src/syssignal.h

   1 /* syssignal.h - System-dependent definitions for signals.
   2
   3 Copyright (C) 1993, 1999, 2001-2012 Free Software Foundation, Inc.
   4
   5 This file is part of GNU Emacs.
   6
   7 GNU Emacs is free software: you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation, either version 3 of the License, or
  10 (at your option) any later version.
  11
  12 GNU Emacs is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 extern void init_signals (void);
  21
  22 #ifdef HAVE_PTHREAD
  23 #include <pthread.h>
  24 /* If defined, asynchronous signals delivered to a non-main thread are
  25    forwarded to the main thread.  */
  26 #define FORWARD_SIGNAL_TO_MAIN_THREAD
  27 #endif
  28
  29 /* Don't #include <signal.h>.  That header should always be #included
  30    before "config.h", because some configuration files (like s/hpux.h)
  31    indicate that SIGIO doesn't work by #undef-ing SIGIO.  If this file
  32    #includes <signal.h>, then that will re-#define SIGIO and confuse
  33    things.  */
  34 /* XXX This is not correct anymore, there is a BROKEN_SIGIO macro. */
  35
  36 #define SIGMASKTYPE sigset_t
  37
  38 #define SIGEMPTYMASK (empty_mask)
  39 extern sigset_t empty_mask;
  40
  41 /* POSIX pretty much destroys any possibility of writing sigmask as a
  42    macro in standard C.  We always define our own version because the
  43    predefined macro in Glibc 2.1 is only provided for compatibility for old
  44    programs that use int as signal mask type.  */
  45 #undef sigmask
  46 #ifdef __GNUC__
  47 #define sigmask(SIG)                            \
  48   ({                                            \
  49     sigset_t _mask;                             \
  50     sigemptyset (&_mask);                       \
  51     sigaddset (&_mask, SIG);                    \
  52     _mask;                                      \
  53   })
  54 #else /* ! defined (__GNUC__) */
  55 extern sigset_t sys_sigmask ();
  56 #define sigmask(SIG) (sys_sigmask (SIG))
  57 #endif /* ! defined (__GNUC__) */
  58
  59 #undef sigpause
  60 #define sigpause(MASK)    sigsuspend (&(MASK))
  61
  62 #define sigblock(SIG)    sys_sigblock (SIG)
  63 #define sigunblock(SIG)  sys_sigunblock (SIG)
  64 #ifndef sigsetmask
  65 #define sigsetmask(SIG)  sys_sigsetmask (SIG)
  66 #endif
  67 #undef signal
  68 #define signal(SIG,ACT)      sys_signal(SIG,ACT)
  69
  70 /* Whether this is what all systems want or not, this is what
  71    appears to be assumed in the source, for example data.c:arith_error.  */
  72 typedef void (*signal_handler_t) (int);
  73
  74 signal_handler_t sys_signal (int signal_number, signal_handler_t action);
  75 sigset_t sys_sigblock   (sigset_t new_mask);
  76 sigset_t sys_sigunblock (sigset_t new_mask);
  77 sigset_t sys_sigsetmask (sigset_t new_mask);
  78 #if ! (defined TIOCNOTTY || defined USG5 || defined CYGWIN)
  79 _Noreturn void croak (char *);
  80 #endif
  81
  82 #define sys_sigdel(MASK,SIG) sigdelset (&MASK,SIG)
  83
  84 #define sigfree() sigsetmask (SIGEMPTYMASK)
  85
  86 #if defined (SIGIO) && defined (BROKEN_SIGIO)
  87 # undef SIGIO
  88 #endif
  89 /* These are only used by AIX  */
  90 #if defined (SIGPOLL) && defined (BROKEN_SIGPOLL)
  91 #undef SIGPOLL
  92 #endif
  93 #if defined (SIGAIO) && defined (BROKEN_SIGAIO)
  94 #undef SIGAIO
  95 #endif
  96 #if defined (SIGPTY) && defined (BROKEN_SIGPTY)
  97 #undef SIGPTY
  98 #endif
  99
 100
 101 /* FIXME?  Emacs only defines NSIG_MINIMUM on some platforms?  */
 102 #if NSIG < NSIG_MINIMUM
 103 # ifdef NSIG
 104 #  undef NSIG
 105 # endif
 106 # define NSIG NSIG_MINIMUM
 107 #endif
 108
 109 /* On bsd, [man says] kill does not accept a negative number to kill a pgrp.
 110    Must do that using the killpg call.  */
 111 #ifdef BSD_SYSTEM
 112 #define EMACS_KILLPG(gid, signo) (killpg ( (gid), (signo)))
 113 #else
 114 #ifdef WINDOWSNT
 115 #define EMACS_KILLPG(gid, signo) (kill (gid, signo))
 116 #else
 117 #define EMACS_KILLPG(gid, signo) (kill   (-(gid), (signo)))
 118 #endif
 119 #endif
 120
 121 /* Define SIGCHLD as an alias for SIGCLD.  There are many conditionals
 122    testing SIGCHLD.  */
 123 #ifdef SIGCLD
 124 #ifndef SIGCHLD
 125 #define SIGCHLD SIGCLD
 126 #endif /* SIGCHLD */
 127 #endif /* ! defined (SIGCLD) */
 128
 129 #ifndef HAVE_STRSIGNAL
 130 /* strsignal is in sysdep.c */
 131 char *strsignal (int);
 132 #endif
 133
 134 #ifdef FORWARD_SIGNAL_TO_MAIN_THREAD
 135 extern pthread_t main_thread;
 136 #define SIGNAL_THREAD_CHECK(signo)                                      \
 137   do {                                                                  \
 138     if (!pthread_equal (pthread_self (), main_thread))                  \
 139       {                                                                 \
 140         /* POSIX says any thread can receive the signal.  On GNU/Linux  \
 141            that is not true, but for other systems (FreeBSD at least)   \
 142            it is.  So direct the signal to the correct thread and block \
 143            it from this thread.  */                                     \
 144         sigset_t new_mask;                                              \
 145                                                                         \
 146         sigemptyset (&new_mask);                                        \
 147         sigaddset (&new_mask, signo);                                   \
 148         pthread_sigmask (SIG_BLOCK, &new_mask, 0);                      \
 149         pthread_kill (main_thread, signo);                              \
 150         return;                                                         \
 151       }                                                                 \
 152    } while (0)
 153
 154 #else /* not FORWARD_SIGNAL_TO_MAIN_THREAD */
 155 #define SIGNAL_THREAD_CHECK(signo)
 156 #endif /* not FORWARD_SIGNAL_TO_MAIN_THREAD */