Documentation
¶
Index ¶
- Constants
- Variables
- func FdReader(ctx context.Context, sysCtx *Context, fd uint32) io.Reader
- func FdWriter(ctx context.Context, sysCtx *Context, fd uint32) io.Writer
- type Context
- func (c *Context) Args() []string
- func (c *Context) ArgsSize() uint32
- func (c *Context) Environ() []string
- func (c *Context) EnvironSize() uint32
- func (c *Context) FS(ctx context.Context) *FSContext
- func (c *Context) Nanosleep(ctx context.Context, ns int64)
- func (c *Context) Nanotime(ctx context.Context) int64
- func (c *Context) NanotimeResolution() sys.ClockResolution
- func (c *Context) RandSource() io.Reader
- func (c *Context) Stderr() io.Writer
- func (c *Context) Stdin() io.Reader
- func (c *Context) Stdout() io.Writer
- func (c *Context) Walltime(ctx context.Context) (sec int64, nsec int32)
- func (c *Context) WalltimeResolution() sys.ClockResolution
- type FSContext
- type FSKey
- type FileEntry
- type ReadDir
Constants ¶
const ( FdStdin = iota FdStdout FdStderr )
Variables ¶
var EmptyFS = &emptyFS{}
EmptyFS is exported to special-case an empty file system.
Functions ¶
Types ¶
type Context ¶
type Context struct {
// contains filtered or unexported fields
}
Context holds module-scoped system resources currently only supported by built-in host functions.
func DefaultContext ¶
DefaultContext returns Context with no values set except a possibly nil fs.FS
func NewContext ¶
func NewContext( max uint32, args, environ []string, stdin io.Reader, stdout, stderr io.Writer, randSource io.Reader, walltime *sys.Walltime, walltimeResolution sys.ClockResolution, nanotime *sys.Nanotime, nanotimeResolution sys.ClockResolution, nanosleep *sys.Nanosleep, fs fs.FS, ) (sysCtx *Context, err error)
NewContext is a factory function which helps avoid needing to know defaults or exporting all fields. Note: max is exposed for testing. max is only used for env/args validation.
func (*Context) Args ¶
Args is like os.Args and defaults to nil.
Note: The count will never be more than math.MaxUint32. See wazero.ModuleConfig WithArgs
func (*Context) ArgsSize ¶
ArgsSize is the size to encode Args as Null-terminated strings.
Note: To get the size without null-terminators, subtract the length of Args from this value. See wazero.ModuleConfig WithArgs See https://en.wikipedia.org/wiki/Null-terminated_string
func (*Context) Environ ¶
Environ are "key=value" entries like os.Environ and default to nil.
Note: The count will never be more than math.MaxUint32. See wazero.ModuleConfig WithEnv
func (*Context) EnvironSize ¶
EnvironSize is the size to encode Environ as Null-terminated strings.
Note: To get the size without null-terminators, subtract the length of Environ from this value. See wazero.ModuleConfig WithEnv See https://en.wikipedia.org/wiki/Null-terminated_string
func (*Context) NanotimeResolution ¶
func (c *Context) NanotimeResolution() sys.ClockResolution
NanotimeResolution returns resolution of Nanotime.
func (*Context) RandSource ¶
RandSource is a source of random bytes and defaults to a deterministic source. see wazero.ModuleConfig WithRandSource
func (*Context) Stderr ¶
Stderr is like exec.Cmd Stderr and defaults to io.Discard. See wazero.ModuleConfig WithStderr
func (*Context) Stdin ¶
Stdin is like exec.Cmd Stdin and defaults to a reader of os.DevNull. See wazero.ModuleConfig WithStdin
func (*Context) Stdout ¶
Stdout is like exec.Cmd Stdout and defaults to io.Discard. See wazero.ModuleConfig WithStdout
func (*Context) WalltimeResolution ¶
func (c *Context) WalltimeResolution() sys.ClockResolution
WalltimeResolution returns resolution of Walltime.
type FSContext ¶
type FSContext struct {
// contains filtered or unexported fields
}
func NewFSContext ¶
NewFSContext creates a FSContext, using the `root` parameter for any paths beginning at "/". If the input is EmptyFS, there is no root filesystem. Otherwise, `root` is assigned file descriptor 3 and the returned context can open files in that file system.
Why file descriptor 3?
While not specified, the most common WASI implementation, wasi-libc, expects POSIX style file descriptor allocation, where the lowest available number is used to open the next file. Since 1 and 2 are taken by stdout and stderr, `root` is assigned 3.
func (*FSContext) CloseFile ¶
CloseFile returns true if a file was opened and closed without error, or false if syscall.EBADF.
func (*FSContext) OpenFile ¶
OpenFile is like syscall.Open and returns the file descriptor of the new file or an error.
TODO: Consider dirflags and oflags. Also, allow non-read-only open based on config about the mount. e.g. allow os.O_RDONLY, os.O_WRONLY, or os.O_RDWR either by config flag or pattern on filename See #390
type FSKey ¶
type FSKey struct{}
FSKey is a context.Context Value key. It allows overriding fs.FS for WASI.
type FileEntry ¶
type FileEntry struct {
// Path was the argument to FSContext.OpenFile
Path string
// File when nil this is the root "/" (fd=3)
File fs.File
// ReadDir is present when this File is a fs.ReadDirFile and `ReadDir`
// was called.
ReadDir *ReadDir
}
FileEntry maps a path to an open file in a file system.
type ReadDir ¶
type ReadDir struct {
// CountRead is the total count of files read including Entries.
CountRead uint64
// Entries is the contents of the last fs.ReadDirFile call. Notably,
// directory listing are not rewindable, so we keep entries around in case
// the caller mis-estimated their buffer and needs a few still cached.
Entries []fs.DirEntry
}
ReadDir is the status of a prior fs.ReadDirFile call.
Source Files