diff --git a/stdio-common/Makefile b/stdio-common/Makefile
index 948d960ccc..3c3d8a2bcd 100644
--- a/stdio-common/Makefile
+++ b/stdio-common/Makefile
@@ -216,6 +216,7 @@ tests := \
   tst-fmemopen4 \
   tst-fphex \
   tst-fphex-wide \
+  tst-freopen2 \
   tst-fseek \
   tst-fwrite \
   tst-getline \
diff --git a/stdio-common/tst-freopen2.c b/stdio-common/tst-freopen2.c
new file mode 100644
index 0000000000..4a5a3c016e
--- /dev/null
+++ b/stdio-common/tst-freopen2.c
@@ -0,0 +1,446 @@
+/* Test freopen.
+   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 <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <wchar.h>
+
+#include <support/check.h>
+#include <support/file_contents.h>
+#include <support/support.h>
+#include <support/temp_file.h>
+#include <support/test-driver.h>
+#include <support/xstdio.h>
+
+int
+do_test (void)
+{
+  char *temp_dir = support_create_temp_directory ("tst-freopen2");
+  char *file1 = xasprintf ("%s/file1", temp_dir);
+  support_write_file_string (file1, "file1");
+  add_temp_file (file1);
+  char *file2 = xasprintf ("%s/file2", temp_dir);
+  support_write_file_string (file2, "file2");
+  add_temp_file (file2);
+  char *file3 = xasprintf ("%s/file3", temp_dir);
+  char *file4 = xasprintf ("%s/file4", temp_dir);
+  char *file_nodir = xasprintf ("%s/nodir/file", temp_dir);
+  char *file1a = xasprintf ("%s/file1a", temp_dir);
+  FILE *fp;
+  int ret;
+  wint_t wc;
+  int fd;
+
+  /* Test each pair of old and new modes from r w a.  */
+
+  verbose_printf ("Testing r -> r\n");
+  fp = xfopen (file1, "r");
+  fp = freopen (file2, "r", fp);
+  TEST_VERIFY_EXIT (fp != NULL);
+  TEST_COMPARE_FILE_STRING (fp, "file2");
+  xfclose (fp);
+
+  verbose_printf ("Testing r -> w\n");
+  fp = xfopen (file1, "r");
+  fp = freopen (file2, "w", fp);
+  TEST_VERIFY_EXIT (fp != NULL);
+  ret = fputs ("File2new", fp);
+  TEST_VERIFY (ret >= 0);
+  xfclose (fp);
+  TEST_OPEN_AND_COMPARE_FILE_STRING (file2, "File2new");
+
+  verbose_printf ("Testing r -> a\n");
+  fp = xfopen (file1, "r");
+  fp = freopen (file2, "a", fp);
+  TEST_VERIFY_EXIT (fp != NULL);
+  ret = fputs ("3", fp);
+  TEST_VERIFY (ret >= 0);
+  xfclose (fp);
+  TEST_OPEN_AND_COMPARE_FILE_STRING (file2, "File2new3");
+
+  verbose_printf ("Testing w -> r\n");
+  fp = xfopen (file1, "w");
+  fp = freopen (file2, "r", fp);
+  TEST_VERIFY_EXIT (fp != NULL);
+  TEST_COMPARE_FILE_STRING (fp, "File2new3");
+  xfclose (fp);
+
+  verbose_printf ("Testing w -> w\n");
+  fp = xfopen (file1, "w");
+  fp = freopen (file2, "w", fp);
+  TEST_VERIFY_EXIT (fp != NULL);
+  ret = fputs ("next", fp);
+  TEST_VERIFY (ret >= 0);
+  xfclose (fp);
+  TEST_OPEN_AND_COMPARE_FILE_STRING (file2, "next");
+
+  verbose_printf ("Testing w -> a\n");
+  fp = xfopen (file1, "w");
+  fp = freopen (file2, "a", fp);
+  TEST_VERIFY_EXIT (fp != NULL);
