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Some FileDescriptor/FileDescription refactorings #3770

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Merged
merged 4 commits into from
Jul 30, 2024
Merged

Some FileDescriptor/FileDescription refactorings #3770

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d8aefd5
Make field private. It is not used outside the module and it should n…
oli-obk Jul 29, 2024
250b809
Split out actual `FileDescriptor` creation
oli-obk Jul 29, 2024
eb6589d
Rename `FileDescriptor` to `FileDescriptionRef`
oli-obk Jul 29, 2024
1ecd186
Rename all `file_descriptor` variables to `file_description` to match…
oli-obk Jul 29, 2024
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30 changes: 17 additions & 13 deletions src/shims/unix/fd.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -189,9 +189,13 @@ impl FileDescription for NullOutput {
}

#[derive(Clone, Debug)]
pub struct FileDescriptor(Rc<RefCell<Box<dyn FileDescription>>>);
pub struct FileDescriptionRef(Rc<RefCell<Box<dyn FileDescription>>>);

impl FileDescriptionRef {
fn new(fd: impl FileDescription) -> Self {
FileDescriptionRef(Rc::new(RefCell::new(Box::new(fd))))
}

impl FileDescriptor {
pub fn borrow(&self) -> Ref<'_, dyn FileDescription> {
Ref::map(self.0.borrow(), |fd| fd.as_ref())
}
Expand All @@ -213,7 +217,7 @@ impl FileDescriptor {
/// The file descriptor table
#[derive(Debug)]
pub struct FdTable {
pub fds: BTreeMap<i32, FileDescriptor>,
fds: BTreeMap<i32, FileDescriptionRef>,
}

impl VisitProvenance for FdTable {
Expand All @@ -239,14 +243,14 @@ impl FdTable {
fds
}

/// Insert a file descriptor to the FdTable.
pub fn insert_fd<T: FileDescription>(&mut self, fd: T) -> i32 {
let file_handle = FileDescriptor(Rc::new(RefCell::new(Box::new(fd))));
/// Insert a new file description to the FdTable.
pub fn insert_fd(&mut self, fd: impl FileDescription) -> i32 {
let file_handle = FileDescriptionRef::new(fd);
self.insert_fd_with_min_fd(file_handle, 0)
}

/// Insert a new FD that is at least `min_fd`.
pub fn insert_fd_with_min_fd(&mut self, file_handle: FileDescriptor, min_fd: i32) -> i32 {
fn insert_fd_with_min_fd(&mut self, file_handle: FileDescriptionRef, min_fd: i32) -> i32 {
// Find the lowest unused FD, starting from min_fd. If the first such unused FD is in
// between used FDs, the find_map combinator will return it. If the first such unused FD
// is after all other used FDs, the find_map combinator will return None, and we will use
Expand Down Expand Up @@ -282,12 +286,12 @@ impl FdTable {
Some(fd.borrow_mut())
}

pub fn dup(&self, fd: i32) -> Option<FileDescriptor> {
pub fn dup(&self, fd: i32) -> Option<FileDescriptionRef> {
let fd = self.fds.get(&fd)?;
Some(fd.clone())
}

pub fn remove(&mut self, fd: i32) -> Option<FileDescriptor> {
pub fn remove(&mut self, fd: i32) -> Option<FileDescriptionRef> {
self.fds.remove(&fd)
}

Expand Down Expand Up @@ -316,9 +320,9 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
if new_fd != old_fd {
// Close new_fd if it is previously opened.
// If old_fd and new_fd point to the same description, then `dup_fd` ensures we keep the underlying file description alive.
if let Some(file_descriptor) = this.machine.fds.fds.insert(new_fd, dup_fd) {
if let Some(file_description) = this.machine.fds.fds.insert(new_fd, dup_fd) {
// Ignore close error (not interpreter's) according to dup2() doc.
file_descriptor.close(this.machine.communicate())?.ok();
file_description.close(this.machine.communicate())?.ok();
}
}
Ok(new_fd)
Expand Down Expand Up @@ -385,10 +389,10 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {

let fd = this.read_scalar(fd_op)?.to_i32()?;

let Some(file_descriptor) = this.machine.fds.remove(fd) else {
let Some(file_description) = this.machine.fds.remove(fd) else {
return Ok(Scalar::from_i32(this.fd_not_found()?));
};
let result = file_descriptor.close(this.machine.communicate())?;
let result = file_description.close(this.machine.communicate())?;
// return `0` if close is successful
let result = result.map(|()| 0i32);
Ok(Scalar::from_i32(this.try_unwrap_io_result(result)?))
Expand Down
40 changes: 20 additions & 20 deletions src/shims/unix/fs.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -483,13 +483,13 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {

let communicate = this.machine.communicate();

let Some(mut file_descriptor) = this.machine.fds.get_mut(fd) else {
let Some(mut file_description) = this.machine.fds.get_mut(fd) else {
return Ok(Scalar::from_i64(this.fd_not_found()?));
};
let result = file_descriptor
let result = file_description
.seek(communicate, seek_from)?
.map(|offset| i64::try_from(offset).unwrap());
drop(file_descriptor);
drop(file_description);

let result = this.try_unwrap_io_result(result)?;
Ok(Scalar::from_i64(result))
Expand Down Expand Up @@ -1176,30 +1176,30 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
return Ok(Scalar::from_i32(this.fd_not_found()?));
}

let Some(file_descriptor) = this.machine.fds.get(fd) else {
let Some(file_description) = this.machine.fds.get(fd) else {
return Ok(Scalar::from_i32(this.fd_not_found()?));
};

