Add support for posix_openpt().

Instead of opening /dev/ptmx directly, we should use the proper
posix_openpt() function to obtain a pseudo-terminal. Some operating
systems, such as FreeBSD 8 and later, implement pseudo-terminal master
device nodes as a special file descriptor type, like sockets. They do
not support creation of pseudo-terminals through /dev/ptmx.

Signed-off-by: Ed Schouten <ed@80386.nl>
Reviewed-by: Guillem Jover <guillem@hadrons.org>
Reviewed-by: Alan Coopersmith <alan.coopersmith@oracle.com>
Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>

2 files changed, 5 insertions, 1 deletions

diff --git a/configure.ac b/configure.ac
index c3cd947..e9a5984 100644
--- a/configure.ac
+++ b/configure.ac
@@ -38,7 +38,7 @@ AC_CANONICAL_HOST
 
 
 AC_CHECK_HEADERS([pty.h stropts.h sys/param.h sys/select.h])
-AC_CHECK_FUNCS([select grantpt])
+AC_CHECK_FUNCS([select grantpt posix_openpt])
 
 AC_ARG_WITH(localealiasfile,
         AS_HELP_STRING([--with-localealiasfile=<path>],
diff --git a/sys.c b/sys.c
index 804bdbb..8463b05 100644
--- a/sys.c
+++ b/sys.c
@@ -335,7 +335,11 @@ allocatePty(int *pty_return, char **line_return)
 #if defined(HAVE_GRANTPT)
     int rc;
 
+#ifdef HAVE_POSIX_OPENPT
+    pty = posix_openpt(O_RDWR);
+#else
     pty = open("/dev/ptmx", O_RDWR);
+#endif
     if (pty < 0)
 	goto bsd;