fdopendir: Fix fd leak and test failure on native Windows.

* lib/dirent-private.h: On mingw, define 'struct gl_directory' as a
wrapper around the original DIR. On MSVC, add an 'fd_to_close' field to
'struct gl_directory'.
* lib/dirent.in.h (DIR): Define when DIR_HAS_FD_MEMBER is 0, i.e. on
both mingw and MSVC.
(GNULIB_defined_DIR): New macro.
(opendir): Avoid incompatible redeclaration.
(readdir): Consider REPLACE_READDIR.
(rewinddir): Consider REPLACE_REWINDDIR.
* m4/dirent_h.m4 (gl_DIRENT_DIR): New macro.
(gl_DIRENT_H): Invoke it.
(gl_DIRENT_H_DEFAULTS): Initialize REPLACE_READDIR, REPLACE_REWINDDIR.
* modules/dirent (Makefile.am): Substitute DIR_HAS_FD_MEMBER,
REPLACE_READDIR, REPLACE_REWINDDIR.
--
* lib/dirfd.c (dirfd): If GNULIB_defined_DIR, just use the
'fd_to_close' field.
* m4/dirfd.m4 (gl_FUNC_DIRFD): Set HAVE_DIRFD. Don't set REPLACE_DIRFD
to 1 if HAVE_DIRFD is 0. If DIR_HAS_FD_MEMBER is 0, ensure dirfd.c gets
compiled.
* modules/dirfd (Files): Add lib/dirent-private.h.
(Depends-on, configure.ac): Simplify conditions.
--
* lib/closedir.c: Include <stdlib.h> always, for free().
(closedir): If GNULIB_defined_DIR, arrange to call close(dirfd(dirp)) at
the end. On mingw, call free() of dirp. Prefer testing HAVE_DIRENT_H,
for consistency with dirent.h.
* m4/closedir.m4 (gl_FUNC_CLOSEDIR): Don't set REPLACE_CLOSEDIR to 1 if
HAVE_CLOSEDIR is 0. If DIR_HAS_FD_MEMBER is 0, ensure closedir.c gets
compiled.
--
* lib/opendir.c: Include <stdlib.h> always. Include <string.h>.
(opendir): On mingw, allocate the 'struct gl_directory' through malloc.
If GNULIB_defined_DIR, set the 'fd_to_close' field to -1. Prefer
testing HAVE_DIRENT_H, for consistency with dirent.h.
* m4/opendir.m4 (gl_FUNC_OPENDIR): Don't set REPLACE_OPENDIR to 1 if
HAVE_OPENDIR is 0. If DIR_HAS_FD_MEMBER is 0, ensure opendir.c gets
compiled.
--
* lib/fdopendir.c (fdopendir): If GNULIB_defined_DIR, use a simple
implementation based on opendir and the fchdir module. If __KLIBC__,
don't define unused auxiliary functions.
* modules/fdopendir (Files): Add lib/dirent-private.h.
--
* lib/readdir.c (readdir): On mingw, redirect to the original readdir
function. Prefer testing HAVE_DIRENT_H, for consistency with dirent.h.
* m4/readdir.m4 (gl_FUNC_READDIR): If DIR_HAS_FD_MEMBER is 0, ensure
readdir.c gets compiled.
* modules/readdir (configure.ac): Consider REPLACE_READDIR.
--
* lib/rewinddir.c (rewinddir): On mingw, redirect to the original
rewinddir function. Prefer testing HAVE_DIRENT_H, for consistency with
dirent.h.
* m4/rewinddir.m4 (gl_FUNC_REWINDDIR): If DIR_HAS_FD_MEMBER is 0, ensure
rewinddir.c gets compiled.
* modules/rewinddir (configure.ac): Consider REPLACE_REWINDDIR.
--
* lib/fchdir.c (dir_info_t): Remove a FIXME.

