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Diffstat (limited to 'info/signals.c')
| -rw-r--r-- | info/signals.c | 294 |
1 files changed, 294 insertions, 0 deletions
diff --git a/info/signals.c b/info/signals.c new file mode 100644 index 0000000..0657f97 --- /dev/null +++ b/info/signals.c @@ -0,0 +1,294 @@ +/* signals.c -- install and maintain signal handlers. + $Id: signals.c,v 1.10 2007/07/01 21:20:31 karl Exp $ + + Copyright (C) 1993, 1994, 1995, 1998, 2002, 2003, 2004, 2007 + Free Software Foundation, Inc. + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. + + Originally written by Brian Fox (bfox@ai.mit.edu). */ + +#include "info.h" +#include "signals.h" + +void initialize_info_signal_handler (void); + +/* **************************************************************** */ +/* */ +/* Pretending That We Have POSIX Signals */ +/* */ +/* **************************************************************** */ + +#if !defined (HAVE_SIGPROCMASK) && defined (HAVE_SIGSETMASK) +/* Perform OPERATION on NEWSET, perhaps leaving information in OLDSET. */ +static void +sigprocmask (int operation, int *newset, int *oldset) +{ + switch (operation) + { + case SIG_UNBLOCK: + sigsetmask (sigblock (0) & ~(*newset)); + break; + + case SIG_BLOCK: + *oldset = sigblock (*newset); + break; + + case SIG_SETMASK: + sigsetmask (*newset); + break; + + default: + abort (); + } +} +#endif /* !HAVE_SIGPROCMASK && HAVE_SIGSETMASK */ + +/* **************************************************************** */ +/* */ +/* Signal Handling for Info */ +/* */ +/* **************************************************************** */ + +#if defined (HAVE_SIGACTION) || defined (HAVE_SIGPROCMASK) ||\ + defined (HAVE_SIGSETMASK) +static void +mask_termsig (sigset_t *set) +{ +# if defined (SIGTSTP) + sigaddset (set, SIGTSTP); + sigaddset (set, SIGTTOU); + sigaddset (set, SIGTTIN); +# endif +# if defined (SIGWINCH) + sigaddset (set, SIGWINCH); +# endif +#if defined (SIGQUIT) + sigaddset (set, SIGQUIT); +#endif +#if defined (SIGINT) + sigaddset (set, SIGINT); +#endif +# if defined (SIGUSR1) + sigaddset (set, SIGUSR1); +# endif +} +#endif /* HAVE_SIGACTION || HAVE_SIGPROCMASK || HAVE_SIGSETMASK */ + +static RETSIGTYPE info_signal_proc (int sig); +#if defined (HAVE_SIGACTION) +typedef struct sigaction signal_info; +signal_info info_signal_handler; + +static void +set_termsig (int sig, signal_info *old) +{ + sigaction (sig, &info_signal_handler, old); +} + +static void +restore_termsig (int sig, const signal_info *saved) +{ + sigaction (sig, saved, NULL); +} +#else /* !HAVE_SIGACTION */ +typedef RETSIGTYPE (*signal_info) (); +#define set_termsig(sig, old) (void)(*(old) = signal (sig, info_signal_proc)) +#define restore_termsig(sig, saved) (void)signal (sig, *(saved)) +#define info_signal_handler info_signal_proc +static int term_conf_busy = 0; +#endif /* !HAVE_SIGACTION */ + +static signal_info old_TSTP, old_TTOU, old_TTIN; +static signal_info old_WINCH, old_INT, old_USR1; +static signal_info old_QUIT; + +void +initialize_info_signal_handler (void) +{ +#ifdef SA_NOCLDSTOP + /* (Based on info from Paul Eggert found in coreutils.) Don't use + HAVE_SIGACTION to decide whether to use the sa_handler, sa_flags, + sa_mask members, as some systems (Solaris 7+) don't define them. Use + SA_NOCLDSTOP instead; it's been part of POSIX.1 since day 1 (in 1988). */ + info_signal_handler.sa_handler = info_signal_proc; + info_signal_handler.sa_flags = 0; + mask_termsig (&info_signal_handler.sa_mask); +#endif /* SA_NOCLDSTOP */ + +#if defined (SIGTSTP) + set_termsig (SIGTSTP, &old_TSTP); + set_termsig (SIGTTOU, &old_TTOU); + set_termsig (SIGTTIN, &old_TTIN); +#endif /* SIGTSTP */ + +#if defined (SIGWINCH) + set_termsig (SIGWINCH, &old_WINCH); +#endif + +#if defined (SIGQUIT) + set_termsig (SIGQUIT, &old_QUIT); +#endif + +#if defined (SIGINT) + set_termsig (SIGINT, &old_INT); +#endif + +#if defined (SIGUSR1) + /* Used by DJGPP to simulate SIGTSTP on Ctrl-Z. */ + set_termsig (SIGUSR1, &old_USR1); +#endif +} + +static void +redisplay_after_signal (void) +{ + terminal_clear_screen (); + display_clear_display (the_display); + window_mark_chain (windows, W_UpdateWindow); + display_update_display (windows); + display_cursor_at_point (active_window); + fflush (stdout); +} + +static void +reset_info_window_sizes (void) +{ + terminal_goto_xy (0, 0); + fflush (stdout); + terminal_unprep_terminal (); + terminal_get_screen_size (); + terminal_prep_terminal (); + display_initialize_display (screenwidth, screenheight); + window_new_screen_size (screenwidth, screenheight); + redisplay_after_signal (); +} + +static RETSIGTYPE +info_signal_proc (int sig) +{ + signal_info *old_signal_handler = NULL; + +#if !defined (HAVE_SIGACTION) + /* best effort: first increment this counter and later block signals */ + if (term_conf_busy) + return; + term_conf_busy++; +#if defined (HAVE_SIGPROCMASK) || defined (HAVE_SIGSETMASK) + { + sigset_t nvar, ovar; + sigemptyset (&nvar); + mask_termsig (&nvar); + sigprocmask (SIG_BLOCK, &nvar, &ovar); + } +#endif /* HAVE_SIGPROCMASK || HAVE_SIGSETMASK */ +#endif /* !HAVE_SIGACTION */ + switch (sig) + { +#if defined (SIGTSTP) + case SIGTSTP: + case SIGTTOU: + case SIGTTIN: +#endif +#if defined (SIGQUIT) + case SIGQUIT: +#endif +#if defined (SIGINT) + case SIGINT: +#endif + { +#if defined (SIGTSTP) + if (sig == SIGTSTP) + old_signal_handler = &old_TSTP; + if (sig == SIGTTOU) + old_signal_handler = &old_TTOU; + if (sig == SIGTTIN) + old_signal_handler = &old_TTIN; +#endif /* SIGTSTP */ +#if defined (SIGQUIT) + if (sig == SIGQUIT) + old_signal_handler = &old_QUIT; +#endif /* SIGQUIT */ +#if defined (SIGINT) + if (sig == SIGINT) + old_signal_handler = &old_INT; +#endif /* SIGINT */ + + /* For stop signals, restore the terminal IO, leave the cursor + at the bottom of the window, and stop us. */ + terminal_goto_xy (0, screenheight - 1); + terminal_clear_to_eol (); + fflush (stdout); + terminal_unprep_terminal (); + restore_termsig (sig, old_signal_handler); + UNBLOCK_SIGNAL (sig); + kill (getpid (), sig); + + /* The program is returning now. Restore our signal handler, + turn on terminal handling, redraw the screen, and place the + cursor where it belongs. */ + terminal_prep_terminal (); + set_termsig (sig, old_signal_handler); + /* window size might be changed while sleeping */ + reset_info_window_sizes (); + } + break; + +#if defined (SIGWINCH) || defined (SIGUSR1) +#ifdef SIGWINCH + case SIGWINCH: +#endif +#ifdef SIGUSR1 + case SIGUSR1: +#endif + { + /* Turn off terminal IO, tell our parent that the window has changed, + then reinitialize the terminal and rebuild our windows. */ +#ifdef SIGWINCH + if (sig == SIGWINCH) + old_signal_handler = &old_WINCH; +#endif +#ifdef SIGUSR1 + if (sig == SIGUSR1) + old_signal_handler = &old_USR1; +#endif + terminal_goto_xy (0, 0); + fflush (stdout); + terminal_unprep_terminal (); /* needless? */ + restore_termsig (sig, old_signal_handler); + UNBLOCK_SIGNAL (sig); + kill (getpid (), sig); + + /* After our old signal handler returns... */ + set_termsig (sig, old_signal_handler); /* needless? */ + terminal_prep_terminal (); + reset_info_window_sizes (); + } + break; +#endif /* SIGWINCH || SIGUSR1 */ + } +#if !defined (HAVE_SIGACTION) + /* at this time it is safer to perform unblock after decrement */ + term_conf_busy--; +#if defined (HAVE_SIGPROCMASK) || defined (HAVE_SIGSETMASK) + { + sigset_t nvar, ovar; + sigemptyset (&nvar); + mask_termsig (&nvar); + sigprocmask (SIG_UNBLOCK, &nvar, &ovar); + } +#endif /* HAVE_SIGPROCMASK || HAVE_SIGSETMASK */ +#endif /* !HAVE_SIGACTION */ +} +/* vim: set sw=2 cino={1s>2sn-s^-se-s: */ |