mirror of
https://github.com/superseriousbusiness/gotosocial.git
synced 2024-12-23 18:52:11 +00:00
1e7b32490d
This allows for building GoToSocial with [SQLite transpiled to WASM](https://github.com/ncruces/go-sqlite3) and accessed through [Wazero](https://wazero.io/).
176 lines
6.3 KiB
Go
176 lines
6.3 KiB
Go
package sysfs
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import (
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"errors"
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"syscall"
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"unsafe"
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"github.com/tetratelabs/wazero/experimental/sys"
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)
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const (
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nonBlockingFileReadSupported = true
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nonBlockingFileWriteSupported = false
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_ERROR_IO_INCOMPLETE = syscall.Errno(996)
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)
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var kernel32 = syscall.NewLazyDLL("kernel32.dll")
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// procPeekNamedPipe is the syscall.LazyProc in kernel32 for PeekNamedPipe
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var (
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// procPeekNamedPipe is the syscall.LazyProc in kernel32 for PeekNamedPipe
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procPeekNamedPipe = kernel32.NewProc("PeekNamedPipe")
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// procGetOverlappedResult is the syscall.LazyProc in kernel32 for GetOverlappedResult
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procGetOverlappedResult = kernel32.NewProc("GetOverlappedResult")
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// procCreateEventW is the syscall.LazyProc in kernel32 for CreateEventW
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procCreateEventW = kernel32.NewProc("CreateEventW")
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)
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// readFd returns ENOSYS on unsupported platforms.
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//
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// PeekNamedPipe: https://learn.microsoft.com/en-us/windows/win32/api/namedpipeapi/nf-namedpipeapi-peeknamedpipe
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// "GetFileType can assist in determining what device type the handle refers to. A console handle presents as FILE_TYPE_CHAR."
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// https://learn.microsoft.com/en-us/windows/console/console-handles
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func readFd(fd uintptr, buf []byte) (int, sys.Errno) {
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handle := syscall.Handle(fd)
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fileType, err := syscall.GetFileType(handle)
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if err != nil {
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return 0, sys.UnwrapOSError(err)
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}
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if fileType&syscall.FILE_TYPE_CHAR == 0 {
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return -1, sys.ENOSYS
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}
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n, errno := peekNamedPipe(handle)
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if errno == syscall.ERROR_BROKEN_PIPE {
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return 0, 0
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}
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if n == 0 {
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return -1, sys.EAGAIN
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}
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un, err := syscall.Read(handle, buf[0:n])
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return un, sys.UnwrapOSError(err)
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}
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func writeFd(fd uintptr, buf []byte) (int, sys.Errno) {
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return -1, sys.ENOSYS
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}
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func readSocket(h uintptr, buf []byte) (int, sys.Errno) {
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// Poll the socket to ensure that we never perform a blocking/overlapped Read.
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//
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// When the socket is closed by the remote peer, wsaPoll will return n=1 and
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// errno=0, and syscall.ReadFile will return n=0 and errno=0 -- which indicates
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// io.EOF.
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if n, errno := wsaPoll(
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[]pollFd{newPollFd(h, _POLLIN, 0)}, 0); !errors.Is(errno, sys.Errno(0)) {
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return 0, sys.UnwrapOSError(errno)
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} else if n <= 0 {
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return 0, sys.EAGAIN
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}
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// Properly use overlapped result.
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//
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// If hFile was opened with FILE_FLAG_OVERLAPPED, the following conditions are in effect:
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// - The lpOverlapped parameter must point to a valid and unique OVERLAPPED structure,
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// otherwise the function can incorrectly report that the read operation is complete.
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// - The lpNumberOfBytesRead parameter should be set to NULL. Use the GetOverlappedResult
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// function to get the actual number of bytes read. If the hFile parameter is associated
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// with an I/O completion port, you can also get the number of bytes read by calling the
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// GetQueuedCompletionStatus function.
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//
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// We are currently skipping checking if hFile was opened with FILE_FLAG_OVERLAPPED but using
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// both lpOverlapped and lpNumberOfBytesRead.
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var overlapped syscall.Overlapped
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// Create an event to wait on.
