library/std/src/sys/windows/process.rs

   1 #![unstable(feature = "process_internals", issue = "none")]
   2
   3 use crate::borrow::Borrow;
   4 use crate::collections::BTreeMap;
   5 use crate::env;
   6 use crate::env::split_paths;
   7 use crate::ffi::{OsStr, OsString};
   8 use crate::fmt;
   9 use crate::fs;
  10 use crate::io::{self, Error, ErrorKind};
  11 use crate::mem;
  12 use crate::os::windows::ffi::OsStrExt;
  13 use crate::path::Path;
  14 use crate::ptr;
  15 use crate::sys::c;
  16 use crate::sys::cvt;
  17 use crate::sys::fs::{File, OpenOptions};
  18 use crate::sys::handle::Handle;
  19 use crate::sys::mutex::Mutex;
  20 use crate::sys::pipe::{self, AnonPipe};
  21 use crate::sys::stdio;
  22 use crate::sys_common::process::CommandEnv;
  23 use crate::sys_common::AsInner;
  24
  25 use libc::{c_void, EXIT_FAILURE, EXIT_SUCCESS};
  26
  27 ////////////////////////////////////////////////////////////////////////////////
  28 // Command
  29 ////////////////////////////////////////////////////////////////////////////////
  30
  31 #[derive(Clone, Debug, Eq, PartialEq, Ord, PartialOrd)]
  32 #[doc(hidden)]
  33 pub struct EnvKey(OsString);
  34
  35 impl From<OsString> for EnvKey {
  36     fn from(mut k: OsString) -> Self {
  37         k.make_ascii_uppercase();
  38         EnvKey(k)
  39     }
  40 }
  41
  42 impl From<EnvKey> for OsString {
  43     fn from(k: EnvKey) -> Self {
  44         k.0
  45     }
  46 }
  47
  48 impl Borrow<OsStr> for EnvKey {
  49     fn borrow(&self) -> &OsStr {
  50         &self.0
  51     }
  52 }
  53
  54 impl AsRef<OsStr> for EnvKey {
  55     fn as_ref(&self) -> &OsStr {
  56         &self.0
  57     }
  58 }
  59
  60 fn ensure_no_nuls<T: AsRef<OsStr>>(str: T) -> io::Result<T> {
  61     if str.as_ref().encode_wide().any(|b| b == 0) {
  62         Err(io::Error::new(ErrorKind::InvalidInput, "nul byte found in provided data"))
  63     } else {
  64         Ok(str)
  65     }
  66 }
  67
  68 pub struct Command {
  69     program: OsString,
  70     args: Vec<OsString>,
  71     env: CommandEnv,
  72     cwd: Option<OsString>,
  73     flags: u32,
  74     detach: bool, // not currently exposed in std::process
  75     stdin: Option<Stdio>,
  76     stdout: Option<Stdio>,
  77     stderr: Option<Stdio>,
  78 }
  79
  80 pub enum Stdio {
  81     Inherit,
  82     Null,
  83     MakePipe,
  84     Handle(Handle),
  85 }
  86
  87 pub struct StdioPipes {
  88     pub stdin: Option<AnonPipe>,
  89     pub stdout: Option<AnonPipe>,
  90     pub stderr: Option<AnonPipe>,
  91 }
  92
  93 struct DropGuard<'a> {
  94     lock: &'a Mutex,
  95 }
  96
  97 impl Command {
  98     pub fn new(program: &OsStr) -> Command {
  99         Command {
 100             program: program.to_os_string(),
 101             args: Vec::new(),
 102             env: Default::default(),
 103             cwd: None,
 104             flags: 0,
 105             detach: false,
 106             stdin: None,
 107             stdout: None,
 108             stderr: None,
 109         }
 110     }
 111
 112     pub fn arg(&mut self, arg: &OsStr) {
 113         self.args.push(arg.to_os_string())
 114     }
 115     pub fn env_mut(&mut self) -> &mut CommandEnv {
 116         &mut self.env
 117     }
 118     pub fn cwd(&mut self, dir: &OsStr) {
 119         self.cwd = Some(dir.to_os_string())
 120     }
 121     pub fn stdin(&mut self, stdin: Stdio) {
 122         self.stdin = Some(stdin);
 123     }
 124     pub fn stdout(&mut self, stdout: Stdio) {
 125         self.stdout = Some(stdout);
 126     }
 127     pub fn stderr(&mut self, stderr: Stdio) {
 128         self.stderr = Some(stderr);
 129     }
 130     pub fn creation_flags(&mut self, flags: u32) {
 131         self.flags = flags;
 132     }
 133
 134     pub fn spawn(
 135         &mut self,
 136         default: Stdio,
 137         needs_stdin: bool,
 138     ) -> io::Result<(Process, StdioPipes)> {
 139         let maybe_env = self.env.capture_if_changed();
 140         // To have the spawning semantics of unix/windows stay the same, we need
 141         // to read the *child's* PATH if one is provided. See #15149 for more
 142         // details.
