1 files changed, 84 insertions, 0 deletions
diff --git a/src/util/get_hostname.c b/src/util/get_hostname.c
new file mode 100644
index 0000000..eb2cfea
--- /dev/null
+++ b/src/util/get_hostname.c
@@ -0,0 +1,84 @@
+/*++
+/* NAME
+/*	get_hostname 3
+/* SUMMARY
+/*	network name lookup
+/* SYNOPSIS
+/*	#include <get_hostname.h>
+/*
+/*	const char *get_hostname()
+/* DESCRIPTION
+/*	get_hostname() returns the local hostname as obtained
+/*	via gethostname() or its moral equivalent. This routine
+/*	goes to great length to avoid dependencies on any network
+/*	services.
+/* DIAGNOSTICS
+/*	Fatal errors: no hostname, invalid hostname.
+/* SEE ALSO
+/*	valid_hostname(3)
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/*	Wietse Venema
+/*	IBM T.J. Watson Research
+/*	P.O. Box 704
+/*	Yorktown Heights, NY 10598, USA
+/*--*/
+
+/* System library. */
+
+#include <sys_defs.h>
+#include <sys/param.h>
+#include <string.h>
+#include <unistd.h>
+
+#if (MAXHOSTNAMELEN < 256)
+#undef MAXHOSTNAMELEN
+#define MAXHOSTNAMELEN	256
+#endif
+
+/* Utility library. */
+
+#include "mymalloc.h"
+#include "msg.h"
+#include "valid_hostname.h"
+#include "get_hostname.h"
+
+/* Local stuff. */
+
+static char *my_host_name;
+
+/* get_hostname - look up my host name */
+
+const char *get_hostname(void)
+{
+    char    namebuf[MAXHOSTNAMELEN + 1];
+
+    /*
+     * The gethostname() call is not (or not yet) in ANSI or POSIX, but it is
+     * part of the socket interface library. We avoid the more politically-
+     * correct uname() routine because that has no portable way of dealing
+     * with long (FQDN) hostnames.
+     * 
+     * DO NOT CALL GETHOSTBYNAME FROM THIS FUNCTION. IT BREAKS MAILDIR DELIVERY
+     * AND OTHER THINGS WHEN THE MACHINE NAME IS NOT FOUND IN /ETC/HOSTS OR
+     * CAUSES PROCESSES TO HANG WHEN THE NETWORK IS DISCONNECTED.
+     * 
+     * POSTFIX NO LONGER NEEDS A FULLY QUALIFIED HOSTNAME. INSTEAD POSTFIX WILL
+     * USE A DEFAULT DOMAIN NAME "LOCALDOMAIN".
+     */
+    if (my_host_name == 0) {
+	/* DO NOT CALL GETHOSTBYNAME FROM THIS FUNCTION */
+	if (gethostname(namebuf, sizeof(namebuf)) < 0)
+	    msg_fatal("gethostname: %m");
+	namebuf[MAXHOSTNAMELEN] = 0;
+	/* DO NOT CALL GETHOSTBYNAME FROM THIS FUNCTION */
+	if (valid_hostname(namebuf, DO_GRIPE) == 0)
+	    msg_fatal("unable to use my own hostname");
+	/* DO NOT CALL GETHOSTBYNAME FROM THIS FUNCTION */
+	my_host_name = mystrdup(namebuf);
+    }
+    return (my_host_name);
+}