From df9d522301cbc3e73e9816485f7deb744ae6f373 Mon Sep 17 00:00:00 2001
From: "Eric S. Raymond" <esr@thyrsus.com>
Date: Fri, 13 Dec 2002 05:11:05 +0000
Subject: Ready to ship 6-2-0.

svn path=/trunk/; revision=3776
---
 daemon.c | 79 ++++++++++++++++++++++++++++------------------------------------
 1 file changed, 35 insertions(+), 44 deletions(-)

(limited to 'daemon.c')

diff --git a/daemon.c b/daemon.c
index a0b709d3..b5291d82 100644
--- a/daemon.c
+++ b/daemon.c
@@ -82,36 +82,54 @@ sigchld_handler (int sig)
     lastsig = SIGCHLD;
 }
 
+RETSIGTYPE null_signal_handler(int sig) { }
+
+SIGHANDLERTYPE set_signal_handler(int sig, SIGHANDLERTYPE handler)
 /* 
  * This function is called by other parts of the program to
- * setup the sigchld handler after a change to the signal context.
+ * setup the signal handler after a change to the signal context.
  * This is done to improve robustness of the signal handling code.
+ * It has the same prototype as signal(2).
  */
-void deal_with_sigchld(void)
 {
-  RETSIGTYPE sigchld_handler(int);
+  SIGHANDLERTYPE rethandler;
 #ifdef HAVE_SIGACTION
-  struct sigaction sa_new;
+  struct sigaction sa_new, sa_old;
 
   memset (&sa_new, 0, sizeof sa_new);
   sigemptyset (&sa_new.sa_mask);
-  /* sa_new.sa_handler = SIG_IGN;     pointless */
-
-  /* set up to catch child process termination signals */ 
-  sa_new.sa_handler = sigchld_handler;
+  sa_new.sa_handler = handler;
+  sa_new.sa_flags = 0;
 #ifdef SA_RESTART	/* SunOS 4.1 portability hack */
-  sa_new.sa_flags = SA_RESTART | SA_NOCLDSTOP;
+  /* system call should restart on all signals except SIGALRM */
+  if (sig != SIGALRM)
+      sa_new.sa_flags |= SA_RESTART;
 #endif
-  sigaction (SIGCHLD, &sa_new, NULL);
+#ifdef SA_NOCLDSTOP	/* SunOS 4.1 portability hack */
+  if (sig == SIGCHLD)
+      sa_new.sa_flags |= SA_NOCLDSTOP;
+#endif
+  sigaction(sig, &sa_new, &sa_old);
+  rethandler = sa_old.sa_handler;
 #if defined(SIGPWR)
-  sigaction (SIGPWR, &sa_new, NULL);
+  if (sig == SIGCHLD)
+     sigaction(SIGPWR, &sa_new, NULL);
 #endif
 #else /* HAVE_SIGACTION */
-  signal(SIGCHLD, sigchld_handler); 
+  rethandler = signal(sig, handler);
 #if defined(SIGPWR)
-  signal(SIGPWR, sigchld_handler); 
+  if (sig == SIGCHLD)
+      signal(SIGPWR, handler);
 #endif
+  /* system call should restart on all signals except SIGALRM */
+  siginterrupt(sig, sig == SIGALRM);
 #endif /* HAVE_SIGACTION */
+  return rethandler;
+}
+
+void deal_with_sigchld(void)
+{
+  set_signal_handler(SIGCHLD, sigchld_handler);
 }
 
 int
@@ -120,9 +138,6 @@ daemonize (const char *logfile, void (*termhook)(int))
 {
   int fd;
   pid_t childpid;
-#ifdef HAVE_SIGACTION
-  struct sigaction sa_new;
-#endif /* HAVE_SIGACTION */
 
   /* if we are started by init (process 1) via /etc/inittab we needn't 
      bother to detach from our process group context */
@@ -131,34 +146,14 @@ daemonize (const char *logfile, void (*termhook)(int))
     goto nottyDetach;
 
   /* Ignore BSD terminal stop signals */
-#ifdef HAVE_SIGACTION
-  memset (&sa_new, 0, sizeof sa_new);
-  sigemptyset (&sa_new.sa_mask);
-  sa_new.sa_handler = SIG_IGN;
-#ifdef SA_RESTART	/* SunOS 4.1 portability hack */
-  sa_new.sa_flags = SA_RESTART;
-#endif
-#endif /* HAVE_SIGACTION */
 #ifdef 	SIGTTOU
-#ifndef HAVE_SIGACTION
-  signal(SIGTTOU, SIG_IGN);
-#else
-  sigaction (SIGTTOU, &sa_new, NULL);
-#endif /* HAVE_SIGACTION */
+  set_signal_handler(SIGTTOU, SIG_IGN);
 #endif
 #ifdef	SIGTTIN
-#ifndef HAVE_SIGACTION
-  signal(SIGTTIN, SIG_IGN);
-#else
-  sigaction (SIGTTIN, &sa_new, NULL);
-#endif /* HAVE_SIGACTION */
+  set_signal_handler(SIGTTIN, SIG_IGN);
 #endif
 #ifdef	SIGTSTP
-#ifndef HAVE_SIGACTION
-  signal(SIGTSTP, SIG_IGN);
-#else
-  sigaction (SIGTSTP, &sa_new, NULL);
-#endif /* HAVE_SIGACTION */
+  set_signal_handler(SIGTSTP, SIG_IGN);
 #endif
 
   /* In case we were not started in the background, fork and let
@@ -199,11 +194,7 @@ daemonize (const char *logfile, void (*termhook)(int))
 #endif
   
   /* lose controlling tty */
-#ifndef HAVE_SIGACTION
-  signal(SIGHUP, SIG_IGN);
-#else
-  sigaction (SIGHUP, &sa_new, NULL);
-#endif /* HAVE_SIGACTION */
+  set_signal_handler(SIGHUP, SIG_IGN);
   if ((childpid = fork()) < 0) {
     report(stderr, "fork (%s)\n", strerror(errno));
     return(PS_IOERR);
-- 
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