sketchy path_open

crates/wasi-c2/src/dir.rs

@@ -1,15 +1,75 @@
 // this file is extremely wip
 #![allow(dead_code, unused_variables)]
+use crate::error::Error;
+use crate::file::{self, WasiFile};
+use std::ops::Deref;
 use std::path::PathBuf;
 
-pub trait WasiDir {}
+pub trait WasiDir {
+    fn open_file(
+        &self,
+        symlink_follow: bool,
+        path: &str,
+        oflags: file::OFlags,
+        fdflags: file::FdFlags,
+    ) -> Result<Box<dyn WasiFile>, Error>;
+
+    fn open_dir(
+        &self,
+        symlink_follow: bool,
+        path: &str,
+        create: bool,
+    ) -> Result<Box<dyn WasiDir>, Error>;
+}
 
 pub(crate) struct DirEntry {
-    pub(crate) flags: u32,
+    pub(crate) base_caps: DirCaps,
+    pub(crate) inheriting_caps: DirCaps,
     pub(crate) preopen_path: Option<PathBuf>, // precondition: PathBuf is valid unicode
     pub(crate) dir: Box<dyn WasiDir>,
 }
 
+impl DirEntry {
+    pub fn get_cap(&self, caps: DirCaps) -> Result<&dyn WasiDir, Error> {
+        if self.base_caps.contains(&caps) && self.inheriting_caps.contains(&caps) {
+            Ok(self.dir.deref())
+        } else {
+            Err(Error::DirNotCapable(caps))
+        }
+    }
+}
+
+#[derive(Debug, Clone, Copy)]
+pub struct DirCaps {
+    flags: u32,
+}
+
+impl DirCaps {
+    pub fn empty() -> Self {
+        DirCaps { flags: 0 }
+    }
+
+    /// Checks if `other` is a subset of those capabilties:
+    pub fn contains(&self, other: &Self) -> bool {
+        self.flags & other.flags == other.flags
+    }
+
+    pub const OPEN: Self = DirCaps { flags: 1 };
+    pub const READDIR: Self = DirCaps { flags: 2 };
+    pub const READLINK: Self = DirCaps { flags: 4 };
+    pub const RENAME_SOURCE: Self = DirCaps { flags: 8 };
+    pub const RENAME_TARGET: Self = DirCaps { flags: 16 };
+    pub const SYMLINK: Self = DirCaps { flags: 32 };
+    pub const REMOVE_DIRECTORY: Self = DirCaps { flags: 64 };
+    pub const UNLINK_FILE: Self = DirCaps { flags: 128 };
+}
+
+impl std::fmt::Display for DirCaps {
+    fn fmt(&self, _f: &mut std::fmt::Formatter) -> std::fmt::Result {
+        todo!()
+    }
+}
+
 pub trait TableDirExt {
     fn is_preopen(&self, fd: u32) -> bool;
 }