src/libstd/process.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 //! Working with processes.
  12
  13 #![stable(feature = "process", since = "1.0.0")]
  14
  15 use prelude::v1::*;
  16 use io::prelude::*;
  17
  18 use ffi::OsStr;
  19 use fmt;
  20 use io;
  21 use path::Path;
  22 use str;
  23 use sys::pipe::{read2, AnonPipe};
  24 use sys::process as imp;
  25 use sys_common::{AsInner, AsInnerMut, FromInner, IntoInner};
  26
  27 /// Representation of a running or exited child process.
  28 ///
  29 /// This structure is used to represent and manage child processes. A child
  30 /// process is created via the `Command` struct, which configures the spawning
  31 /// process and can itself be constructed using a builder-style interface.
  32 ///
  33 /// # Examples
  34 ///
  35 /// ```should_panic
  36 /// use std::process::Command;
  37 ///
  38 /// let mut child = Command::new("/bin/cat")
  39 ///                         .arg("file.txt")
  40 ///                         .spawn()
  41 ///                         .unwrap_or_else(|e| { panic!("failed to execute child: {}", e) });
  42 ///
  43 /// let ecode = child.wait()
  44 ///                  .unwrap_or_else(|e| { panic!("failed to wait on child: {}", e) });
  45 ///
  46 /// assert!(ecode.success());
  47 /// ```
  48 ///
  49 /// # Note
  50 ///
  51 /// Take note that there is no implementation of
  52 /// [`Drop`](../../core/ops/trait.Drop.html) for child processes, so if you
  53 /// do not ensure the `Child` has exited then it will continue to run, even
  54 /// after the `Child` handle to the child process has gone out of scope.
  55 ///
  56 /// Calling `wait` (or other functions that wrap around it) will make the
  57 /// parent process wait until the child has actually exited before continuing.
  58 #[stable(feature = "process", since = "1.0.0")]
  59 pub struct Child {
  60     handle: imp::Process,
  61
  62     /// The handle for writing to the child's stdin, if it has been captured
  63     #[stable(feature = "process", since = "1.0.0")]
  64     pub stdin: Option<ChildStdin>,
  65
  66     /// The handle for reading from the child's stdout, if it has been captured
  67     #[stable(feature = "process", since = "1.0.0")]
  68     pub stdout: Option<ChildStdout>,
  69
  70     /// The handle for reading from the child's stderr, if it has been captured
  71     #[stable(feature = "process", since = "1.0.0")]
  72     pub stderr: Option<ChildStderr>,
  73 }
  74
  75 impl AsInner<imp::Process> for Child {
  76     fn as_inner(&self) -> &imp::Process { &self.handle }
  77 }
  78
  79 impl FromInner<(imp::Process, imp::StdioPipes)> for Child {
  80     fn from_inner((handle, io): (imp::Process, imp::StdioPipes)) -> Child {
  81         Child {
  82             handle: handle,
  83             stdin: io.stdin.map(ChildStdin::from_inner),
  84             stdout: io.stdout.map(ChildStdout::from_inner),
  85             stderr: io.stderr.map(ChildStderr::from_inner),
  86         }
  87     }
  88 }
  89
  90 impl IntoInner<imp::Process> for Child {
  91     fn into_inner(self) -> imp::Process { self.handle }
  92 }
  93
  94 /// A handle to a child process's stdin
  95 #[stable(feature = "process", since = "1.0.0")]
  96 pub struct ChildStdin {
  97     inner: AnonPipe
  98 }
  99
 100 #[stable(feature = "process", since = "1.0.0")]
 101 impl Write for ChildStdin {
 102     fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
 103         self.inner.write(buf)
 104     }
 105
 106     fn flush(&mut self) -> io::Result<()> {
 107         Ok(())
 108     }
 109 }
 110
 111 impl AsInner<AnonPipe> for ChildStdin {
 112     fn as_inner(&self) -> &AnonPipe { &self.inner }
 113 }
 114
 115 impl IntoInner<AnonPipe> for ChildStdin {
 116     fn into_inner(self) -> AnonPipe { self.inner }
 117 }
 118
 119 impl FromInner<AnonPipe> for ChildStdin {
 120     fn from_inner(pipe: AnonPipe) -> ChildStdin {
 121         ChildStdin { inner: pipe }
 122     }
 123 }
 124
 125 /// A handle to a child process's stdout
