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Incorporate more small improvements

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Justine Tunney 2023-07-23 10:57:18 -07:00
parent 1d4eb08fa1
commit f83eb440f7
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GPG key ID: BE714B4575D6E328
20 changed files with 121 additions and 256 deletions
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45
libc/calls/read-nt.c
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@ -26,6 +26,7 @@
#include "libc/calls/syscall_support-nt.internal.h"
#include "libc/calls/wincrash.internal.h"
#include "libc/intrin/strace.internal.h"
#include "libc/macros.internal.h"
#include "libc/nt/enum/filetype.h"
#include "libc/nt/errors.h"
#include "libc/nt/files.h"
@ -37,13 +38,10 @@
#include "libc/sysv/errfuns.h"
static textwindows ssize_t sys_read_nt_impl(struct Fd *fd, void *data,
size_t size, ssize_t offset) {
bool32 ok;
int64_t p;
uint32_t got, avail;
struct NtOverlapped overlap;
size_t size, int64_t offset) {
// our terrible polling mechanism
// try to poll rather than block
uint32_t avail;
if (GetFileType(fd->handle) == kNtFileTypePipe) {
for (;;) {
if (!PeekNamedPipe(fd->handle, 0, 0, 0, &avail, 0)) break;
@ -63,19 +61,28 @@ static textwindows ssize_t sys_read_nt_impl(struct Fd *fd, void *data,
POLLTRACE("sys_read_nt ready to read");
}
if (offset != -1) {
// windows changes the file pointer even if overlapped is passed
_npassert(SetFilePointerEx(fd->handle, 0, &p, SEEK_CUR));
// perform the read i/o operation
bool32 ok;
uint32_t got;
size = MIN(size, 0x7ffff000);
if (offset == -1) {
// perform simple blocking read
ok = ReadFile(fd->handle, data, size, &got, 0);
} else {
// perform pread()-style read at particular file offset
int64_t position;
// save file pointer which windows clobbers, even for overlapped i/o
if (!SetFilePointerEx(fd->handle, 0, &position, SEEK_CUR)) {
return __winerr(); // fd probably isn't seekable?
}
struct NtOverlapped overlap = {0};
overlap.Pointer = (void *)(uintptr_t)offset;
ok = ReadFile(fd->handle, data, size, 0, &overlap);
if (!ok && GetLastError() == kNtErrorIoPending) ok = true;
if (ok) ok = GetOverlappedResult(fd->handle, &overlap, &got, true);
// restore file pointer which windows clobbers, even on error
_unassert(SetFilePointerEx(fd->handle, position, 0, SEEK_SET));
}
ok = ReadFile(fd->handle, data, _clampio(size), &got,
_offset2overlap(fd->handle, offset, &overlap));
if (offset != -1) {
// windows clobbers file pointer even on error
_npassert(SetFilePointerEx(fd->handle, p, 0, SEEK_SET));
}
if (ok) {
return got;
}
@ -93,7 +100,7 @@ static textwindows ssize_t sys_read_nt_impl(struct Fd *fd, void *data,
}
textwindows ssize_t sys_read_nt(struct Fd *fd, const struct iovec *iov,
size_t iovlen, ssize_t opt_offset) {
size_t iovlen, int64_t opt_offset) {
ssize_t rc;
uint32_t size;
size_t i, total;