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-rw-r--r--src/util/get_hostname.c84
1 files changed, 84 insertions, 0 deletions
diff --git a/src/util/get_hostname.c b/src/util/get_hostname.c
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+++ b/src/util/get_hostname.c
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+/*++
+/* 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);
+}