From af6c2cbe7a38e9d823a2900e97013d9c9d167edd Mon Sep 17 00:00:00 2001
From: Stephen Heumann <heumann1@illinois.edu>
Date: Mon, 1 Jun 2015 16:25:56 -0500
Subject: [PATCH] Add an implementation for GNO of posix_openpt and related
 functions for handling ptys.

---
 Makefile.common          |   2 +
 libtelnet/posix_openpt.c | 112 +++++++++++++++++++++++++++++++++++++++
 libtelnet/posix_openpt.h |   4 ++
 telnetd/defs.h           |   2 +
 4 files changed, 120 insertions(+)
 create mode 100644 libtelnet/posix_openpt.c
 create mode 100644 libtelnet/posix_openpt.h

diff --git a/Makefile.common b/Makefile.common
index 090da01..ce3fc01 100644
--- a/Makefile.common
+++ b/Makefile.common
@@ -18,6 +18,7 @@ TELNET_SRCS = $(TELNET_SRCS_A) $(TELNET_SRCS_B)
 
 TELNETD_SRCS = \
   libtelnet/getent.c \
+  libtelnet/posix_openpt.c \
   libtelnet/vasprintf.c \
   telnetd/global.c \
   telnetd/slc.c \
@@ -35,6 +36,7 @@ HEADERS = \
   libtelnet/strlcpy.h \
   libtelnet/vasprintf.h \
   libtelnet/inet_ntop.h \
+  libtelnet/posix_openpt.h \
   telnet/baud.h \
   telnet/defines.h \
   telnet/externs.h \
diff --git a/libtelnet/posix_openpt.c b/libtelnet/posix_openpt.c
new file mode 100644
index 0000000..607d90d
--- /dev/null
+++ b/libtelnet/posix_openpt.c
@@ -0,0 +1,112 @@
+/*-
+ * Copyright (c) 2015 Stephen Heumann
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifdef __GNO__
+
+#include <stdio.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <string.h>
+#include <unistd.h>
+
+/* Check if a given fd is the master side of a pty */
+static int is_pty(int fildes)
+{
+	char *name;
+	static const char pty_prefix[] = ".ptyq";
+	
+	name = ttyname(fildes);
+	if (strncmp(pty_prefix, name, strlen(pty_prefix)) == 0)
+		return 1;
+
+	return 0;
+}
+
+/* Open the master size of a pty */
+int posix_openpt(int oflag)
+{
+	char ptyname[7];
+	int i;
+	int master_fd, saved_errno;
+	
+	saved_errno = errno;
+	oflag &= O_RDWR | O_NOCTTY;
+	for(i = 0; i < 16; i++) {
+		snprintf(ptyname, sizeof(ptyname), ".ptyq%x", i);
+		master_fd = open(ptyname, oflag);
+		if (master_fd > 0)
+			break;
+	}
+	
+	if (master_fd < 1) {
+		if (errno != EMFILE)
+			errno = EAGAIN;
+		return -1;
+	}
+	
+	errno = saved_errno;
+	return master_fd;
+}
+
+/* Grant access to slave side of pty -- no-op on GNO */
+int grantpt(int fildes)
+{
+	if (!is_pty(fildes)) {
+		errno = EINVAL;
+		return -1;
+	}
+	
+	return 0;
+}
+
+/* Unlock a pty -- no-op on GNO */
+int unlockpt(int fildes)
+{
+	if (!is_pty(fildes)) {
+		errno = EINVAL;
+		return -1;
+	}
+	
+	return 0;
+}
+
+static char namebuf[7]; 
+
+char *ptsname(int fildes)
+{
+	if (!is_pty(fildes)) {
+		errno = EINVAL;
+		return NULL;
+	}
+	
+	strncpy(namebuf, ttyname(fildes), sizeof(namebuf));
+	namebuf[1] = 't';	/* Convert ".ptyqX" to ".ttyqX" */
+	namebuf[sizeof(namebuf)-1] = 0;
+	
+	return namebuf;
+}
+
+#endif
diff --git a/libtelnet/posix_openpt.h b/libtelnet/posix_openpt.h
new file mode 100644
index 0000000..39bb076
--- /dev/null
+++ b/libtelnet/posix_openpt.h
@@ -0,0 +1,4 @@
+int posix_openpt(int oflag);
+int grantpt(int fildes);
+int unlockpt(int fildes);
+char *ptsname(int fildes);
diff --git a/telnetd/defs.h b/telnetd/defs.h
index 56c9ad2..ccfe79a 100644
--- a/telnetd/defs.h
+++ b/telnetd/defs.h
@@ -96,9 +96,11 @@
 #else
 #include <strings.h>
 #endif
+
 #ifdef __GNO__
 # include "libtelnet/strlcpy.h"
 # include "libtelnet/vasprintf.h"
+# include "libtelnet/posix_openpt.h"
 #endif
 
 #ifndef	USE_TERMIO