Newtypes for uid_t, gid_t and pid_t.

Note about newtypes added to changelog.

Changed passing by value to passing by reference in Uid::is_root().

Added documentation

Improved entry about newtypes in CHANGELOG.

Compare self with ROOT constant in `is_root()` method.

Author: Kixunil

CHANGELOG.md

@@ -32,6 +32,9 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 - Changed type signature of `sys::select::FdSet::contains` to make `self`
   immutable ([#564](https://github.com/nix-rust/nix/pull/564))
 - Changed type of `sched::sched_setaffinity`'s `pid` argument to `pid_t`
+- Introduced wrapper types for gid_t, pid_t, and uid_t as Gid, Pid, and Uid
+  respectively. Various functions have been changed to use these new types as
+  arguments. ([#629](https://github.com/nix-rust/nix/pull/629))
 
 ### Removed
 - Removed io::Error from nix::Error and conversion from nix::Error to Errno

src/sched.rs

@@ -1,8 +1,9 @@
 use std::mem;
 use std::os::unix::io::RawFd;
 use std::option::Option;
-use libc::{self, c_int, c_void, pid_t};
+use libc::{self, c_int, c_void};
 use {Errno, Error, Result};
+use ::unistd::Pid;
 
 // For some functions taking with a parameter of type CloneFlags,
 // only a subset of these flags have an effect.
@@ -91,9 +92,9 @@ mod ffi {
     }
 }
 
-pub fn sched_setaffinity(pid: pid_t, cpuset: &CpuSet) -> Result<()> {
+pub fn sched_setaffinity(pid: Pid, cpuset: &CpuSet) -> Result<()> {
     let res = unsafe {
-        libc::sched_setaffinity(pid,
+        libc::sched_setaffinity(pid.into(),
                                 mem::size_of::<CpuSet>() as libc::size_t,
                                 mem::transmute(cpuset))
     };
@@ -105,7 +106,7 @@ pub fn clone(mut cb: CloneCb,
              stack: &mut [u8],
              flags: CloneFlags,
              signal: Option<c_int>)
-             -> Result<pid_t> {
+             -> Result<Pid> {
     extern "C" fn callback(data: *mut CloneCb) -> c_int {
         let cb: &mut CloneCb = unsafe { &mut *data };
         (*cb)() as c_int
@@ -121,7 +122,7 @@ pub fn clone(mut cb: CloneCb,
                    &mut cb)
     };
 
-    Errno::result(res)
+    Errno::result(res).map(Pid::from_raw)
 }
 
 pub fn unshare(flags: CloneFlags) -> Result<()> {

src/sys/ptrace.rs

@@ -1,6 +1,7 @@
 use std::{mem, ptr};
 use {Errno, Error, Result};
-use libc::{pid_t, c_void, c_long, siginfo_t};
+use libc::{c_void, c_long, siginfo_t};
+use ::unistd::Pid;
 
 #[cfg(all(target_os = "linux",
           any(target_arch = "x86",
@@ -74,7 +75,7 @@ mod ffi {
 
 /// Performs a ptrace request. If the request in question is provided by a specialised function
 /// this function will return an unsupported operation error.
-pub fn ptrace(request: ptrace::PtraceRequest, pid: pid_t, addr: *mut c_void, data: *mut c_void) -> Result<c_long> {
+pub fn ptrace(request: ptrace::PtraceRequest, pid: Pid, addr: *mut c_void, data: *mut c_void) -> Result<c_long> {
     use self::ptrace::*;
 
     match request {
@@ -84,10 +85,10 @@ pub fn ptrace(request: ptrace::PtraceRequest, pid: pid_t, addr: *mut c_void, dat
     }
 }
 
