EX-1932 handle softlinks for llapi queries (#2325)

* EX-1932 handle softlinks for llapi queries

When constructing an llapi instance from a random path
liblustreapi first resolves that path fully, including
symbolic links.  This causes a failure when trying to
get an llapi instance from a symbolic link that lives on
a lustre filesystem (ex /mnt/lustre/symbolic_link)

If the path passed into search_fsname is a link, use
the parent dir instead.

Signed-off-by: Ben Evans <beevans@whamcloud.com>

* Code review fixes

Signed-off-by: Ben Evans <beevans@whamcloud.com>

* Indent code correctly

Signed-off-by: Ben Evans <beevans@whamcloud.com>

* More review comments

Signed-off-by: Ben Evans <beevans@whamcloud.com>

liblustreapi/src/lib.rs

@@ -12,6 +12,7 @@ use std::{
  ffi::{CStr, CString},
  fmt, io,
  num::ParseIntError,
+ os::unix::ffi::OsStrExt,
  path::PathBuf,
  str::FromStr,
  sync::Arc,
@@ -305,7 +306,13 @@ impl Llapi {
  }
 
  pub fn search_fsname(&self, pathname: &str) -> Result<String, LiblustreError> {
- let fsc = CString::new(pathname.as_bytes())?;
+ let mut path = PathBuf::from(pathname);
+ let md = std::fs::symlink_metadata(&path)?;
+ if md.file_type().is_symlink() {
+ path.pop();
+ }
+
+ let fsc = CString::new(path.into_os_string().as_bytes())?;
  let mut fsname: Vec<u8> = vec![0; std::mem::size_of::<u8>() * MAXFSNAME + 1];
  let ptr = fsname.as_mut_ptr() as *mut libc::c_char;