Added AddressType type

This was added to the BSD ptrace API and probably should have been added to tyhe linux API to make it easier to write code for both platforms without the user having to reexport the types to their own crate.

src/sys/ptrace/linux.rs

@@ -7,6 +7,7 @@ use libc::{self, c_void, c_long, siginfo_t};
 use ::unistd::Pid;
 use sys::signal::Signal;
 
+pub type AddressType = *mut ::libc::c_void;
 
 cfg_if! {
     if #[cfg(any(all(target_os = "linux", arch = "s390x"),
@@ -170,7 +171,7 @@ libc_bitflags! {
     since="0.10.0",
     note="usages of `ptrace()` should be replaced with the specialized helper functions instead"
 )]
-pub unsafe fn ptrace(request: Request, pid: Pid, addr: *mut c_void, data: *mut c_void) -> Result<c_long> {
+pub unsafe fn ptrace(request: Request, pid: Pid, addr: AddressType, data: *mut c_void) -> Result<c_long> {
     use self::Request::*;
     match request {
         PTRACE_PEEKTEXT | PTRACE_PEEKDATA | PTRACE_PEEKUSER | PTRACE_GETSIGINFO | 
@@ -181,7 +182,7 @@ pub unsafe fn ptrace(request: Request, pid: Pid, addr: *mut c_void, data: *mut c
     }
 }
 
-fn ptrace_peek(request: Request, pid: Pid, addr: *mut c_void, data: *mut c_void) -> Result<c_long> {
+fn ptrace_peek(request: Request, pid: Pid, addr: AddressType, data: *mut c_void) -> Result<c_long> {
     let ret = unsafe {
         Errno::clear();
         libc::ptrace(request as RequestType, libc::pid_t::from(pid), addr, data)
@@ -209,7 +210,7 @@ fn ptrace_get_data<T>(request: Request, pid: Pid) -> Result<T> {
     Ok(data)
 }
 
-unsafe fn ptrace_other(request: Request, pid: Pid, addr: *mut c_void, data: *mut c_void) -> Result<c_long> {
+unsafe fn ptrace_other(request: Request, pid: Pid, addr: AddressType, data: *mut c_void) -> Result<c_long> {
     Errno::result(libc::ptrace(request as RequestType, libc::pid_t::from(pid), addr, data)).map(|_| 0)
 }
 
@@ -368,12 +369,12 @@ pub fn step<T: Into<Option<Signal>>>(pid: Pid, sig: T) -> Result<()> {
 
 
 /// Reads a word from a processes memory at the given address
-pub fn read(pid: Pid, addr: *mut c_void) -> Result<c_long> {
+pub fn read(pid: Pid, addr: AddressType) -> Result<c_long> {
     ptrace_peek(Request::PTRACE_PEEKDATA, pid, addr, ptr::null_mut())
 }
 
 /// Writes a word into the processes memory at the given address
-pub fn write(pid: Pid, addr: *mut c_void, data: *mut c_void) -> Result<()> {
+pub fn write(pid: Pid, addr: AddressType, data: *mut c_void) -> Result<()> {
     unsafe {
         ptrace_other(Request::PTRACE_POKEDATA, pid, addr, data).map(|_| ())
     }