 143         let program = maybe_env.as_ref().and_then(|env| {
 144             if let Some(v) = env.get(OsStr::new("PATH")) {
 145                 // Split the value and test each path to see if the
 146                 // program exists.
 147                 for path in split_paths(&v) {
 148                     let path = path
 149                         .join(self.program.to_str().unwrap())
 150                         .with_extension(env::consts::EXE_EXTENSION);
 151                     if fs::metadata(&path).is_ok() {
 152                         return Some(path.into_os_string());
 153                     }
 154                 }
 155             }
 156             None
 157         });
 158
 159         let mut si = zeroed_startupinfo();
 160         si.cb = mem::size_of::<c::STARTUPINFO>() as c::DWORD;
 161         si.dwFlags = c::STARTF_USESTDHANDLES;
 162
 163         let program = program.as_ref().unwrap_or(&self.program);
 164         let mut cmd_str = make_command_line(program, &self.args)?;
 165         cmd_str.push(0); // add null terminator
 166
 167         // stolen from the libuv code.
 168         let mut flags = self.flags | c::CREATE_UNICODE_ENVIRONMENT;
 169         if self.detach {
 170             flags |= c::DETACHED_PROCESS | c::CREATE_NEW_PROCESS_GROUP;
 171         }
 172
 173         let (envp, _data) = make_envp(maybe_env)?;
 174         let (dirp, _data) = make_dirp(self.cwd.as_ref())?;
 175         let mut pi = zeroed_process_information();
 176
 177         // Prepare all stdio handles to be inherited by the child. This
 178         // currently involves duplicating any existing ones with the ability to
 179         // be inherited by child processes. Note, however, that once an
 180         // inheritable handle is created, *any* spawned child will inherit that
 181         // handle. We only want our own child to inherit this handle, so we wrap
 182         // the remaining portion of this spawn in a mutex.
 183         //
 184         // For more information, msdn also has an article about this race:
 185         // http://support.microsoft.com/kb/315939
 186         static CREATE_PROCESS_LOCK: Mutex = Mutex::new();
 187         let _guard = DropGuard::new(&CREATE_PROCESS_LOCK);
 188
 189         let mut pipes = StdioPipes { stdin: None, stdout: None, stderr: None };
 190         let null = Stdio::Null;
 191         let default_stdin = if needs_stdin { &default } else { &null };
 192         let stdin = self.stdin.as_ref().unwrap_or(default_stdin);
 193         let stdout = self.stdout.as_ref().unwrap_or(&default);
 194         let stderr = self.stderr.as_ref().unwrap_or(&default);
 195         let stdin = stdin.to_handle(c::STD_INPUT_HANDLE, &mut pipes.stdin)?;
 196         let stdout = stdout.to_handle(c::STD_OUTPUT_HANDLE, &mut pipes.stdout)?;
 197         let stderr = stderr.to_handle(c::STD_ERROR_HANDLE, &mut pipes.stderr)?;
 198         si.hStdInput = stdin.raw();
 199         si.hStdOutput = stdout.raw();
 200         si.hStdError = stderr.raw();
 201
 202         unsafe {
 203             cvt(c::CreateProcessW(
 204                 ptr::null(),
 205                 cmd_str.as_mut_ptr(),
 206                 ptr::null_mut(),
 207                 ptr::null_mut(),
 208                 c::TRUE,
 209                 flags,
 210                 envp,
 211                 dirp,
 212                 &mut si,
 213                 &mut pi,
 214             ))
 215         }?;
 216
 217         // We close the thread handle because we don't care about keeping
 218         // the thread id valid, and we aren't keeping the thread handle
 219         // around to be able to close it later.
