Add freopen special-case tests: chroot, EFBIG, stdin/stdout/stderr

Add tests of special cases for freopen that were omitted from the more
general tests of different modes and similar issues.  The special
cases in the three tests here are logically unconnected, it was simply
convenient to put these tests in one patch.

* Test freopen with a NULL path to the new file, in a chroot.  Rather
  than asserting that this fails (logically, failure in this case is
  an implementation detail; it's not required for freopen to rely on
  /proc), verify that either it fails (without memory leaks) or that
  it succeeds and behaves as expected on success.  There is no check
  for file descriptor leaks because the machinery for that also
  depends on /proc, so can't be used in a chroot.

* Test that freopen and freopen64 are genuinely different in
  configurations with 32-bit off_t by checking for an EFBIG trying to
  write past 2GB in a file opened with freopen in such a configuration
  but no error with 64-bit off_t or when opening with freopen64.

* Test freopen of stdin, stdout and stderr.

Tested for x86_64 and x86.

stdio-common/Makefile

@@ -219,8 +219,13 @@ tests := \
   tst-fphex-wide \
   tst-freopen2 \
   tst-freopen3 \
+  tst-freopen4 \
+  tst-freopen5 \
+  tst-freopen6 \
   tst-freopen64-2 \
   tst-freopen64-3 \
+  tst-freopen64-4 \
+  tst-freopen64-6 \
   tst-fseek \
   tst-fwrite \
   tst-fwrite-memstrm \
@@ -324,8 +329,13 @@ ifneq ($(PERL),no)
 tests-special += \
   $(objpfx)tst-freopen2-mem.out \
   $(objpfx)tst-freopen3-mem.out \
+  $(objpfx)tst-freopen4-mem.out \
+  $(objpfx)tst-freopen5-mem.out \
+  $(objpfx)tst-freopen6-mem.out \
   $(objpfx)tst-freopen64-2-mem.out \
   $(objpfx)tst-freopen64-3-mem.out \
+  $(objpfx)tst-freopen64-4-mem.out \
+  $(objpfx)tst-freopen64-6-mem.out \
   $(objpfx)tst-getline-enomem-mem.out \
   $(objpfx)tst-getline-mem.out \
   $(objpfx)tst-printf-bz18872-mem.out \
@@ -341,10 +351,20 @@ generated += \
   tst-freopen2.mtrace \
   tst-freopen3-mem.out \
   tst-freopen3.mtrace \
+  tst-freopen4-mem.out \
+  tst-freopen4.mtrace \
+  tst-freopen5-mem.out \
+  tst-freopen5.mtrace \
+  tst-freopen6-mem.out \
+  tst-freopen6.mtrace \
   tst-freopen64-2-mem.out \
   tst-freopen64-2.mtrace \
   tst-freopen64-3-mem.out \
   tst-freopen64-3.mtrace \
+  tst-freopen64-4-mem.out \
+  tst-freopen64-4.mtrace \
+  tst-freopen64-6-mem.out \
+  tst-freopen64-6.mtrace \
   tst-getline-enomem-mem.out \
   tst-getline-enomem.mtrace \
   tst-getline-mem.out \
@@ -476,6 +496,21 @@ tst-freopen3-ENV = \
 tst-freopen64-3-ENV = \
   MALLOC_TRACE=$(objpfx)tst-freopen64-3.mtrace \
   LD_PRELOAD=$(common-objpfx)malloc/libc_malloc_debug.so
+tst-freopen4-ENV = \
+  MALLOC_TRACE=$(objpfx)tst-freopen4.mtrace \
+  LD_PRELOAD=$(common-objpfx)malloc/libc_malloc_debug.so
+tst-freopen64-4-ENV = \
+  MALLOC_TRACE=$(objpfx)tst-freopen64-4.mtrace \
+  LD_PRELOAD=$(common-objpfx)malloc/libc_malloc_debug.so
+tst-freopen5-ENV = \
+  MALLOC_TRACE=$(objpfx)tst-freopen5.mtrace \
+  LD_PRELOAD=$(common-objpfx)malloc/libc_malloc_debug.so
+tst-freopen6-ENV = \
+  MALLOC_TRACE=$(objpfx)tst-freopen6.mtrace \
+  LD_PRELOAD=$(common-objpfx)malloc/libc_malloc_debug.so
+tst-freopen64-6-ENV = \
+  MALLOC_TRACE=$(objpfx)tst-freopen64-6.mtrace \
+  LD_PRELOAD=$(common-objpfx)malloc/libc_malloc_debug.so
 