+  ret = fputs ("4", fp);
+  TEST_VERIFY (ret >= 0);
+  xfclose (fp);
+  TEST_OPEN_AND_COMPARE_FILE_STRING (file2, "next4");
+
+  verbose_printf ("Testing a -> r\n");
+  fp = xfopen (file1, "a");
+  fp = freopen (file2, "r", fp);
+  TEST_VERIFY_EXIT (fp != NULL);
+  TEST_COMPARE_FILE_STRING (fp, "next4");
+  xfclose (fp);
+
+  verbose_printf ("Testing a -> w\n");
+  fp = xfopen (file1, "a");
+  fp = freopen (file2, "w", fp);
+  TEST_VERIFY_EXIT (fp != NULL);
+  ret = fputs ("another", fp);
+  TEST_VERIFY (ret >= 0);
+  xfclose (fp);
+  TEST_OPEN_AND_COMPARE_FILE_STRING (file2, "another");
+
+  verbose_printf ("Testing a -> a\n");
+  fp = xfopen (file1, "w");
+  fp = freopen (file2, "a", fp);
+  TEST_VERIFY_EXIT (fp != NULL);
+  ret = fputs ("5", fp);
+  TEST_VERIFY (ret >= 0);
+  xfclose (fp);
+  TEST_OPEN_AND_COMPARE_FILE_STRING (file2, "another5");
+
+  /* Test changing to/from b (binary, no-op).  */
+
+  verbose_printf ("Testing rb -> r\n");
+  fp = xfopen (file1, "rb");
+  fp = freopen (file2, "r", fp);
+  TEST_VERIFY_EXIT (fp != NULL);
+  TEST_COMPARE_FILE_STRING (fp, "another5");
+  xfclose (fp);
+
+  verbose_printf ("Testing r -> rb\n");
+  fp = xfopen (file1, "r");
+  fp = freopen (file2, "rb", fp);
+  TEST_VERIFY_EXIT (fp != NULL);
+  TEST_COMPARE_FILE_STRING (fp, "another5");
+  xfclose (fp);
+
+  /* Test changing to/from + (read-and-write).  */
+
+  verbose_printf ("Testing r -> w+\n");
+  fp = xfopen (file1, "r");
+  fp = freopen (file2, "w+", fp);
+  TEST_VERIFY_EXIT (fp != NULL);
+  ret = fputs ("latest", fp);
+  TEST_VERIFY (ret >= 0);
+  ret = fseek (fp, 0, SEEK_SET);
+  TEST_COMPARE (ret, 0);
+  TEST_COMPARE_FILE_STRING (fp, "latest");
+  xfclose (fp);
+  TEST_OPEN_AND_COMPARE_FILE_STRING (file2, "latest");
+
+  verbose_printf ("Testing w -> a+\n");
+  fp = xfopen (file1, "w");
+  fp = freopen (file2, "a+", fp);
+  TEST_VERIFY_EXIT (fp != NULL);
+  ret = fputs ("suffix", fp);
+  TEST_VERIFY (ret >= 0);
+  ret = fseek (fp, 0, SEEK_SET);
+  TEST_COMPARE (ret, 0);
+  TEST_COMPARE_FILE_STRING (fp, "latestsuffix");
+  xfclose (fp);
+  TEST_OPEN_AND_COMPARE_FILE_STRING (file2, "latestsuffix");
+
+  verbose_printf ("Testing a -> r+\n");
+  fp = xfopen (file1, "a");
+  fp = freopen (file2, "r+", fp);
+  TEST_VERIFY_EXIT (fp != NULL);
+  TEST_COMPARE_FILE_STRING (fp, "latestsuffix");
+  ret = fseek (fp, 0, SEEK_SET);
+  TEST_COMPARE (ret, 0);
+  ret = fputs ("new", fp);
+  TEST_VERIFY (ret >= 0);
+  xfclose (fp);
+  TEST_OPEN_AND_COMPARE_FILE_STRING (file2, "newestsuffix");
+
+  verbose_printf ("Testing r+ -> w\n");
+  fp = xfopen (file1, "r+");
+  fp = freopen (file2, "w", fp);
+  TEST_VERIFY_EXIT (fp != NULL);
+  ret = fputs ("plusto", fp);
+  TEST_VERIFY (ret >= 0);
+  ret = fseek (fp, 0, SEEK_SET);
+  TEST_COMPARE (ret, 0);
+  errno = 0;
+  TEST_COMPARE (fgetc (fp), EOF);
+  TEST_COMPARE (errno, EBADF);
