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/* Test for reading directories with getdents64.
Copyright (C) 2019-2024 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 <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <support/check.h>
#include <support/support.h>
#include <support/xunistd.h>
#include <sys/mman.h>
#include <unistd.h>
/* Called by large_buffer_checks below. */
static void
large_buffer_check (int fd, char *large_buffer, size_t large_buffer_size)
{
xlseek (fd, 0, SEEK_SET);
ssize_t ret = getdents64 (fd, large_buffer, large_buffer_size);
if (ret < 0)
FAIL_EXIT1 ("getdents64 for buffer of %zu bytes failed: %m",
large_buffer_size);
if (ret < offsetof (struct dirent64, d_name))
FAIL_EXIT1 ("getdents64 for buffer of %zu returned small value %zd",
large_buffer_size, ret);
}
/* Bug 24740: Make sure that the system call argument is adjusted
properly for the int type. A large value should stay a large
value, and not wrap around to something small, causing the system
call to fail with EINVAL. */
static void
large_buffer_checks (int fd)
{
size_t large_buffer_size;
if (!__builtin_add_overflow (UINT_MAX, 2, &large_buffer_size))
{
int flags = MAP_ANONYMOUS | MAP_PRIVATE;
#ifdef MAP_NORESERVE
flags |= MAP_NORESERVE;
#endif
void *large_buffer = mmap (NULL, large_buffer_size,
PROT_READ | PROT_WRITE, flags, -1, 0);
if (large_buffer == MAP_FAILED)
printf ("warning: could not allocate %zu bytes of memory,"
" subtests skipped\n", large_buffer_size);
else
{
large_buffer_check (fd, large_buffer, INT_MAX);
large_buffer_check (fd, large_buffer, (size_t) INT_MAX + 1);
large_buffer_check (fd, large_buffer, (size_t) INT_MAX + 2);
large_buffer_check (fd, large_buffer, UINT_MAX);
large_buffer_check (fd, large_buffer, (size_t) UINT_MAX + 1);
large_buffer_check (fd, large_buffer, (size_t) UINT_MAX + 2);
xmunmap (large_buffer, large_buffer_size);
}
}
}
static void
do_test_large_size (void)
{
int fd = xopen (".", O_RDONLY | O_DIRECTORY, 0);
TEST_VERIFY (fd >= 0);
large_buffer_checks (fd);
xclose (fd);
}
static void
do_test_by_size (size_t buffer_size)
{
/* The test compares the iteration order with readdir64. */
DIR *reference = opendir (".");
TEST_VERIFY_EXIT (reference != NULL);
int fd = xopen (".", O_RDONLY | O_DIRECTORY, 0);
TEST_VERIFY (fd >= 0);
/* Perform two passes, with a rewind operating between passes. */
for (int pass = 0; pass < 2; ++pass)
{
/* Check that we need to fill the buffer multiple times. */
int read_count = 0;
while (true)
{
/* Simple way to make sure that the memcpy below does not read
non-existing data. */
struct
{
char buffer[buffer_size];
struct dirent64 pad;
} data;
ssize_t ret = getdents64 (fd, &data.buffer, sizeof (data.buffer));
if (ret < 0)
FAIL_EXIT1 ("getdents64: %m");
if (ret == 0)
break;
++read_count;
char *current = data.buffer;
char *end = data.buffer + ret;
while (current != end)
{
struct dirent64 entry;
memcpy (&entry, current, sizeof (entry));
/* Truncate overlong strings. */
entry.d_name[sizeof (entry.d_name) - 1] = '\0';
TEST_VERIFY (strlen (entry.d_name) < sizeof (entry.d_name) - 1);
errno = 0;
struct dirent64 *refentry = readdir64 (reference);
if (refentry == NULL && errno == 0)
FAIL_EXIT1 ("readdir64 failed too early, at: %s",
entry.d_name);
else if (refentry == NULL)
FAIL_EXIT1 ("readdir64: %m");
TEST_COMPARE_STRING (entry.d_name, refentry->d_name);
TEST_COMPARE (entry.d_ino, refentry->d_ino);
TEST_COMPARE (entry.d_off, refentry->d_off);
TEST_COMPARE (entry.d_type, refentry->d_type);
/* Offset zero is reserved for the first entry. */
TEST_VERIFY (entry.d_off != 0);
TEST_VERIFY_EXIT (entry.d_reclen <= end - current);
current += entry.d_reclen;
}
}
/* We expect to have reached the end of the stream. */
errno = 0;
TEST_VERIFY (readdir64 (reference) == NULL);
TEST_COMPARE (errno, 0);
/* direntries_read has been called more than once. */
TEST_VERIFY (read_count > 0);
/* Rewind both directory streams. */
xlseek (fd, 0, SEEK_SET);
rewinddir (reference);
}
xclose (fd);
closedir (reference);
}
static int
do_test (void)
{
do_test_by_size (512);
do_test_by_size (1024);
do_test_by_size (4096);
do_test_large_size ();
return 0;
}
#include <support/test-driver.c>
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