Support for macOS

[jabedude]

Add support for macOS arm64/x64 + FreeBSD (insofar as any code can be shared between platforms)

[qforce85]

The documentation over at docs.rs misleadingly suggests that ofiles supports macOS 64-bit, but it actually doesn't work, it only compiles.

The following test program takes a file path from the command-line and prints whether the file is open or not. On Linux, this works as expected: It either prints "is_open: true" or "is_open: false". On macOS 10.15, it always prints "is_open: false".

use std::io::Result;
use std::path::{Path, PathBuf};

fn main() {
	let arg = std::env::args().nth(1).unwrap();
	let path = PathBuf::from(arg);
	match is_open(path.as_path()) {
		Ok(pred) => println!("is_open: {:?}", pred),
		Err(_) => println!("is_open failed"),
	}
}

fn is_open(path: &Path) -> Result<bool> {
	if !path.is_file() {
		return Ok(false)
	}
	use std::io::{Error, ErrorKind};
	match ofiles::opath(path) {
		Ok(pids) => Ok(!pids.is_empty()),
		Err(e) => Err(Error::new(ErrorKind::Other, e.description())),
	}
}

[jabedude]

Hi @qforce85, I don't see any info on docs.rs or the crates.io page that claims or suggests that files works on macOS. Could you show me a screenshot of what you're referring to?

[qforce85]

Sure, see the red arrow in the attached screenshot.

[jabedude]

Interesting, looks like docs.rs will build for a few default targets documented here: https://docs.rs/about/metadata. Relevant snippet:

# Target to test build on, used as the default landing page (default: "x86_64-unknown-linux-gnu")
#
# Any target supported by rustup can be used.
default-target = "x86_64-unknown-linux-gnu"

# Targets to build (default: see below)
#
# Any target supported by rustup can be used.
#
# Default targets:
# - x86_64-unknown-linux-gnu
# - x86_64-apple-darwin
# - x86_64-pc-windows-msvc
# - i686-unknown-linux-gnu
# - i686-pc-windows-msvc
#
# Set this to `[]` to only build the default target.
#
# If `default-target` is unset, the first element of `targets` is treated as the default target.
# Otherwise, these `targets` are built in addition to the default target.
# If both `default-target` and `targets` are unset,
#   all tier-one targets will be built and `x86_64-unknown-linux-gnu` will be used as the default target.
targets = ["x86_64-apple-darwin", "x86_64-pc-windows-msvc"]

[joyanedel]

The problem actually comes from https://github.com/jabedude/ofiles/blob/master/src/lib.rs#L106
Function opath assumes macOS contains file descriptors in the same folder structure that linux systems but actually it does not.

Linux contains all file descriptors among other useful data under /proc (/proc/*/fd/*) directory. MacOS on the other hand contains it under /dev/fd (only available for the calling process).

I don't see any robust solution but the usage of lsof