 126 #[stable(feature = "process", since = "1.0.0")]
 127 pub struct ChildStdout {
 128     inner: AnonPipe
 129 }
 130
 131 #[stable(feature = "process", since = "1.0.0")]
 132 impl Read for ChildStdout {
 133     fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
 134         self.inner.read(buf)
 135     }
 136     fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
 137         self.inner.read_to_end(buf)
 138     }
 139 }
 140
 141 impl AsInner<AnonPipe> for ChildStdout {
 142     fn as_inner(&self) -> &AnonPipe { &self.inner }
 143 }
 144
 145 impl IntoInner<AnonPipe> for ChildStdout {
 146     fn into_inner(self) -> AnonPipe { self.inner }
 147 }
 148
 149 impl FromInner<AnonPipe> for ChildStdout {
 150     fn from_inner(pipe: AnonPipe) -> ChildStdout {
 151         ChildStdout { inner: pipe }
 152     }
 153 }
 154
 155 /// A handle to a child process's stderr
 156 #[stable(feature = "process", since = "1.0.0")]
 157 pub struct ChildStderr {
 158     inner: AnonPipe
 159 }
 160
 161 #[stable(feature = "process", since = "1.0.0")]
 162 impl Read for ChildStderr {
 163     fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
 164         self.inner.read(buf)
 165     }
 166     fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
 167         self.inner.read_to_end(buf)
 168     }
 169 }
 170
 171 impl AsInner<AnonPipe> for ChildStderr {
 172     fn as_inner(&self) -> &AnonPipe { &self.inner }
 173 }
 174
 175 impl IntoInner<AnonPipe> for ChildStderr {
 176     fn into_inner(self) -> AnonPipe { self.inner }
 177 }
 178
 179 impl FromInner<AnonPipe> for ChildStderr {
 180     fn from_inner(pipe: AnonPipe) -> ChildStderr {
 181         ChildStderr { inner: pipe }
 182     }
 183 }
 184
 185 /// The `Command` type acts as a process builder, providing fine-grained control
 186 /// over how a new process should be spawned. A default configuration can be
 187 /// generated using `Command::new(program)`, where `program` gives a path to the
 188 /// program to be executed. Additional builder methods allow the configuration
 189 /// to be changed (for example, by adding arguments) prior to spawning:
 190 ///
 191 /// ```
 192 /// use std::process::Command;
 193 ///
 194 /// let output = Command::new("sh")
 195 ///                      .arg("-c")
 196 ///                      .arg("echo hello")
 197 ///                      .output()
 198 ///                      .unwrap_or_else(|e| { panic!("failed to execute process: {}", e) });
 199 /// let hello = output.stdout;
 200 /// ```
 201 #[stable(feature = "process", since = "1.0.0")]
 202 pub struct Command {
 203     inner: imp::Command,
 204 }
 205
 206 impl Command {
 207     /// Constructs a new `Command` for launching the program at
 208     /// path `program`, with the following default configuration:
 209     ///
 210     /// * No arguments to the program
 211     /// * Inherit the current process's environment
 212     /// * Inherit the current process's working directory
 213     /// * Inherit stdin/stdout/stderr for `spawn` or `status`, but create pipes for `output`
 214     ///
 215     /// Builder methods are provided to change these defaults and
 216     /// otherwise configure the process.
 217     #[stable(feature = "process", since = "1.0.0")]
 218     pub fn new<S: AsRef<OsStr>>(program: S) -> Command {
 219         Command { inner: imp::Command::new(program.as_ref()) }
 220     }
 221
 222     /// Add an argument to pass to the program.
 223     #[stable(feature = "process", since = "1.0.0")]
 224     pub fn arg<S: AsRef<OsStr>>(&mut self, arg: S) -> &mut Command {
 225         self.inner.arg(arg.as_ref());
 226         self
 227     }
 228
 229     /// Add multiple arguments to pass to the program.
 230     #[stable(feature = "process", since = "1.0.0")]
 231     pub fn args<S: AsRef<OsStr>>(&mut self, args: &[S]) -> &mut Command {
 232         for arg in args {
 233             self.arg(arg.as_ref());
 234         }
 235         self
 236     }
 237
 238     /// Inserts or updates an environment variable mapping.
