ptsname_r: new module

For now, this replacement focuses solely on compilation
compatibility, and assumes that isatty() and ttyname_r() work
on a master side pty; if this assumption fails, or if
thread-safety is also required, then a later patch can follow
the lead of strerror_r.c in wrapping the system ptsname()
with a lock.

* modules/ptsname_r: New module.
* m4/ptsname_r.m4 (gl_FUNC_PTSNAME_R): New file.
* lib/ptsname.c (__ptsname_r): Split...
* lib/ptsname_r.c: ...into new file.
* m4/stdlib_h.m4 (gl_STDLIB_H): Check for decl.
(gl_STDLIB_H_DEFAULTS): Set witness defaults.
* modules/stdlib (Makefile.am): Substitute witnesses.
* lib/stdlib.in.h (ptsname_r): Declare it.
* doc/glibc-functions/ptsname_r.texi (ptsname_r): Document it.
* MODULES.html.sh (Misc): Likewise.
* modules/ptsname (Depends-on): Alter dependency.
* doc/posix-functions/ptsname.texi (ptsname): Mention new module.

Signed-off-by: Eric Blake <eblake@redhat.com>

12 files changed, 194 insertions, 76 deletions

diff --git a/ChangeLog b/ChangeLog
index 83c2d12480..8aacfdaf4a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,19 @@
+2011-11-09  Eric Blake  <eblake@redhat.com>
+
+	ptsname_r: new module
+	* modules/ptsname_r: New module.
+	* m4/ptsname_r.m4 (gl_FUNC_PTSNAME_R): New file.
+	* lib/ptsname.c (__ptsname_r): Split...
+	* lib/ptsname_r.c: ...into new file.
+	* m4/stdlib_h.m4 (gl_STDLIB_H): Check for decl.
+	(gl_STDLIB_H_DEFAULTS): Set witness defaults.
+	* modules/stdlib (Makefile.am): Substitute witnesses.
+	* lib/stdlib.in.h (ptsname_r): Declare it.
+	* doc/glibc-functions/ptsname_r.texi (ptsname_r): Document it.
+	* MODULES.html.sh (Misc): Likewise.
+	* modules/ptsname (Depends-on): Alter dependency.
+	* doc/posix-functions/ptsname.texi (ptsname): Mention new module.
+
 2011-11-09  Jim Meyering  <meyering@redhat.com>
 
 	announce-gen: be more concise when there's only one URL+tarball
diff --git a/MODULES.html.sh b/MODULES.html.sh
index 34ca5cc3d7..bc8a1a6a68 100755
--- a/MODULES.html.sh
+++ b/MODULES.html.sh
@@ -3447,6 +3447,7 @@ func_all_modules ()
   func_module physmem
   func_module posixver
   func_module progname
+  func_module ptsname_r
   func_module pty
   func_module quotearg
   func_module quote
diff --git a/doc/glibc-functions/ptsname_r.texi b/doc/glibc-functions/ptsname_r.texi
index cbaa2d31a7..986e4910f4 100644
--- a/doc/glibc-functions/ptsname_r.texi
+++ b/doc/glibc-functions/ptsname_r.texi
@@ -2,15 +2,17 @@
 @subsection @code{ptsname_r}
 @findex ptsname_r
 
-Gnulib module: ---
+Gnulib module: ptsname_r
 
 Portability problems fixed by Gnulib:
 @itemize
+@item
+This function is missing on some platforms:
+MacOS X 10.5, FreeBSD 6.0, NetBSD 5.0, OpenBSD 3.8, Minix 3.1.8,
+AIX 5.1, HP-UX 11, IRIX 6.5, Solaris 11 2010-11, Cygwin 1.7.9, mingw,
+MSVC 9, BeOS.
 @end itemize
 
 Portability problems not fixed by Gnulib:
 @itemize
-@item
-This function is missing on some platforms:
-MacOS X 10.5, FreeBSD 6.0, NetBSD 5.0, OpenBSD 3.8, Minix 3.1.8, AIX 5.1, HP-UX 11, IRIX 6.5, Solaris 11 2010-11, Cygwin, mingw, MSVC 9, BeOS.
 @end itemize
diff --git a/doc/posix-functions/ptsname.texi b/doc/posix-functions/ptsname.texi
index e585390c43..2584af860e 100644
--- a/doc/posix-functions/ptsname.texi
+++ b/doc/posix-functions/ptsname.texi
@@ -21,4 +21,11 @@ IRIX 5.3.
 @item
 On Solaris 11 2010-11, this function fails on all BSD-style @file{/dev/pty*}
 device files.
+@item
+This function is not thread-safe on some platforms:
+Cygwin 1.7.9.
+Likewise, the gnulib replacement is not thread-safe.
 @end itemize
+
+Note that the Gnulib module @code{ptsname_r} is a version of this
+function that is more likely to be thread-safe.
diff --git a/lib/ptsname.c b/lib/ptsname.c
index cd2cc5ee97..102a65c90a 100644
--- a/lib/ptsname.c
+++ b/lib/ptsname.c
@@ -18,30 +18,6 @@
 
