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scrypt-1.2.1/lib/util/memlimit.c  view on Meta::CPAN

/*-
 * Copyright 2009 Colin Percival
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * This file was originally written by Colin Percival as part of the Tarsnap
 * online backup system.
 */

/* We use non-POSIX functionality in this file. */
#undef _POSIX_C_SOURCE

#include "scrypt_platform.h"

#include <sys/types.h>
#include <sys/resource.h>

#ifdef HAVE_SYS_PARAM_H
#include <sys/param.h>
#endif
#ifdef HAVE_SYS_SYSCTL_H
#include <sys/sysctl.h>
#endif
#ifdef HAVE_SYS_SYSINFO_H
#include <sys/sysinfo.h>
#endif

#include <errno.h>
#include <stddef.h>
#include <stdint.h>
#include <string.h>
#include <unistd.h>

#ifdef DEBUG
#include <stdio.h>
#endif

#include "memlimit.h"

/* If we don't have CTL_HW, we can't use HW_USERMEM. */
#ifndef CTL_HW
#undef HW_USERMEM
#endif

#ifdef CTL_HW
static int
memlimit_sysctl_hw(size_t * memlimit, int mibleaf)
{
	int mib[2];
	uint8_t sysctlbuf[8];
	size_t sysctlbuflen = 8;
	uint64_t sysctlval;

	/* Ask the kernel how much RAM we have. */
	mib[0] = CTL_HW;
	mib[1] = mibleaf;
	if (sysctl(mib, 2, sysctlbuf, &sysctlbuflen, NULL, 0))
		return (1);

	/*
	 * If we read 8 bytes out, assume this is a system-endian uint64_t.
	 * If we only read 4 bytes out, the OS is trying to give us a
	 * uint32_t answer -- but given how many systems now have 4GB+ of RAM,
	 * it's probably truncating, and we really can't trust the value we
	 * have returned to us.
	 */
	if (sysctlbuflen == sizeof(uint64_t))