 239     ///
 240     /// Note that environment variable names are case-insensitive (but case-preserving) on Windows,
 241     /// and case-sensitive on all other platforms.
 242     #[stable(feature = "process", since = "1.0.0")]
 243     pub fn env<K, V>(&mut self, key: K, val: V) -> &mut Command
 244         where K: AsRef<OsStr>, V: AsRef<OsStr>
 245     {
 246         self.inner.env(key.as_ref(), val.as_ref());
 247         self
 248     }
 249
 250     /// Removes an environment variable mapping.
 251     #[stable(feature = "process", since = "1.0.0")]
 252     pub fn env_remove<K: AsRef<OsStr>>(&mut self, key: K) -> &mut Command {
 253         self.inner.env_remove(key.as_ref());
 254         self
 255     }
 256
 257     /// Clears the entire environment map for the child process.
 258     #[stable(feature = "process", since = "1.0.0")]
 259     pub fn env_clear(&mut self) -> &mut Command {
 260         self.inner.env_clear();
 261         self
 262     }
 263
 264     /// Sets the working directory for the child process.
 265     #[stable(feature = "process", since = "1.0.0")]
 266     pub fn current_dir<P: AsRef<Path>>(&mut self, dir: P) -> &mut Command {
 267         self.inner.cwd(dir.as_ref().as_ref());
 268         self
 269     }
 270
 271     /// Configuration for the child process's stdin handle (file descriptor 0).
 272     #[stable(feature = "process", since = "1.0.0")]
 273     pub fn stdin(&mut self, cfg: Stdio) -> &mut Command {
 274         self.inner.stdin(cfg.0);
 275         self
 276     }
 277
 278     /// Configuration for the child process's stdout handle (file descriptor 1).
 279     #[stable(feature = "process", since = "1.0.0")]
 280     pub fn stdout(&mut self, cfg: Stdio) -> &mut Command {
 281         self.inner.stdout(cfg.0);
 282         self
 283     }
 284
 285     /// Configuration for the child process's stderr handle (file descriptor 2).
 286     #[stable(feature = "process", since = "1.0.0")]
 287     pub fn stderr(&mut self, cfg: Stdio) -> &mut Command {
 288         self.inner.stderr(cfg.0);
 289         self
 290     }
 291
 292     /// Executes the command as a child process, returning a handle to it.
 293     ///
 294     /// By default, stdin, stdout and stderr are inherited from the parent.
 295     #[stable(feature = "process", since = "1.0.0")]
 296     pub fn spawn(&mut self) -> io::Result<Child> {
 297         self.inner.spawn(imp::Stdio::Inherit, true).map(Child::from_inner)
 298     }
 299
 300     /// Executes the command as a child process, waiting for it to finish and
 301     /// collecting all of its output.
 302     ///
 303     /// By default, stdin, stdout and stderr are captured (and used to
 304     /// provide the resulting output).
 305     ///
 306     /// # Examples
 307     ///
 308     /// ```
 309     /// use std::process::Command;
 310     /// let output = Command::new("cat").arg("foo.txt").output().unwrap_or_else(|e| {
 311     ///     panic!("failed to execute process: {}", e)
 312     /// });
 313     ///
 314     /// println!("status: {}", output.status);
 315     /// println!("stdout: {}", String::from_utf8_lossy(&output.stdout));
 316     /// println!("stderr: {}", String::from_utf8_lossy(&output.stderr));
 317     /// ```
 318     #[stable(feature = "process", since = "1.0.0")]
 319     pub fn output(&mut self) -> io::Result<Output> {
 320         self.inner.spawn(imp::Stdio::MakePipe, false).map(Child::from_inner)
 321             .and_then(|p| p.wait_with_output())
 322     }
 323
 324     /// Executes a command as a child process, waiting for it to finish and
 325     /// collecting its exit status.
 326     ///
 327     /// By default, stdin, stdout and stderr are inherited from the parent.
