src/test/run-pass/issue-30490.rs

   1 // Copyright 2015 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 // ignore-cloudabi no processes
  12 // ignore-emscripten no processes
  13
  14 // Previously libstd would set stdio descriptors of a child process
  15 // by `dup`ing the requested descriptors to inherit directly into the
  16 // stdio descriptors. This, however, would incorrectly handle cases
  17 // where the descriptors to inherit were already stdio descriptors.
  18 // This test checks to avoid that regression.
  19
  20 #![cfg_attr(unix, feature(libc))]
  21 #![cfg_attr(windows, allow(unused_imports))]
  22
  23 #[cfg(unix)]
  24 extern crate libc;
  25
  26 use std::fs::File;
  27 use std::io::{Read, Write};
  28 use std::io::{stdout, stderr};
  29 use std::process::{Command, Stdio};
  30
  31 #[cfg(unix)]
  32 use std::os::unix::io::FromRawFd;
  33
  34 #[cfg(not(unix))]
  35 fn main() {
  36     // Bug not present in Windows
  37 }
  38
  39 #[cfg(unix)]
  40 fn main() {
  41     let mut args = std::env::args();
  42     let name = args.next().unwrap();
  43     let args: Vec<String> = args.collect();
  44     if let Some("--child") = args.get(0).map(|s| &**s) {
  45         return child();
  46     } else if !args.is_empty() {
  47         panic!("unknown options");
  48     }
  49
  50     let stdout_backup = unsafe { libc::dup(libc::STDOUT_FILENO) };
  51     let stderr_backup = unsafe { libc::dup(libc::STDERR_FILENO) };
  52     assert!(stdout_backup > -1);
  53     assert!(stderr_backup > -1);
  54
  55     let (stdout_reader, stdout_writer) = pipe();
  56     let (stderr_reader, stderr_writer) = pipe();
  57     assert!(unsafe { libc::dup2(stdout_writer, libc::STDOUT_FILENO) } > -1);
  58     assert!(unsafe { libc::dup2(stderr_writer, libc::STDERR_FILENO) } > -1);
  59
  60     // Make sure we close any duplicates of the writer end of the pipe,
  61     // otherwise we can get stuck reading from the pipe which has open
  62     // writers but no one supplying any input
  63     assert_eq!(unsafe { libc::close(stdout_writer) }, 0);
  64     assert_eq!(unsafe { libc::close(stderr_writer) }, 0);
  65
  66     stdout().write_all("parent stdout\n".as_bytes()).expect("failed to write to stdout");
  67     stderr().write_all("parent stderr\n".as_bytes()).expect("failed to write to stderr");
  68
  69     let child = {
  70         Command::new(name)
  71             .arg("--child")
  72             .stdin(Stdio::inherit())
  73             .stdout(unsafe { Stdio::from_raw_fd(libc::STDERR_FILENO) })
  74             .stderr(unsafe { Stdio::from_raw_fd(libc::STDOUT_FILENO) })
  75             .spawn()
  76     };
  77
  78     // The Stdio passed into the Command took over (and closed) std{out, err}
  79     // so we should restore them as they were.
  80     assert!(unsafe { libc::dup2(stdout_backup, libc::STDOUT_FILENO) } > -1);
  81     assert!(unsafe { libc::dup2(stderr_backup, libc::STDERR_FILENO) } > -1);
  82
  83     // Using File as a shim around the descriptor
  84     let mut read = String::new();
  85     let mut f: File = unsafe { FromRawFd::from_raw_fd(stdout_reader) };
  86     f.read_to_string(&mut read).expect("failed to read from stdout file");
  87     assert_eq!(read, "parent stdout\nchild stderr\n");
  88
  89     // Using File as a shim around the descriptor
  90     read.clear();
  91     let mut f: File = unsafe { FromRawFd::from_raw_fd(stderr_reader) };
  92     f.read_to_string(&mut read).expect("failed to read from stderr file");
  93     assert_eq!(read, "parent stderr\nchild stdout\n");
  94
  95     assert!(child.expect("failed to execute child process").wait().unwrap().success());
  96 }
  97
  98 #[cfg(unix)]
  99 fn child() {
 100     stdout().write_all("child stdout\n".as_bytes()).expect("child failed to write to stdout");
 101     stderr().write_all("child stderr\n".as_bytes()).expect("child failed to write to stderr");
 102 }
 103
 104 #[cfg(unix)]
 105 /// Returns a pipe (reader, writer combo)
 106 fn pipe() -> (i32, i32) {
 107      let mut fds = [0; 2];
 108      assert_eq!(unsafe { libc::pipe(fds.as_mut_ptr()) }, 0);
 109      (fds[0], fds[1])
 110 }