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if hEvent, err := createEventW(nil, true, false, nil); err != 0 {
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return 0, sys.UnwrapOSError(err)
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} else {
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overlapped.HEvent = syscall.Handle(hEvent)
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}
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var done uint32
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errno := syscall.ReadFile(syscall.Handle(h), buf, &done, &overlapped)
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if errors.Is(errno, syscall.ERROR_IO_PENDING) {
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errno = syscall.CancelIo(syscall.Handle(h))
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if errno != nil {
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return 0, sys.UnwrapOSError(errno) // This is a fatal error. CancelIo failed.
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}
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done, errno = getOverlappedResult(syscall.Handle(h), &overlapped, true) // wait for I/O to complete(cancel or finish). Overwrite done and errno.
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if errors.Is(errno, syscall.ERROR_OPERATION_ABORTED) {
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return int(done), sys.EAGAIN // This is one of the expected behavior, I/O was cancelled(completed) before finished.
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}
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}
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return int(done), sys.UnwrapOSError(errno)
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}
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func writeSocket(fd uintptr, buf []byte) (int, sys.Errno) {
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var done uint32
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var overlapped syscall.Overlapped
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errno := syscall.WriteFile(syscall.Handle(fd), buf, &done, &overlapped)
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if errors.Is(errno, syscall.ERROR_IO_PENDING) {
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errno = syscall.EAGAIN
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}
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return int(done), sys.UnwrapOSError(errno)
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}
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// peekNamedPipe partially exposes PeekNamedPipe from the Win32 API
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// see https://learn.microsoft.com/en-us/windows/win32/api/namedpipeapi/nf-namedpipeapi-peeknamedpipe
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func peekNamedPipe(handle syscall.Handle) (uint32, syscall.Errno) {
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var totalBytesAvail uint32
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totalBytesPtr := unsafe.Pointer(&totalBytesAvail)
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_, _, errno := syscall.SyscallN(
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procPeekNamedPipe.Addr(),
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uintptr(handle), // [in] HANDLE hNamedPipe,
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0, // [out, optional] LPVOID lpBuffer,
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0, // [in] DWORD nBufferSize,
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0, // [out, optional] LPDWORD lpBytesRead
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uintptr(totalBytesPtr), // [out, optional] LPDWORD lpTotalBytesAvail,
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0) // [out, optional] LPDWORD lpBytesLeftThisMessage
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return totalBytesAvail, errno
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}
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func rmdir(path string) sys.Errno {
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err := syscall.Rmdir(path)
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return sys.UnwrapOSError(err)
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}
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func getOverlappedResult(handle syscall.Handle, overlapped *syscall.Overlapped, wait bool) (uint32, syscall.Errno) {
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var totalBytesAvail uint32
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var bwait uintptr
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if wait {
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bwait = 0xFFFFFFFF
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}
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totalBytesPtr := unsafe.Pointer(&totalBytesAvail)
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_, _, errno := syscall.SyscallN(
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procGetOverlappedResult.Addr(),
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uintptr(handle), // [in] HANDLE hFile,
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uintptr(unsafe.Pointer(overlapped)), // [in] LPOVERLAPPED lpOverlapped,
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uintptr(totalBytesPtr), // [out] LPDWORD lpNumberOfBytesTransferred,
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bwait) // [in] BOOL bWait
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return totalBytesAvail, errno
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}
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func createEventW(lpEventAttributes *syscall.SecurityAttributes, bManualReset bool, bInitialState bool, lpName *uint16) (uintptr, syscall.Errno) {
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var manualReset uintptr
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var initialState uintptr
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if bManualReset {
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manualReset = 1
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}
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if bInitialState {
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initialState = 1
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}
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handle, _, errno := syscall.SyscallN(
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procCreateEventW.Addr(),
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uintptr(unsafe.Pointer(lpEventAttributes)), // [in] LPSECURITY_ATTRIBUTES lpEventAttributes,
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manualReset, // [in] BOOL bManualReset,
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initialState, // [in] BOOL bInitialState,
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uintptr(unsafe.Pointer(lpName)), // [in, opt]LPCWSTR lpName,
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)
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return handle, errno
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}
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