 328     ///
 329     /// # Examples
 330     ///
 331     /// ```
 332     /// use std::process::Command;
 333     ///
 334     /// let status = Command::new("ls").status().unwrap_or_else(|e| {
 335     ///     panic!("failed to execute process: {}", e)
 336     /// });
 337     ///
 338     /// println!("process exited with: {}", status);
 339     /// ```
 340     #[stable(feature = "process", since = "1.0.0")]
 341     pub fn status(&mut self) -> io::Result<ExitStatus> {
 342         self.inner.spawn(imp::Stdio::Inherit, true).map(Child::from_inner)
 343                   .and_then(|mut p| p.wait())
 344     }
 345 }
 346
 347 #[stable(feature = "rust1", since = "1.0.0")]
 348 impl fmt::Debug for Command {
 349     /// Format the program and arguments of a Command for display. Any
 350     /// non-utf8 data is lossily converted using the utf8 replacement
 351     /// character.
 352     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 353         self.inner.fmt(f)
 354     }
 355 }
 356
 357 impl AsInner<imp::Command> for Command {
 358     fn as_inner(&self) -> &imp::Command { &self.inner }
 359 }
 360
 361 impl AsInnerMut<imp::Command> for Command {
 362     fn as_inner_mut(&mut self) -> &mut imp::Command { &mut self.inner }
 363 }
 364
 365 /// The output of a finished process.
 366 #[derive(PartialEq, Eq, Clone)]
 367 #[stable(feature = "process", since = "1.0.0")]
 368 pub struct Output {
 369     /// The status (exit code) of the process.
 370     #[stable(feature = "process", since = "1.0.0")]
 371     pub status: ExitStatus,
 372     /// The data that the process wrote to stdout.
 373     #[stable(feature = "process", since = "1.0.0")]
 374     pub stdout: Vec<u8>,
 375     /// The data that the process wrote to stderr.
 376     #[stable(feature = "process", since = "1.0.0")]
 377     pub stderr: Vec<u8>,
 378 }
 379
 380 // If either stderr or stdout are valid utf8 strings it prints the valid
 381 // strings, otherwise it prints the byte sequence instead
 382 #[stable(feature = "process_output_debug", since = "1.7.0")]
 383 impl fmt::Debug for Output {
 384     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
 385
 386         let stdout_utf8 = str::from_utf8(&self.stdout);
 387         let stdout_debug: &fmt::Debug = match stdout_utf8 {
 388             Ok(ref str) => str,
 389             Err(_) => &self.stdout
 390         };
 391
 392         let stderr_utf8 = str::from_utf8(&self.stderr);
 393         let stderr_debug: &fmt::Debug = match stderr_utf8 {
 394             Ok(ref str) => str,
 395             Err(_) => &self.stderr
 396         };
 397
 398         fmt.debug_struct("Output")
 399             .field("status", &self.status)
 400             .field("stdout", stdout_debug)
 401             .field("stderr", stderr_debug)
 402             .finish()
 403     }
 404 }
 405
 406 /// Describes what to do with a standard I/O stream for a child process.
 407 #[stable(feature = "process", since = "1.0.0")]
 408 pub struct Stdio(imp::Stdio);
 409
 410 impl Stdio {
 411     /// A new pipe should be arranged to connect the parent and child processes.
 412     #[stable(feature = "process", since = "1.0.0")]
 413     pub fn piped() -> Stdio { Stdio(imp::Stdio::MakePipe) }
 414
 415     /// The child inherits from the corresponding parent descriptor.
 416     #[stable(feature = "process", since = "1.0.0")]
 417     pub fn inherit() -> Stdio { Stdio(imp::Stdio::Inherit) }
 418
 419     /// This stream will be ignored. This is the equivalent of attaching the
 420     /// stream to `/dev/null`
 421     #[stable(feature = "process", since = "1.0.0")]
 422     pub fn null() -> Stdio { Stdio(imp::Stdio::Null) }
 423 }
 424
 425 impl FromInner<imp::Stdio> for Stdio {
 426     fn from_inner(inner: imp::Stdio) -> Stdio {
 427         Stdio(inner)
 428     }
 429 }
 430
 431 /// Describes the result of a process after it has terminated.
 432 #[derive(PartialEq, Eq, Clone, Copy, Debug)]
 433 #[stable(feature = "process", since = "1.0.0")]
 434 pub struct ExitStatus(imp::ExitStatus);
 435
 436 impl ExitStatus {
 437     /// Was termination successful? Signal termination not considered a success,
 438     /// and success is defined as a zero exit status.
