Tidy up signal handling.

All signal() calls have been changed to pending_signal() calls.
pending_signal() is defined in the new sig.c file.  It remembers
the handler and traps the signal with a function that will remember
the signal.

main.c now calls handle_signals() to actually call the required
handlers (if the above handler was called).

If this doesn't close PR2662 (was PR2347), I'll cry.

Joerg, I think this should go into 2.2, but I havn't done anything
about it because I'm bound to botch it with the new sig.[ch] files.

I've just "cvs add"'d sig.[ch] so far.... can you update to 2.2 and
tell me what you did ?  Thanks.

7 files changed, 158 insertions, 74 deletions

diff --git a/usr.sbin/ppp/Makefile b/usr.sbin/ppp/Makefile
index 4e22fb2..1423624 100644
--- a/usr.sbin/ppp/Makefile
+++ b/usr.sbin/ppp/Makefile
@@ -5,7 +5,7 @@ SRCS=	async.c auth.c ccp.c chap.c chat.c command.c filter.c fsm.c hdlc.c \
 	ip.c ipcp.c lcp.c lqr.c log.c main.c mbuf.c modem.c os.c \
 	pap.c pred.c route.c slcompress.c timer.c systems.c uucplock.c vars.c \
 	vjcomp.c arp.c alias.c alias_db.c alias_ftp.c alias_util.c \
-	passwdauth.c
+	passwdauth.c sig.c
 #CFLAGS+= -DHAVE_SHELL_CMD_WITH_ANY_MODE
 CFLAGS += -Wall -DUSE_PERROR -DMSEXT -DPASSWDAUTH
 LDADD += -lmd -lcrypt -lutil
diff --git a/usr.sbin/ppp/chat.c b/usr.sbin/ppp/chat.c
index 29f989c..25a33d3 100644
--- a/usr.sbin/ppp/chat.c
+++ b/usr.sbin/ppp/chat.c
@@ -34,7 +34,7 @@
 #include <sys/time.h>
 #include <fcntl.h>
 #include <errno.h>
-#include <signal.h>
+#include "sig.h"
 #include <sys/wait.h>
 #include "timeout.h"
 #include "vars.h"
@@ -402,16 +402,16 @@ char *command, *out;
   pipe(fids);
   pid = fork();
   if (pid == 0) {
-    signal(SIGINT, SIG_DFL);
-    signal(SIGQUIT, SIG_DFL);
-    signal(SIGTERM, SIG_DFL);
-    signal(SIGHUP, SIG_DFL);
+    pending_signal(SIGINT, SIG_DFL);
+    pending_signal(SIGQUIT, SIG_DFL);
+    pending_signal(SIGTERM, SIG_DFL);
+    pending_signal(SIGHUP, SIG_DFL);
     close(fids[0]);
     dup2(fids[1], 1);
     close(fids[1]);
     nb = open("/dev/tty", O_RDWR);
     dup2(nb, 0);
-LogPrintf(LOG_CHAT_BIT, "exec: %s\n", command);
+    LogPrintf(LOG_CHAT_BIT, "exec: %s\n", command);
     /* switch back to original privileges */
     if (setgid(getgid()) < 0) {
       LogPrintf(LOG_CHAT_BIT, "setgid: %s\n", strerror(errno));
diff --git a/usr.sbin/ppp/main.c b/usr.sbin/ppp/main.c
index 5743be0..08354e4 100644
--- a/usr.sbin/ppp/main.c
+++ b/usr.sbin/ppp/main.c
@@ -28,7 +28,7 @@
 #include <paths.h>
 #include <sys/time.h>
 #include <termios.h>
-#include <signal.h>
+#include "sig.h"
 #include <sys/wait.h>
 #include <errno.h>
 #include <netdb.h>
@@ -211,8 +211,8 @@ int signo;
 static void
 TerminalCont()
 {
-  (void)signal(SIGCONT, SIG_DFL);
-  (void)signal(SIGTSTP, TerminalStop);
+  pending_signal(SIGCONT, SIG_DFL);
+  pending_signal(SIGTSTP, TerminalStop);
   TtyCommandMode(getpgrp() == tcgetpgrp(0));
 }
 