 $(objpfx)tst-unbputc.out: tst-unbputc.sh $(objpfx)tst-unbputc
 	$(SHELL) $< $(common-objpfx) '$(test-program-prefix)'; \

stdio-common/tst-freopen4-main.c

@@ -0,0 +1,100 @@
+/* Test freopen in chroot.
+   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 <mcheck.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include <support/check.h>
+#include <support/file_contents.h>
+#include <support/namespace.h>
+#include <support/support.h>
+#include <support/temp_file.h>
+#include <support/test-driver.h>
+#include <support/xstdio.h>
+#include <support/xunistd.h>
+
+int
+do_test (void)
+{
+  mtrace ();
+  char *temp_dir = support_create_temp_directory ("tst-freopen4");
+  FILE *fp;
+  int ret;
+
+  /* These chroot tests verify that either reopening a renamed or
+     deleted file works even in the absence of /proc, or that it fails
+     (without memory leaks); thus, for example, such reopening does
+     not crash in the absence of /proc.  */
+
+  support_become_root ();
+  if (!support_can_chroot ())
+    return EXIT_UNSUPPORTED;
+  xchroot (temp_dir);
+
+  /* Test freopen with NULL, renamed file.  This verifies that
+     reopening succeeds (and resets the file position indicator to
+     start of file) even when the original path could no longer be
+     opened, or fails without a memory leak.  (It is not possible to
+     use <support/descriptors.h> to test for file descriptor leaks
+     here, because that also depends on /proc.)  */
+
+  verbose_printf ("testing freopen with NULL, renamed file\n");
+  fp = xfopen ("/file1", "w+");
+  ret = fputs ("file has been renamed", fp);
+  TEST_VERIFY (ret >= 0);
+  ret = rename ("/file1", "/file1a");
+  TEST_COMPARE (ret, 0);
+  fp = FREOPEN (NULL, "r+", fp);
+  if (fp != NULL)
+    {
+      puts ("freopen of renamed file succeeded");
+      TEST_COMPARE_FILE_STRING (fp, "file has been renamed");
+      xfclose (fp);
+    }
+  else
+    puts ("freopen of renamed file failed (OK)");
+  ret = rename ("/file1a", "/file1");
+  TEST_COMPARE (ret, 0);
+
+  /* Test freopen with NULL, deleted file.  This verifies that
+     reopening succeeds (and resets the file position indicator to
+     start of file) even when the original path could no longer be
+     opened, or fails without a memory leak.  */
+
+  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);
+  if (fp != NULL)
+    {
+      puts ("freopen of deleted file succeeded");
+      TEST_COMPARE_FILE_STRING (fp, "file has now been deleted");
+      xfclose (fp);
+    }
+  else
+    puts ("freopen of deleted file failed (OK)");
+
+  free (temp_dir);
+  return 0;
+}
+
+#include <support/test-driver.c>

