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Make mmap() work better

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- Mapping file offsets now works on Windows
- Mapping stack memory now works on OpenBSD
This commit is contained in:
Justine Tunney 2021-02-03 00:10:12 -08:00
parent 23a14b537c
commit 27c899af56
10 changed files with 71 additions and 56 deletions
Download patch file Download diff file Expand all files Collapse all files

19
libc/calls/open-nt.c
View file

@ -42,16 +42,7 @@ static textwindows int64_t open$nt$impl(int dirfd, const char *path,
char16_t path16[PATH_MAX];
if (__mkntpathat(dirfd, path, flags, path16) == -1) return -1;
if ((handle = CreateFile(
path16,
(flags & 0xf000000f) |
(/* this is needed if we mmap(rwx+cow)
nt is choosy about open() access */
(flags & O_APPEND)
? kNtFileAppendData
: (flags & O_ACCMODE) == O_RDONLY
? kNtGenericExecute | kNtFileGenericRead
: kNtGenericExecute | kNtFileGenericRead |
kNtFileGenericWrite),
path16, flags & 0xf000000f, /* see consts.sh */
(flags & O_EXCL)
? kNtFileShareExclusive
: kNtFileShareRead | kNtFileShareWrite | kNtFileShareDelete,
@ -75,14 +66,6 @@ static textwindows int64_t open$nt$impl(int dirfd, const char *path,
kNtFileFlagBackupSemantics | kNtFileFlagPosixSemantics |
kNtFileAttributeTemporary)))),
0)) != -1) {
if (flags & O_SPARSE) {
/*
* TODO(jart): Can all files be sparse files? That seems to be the
* way Linux behaves out of the box.
* TODO(jart): Wow why does sparse wreak havoc?
*/
DeviceIoControl(handle, kNtFsctlSetSparse, NULL, 0, NULL, 0, &br, NULL);
}
return handle;
} else if (GetLastError() == kNtErrorFileExists &&
((flags & O_CREAT) &&

4
libc/runtime/directmapnt.c
View file

@ -16,6 +16,7 @@
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/calls/calls.h"
#include "libc/calls/internal.h"
#include "libc/nt/enum/filemapflags.h"
#include "libc/nt/enum/pageflags.h"
@ -30,7 +31,8 @@ textwindows struct DirectMap __mmap$nt(void *addr, size_t size, unsigned prot,
if ((dm.maphandle = CreateFileMappingNuma(
handle, &kNtIsInheritable,
(prot & PROT_WRITE) ? kNtPageExecuteReadwrite : kNtPageExecuteRead,
size >> 32, size, NULL, kNtNumaNoPreferredNode))) {
handle != -1 ? 0 : size >> 32, handle != -1 ? 0 : size, NULL,
kNtNumaNoPreferredNode))) {
if (!(dm.addr = MapViewOfFileExNuma(
dm.maphandle,
(prot & PROT_WRITE)

14
libc/runtime/mmap.c
View file

@ -52,13 +52,14 @@
* @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
* @param off specifies absolute byte index of fd's file for mapping,
* should be zero if MAP_ANONYMOUS is specified, and sadly needs
* to be 64kb aligned too
* @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;
int i, x, n, a, b, f;
if (!size) return VIP(einval());
if (!ALIGNED(off)) return VIP(einval());
if (!ALIGNED(addr)) return VIP(einval());
@ -84,7 +85,12 @@ void *mmap(void *addr, size_t size, int prot, int flags, int fd, int64_t off) {
}
addr = (void *)(intptr_t)((int64_t)x << 16);
}
dm = __mmap(addr, size, prot, flags | MAP_FIXED, fd, off);
f = flags | MAP_FIXED;
if (IsOpenbsd() && (f & MAP_GROWSDOWN)) { /* openbsd:dubstack */
dm = __mmap(addr, size, prot, f & ~MAP_GROWSDOWN, fd, off);
if (dm.addr == MAP_FAILED) return MAP_FAILED;
}
dm = __mmap(addr, size, prot, f, fd, off);
if (dm.addr == MAP_FAILED || dm.addr != addr) {
return MAP_FAILED;
}

6
libc/sysv/consts.sh
View file

@ -205,10 +205,10 @@ syscon sig SIGRTMIN 0 0 65 0 0
# │││ │ ┌┴───dwDesiredAccess
# N │││ │ │
# group name GNU/Systemd XNU's Not UNIX FreeBSD OpenBSD T │││┌─┴┐│ Commentary
syscon open O_RDONLY 0 0 0 0 0x80000000 # unix consensus & kNtGenericRead
syscon open O_RDONLY 0 0 0 0 0xA0000000 # unix consensus & kNtGenericRead|kNtGenericExecute
syscon open O_WRONLY 1 1 1 1 0x40000000 # unix consensus & kNtGenericWrite
syscon open O_RDWR 2 2 2 2 0xc0000000 # unix consensus & kNtGenericRead|kNtGenericWrite
syscon open O_ACCMODE 3 3 3 3 0xc0000000 # O_RDONLY|O_WRONLY|O_RDWR
syscon open O_RDWR 2 2 2 2 0xE0000000 # unix consensus & kNtGenericRead|kNtGenericWrite|kNtGenericExecute
syscon open O_ACCMODE 3 3 3 3 0xE0000000 # O_RDONLY|O_WRONLY|O_RDWR
syscon open O_APPEND 0x0400 8 8 8 0x00000004 # bsd consensus & kNtFileAppendData; won't pose issues w/ mknod(S_IFIFO)
syscon open O_CREAT 0x40 0x0200 0x0200 0x0200 0x00000040 # bsd consensus & NT faked as Linux
syscon open O_EXCL 0x80 0x0800 0x0800 0x0800 0x00000080 # bsd consensus & NT faked as Linux

2
libc/sysv/consts/O_ACCMODE.s
View file

@ -1,2 +1,2 @@
.include "libc/sysv/consts/syscon.inc"
.syscon open O_ACCMODE 3 3 3 3 0xc0000000
.syscon open O_ACCMODE 3 3 3 3 0xE0000000

2
libc/sysv/consts/O_RDONLY.s
View file

@ -1,2 +1,2 @@
.include "libc/sysv/consts/syscon.inc"
.syscon open O_RDONLY 0 0 0 0 0x80000000
.syscon open O_RDONLY 0 0 0 0 0xA0000000

2
libc/sysv/consts/O_RDWR.s
View file

@ -1,2 +1,2 @@
.include "libc/sysv/consts/syscon.inc"
.syscon open O_RDWR 2 2 2 2 0xc0000000
.syscon open O_RDWR 2 2 2 2 0xE0000000