Use replacement library functions to daemonize, rather than #ifdef hell

4 files changed, 70 insertions, 33 deletions

diff --git a/configure.in b/configure.in
index fa95f4f..4d85216 100644
--- a/configure.in
+++ b/configure.in
@@ -142,7 +142,6 @@ AC_SEARCH_LIBS(gethostbyname, [nsl resolv], , [AC_MSG_ERROR(gethostbyname not fo
 AC_SEARCH_LIBS(inet_aton, [nsl resolv], , [AC_MSG_ERROR(inet_aton not found)])
 AC_SEARCH_LIBS(herror, [nsl resolv], , [AC_MSG_ERROR(herror not found)])
 
-AC_CHECK_FUNCS(dup2)
 AC_CHECK_FUNCS(fcntl)
 AC_CHECK_FUNCS(setsid)
 AC_CHECK_FUNCS(recvmsg)
@@ -174,9 +173,11 @@ SRCROOT=`cd $srcdir && pwd`
 OBJROOT=`pwd`
 
 XTRA=false
-AC_SEARCH_LIBS(xmalloc, iberty, , [XTRA=true ; AC_LIBOBJ(xmalloc)])
-AC_SEARCH_LIBS(xstrdup, iberty, , [XTRA=true ; AC_LIBOBJ(xstrdup)])
-AC_SEARCH_LIBS(bsd_signal, bsd, , [XTRA=true ; AC_LIBOBJ(bsdsignal)])
+AC_SEARCH_LIBS(xmalloc, iberty, , [XTRA=true; AC_LIBOBJ(xmalloc)])
+AC_SEARCH_LIBS(xstrdup, iberty, , [XTRA=true; AC_LIBOBJ(xstrdup)])
+AC_SEARCH_LIBS(bsd_signal, bsd, , [XTRA=true; AC_LIBOBJ(bsdsignal)])
+AC_CHECK_FUNCS(daemon, , [XTRA=true; AC_LIBOBJ(daemon)])
+AC_CHECK_FUNCS(dup2, , [XTRA=true; AC_LIBOBJ(dup2)])
 if $XTRA
 then
   XTRALIBS="$OBJROOT/lib/libxtra.a $XTRALIBS"
diff --git a/lib/daemon.c b/lib/daemon.c
new file mode 100644
index 0000000..c3106b5
--- /dev/null
+++ b/lib/daemon.c
@@ -0,0 +1,37 @@
+/*
+ * daemon.c - "daemonize" a process
+ */
+
+#include "config.h"
+
+int daemon(int nochdir, int noclose)
+{
+	int nullfd;
+	pid_t f;
+	
+	if (!nochdir) {
+		if (chdir("/"))
+			return -1;
+	}
+
+	if (!noclose) {
+		if ((nullfd = open("/dev/null", O_RDWR)) < 0 ||
+		    dup2(nullfd, 0) < 0 ||
+		    dup2(nullfd, 1) < 0 ||
+		    dup2(nullfd, 2) < 0)
+			return -1;
+		close(nullfd);
+	}
+
+	f = fork();
+	if (f < 0)
+		return -1;
+	else if (f > 0)
+		_exit(0);
+
+#ifdef HAVE_SETSID
+	return setsid();
+#else
+	return 0;
+#endif
+}
diff --git a/lib/dup2.c b/lib/dup2.c
new file mode 100644
index 0000000..bdf3325
--- /dev/null
+++ b/lib/dup2.c
@@ -0,0 +1,25 @@
+/*
+ * dup2.c
+ *
+ * Ersatz dup2() for really ancient systems
+ */
+
+#include "config.h"
+
+int dup2(int oldfd, int newfd)
+{
+  int rv, nfd;
+
+  close(newfd);
+
+  nfd = rv = dup(oldfd);
+
+  if (rv >= 0 && rv != newfd) {
+    rv = dup2(oldfd, newfd);
+    close(nfd);
+  }
+
+  return rv;
+}
+
+    
diff --git a/tftpd/tftpd.c b/tftpd/tftpd.c
index 7e0d1f0..ee65b10 100644
--- a/tftpd/tftpd.c
+++ b/tftpd/tftpd.c
@@ -1,5 +1,3 @@
-/* tftp-hpa: $Id$ */
-
 /* $OpenBSD: tftpd.c,v 1.13 1999/06/23 17:01:36 deraadt Exp $	*/
 
 /*
@@ -499,33 +497,9 @@ main(int argc, char **argv)
     }
 
     /* Daemonize this process */
-    {
-      pid_t f = fork();
-      int nfd;
-      if ( f > 0 )
-	exit(0);
-      if ( f < 0 ) {
-	syslog(LOG_ERR, "cannot fork: %m");
-	exit(EX_OSERR);
-      }
-      nfd = open("/dev/null", O_RDWR);
-      if ( nfd >= 3 ) {
-#ifdef HAVE_DUP2
-	dup2(nfd, 0);
-	dup2(nfd, 1);
-	dup2(nfd, 2);
-#else
-	close(0); dup(nfd);
-	close(1); dup(nfd);
-	close(2); dup(nfd);
-#endif
-	close(nfd);
-      } else if ( nfd < 0 ) {
-	close(0); close(1); close(2);
-      }
-#ifdef HAVE_SETSID
-      setsid();
-#endif
+    if (daemon(0, 0) < 0) {
+      syslog(LOG_ERR, "cannot daemonize: %m");
+      exit(EX_OSERR);
     }
   } else {
     /* 0 is our socket descriptor */