[v4,02/13] support: Add <support/xdirent.h>

diff --git a/support/Makefile b/support/Makefile
index 6e3c55394f..ce194bfdd4 100644
--- a/support/Makefile
+++ b/support/Makefile
@@ -73,6 +73,8 @@  libsupport-routines = \
   support_quote_blob \
   support_quote_blob_wide \
   support_quote_string \
+  support_readdir_check \
+  support_readdir_r_check \
   support_record_failure \
   support_run_diff \
   support_select_modifies_timeout \
@@ -115,6 +117,7 @@  libsupport-routines = \
   xclock_settime_time64 \
   xclone \
   xclose \
+  xclosedir \
   xconnect \
   xcopy_file_range \
   xdlfcn \
@@ -122,6 +125,7 @@  libsupport-routines = \
   xdup2 \
   xfchmod \
   xfclose \
+  xfdopendir \
   xfgets \
   xfopen \
   xfork \
@@ -143,6 +147,7 @@  libsupport-routines = \
   xmunmap \
   xnewlocale \
   xopen \
+  xopendir \
   xpipe \
   xpoll \
   xposix_memalign \
@@ -327,6 +332,7 @@  tests = \
   tst-test_compare_string \
   tst-test_compare_string_wide \
   tst-timespec \
+  tst-xdirent \
   tst-xreadlink \
   tst-xsigstack \
   # tests
diff --git a/support/support_readdir_check.c b/support/support_readdir_check.c
new file mode 100644
index 0000000000..8d48a4c5a4
--- /dev/null
+++ b/support/support_readdir_check.c
@@ -0,0 +1,29 @@ 
+/* Error-checking helper for xreaddir, xreaddir64.
+   Copyright (C) 2024 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <support/xdirent.h>
+
+#include <support/check.h>
+
+void *
+support_readdir_check (const char *name, void *result)
+{
+  if (result == NULL && errno != 0)
+    FAIL_EXIT1 ("%s: %m", name);
+  return result;
+}
diff --git a/support/support_readdir_r_check.c b/support/support_readdir_r_check.c
new file mode 100644
index 0000000000..8675b08ff3
--- /dev/null
+++ b/support/support_readdir_r_check.c
@@ -0,0 +1,29 @@ 
+/* Error-checking helper for xreaddir_r, xreaddir64_r.
+   Copyright (C) 2024 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <support/xdirent.h>
+
+#include <support/check.h>
+
+int
+support_readdir_r_check (const char *name, int result)
+{
+  if (result != 0)
+    FAIL_EXIT1 ("%s: %m", name);
+  return result;
+}
diff --git a/support/tst-xdirent.c b/support/tst-xdirent.c
new file mode 100644
index 0000000000..7012b3185b
--- /dev/null
+++ b/support/tst-xdirent.c
@@ -0,0 +1,70 @@ 
+/* Compile test for error-checking wrappers for <dirent.h>
+   Copyright (C) 2024 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <support/xdirent.h>
+
+#include <libc-diag.h>
+#include <support/check.h>
+#include <unistd.h>
+
+static int
+do_test (void)
+{
+  {
+    DIR *d = xopendir (".");
+    struct dirent *e = xreaddir (d);
+    /* Assume that the "." special entry always comes first.  */
+    TEST_COMPARE_STRING (e->d_name, ".");
+    xclosedir (d);
+  }
+
+  {
+    DIR *d = xopendir (".");
+    struct dirent64 *e = xreaddir64 (d);
+    TEST_COMPARE_STRING (e->d_name, ".");
+    xclosedir (d);
+  }
+
+  /* The functions readdir_r, readdir64_r were deprecated in glibc 2.24.  */
+  DIAG_PUSH_NEEDS_COMMENT;
+  DIAG_IGNORE_NEEDS_COMMENT (4.9, "-Wdeprecated-declarations");
+
+  {
+    DIR *d = xopendir (".");
+    struct dirent buf;
+    struct dirent *e;
+    TEST_COMPARE (xreaddir_r (d, &buf, &e), 0);
+    TEST_COMPARE_STRING (e->d_name, ".");
+    xclosedir (d);
+  }
+
+  {
+    DIR *d = xopendir (".");
+    struct dirent64 buf;
+    struct dirent64 *e;
+    TEST_COMPARE (xreaddir64_r (d, &buf, &e), 0);
+    TEST_COMPARE_STRING (e->d_name, ".");
+    xclosedir (d);
+  }
+
+  DIAG_POP_NEEDS_COMMENT;
+
+  return 0;
+}
+
+#include <support/test-driver.c>
diff --git a/support/xclosedir.c b/support/xclosedir.c
new file mode 100644
index 0000000000..b490df5598
--- /dev/null
+++ b/support/xclosedir.c
@@ -0,0 +1,28 @@ 
+/* Error-checking wrapper for closedir.
