Remove allocation, fix pipe example

src/platform/Cargo.toml

@@ -8,6 +8,3 @@ sc = "0.2"
 
 [target.'cfg(target_os = "redox")'.dependencies]
 redox_syscall = "0.1"
-
-[dependencies]
-alloc-no-stdlib = "1.2"

src/platform/src/lib.rs

@@ -3,8 +3,6 @@
 #![no_std]
 #![allow(non_camel_case_types)]
 //TODO #![feature(thread_local)]
-#![feature(alloc)]
-extern crate alloc;
 
 #[cfg(all(not(feature = "no_std"), target_os = "linux"))]
 #[macro_use]

src/platform/src/redox/mod.rs

-extern crate alloc;
-
 use core::ptr;
 use core::slice;
-use alloc::Vec;
 use syscall;
 
 use c_str;
@@ -127,11 +124,11 @@ pub fn open(path: *const c_char, oflag: c_int, mode: mode_t) -> c_int {
 }
 
 pub fn pipe(fds: [c_int; 2]) -> c_int {
-    let usize_vec = fds.iter().map(|x| *x as usize).collect::<Vec<usize>>();
-    let usize_slice = usize_vec.as_slice();
-    let mut usize_arr: [usize; 2] = Default::default();
-    usize_arr.copy_from_slice(usize_slice);
-    e(syscall::pipe2(&mut usize_arr, 0)) as c_int
+    let mut usize_fds: [usize; 2] = [0; 2];
+    let res = e(syscall::pipe2(&mut usize_fds));
+    fds[0] = usize_fds[0] as c_int;
+    fds[1] = usize_fds[1] as c_int;
+    res as c_int
 }
 
 pub fn read(fd: c_int, buf: &mut [u8]) -> ssize_t {

tests/pipe.c

 //http://www2.cs.uregina.ca/~hamilton/courses/330/notes/unix/pipes/pipes.html
+#include <string.h>
 #include <unistd.h>
 
 int main()
@@ -6,18 +7,27 @@ int main()
 
     int pid, pip[2];
     char instring[20];
+    char * outstring = "Hello World!";
 
-    pipe(pip); 
+    pipe(pip);
 
     pid = fork();
     if (pid == 0)           /* child : sends message to parent*/
     {
+        /* close read end */
+        close(pip[0]);
         /* send 7 characters in the string, including end-of-string */
-        write(pip[1], "Hi Mom!", 7);  
+        write(pip[1], outstring, strlen(outstring));
+        /* close write end */
+        close(pip[1]);
     }
     else			/* parent : receives message from child */
     {
+        /* close write end */
+        close(pip[1]);
         /* read from the pipe */
         read(pip[0], instring, 7);
+        /* close read end */
+        close(pip[0]);
     }
 }