cosmopolitan/libc/calls/directmap-nt.c
Justine Tunney adac64a52b Reduce makefile dependencies by 10%
The includes in libc/calls/calls.h have now been refactored so that
functions with struct parameters are declared in libc/calls/struct/
2022-06-08 20:01:28 -07:00

99 lines
4.5 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 │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/assert.h"
#include "libc/calls/internal.h"
#include "libc/calls/state.internal.h"
#include "libc/nt/enum/filemapflags.h"
#include "libc/nt/enum/pageflags.h"
#include "libc/nt/memory.h"
#include "libc/nt/runtime.h"
#include "libc/nt/struct/processmemorycounters.h"
#include "libc/nt/struct/securityattributes.h"
#include "libc/runtime/directmap.internal.h"
#include "libc/sysv/consts/map.h"
#include "libc/sysv/consts/o.h"
textwindows struct DirectMap sys_mmap_nt(void *addr, size_t size, int prot,
int flags, int fd, int64_t off) {
size_t i;
bool iscow;
int64_t handle;
uint32_t oldprot;
struct DirectMap dm;
struct ProtectNt fl;
const struct NtSecurityAttributes *sec;
struct NtProcessMemoryCountersEx memcount;
if (fd != -1) {
handle = g_fds.p[fd].handle;
} else {
handle = kNtInvalidHandleValue;
}
if ((flags & MAP_TYPE) != MAP_SHARED) {
sec = 0; // MAP_PRIVATE isn't inherited across fork()
} else {
sec = &kNtIsInheritable; // MAP_SHARED gives us zero-copy fork()
}
// nt will whine under many circumstances if we change the execute bit
// later using mprotect(). the workaround is to always request execute
// and then virtualprotect() it away until we actually need it. please
// note that open-nt.c always requests an kNtGenericExecute accessmask
iscow = false;
if (handle != -1) {
if ((flags & MAP_TYPE) != MAP_SHARED) {
// windows has cow pages but they can't propagate across fork()
// that means we only get copy-on-write for the root process :(
fl = (struct ProtectNt){kNtPageExecuteWritecopy,
kNtFileMapCopy | kNtFileMapExecute};
iscow = true;
} else {
if ((g_fds.p[fd].flags & O_ACCMODE) == O_RDONLY) {
fl = (struct ProtectNt){kNtPageExecuteRead,
kNtFileMapRead | kNtFileMapExecute};
} else {
fl = (struct ProtectNt){kNtPageExecuteReadwrite,
kNtFileMapWrite | kNtFileMapExecute};
}
}
} else {
assert(flags & MAP_ANONYMOUS);
fl = (struct ProtectNt){kNtPageExecuteReadwrite,
kNtFileMapWrite | kNtFileMapExecute};
}
if ((dm.maphandle = CreateFileMapping(handle, sec, fl.flags1,
(size + off) >> 32, (size + off), 0))) {
if ((dm.addr = MapViewOfFileEx(dm.maphandle, fl.flags2, off >> 32, off,
size, addr))) {
if (VirtualProtect(addr, size, __prot2nt(prot, iscow), &oldprot)) {
return dm;
} else {
return dm;
UnmapViewOfFile(dm.addr);
}
}
CloseHandle(dm.maphandle);
}
dm.maphandle = kNtInvalidHandleValue;
dm.addr = (void *)(intptr_t)-1;
return dm;
}