-fn ptrace_peek(request: ptrace::PtraceRequest, pid: pid_t, addr: *mut c_void, data: *mut c_void) -> Result<c_long> {
+fn ptrace_peek(request: ptrace::PtraceRequest, pid: Pid, addr: *mut c_void, data: *mut c_void) -> Result<c_long> {
     let ret = unsafe {
         Errno::clear();
-        ffi::ptrace(request, pid, addr, data)
+        ffi::ptrace(request, pid.into(), addr, data)
     };
     match Errno::result(ret) {
         Ok(..) | Err(Error::Sys(Errno::UnknownErrno)) => Ok(ret),
@@ -99,7 +100,7 @@ fn ptrace_peek(request: ptrace::PtraceRequest, pid: pid_t, addr: *mut c_void, da
 /// Some ptrace get requests populate structs or larger elements than c_long
 /// and therefore use the data field to return values. This function handles these
 /// requests.
-fn ptrace_get_data<T>(request: ptrace::PtraceRequest, pid: pid_t) -> Result<T> {
+fn ptrace_get_data<T>(request: ptrace::PtraceRequest, pid: Pid) -> Result<T> {
     // Creates an uninitialized pointer to store result in 
     let data: Box<T> = Box::new(unsafe { mem::uninitialized() });
     let data: *mut c_void = unsafe { mem::transmute(data) };
@@ -109,36 +110,36 @@ fn ptrace_get_data<T>(request: ptrace::PtraceRequest, pid: pid_t) -> Result<T> {
     Ok(*data)
 }
 
-fn ptrace_other(request: ptrace::PtraceRequest, pid: pid_t, addr: *mut c_void, data: *mut c_void) -> Result<c_long> {
-    Errno::result(unsafe { ffi::ptrace(request, pid, addr, data) }).map(|_| 0)
+fn ptrace_other(request: ptrace::PtraceRequest, pid: Pid, addr: *mut c_void, data: *mut c_void) -> Result<c_long> {
+    Errno::result(unsafe { ffi::ptrace(request, pid.into(), addr, data) }).map(|_| 0)
 }
 
 /// Set options, as with `ptrace(PTRACE_SETOPTIONS,...)`.
-pub fn ptrace_setoptions(pid: pid_t, options: ptrace::PtraceOptions) -> Result<()> {
+pub fn ptrace_setoptions(pid: Pid, options: ptrace::PtraceOptions) -> Result<()> {
     use self::ptrace::*;
     use std::ptr;
 
     ptrace(PTRACE_SETOPTIONS, pid, ptr::null_mut(), options as *mut c_void).map(drop)
 }
 
 /// Gets a ptrace event as described by `ptrace(PTRACE_GETEVENTMSG,...)`
-pub fn ptrace_getevent(pid: pid_t) -> Result<c_long> {
+pub fn ptrace_getevent(pid: Pid) -> Result<c_long> {
     use self::ptrace::*;
     ptrace_get_data::<c_long>(PTRACE_GETEVENTMSG, pid)
 }
 
 /// Get siginfo as with `ptrace(PTRACE_GETSIGINFO,...)`
-pub fn ptrace_getsiginfo(pid: pid_t) -> Result<siginfo_t> {
+pub fn ptrace_getsiginfo(pid: Pid) -> Result<siginfo_t> {
     use self::ptrace::*;
     ptrace_get_data::<siginfo_t>(PTRACE_GETSIGINFO, pid)
 }
 
 /// Set siginfo as with `ptrace(PTRACE_SETSIGINFO,...)`
-pub fn ptrace_setsiginfo(pid: pid_t, sig: &siginfo_t) -> Result<()> {
+pub fn ptrace_setsiginfo(pid: Pid, sig: &siginfo_t) -> Result<()> {
     use self::ptrace::*;
     let ret = unsafe{
         Errno::clear();
-        ffi::ptrace(PTRACE_SETSIGINFO, pid, ptr::null_mut(), sig as *const _ as *const c_void)
+        ffi::ptrace(PTRACE_SETSIGINFO, pid.into(), ptr::null_mut(), sig as *const _ as *const c_void)
     };
     match Errno::result(ret) {
         Ok(_) => Ok(()),

src/sys/signal.rs

@@ -409,8 +409,8 @@ pub fn pthread_sigmask(how: SigmaskHow,
     Errno::result(res).map(drop)
 }
 
