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Diffstat (limited to 'texinfo/info/signals.c')
| -rw-r--r-- | texinfo/info/signals.c | 173 |
1 files changed, 173 insertions, 0 deletions
diff --git a/texinfo/info/signals.c b/texinfo/info/signals.c new file mode 100644 index 00000000000..a60777fe597 --- /dev/null +++ b/texinfo/info/signals.c @@ -0,0 +1,173 @@ +/* signals.c -- Install and maintain Info signal handlers. */ + +/* This file is part of GNU Info, a program for reading online documentation + stored in Info format. + + Copyright (C) 1993, 1994, 1995 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 2, 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, write to the Free Software + Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + + Written by Brian Fox (bfox@ai.mit.edu). */ + +#include "info.h" +#include "signals.h" + +/* **************************************************************** */ +/* */ +/* 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 (operation, newset, oldset) + int operation, *newset, *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 */ +/* */ +/* **************************************************************** */ + +typedef void SigHandlerType; +typedef SigHandlerType SigHandler (); + +static SigHandlerType info_signal_handler (); +static SigHandler *old_TSTP, *old_TTOU, *old_TTIN; +static SigHandler *old_WINCH, *old_INT; + +void +initialize_info_signal_handler () +{ +#if defined (SIGTSTP) + old_TSTP = (SigHandler *) signal (SIGTSTP, info_signal_handler); + old_TTOU = (SigHandler *) signal (SIGTTOU, info_signal_handler); + old_TTIN = (SigHandler *) signal (SIGTTIN, info_signal_handler); +#endif /* SIGTSTP */ + +#if defined (SIGWINCH) + old_WINCH = (SigHandler *) signal (SIGWINCH, info_signal_handler); +#endif + +#if defined (SIGINT) + old_INT = (SigHandler *) signal (SIGINT, info_signal_handler); +#endif +} + +static void +redisplay_after_signal () +{ + 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 SigHandlerType +info_signal_handler (sig) + int sig; +{ + SigHandler **old_signal_handler; + + switch (sig) + { +#if defined (SIGTSTP) + case SIGTSTP: + case SIGTTOU: + case SIGTTIN: +#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 (sig == SIGINT) + old_signal_handler = &old_INT; + + /* 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 (); + signal (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 (); + *old_signal_handler = (SigHandler *) signal (sig, info_signal_handler); + redisplay_after_signal (); + fflush (stdout); + } + break; + +#if defined (SIGWINCH) + case SIGWINCH: + { + /* Turn off terminal IO, tell our parent that the window has changed, + then reinitialize the terminal and rebuild our windows. */ + old_signal_handler = &old_WINCH; + terminal_goto_xy (0, 0); + fflush (stdout); + terminal_unprep_terminal (); + signal (sig, *old_signal_handler); + UNBLOCK_SIGNAL (sig); + kill (getpid (), sig); + + /* After our old signal handler returns... */ + terminal_get_screen_size (); + terminal_prep_terminal (); + display_initialize_display (screenwidth, screenheight); + window_new_screen_size (screenwidth, screenheight, (VFunction *)NULL); + *old_signal_handler = (SigHandler *) signal (sig, info_signal_handler); + redisplay_after_signal (); + } + break; +#endif /* SIGWINCH */ + } +} |