Add example CLI app for printing file ACL

examples/printacl.rs

@@ -0,0 +1,64 @@
+//! Example CLI app to read and print ACL of a file.
+//!
+//! Run with command: `cargo run --example printacl /some/path`
+
+use posix_acl::Qualifier::*;
+use posix_acl::{ACLEntry, PosixACL, ACL_EXECUTE, ACL_READ, ACL_WRITE};
+use std::env::args_os;
+use std::path::Path;
+use std::process::exit;
+
+fn print_acl(acl: PosixACL) {
+    let entries = acl.entries();
+    if entries.is_empty() {
+        // Happens
+        println!("    (no entries)")
+    }
+    for entry in entries {
+        let ACLEntry { qual, perm } = entry;
+        println!(
+            "    {}:{}{}{}",
+            match qual {
+                Undefined => "invalid:".into(),
+                UserObj => "user:".into(),
+                GroupObj => "group:".into(),
+                Other => "other:".into(),
+                User(uid) => format!("user:{}", uid),
+                Group(gid) => format!("group:{}", gid),
+                Mask => "mask:".into(),
+            },
+            if perm & ACL_READ != 0 { "r" } else { "-" },
+            if perm & ACL_WRITE != 0 { "w" } else { "-" },
+            if perm & ACL_EXECUTE != 0 { "x" } else { "-" },
+        )
+    }
+}
+
+fn main() {
+    let args = args_os();
+    if args.len() <= 1 {
+        println!("Usage: printacl [FILE ...]");
+        exit(1);
+    }
+
+    for filename in args.skip(1) {
+        let path = Path::new(&filename);
+        match PosixACL::read_acl(path) {
+            Ok(acl) => {
+                println!("{} ACL:", path.display());
+                print_acl(acl)
+            }
+            Err(e) => eprintln!("{}: {}", path.display(), e),
+        }
+        if path.is_dir() {
+            match PosixACL::read_default_acl(path) {
+                Ok(acl) => {
+                    println!("{} DEFAULT:", path.display());
+                    print_acl(acl)
+                }
+                Err(e) => eprintln!("{}: {}", path.display(), e),
+            }
+        }
+        println!();
+    }
+}