Id first and ugly phase

Makefile

@@ -27,6 +27,7 @@ PROGS       := \
   whoami \
   yes \
   tty \
+  id \
 
 BUILD       ?= $(PROGS)
 

id/id.rs

@@ -0,0 +1,135 @@
+#[crate_id(name="id", version="1.0.0", author="Alan Andrade")];
+
+/*
+ * This file is part of the uutils coreutils package.
+ *
+ * (c) Boden Garman <[email protected]>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ *
+ * XXX: Add synced with file [here]
+ */
+
+use std::{libc,ptr,vec};
+use std::str::raw;
+
+// XXX: Sync with whoami.rs
+
+struct c_passwd {
+    pw_name: *libc::c_char,  /* user name */
+    pw_uid:   libc::c_int,   /* user uid */
+    pw_gid:   libc::c_int    /* user gid */
+}
+
+struct c_group {
+    gr_name: *libc::c_char /* group name */
+}
+
+extern {
+    // Effective user id
+    fn geteuid () -> libc::c_int;
+    // Real user id
+    fn getuid () -> libc::c_int;
+
+    // Effective group id
+    fn getegid () -> libc::c_int;
+    // Real group id
+    fn getgid () -> libc::c_int;
+
+    fn getpwuid(uid: libc::c_int) -> *c_passwd;
+    fn getgrgid(gid: libc::c_int) -> *c_group;
+
+    //fn getgrent() -> *c_group;
+    //fn endgrent();
+}
+
+fn main () {
+    let euid = unsafe { geteuid () };
+    let ruid = unsafe { getuid () };
+    let egid = unsafe { getegid () };
+    let rgid = unsafe { getgid () };
+
+    print_full_info(ruid, rgid, euid, egid);
+}
+
+fn print_full_info (ruid: libc::c_int,
+                    rgid: libc::c_int,
+                    euid: libc::c_int,
+                    egid: libc::c_int) {
+
+    print!("uid={:d}", ruid);
+    // XXX: Read from pointer straight away ?
+    //
+    // How'd be NULL check ?
+    let pwd = unsafe { ptr::read_ptr(getpwuid(ruid)) };
+    //if pwd {
+        let username = unsafe {
+            raw::from_c_str(pwd.pw_name)
+        };
+
+        print!("({:s})", username);
+    //}
+
+
+    print!(" gid={:d}", rgid);
+    let grp = unsafe { getgrgid(rgid) };
+    if ptr::is_not_null(grp) {
+        unsafe {
+            print!("({:s})", raw::from_c_str(ptr::read_ptr(grp).gr_name));
+        }
+    }
+
+
+    if euid != ruid {
+        print!(" euid={:d}", euid);
+        let pwd = unsafe { getpwuid(euid) };
+        if ptr::is_not_null(pwd) {
+            let username = unsafe {
+                raw::from_c_str(ptr::read_ptr(pwd).pw_name)
+            };
+            print!("({:s})", username);
+        }
+    }
+
+
+    if egid != rgid {
+        print!(" egid={:d}", egid);
+        let grp = unsafe { getgrgid(rgid) };
+        if ptr::is_not_null(grp) {
+            let groupname = unsafe {
+                raw::from_c_str(ptr::read_ptr(grp).gr_name)
+            };
+            print!("({:s})", groupname)
+        }
+    }
+
+    let mut groups = std::vec::with_capacity(69);
+    unsafe { groups.set_len(69); }
+    let n_groups = unsafe { libc::getgroups(13, groups.as_mut_ptr()) };
+
+    if n_groups < 0 {
+        println!("{:?}", std::os::errno());
+    }
+
+    if n_groups > 0 {
+        print!(" groups=");
+
+        for i in range(0, n_groups) {
+            if i > 0 {
+                print!(",")
+            }
+            print!("{:u}", groups[i]);
+            let group = unsafe { getgrgid(groups[i] as i32) };
+            if ptr::is_not_null(group) {
+                let name = unsafe {
+                    raw::from_c_str(ptr::read_ptr(group).gr_name)
+                };
+                print!("({:s})", name);
+            }
+        }
+
+        println!("");
+    }
+
+}