diff --git a/src/pinky/pinky.rs b/src/pinky/pinky.rs
index cec6022a3..e441cd33e 100644
--- a/src/pinky/pinky.rs
+++ b/src/pinky/pinky.rs
@@ -373,8 +373,6 @@ impl Pinky {
             }
         }
 
-        // WARNING: Because of the definition of `struct utmp`,
-        // pinky cannot get the correct value of utmp.ut_tv
         print!(" {}", time_string(&ut));
 
         if self.include_where && ut.ut_host[0] != 0 {
diff --git a/src/pinky/utmp.rs b/src/pinky/utmp.rs
index 93f32bfff..413994a68 100644
--- a/src/pinky/utmp.rs
+++ b/src/pinky/utmp.rs
@@ -6,37 +6,30 @@
 // file that was distributed with this source code.
 //
 extern crate uucore;
-use uucore::utmpx::c_utmp;
+use uucore::utmpx;
 
 use std::ptr;
 
-#[cfg(unix)]
-extern "C" {
-    fn getutxent() -> *const c_utmp;
-    fn setutxent();
-    fn endutxent();
-}
-
 pub struct UtmpIter;
 
 impl UtmpIter {
     fn new() -> Self {
         unsafe {
-            setutxent();
+            utmpx::setutxent();
         }
         UtmpIter
     }
 }
 
 impl Iterator for UtmpIter {
-    type Item = c_utmp;
+    type Item = utmpx::c_utmp;
 
     fn next(&mut self) -> Option<Self::Item> {
         unsafe {
-            let line = getutxent();
+            let line = utmpx::getutxent();
 
             if line.is_null() {
-                endutxent();
+                utmpx::endutxent();
                 return None;
             }
 
diff --git a/src/uptime/Cargo.toml b/src/uptime/Cargo.toml
index 977d03bf3..78fd30902 100644
--- a/src/uptime/Cargo.toml
+++ b/src/uptime/Cargo.toml
@@ -9,7 +9,7 @@ path = "uptime.rs"
 
 [dependencies]
 getopts = "*"
-libc = "*"
+libc = { git = "https://github.com/rust-lang/libc.git" }
 time = "*"
 uucore = { path="../uucore" }
 
diff --git a/src/uptime/uptime.rs b/src/uptime/uptime.rs
index 71e9f9cff..942fee683 100644
--- a/src/uptime/uptime.rs
+++ b/src/uptime/uptime.rs
@@ -19,7 +19,7 @@ extern crate time as rtime;
 extern crate uucore;
 
 use getopts::Options;
-use libc::{time_t, c_double, c_int, c_char};
+use libc::{time_t, c_double};
 use std::ffi::CString;
 use std::fs::File;
 use std::io::{Read, Write};
@@ -31,27 +31,13 @@ static NAME: &'static str = "uptime";
 static VERSION: &'static str = env!("CARGO_PKG_VERSION");
 
 #[cfg(unix)]
-extern {
-    fn getloadavg(loadavg: *mut c_double, nelem: c_int) -> c_int;
-
-    fn getutxent() -> *const c_utmp;
-    fn setutxent();
-    fn endutxent();
-
-    #[cfg(any(target_os = "macos", target_os = "linux"))]
-    fn utmpxname(file: *const c_char) -> c_int;
-}
+use libc::getloadavg;
 
 #[cfg(windows)]
 extern {
     fn GetTickCount() -> libc::uint32_t;
 }
 
-#[cfg(target_os = "freebsd")]
-unsafe extern fn utmpxname(_file: *const c_char) -> c_int {
-    0
-}
-
 pub fn uumain(args: Vec<String>) -> i32 {
     let mut opts = Options::new();
 
@@ -128,7 +114,7 @@ fn process_utmpx() -> (Option<time_t>, usize) {
                 BOOT_TIME => {
                     let t = (*line).ut_tv;
                     if t.tv_sec > 0 {
-                        boot_time = Some(t.tv_sec);
+                        boot_time = Some(t.tv_sec as time_t);
                     }
                 },
                 _ => continue
diff --git a/src/users/users.rs b/src/users/users.rs
index 86081d76a..d4394de47 100644
--- a/src/users/users.rs
+++ b/src/users/users.rs
@@ -26,25 +26,6 @@ use std::mem;
 use std::ptr;
 use uucore::utmpx::*;
 
