Add new tests for fopen

Adding some basic tests for fopen, testing different modes, stream
positioning and concurrent read/write operation on files.
Reviewed-by: DJ Delorie <dj@redhat.com>
This commit is contained in:
Martin Coufal 2025-01-23 13:04:06 +01:00 committed by DJ Delorie
parent 42aba91895
commit 45c42b65c2
4 changed files with 531 additions and 0 deletions

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@ -244,6 +244,7 @@ tests := \
tst-fmemopen2 \
tst-fmemopen3 \
tst-fmemopen4 \
tst-fopen \
tst-fphex \
tst-fphex-wide \
tst-fread \

279
stdio-common/tst-fopen.c Normal file
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@ -0,0 +1,279 @@
/* Basic test for fopen.
Copyright (C) 2025 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 <stdio.h>
#include <string.h>
#include <unistd.h>
#include <support/check.h>
#include <support/temp_file.h>
#include <support/xstdio.h>
#define APPENDED_TEXT "This is appended text. "
#define DEFAULT_TEXT "Lorem ipsum dolor sit amet, consectetur " \
"adipiscing elit, sed do eiusmod tempor incididunt ut labore et " \
"dolore magna aliqua."
#define MAX_BUFFER_SIZE 300
static int
do_test (void)
{
char *temp_file;
FILE *fd_file = NULL;
char read_buffer[MAX_BUFFER_SIZE] = "";
size_t ret;
/* Prepare files. */
int fd = create_temp_file ("tst-fopen.", &temp_file);
TEST_VERIFY_EXIT (fd != -1);
fd_file = fdopen (fd, "w");
ret = fwrite (DEFAULT_TEXT, sizeof (char), strlen (DEFAULT_TEXT), fd_file);
TEST_COMPARE (ret, strlen (DEFAULT_TEXT));
xfclose (fd_file);
/* Test 1: This checks for fopen with mode "r". Open text file for
reading. The stream is positioned at the beginning of the file. */
printf ("Test 1: This checks for fopen with mode \"r\".\n");
fd_file = fopen (temp_file, "r");
TEST_COMPARE (ferror (fd_file), 0);
TEST_VERIFY (fd_file != NULL);
TEST_COMPARE (ftell (fd_file), 0);
/* Read should succeed. */
ret = fread (read_buffer, sizeof (char), MAX_BUFFER_SIZE, fd_file);
TEST_COMPARE (ferror (fd_file), 0);
TEST_COMPARE (ret, strlen (DEFAULT_TEXT));
TEST_VERIFY (strcmp (read_buffer, DEFAULT_TEXT) == 0);
/* Write should fail. */
errno = 0;
ret = fwrite (DEFAULT_TEXT, sizeof (char), strlen (DEFAULT_TEXT), fd_file);
TEST_VERIFY (ferror (fd_file) != 0);
TEST_COMPARE (errno, EBADF);
TEST_COMPARE (ret, 0);
clearerr (fd_file);
/* Opening non-existent file should fail. */
xfclose (fd_file);
errno = 0;
fd_file = fopen ("file-that-does-not-exist", "r");
TEST_VERIFY (fd_file == NULL);
TEST_COMPARE (errno, ENOENT);
TEST_VERIFY (fd_file == NULL);
memset (read_buffer, 0, MAX_BUFFER_SIZE);
/* Test 2: This checks for fopen with mode "r+". Open for reading and
writing. The stream is positioned at the beginning of the file. */
printf ("Test 2: This checks for fopen with mode \"r+\".\n");
fd_file = fopen (temp_file, "r+");
TEST_COMPARE (ferror (fd_file), 0);
TEST_VERIFY (fd_file != NULL);
TEST_COMPARE (ftell (fd_file), 0);
/* Read should succeed. */
ret = fread (read_buffer, sizeof (char), MAX_BUFFER_SIZE, fd_file);
TEST_COMPARE (ferror (fd_file), 0);
TEST_COMPARE (ret, strlen (DEFAULT_TEXT));
TEST_VERIFY (strcmp (read_buffer, DEFAULT_TEXT) == 0);
fflush (fd_file);
/* File position indicator expected at 0 + read bytes. */
TEST_COMPARE (ftell (fd_file), ret);
/* Write should succeed. */
ret = fwrite (DEFAULT_TEXT, sizeof (char), strlen (DEFAULT_TEXT), fd_file);
TEST_COMPARE (ferror (fd_file), 0);
TEST_COMPARE (ret, strlen (DEFAULT_TEXT));
/* Opening non-existent file should fail. */