@@ -220,9 +220,9 @@ static void
 TerminalStop(signo)
 int signo;
 {
-  (void)signal(SIGCONT, TerminalCont);
+  pending_signal(SIGCONT, TerminalCont);
   TtyOldMode();
-  signal(SIGTSTP, SIG_DFL);
+  pending_signal(SIGTSTP, SIG_DFL);
   kill(getpid(), signo);
 }
 
@@ -346,29 +346,29 @@ char **argv;
 
   tcgetattr(0, &oldtio);		/* Save original tty mode */
 
-  signal(SIGHUP, Hangup);
-  signal(SIGTERM, CloseSession);
-  signal(SIGINT, CloseSession);
-  signal(SIGQUIT, CloseSession);
+  pending_signal(SIGHUP, Hangup);
+  pending_signal(SIGTERM, CloseSession);
+  pending_signal(SIGINT, CloseSession);
+  pending_signal(SIGQUIT, CloseSession);
 #ifdef SIGSEGV
-  signal(SIGSEGV, Hangup);
+  pending_signal(SIGSEGV, Hangup);
 #endif
 #ifdef SIGPIPE
-  signal(SIGPIPE, Hangup);
+  pending_signal(SIGPIPE, Hangup);
 #endif
 #ifdef SIGALRM
-  signal(SIGALRM, SIG_IGN);
+  pending_signal(SIGALRM, SIG_IGN);
 #endif
   if(mode & MODE_INTER)
     {
 #ifdef SIGTSTP
-      signal(SIGTSTP, TerminalStop);
+      pending_signal(SIGTSTP, TerminalStop);
 #endif
 #ifdef SIGTTIN
-      signal(SIGTTIN, TerminalStop);
+      pending_signal(SIGTTIN, TerminalStop);
 #endif
 #ifdef SIGTTOU
-      signal(SIGTTOU, SIG_IGN);
+      pending_signal(SIGTTOU, SIG_IGN);
 #endif
     }
 
@@ -791,16 +791,7 @@ DoLoop()
     usleep(TICKUNIT);
     TimerService();
 #else
-    if( TimerServiceRequest > 0 ) {
-#ifdef DEBUG
-       logprintf( "Invoking TimerService before select()\n" );
-#endif
-       /* Maybe a bit cautious.... */
-       TimerServiceRequest = -1;
-       TimerService();
-       TimerServiceRequest = 0;
-       continue;
-    }
+    handle_signals();
 #endif
 
     /* If there are aren't many packets queued, look for some more. */
@@ -834,23 +825,10 @@ DoLoop()
         continue;
     }
 