 439     #[stable(feature = "process", since = "1.0.0")]
 440     pub fn success(&self) -> bool {
 441         self.0.success()
 442     }
 443
 444     /// Returns the exit code of the process, if any.
 445     ///
 446     /// On Unix, this will return `None` if the process was terminated
 447     /// by a signal; `std::os::unix` provides an extension trait for
 448     /// extracting the signal and other details from the `ExitStatus`.
 449     #[stable(feature = "process", since = "1.0.0")]
 450     pub fn code(&self) -> Option<i32> {
 451         self.0.code()
 452     }
 453 }
 454
 455 impl AsInner<imp::ExitStatus> for ExitStatus {
 456     fn as_inner(&self) -> &imp::ExitStatus { &self.0 }
 457 }
 458
 459 #[stable(feature = "process", since = "1.0.0")]
 460 impl fmt::Display for ExitStatus {
 461     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 462         self.0.fmt(f)
 463     }
 464 }
 465
 466 impl Child {
 467     /// Forces the child to exit. This is equivalent to sending a
 468     /// SIGKILL on unix platforms.
 469     #[stable(feature = "process", since = "1.0.0")]
 470     pub fn kill(&mut self) -> io::Result<()> {
 471         self.handle.kill()
 472     }
 473
 474     /// Returns the OS-assigned process identifier associated with this child.
 475     #[stable(feature = "process_id", since = "1.3.0")]
 476     pub fn id(&self) -> u32 {
 477         self.handle.id()
 478     }
 479
 480     /// Waits for the child to exit completely, returning the status that it
 481     /// exited with. This function will continue to have the same return value
 482     /// after it has been called at least once.
 483     ///
 484     /// The stdin handle to the child process, if any, will be closed
 485     /// before waiting. This helps avoid deadlock: it ensures that the
 486     /// child does not block waiting for input from the parent, while
 487     /// the parent waits for the child to exit.
 488     #[stable(feature = "process", since = "1.0.0")]
 489     pub fn wait(&mut self) -> io::Result<ExitStatus> {
 490         drop(self.stdin.take());
 491         self.handle.wait().map(ExitStatus)
 492     }
 493
 494     /// Simultaneously waits for the child to exit and collect all remaining
 495     /// output on the stdout/stderr handles, returning an `Output`
 496     /// instance.
 497     ///
 498     /// The stdin handle to the child process, if any, will be closed
 499     /// before waiting. This helps avoid deadlock: it ensures that the
 500     /// child does not block waiting for input from the parent, while
 501     /// the parent waits for the child to exit.
 502     #[stable(feature = "process", since = "1.0.0")]
 503     pub fn wait_with_output(mut self) -> io::Result<Output> {
 504         drop(self.stdin.take());
 505
 506         let (mut stdout, mut stderr) = (Vec::new(), Vec::new());
 507         match (self.stdout.take(), self.stderr.take()) {
 508             (None, None) => {}
 509             (Some(mut out), None) => {
 510                 let res = out.read_to_end(&mut stdout);
 511                 res.unwrap();
 512             }
 513             (None, Some(mut err)) => {
 514                 let res = err.read_to_end(&mut stderr);
 515                 res.unwrap();
 516             }
 517             (Some(out), Some(err)) => {
 518                 let res = read2(out.inner, &mut stdout, err.inner, &mut stderr);
 519                 res.unwrap();
 520             }
 521         }
 522
 523         let status = self.wait()?;
 524         Ok(Output {
 525             status: status,
 526             stdout: stdout,
 527             stderr: stderr,
 528         })
 529     }
 530 }
 531
 532 /// Terminates the current process with the specified exit code.
 533 ///
 534 /// This function will never return and will immediately terminate the current
 535 /// process. The exit code is passed through to the underlying OS and will be
 536 /// available for consumption by another process.
 537 ///
 538 /// Note that because this function never returns, and that it terminates the
 539 /// process, no destructors on the current stack or any other thread's stack
 540 /// will be run. If a clean shutdown is needed it is recommended to only call
 541 /// this function at a known point where there are no more destructors left
 542 /// to run.
