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NetBSD: add sysctl backend for std::env::current_exe #46373

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Merged
merged 1 commit into from
Dec 2, 2017
Merged

NetBSD: add sysctl backend for std::env::current_exe #46373

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29 changes: 28 additions & 1 deletion src/libstd/sys/unix/os.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -223,7 +223,34 @@ pub fn current_exe() -> io::Result<PathBuf> {

#[cfg(target_os = "netbsd")]
pub fn current_exe() -> io::Result<PathBuf> {
::fs::read_link("/proc/curproc/exe")
fn sysctl() -> io::Result<PathBuf> {
unsafe {
let mib = [libc::CTL_KERN, libc::KERN_PROC_ARGS, -1, libc::KERN_PROC_PATHNAME];
let mut path_len: usize = 0;
cvt(libc::sysctl(mib.as_ptr(), mib.len() as ::libc::c_uint,
ptr::null_mut(), &mut path_len,
ptr::null(), 0))?;
if path_len <= 1 {
return Err(io::Error::new(io::ErrorKind::Other,
"KERN_PROC_PATHNAME sysctl returned zero-length string"))
}
let mut path: Vec<u8> = Vec::with_capacity(path_len);
cvt(libc::sysctl(mib.as_ptr(), mib.len() as ::libc::c_uint,
path.as_ptr() as *mut libc::c_void, &mut path_len,
ptr::null(), 0))?;
path.set_len(path_len - 1); // chop off NUL
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Do you need to check path_len == 0 just like the FreeBSD implementation above? Or is it possible to merge the implementations of the BSDs (only the mib differ as far as I can see).

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Possibly could even check for path_len <= 1 for additional safety. There are a few very subtle differences between the FreeBSD & DragonFly block and what I implemented, but I imagine they could be merged if thought best. While they are nearly identical, I have this purist view that as there is no shared lineage in the kernel-side implementation of these sysctls, they may as well stay seperate here.

Ok(PathBuf::from(OsString::from_vec(path)))
}
}
fn procfs() -> io::Result<PathBuf> {
let curproc_exe = path::Path::new("/proc/curproc/exe");
if curproc_exe.is_file() {
return ::fs::read_link(curproc_exe);
}
Err(io::Error::new(io::ErrorKind::Other,
"/proc/curproc/exe doesn't point to regular file."))
}
sysctl().or_else(|_| procfs())
}

#[cfg(any(target_os = "bitrig", target_os = "openbsd"))]
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