[PATCH] Implement ttyname() for OS/2

[KO Myung-Hun]

OS/2 kLIBC has a declaration, but has not implemented.

* Makefile.am [OS/2]: define OS2ENV.
* configure.ac [OS/2]: define os2_SRCS.
* src/os2_ttyname.c: Implement ttyname() for OS/2.
---
 Makefile.am       |  6 ++++++
 configure.ac      |  9 ++++++++
 src/os2_ttyname.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 68 insertions(+)
 create mode 100644 src/os2_ttyname.c

diff --git a/Makefile.am b/Makefile.am
index 686851ff..e8570985 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -51,6 +51,8 @@ vms_SRCS =    src/vms_exit.c src/vms_export_symbol.c 
src/vms_progname.c \
 
 amiga_SRCS =   src/amiga.c src/amiga.h
 
+os2_SRCS =     src/os2_ttyname.c
+
 glob_SRCS =    lib/fnmatch.c lib/fnmatch.h lib/glob.c lib/glob.h
 
 alloca_SRCS =  lib/alloca.c
@@ -90,6 +92,10 @@ else
   make_SOURCES += src/posixos.c
 endif
 
+if OS2ENV
+  make_SOURCES += $(os2_SRCS)
+endif
+
 if USE_CUSTOMS
   make_SOURCES += src/remote-cstms.c
 else
diff --git a/configure.ac b/configure.ac
index f5781853..e0eca7e1 100644
--- a/configure.ac
+++ b/configure.ac
@@ -449,6 +449,15 @@ AS_CASE([$host],
     AC_DEFINE([HAVE_DOS_PATHS], [1], [Support DOS-style pathnames.])
   ])
 
+os2_target_env=no
+AM_CONDITIONAL([OS2ENV], [false])
+
+AS_CASE([$host],
+  [*-*-os2*],
+   [AM_CONDITIONAL([OS2ENV], [true])
+    os2_target_env=yes
+  ])
+
 AC_DEFINE_UNQUOTED([PATH_SEPARATOR_CHAR],['$PATH_SEPARATOR'],
         [Define to the character that separates directories in PATH.])
 
diff --git a/src/os2_ttyname.c b/src/os2_ttyname.c
new file mode 100644
index 00000000..36a79599
--- /dev/null
+++ b/src/os2_ttyname.c
@@ -0,0 +1,53 @@
+/* ttyname() implementation for OS/2
+
+Copyright (C) 2023 Free Software Foundation, Inc.
+This file is part of GNU Make.
+
+GNU Make is free software; you can redistribute it and/or modify it under the
+terms of the GNU General Public License as published by the Free Software
+Foundation; either version 3 of the License, or (at your option) any later
+version.
+
+GNU Make is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License along with
+this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+#include "makeint.h"
+
+#define INCL_DOS
+#include <os2.h>
+
+#include <unistd.h>
+
+/* OS/2 kLIBC has a declaration for ttyname(), but has not implemented.  */
+char *ttyname (int fd)
+{
+  ULONG type;
+  ULONG attr;
+  ULONG rc;
+
+  rc = DosQueryHType (fd, &type, &attr);
+  if (rc)
+    {
+      errno = EBADF;
+      return NULL;
+    }
+
+  if (type == HANDTYPE_DEVICE)
+    {
+      if ((attr & 3) == 3)
+        return (char *) "/dev/con";
+
+      if ((attr & 4) == 4)
+        return (char *) "/dev/nul";
+
+      if ((attr & 8) == 8)
+        return (char *) "/dev/clock$";
+    }
+
+  errno = ENOTTY;
+  return NULL;
+}
-- 
2.30.0