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author | Rong-En Fan <rafan@FreeBSD.org> | 2008-11-09 09:06:04 +0000 |
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committer | Rong-En Fan <rafan@FreeBSD.org> | 2008-11-09 09:06:04 +0000 |
commit | a388f199193767bacbb38b172ab89cb84369736c (patch) | |
tree | a1816f5667d2280b970ca44e407bac8cc4496c0a /ncurses/tty/lib_tstp.c | |
parent | aa59d4d4c5dda7e1c6f9dc0cc6edc58992a525c7 (diff) | |
download | src-a388f199193767bacbb38b172ab89cb84369736c.tar.gz src-a388f199193767bacbb38b172ab89cb84369736c.zip |
- Flatten the vendor area
Notes
Notes:
svn path=/vendor/ncurses/dist/; revision=184786
Diffstat (limited to 'ncurses/tty/lib_tstp.c')
-rw-r--r-- | ncurses/tty/lib_tstp.c | 389 |
1 files changed, 389 insertions, 0 deletions
diff --git a/ncurses/tty/lib_tstp.c b/ncurses/tty/lib_tstp.c new file mode 100644 index 000000000000..06c8411caa4d --- /dev/null +++ b/ncurses/tty/lib_tstp.c @@ -0,0 +1,389 @@ +/**************************************************************************** + * Copyright (c) 1998-2007,2008 Free Software Foundation, Inc. * + * * + * Permission is hereby granted, free of charge, to any person obtaining a * + * copy of this software and associated documentation files (the * + * "Software"), to deal in the Software without restriction, including * + * without limitation the rights to use, copy, modify, merge, publish, * + * distribute, distribute with modifications, sublicense, and/or sell * + * copies of the Software, and to permit persons to whom the Software is * + * furnished to do so, subject to the following conditions: * + * * + * The above copyright notice and this permission notice shall be included * + * in all copies or substantial portions of the Software. * + * * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS * + * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF * + * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. * + * IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, * + * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR * + * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR * + * THE USE OR OTHER DEALINGS IN THE SOFTWARE. * + * * + * Except as contained in this notice, the name(s) of the above copyright * + * holders shall not be used in advertising or otherwise to promote the * + * sale, use or other dealings in this Software without prior written * + * authorization. * + ****************************************************************************/ + +/**************************************************************************** + * Author: Zeyd M. Ben-Halim <zmbenhal@netcom.com> 1992,1995 * + * and: Eric S. Raymond <esr@snark.thyrsus.com> * + * and: Thomas E. Dickey 1995-on * + ****************************************************************************/ + +/* +** lib_tstp.c +** +** The routine _nc_signal_handler(). +** +*/ +#include <curses.priv.h> + +#include <SigAction.h> + +#if SVR4_ACTION && !defined(_POSIX_SOURCE) +#define _POSIX_SOURCE +#endif + +MODULE_ID("$Id: lib_tstp.c,v 1.37 2008/05/03 16:24:56 tom Exp $") + +#if defined(SIGTSTP) && (HAVE_SIGACTION || HAVE_SIGVEC) +#define USE_SIGTSTP 1 +#else +#define USE_SIGTSTP 0 +#endif + +#ifdef TRACE +static const char * +signal_name(int sig) +{ + switch (sig) { + case SIGALRM: + return "SIGALRM"; +#ifdef SIGCONT + case SIGCONT: + return "SIGCONT"; +#endif + case SIGINT: + return "SIGINT"; + case SIGQUIT: + return "SIGQUIT"; + case SIGTERM: + return "SIGTERM"; +#ifdef SIGTSTP + case SIGTSTP: + return "SIGTSTP"; +#endif +#ifdef SIGTTOU + case SIGTTOU: + return "SIGTTOU"; +#endif +#ifdef SIGWINCH + case SIGWINCH: + return "SIGWINCH"; +#endif + default: + return "unknown signal"; + } +} +#endif + +/* + * Note: This code is fragile! Its problem is that different OSs + * handle restart of system calls interrupted by signals differently. + * The ncurses code needs signal-call restart to happen -- otherwise, + * interrupted wgetch() calls will return FAIL, probably making the + * application think the