Merge pull request #895 from tarka/ls-uname-group

Add username and groupname lookup to `ls`

src/ls/ls.rs

@@ -16,12 +16,16 @@ use pretty_bytes::converter::convert;
 #[macro_use]
 extern crate uucore;
 
+extern crate libc;
+use self::libc::c_char;
+
 use getopts::Options;
 use std::fs;
 use std::fs::{ReadDir, DirEntry, FileType, Metadata};
-use std::ffi::{OsString};
+use std::ffi::{OsString,CStr};
 use std::path::Path;
 use std::io::Write;
+use std::ptr;
 
 #[derive(Copy, Clone, PartialEq)]
 enum Mode {
@@ -143,15 +147,62 @@ fn display_dir_entry(entry: DirEntry, options: &getopts::Matches) {
         Ok(md) => md
     };
 
-    println!(" {}{} {} somebody somegroup {: >9} {}",
+    println!(" {}{} {} {} {} {: >9} {}",
              display_file_type(entry.file_type()),
              display_permissions(&md),
              display_symlink_count(&md),
+             display_uname(&md),
+             display_group(&md),
              display_file_size(&md, options),
              display_file_name(entry.file_name())
             );
 }
 
+fn cstr2string(cstr: *const c_char) -> String {
+    unsafe { String::from_utf8_lossy(CStr::from_ptr(cstr).to_bytes()).to_string() }
+}
+
+// Currently getpwuid is `linux` target only. If it's broken out into
+// a posix-compliant attribute this can be updated...
+#[cfg(target_family = "linux")]
+use uucore::c_types::{getpwuid, getgrgid};
+
+#[cfg(target_family = "linux")]
+fn display_uname(metadata: &Metadata) -> String {
+    use std::os::unix::fs::MetadataExt;
+
+    let pw = unsafe { getpwuid(metadata.uid()) };
+    if !pw.is_null() {
+        cstr2string(unsafe { ptr::read(pw).pw_name })
+    } else {
+        metadata.uid().to_string()
+    }
+}
+
+#[cfg(target_family = "linux")]
+fn display_group(metadata: &Metadata) -> String {
+    use std::os::unix::fs::MetadataExt;
+
+    let ent = unsafe { getgrgid(metadata.gid()) };
+    if !ent.is_null() {
+        cstr2string(unsafe { ptr::read(ent).gr_name })
+    } else {
+        metadata.gid().to_string()
+    }
+}
+
+#[cfg(not(target_family = "linux"))]
+#[allow(unused_variables)]
+fn display_uname(metadata: &Metadata) -> String {
+    "somebody".to_string()
+}
+
+#[cfg(not(target_family = "linux"))]
+#[allow(unused_variables)]
+fn display_group(metadata: &Metadata) -> String {
+    "somegroup".to_string()
+}
+
 fn display_file_size(metadata: &Metadata, options: &getopts::Matches) -> String {
     if options.opt_present("human-readable") {
         convert(metadata.len() as f64)
@@ -193,7 +244,6 @@ fn display_symlink_count(metadata: &Metadata) -> String {
 #[cfg(target_family = "unix")]
 fn display_symlink_count(metadata: &Metadata) -> String {
     use std::os::unix::fs::MetadataExt;
-    
     metadata.nlink().to_string()
 }