} signal after the specified\n"
393 "number of seconds (an integer). It's advisable to install a signal\n"
395 "@code{SIGALRM} beforehand, since the default action is to terminate\n"
397 "The return value indicates the time remaining for the previous alarm,\n"
398 "if any. The new value replaces the previous alarm. If there was\n"
399 "no previous alarm, the return value is zero.")
400 #define FUNC_NAME s_scm_alarm
403 SCM_VALIDATE_INUM (1,i
);
404 j
= alarm (SCM_INUM (i
));
405 return SCM_MAKINUM (j
);
410 SCM_DEFINE (scm_pause
, "pause", 0, 0, 0,
412 "Pause the current process (thread?) until a signal arrives whose\n"
413 "action is to either terminate the current process or invoke a\n"
414 "handler procedure. The return value is unspecified.")
415 #define FUNC_NAME s_scm_pause
418 return SCM_UNSPECIFIED
;
423 SCM_DEFINE (scm_sleep
, "sleep", 1, 0, 0,
425 "Wait for the given number of seconds (an integer) or until a signal\n"
426 "arrives. The return value is zero if the time elapses or the number\n"
427 "of seconds remaining otherwise.")
428 #define FUNC_NAME s_scm_sleep
431 SCM_VALIDATE_INUM_MIN (1,i
,0);
433 j
= scm_thread_sleep (SCM_INUM(i
));
435 j
= sleep (SCM_INUM(i
));
437 return scm_ulong2num (j
);
441 #if defined(USE_THREADS) || defined(HAVE_USLEEP)
442 SCM_DEFINE (scm_usleep
, "usleep", 1, 0, 0,
444 "Sleep for I microseconds. @code{usleep} is not available on\n"
446 #define FUNC_NAME s_scm_usleep
448 SCM_VALIDATE_INUM_MIN (1,i
,0);
451 /* If we have threads, we use the thread system's sleep function. */
453 unsigned long j
= scm_thread_usleep (SCM_INUM (i
));
454 return scm_ulong2num (j
);
457 #ifdef USLEEP_RETURNS_VOID
458 usleep (SCM_INUM (i
));
462 int j
= usleep (SCM_INUM (i
));
463 return SCM_MAKINUM (j
);
469 #endif /* GUILE_ISELECT || HAVE_USLEEP */
471 SCM_DEFINE (scm_raise
, "raise", 1, 0, 0,
474 "Sends a specified signal @var{sig} to the current process, where\n"
475 "@var{sig} is as described for the kill procedure.")
476 #define FUNC_NAME s_scm_raise
478 SCM_VALIDATE_INUM (1,sig
);
480 if (kill (getpid (), (int) SCM_INUM (sig
)) != 0)
483 return SCM_UNSPECIFIED
;
496 SCM_CDRLOC (scm_sysintern ("signal-handlers",
497 scm_c_make_vector (NSIG
, SCM_BOOL_F
)));
498 thunk
= scm_make_gsubr ("%deliver-signals", 0, 0, 0,
499 sys_deliver_signals
);
500 signal_async
= scm_system_async (thunk
);
502 for (i
= 0; i
< NSIG
; i
++)
505 #ifdef HAVE_SIGACTION
506 orig_handlers
[i
].sa_handler
= SIG_ERR
;
509 orig_handlers
[i
] = SIG_ERR
;
512 #ifdef HAVE_RESTARTABLE_SYSCALLS
513 /* If HAVE_RESTARTABLE_SYSCALLS is defined, it's important that
514 signals really are restartable. don't rely on the same
515 run-time that configure got: reset the default for every signal.
517 #ifdef HAVE_SIGINTERRUPT
519 #elif defined(SA_RESTART)
521 struct sigaction action
;
523 sigaction (i
, NULL
, &action
);
524 if (!(action
.sa_flags
& SA_RESTART
))
526 action
.sa_flags
|= SA_RESTART
;
527 sigaction (i
, &action
, NULL
);
531 /* if neither siginterrupt nor SA_RESTART are available we may
532 as well assume that signals are always restartable. */
536 scm_sysintern ("NSIG", scm_long2num (NSIG
));
537 scm_sysintern ("SIG_IGN", scm_long2num ((long) SIG_IGN
));
538 scm_sysintern ("SIG_DFL", scm_long2num ((long) SIG_DFL
));
540 scm_sysintern ("SA_NOCLDSTOP", scm_long2num (SA_NOCLDSTOP
));
543 scm_sysintern ("SA_RESTART", scm_long2num (SA_RESTART
));
546 #ifndef SCM_MAGIC_SNARFER
547 #include "libguile/scmsigs.x"