From 41893389a6fb6d4d8b181cd90ca58d9d65326f76 Mon Sep 17 00:00:00 2001 From: Chris O'Hara Date: Mon, 8 May 2023 17:06:08 +1000 Subject: [PATCH] syscall: implement wasip1 SetNonblock and IsNonblock Allows for the NONBLOCK file descriptor flag to be set and queried on wasip1. syscall.SetNonblock uses the fd_fdstat_set_flags WASI system call and unix.IsNonblock uses the fd_fdstat_get system call. This is a prerequisite for non-blocking I/O support. Change-Id: I2bf79fd57142b2ec53eed3977d9aac8c6337eb80 Reviewed-on: https://go-review.googlesource.com/c/go/+/493356 Auto-Submit: Johan Brandhorst-Satzkorn Run-TryBot: Johan Brandhorst-Satzkorn Reviewed-by: Julien Fabre TryBot-Result: Gopher Robot Reviewed-by: Johan Brandhorst-Satzkorn Reviewed-by: Cherry Mui Reviewed-by: Ian Lance Taylor Reviewed-by: Achille Roussel --- .../syscall/unix/nonblocking_wasip1.go | 18 +++++++++++++- src/syscall/fs_wasip1.go | 24 +++++++++++++++++++ src/syscall/net_wasip1.go | 4 ---- src/syscall/syscall_wasip1.go | 14 +++++++++++ 4 files changed, 55 insertions(+), 5 deletions(-) diff --git a/src/internal/syscall/unix/nonblocking_wasip1.go b/src/internal/syscall/unix/nonblocking_wasip1.go index 49a2a232bab..208db28c3ef 100644 --- a/src/internal/syscall/unix/nonblocking_wasip1.go +++ b/src/internal/syscall/unix/nonblocking_wasip1.go @@ -6,6 +6,22 @@ package unix +import ( + "syscall" + _ "unsafe" // for go:linkname +) + func IsNonblock(fd int) (nonblocking bool, err error) { - return false, nil + flags, e1 := fd_fdstat_get_flags(fd) + if e1 != nil { + return false, e1 + } + return flags&syscall.FDFLAG_NONBLOCK != 0, nil } + +// This helper is implemented in the syscall package. It means we don't have +// to redefine the fd_fdstat_get host import or the fdstat struct it +// populates. +// +//go:linkname fd_fdstat_get_flags syscall.fd_fdstat_get_flags +func fd_fdstat_get_flags(fd int) (uint32, error) diff --git a/src/syscall/fs_wasip1.go b/src/syscall/fs_wasip1.go index 84c65c070f6..25cabf82343 100644 --- a/src/syscall/fs_wasip1.go +++ b/src/syscall/fs_wasip1.go @@ -255,6 +255,30 @@ func path_open(rootFD int32, dirflags lookupflags, path unsafe.Pointer, pathLen //go:noescape func random_get(buf unsafe.Pointer, bufLen size) Errno +// https://github.com/WebAssembly/WASI/blob/a2b96e81c0586125cc4dc79a5be0b78d9a059925/legacy/preview1/docs.md#-fdstat-record +// fdflags must be at offset 2, hence the uint16 type rather than the +// fdflags (uint32) type. +type fdstat struct { + filetype filetype + fdflags uint16 + rightsBase rights + rightsInheriting rights +} + +//go:wasmimport wasi_snapshot_preview1 fd_fdstat_get +//go:noescape +func fd_fdstat_get(fd int32, buf unsafe.Pointer) Errno + +//go:wasmimport wasi_snapshot_preview1 fd_fdstat_set_flags +//go:noescape +func fd_fdstat_set_flags(fd int32, flags fdflags) Errno + +func fd_fdstat_get_flags(fd int) (uint32, error) { + var stat fdstat + errno := fd_fdstat_get(int32(fd), unsafe.Pointer(&stat)) + return uint32(stat.fdflags), errnoErr(errno) +} + type preopentype = uint8 const ( diff --git a/src/syscall/net_wasip1.go b/src/syscall/net_wasip1.go index d41e873bed2..896dd3e7708 100644 --- a/src/syscall/net_wasip1.go +++ b/src/syscall/net_wasip1.go @@ -122,7 +122,3 @@ func SetWriteDeadline(fd int, t int64) error { func Shutdown(fd int, how int) error { return ENOSYS } - -func SetNonblock(fd int, nonblocking bool) error { - return ENOSYS -} diff --git a/src/syscall/syscall_wasip1.go b/src/syscall/syscall_wasip1.go index 73a461763ab..5d19c000ae6 100644 --- a/src/syscall/syscall_wasip1.go +++ b/src/syscall/syscall_wasip1.go @@ -464,3 +464,17 @@ const ( //go:wasmimport wasi_snapshot_preview1 clock_time_get //go:noescape func clock_time_get(id clockid, precision timestamp, time unsafe.Pointer) Errno + +func SetNonblock(fd int, nonblocking bool) error { + flags, err := fd_fdstat_get_flags(fd) + if err != nil { + return err + } + if nonblocking { + flags |= FDFLAG_NONBLOCK + } else { + flags &^= FDFLAG_NONBLOCK + } + errno := fd_fdstat_set_flags(int32(fd), flags) + return errnoErr(errno) +}