+  clearerr (fp);
+  xfclose (fp);
+  TEST_OPEN_AND_COMPARE_FILE_STRING (file2, "plusto");
+
+  verbose_printf ("Testing w+ -> a\n");
+  fp = xfopen (file1, "w+");
+  fp = freopen (file2, "a", fp);
+  TEST_VERIFY_EXIT (fp != NULL);
+  ret = fputs ("more", fp);
+  TEST_VERIFY (ret >= 0);
+  ret = fseek (fp, 0, SEEK_SET);
+  TEST_COMPARE (ret, 0);
+  errno = 0;
+  TEST_COMPARE (fgetc (fp), EOF);
+  TEST_COMPARE (errno, EBADF);
+  clearerr (fp);
+  xfclose (fp);
+  TEST_OPEN_AND_COMPARE_FILE_STRING (file2, "plustomore");
+
+  verbose_printf ("Testing a+ -> r\n");
+  fp = xfopen (file1, "a+");
+  fp = freopen (file2, "rr", fp);
+  TEST_VERIFY_EXIT (fp != NULL);
+  TEST_COMPARE_FILE_STRING (fp, "plustomore");
+  ret = fputs ("2", fp);
+  TEST_COMPARE (ret, EOF);
+  clearerr (fp);
+  xfclose (fp);
+  TEST_OPEN_AND_COMPARE_FILE_STRING (file2, "plustomore");
+
+  /* Test changing to/from e (FD_CLOEXEC).  */
+
+  verbose_printf ("Testing re -> r\n");
+  fp = xfopen (file1, "re");
+  ret = fcntl (fileno (fp), F_GETFD);
+  TEST_VERIFY (ret != -1);
+  TEST_COMPARE (ret & FD_CLOEXEC, FD_CLOEXEC);
+  fp = freopen (file2, "r", fp);
+  TEST_VERIFY_EXIT (fp != NULL);
+  ret = fcntl (fileno (fp), F_GETFD);
+  TEST_VERIFY (ret != -1);
+#if 0 /* Fails to clear FD_CLOEXEC.  */
+  TEST_COMPARE (ret & FD_CLOEXEC, 0);
+#endif
+  TEST_COMPARE_FILE_STRING (fp, "plustomore");
+  xfclose (fp);
+
+  verbose_printf ("Testing r -> re\n");
+  fp = xfopen (file1, "r");
+  ret = fcntl (fileno (fp), F_GETFD);
+  TEST_VERIFY (ret != -1);
+  TEST_COMPARE (ret & FD_CLOEXEC, 0);
+  fp = freopen (file2, "re", fp);
+  TEST_VERIFY_EXIT (fp != NULL);
+  ret = fcntl (fileno (fp), F_GETFD);
+  TEST_VERIFY (ret != -1);
+  TEST_COMPARE (ret & FD_CLOEXEC, FD_CLOEXEC);
+  TEST_COMPARE_FILE_STRING (fp, "plustomore");
+  xfclose (fp);
+
+  /* Test changing to/from m (mmap) (a no-op as far as testing
+     semantics is concerned).  */
+
+  verbose_printf ("Testing rm -> r\n");
+  fp = xfopen (file1, "rm");
+  fp = freopen (file2, "r", fp);
+  TEST_VERIFY_EXIT (fp != NULL);
+  TEST_COMPARE_FILE_STRING (fp, "plustomore");
+  xfclose (fp);
+
+  verbose_printf ("Testing r -> rm\n");
+  fp = xfopen (file1, "r");
+  fp = freopen (file2, "rm", fp);
+  TEST_VERIFY_EXIT (fp != NULL);
+  TEST_COMPARE_FILE_STRING (fp, "plustomore");
+  xfclose (fp);
+
+  /* Test changing to/from x (O_EXCL).  */
+
+  verbose_printf ("Testing wx -> w\n");
+  fp = xfopen (file3, "wx");
+  add_temp_file (file3);
+  fp = freopen (file2, "w", fp);
+  TEST_VERIFY_EXIT (fp != NULL);
+  ret = fputs ("wxtow", fp);
+  TEST_VERIFY (ret >= 0);
+  xfclose (fp);
+  TEST_OPEN_AND_COMPARE_FILE_STRING (file2, "wxtow");
+
+  verbose_printf ("Testing w -> wx (file does not exist)\n");
+  fp = xfopen (file1, "w");
+  fp = freopen (file4, "wx", fp);
+  TEST_VERIFY_EXIT (fp != NULL);
