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Write more memory mapping tests

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Microsoft claims to support COW but it's probably not true.
This commit is contained in:
Justine Tunney 2021-02-04 18:24:33 -08:00
parent 74d48f7cb6
commit 2fdc19e7a7
6 changed files with 83 additions and 29 deletions
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10
libc/runtime/directmap.c
View file

@ -28,14 +28,14 @@
* bypassed by calling this function. However the caller is responsible
* for passing the magic memory handle on Windows NT to CloseHandle().
*/
noasan struct DirectMap __mmap(void *addr, size_t size, unsigned prot,
unsigned flags, int fd, int64_t off) {
noasan struct DirectMap __mmap(void *addr, size_t size, int prot, int flags,
int fd, int64_t off) {
if (!IsWindows()) {
return (struct DirectMap){sys_mmap(addr, size, prot, flags, fd, off),
kNtInvalidHandleValue};
} else {
return __sys_mmap_nt(addr, size, prot,
fd != -1 ? g_fds.p[fd].handle : kNtInvalidHandleValue,
off);
return sys_mmap_nt(addr, size, prot, flags,
fd != -1 ? g_fds.p[fd].handle : kNtInvalidHandleValue,
off);
}
}

4
libc/runtime/directmap.h
View file

@ -8,8 +8,8 @@ struct DirectMap {
int64_t maphandle;
};
struct DirectMap __mmap(void *, size_t, unsigned, unsigned, int, int64_t);
struct DirectMap __sys_mmap_nt(void *, size_t, unsigned, int64_t, int64_t);
struct DirectMap __mmap(void *, size_t, int, int, int, int64_t);
struct DirectMap sys_mmap_nt(void *, size_t, int, int, int64_t, int64_t);
COSMOPOLITAN_C_END_
#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */

71
libc/runtime/directmapnt.c
View file

@ -18,35 +18,70 @@
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/calls/calls.h"
#include "libc/calls/internal.h"
#include "libc/macros.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/overlapped.h"
#include "libc/runtime/directmap.h"
#include "libc/sysv/consts/map.h"
#include "libc/sysv/consts/prot.h"
textwindows noasan struct DirectMap __sys_mmap_nt(void *addr, size_t size,
unsigned prot, int64_t handle,
int64_t off) {
textwindows noasan struct DirectMap sys_mmap_nt(void *addr, size_t size,
int prot, int flags,
int64_t handle, int64_t off) {
uint32_t got;
size_t i, upsize;
struct DirectMap dm;
if ((dm.maphandle = CreateFileMappingNuma(
handle, &kNtIsInheritable,
(prot & PROT_WRITE) ? kNtPageExecuteReadwrite : kNtPageExecuteRead,
handle != -1 ? 0 : size >> 32, handle != -1 ? 0 : size, NULL,
kNtNumaNoPreferredNode))) {
if (!(dm.addr = MapViewOfFileExNuma(
dm.maphandle,
(prot & PROT_WRITE)
? kNtFileMapWrite | kNtFileMapExecute | kNtFileMapRead
: kNtFileMapExecute | kNtFileMapRead,
off >> 32, off, size, addr, kNtNumaNoPreferredNode))) {
struct NtOverlapped op;
if ((prot & PROT_WRITE) && (flags & MAP_PRIVATE) && handle != -1) {
/*
* WIN32 claims it can do COW mappings but we still haven't found a
* combination of flags, that'll cause Windows to actually do this!
*/
upsize = ROUNDUP(size, FRAMESIZE);
if ((dm.maphandle = CreateFileMappingNuma(
-1, &kNtIsInheritable, kNtPageExecuteReadwrite, upsize >> 32,
upsize, NULL, kNtNumaNoPreferredNode))) {
if ((dm.addr = MapViewOfFileExNuma(
dm.maphandle, kNtFileMapWrite | kNtFileMapExecute, 0, 0, upsize,
addr, kNtNumaNoPreferredNode))) {
for (i = 0; i < size; i += got) {
got = 0;
op.Internal = 0;
op.InternalHigh = 0;
op.Pointer = (void *)(uintptr_t)i;
op.hEvent = 0;
if (!ReadFile(handle, (char *)dm.addr + i, size - i, &got, &op)) {
break;
}
}
if (i == size) {
return dm;
}
UnmapViewOfFile(dm.addr);
}
CloseHandle(dm.maphandle);
dm.maphandle = kNtInvalidHandleValue;
dm.addr = (void *)(intptr_t)__winerr();
}
} else {
dm.maphandle = kNtInvalidHandleValue;
dm.addr = (void *)(intptr_t)__winerr();
if ((dm.maphandle = CreateFileMappingNuma(
handle, &kNtIsInheritable,
(prot & PROT_WRITE) ? kNtPageExecuteReadwrite : kNtPageExecuteRead,
handle != -1 ? 0 : size >> 32, handle != -1 ? 0 : size, NULL,
kNtNumaNoPreferredNode))) {
if ((dm.addr = MapViewOfFileExNuma(
dm.maphandle,
(prot & PROT_WRITE) ? kNtFileMapWrite | kNtFileMapExecute
: kNtFileMapRead | kNtFileMapExecute,
off >> 32, off, size, addr, kNtNumaNoPreferredNode))) {
return dm;
} else {
CloseHandle(dm.maphandle);
}
}
}
dm.maphandle = kNtInvalidHandleValue;
dm.addr = (void *)(intptr_t)__winerr();
return dm;
}

