Fix some sched and tty tests

The ps sched test has been disabled. There are too many
odd build farms this fails in strange ways.

Other odd build farms have no tty and so some tests check
for no tty and skip if not found.

testsuite/config/unix.exp

@@ -146,3 +146,12 @@ proc kill_testproc { } {
     kill_process $testproc2_pid
     file delete $testproc_path
 }
+
+proc get_tty {} {
+    if { [catch { set raw_tty [ exec tty ] } msg]} {
+        warning "No TTY found"
+        return ""
+    }
+    regexp "/dev/(.+)" $raw_tty > tty
+    return $tty
+}

testsuite/pgrep.test/pgrep.exp

@@ -9,8 +9,7 @@ set not_uid [ expr { $uid + 1 } ]
 set gid [ exec id -g ]
 set not_gid [ expr { $gid + 1 } ] 
 set ps "${topdir}ps/pscommand"
-set raw_tty [ exec tty ]
-regexp "/dev/(.+)" $raw_tty > tty
+set tty [ get_tty ]
 
 set test "pgprep with no arguments"
 spawn $pgrep
@@ -80,8 +79,12 @@ spawn $pgrep -s 1 $testproc_comm
 expect_blank "$test"
 
 set test "pgrep matches on tty"
-spawn $pgrep -t $tty $testproc_comm
-expect_pass "$test" "^$testproc1_pid\\s+$testproc2_pid\\s*$"
+if { $tty == "" } {
+  untested "$test"
+} else {
+    spawn $pgrep -t $tty $testproc_comm
+    expect_pass "$test" "^$testproc1_pid\\s+$testproc2_pid\\s*$"
+}
 
 set test "pgrep doesn't match with bogus tty"
 spawn $pgrep -t glass $testproc_comm

testsuite/pkill.test/pkill.exp

@@ -9,8 +9,7 @@ set not_uid [ expr { $uid + 1 } ]
 set gid [ exec id -g ]
 set not_gid [ expr { $gid + 1 } ] 
 set ps "${topdir}ps/pscommand"
-set raw_tty [ exec tty ]
-regexp "/dev/(.+)" $raw_tty > tty
+set tty [ get_tty ]
 
 set test "pkill with no arguments"
 spawn $pkill

testsuite/ps.test/ps_output.exp

@@ -9,8 +9,6 @@ set uid [ exec id -u ]
 set not_uid [ expr { $uid + 1 } ] 
 set gid [ exec id -g ]
 set not_gid [ expr { $gid + 1 } ] 
-set raw_tty [ exec tty ]
-regexp "/dev/(.+)" $raw_tty > tty
 
 # All the fields
 # Cannot do args,cmd,comm

testsuite/ps.test/ps_sched_batch.exp

@@ -1,12 +1,14 @@
 #
 # check the ps SCHED_BATCH scheduler policy output
 #
-set ps "${topdir}ps/pscommand"
-set schedbatch "${topdir}testsuite/test-schedbatch"
-
-spawn $schedbatch 18
-
+# This is too flaky on certain build systems to be
+# reliable - CS
+#set ps "${topdir}ps/pscommand"
+#set schedbatch "${topdir}testsuite/test-schedbatch"
+#
+#spawn $schedbatch 18
+#
 set test "ps SCHED_BATCH scheduler"
-spawn $ps --no-header -o comm,cls,nice -a
-expect_pass "$test" "\\s+test-schedbatch\\s+B\\s+18"
+#spawn $ps --no-header -o comm,cls,nice -a
+#expect_pass "$test" "\\s+test-schedbatch\\s+B\\s+18"
 untested "$test"