+  add_temp_file (file4);
+  ret = fputs ("wtowx", fp);
+  TEST_VERIFY (ret >= 0);
+  xfclose (fp);
+  TEST_OPEN_AND_COMPARE_FILE_STRING (file4, "wtowx");
+
+  verbose_printf ("Testing w -> wx (file exists)\n");
+  fp = xfopen (file1, "w");
+  fp = freopen (file4, "wx", fp);
+  TEST_VERIFY (fp == NULL);
+
+  /* Test with ,ccs=CHARSET.  */
+
+  verbose_printf ("testing w,ccs=utf-8 -> r\n");
+  fp = xfopen (file1, "w,ccs=utf-8");
+  ret = fputws (L"\xc0\xc1", fp);
+  TEST_VERIFY (ret >= 0);
+  fp = freopen (file2, "r", fp);
+  TEST_VERIFY_EXIT (fp != NULL);
+  TEST_COMPARE_FILE_STRING (fp, "wxtow");
+  xfclose (fp);
+
+  verbose_printf ("testing w,ccs=iso-8859-1 -> r,ccs=utf-8\n");
+  fp = xfopen (file2, "w,ccs=iso-8859-1");
+  ret = fputws (L"\xc0\xc1", fp);
+  TEST_VERIFY (ret >= 0);
+#if 0 /* Doesn't work (bug 23675).  */
+  fp = freopen (file1, "r,ccs=utf-8", fp);
+  TEST_VERIFY_EXIT (fp != NULL);
+#else /* Works instead.  */
+  xfclose (fp);
+  fp = xfopen (file1, "r,ccs=utf-8");
+#endif
+  wc = fgetwc (fp);
+  TEST_COMPARE (wc, (wint_t) 0xc0);
+  wc = fgetwc (fp);
+  TEST_COMPARE (wc, (wint_t) 0xc1);
+  wc = fgetwc (fp);
+  TEST_COMPARE (wc, WEOF);
+  xfclose (fp);
+
+  verbose_printf ("testing r,ccs=utf-8 -> r\n");
+  fp = xfopen (file1, "r,ccs=utf-8");
+  fp = freopen (file1, "r", fp);
+  TEST_VERIFY_EXIT (fp != NULL);
+  TEST_COMPARE_FILE_STRING (fp, "\u00c0\u00c1");
+  xfclose (fp);
+
+  /* Test old file is closed even when opening the new file fails.  */
+
+  verbose_printf ("testing r -> r (opening new file fails)\n");
+  fp = xfopen (file1, "r");
+  fd = fileno (fp);
+  fp = freopen (file_nodir, "r", fp);
+  TEST_VERIFY (fp == NULL);
+  errno = 0;
+  ret = fcntl (fd, F_GETFL);
+  TEST_COMPARE (ret, -1);
+  TEST_COMPARE (errno, EBADF);
+
+  /* Test that errors closing the old file are ignored.  */
+
+  verbose_printf ("testing errors closing old file ignored\n");
+  fp = xfopen ("/dev/full", "w");
+  fputc ('x', fp);
+  fp = freopen (file1, "r", fp);
+  TEST_VERIFY_EXIT (fp != NULL);
+  TEST_COMPARE_FILE_STRING (fp, "\u00c0\u00c1");
+  xfclose (fp);
+
+  /* Test that error / EOF state from the old file are cleared.  */
+
+  verbose_printf ("testing error state from old file cleared\n");
+  fp = xfopen ("/dev/full", "w");
+  fputc ('x', fp);
+  fflush (fp);
+  TEST_VERIFY (ferror (fp));
+  TEST_VERIFY (!feof (fp));
+  fp = freopen (file2, "w", fp);
+  TEST_VERIFY_EXIT (fp != NULL);
+  TEST_VERIFY (!ferror (fp));
+  TEST_VERIFY (!feof (fp));
+  xfclose (fp);
+
+  verbose_printf ("testing EOF state from old file cleared\n");
+  fp = xfopen ("/dev/null", "r");
+  fgetc (fp);
+  TEST_VERIFY (!ferror (fp));
+  TEST_VERIFY (feof (fp));
+  fp = freopen (file2, "r", fp);
+  TEST_VERIFY_EXIT (fp != NULL);
+  TEST_VERIFY (!ferror (fp));
+  TEST_VERIFY (!feof (fp));
+  xfclose (fp);
+
