diff options
Diffstat (limited to 'vendor/github.com/tetratelabs/wazero/experimental/sys/fs.go')
| -rw-r--r-- | vendor/github.com/tetratelabs/wazero/experimental/sys/fs.go | 292 |
1 files changed, 292 insertions, 0 deletions
diff --git a/vendor/github.com/tetratelabs/wazero/experimental/sys/fs.go b/vendor/github.com/tetratelabs/wazero/experimental/sys/fs.go new file mode 100644 index 000000000..87810510a --- /dev/null +++ b/vendor/github.com/tetratelabs/wazero/experimental/sys/fs.go @@ -0,0 +1,292 @@ +package sys + +import ( + "io/fs" + + "github.com/tetratelabs/wazero/sys" +) + +// FS is a writeable fs.FS bridge backed by syscall functions needed for ABI +// including WASI. +// +// Implementations should embed UnimplementedFS for forward compatibility. Any +// unsupported method or parameter should return ENO +// +// # Errors +// +// All methods that can return an error return a Errno, which is zero +// on success. +// +// Restricting to Errno matches current WebAssembly host functions, +// which are constrained to well-known error codes. For example, WASI maps syscall +// errors to u32 numeric values. +// +// # Notes +// +// A writable filesystem abstraction is not yet implemented as of Go 1.20. See +// https://github.com/golang/go/issues/45757 +type FS interface { + // OpenFile opens a file. It should be closed via Close on File. + // + // # Errors + // + // A zero Errno is success. The below are expected otherwise: + // - ENOSYS: the implementation does not support this function. + // - EINVAL: `path` or `flag` is invalid. + // - EISDIR: the path was a directory, but flag included O_RDWR or + // O_WRONLY + // - ENOENT: `path` doesn't exist and `flag` doesn't contain O_CREAT. + // + // # Constraints on the returned file + // + // Implementations that can read flags should enforce them regardless of + // the type returned. For example, while os.File implements io.Writer, + // attempts to write to a directory or a file opened with O_RDONLY fail + // with a EBADF. + // + // Some implementations choose whether to enforce read-only opens, namely + // fs.FS. While fs.FS is supported (Adapt), wazero cannot runtime enforce + // open flags. Instead, we encourage good behavior and test our built-in + // implementations. + // + // # Notes + // + // - This is like os.OpenFile, except the path is relative to this file + // system, and Errno is returned instead of os.PathError. + // - Implications of permissions when O_CREAT are described in Chmod notes. + // - This is like `open` in POSIX. See + // https://pubs.opengroup.org/onlinepubs/9699919799/functions/open.html + OpenFile(path string, flag Oflag, perm fs.FileMode) (File, Errno) + + // Lstat gets file status without following symbolic links. + // + // # Errors + // + // A zero Errno is success. The below are expected otherwise: + // - ENOSYS: the implementation does not support this function. + // - ENOENT: `path` doesn't exist. + // + // # Notes + // + // - This is like syscall.Lstat, except the `path` is relative to this + // file system. + // - This is like `lstat` in POSIX. See + // https://pubs.opengroup.org/onlinepubs/9699919799/functions/lstat.html + // - An fs.FileInfo backed implementation sets atim, mtim and ctim to the + // same value. + // - When the path is a symbolic link, the stat returned is for the link, + // not the file it refers to. + Lstat(path string) (sys.Stat_t, Errno) + + // Stat gets file status. + // + // # Errors + // + // A zero Errno is success. The below are expected otherwise: + // - ENOSYS: the implementation does not support this function. + // - ENOENT: `path` doesn't exist. + // + // # Notes + // + // - This is like syscall.Stat, except the `path` is relative to this + // file system. + // - This is like `stat` in POSIX. See + // https://pubs.opengroup.org/onlinepubs/9699919799/functions/stat.html + // - An fs.FileInfo backed implementation sets atim, mtim and ctim to the + // same value. + // - When the path is a symbolic link, the stat returned is for the file + // it refers to. + Stat(path string) (sys.Stat_t, Errno) + + // Mkdir makes a directory. + // + // # Errors + // + // A zero Errno is success. The below are expected otherwise: + // - ENOSYS: the implementation does not support this function. + // - EINVAL: `path` is invalid. + // - EEXIST: `path` exists and is a directory. + // - ENOTDIR: `path` exists and is a file. + // + // # Notes + // + // - This is like syscall.Mkdir, except the `path` is relative to this + // file system. + // - This is like `mkdir` in POSIX. See + // https://pubs.opengroup.org/onlinepubs/9699919799/functions/mkdir.html + // - Implications of permissions are described in Chmod notes. + Mkdir(path string, perm fs.FileMode) Errno + + // Chmod changes the mode of the file. + // + // # Errors + // + // A zero Errno is success. The below are expected otherwise: + // - ENOSYS: the implementation does not support this function. + // - EINVAL: `path` is invalid. + // - ENOENT: `path` does not exist. + // + // # Notes + // + // - This is like syscall.Chmod, except the `path` is relative to this + // file system. + // - This is like `chmod` in POSIX. See + // https://pubs.opengroup.org/onlinepubs/9699919799/functions/chmod.html + // - Windows ignores the execute bit, and any permissions come back as + // group and world. For example, chmod of 0400 reads back as 0444, and + // 0700 0666. Also, permissions on directories aren't supported at all. + Chmod(path string, perm fs.FileMode) Errno + + // Rename renames file or directory. + // + // # Errors + // + // A zero Errno is success. The below are expected otherwise: + // - ENOSYS: the implementation does not support this