-    if( TimerServiceRequest > 0 ) {
-       /* we want to service any SIGALRMs even if we got it before calling 
-          select. */
-       int rem_errno = errno;
-#ifdef DEBUG
-       logprintf( "Invoking TimerService\n" );
-#endif
-       /* Maybe a bit cautious.... */
-       TimerServiceRequest = -1;
-       TimerService();
-       TimerServiceRequest = 0;
-       errno = rem_errno;
-    }
-
     if ( i < 0 ) {
        if ( errno == EINTR ) {
-          continue;            /* Got a signal - should have been dealt with */
+          handle_signals();
+          continue;
        }
        perror("select");
        break;
diff --git a/usr.sbin/ppp/sig.c b/usr.sbin/ppp/sig.c
new file mode 100644
index 0000000..87a8c4e
--- /dev/null
+++ b/usr.sbin/ppp/sig.c
@@ -0,0 +1,89 @@
+/*-
+ * Copyright (c) 1997
+ *	Brian Somers <brian@awfulhak.demon.co.uk>.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ *
+ *  TODO:
+ *
+ */
+
+#include "sig.h"
+#include <sys/types.h>
+#include "mbuf.h"
+#include "log.h"
+
+#define __MAXSIG (32)		/* Sizeof u_long: Make life convenient.... */
+static u_long caused;				/* A mask of pending signals */
+static __sighandler_t *handler[ __MAXSIG ];	/* all start at SIG_DFL */
+
+
+/* Record a signal in the "caused" mask */
+
+static void signal_recorder(int sig) {
+    if (sig > 0 && sig <= __MAXSIG)
+        caused |= (1<<(sig-1));
+}
+
+
+/*
+    set up signal_recorder, and record handler as the function to ultimately
+    call in handle_signal()
+*/
+
+__sighandler_t *pending_signal(int sig,__sighandler_t *fn) {
+    __sighandler_t *Result;
+
+    if (sig <= 0 || sig > __MAXSIG) {
+	/* Oops - we must be a bit out of date (too many sigs ?) */
+        logprintf("Eeek! %s:%s: I must be out of date!\n",__FILE__,__LINE__);
+        return signal(sig,fn);
+    }
+
+    Result = handler[sig-1];
+    if (fn == SIG_DFL || fn == SIG_IGN) {
+        handler[sig-1] = (__sighandler_t *)0;
+        signal(sig,fn);
+    } else {
+        handler[sig-1] = fn;
+        signal(sig,signal_recorder);
+    }
+    caused &= ~(1<<(sig-1));
+    return Result;
+}
+
+
+/* Call the handlers for any pending signals */
+
+void handle_signals() {
+    int sig;
+
+    if (caused)
+       for (sig=0; sig<__MAXSIG; sig++, caused>>=1)
+           if (caused&1)
+               (*handler[sig])(sig+1);
+}
diff --git a/usr.sbin/ppp/sig.h b/usr.sbin/ppp/sig.h
new file mode 100644
index 0000000..d57c97e
--- /dev/null
+++ b/usr.sbin/ppp/sig.h
@@ -0,0 +1,41 @@
+/*-
+ * Copyright (c) 1997
+ *	Brian Somers <brian@awfulhak.demon.co.uk>.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ *
+ *  TODO:
+ *
+ */
+
+#include <sys/signal.h>
+
+/* Call this instead of signal() */
+extern __sighandler_t *pending_signal __P((int, __sighandler_t *));
+
+/* Call this when you want things to *actually* happen */
+extern void handle_signals __P((void));
diff --git a/usr.sbin/ppp/timeout.h b/usr.sbin/ppp/timeout.h
index afba12a..1da38ef 100644
--- a/usr.sbin/ppp/timeout.h
+++ b/usr.sbin/ppp/timeout.h
@@ -42,7 +42,6 @@ struct pppTimer {
 #define	TIMER_EXPIRED	2
 
 struct pppTimer *TimerList;
-extern int TimerServiceRequest;	/* If this is >0, call TimerService() */
 
 extern void StartTimer __P((struct pppTimer *));
 extern void StopTimer __P((struct pppTimer *));
diff --git a/usr.sbin/ppp/timer.c b/usr.sbin/ppp/timer.c
index b9f0acf..66d7141 100644
--- a/usr.sbin/ppp/timer.c
+++ b/usr.sbin/ppp/timer.c
@@ -25,6 +25,7 @@
 #include <sys/time.h>
 #include <signal.h>
 #include "timeout.h"
+#include "sig.h"
 #ifdef SIGALRM
 #include <errno.h>
 #endif
@@ -138,24 +139,6 @@ struct pppTimer *tp;
   tp->state = TIMER_STOPPED;
 }
 
-/*
-  This is used to decide at the top level if it's time for a TimerService()
-  call.  This'll work fine as long as select() is interrupted by the
-  SIGALRM.
-*/
-int TimerServiceRequest = 0;
-
-void
-SetTimerServiceRequest( int Sig )
-{
-  /* Maybe a bit cautious.... */
-  if( TimerServiceRequest >= 0 )
-    TimerServiceRequest++;
-#ifdef DEBUG
-  logprintf( "Setting TimerServiceRequest\n" );
-#endif
-}
-
 void
 TimerService()
 {
@@ -287,13 +270,7 @@ void usleep( u_int usec)
 void InitTimerService( void ) {
   struct itimerval itimer;
 
-  /*
-     Let's not do this - it's a bit dangerous (potential recursion into the
-     likes of malloc() etc.
-
-     signal(SIGALRM, (void (*)(int))TimerService);
-  */
-  signal(SIGALRM, SetTimerServiceRequest);
+  pending_signal(SIGALRM, (void (*)(int))TimerService);
   itimer.it_interval.tv_sec = itimer.it_value.tv_sec = 0;
   itimer.it_interval.tv_usec = itimer.it_value.tv_usec = TICKUNIT;
   setitimer(ITIMER_REAL, &itimer, NULL);
@@ -309,6 +286,6 @@ void TermTimerService( void ) {
    * Notes: after disabling timer here, we will get one
    *        SIGALRM will be got.
    */
-  signal(SIGALRM, SIG_IGN);
+  pending_signal(SIGALRM, SIG_IGN);
 }
 #endif