mirror of
https://github.com/jart/cosmopolitan.git
synced 2025-03-03 15:38:22 +00:00
db33973e0a
This is done without using Microsoft's internal APIs. MAP_PRIVATE mappings are copied to the subprocess via a pipe, since Microsoft doesn't want us to have proper COW pages. MAP_SHARED mappings are remapped without needing to do any copying. Global variables need copying along with the stack and the whole heap of anonymous mem. This actually improves the reliability of the redbean http server although one shouldn't expect 10k+ connections on a home computer that isn't running software built to serve like Linux or FreeBSD.
100 lines
4.8 KiB
C
100 lines
4.8 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/assert.h"
|
|
#include "libc/bits/weaken.h"
|
|
#include "libc/calls/calls.h"
|
|
#include "libc/calls/internal.h"
|
|
#include "libc/dce.h"
|
|
#include "libc/log/asan.h"
|
|
#include "libc/macros.h"
|
|
#include "libc/rand/rand.h"
|
|
#include "libc/runtime/directmap.h"
|
|
#include "libc/runtime/memtrack.h"
|
|
#include "libc/runtime/runtime.h"
|
|
#include "libc/str/str.h"
|
|
#include "libc/sysv/consts/map.h"
|
|
#include "libc/sysv/consts/prot.h"
|
|
#include "libc/sysv/errfuns.h"
|
|
|
|
#define IP(X) (intptr_t)(X)
|
|
#define VIP(X) (void *)IP(X)
|
|
#define ADDR(c) (void *)(IP(c) << 16)
|
|
#define ALIGNED(p) (!(IP(p) & (FRAMESIZE - 1)))
|
|
#define CANONICAL(p) (-0x800000000000 <= IP(p) && IP(p) <= 0x7fffffffffff)
|
|
|
|
/**
|
|
* Beseeches system for page-table entries.
|
|
*
|
|
* char *p = mmap(NULL, 65536, PROT_READ | PROT_WRITE,
|
|
* MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
|
|
* munmap(p, 65536);
|
|
*
|
|
* @param addr optionally requests a particular virtual base address,
|
|
* which needs to be 64kb aligned if passed (for NT compatibility)
|
|
* @param size must be >0 and needn't be a multiple of FRAMESIZE
|
|
* @param prot can have PROT_READ, PROT_WRITE, PROT_EXEC, PROT_NONE, etc.
|
|
* @param flags can have MAP_ANONYMOUS, MAP_SHARED, MAP_PRIVATE, etc.
|
|
* @param fd is an open()'d file descriptor whose contents shall be
|
|
* mapped, and is ignored if MAP_ANONYMOUS is specified
|
|
* @param offset specifies absolute byte index of fd's file for mapping,
|
|
* and should be zero if MAP_ANONYMOUS is specified
|
|
* @return virtual base address of new mapping, or MAP_FAILED w/ errno
|
|
*/
|
|
void *mmap(void *addr, size_t size, int prot, int flags, int fd, int64_t off) {
|
|
int i, x, n, a, b;
|
|
struct DirectMap dm;
|
|
if (!size) return VIP(einval());
|
|
if (!ALIGNED(off)) return VIP(einval());
|
|
if (!ALIGNED(addr)) return VIP(einval());
|
|
if (!CANONICAL(addr)) return VIP(einval());
|
|
if (!(!!(flags & MAP_ANONYMOUS) ^ (fd != -1))) return VIP(einval());
|
|
if (!(!!(flags & MAP_PRIVATE) ^ !!(flags & MAP_SHARED))) return VIP(einval());
|
|
if (fd == -1) size = ROUNDUP(size, FRAMESIZE);
|
|
if (flags & MAP_FIXED) {
|
|
if (UntrackMemoryIntervals(addr, size) == -1) {
|
|
return MAP_FAILED;
|
|
}
|
|
} else {
|
|
x = kAutomapStart >> 16;
|
|
n = ROUNDUP(size, FRAMESIZE) >> 16;
|
|
for (i = 0; i < _mmi.i; ++i) {
|
|
if (_mmi.p[i].y < x) continue;
|
|
if (_mmi.p[i].x > x + n - 1) break;
|
|
x = _mmi.p[i].y + 1;
|
|
}
|
|
if (x + n - 1 >= ((kAutomapStart + kAutomapSize) >> 16)) {
|
|
return (void *)(intptr_t)enomem();
|
|
}
|
|
addr = (void *)(intptr_t)((int64_t)x << 16);
|
|
}
|
|
dm = DirectMap(addr, size, prot, flags | MAP_FIXED, fd, off);
|
|
if (dm.addr == MAP_FAILED || dm.addr != addr) {
|
|
return MAP_FAILED;
|
|
}
|
|
a = ROUNDDOWN((intptr_t)addr, FRAMESIZE) >> 16;
|
|
b = ROUNDDOWN((intptr_t)addr + size - 1, FRAMESIZE) >> 16;
|
|
if (TrackMemoryInterval(&_mmi, a, b, dm.maphandle, prot, flags) == -1) {
|
|
abort();
|
|
}
|
|
if (weaken(__asan_map_shadow)) {
|
|
weaken(__asan_map_shadow)(dm.addr, size);
|
|
}
|
|
return dm.addr;
|
|
}
|