 #include <stdlib.h>
 
-#include <errno.h>
-#include <string.h>
-#include <sys/stat.h>
-#include <unistd.h>
-
-#ifdef _LIBC
-# include <paths.h>
-#else
-# ifndef _PATH_TTY
-#  define _PATH_TTY "/dev/tty"
-# endif
-# ifndef _PATH_DEV
-#  define _PATH_DEV "/dev/"
-# endif
-
-# define __set_errno(e) errno = (e)
-# define __isatty isatty
-# define __stat stat
-# define __ttyname_r ttyname_r
-
-static int __ptsname_r (int fd, char *buf, size_t buflen);
-#endif
-
-
 /* Static buffer for `ptsname'.  */
 static char buffer[64];
 
@@ -52,48 +28,5 @@ static char buffer[64];
 char *
 ptsname (int fd)
 {
-  return __ptsname_r (fd, buffer, sizeof (buffer)) != 0 ? NULL : buffer;
-}
-
-
-/* Store at most BUFLEN characters of the pathname of the slave pseudo
-   terminal associated with the master FD is open on in BUF.
-   Return 0 on success, otherwise an error number.  */
-static int
-__ptsname_r (int fd, char *buf, size_t buflen)
-{
-  int save_errno = errno;
-  int err;
-  struct stat st;
-
-  if (buf == NULL)
-    {
-      __set_errno (EINVAL);
-      return EINVAL;
-    }
-
-  if (!__isatty (fd))
-    /* We rely on isatty to set errno properly (i.e. EBADF or ENOTTY).  */
-    return errno;
-
-  if (buflen < strlen (_PATH_TTY) + 3)
-    {
-      __set_errno (ERANGE);
-      return ERANGE;
-    }
-
-  err = __ttyname_r (fd, buf, buflen);
-  if (err != 0)
-    {
-      __set_errno (err);
-      return errno;
-    }
-
-  buf[sizeof (_PATH_DEV) - 1] = 't';
-
-  if (__stat (buf, &st) < 0)
-    return errno;
-
-  __set_errno (save_errno);
-  return 0;
+  return ptsname_r (fd, buffer, sizeof (buffer)) != 0 ? NULL : buffer;
 }
diff --git a/lib/ptsname_r.c b/lib/ptsname_r.c
new file mode 100644
index 0000000000..e7f2d5b9ef
--- /dev/null
+++ b/lib/ptsname_r.c
@@ -0,0 +1,85 @@
+/* Determine name of the slave side of a pseudo-terminal.
+   Copyright (C) 1998, 2002, 2010-2011 Free Software Foundation, Inc.
+
+   This program 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.
+
+   This program 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 <http://www.gnu.org/licenses/>.  */
+
+#include <config.h>
+
+#include <stdlib.h>
+
+#include <errno.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#ifdef _LIBC
+# include <paths.h>
+#else
+# ifndef _PATH_TTY
+#  define _PATH_TTY "/dev/tty"
+# endif
+# ifndef _PATH_DEV
+#  define _PATH_DEV "/dev/"
+# endif
+
+# define __set_errno(e) errno = (e)
+# define __isatty isatty
+# define __stat stat
+# define __ttyname_r ttyname_r
+# define __ptsname_r ptsname_r
+
+#endif
+
+
+/* Store at most BUFLEN characters of the pathname of the slave pseudo
+   terminal associated with the master FD is open on in BUF.
+   Return 0 on success, otherwise an error number.  */
+int
+__ptsname_r (int fd, char *buf, size_t buflen)
+{
+  int save_errno = errno;
+  int err;
+  struct stat st;
+
+  if (buf == NULL)
+    {
+      __set_errno (EINVAL);
+      return EINVAL;
+    }
+
+  if (!__isatty (fd))
+    /* We rely on isatty to set errno properly (i.e. EBADF or ENOTTY).  */
+    return errno;
+
+  if (buflen < strlen (_PATH_TTY) + 3)
+    {
+      __set_errno (ERANGE);
+      return ERANGE;
+    }
+
+  err = __ttyname_r (fd, buf, buflen);
+  if (err != 0)
+    {
+      __set_errno (err);
+      return errno;
+    }
+
+  buf[sizeof (_PATH_DEV) - 1] = 't';
+
+  if (__stat (buf, &st) < 0)
+    return errno;
+
+  __set_errno (save_errno);
+  return 0;
+}
diff --git a/lib/stdlib.in.h b/lib/stdlib.in.h
index 1a8df492c9..009b180cf3 100644
--- a/lib/stdlib.in.h
+++ b/lib/stdlib.in.h
@@ -455,6 +455,23 @@ _GL_WARN_ON_USE (ptsname, "ptsname is not portable - "
 # endif
 #endif
 
