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Diffstat (limited to 'signals.c')
| -rw-r--r-- | signals.c | 251 |
1 files changed, 251 insertions, 0 deletions
diff --git a/signals.c b/signals.c new file mode 100644 index 0000000..ec73792 --- /dev/null +++ b/signals.c @@ -0,0 +1,251 @@ +/* $Xorg: signals.c,v 1.4 2001/02/09 02:06:01 xorgcvs Exp $ */ +/****************************************************************************** + +Copyright 1994, 1998 The Open Group + +Permission to use, copy, modify, distribute, and sell this software and its +documentation for any purpose is hereby granted without fee, provided that +the above copyright notice appear in all copies and that both that +copyright notice and this permission notice appear in supporting +documentation. + +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 +OPEN GROUP 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 of The Open Group shall not be +used in advertising or otherwise to promote the sale, use or other dealings +in this Software without prior written authorization from The Open Group. +******************************************************************************/ + +#include <X11/Xos.h> +#include <X11/Xfuncs.h> + +#include <X11/SM/SMlib.h> + +#ifdef USG +#ifndef __TYPES__ +#include <sys/types.h> /* forgot to protect it... */ +#define __TYPES__ +#endif /* __TYPES__ */ +#else +#if defined(_POSIX_SOURCE) && defined(MOTOROLA) +#undef _POSIX_SOURCE +#include <sys/types.h> +#define _POSIX_SOURCE +#else +#include <sys/types.h> +#endif +#endif /* USG */ + +#ifdef X_POSIX_C_SOURCE +#define _POSIX_C_SOURCE X_POSIX_C_SOURCE +#include <signal.h> +#include <sys/wait.h> +#undef _POSIX_C_SOURCE +#else +#if defined(X_NOT_POSIX) || defined(_POSIX_SOURCE) +#include <signal.h> +#include <sys/wait.h> +#else +#define _POSIX_SOURCE +#include <signal.h> +#include <sys/wait.h> +#undef _POSIX_SOURCE +#endif +#endif + +#if defined(X_NOT_POSIX) && defined(SIGNALRETURNSINT) +#define SIGVAL int +#else +#define SIGVAL void +#endif + +#ifndef X_NOT_POSIX +#define USE_POSIX_WAIT +#endif + +#if defined(linux) || defined(SYSV) +#define USE_SYSV_SIGNALS +#endif + +#if defined(SCO) || defined(ISC) +#undef SIGTSTP /* defined, but not the BSD way */ +#endif + +#if defined(X_NOT_POSIX) && defined(SYSV) +#define SIGNALS_RESET_WHEN_CAUGHT +#endif + +#ifndef NULL +#define NULL 0 +#endif + +int checkpoint_from_signal = 0; + +extern Bool wantShutdown; + + +SIGVAL (*Signal (sig, handler))() + int sig; + SIGVAL (*handler)(); +{ +#ifndef X_NOT_POSIX + struct sigaction sigact, osigact; + sigact.sa_handler = handler; + sigemptyset(&sigact.sa_mask); + sigact.sa_flags = 0; + sigaction(sig, &sigact, &osigact); + return osigact.sa_handler; +#else + return signal(sig, handler); +#endif +} + + +void +sig_child_handler () + +{ + int pid; + +#if !defined(USE_POSIX_WAIT) && (defined(USE_SYSV_SIGNALS) && \ + (defined(CRAY) || !defined(SIGTSTP))) + wait (NULL); +#endif + +#ifdef SIGNALS_RESET_WHEN_CAUGHT + Signal (SIGCHLD, sig_child_handler); +#endif + + /* + * The wait() above must come before re-establishing the signal handler. + * In between this time, a new child might have died. If we can do + * a non-blocking wait, we can check for this race condition. If we + * don't have non-blocking wait, we lose. + */ + + do + { +#ifdef USE_POSIX_WAIT + pid = waitpid (-1, NULL, WNOHANG); +#else +#if defined(USE_SYSV_SIGNALS) && (defined(CRAY) || !defined(SIGTSTP)) + /* cannot do non-blocking wait */ + pid = 0; +#else + union wait status; + + pid = wait3 (&status, WNOHANG, (struct rusage *)NULL); +#endif +#endif /* USE_POSIX_WAIT else */ + } + while (pid > 0); +} + + +void +sig_term_handler () + +{ + wantShutdown = 1; + checkpoint_from_signal = 1; + DoSave (SmSaveLocal, SmInteractStyleNone, 1 /* fast */); +} + + +void +sig_usr1_handler () + +{ + wantShutdown = 0; + checkpoint_from_signal = 1; + DoSave (SmSaveLocal, SmInteractStyleNone, 0 /* fast */); +} + + + +void +register_signals () + +{ + /* + * Ignore SIGPIPE + */ + + Signal (SIGPIPE, SIG_IGN); + + + /* + * If child process dies, call our handler + */ + + Signal (SIGCHLD, sig_child_handler); + + + /* + * If we get a SIGTERM, do shutdown, fast, local, no interact + */ + + Signal (SIGTERM, sig_term_handler); + + + /* + * If we get a SIGUSR1, do checkpoint, local, no interact + */ + + Signal (SIGUSR1, sig_usr1_handler); +} + + + +int +execute_system_command (s) + +char *s; + +{ + int stat; + +#ifdef X_NOT_POSIX + /* + * Non-POSIX system() uses wait(). We must disable our sig child + * handler because if it catches the signal, system() will block + * forever in wait(). + */ + + int pid; + + Signal (SIGCHLD, SIG_IGN); +#endif + + stat = system (s); + +#ifdef X_NOT_POSIX + /* + * Re-enable our sig child handler. We might have missed some signals, + * so do non-blocking waits until there are no signals left. + */ + + Signal (SIGCHLD, sig_child_handler); + +#if !(defined(USE_SYSV_SIGNALS) && (defined(CRAY) || !defined(SIGTSTP))) + do + { + union wait status; + + pid = wait3 (&status, WNOHANG, (struct rusage *)NULL); + } while (pid > 0); +#endif +#endif /* X_NOT_POSIX */ + + return (stat); +} + + |