 543 #[stable(feature = "rust1", since = "1.0.0")]
 544 pub fn exit(code: i32) -> ! {
 545     ::sys_common::cleanup();
 546     ::sys::os::exit(code)
 547 }
 548
 549 #[cfg(test)]
 550 mod tests {
 551     use prelude::v1::*;
 552     use io::prelude::*;
 553
 554     use io::ErrorKind;
 555     use str;
 556     use super::{Command, Output, Stdio};
 557
 558     // FIXME(#10380) these tests should not all be ignored on android.
 559
 560     #[test]
 561     #[cfg_attr(target_os = "android", ignore)]
 562     fn smoke() {
 563         let p = Command::new("true").spawn();
 564         assert!(p.is_ok());
 565         let mut p = p.unwrap();
 566         assert!(p.wait().unwrap().success());
 567     }
 568
 569     #[test]
 570     #[cfg_attr(target_os = "android", ignore)]
 571     fn smoke_failure() {
 572         match Command::new("if-this-is-a-binary-then-the-world-has-ended").spawn() {
 573             Ok(..) => panic!(),
 574             Err(..) => {}
 575         }
 576     }
 577
 578     #[test]
 579     #[cfg_attr(target_os = "android", ignore)]
 580     fn exit_reported_right() {
 581         let p = Command::new("false").spawn();
 582         assert!(p.is_ok());
 583         let mut p = p.unwrap();
 584         assert!(p.wait().unwrap().code() == Some(1));
 585         drop(p.wait());
 586     }
 587
 588     #[test]
 589     #[cfg(unix)]
 590     #[cfg_attr(target_os = "android", ignore)]
 591     fn signal_reported_right() {
 592         use os::unix::process::ExitStatusExt;
 593
 594         let mut p = Command::new("/bin/sh")
 595                             .arg("-c").arg("read a")
 596                             .stdin(Stdio::piped())
 597                             .spawn().unwrap();
 598         p.kill().unwrap();
 599         match p.wait().unwrap().signal() {
 600             Some(9) => {},
 601             result => panic!("not terminated by signal 9 (instead, {:?})",
 602                              result),
 603         }
 604     }
 605
 606     pub fn run_output(mut cmd: Command) -> String {
 607         let p = cmd.spawn();
 608         assert!(p.is_ok());
 609         let mut p = p.unwrap();
 610         assert!(p.stdout.is_some());
 611         let mut ret = String::new();
 612         p.stdout.as_mut().unwrap().read_to_string(&mut ret).unwrap();
 613         assert!(p.wait().unwrap().success());
 614         return ret;
 615     }
 616
 617     #[test]
 618     #[cfg_attr(target_os = "android", ignore)]
 619     fn stdout_works() {
 620         let mut cmd = Command::new("echo");
 621         cmd.arg("foobar").stdout(Stdio::piped());
 622         assert_eq!(run_output(cmd), "foobar\n");
 623     }
 624
 625     #[test]
 626     #[cfg_attr(any(windows, target_os = "android"), ignore)]
 627     fn set_current_dir_works() {
 628         let mut cmd = Command::new("/bin/sh");
 629         cmd.arg("-c").arg("pwd")
 630            .current_dir("/")
 631            .stdout(Stdio::piped());
 632         assert_eq!(run_output(cmd), "/\n");
 633     }
 634
 635     #[test]
 636     #[cfg_attr(any(windows, target_os = "android"), ignore)]
 637     fn stdin_works() {
 638         let mut p = Command::new("/bin/sh")
 639                             .arg("-c").arg("read line; echo $line")
 640                             .stdin(Stdio::piped())
 641                             .stdout(Stdio::piped())
 642                             .spawn().unwrap();
 643         p.stdin.as_mut().unwrap().write("foobar".as_bytes()).unwrap();
 644         drop(p.stdin.take());
 645         let mut out = String::new();
 646         p.stdout.as_mut().unwrap().read_to_string(&mut out).unwrap();
 647         assert!(p.wait().unwrap().success());
 648         assert_eq!(out, "foobar\n");
 649     }
 650
 651
 652     #[test]
 653     #[cfg_attr(target_os = "android", ignore)]
 654     #[cfg(unix)]
 655     fn uid_works() {
 656         use os::unix::prelude::*;
 657         use libc;
 658         let mut p = Command::new("/bin/sh")
 659                             .arg("-c").arg("true")
 660                             .uid(unsafe { libc::getuid() })
 661                             .gid(unsafe { libc::getgid() })
 662                             .spawn().unwrap();
 663         assert!(p.wait().unwrap().success());
 664     }
 665
 666     #[test]
 667     #[cfg_attr(target_os = "android", ignore)]
 668     #[cfg(unix)]
 669     fn uid_to_root_fails() {
 670         use os::unix::prelude::*;
 671         use libc;
 672
 673         // if we're already root, this isn't a valid test. Most of the bots run
 674         // as non-root though (android is an exception).