 220         drop(Handle::new(pi.hThread));
 221
 222         Ok((Process { handle: Handle::new(pi.hProcess) }, pipes))
 223     }
 224 }
 225
 226 impl fmt::Debug for Command {
 227     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 228         write!(f, "{:?}", self.program)?;
 229         for arg in &self.args {
 230             write!(f, " {:?}", arg)?;
 231         }
 232         Ok(())
 233     }
 234 }
 235
 236 impl<'a> DropGuard<'a> {
 237     fn new(lock: &'a Mutex) -> DropGuard<'a> {
 238         unsafe {
 239             lock.lock();
 240             DropGuard { lock }
 241         }
 242     }
 243 }
 244
 245 impl<'a> Drop for DropGuard<'a> {
 246     fn drop(&mut self) {
 247         unsafe {
 248             self.lock.unlock();
 249         }
 250     }
 251 }
 252
 253 impl Stdio {
 254     fn to_handle(&self, stdio_id: c::DWORD, pipe: &mut Option<AnonPipe>) -> io::Result<Handle> {
 255         match *self {
 256             // If no stdio handle is available, then inherit means that it
 257             // should still be unavailable so propagate the
 258             // INVALID_HANDLE_VALUE.
 259             Stdio::Inherit => match stdio::get_handle(stdio_id) {
 260                 Ok(io) => {
 261                     let io = Handle::new(io);
 262                     let ret = io.duplicate(0, true, c::DUPLICATE_SAME_ACCESS);
 263                     io.into_raw();
 264                     ret
 265                 }
 266                 Err(..) => Ok(Handle::new(c::INVALID_HANDLE_VALUE)),
 267             },
 268
 269             Stdio::MakePipe => {
 270                 let ours_readable = stdio_id != c::STD_INPUT_HANDLE;
 271                 let pipes = pipe::anon_pipe(ours_readable, true)?;
 272                 *pipe = Some(pipes.ours);
 273                 Ok(pipes.theirs.into_handle())
 274             }
 275
 276             Stdio::Handle(ref handle) => handle.duplicate(0, true, c::DUPLICATE_SAME_ACCESS),
 277
 278             // Open up a reference to NUL with appropriate read/write
 279             // permissions as well as the ability to be inherited to child
 280             // processes (as this is about to be inherited).
 281             Stdio::Null => {
 282                 let size = mem::size_of::<c::SECURITY_ATTRIBUTES>();
 283                 let mut sa = c::SECURITY_ATTRIBUTES {
 284                     nLength: size as c::DWORD,
 285                     lpSecurityDescriptor: ptr::null_mut(),
 286                     bInheritHandle: 1,
 287                 };
 288                 let mut opts = OpenOptions::new();
 289                 opts.read(stdio_id == c::STD_INPUT_HANDLE);
 290                 opts.write(stdio_id != c::STD_INPUT_HANDLE);
 291                 opts.security_attributes(&mut sa);
 292                 File::open(Path::new("NUL"), &opts).map(|file| file.into_handle())
 293             }
 294         }
 295     }
 296 }
 297
 298 impl From<AnonPipe> for Stdio {
 299     fn from(pipe: AnonPipe) -> Stdio {
 300         Stdio::Handle(pipe.into_handle())
 301     }
 302 }
 303
 304 impl From<File> for Stdio {
 305     fn from(file: File) -> Stdio {
 306         Stdio::Handle(file.into_handle())
 307     }
 308 }
 309
 310 ////////////////////////////////////////////////////////////////////////////////
 311 // Processes
 312 ////////////////////////////////////////////////////////////////////////////////
 313
 314 /// A value representing a child process.
 315 ///
 316 /// The lifetime of this value is linked to the lifetime of the actual
 317 /// process - the Process destructor calls self.finish() which waits
 318 /// for the process to terminate.
