partly revert change#4851, apparently POSIX::uname() may not be correct

per strict reading of standard (says Tom Christiansen)

p4raw-link: @4851 on //depot/perl: 6bb694c13adc449f32ff24c71221152025ccae6c

p4raw-id: //depot/perl@5012

1 files changed, 11 insertions, 9 deletions

diff --git a/lib/Sys/Hostname.pm b/lib/Sys/Hostname.pm
index 87d10520df..63415a6bfe 100644
--- a/lib/Sys/Hostname.pm
+++ b/lib/Sys/Hostname.pm
@@ -71,21 +71,15 @@ sub hostname {
   }
   else {  # Unix
 
-    # method 2 - use POSIX.pm, prefer the standard library to system calls
+    # method 2 - syscall is preferred since it avoids tainting problems
     eval {
 	local $SIG{__DIE__};
-	require POSIX;
-	$host = (POSIX::uname())[1];
-    }
-    # method 3 - otherwise syscall is preferred since it avoids tainting problems
-    || eval {
-	local $SIG{__DIE__};
 	require "syscall.ph";
 	$host = "\0" x 65; ## preload scalar
 	syscall(&SYS_gethostname, $host, 65) == 0;
     }
 
-    # method 3a - syscall using systeminfo instead of gethostname
+    # method 2a - syscall using systeminfo instead of gethostname
     #           -- needed on systems like Solaris
     || eval {
 	local $SIG{__DIE__};
@@ -95,13 +89,21 @@ sub hostname {
 	syscall(&SYS_systeminfo, &SI_HOSTNAME, $host, 65) != -1;
     }
 
-    # method 4 - trusty old hostname command
+    # method 3 - trusty old hostname command
     || eval {
 	local $SIG{__DIE__};
 	local $SIG{CHLD};
 	$host = `(hostname) 2>/dev/null`; # bsdish
     }
 
+    # method 4 - use POSIX::uname(), which strictly can't be expected to be
+    # correct
+    || eval {
+	local $SIG{__DIE__};
+	require POSIX;
+	$host = (POSIX::uname())[1];
+    }
+
     # method 5 - sysV uname command (may truncate)
     || eval {
 	local $SIG{__DIE__};