input stream has ended and it should + * terminate. In particular, you know you have this problem if, when + * you suspend an ncurses-using lynx with ^Z and resume, it dies + * immediately. + * + * Default behavior of POSIX sigaction(2) is not to restart + * interrupted system calls, but Linux's sigaction does it anyway (at + * least, on and after the 1.1.47 I (esr) use). Thus this code works + * OK under Linux. The 4.4BSD sigaction(2) supports a (non-portable) + * SA_RESTART flag that forces the right behavior. Thus, this code + * should work OK under BSD/OS, NetBSD, and FreeBSD (let us know if it + * does not). + * + * Stock System Vs (and anything else using a strict-POSIX + * sigaction(2) without SA_RESTART) may have a problem. Possible + * solutions: + * + * sigvec restarts by default (SV_INTERRUPT flag to not restart) + * signal restarts by default in SVr4 (assuming you link with -lucb) + * and BSD, but not SVr3. + * sigset restarts, but is only available under SVr4/Solaris. + * + * The signal(3) call is mandated by the ANSI standard, and its + * interaction with sigaction(2) is described in the POSIX standard + * (3.3.4.2, page 72,line 934). According to section 8.1, page 191, + * however, signal(3) itself is not required by POSIX.1. And POSIX is + * silent on whether it is required to restart signals. + * + * So. The present situation is, we use sigaction(2) with no + * guarantee of restart anywhere but on Linux and BSD. We could + * switch to signal(3) and collar Linux, BSD, and SVr4. Any way + * we slice it, System V UNIXes older than SVr4 will probably lose + * (this may include XENIX). + * + * This implementation will probably be changed to use signal(3) in + * the future. If nothing else, it's simpler... + */ + +#if USE_SIGTSTP +static void +tstp(int dummy GCC_UNUSED) +{ + sigset_t mask, omask; + sigaction_t act, oact; + +#ifdef SIGTTOU + int sigttou_blocked; +#endif + + T(("tstp() called")); + + /* + * The user may have changed the prog_mode tty bits, so save them. + * + * But first try to detect whether we still are in the foreground + * process group - if not, an interactive shell may already have + * taken ownership of the tty and modified the settings when our + * parent was stopped before us, and we would likely pick up the + * settings already modified by the shell. + */ + if (SP != 0 && !SP->_endwin) /* don't do this if we're not in curses */ +#if HAVE_TCGETPGRP + if (tcgetpgrp(STDIN_FILENO) == getpgrp()) +#endif + def_prog_mode(); + + /* + * Block window change and timer signals. The latter + * is because applications use timers to decide when + * to repaint the screen. + */ + (void) sigemptyset(&mask); + (void) sigaddset(&mask, SIGALRM); +#if USE_SIGWINCH + (void) sigaddset(&mask, SIGWINCH); +#endif + (void) sigprocmask(SIG_BLOCK, &mask, &omask); + +#ifdef SIGTTOU + sigttou_blocked = sigismember(&omask, SIGTTOU); + if (!sigttou_blocked) { + (void) sigemptyset(&mask); + (void) sigaddset(&mask, SIGTTOU); + (void) sigprocmask(SIG_BLOCK, &mask, NULL); + } +#endif + + /* + * End window mode, which also resets the terminal state to the + * original (pre-curses) modes. + */ + endwin(); + + /* Unblock SIGTSTP. */ + (void) sigemptyset(&mask); + (void) sigaddset(&mask, SIGTSTP); +#ifdef SIGTTOU + if (!sigttou_blocked) { + /* Unblock this too if it wasn't blocked on entry */ + (void) sigaddset(&mask, SIGTTOU); + } +#endif + (void) sigprocmask(SIG_UNBLOCK, &mask, NULL); + + /* Now we want to resend SIGSTP to this process and suspend it */ + act.sa_handler = SIG_DFL; + sigemptyset(&act.sa_mask); + act.sa_flags = 0; +#ifdef SA_RESTART + act.sa_flags |= SA_RESTART; +#endif /* SA_RESTART */ + sigaction(SIGTSTP, &act, &oact); + kill(getpid(), SIGTSTP); + + /* Process gets suspended...time passes...process resumes */ + + T(("SIGCONT received")); + sigaction(SIGTSTP, &oact, NULL); + flushinp(); + + /* + * If the user modified the tty state while suspended, he wants + * those changes to stick. So save the new "default" terminal state. + */ + def_shell_mode(); + + /* + * This relies on the fact that doupdate() will restore the + * program-mode tty state, and issue enter_ca_mode if need be. + */ + doupdate(); + + /* Reset the signals. */ + (void) sigprocmask(SIG_SETMASK, &omask, NULL); +} +#endif /* USE_SIGTSTP */ + +static void +cleanup(int sig) +{ + /* + * Actually, doing any sort of I/O from within an signal handler is + * "unsafe". But we'll _try_ to clean up the screen and terminal + * settings on the way out. + */ + if (!