Don't install duplicate STREAMS modules on Solaris

Check if STREAMS modules are already installed on pty before installing
since when compiling with XPG>=4 they will likely be installed already.
Prevents hangs and duplicate lines on the terminal.  bz#2945 and bz#2998,
patch from djm@

1 files changed, 9 insertions, 0 deletions

diff --git a/openbsd-compat/bsd-openpty.c b/openbsd-compat/bsd-openpty.c
index e8ad542f8..123a9be56 100644
--- a/openbsd-compat/bsd-openpty.c
+++ b/openbsd-compat/bsd-openpty.c
@@ -121,6 +121,15 @@ openpty(int *amaster, int *aslave, char *name, struct termios *termp,
                 return (-1);
         }
 
+# if defined(I_FIND) && defined(__SVR4)
+        /*
+         * If the streams modules have already been pushed then there
+         * is no more work to do here.
+         */
+        if (ioctl(*aslave, I_FIND, "ptem") != 0)
+                return 0;
+# endif
+
         /*
          * Try to push the appropriate streams modules, as described
          * in Solaris pts(7).