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Add new tests for fopen

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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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1
sysdeps/pthread/Makefile
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@ -154,6 +154,7 @@ tests += \
tst-exit3 \
tst-flock1 \
tst-flock2 \
tst-fopen-threaded \
tst-fork1 \
tst-fork2 \
tst-fork3 \

250
sysdeps/pthread/tst-fopen-threaded.c Normal file
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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>