+/* SigHand.c
+ *
+ * Copyright (C) 2002 Simone Piccardi
+ *
+ * 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 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, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
/*****************************************************************************
*
* File SigHand.c: define a set of functions for signal manipulation
*
* Author: S. Piccardi Dec. 2002
*
- * $Id: SigHand.c,v 1.1 2002/12/03 11:06:05 piccardi Exp $
- *
*****************************************************************************/
-#include <errno.h> /* error simbol definitions */
-#include <stdio.h> /* standard I/O functions */
-#include <signal.h> /* signal handling declarations */
-#include <sys/types.h>
-#include <sys/wait.h>
+#include <errno.h> /* error definitions and routines */
+#include <stdio.h> /* standard I/O library */
+#include <signal.h> /* signal constants, types and functions */
+#include <sys/types.h> /* primitive system data types */
+#include <sys/wait.h> /* process termination constants and functions */
#include "Gapil.h"
#include "macros.h"
inline SigFunc * Signal(int signo, SigFunc *func)
{
struct sigaction new_handl, old_handl;
- new_handl.sa_handler=func;
+ new_handl.sa_handler = func; /* set signal handler */
+ /* clear signal mask: no signal blocked during execution of func */
+ if (sigemptyset(&new_handl.sa_mask)!=0){ /* initialize signal set */
+ return SIG_ERR;
+ }
+ new_handl.sa_flags=0; /* init to 0 all flags */
+ /* change action for signo signal */
+ if (sigaction(signo, &new_handl, &old_handl)){
+ return SIG_ERR;
+ }
+ return (old_handl.sa_handler);
+}
+
+/*
+ * Function SignalRestart
+ * Initialize a signal handler.
+ * To enable the signal handling a process we need to tell it to
+ * kernel; this is done writing all needed info to a sigaction structure
+ * named sigact, and then callind sigaction() system call passing the
+ * information stored in the sigact structure variable.
+ * This version enable BSD semantics with SA_RESTART
+ *
+ * Input: the signal to handle
+ * the signal handler function
+ * Return: the previous sigaction structure
+ */
+inline SigFunc * SignalRestart(int signo, SigFunc *func)
+{
+ struct sigaction new_handl, old_handl;
+ new_handl.sa_handler = func; /* set signal handler */
+ new_handl.sa_flags = SA_RESTART; /* restart system call */
/* clear signal mask: no signal blocked during execution of func */
- if (sigemptyset(&new_handl.sa_mask)!=0){ /* initialize signal set */
- perror("cannot initializes the signal set to empty"); /* see mess. */
- exit(1);
+ if (sigemptyset(&new_handl.sa_mask)!=0){ /* initialize signal set */
+ return SIG_ERR;
}
- new_handl.sa_flags=0; /* init to 0 all flags */
/* change action for signo signal */
- if (sigaction(signo,&new_handl,&old_handl)){
- perror("sigaction failed on signal action setting");
- exit(1);
+ if (sigaction(signo, &new_handl, &old_handl)){
+ return SIG_ERR;
}
return (old_handl.sa_handler);
}
+
+
/*
* Functions: HandSigCHLD
* Generic handler for SIGCHLD signal
*
* Simone Piccardi Dec. 2002
- * $Id: SigHand.c,v 1.1 2002/12/03 11:06:05 piccardi Exp $
*/
void HandSigCHLD(int sig)
{
do {
errno = 0;
pid = waitpid(WAIT_ANY, &status, WNOHANG);
- if (pid > 0) {
- debug("child %d terminated with status %x\n", pid, status);
- }
- } while ((pid > 0) && (errno == EINTR));
+// if (pid > 0) {
+// debug("child %d terminated with status %x\n", pid, status);
+// }
+ } while (pid > 0);
/* restore errno value*/
errno = errno_save;
/* return */