 675         if unsafe { libc::getuid() == 0 } { return }
 676         assert!(Command::new("/bin/ls").uid(0).gid(0).spawn().is_err());
 677     }
 678
 679     #[test]
 680     #[cfg_attr(target_os = "android", ignore)]
 681     fn test_process_status() {
 682         let mut status = Command::new("false").status().unwrap();
 683         assert!(status.code() == Some(1));
 684
 685         status = Command::new("true").status().unwrap();
 686         assert!(status.success());
 687     }
 688
 689     #[test]
 690     fn test_process_output_fail_to_start() {
 691         match Command::new("/no-binary-by-this-name-should-exist").output() {
 692             Err(e) => assert_eq!(e.kind(), ErrorKind::NotFound),
 693             Ok(..) => panic!()
 694         }
 695     }
 696
 697     #[test]
 698     #[cfg_attr(target_os = "android", ignore)]
 699     fn test_process_output_output() {
 700         let Output {status, stdout, stderr}
 701              = Command::new("echo").arg("hello").output().unwrap();
 702         let output_str = str::from_utf8(&stdout).unwrap();
 703
 704         assert!(status.success());
 705         assert_eq!(output_str.trim().to_string(), "hello");
 706         assert_eq!(stderr, Vec::new());
 707     }
 708
 709     #[test]
 710     #[cfg_attr(target_os = "android", ignore)]
 711     fn test_process_output_error() {
 712         let Output {status, stdout, stderr}
 713              = Command::new("mkdir").arg(".").output().unwrap();
 714
 715         assert!(status.code() == Some(1));
 716         assert_eq!(stdout, Vec::new());
 717         assert!(!stderr.is_empty());
 718     }
 719
 720     #[test]
 721     #[cfg_attr(target_os = "android", ignore)]
 722     fn test_finish_once() {
 723         let mut prog = Command::new("false").spawn().unwrap();
 724         assert!(prog.wait().unwrap().code() == Some(1));
 725     }
 726
 727     #[test]
 728     #[cfg_attr(target_os = "android", ignore)]
 729     fn test_finish_twice() {
 730         let mut prog = Command::new("false").spawn().unwrap();
 731         assert!(prog.wait().unwrap().code() == Some(1));
 732         assert!(prog.wait().unwrap().code() == Some(1));
 733     }
 734
 735     #[test]
 736     #[cfg_attr(target_os = "android", ignore)]
 737     fn test_wait_with_output_once() {
 738         let prog = Command::new("echo").arg("hello").stdout(Stdio::piped())
 739             .spawn().unwrap();
 740         let Output {status, stdout, stderr} = prog.wait_with_output().unwrap();
 741         let output_str = str::from_utf8(&stdout).unwrap();
 742
 743         assert!(status.success());
 744         assert_eq!(output_str.trim().to_string(), "hello");
 745         assert_eq!(stderr, Vec::new());
 746     }
 747
 748     #[cfg(all(unix, not(target_os="android")))]
 749     pub fn env_cmd() -> Command {
 750         Command::new("env")
 751     }
 752     #[cfg(target_os="android")]
 753     pub fn env_cmd() -> Command {
 754         let mut cmd = Command::new("/system/bin/sh");
 755         cmd.arg("-c").arg("set");
 756         cmd
 757     }
 758
 759     #[cfg(windows)]
 760     pub fn env_cmd() -> Command {
 761         let mut cmd = Command::new("cmd");
 762         cmd.arg("/c").arg("set");
 763         cmd
 764     }
 765
 766     #[test]
 767     fn test_inherit_env() {
 768         use env;
 769
 770         let result = env_cmd().output().unwrap();
 771         let output = String::from_utf8(result.stdout).unwrap();
 772
 773         for (ref k, ref v) in env::vars() {
 774             // don't check android RANDOM variables
 775             if cfg!(target_os = "android") && *k == "RANDOM" {
 776                 continue
 777             }
 778
 779             // Windows has hidden environment variables whose names start with
 780             // equals signs (`=`). Those do not show up in the output of the
 781             // `set` command.