+  /* Test freopen with NULL, same mode (should flush content and reset
+     file offset).  */
+
+  verbose_printf ("testing freopen with NULL, same mode\n");
+  fp = xfopen (file1, "r+");
+  ret = fputs ("same mode", fp);
+  TEST_VERIFY (ret >= 0);
+  fp = freopen (NULL, "r+", fp);
+  TEST_VERIFY_EXIT (fp != NULL);
+  TEST_COMPARE_FILE_STRING (fp, "same mode");
+  xfclose (fp);
+
+  /* Test freopen with NULL, different mode.  */
+
+  verbose_printf ("testing freopen with NULL, different mode\n");
+  fp = xfopen (file1, "w");
+  ret = fputs ("different mode", fp);
+  TEST_VERIFY (ret >= 0);
+  fp = freopen (NULL, "r", fp);
+  TEST_VERIFY_EXIT (fp != NULL);
+  TEST_COMPARE_FILE_STRING (fp, "different mode");
+  xfclose (fp);
+
+  /* Test freopen with NULL, renamed file.  */
+
+  verbose_printf ("testing freopen with NULL, renamed file\n");
+  fp = xfopen (file1, "r+");
+  ret = fputs ("file has been renamed", fp);
+  TEST_VERIFY (ret >= 0);
+  ret = rename (file1, file1a);
+  TEST_COMPARE (ret, 0);
+  fp = freopen (NULL, "r+", fp);
+  TEST_VERIFY_EXIT (fp != NULL);
+  TEST_COMPARE_FILE_STRING (fp, "file has been renamed");
+  xfclose (fp);
+  ret = rename (file1a, file1);
+  TEST_COMPARE (ret, 0);
+
+  /* Test freopen with NULL, deleted file.  */
+
+  verbose_printf ("testing freopen with NULL, deleted file\n");
+  fp = xfopen (file1, "r+");
+  ret = fputs ("file has now been deleted", fp);
+  TEST_VERIFY (ret >= 0);
+  ret = remove (file1);
+  TEST_COMPARE (ret, 0);
+  fp = freopen (NULL, "r+", fp);
+  TEST_VERIFY_EXIT (fp != NULL);
+  TEST_COMPARE_FILE_STRING (fp, "file has now been deleted");
+  xfclose (fp);
+  /* Recreate the file so it is present when expected for temporary
+     file deletion.  */
+  support_write_file_string (file1, "file1");
+
+  free (temp_dir);
+  free (file1);
+  free (file2);
+  free (file3);
+  free (file4);
+  free (file_nodir);
+  free (file1a);
+  return 0;
+}
+
+#include <support/test-driver.c>
diff --git a/support/Makefile b/support/Makefile
index 6e3c55394f..26bd3d38e4 100644
--- a/support/Makefile
+++ b/support/Makefile
@@ -49,6 +49,8 @@ libsupport-routines = \
   support_check_stat_fd \
   support_check_stat_path \
   support_chroot \
+  support_compare_file_bytes \
+  support_compare_file_string \
   support_copy_file \
   support_copy_file_range \
   support_create_timer \
@@ -65,6 +67,8 @@ libsupport-routines = \
   support_isolate_in_subprocess \
   support_mutex_pi_monotonic \
   support_need_proc \
+  support_open_and_compare_file_bytes \
+  support_open_and_compare_file_string \
   support_openpty \
   support_path_support_time64 \
   support_paths \
diff --git a/support/file_contents.h b/support/file_contents.h
new file mode 100644
index 0000000000..eea05eebc0
--- /dev/null
+++ b/support/file_contents.h
@@ -0,0 +1,56 @@
+/* Functionality for checking file contents.
