Add tests of fread

There seem to be no glibc tests specifically for the fread function.
Add basic tests of that function.

Tested for x86_64.

(cherry picked from commit d14c977c65aac7db35bb59380ef99d6582c4f930)

2 files changed, 135 insertions, 0 deletions

diff --git a/stdio-common/Makefile b/stdio-common/Makefile
index 5af53d61fd..3396090be1 100644
--- a/stdio-common/Makefile
+++ b/stdio-common/Makefile
@@ -217,6 +217,7 @@ tests := \
   tst-fmemopen4 \
   tst-fphex \
   tst-fphex-wide \
+  tst-fread \
   tst-fseek \
   tst-fwrite \
   tst-gets \
diff --git a/stdio-common/tst-fread.c b/stdio-common/tst-fread.c
new file mode 100644
index 0000000000..4d9a7895f6
--- /dev/null
+++ b/stdio-common/tst-fread.c
@@ -0,0 +1,134 @@
+/* Test fread.
+   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 <stdlib.h>
+#include <string.h>
+
+#include <support/check.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)
+{
+  char *temp_dir = support_create_temp_directory ("tst-fread");
+  char *file1 = xasprintf ("%s/file1", temp_dir);
+  support_write_file_string (file1, "file1");
+  add_temp_file (file1);
+  FILE *fp;
+  size_t ret;
+  char buf[1024];
+
+  verbose_printf ("test single-byte reads\n");
+  fp = xfopen (file1, "r");
+  memset (buf, 0, sizeof buf);
+  ret = fread (buf, 1, 2, fp);
+  TEST_COMPARE (ret, 2);
+  TEST_COMPARE (buf[0], 'f');
+  TEST_COMPARE (buf[1], 'i');
+  TEST_COMPARE (feof (fp), 0);
+  TEST_COMPARE (ftell (fp), 2);
+  memset (buf, 0, sizeof buf);
+  ret = fread (buf, 1, 3, fp);
+  TEST_COMPARE (ret, 3);
+  TEST_COMPARE (buf[0], 'l');
+  TEST_COMPARE (buf[1], 'e');
+  TEST_COMPARE (buf[2], '1');
+  TEST_COMPARE (ftell (fp), 5);
+  TEST_COMPARE (feof (fp), 0);
+  memset (buf, 0, sizeof buf);
+  ret = fread (buf, 1, 1, fp);
+  TEST_COMPARE (ret, 0);
+  TEST_COMPARE (!!feof (fp), 1);
+  TEST_COMPARE (ferror (fp), 0);
+  TEST_COMPARE (ftell (fp), 5);
+  xfclose (fp);
+
+  verbose_printf ("test single-byte reads, EOF part way through\n");
+  fp = xfopen (file1, "r");
+  memset (buf, 0, sizeof buf);
+  ret = fread (buf, 1, sizeof buf, fp);
+  TEST_COMPARE (ret, 5);
+  TEST_COMPARE (buf[0], 'f');
+  TEST_COMPARE (buf[1], 'i');
+  TEST_COMPARE (buf[2], 'l');
+  TEST_COMPARE (buf[3], 'e');
+  TEST_COMPARE (buf[4], '1');
+  TEST_COMPARE (!!feof (fp), 1);
+  TEST_COMPARE (ferror (fp), 0);
+  TEST_COMPARE (ftell (fp), 5);
+  xfclose (fp);
+
+  verbose_printf ("test multi-byte reads\n");
+  fp = xfopen (file1, "r");
+  memset (buf, 0, sizeof buf);
+  ret = fread (buf, 2, 2, fp);
+  TEST_COMPARE (ret, 2);
+  TEST_COMPARE (buf[0], 'f');
+  TEST_COMPARE (buf[1], 'i');
+  TEST_COMPARE (buf[2], 'l');
+  TEST_COMPARE (buf[3], 'e');
+  TEST_COMPARE (feof (fp), 0);
+  TEST_COMPARE (ftell (fp), 4);
+  memset (buf, 0, sizeof buf);
+  ret = fread (buf, 3, 3, fp);
+  TEST_COMPARE (ret, 0);
+  /* The bytes written for a partial element read are unspecified.  */
+  TEST_COMPARE (!!feof (fp), 1);
+  TEST_COMPARE (ferror (fp), 0);
+  TEST_COMPARE (ftell (fp), 5);
+  xfclose (fp);
+
+  verbose_printf ("test read error\n");
+  fp = xfopen (file1, "r");
+  xclose (fileno (fp));
+  memset (buf, 0, sizeof buf);
+  ret = fread (buf, 1, sizeof buf, fp);
+  TEST_COMPARE (ret, 0);
+  TEST_COMPARE (feof (fp), 0);
+  TEST_COMPARE (!!ferror (fp), 1);
+  fclose (fp);
+
+  verbose_printf ("test zero size\n");
+  fp = xfopen (file1, "r");
+  ret = fread (buf, 0, SIZE_MAX, fp);
+  TEST_COMPARE (ret, 0);
+  TEST_COMPARE (feof (fp), 0);
+  TEST_COMPARE (ferror (fp), 0);
+  TEST_COMPARE (ftell (fp), 0);
+  xfclose (fp);
+
+  verbose_printf ("test zero items\n");
+  fp = xfopen (file1, "r");
+  ret = fread (buf, SIZE_MAX, 0, fp);
+  TEST_COMPARE (ret, 0);
+  TEST_COMPARE (feof (fp), 0);
+  TEST_COMPARE (ferror (fp), 0);
+  TEST_COMPARE (ftell (fp), 0);
+  xfclose (fp);
+
+  free (temp_dir);
+  free (file1);
+  return 0;
+}
+
+#include <support/test-driver.c>