-extern {
-    fn getutxent() -> *const c_utmp;
-    fn getutxid(ut: *const c_utmp) -> *const c_utmp;
-    fn getutxline(ut: *const c_utmp) -> *const c_utmp;
-
-    fn pututxline(ut: *const c_utmp) -> *const c_utmp;
-
-    fn setutxent();
-    fn endutxent();
-
-    #[cfg(any(target_os = "macos", target_os = "linux"))]
-    fn utmpxname(file: *const libc::c_char) -> libc::c_int;
-}
-
-#[cfg(target_os = "freebsd")]
-unsafe extern fn utmpxname(_file: *const libc::c_char) -> libc::c_int {
-    0
-}
-
 static NAME: &'static str = "users";
 static VERSION: &'static str = env!("CARGO_PKG_VERSION");
 
diff --git a/src/uucore/utmpx.rs b/src/uucore/utmpx.rs
index 8b6bc742e..c249e2a94 100644
--- a/src/uucore/utmpx.rs
+++ b/src/uucore/utmpx.rs
@@ -2,7 +2,26 @@
 
 extern crate libc;
 
-pub use self::utmpx::{UT_NAMESIZE,UT_LINESIZE,DEFAULT_FILE,USER_PROCESS,BOOT_TIME,c_utmp};
+pub use self::utmpx::{UT_NAMESIZE, UT_LINESIZE, DEFAULT_FILE, USER_PROCESS, BOOT_TIME};
+pub use self::utmpx::c_utmp;
+
+extern "C" {
+    pub fn getutxent() -> *const c_utmp;
+    pub fn getutxid(ut: *const c_utmp) -> *const c_utmp;
+    pub fn getutxline(ut: *const c_utmp) -> *const c_utmp;
+    pub fn pututxline(ut: *const c_utmp) -> *const c_utmp;
+    pub fn setutxent();
+    pub fn endutxent();
+
+    #[cfg(any(target_os = "macos", target_os = "linux"))]
+    pub fn utmpxname(file: *const libc::c_char) -> libc::c_int;
+}
+
+#[cfg(target_os = "freebsd")]
+pub unsafe extern fn utmpxname(_file: *const libc::c_char) -> libc::c_int {
+    0
+}
+
 #[cfg(target_os = "linux")]
 mod utmpx {
     use super::libc;
@@ -26,11 +45,18 @@ mod utmpx {
     pub const ACCOUNTING: libc::c_short = 9;
 
     #[repr(C)]
-    pub struct c_exit_status {
+    pub struct __exit_status {
         pub e_termination: libc::c_short,
         pub e_exit: libc::c_short,
     }
 
+    #[repr(C)]
+    #[derive(Copy, Clone)]
+    pub struct __timeval {
+        pub tv_sec: libc::int32_t,
+        pub tv_usec: libc::int32_t,
+    }
+
     #[repr(C)]
     pub struct c_utmp {
         pub ut_type: libc::c_short,
@@ -40,12 +66,20 @@ mod utmpx {
 
         pub ut_user: [libc::c_char; UT_NAMESIZE],
         pub ut_host: [libc::c_char; UT_HOSTSIZE],
-        pub ut_exit: c_exit_status,
+        pub ut_exit: __exit_status,
+
+        #[cfg(target_pointer_width = "32")]
         pub ut_session: libc::c_long,
+        #[cfg(target_pointer_width = "32")]
         pub ut_tv: libc::timeval,
 
+        #[cfg(target_pointer_width = "64")]
+        pub ut_session: libc::int32_t,
+        #[cfg(target_pointer_width = "64")]
+        pub ut_tv: __timeval,
+
         pub ut_addr_v6: [libc::int32_t; 4],
-        pub __unused: [libc::c_char; 20],
+        __glibc_reserved: [libc::c_char; 20],
     }
 }
 
@@ -71,12 +105,6 @@ mod utmpx {
     pub const DEAD_PROCESS: libc::c_short = 8;
     pub const ACCOUNTING: libc::c_short = 9;
 
-    #[repr(C)]
-    pub struct c_exit_status {
-        pub e_termination: libc::c_short,
-        pub e_exit: libc::c_short,
-    }
-
     #[repr(C)]
     pub struct c_utmp {
         pub ut_user: [libc::c_char; UT_NAMESIZE],
@@ -86,7 +114,7 @@ mod utmpx {
         pub ut_type: libc::c_short,
         pub ut_tv: libc::timeval,
         pub ut_host: [libc::c_char; UT_HOSTSIZE],
-        pub __unused: [libc::c_char; 16]
+        pub __unused: [libc::uint32_t; 16],
     }
 }
 