+#if @GNULIB_PTSNAME_R@
+/* Set the pathname of the pseudo-terminal slave associated with
+   the master FD is open on and return 0, or set errno and return
+   non-zero on errors.  */
+# if !@HAVE_PTSNAME_R@
+_GL_FUNCDECL_SYS (ptsname_r, int, (int fd, char *buf, size_t len));
+# endif
+_GL_CXXALIAS_SYS (ptsname_r, int, (int fd, char *buf, size_t len));
+_GL_CXXALIASWARN (ptsname_r);
+#elif defined GNULIB_POSIXCHECK
+# undef ptsname_r
+# if HAVE_RAW_DECL_PTSNAME_R
+_GL_WARN_ON_USE (ptsname_r, "ptsname_r is not portable - "
+                 "use gnulib module ptsname_r for portability");
+# endif
+#endif
+
 #if @GNULIB_PUTENV@
 # if @REPLACE_PUTENV@
 #  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
diff --git a/m4/ptsname_r.m4 b/m4/ptsname_r.m4
new file mode 100644
index 0000000000..fb070998ed
--- /dev/null
+++ b/m4/ptsname_r.m4
@@ -0,0 +1,23 @@
+# ptsname_r.m4 serial 1
+dnl Copyright (C) 2010-2011 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_PTSNAME_R],
+[
+  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+
+  dnl Persuade glibc <stdlib.h> to declare ptsname_r().
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+
+  AC_CHECK_FUNCS_ONCE([ptsname_r])
+  if test $ac_cv_func_ptsname_r = no; then
+    HAVE_PTSNAME_R=0
+  fi
+])
+
+# Prerequisites of lib/ptsname.c.
+AC_DEFUN([gl_PREREQ_PTSNAME_R], [
+  :
+])
diff --git a/m4/stdlib_h.m4 b/m4/stdlib_h.m4
index fbdba980eb..ebf7fb52a9 100644
--- a/m4/stdlib_h.m4
+++ b/m4/stdlib_h.m4
@@ -1,4 +1,4 @@
-# stdlib_h.m4 serial 37
+# stdlib_h.m4 serial 38
 dnl Copyright (C) 2007-2011 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -21,8 +21,8 @@ AC_DEFUN([gl_STDLIB_H],
 #endif
     ]], [_Exit atoll canonicalize_file_name getloadavg getsubopt grantpt
     initstate_r mkdtemp mkostemp mkostemps mkstemp mkstemps posix_openpt
-    ptsname random_r realpath rpmatch setenv setstate_r srandom_r strtod
-    strtoll strtoull unlockpt unsetenv])
+    ptsname ptsname_r random_r realpath rpmatch setenv setstate_r srandom_r
+    strtod strtoll strtoull unlockpt unsetenv])
 ])
 
