glibc/stdio-common/tst-fgets2.c
DJ Delorie 4945ffc88a fgets: more tests
Add more tests for unusual situations fgets() might see:

* zero size file
* zero sized buffer
* NULL buffer
* NUL data
* writable stream
* closed stream

Reviewed-by: Florian Weimer <fweimer@redhat.com>
2024-09-04 16:24:12 -04:00

254 lines
6.3 KiB
C

/* Test for additional fgets error handling.
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 <libc-diag.h>
#include <stdio.h>
#include <error.h>
#include <errno.h>
#include <limits.h>
#include <mcheck.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/types.h>
#include <support/support.h>
#include <support/check.h>
/* This avoids compiler warnings about passing NULL where a valid
pointer is expected. */
static void *volatile null = NULL;
/* Implementation of our FILE stream backend. */
static int bytes_read;
static int cookie_valid = 0;
struct Cookie {
const char *buffer;
int bufptr;
int bufsz;
};
#define VALIDATE_COOKIE() if (! cookie_valid) { \
FAIL ("call to %s after file closed", __FUNCTION__); \
return -1; \
}
static ssize_t
io_read (void *vcookie, char *buf, size_t size)
{
struct Cookie *cookie = (struct Cookie *) vcookie;
VALIDATE_COOKIE ();
if (size > cookie->bufsz - cookie->bufptr)
size = cookie->bufsz - cookie->bufptr;
memcpy (buf, cookie->buffer + cookie->bufptr, size);
cookie->bufptr += size;
bytes_read += size;
return size;
}
static ssize_t
io_write (void *vcookie, const char *buf, size_t size)
{
VALIDATE_COOKIE ();
FAIL_EXIT1 ("io_write called");
}
static int
io_seek (void *vcookie, off64_t *position, int whence)
{
VALIDATE_COOKIE ();
FAIL_EXIT1 ("io_seek called");
}
static int
io_clean (void *vcookie)
{
struct Cookie *cookie = (struct Cookie *) vcookie;
VALIDATE_COOKIE ();
cookie->buffer = NULL;
cookie->bufsz = 0;
cookie->bufptr = 0;
cookie_valid = 0;
free (cookie);
return 0;
}
cookie_io_functions_t io_funcs = {
.read = io_read,
.write = io_write,
.seek = io_seek,
.close = io_clean
};
FILE *
io_open (const char *buffer, int buflen, const char *mode, void **vcookie)
{
FILE *f;
struct Cookie *cookie;
cookie = (struct Cookie *) xcalloc (1, sizeof (struct Cookie));
*vcookie = cookie;
cookie_valid = 1;
cookie->buffer = buffer;
cookie->bufsz = buflen;
bytes_read = 0;
f = fopencookie (cookie, mode, io_funcs);
if (f == NULL)
FAIL_EXIT1 ("fopencookie failed");
clearerr (f);
return f;
}
/* The test cases. */
#define my_open(s,l,m) io_open (s, l, m, (void *) &cookie)
#define TEST_COMPARE_0x11(buf, len) \
TEST_COMPARE_BLOB (buf + (len), sizeof (buf) - (len), \
buf2, sizeof (buf) - (len));
#define check_flags(f, expected_eof, expected_err) \
{ \
if (expected_eof) \
TEST_VERIFY (feof (f) != 0); \
else \
TEST_VERIFY (feof (f) == 0); \
if (expected_err) \
TEST_VERIFY (ferror (f) != 0); \
else \
TEST_VERIFY (ferror (f) == 0); \
}
static int
do_test (void)
{
FILE *f;
struct Cookie *cookie;
char buf [10];
char buf2 [10];
char *returned_string;
memset (buf2, 0x11, sizeof (buf2));
printf ("testing base operation...\n");
f = my_open ("hello\n", 6, "r");
memset (buf, 0x11, sizeof (buf));
returned_string = fgets (buf, sizeof (buf) - 1, f);
TEST_VERIFY (returned_string == buf);
TEST_COMPARE_BLOB (buf, bytes_read + 1, "hello\n\0", 7);
TEST_COMPARE_0x11 (buf, bytes_read + 1);
check_flags (f, 0, 0);
fclose (f);
printf ("testing zero size file...\n");
f = my_open ("hello\n", 0, "r");
memset (buf, 0x11, sizeof (buf));
returned_string = fgets (buf, sizeof (buf) - 1, f);
TEST_VERIFY (returned_string == NULL);
TEST_VERIFY (bytes_read == 0);
check_flags (f, 1, 0);
fclose (f);
printf ("testing zero size buffer...\n");
f = my_open ("hello\n", 6, "r");
memset (buf, 0x11, sizeof (buf));
returned_string = fgets (buf, 0, f);
TEST_VERIFY (returned_string == NULL);
TEST_VERIFY (bytes_read == 0);
check_flags (f, 0, 0);
fclose (f);
printf ("testing NULL buffer with empty stream...\n");
f = my_open ("hello\n", 0, "r");
memset (buf, 0x11, sizeof (buf));
returned_string = fgets (null, sizeof (buf), f);
TEST_VERIFY (returned_string == NULL);
TEST_VERIFY (bytes_read == 0);
check_flags (f, 1, 0);
fclose (f);
printf ("testing embedded NUL...\n");
f = my_open ("hel\0lo\n", 7, "r");
memset (buf, 0x11, sizeof (buf));
returned_string = fgets (buf, sizeof (buf) - 1, f);
TEST_VERIFY (returned_string == buf);
TEST_COMPARE_BLOB (buf, bytes_read + 1, "hel\0lo\n\0", 8);
TEST_COMPARE_0x11 (buf, bytes_read + 1);
check_flags (f, 0, 0);
fclose (f);
printf ("testing writable stream...\n");
f = my_open ("hel\0lo\n", 7, "w");
memset (buf, 0x11, sizeof (buf));
returned_string = fgets (buf, sizeof (buf) - 1, f);
TEST_VERIFY (returned_string == NULL);
TEST_VERIFY (bytes_read == 0);
check_flags (f, 0, 1);
fclose (f);
printf ("testing closed fd stream...\n");
int fd = open ("/dev/null", O_RDONLY);
f = fdopen (fd, "r");
close (fd);
memset (buf, 0x11, sizeof (buf));
returned_string = fgets (buf, sizeof (buf) - 1, f);
TEST_VERIFY (returned_string == NULL);
TEST_VERIFY (bytes_read == 0);
check_flags (f, 0, 1);
fclose (f);
#ifdef IO_DEBUG
/* These tests only pass if glibc is built with -DIO_DEBUG, but are
included for reference. */
printf ("testing NULL descriptor...\n");
memset (buf, 0x11, sizeof (buf));
returned_string = fgets (buf, sizeof (buf) - 1, null);
TEST_VERIFY (returned_string == NULL);
TEST_VERIFY (bytes_read == 0);
printf ("testing closed descriptor...\n");
f = my_open ("hello\n", 7, "r");
fclose (f);
memset (buf, 0x11, sizeof (buf));
returned_string = fgets (buf, sizeof (buf) - 1, f);
TEST_VERIFY (returned_string == NULL);
TEST_VERIFY (bytes_read == 0);
#endif
return 0;
}
#include <support/test-driver.c>