6 files changed, 90 insertions, 44 deletions

diff --git a/m4/closedir.m4 b/m4/closedir.m4
index 9c15354c3d..7e702def25 100644
--- a/m4/closedir.m4
+++ b/m4/closedir.m4
@@ -1,4 +1,4 @@
-# closedir.m4 serial 6
+# closedir.m4 serial 7
 dnl Copyright (C) 2011-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -12,20 +12,23 @@ AC_DEFUN([gl_FUNC_CLOSEDIR],
   AC_CHECK_FUNCS([closedir])
   if test $ac_cv_func_closedir = no; then
     HAVE_CLOSEDIR=0
-  fi
-  dnl Replace closedir() for supporting the gnulib-defined fchdir() function,
-  dnl to keep fchdir's bookkeeping up-to-date.
-  m4_ifdef([gl_FUNC_FCHDIR], [
-    gl_TEST_FCHDIR
-    if test $HAVE_FCHDIR = 0; then
-      if test $HAVE_CLOSEDIR = 1; then
+  else
+    dnl Replace closedir() on native Windows, to support fdopendir().
+    AC_REQUIRE([gl_DIRENT_DIR])
+    if test $DIR_HAS_FD_MEMBER = 0; then
+      REPLACE_CLOSEDIR=1
+    fi
+    dnl Replace closedir() for supporting the gnulib-defined dirfd() function.
+    case $host_os in
+      os2*) REPLACE_CLOSEDIR=1 ;;
+    esac
+    dnl Replace closedir() for supporting the gnulib-defined fchdir() function,
+    dnl to keep fchdir's bookkeeping up-to-date.
+    m4_ifdef([gl_FUNC_FCHDIR], [
+      gl_TEST_FCHDIR
+      if test $HAVE_FCHDIR = 0; then
         REPLACE_CLOSEDIR=1
       fi
-    fi
-  ])
-  dnl Replace closedir() for supporting the gnulib-defined dirfd() function.
-  case $host_os,$HAVE_CLOSEDIR in
-    os2*,1)
-      REPLACE_CLOSEDIR=1;;
-  esac
+    ])
+  fi
 ])
diff --git a/m4/dirent_h.m4 b/m4/dirent_h.m4
index 2a232a7622..b6c189c0d9 100644
--- a/m4/dirent_h.m4
+++ b/m4/dirent_h.m4
@@ -1,4 +1,4 @@
-# dirent_h.m4 serial 19
+# dirent_h.m4 serial 20
 dnl Copyright (C) 2008-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -21,12 +21,29 @@ AC_DEFUN_ONCE([gl_DIRENT_H],
   fi
   AC_SUBST([HAVE_DIRENT_H])
 
+  gl_DIRENT_DIR
+
   dnl Check for declarations of anything we want to poison if the
   dnl corresponding gnulib module is not in use.
   gl_WARN_ON_USE_PREPARE([[#include <dirent.h>
     ]], [alphasort closedir dirfd fdopendir opendir readdir rewinddir scandir])
 ])
 
+dnl Determine whether <dirent.h> needs to override the DIR type.
+AC_DEFUN_ONCE([gl_DIRENT_DIR],
+[
+  dnl Set DIR_HAS_FD_MEMBER if dirfd() works, i.e. not always returns -1,
+  dnl or has the __KLIBC__ workaround as in lib/dirfd.c.
+  dnl We could use the findings from gl_FUNC_DIRFD and gl_PREREQ_DIRFD, but
+  dnl it's simpler since we know the affected platforms.
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  case "$host_os" in
+    mingw*) DIR_HAS_FD_MEMBER=0 ;;
+    *)      DIR_HAS_FD_MEMBER=1 ;;
+  esac
+  AC_SUBST([DIR_HAS_FD_MEMBER])
+])
+
 # gl_DIRENT_MODULE_INDICATOR([modulename])
 # sets the shell variable that indicates the presence of the given module
 # to a C preprocessor expression that will evaluate to 1.
@@ -73,6 +90,8 @@ AC_DEFUN([gl_DIRENT_H_DEFAULTS],
   HAVE_SCANDIR=1;       AC_SUBST([HAVE_SCANDIR])
   HAVE_ALPHASORT=1;     AC_SUBST([HAVE_ALPHASORT])
   REPLACE_OPENDIR=0;    AC_SUBST([REPLACE_OPENDIR])
+  REPLACE_READDIR=0;    AC_SUBST([REPLACE_READDIR])
+  REPLACE_REWINDDIR=0;  AC_SUBST([REPLACE_REWINDDIR])
   REPLACE_CLOSEDIR=0;   AC_SUBST([REPLACE_CLOSEDIR])
   REPLACE_DIRFD=0;      AC_SUBST([REPLACE_DIRFD])
   REPLACE_FDOPENDIR=0;  AC_SUBST([REPLACE_FDOPENDIR])
diff --git a/m4/dirfd.m4 b/m4/dirfd.m4
index 2135535042..d1ee2c7f61 100644
--- a/m4/dirfd.m4
+++ b/m4/dirfd.m4
@@ -1,4 +1,4 @@
-# serial 26   -*- Autoconf -*-
+# serial 27   -*- Autoconf -*-
 
 dnl Find out how to get the file descriptor associated with an open DIR*.
 
@@ -12,7 +12,7 @@ dnl From Jim Meyering
 AC_DEFUN([gl_FUNC_DIRFD],
 [
   AC_REQUIRE([gl_DIRENT_H_DEFAULTS])
-  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_REQUIRE([AC_CANONICAL_HOST])
 
   dnl Persuade glibc <dirent.h> to declare dirfd().
   AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
@@ -36,15 +36,24 @@ AC_DEFUN([gl_FUNC_DIRFD],
        [gl_cv_func_dirfd_macro=yes],
        [gl_cv_func_dirfd_macro=no])])
 
