libcryfs/vendor/scrypt-1.2.0/lib/util/memlimit.c
2016-02-10 00:58:03 +01:00

319 lines
7.6 KiB
C

/*-
* 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.
*/
#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))
memcpy(&sysctlval, sysctlbuf, sizeof(uint64_t));
else if (sysctlbuflen == sizeof(uint32_t))
sysctlval = SIZE_MAX;
else
return (1);
/* Return the sysctl value, but clamp to SIZE_MAX if necessary. */
#if UINT64_MAX > SIZE_MAX
if (sysctlval > SIZE_MAX)
*memlimit = SIZE_MAX;
else
*memlimit = sysctlval;
#else
*memlimit = sysctlval;
#endif
/* Success! */
return (0);
}
#endif
/* If we don't HAVE_STRUCT_SYSINFO, we can't use sysinfo. */
#ifndef HAVE_STRUCT_SYSINFO
#undef HAVE_SYSINFO
#endif
/* If we don't HAVE_STRUCT_SYSINFO_TOTALRAM, we can't use sysinfo. */
#ifndef HAVE_STRUCT_SYSINFO_TOTALRAM
#undef HAVE_SYSINFO
#endif
#ifdef HAVE_SYSINFO
static int
memlimit_sysinfo(size_t * memlimit)
{
struct sysinfo info;
uint64_t totalmem;
/* Get information from the kernel. */
if (sysinfo(&info))
return (1);
totalmem = info.totalram;
/* If we're on a modern kernel, adjust based on mem_unit. */
#ifdef HAVE_STRUCT_SYSINFO_MEM_UNIT
totalmem = totalmem * info.mem_unit;
#endif
/* Return the value, but clamp to SIZE_MAX if necessary. */
#if UINT64_MAX > SIZE_MAX
if (totalmem > SIZE_MAX)
*memlimit = SIZE_MAX;
else
*memlimit = totalmem;
#else
*memlimit = totalmem;
#endif
/* Success! */
return (0);
}
#endif /* HAVE_SYSINFO */
static int
memlimit_rlimit(size_t * memlimit)
{
struct rlimit rl;
uint64_t memrlimit;
/* Find the least of... */
memrlimit = (uint64_t)(-1);
/* ... RLIMIT_AS... */
#ifdef RLIMIT_AS
if (getrlimit(RLIMIT_AS, &rl))
return (1);
if ((rl.rlim_cur != RLIM_INFINITY) &&
((uint64_t)rl.rlim_cur < memrlimit))
memrlimit = rl.rlim_cur;
#endif
/* ... RLIMIT_DATA... */
if (getrlimit(RLIMIT_DATA, &rl))
return (1);
if ((rl.rlim_cur != RLIM_INFINITY) &&
((uint64_t)rl.rlim_cur < memrlimit))
memrlimit = rl.rlim_cur;
/* ... and RLIMIT_RSS. */
#ifdef RLIMIT_RSS
if (getrlimit(RLIMIT_RSS, &rl))
return (1);
if ((rl.rlim_cur != RLIM_INFINITY) &&
((uint64_t)rl.rlim_cur < memrlimit))
memrlimit = rl.rlim_cur;
#endif
/* Return the value, but clamp to SIZE_MAX if necessary. */
#if UINT64_MAX > SIZE_MAX
if (memrlimit > SIZE_MAX)
*memlimit = SIZE_MAX;
else
*memlimit = memrlimit;
#else
*memlimit = memrlimit;
#endif
/* Success! */
return (0);
}
#ifdef _SC_PHYS_PAGES
/* Some systems define _SC_PAGESIZE instead of _SC_PAGE_SIZE. */
#ifndef _SC_PAGE_SIZE
#define _SC_PAGE_SIZE _SC_PAGESIZE
#endif
static int
memlimit_sysconf(size_t * memlimit)
{
long pagesize;
long physpages;
uint64_t totalmem;
/* Set errno to 0 in order to distinguish "no limit" from "error". */
errno = 0;
/* Read the two limits. */
if (((pagesize = sysconf(_SC_PAGE_SIZE)) == -1) ||
((physpages = sysconf(_SC_PHYS_PAGES)) == -1)) {
/* Did an error occur? */
if (errno != 0)
return (1);
/* If not, there is no limit. */
totalmem = (uint64_t)(-1);
} else {
/* Compute the limit. */
totalmem = (uint64_t)(pagesize) * (uint64_t)(physpages);
}
/* Return the value, but clamp to SIZE_MAX if necessary. */
#if UINT64_MAX > SIZE_MAX
if (totalmem > SIZE_MAX)
*memlimit = SIZE_MAX;
else
*memlimit = totalmem;
#else
*memlimit = totalmem;
#endif
/* Success! */
return (0);
}
#endif
int
memtouse(size_t maxmem, double maxmemfrac, size_t * memlimit)
{
size_t usermem_memlimit, memsize_memlimit;
size_t sysinfo_memlimit, rlimit_memlimit;
size_t sysconf_memlimit;
size_t memlimit_min;
size_t memavail;
/* Get memory limits. */
#ifdef HW_USERMEM
if (memlimit_sysctl_hw(&usermem_memlimit, HW_USERMEM))
return (1);
#else
usermem_memlimit = SIZE_MAX;
#endif
#ifdef HW_MEMSIZE
if (memlimit_sysctl_hw(&memsize_memlimit, HW_MEMSIZE))
return (1);
#else
memsize_memlimit = SIZE_MAX;
#endif
#ifdef HAVE_SYSINFO
if (memlimit_sysinfo(&sysinfo_memlimit))
return (1);
#else
sysinfo_memlimit = SIZE_MAX;
#endif
if (memlimit_rlimit(&rlimit_memlimit))
return (1);
#ifdef _SC_PHYS_PAGES
if (memlimit_sysconf(&sysconf_memlimit))
return (1);
#else
sysconf_memlimit = SIZE_MAX;
#endif
#ifdef DEBUG
fprintf(stderr, "Memory limits are %zu %zu %zu %zu %zu\n",
usermem_memlimit, memsize_memlimit,
sysinfo_memlimit, rlimit_memlimit,
sysconf_memlimit);
#endif
/* Find the smallest of them. */
memlimit_min = SIZE_MAX;
if (memlimit_min > usermem_memlimit)
memlimit_min = usermem_memlimit;
if (memlimit_min > memsize_memlimit)
memlimit_min = memsize_memlimit;
if (memlimit_min > sysinfo_memlimit)
memlimit_min = sysinfo_memlimit;
if (memlimit_min > rlimit_memlimit)
memlimit_min = rlimit_memlimit;
if (memlimit_min > sysconf_memlimit)
memlimit_min = sysconf_memlimit;
/* Only use the specified fraction of the available memory. */
if ((maxmemfrac > 0.5) || (maxmemfrac == 0.0))
maxmemfrac = 0.5;
memavail = maxmemfrac * memlimit_min;
/* Don't use more than the specified maximum. */
if ((maxmem > 0) && (memavail > maxmem))
memavail = maxmem;
/* But always allow at least 1 MiB. */
if (memavail < 1048576)
memavail = 1048576;
#ifdef DEBUG
fprintf(stderr, "Allowing up to %zu memory to be used\n", memavail);
#endif
/* Return limit via the provided pointer. */
*memlimit = memavail;
return (0);
}