stdio-common/tst-freopen4.c

@@ -0,0 +1,2 @@
+#define FREOPEN freopen
+#include <tst-freopen4-main.c>

stdio-common/tst-freopen5.c

@@ -0,0 +1,144 @@
+/* Test freopen and freopen64 with large offsets.
+   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 <mcheck.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include <support/check.h>
+#include <support/descriptors.h>
+#include <support/support.h>
+#include <support/temp_file.h>
+#include <support/test-driver.h>
+#include <support/xstdio.h>
+
+#define START_TEST(DESC)			\
+  do						\
+    {						\
+      fds = support_descriptors_list ();	\
+      verbose_printf (DESC);			\
+    }						\
+  while (0)
+
+#define END_TEST				\
+  do						\
+    {						\
+      support_descriptors_check (fds);		\
+      support_descriptors_free (fds);		\
+    }						\
+  while (0)
+
+int
+do_test (void)
+{
+  mtrace ();
+  struct support_descriptors *fds;
+  FILE *fp;
+  int ret;
+
+  char *temp_dir = support_create_temp_directory ("tst-freopen5");
+  /* This file is removed at the end of each test rather than left
+     around between tests to avoid problems with subsequent tests
+     reopening it as a large (2GB + 1 byte) file.  */
+  char *file1 = xasprintf ("%s/file1", temp_dir);
+
+  /* fopen with freopen64: large offsets OK.  */
+  START_TEST ("testing fopen with freopen64\n");
+  fp = fopen ("/dev/null", "r");
+  TEST_VERIFY_EXIT (fp != NULL);
+  fp = freopen64 (file1, "w", fp);
+  TEST_VERIFY_EXIT (fp != NULL);
+  setbuf (fp, NULL);
+  ret = fseeko64 (fp, 1LL << 32, SEEK_SET);
+  TEST_COMPARE (ret, 0);
+  ret = fputc ('x', fp);
+  TEST_COMPARE (ret, 'x');
+  xfclose (fp);
+  ret = remove (file1);
+  TEST_COMPARE (ret, 0);
+  END_TEST;
+
+  /* fopen64 with freopen64: large offsets OK.  */
+  START_TEST ("testing fopen64 with freopen64\n");
+  fp = fopen64 ("/dev/null", "r");
+  TEST_VERIFY_EXIT (fp != NULL);
+  fp = freopen64 (file1, "w", fp);
+  TEST_VERIFY_EXIT (fp != NULL);
+  setbuf (fp, NULL);
+  ret = fseeko64 (fp, 1LL << 32, SEEK_SET);
+  TEST_COMPARE (ret, 0);
+  ret = fputc ('x', fp);
+  TEST_COMPARE (ret, 'x');
+  xfclose (fp);
+  ret = remove (file1);
+  TEST_COMPARE (ret, 0);
+  END_TEST;
+
+  /* fopen with freopen: large offsets not OK on 32-bit systems.  */
+  START_TEST ("testing fopen with freopen\n");
+  fp = fopen ("/dev/null", "r");
+  TEST_VERIFY_EXIT (fp != NULL);
+  fp = freopen (file1, "w", fp);
+  TEST_VERIFY_EXIT (fp != NULL);
+  setbuf (fp, NULL);
+  ret = fseeko64 (fp, 1LL << 32, SEEK_SET);
+  TEST_COMPARE (ret, 0);
+  errno = 0;
+  ret = fputc ('x', fp);
+  if (sizeof (off_t) == 4)
+    {
+      TEST_COMPARE (ret, EOF);
+      TEST_COMPARE (errno, EFBIG);
+    }
+  else
+    TEST_COMPARE (ret, 'x');
+  fclose (fp);
+  ret = remove (file1);
+  TEST_COMPARE (ret, 0);
+  END_TEST;
+
+  /* fopen64 with freopen: large offsets not OK on 32-bit systems.  */
+  START_TEST ("testing fopen64 with freopen\n");
+  fp = fopen64 ("/dev/null", "r");
+  TEST_VERIFY_EXIT (fp != NULL);
+  fp = freopen (file1, "w", fp);
+  TEST_VERIFY_EXIT (fp != NULL);
+  setbuf (fp, NULL);
+  ret = fseeko64 (fp, 1LL << 32, SEEK_SET);
+  TEST_COMPARE (ret, 0);
+  errno = 0;
+  ret = fputc ('x', fp);
+  if (sizeof (off_t) == 4)
+    {
+      TEST_COMPARE (ret, EOF);
+      TEST_COMPARE (errno, EFBIG);
+    }
+  else
+    TEST_COMPARE (ret, 'x');
+  fclose (fp);
+  ret = remove (file1);
+  TEST_COMPARE (ret, 0);
+  END_TEST;
+
+  free (temp_dir);
+  free (file1);
+  return 0;
+}
+
+#include <support/test-driver.c>

