Skip to content

Commit

Permalink
Auto merge of #116683 - ChrisDenton:exists, r=Mark-Simulacrum
Browse files Browse the repository at this point in the history
Make `try_exists` return `Ok(true)` for Windows Unix Sockets

This is a follow up to #109106 but for[ `fs::try_exists`](https://doc.rust-lang.org/std/fs/fn.try_exists.html), which doesn't need to get the metadata of a file (which can fail even if a file exists).

`fs::try_exists` currently fails on Windows if encountering a Unix Domain Socket (UDS). This PR fixes it by checking for an error code that's returned when there's a failure to use a reparse point.

## Reparse points

A reparse point is a way to invoke a filesystem filter on a file instead of the file being opened normally. This is used to implement symbolic links (by redirecting to a different path) but also to implement other types of special files such as Unix domain sockets. If the reparse point is not a link type then opening it with `CreateFileW` may fail with `ERROR_CANT_ACCESS_FILE` because the filesystem filter does not implement that operation. This differs from resolving links which may fail with errors such as `ERROR_FILE_NOT_FOUND` or `ERROR_CANT_RESOLVE_FILENAME`.

So `ERROR_CANT_ACCESS_FILE` means that the file exists but that we can't open it normally. Still, the file does exist on the filesystem so `try_exists` should report that as `Ok(true)`.

r? libs
  • Loading branch information
bors committed Oct 15, 2023
2 parents dda7d4c + 2f5dea0 commit ff5664d
Show file tree
Hide file tree
Showing 4 changed files with 56 additions and 0 deletions.
35 changes: 35 additions & 0 deletions library/std/src/fs/tests.rs
Original file line number Diff line number Diff line change
Expand Up @@ -1707,3 +1707,38 @@ fn test_file_times() {
assert_eq!(metadata.created().unwrap(), created);
}
}

#[test]
#[cfg(windows)]
fn windows_unix_socket_exists() {
use crate::sys::{c, net};
use crate::{mem, ptr};

let tmp = tmpdir();
let socket_path = tmp.join("socket");

// std doesn't current support Unix sockets on Windows so manually create one here.
net::init();
unsafe {
let socket = c::WSASocketW(
c::AF_UNIX as i32,
c::SOCK_STREAM,
0,
ptr::null_mut(),
0,
c::WSA_FLAG_OVERLAPPED | c::WSA_FLAG_NO_HANDLE_INHERIT,
);
assert_ne!(socket, c::INVALID_SOCKET);
let mut addr = c::SOCKADDR_UN { sun_family: c::AF_UNIX, sun_path: mem::zeroed() };
let bytes = socket_path.as_os_str().as_encoded_bytes();
addr.sun_path[..bytes.len()].copy_from_slice(bytes);
let len = mem::size_of_val(&addr) as i32;
let result = c::bind(socket, ptr::addr_of!(addr).cast::<c::SOCKADDR>(), len);
c::closesocket(socket);
assert_eq!(result, 0);
}
// Make sure all ways of testing a file exist work for a Unix socket.
assert_eq!(socket_path.exists(), true);
assert_eq!(socket_path.try_exists().unwrap(), true);
assert_eq!(socket_path.metadata().is_ok(), true);
}
2 changes: 2 additions & 0 deletions library/std/src/sys/windows/c/windows_sys.lst
Original file line number Diff line number Diff line change
Expand Up @@ -1964,6 +1964,7 @@ Windows.Win32.Networking.WinSock.ADDRESS_FAMILY
Windows.Win32.Networking.WinSock.ADDRINFOA
Windows.Win32.Networking.WinSock.AF_INET
Windows.Win32.Networking.WinSock.AF_INET6
Windows.Win32.Networking.WinSock.AF_UNIX
Windows.Win32.Networking.WinSock.AF_UNSPEC
Windows.Win32.Networking.WinSock.bind
Windows.Win32.Networking.WinSock.closesocket
Expand Down Expand Up @@ -2058,6 +2059,7 @@ Windows.Win32.Networking.WinSock.SOCK_RDM
Windows.Win32.Networking.WinSock.SOCK_SEQPACKET
Windows.Win32.Networking.WinSock.SOCK_STREAM
Windows.Win32.Networking.WinSock.SOCKADDR
Windows.Win32.Networking.WinSock.SOCKADDR_UN
Windows.Win32.Networking.WinSock.SOCKET
Windows.Win32.Networking.WinSock.SOCKET_ERROR
Windows.Win32.Networking.WinSock.SOL_SOCKET
Expand Down
12 changes: 12 additions & 0 deletions library/std/src/sys/windows/c/windows_sys.rs
Original file line number Diff line number Diff line change
Expand Up @@ -847,6 +847,7 @@ impl ::core::clone::Clone for ADDRINFOA {
}
pub const AF_INET: ADDRESS_FAMILY = 2u16;
pub const AF_INET6: ADDRESS_FAMILY = 23u16;
pub const AF_UNIX: u16 = 1u16;
pub const AF_UNSPEC: ADDRESS_FAMILY = 0u16;
pub const ALL_PROCESSOR_GROUPS: u32 = 65535u32;
#[repr(C)]
Expand Down Expand Up @@ -3813,6 +3814,17 @@ impl ::core::clone::Clone for SOCKADDR {
*self
}
}
#[repr(C)]
pub struct SOCKADDR_UN {
pub sun_family: ADDRESS_FAMILY,
pub sun_path: [u8; 108],
}
impl ::core::marker::Copy for SOCKADDR_UN {}
impl ::core::clone::Clone for SOCKADDR_UN {
fn clone(&self) -> Self {
*self
}
}
pub type SOCKET = usize;
pub const SOCKET_ERROR: i32 = -1i32;
pub const SOCK_DGRAM: WINSOCK_SOCKET_TYPE = 2i32;
Expand Down
7 changes: 7 additions & 0 deletions library/std/src/sys/windows/fs.rs
Original file line number Diff line number Diff line change
Expand Up @@ -1515,6 +1515,13 @@ pub fn try_exists(path: &Path) -> io::Result<bool> {
// as the file existing.
_ if e.raw_os_error() == Some(c::ERROR_SHARING_VIOLATION as i32) => Ok(true),

// `ERROR_CANT_ACCESS_FILE` means that a file exists but that the
// reparse point could not be handled by `CreateFile`.
// This can happen for special files such as:
// * Unix domain sockets which you need to `connect` to
// * App exec links which require using `CreateProcess`
_ if e.raw_os_error() == Some(c::ERROR_CANT_ACCESS_FILE as i32) => Ok(true),

// Other errors such as `ERROR_ACCESS_DENIED` may indicate that the
// file exists. However, these types of errors are usually more
// permanent so we report them here.
Expand Down

0 comments on commit ff5664d

Please sign in to comment.