 AC_DEFUN([gl_STDLIB_MODULE_INDICATOR],
@@ -52,6 +52,7 @@ AC_DEFUN([gl_STDLIB_H_DEFAULTS],
   GNULIB_MKSTEMPS=0;      AC_SUBST([GNULIB_MKSTEMPS])
   GNULIB_POSIX_OPENPT=0;  AC_SUBST([GNULIB_POSIX_OPENPT])
   GNULIB_PTSNAME=0;       AC_SUBST([GNULIB_PTSNAME])
+  GNULIB_PTSNAME_R=0;     AC_SUBST([GNULIB_PTSNAME_R])
   GNULIB_PUTENV=0;        AC_SUBST([GNULIB_PUTENV])
   GNULIB_RANDOM_R=0;      AC_SUBST([GNULIB_RANDOM_R])
   GNULIB_REALLOC_POSIX=0; AC_SUBST([GNULIB_REALLOC_POSIX])
@@ -79,6 +80,7 @@ AC_DEFUN([gl_STDLIB_H_DEFAULTS],
   HAVE_MKSTEMPS=1;           AC_SUBST([HAVE_MKSTEMPS])
   HAVE_POSIX_OPENPT=1;       AC_SUBST([HAVE_POSIX_OPENPT])
   HAVE_PTSNAME=1;            AC_SUBST([HAVE_PTSNAME])
+  HAVE_PTSNAME_R=1;          AC_SUBST([HAVE_PTSNAME_R])
   HAVE_RANDOM_H=1;           AC_SUBST([HAVE_RANDOM_H])
   HAVE_RANDOM_R=1;           AC_SUBST([HAVE_RANDOM_R])
   HAVE_REALPATH=1;           AC_SUBST([HAVE_REALPATH])
diff --git a/modules/ptsname b/modules/ptsname
index 58560d63e5..f0ce25600d 100644
--- a/modules/ptsname
+++ b/modules/ptsname
@@ -8,7 +8,7 @@ m4/ptsname.m4
 Depends-on:
 stdlib
 extensions
-ttyname_r       [test $HAVE_PTSNAME = 0]
+ptsname_r       [test $HAVE_PTSNAME = 0]
 
 configure.ac:
 gl_FUNC_PTSNAME
diff --git a/modules/ptsname_r b/modules/ptsname_r
new file mode 100644
index 0000000000..daf1d98125
--- /dev/null
+++ b/modules/ptsname_r
@@ -0,0 +1,30 @@
+Description:
+ptsname_r() function: Determine name of the slave side of a pseudo-terminal.
+
+Files:
+lib/ptsname_r.c
+m4/ptsname_r.m4
+
+Depends-on:
+stdlib
+extensions
+ttyname_r       [test $HAVE_PTSNAME_R = 0]
+
+configure.ac:
+gl_FUNC_PTSNAME_R
+if test $HAVE_PTSNAME_R = 0; then
+  AC_LIBOBJ([ptsname_r])
+  gl_PREREQ_PTSNAME_R
+fi
+gl_STDLIB_MODULE_INDICATOR([ptsname_r])
+
+Makefile.am:
+
+Include:
+<stdlib.h>
+
+License:
+LGPLv2+
+
+Maintainer:
+Bruno Haible, Eric Blake
diff --git a/modules/stdlib b/modules/stdlib
index 707d5e5d7d..d46f66412a 100644
--- a/modules/stdlib
+++ b/modules/stdlib
@@ -47,6 +47,7 @@ stdlib.h: stdlib.in.h $(top_builddir)/config.status $(CXXDEFS_H) \
 	      -e 's/@''GNULIB_MKSTEMPS''@/$(GNULIB_MKSTEMPS)/g' \
 	      -e 's/@''GNULIB_POSIX_OPENPT''@/$(GNULIB_POSIX_OPENPT)/g' \
 	      -e 's/@''GNULIB_PTSNAME''@/$(GNULIB_PTSNAME)/g' \
+	      -e 's/@''GNULIB_PTSNAME_R''@/$(GNULIB_PTSNAME_R)/g' \
 	      -e 's/@''GNULIB_PUTENV''@/$(GNULIB_PUTENV)/g' \
 	      -e 's/@''GNULIB_RANDOM_R''@/$(GNULIB_RANDOM_R)/g' \
 	      -e 's/@''GNULIB_REALLOC_POSIX''@/$(GNULIB_REALLOC_POSIX)/g' \
@@ -74,6 +75,7 @@ stdlib.h: stdlib.in.h $(top_builddir)/config.status $(CXXDEFS_H) \
 	      -e 's|@''HAVE_MKSTEMPS''@|$(HAVE_MKSTEMPS)|g' \
 	      -e 's|@''HAVE_POSIX_OPENPT''@|$(HAVE_POSIX_OPENPT)|g' \
 	      -e 's|@''HAVE_PTSNAME''@|$(HAVE_PTSNAME)|g' \
+	      -e 's|@''HAVE_PTSNAME_R''@|$(HAVE_PTSNAME_R)|g' \
 	      -e 's|@''HAVE_RANDOM_H''@|$(HAVE_RANDOM_H)|g' \
 	      -e 's|@''HAVE_RANDOM_R''@|$(HAVE_RANDOM_R)|g' \
 	      -e 's|@''HAVE_REALPATH''@|$(HAVE_REALPATH)|g' \