support: Add <support/xdirent.h>

Use static functions for readdir/readdir_r, so that
-D_FILE_OFFSET_BITS=64 does not improperly redirect calls to the wrong
implementation.

Reviewed-by: DJ Delorie <dj@redhat.com>

support/Makefile

@@ -77,6 +77,8 @@ 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 \
@@ -119,6 +121,7 @@ libsupport-routines = \
   xclock_settime_time64 \
   xclone \
   xclose \
+  xclosedir \
   xconnect \
   xcopy_file_range \
   xdlfcn \
@@ -126,6 +129,7 @@ libsupport-routines = \
   xdup2 \
   xfchmod \
   xfclose \
+  xfdopendir \
   xfgets \
   xfopen \
   xfork \
@@ -147,6 +151,7 @@ libsupport-routines = \
   xmunmap \
   xnewlocale \
   xopen \
+  xopendir \
   xpipe \
   xpoll \
   xposix_memalign \
@@ -331,6 +336,7 @@ tests = \
   tst-test_compare_string \
   tst-test_compare_string_wide \
   tst-timespec \
+  tst-xdirent \
   tst-xreadlink \
   tst-xsigstack \
   # tests

support/support_readdir_check.c

@@ -0,0 +1,30 @@
+/* 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, int saved_errno)
+{
+  if (result == NULL && errno != 0)
+    FAIL_EXIT1 ("%s: %m", name);
+  errno = saved_errno;
+  return result;
+}

support/support_readdir_r_check.c

@@ -0,0 +1,35 @@
+/* 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, void *buf, void *ptr)
+{
+  if (result != 0)
+    {
+      errno = result;
+      FAIL_EXIT1 ("%s: %m", name);
+    }
+  if (buf != ptr)
+    FAIL_EXIT1 ("%s: buffer pointer and returned pointer differ: %p != %p",
+                name, buf, ptr);
+  return result;
+}

support/tst-xdirent.c

@@ -0,0 +1,76 @@
+/* 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, ".");
+    while (xreaddir (d) != NULL)
+      ;
+    xclosedir (d);
+  }
+
+  {
+    DIR *d = xopendir (".");
+    struct dirent64 *e = xreaddir64 (d);
+    TEST_COMPARE_STRING (e->d_name, ".");
+    while (xreaddir64 (d) != NULL)
+      ;
+    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 = { 0, };
+    TEST_VERIFY (xreaddir_r (d, &buf));
+    TEST_COMPARE_STRING (buf.d_name, ".");
+    while (xreaddir_r (d, &buf))
+      ;
+    xclosedir (d);
+  }
+
+  {
+    DIR *d = xopendir (".");
+    struct dirent64 buf = { 0, };
+    TEST_VERIFY (xreaddir64_r (d, &buf));
+    TEST_COMPARE_STRING (buf.d_name, ".");
+    while (xreaddir64_r (d, &buf))
+      ;
+    xclosedir (d);
+  }
+
+  DIAG_POP_NEEDS_COMMENT;
+
+  return 0;
+}
+
+#include <support/test-driver.c>

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");
+}

support/xdirent.h

@@ -0,0 +1,86 @@
+/* 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>
+#include <stdbool.h>
+#include <stddef.h>
+
+__BEGIN_DECLS
+
+DIR *xopendir (const char *path);
+DIR *xfdopendir (int fd);
+void xclosedir (DIR *);
+
+void *support_readdir_check (const char *, void *, int);
+
+static __attribute__ ((unused)) struct dirent *
+xreaddir (DIR *stream)
+{
+  int saved_errno = errno;
+  errno = 0;
+  struct dirent *result = readdir (stream);
+  return support_readdir_check ("readdir", result, saved_errno);
+}
+
+static __attribute__ ((unused)) struct dirent64 *
+xreaddir64 (DIR *stream)
+{
+  int saved_errno = errno;
+  errno = 0;
+  struct dirent64 *result = readdir64 (stream);
+  return support_readdir_check ("readdir64", result, saved_errno);
+}
+
+/* The functions readdir_r, readdir64_r were deprecated in glibc 2.24.  */
+DIAG_PUSH_NEEDS_COMMENT;
+DIAG_IGNORE_NEEDS_COMMENT (4.9, "-Wdeprecated-declarations");
+
+int support_readdir_r_check (const char *, int, void *, void *);
+
+static __attribute__ ((unused)) bool
+xreaddir_r (DIR *stream, struct dirent *buf)
+{
+  struct dirent *ptr;
+  int ret = readdir_r (stream, buf, &ptr);
+  if (ret == 0 && ptr == NULL)
+    return false;
+  support_readdir_r_check ("readdir_r", ret, buf, ptr);
+  return true;
+}
+
+static __attribute__ ((unused)) bool
+xreaddir64_r (DIR *stream, struct dirent64 *buf)
+{
+  struct dirent64 *ptr;
+  int ret = readdir64_r (stream, buf, &ptr);
+  if (ret == 0 && ptr == NULL)
+    return false;
+  support_readdir_r_check ("readdir64_r", ret, buf, ptr);
+  return true;
+}
+
+DIAG_POP_NEEDS_COMMENT;
+
+__END_DECLS
+
+#endif /* SUPPORT_XDIRENT_H */

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;
+}

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;
+}