function. + // - EINVAL: `from` or `to` is invalid. + // - ENOENT: `from` or `to` don't exist. + // - ENOTDIR: `from` is a directory and `to` exists as a file. + // - EISDIR: `from` is a file and `to` exists as a directory. + // - ENOTEMPTY: `both from` and `to` are existing directory, but + // `to` is not empty. + // + // # Notes + // + // - This is like syscall.Rename, except the paths are relative to this + // file system. + // - This is like `rename` in POSIX. See + // https://pubs.opengroup.org/onlinepubs/9699919799/functions/rename.html + // - Windows doesn't let you overwrite an existing directory. + Rename(from, to string) Errno + + // Rmdir removes a directory. + // + // # Errors + // + // A zero Errno is success. The below are expected otherwise: + // - ENOSYS: the implementation does not support this function. + // - EINVAL: `path` is invalid. + // - ENOENT: `path` doesn't exist. + // - ENOTDIR: `path` exists, but isn't a directory. + // - ENOTEMPTY: `path` exists, but isn't empty. + // + // # Notes + // + // - This is like syscall.Rmdir, except the `path` is relative to this + // file system. + // - This is like `rmdir` in POSIX. See + // https://pubs.opengroup.org/onlinepubs/9699919799/functions/rmdir.html + // - As of Go 1.19, Windows maps ENOTDIR to ENOENT. + Rmdir(path string) Errno + + // Unlink removes a directory entry. + // + // # Errors + // + // A zero Errno is success. The below are expected otherwise: + // - ENOSYS: the implementation does not support this function. + // - EINVAL: `path` is invalid. + // - ENOENT: `path` doesn't exist. + // - EISDIR: `path` exists, but is a directory. + // + // # Notes + // + // - This is like syscall.Unlink, except the `path` is relative to this + // file system. + // - This is like `unlink` in POSIX. See + // https://pubs.opengroup.org/onlinepubs/9699919799/functions/unlink.html + // - On Windows, syscall.Unlink doesn't delete symlink to directory unlike other platforms. Implementations might + // want to combine syscall.RemoveDirectory with syscall.Unlink in order to delete such links on Windows. + // See https://learn.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-removedirectorya + Unlink(path string) Errno + + // Link creates a "hard" link from oldPath to newPath, in contrast to a + // soft link (via Symlink). + // + // # Errors + // + // A zero Errno is success. The below are expected otherwise: + // - ENOSYS: the implementation does not support this function. + // - EPERM: `oldPath` is invalid. + // - ENOENT: `oldPath` doesn't exist. + // - EISDIR: `newPath` exists, but is a directory. + // + // # Notes + // + // - This is like syscall.Link, except the `oldPath` is relative to this + // file system. + // - This is like `link` in POSIX. See + // https://pubs.opengroup.org/onlinepubs/9699919799/functions/link.html + Link(oldPath, newPath string) Errno + + // Symlink creates a "soft" link from oldPath to newPath, in contrast to a + // hard link (via Link). + // + // # Errors + // + // A zero Errno is success. The below are expected otherwise: + // - ENOSYS: the implementation does not support this function. + // - EPERM: `oldPath` or `newPath` is invalid. + // - EEXIST: `newPath` exists. + // + // # Notes + // + // - This is like syscall.Symlink, except the `oldPath` is relative to + // this file system. + // - This is like `symlink` in POSIX. See + // https://pubs.opengroup.org/onlinepubs/9699919799/functions/symlink.html + // - Only `newPath` is relative to this file system and `oldPath` is kept + // as-is. That is because the link is only resolved relative to the + // directory when dereferencing it (e.g. ReadLink). + // See https://github.com/bytecodealliance/cap-std/blob/v1.0.4/cap-std/src/fs/dir.rs#L404-L409 + // for how others implement this. + // - Symlinks in Windows requires `SeCreateSymbolicLinkPrivilege`. + // Otherwise, EPERM results. + // See https://learn.microsoft.com/en-us/windows/security/threat-protection/security-policy-settings/create-symbolic-links + Symlink(oldPath, linkName string) Errno + + // Readlink reads the contents of a symbolic link. + // + // # Errors + // + // A zero Errno is success. The below are expected otherwise: + // - ENOSYS: the implementation does not support this function. + // - EINVAL: `path` is invalid. + // + // # Notes + // + // - This is like syscall.Readlink, except the path is relative to this + // filesystem. + // - This is like `readlink` in POSIX. See + // https://pubs.opengroup.org/onlinepubs/9699919799/functions/readlink.html + // - On Windows, the path separator is different from other platforms, + // but to provide consistent results to Wasm, this normalizes to a "/" + // separator. + Readlink(path string) (string, Errno) + + // Utimens set file access and modification times on a path relative to + // this file system, at nanosecond precision. + // + // # Parameters + // + // If the path is a symbolic link, the target of expanding that link is + // updated. + // + // The `atim` and `mtim` parameters refer to access and modification time + // stamps as defined in sys.Stat_t. To retain one or the other, substitute + // it with the pseudo-timestamp UTIME_OMIT. + // + // # Errors + // + // A zero Errno is success. The below are expected otherwise: + // - ENOSYS: the implementation does not support this function. + // - EINVAL: `path` is invalid. + // - EEXIST: `path` exists and is a directory. + // - ENOTDIR: `path` exists and is a file. + // + // # Notes + // + // - This is like syscall.UtimesNano and `utimensat` with `AT_FDCWD` in + // POSIX. See https://pubs.opengroup.org/onlinepubs/9699919799/functions/futimens.html + Utimens(path string, atim, mtim int64) Errno +} |