glibc/libio/tst-freopen.c
Martin Sebor c1760eaf3b Enable support for GCC 11 -Wmismatched-dealloc.
To help detect common kinds of memory (and other resource) management
bugs, GCC 11 adds support for the detection of mismatched calls to
allocation and deallocation functions.  At each call site to a known
deallocation function GCC checks the set of allocation functions
the former can be paired with and, if the two don't match, issues
a -Wmismatched-dealloc warning (something similar happens in C++
for mismatched calls to new and delete).  GCC also uses the same
mechanism to detect attempts to deallocate objects not allocated
by any allocation function (or pointers past the first byte into
allocated objects) by -Wfree-nonheap-object.

This support is enabled for built-in functions like malloc and free.
To extend it beyond those, GCC extends attribute malloc to designate
a deallocation function to which pointers returned from the allocation
function may be passed to deallocate the allocated objects.  Another,
optional argument designates the positional argument to which
the pointer must be passed.

This change is the first step in enabling this extended support for
Glibc.
2021-05-16 15:21:18 -06:00

150 lines
3.8 KiB
C

/* Test freopen with mmap stdio.
Copyright (C) 2002-2021 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Jakub Jelinek <jakub@redhat.com>, 2002.
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 <unistd.h>
#include <support/check.h>
#include <support/temp_file.h>
static int fd;
static char *name;
static void
do_prepare (int argc, char *argv[])
{
fd = create_temp_file ("tst-freopen.", &name);
TEST_VERIFY_EXIT (fd != -1);
}
#define PREPARE do_prepare
/* Basic tests for freopen. */
static void
do_test_basic (void)
{
const char * const test = "Let's test freopen.\n";
char temp[strlen (test) + 1];
FILE *f = fdopen (fd, "w");
if (f == NULL)
FAIL_EXIT1 ("fdopen: %m");
fputs (test, f);
fclose (f);
f = fopen (name, "r");
if (f == NULL)
FAIL_EXIT1 ("fopen: %m");
if (fread (temp, 1, strlen (test), f) != strlen (test))
FAIL_EXIT1 ("fread: %m");
temp [strlen (test)] = '\0';
if (strcmp (test, temp))
FAIL_EXIT1 ("read different string than was written: (%s, %s)",
test, temp);
f = freopen (name, "r+", f);
if (f == NULL)
FAIL_EXIT1 ("freopen: %m");
if (fseek (f, 0, SEEK_SET) != 0)
FAIL_EXIT1 ("fseek: %m");
if (fread (temp, 1, strlen (test), f) != strlen (test))
FAIL_EXIT1 ("fread: %m");
temp [strlen (test)] = '\0';
if (strcmp (test, temp))
FAIL_EXIT1 ("read different string than was written: (%s, %s)",
test, temp);
fclose (f);
}
#if defined __GNUC__ && __GNUC__ >= 11
/* Force an error to detect incorrectly making freopen a deallocator
for its last argument via attribute malloc. The function closes
the stream without deallocating it so either the argument or
the pointer returned from the function (but not both) can be passed
to fclose. */
#pragma GCC diagnostic push
#pragma GCC diagnostic error "-Wmismatched-dealloc"
#endif
/* Verify that freopen returns stream. */
static void
do_test_return_stream (void)
{
FILE *f1 = fopen (name, "r");
if (f1 == NULL)
FAIL_EXIT1 ("fopen: %m");
FILE *f2 = freopen (name, "r+", f1);
if (f2 == NULL)
FAIL_EXIT1 ("freopen: %m");
/* Verify that freopen isn't declared with the no-argument attribute
malloc (which could let GCC fold the inequality to false). */
if (f1 != f2)
FAIL_EXIT1 ("freopen returned a different stream");
/* This shouldn't trigger -Wmismatched-dealloc. */
fclose (f1);
}
#if defined __GNUC__ && __GNUC__ >= 11
/* Pop -Wmismatched-dealloc set to error above. */
# pragma GCC diagnostic pop
#endif
/* Test for BZ#21398, where it tries to freopen stdio after the close
of its file descriptor. */
static void
do_test_bz21398 (void)
{
(void) close (STDIN_FILENO);
FILE *f = freopen (name, "r", stdin);
if (f == NULL)
FAIL_EXIT1 ("freopen: %m");
TEST_VERIFY_EXIT (ferror (f) == 0);
char buf[128];
char *ret = fgets (buf, sizeof (buf), stdin);
TEST_VERIFY_EXIT (ret != NULL);
TEST_VERIFY_EXIT (ferror (f) == 0);
}
static int
do_test (void)
{
do_test_basic ();
do_test_bz21398 ();
do_test_return_stream ();
return 0;
}
#include <support/test-driver.c>