1 files changed, 96 insertions, 0 deletions
diff --git a/sysdeps/unix/sysv/linux/gethostid.c b/sysdeps/unix/sysv/linux/gethostid.c
new file mode 100644
index 0000000000..94f4a1ece7
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/gethostid.c
@@ -0,0 +1,96 @@
+/* Copyright (C) 1995 Free Software Foundation, Inc.
+
+The GNU C Library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Library General Public License as
+published by the Free Software Foundation; either version 2 of the
+License, or (at your option) any later version.
+
+The GNU C Library is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+Library General Public License for more details.
+
+You should have received a copy of the GNU Library General Public
+License along with the GNU C Library; see the file COPYING.LIB.  If
+not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+Boston, MA 02111-1307, USA.  */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#define HOSTIDFILE "/var/adm/hostid"
+
+#ifdef SET_PROCEDURE
+int
+sethostid (id)
+     long int id;
+{
+  int fd;
+  ssize_t written;
+
+  /* Test for appropriate rights to set host ID.  */
+  if (geteuid () || getuid ())
+    {
+      errno = EPERM;
+      return -1;
+    }
+
+  /* Open file for writing.  Everybody is allowed to read this file.  */
+  fd = __open (HOSTIDFILE, O_CREAT|O_WRONLY, 0644);
+  if (fd < 0)
+    return -1;
+
+  written = __write (fd, &id, sizeof (id));
+
+  __close (fd);
+
+  return written != sizeof (id) ? -1 : 0;
+}
+
+#else
+# include <sys/param.h>
+# include <resolv/netdb.h>
+# include <netinet/in.h>
+
+long int
+gethostid ()
+{
+  char hostname[MAXHOSTNAMELEN + 1];
+  struct hostent *hp;
+  unsigned long id;
+  struct in_addr in;
+  int fd;
+
+  /* First try to get the ID from a former invocation of sethostid.  */
+  fd = __open (HOSTIDFILE, O_RDONLY);
+  if (fd >= 0)
+    {
+      ssize_t n = __read (fd, &id, sizeof (id));
+
+      __close (fd);
+
+      if (n == sizeof (id))
+	return id;
+    }
+
+  /* Getting from the file was not succesful.  An intelligent guess for
+     a unique number of a host is its IP address.  Return this.  */
+  if (gethostname (hostname, MAXHOSTNAMELEN) < 0 || hostname[0] == '\0')
+    /* This also fails.  Return and arbitrary value.  */
+    return 0;
+
+  /* To get the IP address we need to knoe the host name.  */
+  hp = gethostbyname (hostname);
+  if (hp == NULL)
+    return 0;
+
+  in.s_addr = 0;
+  memcpy (&in, hp->h_addr,
+	  sizeof (in) < hp->h_length ? sizeof (in) : hp->h_length);
+
+  /* For the return value to be not exactly the IP address we do some
+     bit fiddling.  */
+  return in.s_addr << 16 | in.s_addr >> 16;
+}
+#endif