xfclose (fd_file);
errno = 0;
fd_file = fopen ("file-that-does-not-exist", "r+");
TEST_VERIFY (fd_file == NULL);
TEST_COMPARE (errno, ENOENT);
TEST_VERIFY (fd_file == NULL);
memset (read_buffer, 0, MAX_BUFFER_SIZE);
/* Test 3: This checks for fopen with mode "w". Truncate file to zero
length or create text file for writing. The stream is positioned
at the beginning of the file. */
printf ("Test 3: This checks for fopen with mode \"w\".\n");
fd_file = fopen (temp_file, "w");
TEST_COMPARE (ferror (fd_file), 0);
TEST_VERIFY (fd_file != NULL);
TEST_COMPARE (ftell (fd_file), 0);
/* Read should fail. */
errno = 0;
ret = fread (read_buffer, sizeof (char), MAX_BUFFER_SIZE, fd_file);
TEST_VERIFY (ferror (fd_file) != 0);
TEST_COMPARE (errno, EBADF);
TEST_COMPARE (ret, 0);
clearerr (fd_file);
/* Write should succeed. */
ret = fwrite (DEFAULT_TEXT, sizeof (char), strlen (DEFAULT_TEXT), fd_file);
TEST_COMPARE (ferror (fd_file), 0);
TEST_COMPARE (ret, strlen (DEFAULT_TEXT));
/* Opening non-existent file should succeed. */
xfclose (fd_file);
fd_file = fopen ("/tmp/file-that-does-not-exist", "w");
TEST_COMPARE (ferror (fd_file), 0);
TEST_VERIFY (fd_file != NULL);
TEST_COMPARE (ftell (fd_file), 0);
xfclose (fd_file);
remove ("/tmp/file-that-does-not-exist");
memset (read_buffer, 0, MAX_BUFFER_SIZE);
/* Test 4: This checks for fopen with mode "w+". Open for reading and
writing. The file is created if it does not exist, otherwise it is
truncated. The stream is positioned at the beginning of the file.
*/
printf ("Test 4: This checks for fopen with mode \"w+\".\n");
fd_file = fopen (temp_file, "w+");
TEST_COMPARE (ferror (fd_file), 0);
TEST_VERIFY (fd_file != NULL);
TEST_COMPARE (ftell (fd_file), 0);
/* Read should succeed. */
ret = fread (read_buffer, sizeof (char), MAX_BUFFER_SIZE, fd_file);
TEST_COMPARE (ferror (fd_file), 0);
TEST_COMPARE (ret, 0);
TEST_VERIFY (read_buffer[0] == '\0');
/* Write should succeed. */
ret = fwrite (DEFAULT_TEXT, sizeof (char), strlen (DEFAULT_TEXT), fd_file);
TEST_COMPARE (ferror (fd_file), 0);
TEST_COMPARE (ret, strlen (DEFAULT_TEXT));
/* Opening non-existent file should succeed. */
xfclose (fd_file);
fd_file = fopen ("/tmp/file-that-does-not-exist", "w+");
TEST_COMPARE (ferror (fd_file), 0);
TEST_VERIFY (fd_file != NULL);
TEST_COMPARE (ftell (fd_file), 0);
xfclose (fd_file);
remove ("/tmp/file-that-does-not-exist");
memset (read_buffer, 0, MAX_BUFFER_SIZE);
/* Test 5: This checks for fopen with mode "a". Open for appending
(writing at end of file). The file is created if it does not
exist. The stream is positioned at the end of the file. */
printf ("Test 5: This checks for fopen with mode \"a\".\n");
fd_file = fopen (temp_file, "a");
TEST_COMPARE (ferror (fd_file), 0);
TEST_VERIFY (fd_file != NULL);
TEST_COMPARE (ftell (fd_file), strlen (DEFAULT_TEXT));
/* Read should fail. */
errno = 0;
ret = fread (read_buffer, sizeof (char), MAX_BUFFER_SIZE, fd_file);
TEST_VERIFY (ferror (fd_file) != 0);
TEST_COMPARE (errno, EBADF);
TEST_COMPARE (ret, 0);
clearerr (fd_file);
/* Write should succeed. */
ret = fwrite (APPENDED_TEXT, sizeof (char), strlen (APPENDED_TEXT), fd_file);
TEST_COMPARE (ferror (fd_file), 0);
TEST_COMPARE (ret, strlen (APPENDED_TEXT));
/* The file position indicator for the stream is advanced by the
* number of bytes successfully read or written. */
TEST_COMPARE (ftell (fd_file), strlen (DEFAULT_TEXT) + ret);
/* Opening non-existent file should succeed. */
xfclose (fd_file);
