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use crate::old::snapshot_0::hostcalls_impl::PathGet;
use crate::old::snapshot_0::wasi::{WasiError, WasiResult};
use std::os::unix::prelude::AsRawFd;
pub(crate) fn path_unlink_file(resolved: PathGet) -> WasiResult<()> {
use yanix::file::{unlinkat, AtFlags};
match unsafe {
unlinkat(
resolved.dirfd().as_raw_fd(),
resolved.path(),
AtFlags::empty(),
)
} {
Err(err) => {
let raw_errno = err.raw_os_error().unwrap();
// Non-Linux implementations may return EPERM when attempting to remove a
// directory without REMOVEDIR. While that's what POSIX specifies, it's
// less useful. Adjust this to EISDIR. It doesn't matter that this is not
// atomic with the unlinkat, because if the file is removed and a directory
// is created before fstatat sees it, we're racing with that change anyway
// and unlinkat could have legitimately seen the directory if the race had
// turned out differently.
use yanix::file::{fstatat, FileType};
if raw_errno == libc::EPERM {
match unsafe {
fstatat(
resolved.dirfd().as_raw_fd(),
resolved.path(),
AtFlags::SYMLINK_NOFOLLOW,
)
} {
Ok(stat) => {
if FileType::from_stat_st_mode(stat.st_mode) == FileType::Directory {
return Err(WasiError::EISDIR);
}
}
Err(err) => {
tracing::debug!("path_unlink_file fstatat error: {:?}", err);
}
}
}
Err(err.into())
}
Ok(()) => Ok(()),
}
}
pub(crate) fn path_symlink(old_path: &str, resolved: PathGet) -> WasiResult<()> {
use yanix::file::{fstatat, symlinkat, AtFlags};
tracing::debug!("path_symlink old_path = {:?}", old_path);
tracing::debug!("path_symlink resolved = {:?}", resolved);
match unsafe { symlinkat(old_path, resolved.dirfd().as_raw_fd(), resolved.path()) } {
Err(err) => {
if err.raw_os_error().unwrap() == libc::ENOTDIR {
// On BSD, symlinkat returns ENOTDIR when it should in fact
// return a EEXIST. It seems that it gets confused with by
// the trailing slash in the target path. Thus, we strip
// the trailing slash and check if the path exists, and
// adjust the error code appropriately.
let new_path = resolved.path().trim_end_matches('/');
match unsafe {
fstatat(
resolved.dirfd().as_raw_fd(),
new_path,
AtFlags::SYMLINK_NOFOLLOW,
)
} {
Ok(_) => return Err(WasiError::EEXIST),
Err(err) => {
tracing::debug!("path_symlink fstatat error: {:?}", err);
}
}
}
Err(err.into())
}
Ok(()) => Ok(()),
}
}
pub(crate) fn path_rename(resolved_old: PathGet, resolved_new: PathGet) -> WasiResult<()> {
use yanix::file::{fstatat, renameat, AtFlags};
match unsafe {
renameat(
resolved_old.dirfd().as_raw_fd(),
resolved_old.path(),
resolved_new.dirfd().as_raw_fd(),
resolved_new.path(),
)
} {
Err(err) => {
// Currently, this is verified to be correct on macOS, where
// ENOENT can be returned in case when we try to rename a file
// into a name with a trailing slash. On macOS, if the latter does
// not exist, an ENOENT is thrown, whereas on Linux we observe the
// correct behaviour of throwing an ENOTDIR since the destination is
// indeed not a directory.
//
// TODO
// Verify on other BSD-based OSes.
if err.raw_os_error().unwrap() == libc::ENOENT {
// check if the source path exists
match unsafe {
fstatat(
resolved_old.dirfd().as_raw_fd(),
resolved_old.path(),
AtFlags::SYMLINK_NOFOLLOW,
)
} {
Ok(_) => {
// check if destination contains a trailing slash
if resolved_new.path().contains('/') {
return Err(WasiError::ENOTDIR);
} else {
return Err(WasiError::ENOENT);
}
}
Err(err) => {
tracing::debug!("path_rename fstatat error: {:?}", err);
}
}
}
Err(err.into())
}
Ok(()) => Ok(()),
}
}
pub(crate) mod fd_readdir_impl {
use crate::old::snapshot_0::sys::entry_impl::OsHandle;
use crate::old::snapshot_0::wasi::WasiResult;
use std::sync::{Mutex, MutexGuard};
use yanix::dir::Dir;
pub(crate) fn get_dir_from_os_handle<'a>(
os_handle: &'a mut OsHandle,
) -> WasiResult<MutexGuard<'a, Dir>> {
let dir = match os_handle.dir {
Some(ref mut dir) => dir,
None => {
// We need to duplicate the fd, because `opendir(3)`:
// Upon successful return from fdopendir(), the file descriptor is under
// control of the system, and if any attempt is made to close the file
// descriptor, or to modify the state of the associated description other
// than by means of closedir(), readdir(), readdir_r(), or rewinddir(),
// the behaviour is undefined.
let fd = (*os_handle).try_clone()?;
let dir = Dir::from(fd)?;
os_handle.dir.get_or_insert(Mutex::new(dir))
}
};
// Note that from this point on, until the end of the parent scope (i.e., enclosing this
// function), we're locking the `Dir` member of this `OsHandle`.
Ok(dir.lock().unwrap())
}
}