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comparison src/syssignal.h @ 0:376386a54a3c r19-14

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Import from CVS: tag r19-14
author cvs
date Mon, 13 Aug 2007 08:45:50 +0200
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1 /* syssignal.h - System-dependent definitions for signals.
2 Copyright (C) 1992, 1993 Free Software Foundation, Inc.
3
4 This file is part of XEmacs.
5
6 XEmacs is free software; you can redistribute it and/or modify it
7 under the terms of the GNU General Public License as published by the
8 Free Software Foundation; either version 2, or (at your option) any
9 later version.
10
11 XEmacs is distributed in the hope that it will be useful, but WITHOUT
12 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with XEmacs; see the file COPYING. If not, write to
18 the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
19 Boston, MA 02111-1307, USA. */
20
21 /* Synched up with: FSF 19.30. */
22
23 #ifndef _XEMACS_SYSSIGNAL_H_
24 #define _XEMACS_SYSSIGNAL_H_
25
26 /* In the old world, one could not #include <signal.h> here. The party line
27 was that that header should always be #included before <config.h>, because
28 some configuration files (like s/hpux.h) indicate that SIGIO doesn't work
29 by #undef-ing SIGIO, and if this file #includes <signal.h>, then that will
30 re-#define SIGIO and confuse things.
31
32 This was, however, a completely fucked up state of affairs, because on some
33 systems it's necessary for the s/m files to #define things in order to get
34 <signal.h> to provide the right typedefs, etc. And it's generally a broken
35 concept for <config.h> to not be the very very first file included.
36
37 So instead of #undef'ing SIGIO in the various s/m files, I've changed them
38 to define BROKEN_SIGIO instead, then we (syssignal.h) do an #undef SIGIO
39 at the end, after including signal.h. Therefore, it's important that
40 <signal.h> not be included after "syssignal.h", but that's the normal state:
41 nothing should be directly including <signal.h> these days.
42 -- jwz, 29-nov-93
43 */
44
45 #include <signal.h>
46 #include <errno.h>
47
48 /* SIGPOLL is the SVR4 signal. Those systems generally define
49 SIGIO as an alias for SIGPOLL, but just in case ... */
50
51 #if !defined (SIGIO) && defined (SIGPOLL)
52 # define SIGIO SIGPOLL
53 #endif
54
55 #if defined (BROKEN_SIGIO)
56 # undef SIGIO
57 #endif
58
59 /* Define SIGCHLD as an alias for SIGCLD. There are many conditionals
60 testing SIGCHLD. */
61 #if !defined (VMS) && defined (SIGCLD) && !defined (SIGCHLD)
62 # define SIGCHLD SIGCLD
63 #endif /* SIGCHLD */
64
65 #ifdef BROKEN_SIGCHLD
66 #undef SIGCHLD
67 #endif
68
69 #ifdef SIGCHLD
70 #define EMACS_BLOCK_SIGCHLD EMACS_BLOCK_SIGNAL (SIGCHLD)
71 #define EMACS_UNBLOCK_SIGCHLD EMACS_UNBLOCK_SIGNAL (SIGCHLD)
72 #else
73 #define EMACS_BLOCK_SIGCHLD
74 #define EMACS_UNBLOCK_SIGCHLD
75 #endif
76
77 /* According to W.R. Stevens __Advanced Programming in the Unix
78 Environment__, there are four different paradigms for handling
79 signals. We use autoconf to tell us which one applies.
80
81 Note that on some systems, more than one paradigm is implemented
82 (typically, the POSIX sigaction/sigprocmask and either the older
83 SYSV or BSD way). In such a case, we prefer the POSIX way.
84
85 NOTE: We use EMACS_* macros for most signal operations, but
86 just signal() for the standard signal-setting operation.