fd_file = fopen ("/tmp/file-that-does-not-exist", "a");
TEST_COMPARE (ferror (fd_file), 0);
TEST_VERIFY (fd_file != NULL);
TEST_COMPARE (ftell (fd_file), 0);
xfclose (fd_file);
remove ("/tmp/file-that-does-not-exist");
memset (read_buffer, 0, MAX_BUFFER_SIZE);
/* Test 6: This checks for fopen with mode "a+". Open for reading and
appending (writing at end of file). The file is created if it does
not exist. Output is always appended to the end of the file. The
initial file position for reading is at the beginning of the file,
but it is advanced to the end prior to each write. */
printf ("Test 6: This checks for fopen with mode \"a+\".\n");
errno = 0;
fd_file = fopen (temp_file, "a+");
TEST_COMPARE (errno, 0);
TEST_VERIFY (fd_file != NULL);
TEST_COMPARE (ftell (fd_file), 0);
/* Read should succeed. */
ret = fread (read_buffer, sizeof (char), MAX_BUFFER_SIZE, fd_file);
TEST_COMPARE (ferror (fd_file), 0);
TEST_COMPARE (ret, strlen (DEFAULT_TEXT) + strlen (APPENDED_TEXT));
TEST_VERIFY (strcmp (read_buffer, DEFAULT_TEXT APPENDED_TEXT) == 0);
/* Write should succeed. */
const char* SECOND_APPEND = "This is second append.";
ret = fwrite (SECOND_APPEND, sizeof (char), strlen (SECOND_APPEND), fd_file);
TEST_COMPARE (ferror (fd_file), 0);
TEST_COMPARE (ret, strlen (SECOND_APPEND));
/* The file position indicator for the stream is advanced by the
number of bytes successfully read or written. */
TEST_COMPARE (ftell (fd_file),
strlen (DEFAULT_TEXT) + strlen (APPENDED_TEXT) + ret);
/* Opening non-existent file should succeed. */
xfclose (fd_file);
fd_file = fopen ("/tmp/file-that-does-not-exist", "a+");
TEST_COMPARE (ferror (fd_file), 0);
TEST_VERIFY (fd_file != NULL);
TEST_COMPARE (ftell (fd_file), 0);
xfclose (fd_file);
remove ("/tmp/file-that-does-not-exist");
memset (read_buffer, 0, MAX_BUFFER_SIZE);
/* Test 7: This checks for fopen with other valid modes set, such as
"rc", "we" or "am". The test calls fopen with these modes and
checks that no errors appear. */
printf ("Test 7: This checks for fopen with other valid modes set, "
"such as \"rc\", \"we\" or \"am\".\n");
/* These modes all operate correctly with the file already present. */
static const char *valid_modes[] =
{ "rc", "we", "am", "r+x", "wb+", "ab", 0 };
const char **p = valid_modes;
while (*p != 0)
{
fd_file = fopen (temp_file, *p);
TEST_COMPARE (ferror (fd_file), 0);
TEST_VERIFY (fd_file != NULL);
xfclose (fd_file);
++p;
}
/* Test 8: This checks for fopen with invalid modes. The test calls
fopen with these modes and checks that opening existing files with
invalid mode fails and that opening non-existing files with invalid
mode doesn't create a new file. */
printf ("Test 8: This checks for fopen with invalid modes.\n");
static const char *invalid_modes[] = { "0", "tr", "z", "x", " ", 0 };
p = invalid_modes;
while (*p != 0)
{
errno = 0;
fd_file = fopen (temp_file, *p);
TEST_VERIFY (fd_file == NULL);
TEST_COMPARE (errno, EINVAL);
errno = 0;
fd_file = fopen ("/tmp/file-that-does-not-exist", *p);
TEST_VERIFY (fd_file == NULL);
TEST_COMPARE (errno, EINVAL);
++p;
TEST_VERIFY (access ("/tmp/file-that-does-not-exist", F_OK) == -1);
}
return 0;
}
#include <support/test-driver.c>

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@ -154,6 +154,7 @@ tests += \
tst-exit3 \
tst-flock1 \
tst-flock2 \
tst-fopen-threaded \
tst-fork1 \
tst-fork2 \
tst-fork3 \

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@ -0,0 +1,250 @@
/* Test for fread and fwrite with multiple threads.