+   Copyright (C) 2024 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <support/xdirent.h>
+
+#include <support/check.h>
+
+void
+xclosedir (DIR *dir)
+{
+  if (closedir (dir) != 0)
+    FAIL_EXIT1 ("closedir: %m");
+}
diff --git a/support/xdirent.h b/support/xdirent.h
new file mode 100644
index 0000000000..83f41dba6b
--- /dev/null
+++ b/support/xdirent.h
@@ -0,0 +1,53 @@ 
+/* Error-checking wrappers for <dirent.h>
+   Copyright (C) 2024 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef SUPPORT_XDIRENT_H
+#define SUPPORT_XDIRENT_H
+
+#include <dirent.h>
+#include <errno.h>
+#include <libc-diag.h>
+
+__BEGIN_DECLS
+
+DIR *xopendir (const char *path);
+DIR *xfdopendir (int fd);
+void xclosedir (DIR *);
+
+void *support_readdir_check (const char *, void *);
+#define xreaddir(d)                                                     \
+  ((struct dirent *) support_readdir_check ("readdir",                  \
+                                            (errno = 0, readdir ((d)))))
+#define xreaddir64(d)                                                   \
+  ((struct dirent64 *) support_readdir_check ("readdir64",              \
+                                              (errno = 0, readdir64 ((d)))))
+
+int support_readdir_r_check (const char *, int);
+
+/* The functions readdir_r, readdir64_r were deprecated in glibc 2.24.  */
+DIAG_PUSH_NEEDS_COMMENT;
+DIAG_IGNORE_NEEDS_COMMENT (4.9, "-Wdeprecated-declarations");
+#define xreaddir_r(d, e, r)                                             \
+  (support_readdir_r_check ("readdir_r", readdir_r ((d), (e), (r))))
+#define xreaddir64_r(d, e, r) \
+  (support_readdir_r_check ("readdir64_r", readdir64_r ((d), (e), (r))))
+DIAG_POP_NEEDS_COMMENT;
+
+__END_DECLS
+
+#endif /* SUPPORT_XDIRENT_H */
diff --git a/support/xfdopendir.c b/support/xfdopendir.c
new file mode 100644
index 0000000000..d881d28c73
--- /dev/null
+++ b/support/xfdopendir.c
@@ -0,0 +1,30 @@ 
+/* Error-checking wrapper for fdopendir.
+   Copyright (C) 2024 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <support/xdirent.h>
+
+#include <support/check.h>
+
+DIR *
+xfdopendir (int fd)
+{
+  DIR *result = fdopendir (fd);
+  if (result == NULL)
+    FAIL_EXIT1 ("fdopendir (%d): %m", fd);
+  return result;
+}
diff --git a/support/xopendir.c b/support/xopendir.c
new file mode 100644
index 0000000000..e4aee07fee
--- /dev/null
+++ b/support/xopendir.c
@@ -0,0 +1,30 @@ 
+/* Error-checking wrapper for opendir.
+   Copyright (C) 2024 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <support/xdirent.h>
+
+#include <support/check.h>
+
+DIR *
+xopendir (const char *path)
+{
+  DIR *result = opendir (path);
+  if (result == NULL)
+    FAIL_EXIT1 ("opendir (\"%s\"): %m", path);
+  return result;
+}