stdio-common/tst-freopen6-main.c

@@ -0,0 +1,98 @@
+/* Test freopen of stdin / stdout / stderr.
+   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 <mcheck.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.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)
+{
+  mtrace ();
+  char *temp_dir = support_create_temp_directory ("tst-freopen6");
+  char *file1 = xasprintf ("%s/file1", temp_dir);
+  support_write_file_string (file1, "file1");
+  add_temp_file (file1);
+  FILE *fp;
+  int ret;
+
+  verbose_printf ("Testing reopening stdin\n");
+  fp = FREOPEN (file1, "r", stdin);
+  TEST_VERIFY_EXIT (fp == stdin);
+  ret = getchar ();
+  TEST_COMPARE (ret, 'f');
+  ret = getchar ();
+  TEST_COMPARE (ret, 'i');
+  ret = getchar ();
+  TEST_COMPARE (ret, 'l');
+  ret = getchar ();
+  TEST_COMPARE (ret, 'e');
+  ret = getchar ();
+  TEST_COMPARE (ret, '1');
+  ret = getchar ();
+  TEST_COMPARE (ret, EOF);
+  xfclose (fp);
+
+  verbose_printf ("Testing reopening stderr\n");
+  fp = FREOPEN (file1, "w+", stderr);
+  TEST_VERIFY_EXIT (fp == stderr);
+  errno = EINVAL;
+  perror ("test");
+  ret = fseek (fp, 0, SEEK_SET);
+  TEST_COMPARE (ret, 0);
+  TEST_COMPARE_FILE_STRING (fp, "test: Invalid argument\n");
+  xfclose (fp);
+
+  verbose_printf ("Testing reopening stdout\n");
+  /* Defer checks until the old stdout has been restored to make it
+     more likely any errors are written to the old stdout (rather than
+     the temporary file used for the redirected stdout).  */
+  int old_stdout = dup (STDOUT_FILENO);
+  TEST_VERIFY_EXIT (old_stdout != -1);
+  int ret_fseek = 0;
+  int ret_compare = 0;
+  fp = FREOPEN (file1, "w+", stdout);
+  int fp_eq_stdout = fp == stdout;
+  if (fp != NULL)
+    {
+      printf ("reopened\n");
+      ret_fseek = fseek (fp, 0, SEEK_SET);
+      ret_compare = support_compare_file_string (fp, "reopened\n");
+    }
+  xfclose (fp);
+  stdout = fdopen (old_stdout, "w");
+  TEST_VERIFY (fp_eq_stdout);
+  TEST_COMPARE (ret_fseek, 0);
+  TEST_COMPARE (ret_compare, 0);
+  xfclose (stdout);
+
+  free (temp_dir);
+  free (file1);
+  return 0;
+}
+
+#include <support/test-driver.c>

stdio-common/tst-freopen6.c

@@ -0,0 +1,2 @@
+#define FREOPEN freopen
+#include <tst-freopen6-main.c>

stdio-common/tst-freopen64-4.c

@@ -0,0 +1,2 @@
+#define FREOPEN freopen64
+#include <tst-freopen4-main.c>

stdio-common/tst-freopen64-6.c

@@ -0,0 +1,2 @@
+#define FREOPEN freopen64
+#include <tst-freopen6-main.c>