cosmopolitan/libc/runtime/munmap.c

51 lines
3.0 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney │
│ │
│ 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; version 2 of the License. │
│ │
│ 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, write to the Free Software │
│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
│ 02110-1301 USA │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/calls/internal.h"
#include "libc/dce.h"
#include "libc/macros.h"
#include "libc/runtime/memtrack.h"
#include "libc/runtime/runtime.h"
#include "libc/sysv/errfuns.h"
#define IP(X) (intptr_t)(X)
#define ALIGNED(p) (!(IP(p) & (FRAMESIZE - 1)))
#define CANONICAL(p) (-0x800000000000 <= IP(p) && IP(p) <= 0x7fffffffffff)
/**
* Releases memory pages.
*
* @param addr is a pointer within any memory mapped region the process
* has permission to control, such as address ranges returned by
* mmap(), the program image itself, etc.
* @param size is the amount of memory to unmap, which needn't be a
* multiple of FRAMESIZE, and may be a subset of that which was
* mapped previously, and may punch holes in existing mappings,
* but your mileage may vary on windows
* @return 0 on success, or -1 w/ errno
*/
int munmap(void *addr, size_t size) {
int rc;
if (!ALIGNED(addr) || !CANONICAL(addr) || !size) return einval();
size = ROUNDUP(size, FRAMESIZE);
if (UntrackMemoryIntervals(addr, size) == -1) return -1;
if (IsWindows()) return 0;
return munmap$sysv(addr, size);
}