cap_primitives/rustix/fs/
read_dir_inner.rs

1use crate::fs::{
2    open_dir_for_reading, open_dir_for_reading_unchecked, open_entry_impl, read_dir_unchecked,
3    remove_dir_unchecked, remove_file_unchecked, stat_unchecked, DirEntryInner, FollowSymlinks,
4    Metadata, OpenOptions, ReadDir,
5};
6use io_extras::os::rustix::{AsRawFd, FromRawFd, RawFd};
7use io_lifetimes::AsFd;
8use rustix::fd::OwnedFd;
9use rustix::fs::Dir;
10use std::ffi::OsStr;
11use std::mem::ManuallyDrop;
12#[cfg(unix)]
13use std::os::unix::ffi::OsStrExt;
14#[cfg(target_os = "wasi")]
15use std::os::wasi::ffi::OsStrExt;
16use std::path::{Component, Path};
17use std::sync::{Arc, Mutex};
18use std::{fmt, fs, io};
19
20pub(crate) struct ReadDirInner {
21    raw_fd: RawFd,
22
23    // `Dir` doesn't implement `AsFd`, because libc `fdopendir` has UB if the
24    // file descriptor is used in almost any way, so we hold a separate
25    // `OwnedFd` that we can do `as_fd()` on.
26    rustix: Arc<Mutex<(Dir, OwnedFd)>>,
27}
28
29impl ReadDirInner {
30    pub(crate) fn new(start: &fs::File, path: &Path, follow: FollowSymlinks) -> io::Result<Self> {
31        let fd = open_dir_for_reading(start, path, follow)?;
32        let dir = Dir::read_from(fd.as_fd())?;
33        Ok(Self {
34            raw_fd: fd.as_fd().as_raw_fd(),
35            rustix: Arc::new(Mutex::new((dir, OwnedFd::from(fd)))),
36        })
37    }
38
39    pub(crate) fn read_base_dir(start: &fs::File) -> io::Result<Self> {
40        // Open ".", to obtain a new independent file descriptor. Don't use
41        // `dup` since in that case the resulting file descriptor would share
42        // a current position with the original, and `read_dir` calls after
43        // the first `read_dir` call wouldn't start from the beginning.
44        let fd =
45            open_dir_for_reading_unchecked(start, Component::CurDir.as_ref(), FollowSymlinks::No)?;
46        let dir = Dir::read_from(fd.as_fd())?;
47        Ok(Self {
48            raw_fd: fd.as_fd().as_raw_fd(),
49            rustix: Arc::new(Mutex::new((dir, fd.into()))),
50        })
51    }
52
53    pub(crate) fn new_unchecked(
54        start: &fs::File,
55        path: &Path,
56        follow: FollowSymlinks,
57    ) -> io::Result<Self> {
58        let fd = open_dir_for_reading_unchecked(start, path, follow)?;
59        let dir = Dir::read_from(fd.as_fd())?;
60        Ok(Self {
61            raw_fd: fd.as_fd().as_raw_fd(),
62            rustix: Arc::new(Mutex::new((dir, fd.into()))),
63        })
64    }
65
66    pub(super) fn open(&self, file_name: &OsStr, options: &OpenOptions) -> io::Result<fs::File> {
67        open_entry_impl(&self.as_file_view(), file_name, options)
68    }
69
70    pub(super) fn metadata(&self, file_name: &OsStr) -> io::Result<Metadata> {
71        stat_unchecked(&self.as_file_view(), file_name.as_ref(), FollowSymlinks::No)
72    }
73
74    pub(super) fn remove_file(&self, file_name: &OsStr) -> io::Result<()> {
75        remove_file_unchecked(&self.as_file_view(), file_name.as_ref())
76    }
77
78    pub(super) fn remove_dir(&self, file_name: &OsStr) -> io::Result<()> {
79        remove_dir_unchecked(&self.as_file_view(), file_name.as_ref())
80    }
81
82    pub(super) fn self_metadata(&self) -> io::Result<Metadata> {
83        Metadata::from_file(&self.as_file_view())
84    }
85
86    pub(super) fn read_dir(
87        &self,
88        file_name: &OsStr,
89        follow: FollowSymlinks,
90    ) -> io::Result<ReadDir> {
91        read_dir_unchecked(&self.as_file_view(), file_name.as_ref(), follow)
92    }
93
94    #[allow(unsafe_code)]
95    fn as_file_view(&self) -> ManuallyDrop<fs::File> {
96        // Safety: `self.rustix` owns the file descriptor. We just hold a
97        // copy outside so that we can read it without taking a lock.
98        ManuallyDrop::new(unsafe { fs::File::from_raw_fd(self.raw_fd) })
99    }
100}
101
102impl Iterator for ReadDirInner {
103    type Item = io::Result<DirEntryInner>;
104
105    fn next(&mut self) -> Option<Self::Item> {
106        loop {
107            let entry = self.rustix.lock().unwrap().0.read()?;
108            let entry = match entry {
109                Ok(entry) => entry,
110                Err(e) => return Some(Err(e.into())),
111            };
112            let file_name = entry.file_name().to_bytes();
113            if file_name != Component::CurDir.as_os_str().as_bytes()
114                && file_name != Component::ParentDir.as_os_str().as_bytes()
115            {
116                let clone = Arc::clone(&self.rustix);
117                return Some(Ok(DirEntryInner {
118                    rustix: entry,
119                    read_dir: Self {
120                        raw_fd: self.raw_fd,
121                        rustix: clone,
122                    },
123                }));
124            }
125        }
126    }
127}
128
129impl fmt::Debug for ReadDirInner {
130    // Like libstd's version, but doesn't print the path.
131    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
132        let mut b = f.debug_struct("ReadDir");
133        b.field("raw_fd", &self.raw_fd);
134        b.finish()
135    }
136}
cap_primitives/rustix/fs/read_dir_inner.rs

cap_primitives/rustix/fs/
read_dir_inner.rs