// FIXME: Support ftruncate64 for all FDs
let FileHandle { file, writable } =
file_descriptor.downcast_ref::<FileHandle>().ok_or_else(|| {
file_description.downcast_ref::<FileHandle>().ok_or_else(|| {
err_unsup_format!("`ftruncate64` is only supported on file-backed file descriptors")
})?;

if *writable {
if let Ok(length) = length.try_into() {
let result = file.set_len(length);
drop(file_descriptor);
drop(file_description);
let result = this.try_unwrap_io_result(result.map(|_| 0i32))?;
Ok(Scalar::from_i32(result))
} else {
drop(file_descriptor);
drop(file_description);
let einval = this.eval_libc("EINVAL");
this.set_last_error(einval)?;
Ok(Scalar::from_i32(-1))
}
} else {
drop(file_descriptor);
drop(file_description);
// The file is not writable
let einval = this.eval_libc("EINVAL");
this.set_last_error(einval)?;
Expand Down Expand Up @@ -1229,16 +1229,16 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {

fn ffullsync_fd(&mut self, fd: i32) -> InterpResult<'tcx, i32> {
let this = self.eval_context_mut();
let Some(file_descriptor) = this.machine.fds.get(fd) else {
let Some(file_description) = this.machine.fds.get(fd) else {
return Ok(this.fd_not_found()?);
};
// Only regular files support synchronization.
let FileHandle { file, writable } =
file_descriptor.downcast_ref::<FileHandle>().ok_or_else(|| {
file_description.downcast_ref::<FileHandle>().ok_or_else(|| {
err_unsup_format!("`fsync` is only supported on file-backed file descriptors")
})?;
let io_result = maybe_sync_file(file, *writable, File::sync_all);
drop(file_descriptor);
drop(file_description);
this.try_unwrap_io_result(io_result)
}

Expand All @@ -1254,16 +1254,16 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
return this.fd_not_found();
}

let Some(file_descriptor) = this.machine.fds.get(fd) else {
let Some(file_description) = this.machine.fds.get(fd) else {
return Ok(this.fd_not_found()?);
};
// Only regular files support synchronization.
let FileHandle { file, writable } =
file_descriptor.downcast_ref::<FileHandle>().ok_or_else(|| {
file_description.downcast_ref::<FileHandle>().ok_or_else(|| {
err_unsup_format!("`fdatasync` is only supported on file-backed file descriptors")
})?;
let io_result = maybe_sync_file(file, *writable, File::sync_data);
drop(file_descriptor);
drop(file_description);
this.try_unwrap_io_result(io_result)
}

Expand Down Expand Up @@ -1302,18 +1302,18 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
return Ok(Scalar::from_i32(this.fd_not_found()?));
}

let Some(file_descriptor) = this.machine.fds.get(fd) else {
let Some(file_description) = this.machine.fds.get(fd) else {
return Ok(Scalar::from_i32(this.fd_not_found()?));
};
// Only regular files support synchronization.
let FileHandle { file, writable } =
file_descriptor.downcast_ref::<FileHandle>().ok_or_else(|| {
file_description.downcast_ref::<FileHandle>().ok_or_else(|| {
err_unsup_format!(
"`sync_data_range` is only supported on file-backed file descriptors"
)
})?;
let io_result = maybe_sync_file(file, *writable, File::sync_data);
drop(file_descriptor);
drop(file_description);
Ok(Scalar::from_i32(this.try_unwrap_io_result(io_result)?))
}

Expand Down Expand Up @@ -1609,11 +1609,11 @@ impl FileMetadata {
ecx: &mut MiriInterpCx<'tcx>,
fd: i32,
) -> InterpResult<'tcx, Option<FileMetadata>> {
let Some(file_descriptor) = ecx.machine.fds.get(fd) else {
let Some(file_description) = ecx.machine.fds.get(fd) else {
return ecx.fd_not_found().map(|_: i32| None);
};

let file = &file_descriptor
let file = &file_description
.downcast_ref::<FileHandle>()
.ok_or_else(|| {
err_unsup_format!(
Expand All @@ -1623,7 +1623,7 @@ impl FileMetadata {
.file;

let metadata = file.metadata();
drop(file_descriptor);
drop(file_description);
FileMetadata::from_meta(ecx, metadata)
}

Expand Down