T0b1/wasmtime
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

path_get refactor and implementation of missing path_ hostcalls on Windows (#41)

Browse Source 
* Move path_get outside of sys module

* Add implementation of readlinkat

* Clean up path_open; use OpenOptions as much as possible

* Enable close_preopen test

* Implement path_create_directory; fix path_open

* Refactor path concatenation onto a descriptor

* Implement path_remove_directory

* Implement path_unlink_file

* Rewrite path_open using specific access mask

* Fix error mapping when unlinking file

* Fix readlinkat to pass nofollow_errors testcase

* Clean up winerror to WASI conversion

* Spoof creating dangling symlinks on windows (hacky!)

* Add positive testcase for readlink

* Implement path_readlink (for nonzero buffers for now)

* Clean up

* Add Symlink struct immitating *nix symlink

* Fix path_readlink

* Augment interesting_paths testcase with trailing slashes example

* Encapsulate path_get return value as PathGet struct

* Remove dangling symlink emulation

* Extract dangling symlinks into its own testcase

This way, we can re-enable nofollow_errors testcase
on Windows also.

* Return __WASI_ENOTCAPABLE if user lacks perms to symlink
This commit is contained in:
Jakub Konka
2019-08-08 17:06:01 +02:00
committed by GitHub
parent 8ea7a983d8
commit e18175c556
19 changed files with 757 additions and 690 deletions
Download Patch File Download Diff File Expand all files Collapse all files

