tools.rs: new scandir() helper

src/tools.rs

@@ -15,6 +15,7 @@ use std::io::Read;
 use std::io::ErrorKind;
 use std::time::Duration;
 
+use std::os::unix::io::RawFd;
 use std::os::unix::io::AsRawFd;
 
 use serde_json::Value;
@@ -230,6 +231,7 @@ pub fn file_chunker<C, R>(
     Ok(())
 }
 
+/// Returns the hosts node name (UTS node name)
 pub fn nodename() -> &'static str {
 
     lazy_static!{
@@ -313,3 +315,43 @@ pub fn complete_file_name(arg: &str) -> Vec<String> {
 
     result
 }
+
+/// Scan directory for matching file names.
+///
+/// Scan through all directory entries and call `callback()` function
+/// if the entry name matches the regular expression. This function
+/// used unix `openat()`, so you can pass absolute or relative file
+/// names. This function simply skips non-UTF8 encoded names.
+pub fn scandir<P, F>(
+    dirfd: RawFd,
+    path: P,
+    regex: &regex::Regex,
+    callback: F
+) -> Result<(), Error>
+    where F: Fn(RawFd, &str, nix::dir::Type) -> Result<(), Error>,
+          P: AsRef<Path>
+{
+    use nix::fcntl::OFlag;
+    use nix::sys::stat::Mode;
+
+    let mut subdir = nix::dir::Dir::openat(dirfd, path.as_ref(), OFlag::O_RDONLY, Mode::empty())?;
+    let subdir_fd = subdir.as_raw_fd();
+
+    for entry in subdir.iter() {
+        let entry = entry?;
+        let file_type = match entry.file_type() {
+            Some(file_type) => file_type,
+            None => bail!("unable to detect file type"),
+        };
+        let filename = entry.file_name();
+        let filename_str = match filename.to_str() {
+            Ok(name) => name,
+            Err(_) => continue /* ignore non utf8 entries*/,
+        };
+
+        if !regex.is_match(filename_str) { continue; }
+
+        (callback)(subdir_fd, filename_str, file_type)?;
+    }
+    Ok(())
+}