 319 pub struct Process {
 320     handle: Handle,
 321 }
 322
 323 impl Process {
 324     pub fn kill(&mut self) -> io::Result<()> {
 325         cvt(unsafe { c::TerminateProcess(self.handle.raw(), 1) })?;
 326         Ok(())
 327     }
 328
 329     pub fn id(&self) -> u32 {
 330         unsafe { c::GetProcessId(self.handle.raw()) as u32 }
 331     }
 332
 333     pub fn wait(&mut self) -> io::Result<ExitStatus> {
 334         unsafe {
 335             let res = c::WaitForSingleObject(self.handle.raw(), c::INFINITE);
 336             if res != c::WAIT_OBJECT_0 {
 337                 return Err(Error::last_os_error());
 338             }
 339             let mut status = 0;
 340             cvt(c::GetExitCodeProcess(self.handle.raw(), &mut status))?;
 341             Ok(ExitStatus(status))
 342         }
 343     }
 344
 345     pub fn try_wait(&mut self) -> io::Result<Option<ExitStatus>> {
 346         unsafe {
 347             match c::WaitForSingleObject(self.handle.raw(), 0) {
 348                 c::WAIT_OBJECT_0 => {}
 349                 c::WAIT_TIMEOUT => {
 350                     return Ok(None);
 351                 }
 352                 _ => return Err(io::Error::last_os_error()),
 353             }
 354             let mut status = 0;
 355             cvt(c::GetExitCodeProcess(self.handle.raw(), &mut status))?;
 356             Ok(Some(ExitStatus(status)))
 357         }
 358     }
 359
 360     pub fn handle(&self) -> &Handle {
 361         &self.handle
 362     }
 363
 364     pub fn into_handle(self) -> Handle {
 365         self.handle
 366     }
 367 }
 368
 369 #[derive(PartialEq, Eq, Clone, Copy, Debug)]
 370 pub struct ExitStatus(c::DWORD);
 371
 372 impl ExitStatus {
 373     pub fn success(&self) -> bool {
 374         self.0 == 0
 375     }
 376     pub fn code(&self) -> Option<i32> {
 377         Some(self.0 as i32)
 378     }
 379 }
 380
 381 /// Converts a raw `c::DWORD` to a type-safe `ExitStatus` by wrapping it without copying.
 382 impl From<c::DWORD> for ExitStatus {
 383     fn from(u: c::DWORD) -> ExitStatus {
 384         ExitStatus(u)
 385     }
 386 }
 387
 388 impl fmt::Display for ExitStatus {
 389     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 390         // Windows exit codes with the high bit set typically mean some form of
 391         // unhandled exception or warning. In this scenario printing the exit
 392         // code in decimal doesn't always make sense because it's a very large
 393         // and somewhat gibberish number. The hex code is a bit more
 394         // recognizable and easier to search for, so print that.
 395         if self.0 & 0x80000000 != 0 {
 396             write!(f, "exit code: {:#x}", self.0)
 397         } else {
 398             write!(f, "exit code: {}", self.0)
 399         }
 400     }
 401 }
 402
 403 #[derive(PartialEq, Eq, Clone, Copy, Debug)]
 404 pub struct ExitCode(c::DWORD);
 405
 406 impl ExitCode {
 407     pub const SUCCESS: ExitCode = ExitCode(EXIT_SUCCESS as _);
 408     pub const FAILURE: ExitCode = ExitCode(EXIT_FAILURE as _);
 409
 410     #[inline]
 411     pub fn as_i32(&self) -> i32 {
 412         self.0 as i32
 413     }
 414 }
 415
 416 fn zeroed_startupinfo() -> c::STARTUPINFO {
 417     c::STARTUPINFO {
 418         cb: 0,
 419         lpReserved: ptr::null_mut(),
 420         lpDesktop: ptr::null_mut(),
 421         lpTitle: ptr::null_mut(),
 422         dwX: 0,
 423         dwY: 0,
 424         dwXSize: 0,
 425         dwYSize: 0,
 426         dwXCountChars: 0,
 427         dwYCountCharts: 0,
 428         dwFillAttribute: 0,
 429         dwFlags: 0,
 430         wShowWindow: 0,
 431         cbReserved2: 0,
 432         lpReserved2: ptr::null_mut(),
 433         hStdInput: c::INVALID_HANDLE_VALUE,
 434         hStdOutput: c::INVALID_HANDLE_VALUE,
 435         hStdError: c::INVALID_HANDLE_VALUE,
 436     }
 437 }
 438
 439 fn zeroed_process_information() -> c::PROCESS_INFORMATION {
 440     c::PROCESS_INFORMATION {
 441         hProcess: ptr::null_mut(),
 442         hThread: ptr::null_mut(),
 443         dwProcessId: 0,
 444         dwThreadId: 0,
 445     }
 446 }
 447
 448 // Produces a wide string *without terminating null*; returns an error if
 449 // `prog` or any of the `args` contain a nul.
 450 fn make_command_line(prog: &OsStr, args: &[OsString]) -> io::Result<Vec<u16>> {
 451     // Encode the command and arguments in a command line string such
 452     // that the spawned process may recover them using CommandLineToArgvW.
 453     let mut cmd: Vec<u16> = Vec::new();
 454     // Always quote the program name so CreateProcess doesn't interpret args as
 455     // part of the name if the binary wasn't found first time.
 456     append_arg(&mut cmd, prog, true)?;
 457     for arg in args {
 458         cmd.push(' ' as u16);
 459         append_arg(&mut cmd, arg, false)?;
 460     }
 461     return Ok(cmd);
 462
 463     fn append_arg(cmd: &mut Vec<u16>, arg: &OsStr, force_quotes: bool) -> io::Result<()> {
 464         // If an argument has 0 characters then we need to quote it to ensure
 465         // that it actually gets passed through on the command line or otherwise
 466         // it will be dropped entirely when parsed on the other end.