-pub fn kill<T: Into<Option<Signal>>>(pid: libc::pid_t, signal: T) -> Result<()> {
-    let res = unsafe { libc::kill(pid,
+pub fn kill<T: Into<Option<Signal>>>(pid: ::unistd::Pid, signal: T) -> Result<()> {
+    let res = unsafe { libc::kill(pid.into(),
                                   match signal.into() {
                                       Some(s) => s as libc::c_int,
                                       None => 0,

src/sys/wait.rs

@@ -1,5 +1,6 @@
-use libc::{self, pid_t, c_int};
+use libc::{self, c_int};
 use {Errno, Result};
+use unistd::Pid;
 
 use sys::signal::Signal;
 
@@ -41,12 +42,12 @@ const WSTOPPED: WaitPidFlag = WUNTRACED;
 
 #[derive(Eq, PartialEq, Clone, Copy, Debug)]
 pub enum WaitStatus {
-    Exited(pid_t, i8),
-    Signaled(pid_t, Signal, bool),
-    Stopped(pid_t, Signal),
+    Exited(Pid, i8),
+    Signaled(Pid, Signal, bool),
+    Stopped(Pid, Signal),
     #[cfg(any(target_os = "linux", target_os = "android"))]
-    PtraceEvent(pid_t, Signal, c_int),
-    Continued(pid_t),
+    PtraceEvent(Pid, Signal, c_int),
+    Continued(Pid),
     StillAlive
 }
 
@@ -185,15 +186,15 @@ mod status {
     }
 }
 
-fn decode(pid : pid_t, status: i32) -> WaitStatus {
+fn decode(pid : Pid, status: i32) -> WaitStatus {
     if status::exited(status) {
         WaitStatus::Exited(pid, status::exit_status(status))
     } else if status::signaled(status) {
         WaitStatus::Signaled(pid, status::term_signal(status), status::dumped_core(status))
     } else if status::stopped(status) {
         cfg_if! {
             if #[cfg(any(target_os = "linux", target_os = "android"))] {
-                fn decode_stopped(pid: pid_t, status: i32) -> WaitStatus {
+                fn decode_stopped(pid: Pid, status: i32) -> WaitStatus {
                     let status_additional = status::stop_additional(status);
                     if status_additional == 0 {
                         WaitStatus::Stopped(pid, status::stop_signal(status))
@@ -202,7 +203,7 @@ fn decode(pid : pid_t, status: i32) -> WaitStatus {
                     }
                 }
             } else {
-                fn decode_stopped(pid: pid_t, status: i32) -> WaitStatus {
+                fn decode_stopped(pid: Pid, status: i32) -> WaitStatus {
                     WaitStatus::Stopped(pid, status::stop_signal(status))
                 }
             }
@@ -214,7 +215,7 @@ fn decode(pid : pid_t, status: i32) -> WaitStatus {
     }
 }
 
-pub fn waitpid(pid: pid_t, options: Option<WaitPidFlag>) -> Result<WaitStatus> {
+pub fn waitpid<P: Into<Option<Pid>>>(pid: P, options: Option<WaitPidFlag>) -> Result<WaitStatus> {
     use self::WaitStatus::*;
 
     let mut status: i32 = 0;
@@ -224,14 +225,14 @@ pub fn waitpid(pid: pid_t, options: Option<WaitPidFlag>) -> Result<WaitStatus> {
         None => 0
     };
 
-    let res = unsafe { ffi::waitpid(pid as pid_t, &mut status as *mut c_int, option_bits) };
+    let res = unsafe { ffi::waitpid(pid.into().unwrap_or(Pid::from_raw(-1)).into(), &mut status as *mut c_int, option_bits) };
 
     Ok(match try!(Errno::result(res)) {
         0 => StillAlive,
-        res => decode(res, status),
+        res => decode(Pid::from_raw(res), status),
     })
 }
 
 pub fn wait() -> Result<WaitStatus> {
-    waitpid(-1, None)
+    waitpid(None, None)
 }