87 Perhaps we should change this to EMACS_SIGNAL(), but that runs
88 the risk of someone forgetting this convention and calling
89 signal() directly. */
90
91 #if defined (HAVE_SIGPROCMASK)
92
93 /* The POSIX way (sigaction, sigprocmask, sigpending, sigsuspend) */
94
95 typedef SIGTYPE (*signal_handler_t) (int);
96 extern signal_handler_t sys_do_signal (int signal_number,
97 signal_handler_t action);
98 /* Provide our own version of signal(), that calls sigaction(). The
99 name is not sys_signal() because a function of that name exists in
100 libenergize.a */
101 #undef signal
102 #define signal sys_do_signal
103
104 #define EMACS_BLOCK_SIGNAL(sig) do \
105 { \
106 sigset_t _mask; \
107 sigemptyset (&_mask); \
108 sigaddset (&_mask, sig); \
109 sigprocmask (SIG_BLOCK, &_mask, NULL); \
110 } while (0)
111 #define EMACS_UNBLOCK_SIGNAL(sig) do \
112 { \
113 sigset_t _mask; \
114 sigemptyset (&_mask); \
115 sigaddset (&_mask, sig); \
116 sigprocmask (SIG_UNBLOCK, &_mask, NULL); \
117 } while (0)
118 #define EMACS_UNBLOCK_ALL_SIGNALS() do \
119 { \
120 sigset_t _mask; \
121 sigemptyset (&_mask); \
122 sigprocmask (SIG_SETMASK, &_mask, NULL); \
123 } while (0)
124 #define EMACS_WAIT_FOR_SIGNAL(sig) do \
125 { \
126 sigset_t _mask; \
127 sigprocmask (0, NULL, &_mask); \
128 sigdelset (&_mask, sig); \
129 sigsuspend (&_mask); \
130 } while (0)
131 #define EMACS_REESTABLISH_SIGNAL(sig, handler)
132
133 #elif defined (HAVE_SIGBLOCK)
134
135 /* The older BSD way (signal/sigvec, sigblock, sigsetmask, sigpause) */
136
137 /* It's OK to use signal() here directly. No unreliable signal
138 problems. However, we use sigvec() because it allows us to
139 request interruptible I/O. */
140
141 #define signal sys_do_signal
142
143 /* Is it necessary to define sigmask like this? */
144 #ifndef sigmask
145 # define sigmask(no) (1L << ((no) - 1))
146 #endif
147
148 #define EMACS_BLOCK_SIGNAL(sig) sigblock (sigmask (sig))
149 #define EMACS_UNBLOCK_SIGNAL(sig) sigsetmask (sigblock (0) & ~sigmask (sig))
150 #define EMACS_UNBLOCK_ALL_SIGNALS() sigsetmask (0)
151 #define EMACS_WAIT_FOR_SIGNAL(sig) do \
152 { \
153 int _mask = sigblock (0); \
154 sigpause (_mask & ~sigmask (sig)); \
155 } while (0)
156 #define EMACS_REESTABLISH_SIGNAL(sig, handler)
157
158 #elif defined (HAVE_SIGHOLD)
159
160 /* The older SYSV way (signal/sigset, sighold, sigrelse, sigignore,
161 sigpause) */
162
163 #define signal sigset
164 #define EMACS_BLOCK_SIGNAL(sig) sighold (sig)
165 #define EMACS_UNBLOCK_SIGNAL(sig) sigrelse (sig)
166 /* #### There's not really any simple way to implement this.
167 Since EMACS_UNBLOCK_ALL_SIGNALS() is only called once (at startup),
168 it's probably OK to just ignore it. */
169 #define EMACS_UNBLOCK_ALL_SIGNALS() 0
170 #define EMACS_WAIT_FOR_SIGNAL(sig) sigpause (sig)
171 #define EMACS_REESTABLISH_SIGNAL(sig, handler)
172
173 #else
174
175 /* The oldest SYSV way (signal only; unreliable signals) */
176
177 /* Old USG systems don't really have signal blocking.
178 We indicate this by not defining EMACS_BLOCK_SIGNAL or
179 EMACS_WAIT_FOR_SIGNAL. */
180 #define EMACS_UNBLOCK_SIGNAL(sig) 0
181 #define EMACS_UNBLOCK_ALL_SIGNALS() 0
182 #define EMACS_REESTABLISH_SIGNAL(sig, handler) do \
183 { \
184 int old_errno = errno; \
185 signal (sig, handler); \
186 errno = old_errno; \
187 } while (0)
188
189 /* Under SYSV, setting a signal handler for SIGCLD causes
190 SIGCLD to immediately be sent if there any unwaited processes
191 out there. This means that the SIGCLD handler *must* call
192 wait() to reap the status of all processes -- it cannot
193 simply set a flag and then reestablish the handler, because
194 it will get called again, infinitely. We only need to
195 worry about this on systems where signals need to be
196 reestablished (SYSV Release 2 and earlier). */
197 #define OBNOXIOUS_SYSV_SIGCLD_BEHAVIOR
198
199 #endif
200
201 /* On bsd, [man says] kill does not accept a negative number to kill a pgrp.
202 Must do that using the killpg call. */
203 #ifdef BSD
204 #define EMACS_KILLPG(gid, signo) killpg (gid, signo)
205 #else
206 #ifdef WINDOWSNT
207 #define EMACS_KILLPG(gid, signo) (win32_kill_process (gid, signo))
208 #else
209 #define EMACS_KILLPG(gid, signo) kill (-(gid), signo)
210 #endif
211 #endif
212
213 #ifdef VMS
214 # define sys_siglist sys_errlist
215 # define NSIG sys_nerr
216 #endif /* VMS */
217
218 #ifndef NSIG
219 # define NSIG (SIGUSR2+1) /* guess how many elements are in sys_siglist... */
220 #endif
221
222 /* SYS_SIGLIST_DECLARED is determined by configure. On Linux, it seems,
223 configure incorrectly fails to find it, so s/linux.h defines
224 HAVE_SYS_SIGLIST. */
225 #if !defined (SYS_SIGLIST_DECLARED) && !defined (HAVE_SYS_SIGLIST)
226 extern CONST char *sys_siglist[];
227 #endif
228
229 #ifdef SIGDANGER
230 extern SIGTYPE memory_warning_signal (int sig);
231 #endif
232
233 #endif /* _XEMACS_SYSSIGNAL_H_ */