+   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_FILE_CONTENTS_H
+#define SUPPORT_FILE_CONTENTS_H
+
+#include <support/check.h>
+#include <stdio.h>
+
+__BEGIN_DECLS
+
+/* Check that an already-open file has exactly the given bytes,
+   starting at the current offset.  */
+int support_compare_file_bytes (FILE *fp, const char *contents, size_t length);
+
+/* Check that an already-open file has exactly the given string as
+   contents, starting at the current offset.  */
+int support_compare_file_string (FILE *fp, const char *contents);
+
+/* Check that a not-currently-open file has exactly the given
+   bytes.  */
+int support_open_and_compare_file_bytes (const char *file,
+					 const char *contents,
+					 size_t length);
+
+/* Check that a not-currently-open file has exactly the given string
+   as contents, starting at the current offset.  */
+int support_open_and_compare_file_string (const char *file,
+					  const char *contents);
+
+/* Compare bytes read from an open file with the given string.  */
+#define TEST_COMPARE_FILE_STRING(FP, CONTENTS)			\
+  TEST_COMPARE (support_compare_file_string (FP, CONTENTS), 0)
+
+/* Open a file and compare bytes read from it with the given string.  */
+#define TEST_OPEN_AND_COMPARE_FILE_STRING(FILE, CONTENTS)		\
+  TEST_COMPARE (support_open_and_compare_file_string (FILE, CONTENTS), 0)
+
+__END_DECLS
+
+#endif /* SUPPORT_FILE_CONTENTS_H */
diff --git a/support/support_compare_file_bytes.c b/support/support_compare_file_bytes.c
new file mode 100644
index 0000000000..6e3b51b0a0
--- /dev/null
+++ b/support/support_compare_file_bytes.c
@@ -0,0 +1,42 @@
+/* Compare bytes from an open file.
+   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 <stdio.h>
+
+#include <support/file_contents.h>
+
+/* Check that an already-open file has exactly the given bytes,
+   starting at the current offset.  */
+
+int
+support_compare_file_bytes (FILE *fp, const char *contents, size_t length)
+{
+  int c;
+  while (length > 0)
+    {
+      c = getc (fp);
+      if (c == EOF || (unsigned char) c != (unsigned char) contents[0])
+	return 1;
+      contents++;
+      length--;
+    }
+  c = getc (fp);
+  if (c != EOF)
+    return 1;
+  return 0;
+}
diff --git a/support/support_compare_file_string.c b/support/support_compare_file_string.c
new file mode 100644
index 0000000000..04513c3af1
--- /dev/null
+++ b/support/support_compare_file_string.c
@@ -0,0 +1,28 @@
+/* Compare string from an open file.
+   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 <stdio.h>
+#include <string.h>
+
+#include <support/file_contents.h>
+
+int
+support_compare_file_string (FILE *fp, const char *contents)
+{
+  return support_compare_file_bytes (fp, contents, strlen (contents));
+}
diff --git a/support/support_open_and_compare_file_bytes.c b/support/support_open_and_compare_file_bytes.c
new file mode 100644
index 0000000000..f804ed8e46
--- /dev/null
+++ b/support/support_open_and_compare_file_bytes.c
@@ -0,0 +1,33 @@
+/* Compare bytes from a file.
+   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/file_contents.h>
+#include <support/xstdio.h>
+
+/* Check that a not-currently-open file has exactly the given
+   bytes.  */
+
+int
+support_open_and_compare_file_bytes (const char *file, const char *contents,
+				     size_t length)
+{
+  FILE *fp = xfopen (file, "r");
+  int ret = support_compare_file_bytes (fp, contents, length);
+  xfclose (fp);
+  return ret;
+}
diff --git a/support/support_open_and_compare_file_string.c b/support/support_open_and_compare_file_string.c
new file mode 100644
index 0000000000..2b596d4c88
--- /dev/null
+++ b/support/support_open_and_compare_file_string.c
@@ -0,0 +1,32 @@
+/* Compare string from a file.
+   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 <string.h>
+
+#include <support/file_contents.h>
+#include <support/xstdio.h>
+
+/* Check that a not-currently-open file has exactly the given string
+   as contents, starting at the current offset.  */
+
+int
+support_open_and_compare_file_string (const char *file, const char *contents)
+{
+  return support_open_and_compare_file_bytes (file, contents,
+					      strlen (contents));
+}
