select: add pselect syscall

Author: abbradar

src/sys/select.rs

@@ -1,8 +1,9 @@
-use std::ptr::null_mut;
+use std::ptr::{null, null_mut};
 use std::os::unix::io::RawFd;
-use libc::c_int;
-use {Errno, Result};
+use libc::{c_int, timespec};
+use {Error, Errno, Result};
 use sys::time::TimeVal;
+use sys::signal::sigset_t;
 
 pub const FD_SETSIZE: RawFd = 1024;
 
@@ -54,8 +55,9 @@ impl FdSet {
 }
 
 mod ffi {
-    use libc::c_int;
+    use libc::{c_int, timespec};
     use sys::time::TimeVal;
+    use sys::signal::sigset_t;
     use super::FdSet;
 
     extern {
@@ -64,6 +66,13 @@ mod ffi {
                       writefds: *mut FdSet,
                       errorfds: *mut FdSet,
                       timeout: *mut TimeVal) -> c_int;
+
+        pub fn pselect(nfds: c_int,
+                       readfds: *mut FdSet,
+                       writefds: *mut FdSet,
+                       errorfds: *mut FdSet,
+                       timeout: *const timespec,
+                       sigmask: *const sigset_t) -> c_int;
     }
 }
 
@@ -83,3 +92,22 @@ pub fn select(nfds: c_int,
 
     Errno::result(res)
 }
+
+pub fn pselect(nfds: c_int,
+               readfds: Option<&mut FdSet>,
+               writefds: Option<&mut FdSet>,
+               errorfds: Option<&mut FdSet>,
+               timeout: Option<&timespec>,
+               sigmask: Option<&sigset_t>) -> Result<c_int> {
+    let readfds = readfds.map(|set| set as *mut FdSet).unwrap_or(null_mut());
+    let writefds = writefds.map(|set| set as *mut FdSet).unwrap_or(null_mut());
+    let errorfds = errorfds.map(|set| set as *mut FdSet).unwrap_or(null_mut());
+    let timeout = timeout.map(|ts| ts as *const timespec).unwrap_or(null());
+    let sigmask = sigmask.map(|sm| sm as *const sigset_t).unwrap_or(null());
+
+    let res = unsafe {
+        ffi::pselect(nfds, readfds, writefds, errorfds, timeout, sigmask)
+    };
+
+    Errno::result(res)
+}