 782             assert!((cfg!(windows) && k.starts_with("=")) ||
 783                     k.starts_with("DYLD") ||
 784                     output.contains(&format!("{}={}", *k, *v)) ||
 785                     output.contains(&format!("{}='{}'", *k, *v)),
 786                     "output doesn't contain `{}={}`\n{}",
 787                     k, v, output);
 788         }
 789     }
 790
 791     #[test]
 792     fn test_override_env() {
 793         use env;
 794
 795         // In some build environments (such as chrooted Nix builds), `env` can
 796         // only be found in the explicitly-provided PATH env variable, not in
 797         // default places such as /bin or /usr/bin. So we need to pass through
 798         // PATH to our sub-process.
 799         let mut cmd = env_cmd();
 800         cmd.env_clear().env("RUN_TEST_NEW_ENV", "123");
 801         if let Some(p) = env::var_os("PATH") {
 802             cmd.env("PATH", &p);
 803         }
 804         let result = cmd.output().unwrap();
 805         let output = String::from_utf8_lossy(&result.stdout).to_string();
 806
 807         assert!(output.contains("RUN_TEST_NEW_ENV=123"),
 808                 "didn't find RUN_TEST_NEW_ENV inside of:\n\n{}", output);
 809     }
 810
 811     #[test]
 812     fn test_add_to_env() {
 813         let result = env_cmd().env("RUN_TEST_NEW_ENV", "123").output().unwrap();
 814         let output = String::from_utf8_lossy(&result.stdout).to_string();
 815
 816         assert!(output.contains("RUN_TEST_NEW_ENV=123"),
 817                 "didn't find RUN_TEST_NEW_ENV inside of:\n\n{}", output);
 818     }
 819
 820     // Regression tests for #30858.
 821     #[test]
 822     fn test_interior_nul_in_progname_is_error() {
 823         match Command::new("has-some-\0\0s-inside").spawn() {
 824             Err(e) => assert_eq!(e.kind(), ErrorKind::InvalidInput),
 825             Ok(_) => panic!(),
 826         }
 827     }
 828
 829     #[test]
 830     fn test_interior_nul_in_arg_is_error() {
 831         match Command::new("echo").arg("has-some-\0\0s-inside").spawn() {
 832             Err(e) => assert_eq!(e.kind(), ErrorKind::InvalidInput),
 833             Ok(_) => panic!(),
 834         }
 835     }
 836
 837     #[test]
 838     fn test_interior_nul_in_args_is_error() {
 839         match Command::new("echo").args(&["has-some-\0\0s-inside"]).spawn() {
 840             Err(e) => assert_eq!(e.kind(), ErrorKind::InvalidInput),
 841             Ok(_) => panic!(),
 842         }
 843     }
 844
 845     #[test]
 846     fn test_interior_nul_in_current_dir_is_error() {
 847         match Command::new("echo").current_dir("has-some-\0\0s-inside").spawn() {
 848             Err(e) => assert_eq!(e.kind(), ErrorKind::InvalidInput),
 849             Ok(_) => panic!(),
 850         }
 851     }
 852
 853     // Regression tests for #30862.
 854     #[test]
 855     fn test_interior_nul_in_env_key_is_error() {
 856         match env_cmd().env("has-some-\0\0s-inside", "value").spawn() {
 857             Err(e) => assert_eq!(e.kind(), ErrorKind::InvalidInput),
 858             Ok(_) => panic!(),
 859         }
 860     }
 861
 862     #[test]
 863     fn test_interior_nul_in_env_value_is_error() {
 864         match env_cmd().env("key", "has-some-\0\0s-inside").spawn() {
 865             Err(e) => assert_eq!(e.kind(), ErrorKind::InvalidInput),
 866             Ok(_) => panic!(),
 867         }
 868     }
 869 }