_nc_globals.cleanup_nested++ + && (sig == SIGINT + || sig == SIGQUIT)) { +#if HAVE_SIGACTION || HAVE_SIGVEC + sigaction_t act; + sigemptyset(&act.sa_mask); + act.sa_flags = 0; + act.sa_handler = SIG_IGN; + if (sigaction(sig, &act, NULL) == 0) +#else + if (signal(sig, SIG_IGN) != SIG_ERR) +#endif + { + SCREEN *scan; + for (each_screen(scan)) { + if (scan->_ofp != 0 + && isatty(fileno(scan->_ofp))) { + scan->_cleanup = TRUE; + scan->_outch = _nc_outch; + } + set_term(scan); + endwin(); + if (SP) + SP->_endwin = FALSE; /* in case we have an atexit! */ + } + } + } + exit(EXIT_FAILURE); +} + +#if USE_SIGWINCH +static void +sigwinch(int sig GCC_UNUSED) +{ + _nc_globals.have_sigwinch = 1; +} +#endif /* USE_SIGWINCH */ + +/* + * If the given signal is still in its default state, set it to the given + * handler. + */ +static int +CatchIfDefault(int sig, RETSIGTYPE (*handler) (int)) +{ + int result; +#if HAVE_SIGACTION || HAVE_SIGVEC + sigaction_t old_act; + sigaction_t new_act; + + memset(&new_act, 0, sizeof(new_act)); + sigemptyset(&new_act.sa_mask); +#ifdef SA_RESTART +#ifdef SIGWINCH + if (sig != SIGWINCH) +#endif + new_act.sa_flags |= SA_RESTART; +#endif /* SA_RESTART */ + new_act.sa_handler = handler; + + if (sigaction(sig, NULL, &old_act) == 0 + && (old_act.sa_handler == SIG_DFL + || old_act.sa_handler == handler +#if USE_SIGWINCH + || (sig == SIGWINCH && old_act.sa_handler == SIG_IGN) +#endif + )) { + (void) sigaction(sig, &new_act, NULL); + result = TRUE; + } else { + result = FALSE; + } +#else /* !HAVE_SIGACTION */ + RETSIGTYPE (*ohandler) (int); + + ohandler = signal(sig, SIG_IGN); + if (ohandler == SIG_DFL + || ohandler == handler +#if USE_SIGWINCH + || (sig == SIGWINCH && ohandler == SIG_IGN) +#endif + ) { + signal(sig, handler); + result = TRUE; + } else { + signal(sig, ohandler); + result = FALSE; + } +#endif + T(("CatchIfDefault - will %scatch %s", + result ? "" : "not ", signal_name(sig))); + return result; +} + +/* + * This is invoked once at the beginning (e.g., from 'initscr()'), to + * initialize the signal catchers, and thereafter when spawning a shell (and + * returning) to disable/enable the SIGTSTP (i.e., ^Z) catcher. + * + * If the application has already set one of the signals, we'll not modify it + * (during initialization). + * + * The XSI document implies that we shouldn't keep the SIGTSTP handler if + * the caller later changes its mind, but that doesn't seem correct. + */ +NCURSES_EXPORT(void) +_nc_signal_handler(bool enable) +{ + T((T_CALLED("_nc_signal_handler(%d)"), enable)); +#if USE_SIGTSTP /* Xenix 2.x doesn't have SIGTSTP, for example */ + { + static bool ignore_tstp = FALSE; + + if (!ignore_tstp) { + static sigaction_t new_sigaction, old_sigaction; + + if (!enable) { + new_sigaction.sa_handler = SIG_IGN; + sigaction(SIGTSTP, &new_sigaction, &old_sigaction); + } else if (new_sigaction.sa_handler != SIG_DFL) { + sigaction(SIGTSTP, &old_sigaction, NULL); + } else if (sigaction(SIGTSTP, NULL, &old_sigaction) == 0 + && (old_sigaction.sa_handler == SIG_DFL)) { + sigemptyset(&new_sigaction.sa_mask); +#ifdef SA_RESTART + new_sigaction.sa_flags |= SA_RESTART; +#endif /* SA_RESTART */ + new_sigaction.sa_handler = tstp; + (void) sigaction(SIGTSTP, &new_sigaction, NULL); + } else { + ignore_tstp = TRUE; + } + } + } +#endif /* !USE_SIGTSTP */ + + if (!_nc_globals.init_signals) { + if (enable) { + CatchIfDefault(SIGINT, cleanup); + CatchIfDefault(SIGTERM, cleanup); +#if USE_SIGWINCH + CatchIfDefault(SIGWINCH, sigwinch); +#endif + _nc_globals.init_signals = TRUE; + } + } + returnVoid; +} |