(xgethostname): Protect against the SunOS5.5 bug

by allocating a larger buffer. Test the gethostname return value for
being >= 0, not == 0, for BeOS.  Don't exhaust memory if gethostname
returns an error and ENAMETOOLONG isn't defined.

1 files changed, 12 insertions, 10 deletions

diff --git a/lib/xgethostname.c b/lib/xgethostname.c
index 1139a1b19..e24124c57 100644
--- a/lib/xgethostname.c
+++ b/lib/xgethostname.c
@@ -1,5 +1,5 @@
 /* xgethostname.c -- return current hostname with unlimited length
-   Copyright (C) 1992, 1996 Free Software Foundation, Inc.
+   Copyright (C) 1992, 1996, 2000 Free Software Foundation, Inc.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -50,25 +50,27 @@ xgethostname ()
   int err;
 
   size = INITIAL_HOSTNAME_LENGTH;
-  hostname = xmalloc (size);
+  /* Use size + 1 here rather than size to work around the bug
+     in SunOS5.5's gethostname whereby it NUL-terminates HOSTNAME
+     even when the name is longer than the supplied buffer.  */
+  hostname = xmalloc (size + 1);
   while (1)
     {
-      /* Use size - 2 here rather than size - 1 to work around the bug
-	 in SunOS5.5's gethostname whereby it NUL-terminates HOSTNAME
-	 even when the name is longer than the supplied buffer.  */
-      int k = size - 2;
+      int k = size - 1;
 
       errno = 0;
       hostname[k] = '\0';
       err = gethostname (hostname, size);
-      if (err == 0 && hostname[k] == '\0')
+      if (err >= 0 && hostname[k] == '\0')
 	break;
 #ifdef ENAMETOOLONG
-      else if (err != 0 && errno != ENAMETOOLONG && errno != 0)
-	error (EXIT_FAILURE, errno, "gethostname");
+      else if (err < 0 && errno != ENAMETOOLONG && errno != 0)
+#else
+      else if (err < 0 && errno != 0)
 #endif
+	error (EXIT_FAILURE, errno, "gethostname");
       size *= 2;
-      hostname = xrealloc (hostname, size);
+      hostname = xrealloc (hostname, size + 1);
     }
 
   return hostname;