thehub/libs/utils/compat/glibc_sanity.cpp

/*
 * This file is part of the Flowee project
 * Copyright (C) 2009-2014 The Bitcoin Core developers
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#if defined(HAVE_CONFIG_H)
#include "config/flowee-config.h"
#endif

#include <cstddef>

#if defined(HAVE_SYS_SELECT_H)
#include <sys/select.h>
#endif

extern "C" void* memcpy(void* a, const void* b, size_t c);
void* memcpy_int(void* a, const void* b, size_t c)
{
    return memcpy(a, b, c);
}

namespace
{
// trigger: Use the memcpy_int wrapper which calls our internal memcpy.
//   A direct call to memcpy may be optimized away by the compiler.
// test: Fill an array with a sequence of integers. memcpy to a new empty array.
//   Verify that the arrays are equal. Use an odd size to decrease the odds of
//   the call being optimized away.
template <unsigned int T>
bool sanity_test_memcpy()
{
    unsigned int memcpy_test[T];
    unsigned int memcpy_verify[T] = {};
    for (unsigned int i = 0; i != T; ++i)
        memcpy_test[i] = i;

    memcpy_int(memcpy_verify, memcpy_test, sizeof(memcpy_test));

    for (unsigned int i = 0; i != T; ++i) {
        if (memcpy_verify[i] != i)
            return false;
    }
    return true;
}

#if defined(HAVE_SYS_SELECT_H)
// trigger: Call FD_SET to trigger __fdelt_chk. FORTIFY_SOURCE must be defined
//   as >0 and optimizations must be set to at least -O2.
// test: Add a file descriptor to an empty fd_set. Verify that it has been
//   correctly added.
bool sanity_test_fdelt()
{
    fd_set fds;
    FD_ZERO(&fds);
    FD_SET(0, &fds);
    return FD_ISSET(0, &fds);
}
#endif

} // anon namespace

bool glibc_sanity_test()
{
#if defined(HAVE_SYS_SELECT_H)
    if (!sanity_test_fdelt())
        return false;
#endif
    return sanity_test_memcpy<1025>();
}