 467         ensure_no_nuls(arg)?;
 468         let arg_bytes = &arg.as_inner().inner.as_inner();
 469         let quote = force_quotes
 470             || arg_bytes.iter().any(|c| *c == b' ' || *c == b'\t')
 471             || arg_bytes.is_empty();
 472         if quote {
 473             cmd.push('"' as u16);
 474         }
 475
 476         let mut backslashes: usize = 0;
 477         for x in arg.encode_wide() {
 478             if x == '\\' as u16 {
 479                 backslashes += 1;
 480             } else {
 481                 if x == '"' as u16 {
 482                     // Add n+1 backslashes to total 2n+1 before internal '"'.
 483                     cmd.extend((0..=backslashes).map(|_| '\\' as u16));
 484                 }
 485                 backslashes = 0;
 486             }
 487             cmd.push(x);
 488         }
 489
 490         if quote {
 491             // Add n backslashes to total 2n before ending '"'.
 492             cmd.extend((0..backslashes).map(|_| '\\' as u16));
 493             cmd.push('"' as u16);
 494         }
 495         Ok(())
 496     }
 497 }
 498
 499 fn make_envp(maybe_env: Option<BTreeMap<EnvKey, OsString>>) -> io::Result<(*mut c_void, Vec<u16>)> {
 500     // On Windows we pass an "environment block" which is not a char**, but
 501     // rather a concatenation of null-terminated k=v\0 sequences, with a final
 502     // \0 to terminate.
 503     if let Some(env) = maybe_env {
 504         let mut blk = Vec::new();
 505
 506         for (k, v) in env {
 507             blk.extend(ensure_no_nuls(k.0)?.encode_wide());
 508             blk.push('=' as u16);
 509             blk.extend(ensure_no_nuls(v)?.encode_wide());
 510             blk.push(0);
 511         }
 512         blk.push(0);
 513         Ok((blk.as_mut_ptr() as *mut c_void, blk))
 514     } else {
 515         Ok((ptr::null_mut(), Vec::new()))
 516     }
 517 }
 518
 519 fn make_dirp(d: Option<&OsString>) -> io::Result<(*const u16, Vec<u16>)> {
 520     match d {
 521         Some(dir) => {
 522             let mut dir_str: Vec<u16> = ensure_no_nuls(dir)?.encode_wide().collect();
 523             dir_str.push(0);
 524             Ok((dir_str.as_ptr(), dir_str))
 525         }
 526         None => Ok((ptr::null(), Vec::new())),
 527     }
 528 }
 529
 530 #[cfg(test)]
 531 mod tests {
 532     use super::make_command_line;
 533     use crate::ffi::{OsStr, OsString};
 534
 535     #[test]
 536     fn test_make_command_line() {
 537         fn test_wrapper(prog: &str, args: &[&str]) -> String {
 538             let command_line = &make_command_line(
 539                 OsStr::new(prog),
 540                 &args.iter().map(|a| OsString::from(a)).collect::<Vec<OsString>>(),
 541             )
 542             .unwrap();
 543             String::from_utf16(command_line).unwrap()
 544         }
 545
 546         assert_eq!(test_wrapper("prog", &["aaa", "bbb", "ccc"]), "\"prog\" aaa bbb ccc");
 547
 548         assert_eq!(
 549             test_wrapper("C:\\Program Files\\blah\\blah.exe", &["aaa"]),
 550             "\"C:\\Program Files\\blah\\blah.exe\" aaa"
 551         );
 552         assert_eq!(
 553             test_wrapper("C:\\Program Files\\test", &["aa\"bb"]),
 554             "\"C:\\Program Files\\test\" aa\\\"bb"
 555         );
 556         assert_eq!(test_wrapper("echo", &["a b c"]), "\"echo\" \"a b c\"");
 557         assert_eq!(
 558             test_wrapper("echo", &["\" \\\" \\", "\\"]),
 559             "\"echo\" \"\\\" \\\\\\\" \\\\\" \\"
 560         );
 561         assert_eq!(
 562             test_wrapper("\u{03c0}\u{042f}\u{97f3}\u{00e6}\u{221e}", &[]),
 563             "\"\u{03c0}\u{042f}\u{97f3}\u{00e6}\u{221e}\""
 564         );
 565     }
 566 }