Copyright (C) 2025 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/>. */
/* Description of test intent.
The test creates NUM_THREADS threads for reading and writing to the
prepared file. The prepared file contains 'NUM_THREADS - 1' bytes
where each byte is unique number from 0 to 'NUM_THREADS - 2'. If all
operations are correctly multi-threaded safe then all concurent read
operations should succeed and read a unique 1 byte value. The last
thread to read should get an EOF. In concurrent write, all write
operations should succeed and the file should contain all unique 1
byte values from 0 to 'NUM_THREADS - 1'. Both concurrent read and
concurrent write tests are repeated ITERS times to increase
the probability of detecting concurrency issues. */
#include <errno.h>
#include <pthread.h>
#include <stdbool.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <support/check.h>
#include <support/temp_file.h>
#include <support/xstdio.h>
#include <support/xthread.h>
#define NUM_THREADS 100
#define ITERS 10
char *temp_file;
pthread_barrier_t barrier;
struct thread_data
{
FILE *fd;
/* Read value or value to be written. */
unsigned char value;
bool eof;
};
static void *
threadReadRoutine (void *argv)
{
struct thread_data *my_data;
unsigned char read_buffer;
int ret = 0;
my_data = (struct thread_data *) argv;
/* Wait for all threads to be ready to read. */
xpthread_barrier_wait (&barrier);
ret =
fread (&read_buffer, sizeof (char), sizeof (read_buffer), my_data->fd);
if (feof (my_data->fd) != 0)
{
clearerr (my_data->fd);
my_data->eof = true;
}
else
{
TEST_COMPARE (ret, 1);
/* Save the read value. */
my_data->value = read_buffer;
}
TEST_COMPARE (ferror (my_data->fd), 0);
return NULL;
}
void *
threadWriteRoutine (void *argv)
{
struct thread_data *my_data;
int ret = 0;
my_data = (struct thread_data *) argv;
/* Wait for all threads to be ready to write. */
xpthread_barrier_wait (&barrier);
ret = fwrite (&my_data->value, sizeof (unsigned char), 1, my_data->fd);
TEST_COMPARE (ferror (my_data->fd), 0);
TEST_COMPARE (feof (my_data->fd), 0);
TEST_COMPARE (ret, 1);
return NULL;
}
void *
threadOpenCloseRoutine (void *argv)
{
/* Wait for all threads to be ready to call fopen and fclose. */
xpthread_barrier_wait (&barrier);
FILE *fd = xfopen ("/tmp/openclosetest", "w+");
xfclose (fd);
return NULL;
}
static int
do_test (void)
{
FILE *fd_file = NULL;
unsigned char buffer[NUM_THREADS] = "0";
size_t ret = 0;
pthread_t threads[NUM_THREADS];
struct thread_data thread_data_array[NUM_THREADS];
bool present_values[NUM_THREADS] = { false };
/* Prepare files. */
for (int i = 0; i < NUM_THREADS; i++)
buffer[i] = i;
int fd = create_temp_file ("tst-fopen.", &temp_file);
TEST_VERIFY_EXIT (fd != -1);
fd_file = fdopen (fd, "w");
/* NUM_THREADS - 1: last thread will read EOF */
ret = fwrite (buffer, sizeof (unsigned char), NUM_THREADS - 1, fd_file);