-  # Use the replacement if we have no function or macro with that name,
-  # or if OS/2 kLIBC whose dirfd() does not work.
-  # Replace only if the system declares dirfd already.
-  case $ac_cv_func_dirfd,$gl_cv_func_dirfd_macro,$host_os,$ac_cv_have_decl_dirfd in
-    no,no,*,yes | *,*,os2*,yes)
+  if test $ac_cv_func_dirfd = no && test $gl_cv_func_dirfd_macro = no; then
+    HAVE_DIRFD=0
+  else
+    HAVE_DIRFD=1
+    dnl Replace only if the system declares dirfd already.
+    if test $ac_cv_have_decl_dirfd = yes; then
       REPLACE_DIRFD=1
-      AC_DEFINE([REPLACE_DIRFD], [1],
-        [Define to 1 if gnulib's dirfd() replacement is used.]);;
-  esac
+    fi
+    dnl Replace dirfd() on native Windows, to support fdopendir().
+    AC_REQUIRE([gl_DIRENT_DIR])
+    if test $DIR_HAS_FD_MEMBER = 0; then
+      REPLACE_DIRFD=1
+    fi
+    dnl OS/2 kLIBC dirfd() does not work.
+    case "$host_os" in
+      os2*) REPLACE_DIRFD=1 ;;
+    esac
+  fi
 ])
 
 dnl Prerequisites of lib/dirfd.c.
diff --git a/m4/opendir.m4 b/m4/opendir.m4
index 2fb90b6d57..2e9be769b5 100644
--- a/m4/opendir.m4
+++ b/m4/opendir.m4
@@ -1,4 +1,4 @@
-# opendir.m4 serial 5
+# opendir.m4 serial 6
 dnl Copyright (C) 2011-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -12,21 +12,24 @@ AC_DEFUN([gl_FUNC_OPENDIR],
   AC_CHECK_FUNCS([opendir])
   if test $ac_cv_func_opendir = no; then
     HAVE_OPENDIR=0
-  fi
-  dnl Replace opendir() for supporting the gnulib-defined fchdir() function,
-  dnl to keep fchdir's bookkeeping up-to-date.
-  m4_ifdef([gl_FUNC_FCHDIR], [
-    gl_TEST_FCHDIR
-    if test $HAVE_FCHDIR = 0; then
-      if test $HAVE_OPENDIR = 1; then
+  else
+    dnl Replace opendir() on native Windows, to support fdopendir().
+    AC_REQUIRE([gl_DIRENT_DIR])
+    if test $DIR_HAS_FD_MEMBER = 0; then
+      REPLACE_OPENDIR=1
+    fi
+    dnl Replace opendir() on OS/2 kLIBC to support dirfd() function replaced
+    dnl by gnulib.
+    case $host_os in
+      os2*) REPLACE_OPENDIR=1 ;;
+    esac
+    dnl Replace opendir() for supporting the gnulib-defined fchdir() function,
+    dnl to keep fchdir's bookkeeping up-to-date.
+    m4_ifdef([gl_FUNC_FCHDIR], [
+      gl_TEST_FCHDIR
+      if test $HAVE_FCHDIR = 0; then
         REPLACE_OPENDIR=1
       fi
-    fi
-  ])
-  dnl Replace opendir() on OS/2 kLIBC to support dirfd() function replaced
-  dnl by gnulib.
-  case $host_os,$HAVE_OPENDIR in
-    os2*,1)
-      REPLACE_OPENDIR=1;;
-  esac
+    ])
+  fi
 ])
diff --git a/m4/readdir.m4 b/m4/readdir.m4
index 0a78739b3c..81337e2ffa 100644
--- a/m4/readdir.m4
+++ b/m4/readdir.m4
@@ -1,4 +1,4 @@
-# readdir.m4 serial 1
+# readdir.m4 serial 2
 dnl Copyright (C) 2011-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -11,5 +11,11 @@ AC_DEFUN([gl_FUNC_READDIR],
   AC_CHECK_FUNCS([readdir])
   if test $ac_cv_func_readdir = no; then
     HAVE_READDIR=0
+  else
+    dnl Replace readdir() on native Windows, to support fdopendir().
+    AC_REQUIRE([gl_DIRENT_DIR])
+    if test $DIR_HAS_FD_MEMBER = 0; then
+      REPLACE_READDIR=1
+    fi
   fi
 ])
diff --git a/m4/rewinddir.m4 b/m4/rewinddir.m4
index dc2c37d97a..d0d24de8a6 100644
--- a/m4/rewinddir.m4
+++ b/m4/rewinddir.m4
@@ -1,4 +1,4 @@
-# rewinddir.m4 serial 1
+# rewinddir.m4 serial 2
 dnl Copyright (C) 2011-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -11,5 +11,11 @@ AC_DEFUN([gl_FUNC_REWINDDIR],
   AC_CHECK_FUNCS([rewinddir])
   if test $ac_cv_func_rewinddir = no; then
     HAVE_REWINDDIR=0
+  else
+    dnl Replace rewinddir() on native Windows, to support fdopendir().
+    AC_REQUIRE([gl_DIRENT_DIR])
+    if test $DIR_HAS_FD_MEMBER = 0; then
+      REPLACE_REWINDDIR=1
+    fi
   fi
 ])