4
libc/runtime/fork-nt.c
View file

@ -97,7 +97,9 @@ textwindows noasan void WinMainForked(void) {
size = ((uint64_t)(_mmi.p[i].y - _mmi.p[i].x) << 16) + FRAMESIZE;
if (_mmi.p[i].flags & MAP_PRIVATE) {
CloseHandle(_mmi.p[i].h);
_mmi.p[i].h = __sys_mmap_nt(addr, size, _mmi.p[i].prot, -1, 0).maphandle;
_mmi.p[i].h =
sys_mmap_nt(addr, size, _mmi.p[i].prot, _mmi.p[i].flags, -1, 0)
.maphandle;
ReadAll(reader, addr, size);
} else {
MapViewOfFileExNuma(

7
libc/runtime/winmain.greg.c
View file

@ -107,9 +107,10 @@ static noasan textwindows wontreturn void WinMainNew(void) {
*(/*unconst*/ int *)&__hostos = WINDOWS;
addr = NtGetVersion() < kNtVersionWindows10 ? 0xff00000 : 0x777000000000;
size = ROUNDUP(STACKSIZE + sizeof(struct WinArgs), FRAMESIZE);
_mmi.p[0].h = __sys_mmap_nt((char *)addr, size,
PROT_READ | PROT_WRITE | PROT_EXEC, -1, 0)
.maphandle;
_mmi.p[0].h =
sys_mmap_nt((char *)addr, size, PROT_READ | PROT_WRITE | PROT_EXEC,
MAP_PRIVATE, -1, 0)
.maphandle;
_mmi.p[0].x = addr >> 16;
_mmi.p[0].y = (addr >> 16) + ((size >> 16) - 1);
_mmi.p[0].prot = PROT_READ | PROT_WRITE | PROT_EXEC;

16
test/libc/runtime/mmap_test.c
View file

@ -120,6 +120,22 @@ TEST(mmap, fileOffset) {
EXPECT_NE(-1, close(fd));
}
TEST(mmap, mapPrivate_writesDontChangeFile) {
int fd;
char *map, buf[5];
ASSERT_NE(-1, (fd = open("foo", O_CREAT | O_RDWR, 0644)));
EXPECT_NE(-1, ftruncate(fd, FRAMESIZE));
EXPECT_NE(-1, pwrite(fd, "hello", 5, 0));
ASSERT_NE(MAP_FAILED, (map = mmap(NULL, FRAMESIZE, PROT_READ | PROT_WRITE,
MAP_PRIVATE, fd, 0)));
memcpy(map, "there", 5);
EXPECT_NE(-1, msync(map, FRAMESIZE, MS_SYNC));
EXPECT_NE(-1, munmap(map, FRAMESIZE));
EXPECT_NE(-1, pread(fd, buf, 5, 0));
EXPECT_EQ(0, memcmp(buf, "hello", 5), "%#.*s", 5, buf);
EXPECT_NE(-1, close(fd));
}
TEST(isheap, nullPtr) {
ASSERT_FALSE(isheap(NULL));
}