TEST_COMPARE (ret, NUM_THREADS - 1);
xfclose (fd_file);
/* Test 1: Concurrent read. */
for (int reps = 1; reps <= ITERS; reps++)
{
fd_file = xfopen (temp_file, "r");
xpthread_barrier_init (&barrier, NULL, NUM_THREADS);
for (int i = 0; i < NUM_THREADS; i++)
{
thread_data_array[i].fd = fd_file;
/* Initialize with highest possible value so it's easier to debug if
anything goes wrong. */
thread_data_array[i].value = 255;
thread_data_array[i].eof = false;
threads[i] =
xpthread_create (support_small_stack_thread_attribute (),
threadReadRoutine,
(void *) &thread_data_array[i]);
}
for (int i = 0; i < NUM_THREADS; i++)
{
xpthread_join (threads[i]);
}
xpthread_barrier_destroy (&barrier);
xfclose (fd_file);
/* Verify read values. */
int eof_cnt = 0;
for (int i = 0; i < NUM_THREADS; i++)
present_values[i] = false;
for (int i = 0; i < NUM_THREADS; i++)
{
if (thread_data_array[i].eof)
{
/* EOF was read. */
present_values[NUM_THREADS - 1] = true;
eof_cnt++;
}
else
{
/* The same value shouldn't be read twice. */
TEST_VERIFY (!present_values[thread_data_array[i].value]);
present_values[thread_data_array[i].value] = true;
}
}
/* EOF is read exactly once. */
TEST_COMPARE (eof_cnt, 1);
for (int i = 0; i < NUM_THREADS; i++)
{
/* All values should be read. */
TEST_VERIFY (present_values[i]);
}
}
/* Test 2: Concurrent write. */
for (int reps = 1; reps <= ITERS; reps++)
{
fd_file = xfopen (temp_file, "w");
xpthread_barrier_init (&barrier, NULL, NUM_THREADS);
for (int i = 0; i < NUM_THREADS; i++)
{
thread_data_array[i].fd = fd_file;
thread_data_array[i].value = i;
threads[i] =
xpthread_create (support_small_stack_thread_attribute (),
threadWriteRoutine,
(void *) &thread_data_array[i]);
}
for (int i = 0; i < NUM_THREADS; i++)
{
xpthread_join (threads[i]);
}
xpthread_barrier_destroy (&barrier);
xfclose (fd_file);
/* Verify written values. */
for (int i = 0; i < NUM_THREADS; i++)
present_values[i] = false;
memset (buffer, 0, NUM_THREADS);
fd_file = xfopen (temp_file, "r");
ret = fread (buffer, sizeof (unsigned char), NUM_THREADS, fd_file);
TEST_COMPARE (ret, NUM_THREADS);
for (int i = 0; i < NUM_THREADS; i++)
{
/* The same value shouldn't be written twice. */
TEST_VERIFY (!present_values[buffer[i]]);
present_values[buffer[i]] = true;
}
for (int i = 0; i < NUM_THREADS; i++)
{
/* All values should be written. */
TEST_VERIFY (present_values[i]);
}
xfclose (fd_file);
}
/* Test 3: Concurrent open/close. */
for (int reps = 1; reps <= ITERS; reps++)
{
xpthread_barrier_init (&barrier, NULL, NUM_THREADS);
for (int i = 0; i < NUM_THREADS; i++)
{
threads[i] =
xpthread_create (support_small_stack_thread_attribute (),
threadOpenCloseRoutine, NULL);
}
for (int i = 0; i < NUM_THREADS; i++)
{
xpthread_join (threads[i]);
}
xpthread_barrier_destroy (&barrier);
}
return 0;
}
#include <support/test-driver.c>