91
src/hostcalls_impl/fs.rs
View File

@@ -1,7 +1,10 @@
#![allow(non_camel_case_types)]
use super::fs_helpers::path_get;
use crate::ctx::WasiCtx;
use crate::fdentry::{Descriptor, FdEntry};
use crate::memory::*;
use crate::sys::fdentry_impl::determine_type_rights;
use crate::sys::hostcalls_impl::fs_helpers::path_open_rights;
use crate::sys::{errno_from_host, host_impl, hostcalls_impl};
use crate::{host, wasm32, Result};
use log::trace;
@@ -242,9 +245,10 @@ pub(crate) fn fd_seek(
host::__WASI_WHENCE_SET => SeekFrom::Start(offset as u64),
_ => return Err(host::__WASI_EINVAL),
};
let host_newoffset = fd
.seek(pos)
.map_err(|err| err.raw_os_error().map_or(host::__WASI_EIO, errno_from_host))?;
let host_newoffset = fd.seek(pos).map_err(|err| {
log::debug!("fd_seek error={:?}", err);
err.raw_os_error().map_or(host::__WASI_EIO, errno_from_host)
})?;
trace!(" | *newoffset={:?}", host_newoffset);
@@ -487,8 +491,9 @@ pub(crate) fn path_create_directory(
let dirfd = wasi_ctx
.get_fd_entry(dirfd, rights, 0)
.and_then(|fe| fe.fd_object.descriptor.as_file())?;
let resolved = path_get(dirfd, 0, path, false)?;
hostcalls_impl::path_create_directory(dirfd, path)
hostcalls_impl::path_create_directory(resolved)
}
pub(crate) fn path_link(
@@ -529,8 +534,10 @@ pub(crate) fn path_link(
let new_dirfd = wasi_ctx
.get_fd_entry(new_dirfd, host::__WASI_RIGHT_PATH_LINK_TARGET, 0)
.and_then(|fe| fe.fd_object.descriptor.as_file())?;
let resolved_old = path_get(old_dirfd, 0, old_path, false)?;
let resolved_new = path_get(new_dirfd, 0, new_path, false)?;
hostcalls_impl::path_link(old_dirfd, new_dirfd, old_path, new_path)
hostcalls_impl::path_link(resolved_old, resolved_new)
}
pub(crate) fn path_open(
@@ -559,6 +566,9 @@ pub(crate) fn path_open(
fd_out_ptr
);
// pre-encode fd_out_ptr to -1 in case of error in opening a path
enc_fd_byref(memory, fd_out_ptr, wasm32::__wasi_fd_t::max_value())?;
let dirfd = dec_fd(dirfd);
let dirflags = dec_lookupflags(dirflags);
let oflags = dec_oflags(oflags);
@@ -566,6 +576,17 @@ pub(crate) fn path_open(
let fs_rights_inheriting = dec_rights(fs_rights_inheriting);
let fs_flags = dec_fdflags(fs_flags);
let path = dec_slice_of::<u8>(memory, path_ptr, path_len).and_then(host::path_from_slice)?;
trace!(" | (path_ptr,path_len)='{}'", path);
let (needed_base, needed_inheriting) =
path_open_rights(fs_rights_base, fs_rights_inheriting, oflags, fs_flags);
let dirfd = wasi_ctx
.get_fd_entry(dirfd, needed_base, needed_inheriting)
.and_then(|fe| fe.fd_object.descriptor.as_file())?;
let resolved = path_get(dirfd, dirflags, path, oflags & host::__WASI_O_CREAT != 0)?;
// which open mode do we need?
let read = fs_rights_base & (host::__WASI_RIGHT_FD_READ | host::__WASI_RIGHT_FD_READDIR) != 0;
let write = fs_rights_base
@@ -575,37 +596,18 @@ pub(crate) fn path_open(
| host::__WASI_RIGHT_FD_FILESTAT_SET_SIZE)
!= 0;
// which rights are needed on the dirfd?
let needed_base = host::__WASI_RIGHT_PATH_OPEN;
let needed_inheriting = fs_rights_base | fs_rights_inheriting;
let fd = hostcalls_impl::path_open(resolved, read, write, oflags, fs_flags)?;
let path = dec_slice_of::<u8>(memory, path_ptr, path_len).and_then(host::path_from_slice)?;
// Determine the type of the new file descriptor and which rights contradict with this type
let (_ty, max_base, max_inheriting) = determine_type_rights(&fd)?;
let mut fe = FdEntry::from(fd)?;
fe.rights_base &= max_base;
fe.rights_inheriting &= max_inheriting;
let guest_fd = wasi_ctx.insert_fd_entry(fe)?;
trace!(" | (path_ptr,path_len)='{}'", path);
trace!(" | *fd={:?}", guest_fd);
hostcalls_impl::path_open(
wasi_ctx,
dirfd,
dirflags,
path,
oflags,
read,
write,
needed_base,
needed_inheriting,
fs_flags,
)
.and_then(|fe| {
let guest_fd = wasi_ctx.insert_fd_entry(fe)?;
trace!(" | *fd={:?}", guest_fd);
enc_fd_byref(memory, fd_out_ptr, guest_fd)
})
.or_else(|err| {
enc_fd_byref(memory, fd_out_ptr, wasm32::__wasi_fd_t::max_value())?;
Err(err)
})
enc_fd_byref(memory, fd_out_ptr, guest_fd)
}
pub(crate) fn fd_readdir(
@@ -676,10 +678,11 @@ pub(crate) fn path_readlink(
let dirfd = wasi_ctx
.get_fd_entry(dirfd, host::__WASI_RIGHT_PATH_READLINK, 0)
.and_then(|fe| fe.fd_object.descriptor.as_file())?;
let resolved = path_get(dirfd, 0, &path, false)?;
let mut buf = dec_slice_of_mut::<u8>(memory, buf_ptr, buf_len)?;
let host_bufused = hostcalls_impl::path_readlink(dirfd, &path, &mut buf)?;
let host_bufused = hostcalls_impl::path_readlink(resolved, &mut buf)?;
trace!(" | (buf_ptr,*buf_used)={:?}", buf);
trace!(" | *buf_used={:?}", host_bufused);
@@ -723,8 +726,10 @@ pub(crate) fn path_rename(
let new_dirfd = wasi_ctx
.get_fd_entry(new_dirfd, host::__WASI_RIGHT_PATH_RENAME_TARGET, 0)
.and_then(|fe| fe.fd_object.descriptor.as_file())?;
let resolved_old = path_get(old_dirfd, 0, old_path, false)?;
let resolved_new = path_get(new_dirfd, 0, new_path, false)?;
hostcalls_impl::path_rename(old_dirfd, old_path, new_dirfd, new_path)
hostcalls_impl::path_rename(resolved_old, resolved_new)
}
pub(crate) fn fd_filestat_get(
@@ -825,8 +830,8 @@ pub(crate) fn path_filestat_get(
let dirfd = wasi_ctx
.get_fd_entry(dirfd, host::__WASI_RIGHT_PATH_FILESTAT_GET, 0)
.and_then(|fe| fe.fd_object.descriptor.as_file())?;
let host_filestat = hostcalls_impl::path_filestat_get(dirfd, dirflags, path)?;
let resolved = path_get(dirfd, dirflags, path, false)?;
let host_filestat = hostcalls_impl::path_filestat_get(resolved, dirflags)?;
trace!(" | *filestat_ptr={:?}", host_filestat);
@@ -867,8 +872,9 @@ pub(crate) fn path_filestat_set_times(
let dirfd = wasi_ctx
.get_fd_entry(dirfd, host::__WASI_RIGHT_PATH_FILESTAT_SET_TIMES, 0)
.and_then(|fe| fe.fd_object.descriptor.as_file())?;
let resolved = path_get(dirfd, dirflags, path, false)?;
hostcalls_impl::path_filestat_set_times(dirfd, dirflags, path, st_atim, st_mtim, fst_flags)
hostcalls_impl::path_filestat_set_times(resolved, dirflags, st_atim, st_mtim, fst_flags)
}
pub(crate) fn path_symlink(
@@ -901,8 +907,9 @@ pub(crate) fn path_symlink(
let dirfd = wasi_ctx
.get_fd_entry(dirfd, host::__WASI_RIGHT_PATH_SYMLINK, 0)
.and_then(|fe| fe.fd_object.descriptor.as_file())?;
let resolved_new = path_get(dirfd, 0, new_path, false)?;
hostcalls_impl::path_symlink(dirfd, old_path, new_path)
hostcalls_impl::path_symlink(old_path, resolved_new)
}
pub(crate) fn path_unlink_file(
@@ -927,8 +934,9 @@ pub(crate) fn path_unlink_file(
let dirfd = wasi_ctx
.get_fd_entry(dirfd, host::__WASI_RIGHT_PATH_UNLINK_FILE, 0)
.and_then(|fe| fe.fd_object.descriptor.as_file())?;
let resolved = path_get(dirfd, 0, path, false)?;
hostcalls_impl::path_unlink_file(dirfd, path)
hostcalls_impl::path_unlink_file(resolved)
}
pub(crate) fn path_remove_directory(
@@ -953,8 +961,9 @@ pub(crate) fn path_remove_directory(
let dirfd = wasi_ctx
.get_fd_entry(dirfd, host::__WASI_RIGHT_PATH_REMOVE_DIRECTORY, 0)
.and_then(|fe| fe.fd_object.descriptor.as_file())?;
let resolved = path_get(dirfd, 0, path, false)?;
hostcalls_impl::path_remove_directory(dirfd, path)
hostcalls_impl::path_remove_directory(resolved)
}
pub(crate) fn fd_prestat_get(