stdio-common: Add new test for fdopen

This commit adds fdopen test with all modes.
Reviewed-by: DJ Delorie <dj@redhat.com>

(cherry picked from commit 1d72fa3cfa)

stdio-common/Makefile

@@ -206,6 +206,7 @@ tests := \
   tst-cookie \
   tst-dprintf-length \
   tst-fdopen \
+  tst-fdopen2 \
   tst-ferror \
   tst-fgets \
   tst-fileno \

stdio-common/tst-fdopen2.c

@@ -0,0 +1,246 @@
+/* Test the fdopen function.
+   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 <errno.h>
+#include <fcntl.h>
+#include <support/check.h>
+#include <support/support.h>
+#include <support/xunistd.h>
+#include <support/temp_file.h>
+
+char *tmp_dir;
+char *path_to_file;
+
+void
+prepare_tmp_dir (void)
+{
+  tmp_dir = support_create_temp_directory ("tst-fdopen2");
+  path_to_file = xasprintf ("%s/tst-fdopen2.txt", tmp_dir);
+}
+
+/* open temp file descriptor with mode.  */
+int
+open_tmp_fd (int mode)
+{
+  int fd = xopen (path_to_file, mode, 0644);
+  return fd;
+}
+
+
+/* close and remove temp file with close.  */
+void
+close_tmp_fd (int fd)
+{
+  xclose (fd);
+  xunlink (path_to_file);
+}
+
+/* close and remove temp file with fclose.  */
+void
+close_tmp_fp (FILE *fp)
+{
+  fclose (fp);
+  xunlink (path_to_file);
+}
+
+/* test "w" fdopen mode.  */
+void
+do_test_fdopen_w (void)
+{
+  int fd, ret;
+  FILE *fp;
+  fd = open_tmp_fd (O_WRONLY | O_CREAT | O_TRUNC);
+
+  /* test mode mismatch.  */
+  fp = fdopen (fd, "r");
+  if (fp != NULL || errno != EINVAL)
+    {
+      close_tmp_fd (fd);
+      FAIL_EXIT1 ("fdopen (%d, r) should fail with EINVAL: %m", fd);
+    }
+
+  fp = fdopen (fd, "w");
+  if (fp == NULL)
+    {
+      close_tmp_fd (fd);
+      FAIL_EXIT1 ("fdopen (%d, w): %m", fd);
+    }
+
+  const void *buf = "AAAA";
+  ret = fwrite (buf, 1, 4, fp);
+  if (ret != 4)
+    {
+      close_tmp_fp (fp);
+      FAIL_EXIT1 ("fwrite (): %m");
+    }
+
+  unsigned char buf2[4];
+  rewind (fp);
+  clearerr (fp);
+  /* fread should fail in "w" mode  */
+  ret = fread (buf2, 1, 4, fp);
+  if (ret != 0 || ferror (fp) == 0)
+    {
+      close_tmp_fp (fp);
+      FAIL_EXIT1 ("fread should fail in \"w\" mode");
+    }
+
+  fclose (fp);
+}
+
+/* test "r" fdopen mode. */
+void
+do_test_fdopen_r (void)
+{
+  int fd, ret;
+  FILE *fp;
+  fd = open_tmp_fd (O_RDONLY);
+
+  /* test mode mismatch. */
+  fp = fdopen (fd, "w");
+  if (fp != NULL || errno != EINVAL)
+    {
+      close_tmp_fd (fd);
+      FAIL_EXIT1 ("fdopen (%d, w) should fail with EINVAL: %m", fd);
+    }
+
+  fp = fdopen (fd, "r");
+  if (fp == NULL)
+    {
+      close_tmp_fd (fd);
+      FAIL_EXIT1 ("fdopen (%d, w): %m", fd);
+    }
+
+  const void *buf = "BBBB";
+  /* fwrite should fail in "r" mode.  */
+  ret = fwrite (buf, 1, 4, fp);
+  if (ret != 0 || ferror (fp) == 0)
+    {
+      close_tmp_fp (fp);
+      FAIL_EXIT1 ("fwrite should fail in \"r\" mode");
+    }
+
+  unsigned char buf2[4];
+  ret = fread (buf2, 1, 4, fp);
+  if (ret != 4)
+    {
+      close_tmp_fp (fp);
+      FAIL_EXIT1 ("fread (): %m");
+    }
+
+  fclose (fp);
+}
+
+/* test "a" fdopen mode.  */
+void
+do_test_fdopen_a (void)
+{
+  int fd, ret;
+  FILE *fp;
+  fd = open_tmp_fd (O_WRONLY | O_CREAT | O_APPEND);
+
+  /* test mode mismatch.  */
+  fp = fdopen (fd, "r+");
+  if (fp != NULL || errno != EINVAL)
+    {
+      close_tmp_fd (fd);
+      FAIL_EXIT1 ("fdopen (%d, \"r+\") should fail with EINVAL: %m", fd);
+    }
+
+  fp = fdopen (fd, "a");
+  if (fp == NULL)
+    {
+      close_tmp_fd (fd);
+      FAIL_EXIT1 ("fdopen (%d, w): %m", fd);
+    }
+
+  const void *buf = "CCCC";
+  ret = fwrite (buf, 1, 4, fp);
+  if (ret != 4)
+    {
+      close_tmp_fp (fp);
+      FAIL_EXIT1 ("fwrite (): %m");
+    }
+
+  /* fread should fail in "a" mode.  */
+  unsigned char buf2[4];
+  clearerr (fp);
+  ret = fread (buf2, 1, 4, fp);
+  if (ret != 0 || ferror (fp) == 0)
+    {
+      close_tmp_fp (fp);
+      FAIL_EXIT1 ("fread should fail \"a\" mode");
+    }
+
+  fclose (fp);
+}
+
+void
+do_test_fdopen_mode (int mode, const char *fmode)
+{
+  int fd, ret;
+  FILE *fp;
+  fd = open_tmp_fd (mode);
+
+  fp = fdopen (fd, fmode);
+  if (fp == NULL)
+    {
+      close_tmp_fd (fd);
+      FAIL_EXIT1 ("fdopen (%d, %s): %m", fd, fmode);
+    }
+
+  const void *buf = "EEEE";
+  ret = fwrite (buf, 1, 4, fp);
+  if (ret != 4)
+    {
+      close_tmp_fp (fp);
+      FAIL_EXIT1 ("fwrite () in mode:%s returns %d: %m", fmode, ret);
+    }
+
+  rewind (fp);
+  unsigned char buf2[4];
+  ret = fread (buf2, 1, 4, fp);
+  if (ret != 4)
+    {
+      close_tmp_fp (fp);
+      FAIL_EXIT1 ("fread () in mode:%s returns %d: %m", fmode, ret);
+    }
+
+  fclose (fp);
+}
+
+static int
+do_test (void)
+{
+
+  prepare_tmp_dir ();
+
+  do_test_fdopen_w ();
+  do_test_fdopen_r ();
+  do_test_fdopen_a ();
+
+  /* test r+ w+ a+ fdopen modes.  */
+  do_test_fdopen_mode (O_RDWR, "r+");
+  do_test_fdopen_mode (O_RDWR | O_CREAT | O_TRUNC, "w+");
+  do_test_fdopen_mode (O_RDWR | O_CREAT | O_APPEND, "a+");
+  xunlink (path_to_file);
+  return 0;
+}
+
+#include <support/test-driver.c>