Add a new fwrite test for memory streams

Ensure that fwrite() behaves correctly when using memory streams.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
This commit is contained in:
Tulio Magno Quites Machado Filho 2024-08-29 14:12:41 -03:00
parent 5d4ab106d4
commit dccc9a5161
2 changed files with 178 additions and 0 deletions

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@ -223,6 +223,7 @@ tests := \
tst-freopen64-3 \
tst-fseek \
tst-fwrite \
tst-fwrite-memstrm \
tst-fwrite-ro \
tst-getline \
tst-getline-enomem \

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@ -0,0 +1,177 @@
/* Test fwrite on a memory stream.
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/temp_file.h>
#include <support/xstdio.h>
#include <support/xunistd.h>
void
test_ro (void)
{
FILE *f;
char *out;
/* Try to allocate a small buffer for this test. */
out = malloc (2);
TEST_VERIFY_EXIT (out != NULL);
/* Try to open the allocated buffer as a read-only stream. */
f = fmemopen (out, 2, "r");
TEST_VERIFY_EXIT (f != NULL);
/* Try to write to the temporary file with nmemb = 0, then check that
fwrite returns 0. No errors are expected from this. */
TEST_COMPARE (fwrite ("a", 1, 0, f), 0);
TEST_COMPARE (ferror (f), 0);
/* Try to write to the temporary file with size = 0, then check that
fwrite returns 0. No errors are expected from this. */
TEST_COMPARE (fwrite ("a", 0, 1, f), 0);
TEST_COMPARE (ferror (f), 0);
/* Try to write a single byte to the temporary file, then check that
fwrite returns 0. Check if an error was reported. */
TEST_COMPARE (fwrite ("a", 1, 1, f), 0);
TEST_COMPARE (ferror (f), 1);
clearerr (f);
xfclose (f);
free (out);
}
/* Length of the output buffer in bytes. */
#define RWBUF_SIZE 16 * 1024
/* Maximum number of bytes to be written in output buffer. The rest will be
used to check against overflow. */
#define RWBUF_SIZE_WRITABLE RWBUF_SIZE-2048
/* Use the following byte to identify areas that should have not been
modified. */
#define KNOWN_BYTE 0xaa
void
test_one_rw (const char *in, size_t size, size_t nmemb,
size_t expected_ret)
{
FILE *f;
char *out, *expected_out;
/* Total number of bytes expected to be written. */
size_t expected_bytes = size * nmemb;
printf ("Testing with size = %zd, nmemb = %zd\n", size, nmemb);
TEST_VERIFY_EXIT (expected_ret <= RWBUF_SIZE_WRITABLE);
TEST_VERIFY_EXIT (expected_bytes <= RWBUF_SIZE_WRITABLE);
/* Try to allocate a buffer for this test and initialize it with
known contents. */
out = malloc (RWBUF_SIZE);
TEST_VERIFY_EXIT (out != NULL);
memset (out, KNOWN_BYTE, RWBUF_SIZE);
/* Try to allocate a buffer and fill it with the contents that are expected
to be in memory after flushing/closing the memory stream. */
expected_out = malloc (RWBUF_SIZE);
TEST_VERIFY_EXIT (expected_out != NULL);
if (expected_bytes > 0)
{
memcpy (expected_out, in, expected_bytes);
expected_out[expected_bytes] = 0;
memset (expected_out + expected_bytes + 1, KNOWN_BYTE,
RWBUF_SIZE - expected_bytes - 1);
}
else
{
/* No changes to the output are expected. */
memset (expected_out, KNOWN_BYTE, RWBUF_SIZE);
}
/* Try to open the allocated buffer as a read-write stream. */
f = fmemopen (out, RWBUF_SIZE, "w");
TEST_VERIFY_EXIT (f != NULL);
/* Try to write to the memory stream. Check if fwrite() returns the
expected value. No errors are expected. */
TEST_COMPARE (fwrite (in, size, nmemb, f), expected_ret);
TEST_COMPARE (ferror (f), 0);
xfclose (f);
/* Ensure the output has the expected contents. */
TEST_COMPARE (memcmp (out, expected_out, expected_bytes), 0);
free (expected_out);
free (out);
}
void
test_rw (void)
{
char * in;
int i, j;
size_t size[] = {1, 8, 11, 16, 17, 0};
size_t nmemb[] = {32, 83, 278, 709, 4097, RWBUF_SIZE / 2,
RWBUF_SIZE_WRITABLE, 0};
size_t n;
/* Try to write to the temporary file with nmemb = 0, then check that
fwrite returns 0; */
test_one_rw ("a", 1, 0, 0);
/* Try to write to the temporary file with size = 0, then check that
fwrite returns 0; */
test_one_rw ("a", 0, 1, 0);
/* Try to write a single byte to the temporary file, then check that
fwrite returns 1; */
test_one_rw ("a", 1, 2, 2);
in = malloc (RWBUF_SIZE);
TEST_VERIFY_EXIT (in != NULL);
for (i = 0; i < RWBUF_SIZE / 2; i++)
in[i] = i % 0xff;
/* Test with all posibilities of size[] x nmemb[]. */
for (i = 0; nmemb[i] != 0; i++)
{
for (j = 0; size[j] != 0; j++)
{
n = nmemb[i] / size[j];
test_one_rw (in, size[j], n, n);
}
/* Run the test with a single item of maximum size. */
test_one_rw (in, nmemb[i], 1, 1);
}
free (in);
}
static int
do_test (void)
{
test_ro ();
test_rw ();
return 0;
}
#include <support/test-driver.c>