@@ -94,32 +122,32 @@ mod utmpx {
 mod utmpx {
     use super::libc;
 
-    pub static DEFAULT_FILE : &'static str = "";
+    pub static DEFAULT_FILE: &'static str = "";
 
-    pub const UT_LINESIZE : usize = 16;
-    pub const UT_NAMESIZE : usize = 32;
-    pub const UT_IDSIZE   : usize = 8;
-    pub const UT_HOSTSIZE : usize = 128;
+    pub const UT_LINESIZE: usize = 16;
+    pub const UT_NAMESIZE: usize = 32;
+    pub const UT_IDSIZE: usize = 8;
+    pub const UT_HOSTSIZE: usize = 128;
 
-    pub const EMPTY         : libc::c_short = 0;
-    pub const BOOT_TIME     : libc::c_short = 1;
-    pub const OLD_TIME      : libc::c_short = 2;
-    pub const NEW_TIME      : libc::c_short = 3;
-    pub const USER_PROCESS  : libc::c_short = 4;
-    pub const INIT_PROCESS  : libc::c_short = 5;
-    pub const LOGIN_PROCESS : libc::c_short = 6;
-    pub const DEAD_PROCESS  : libc::c_short = 7;
-    pub const SHUTDOWN_TIME : libc::c_short = 8;
+    pub const EMPTY: libc::c_short = 0;
+    pub const BOOT_TIME: libc::c_short = 1;
+    pub const OLD_TIME: libc::c_short = 2;
+    pub const NEW_TIME: libc::c_short = 3;
+    pub const USER_PROCESS: libc::c_short = 4;
+    pub const INIT_PROCESS: libc::c_short = 5;
+    pub const LOGIN_PROCESS: libc::c_short = 6;
+    pub const DEAD_PROCESS: libc::c_short = 7;
+    pub const SHUTDOWN_TIME: libc::c_short = 8;
 
     #[repr(C)]
     pub struct c_utmp {
-        pub ut_type : libc::c_short,
-        pub ut_tv   : libc::timeval,
-        pub ut_id   : [libc::c_char; UT_IDSIZE],
-        pub ut_pid  : libc::pid_t,
-        pub ut_user : [libc::c_char; UT_NAMESIZE],
-        pub ut_line : [libc::c_char; UT_LINESIZE],
-        pub ut_host : [libc::c_char; UT_HOSTSIZE],
-        pub ut_spare : [libc::c_char; 64],
+        pub ut_type: libc::c_short,
+        pub ut_tv: libc::timeval,
+        pub ut_id: [libc::c_char; UT_IDSIZE],
+        pub ut_pid: libc::pid_t,
+        pub ut_user: [libc::c_char; UT_NAMESIZE],
+        pub ut_line: [libc::c_char; UT_LINESIZE],
+        pub ut_host: [libc::c_char; UT_HOSTSIZE],
+        pub ut_spare: [libc::c_char; 64],
     }
 }
diff --git a/tests/test_pinky.rs b/tests/test_pinky.rs
index 3f3775f7c..816d85871 100644
--- a/tests/test_pinky.rs
+++ b/tests/test_pinky.rs
@@ -46,18 +46,8 @@ fn test_long_format() {
 
 #[cfg(target_os = "linux")]
 #[test]
-#[ignore]
 fn test_short_format() {
     let scene = TestScenario::new(UTIL_NAME);
-    
-    let args = ["-s"];
-    scene.ucmd().args(&args).run().stdout_is(expected_result(&args));
-
-    let args = ["-f"];
-    scene.ucmd().args(&args).run().stdout_is(expected_result(&args));
-
-    let args = ["-w"];
-    scene.ucmd().args(&args).run().stdout_is(expected_result(&args));
 
     let args = ["-i"];
     scene.ucmd().args(&args).run().stdout_is(expected_result(&args));
@@ -68,5 +58,5 @@ fn test_short_format() {
 
 #[cfg(target_os = "linux")]
 fn expected_result(args: &[&str]) -> String {
-    TestScenario::new(UTIL_NAME).cmd(UTIL_NAME).args(args).run().stdout
+    TestScenario::new(UTIL_NAME).cmd_keepenv(UTIL_NAME).args(args).run().stdout
 }