1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255
use std::result; use std::error::Error; use std::io; use std::io::Result as IoResult; use std::fs::File; use std::string::FromUtf8Error; use std::fmt; use std::ffi::{OsStr, OsString}; use std::time::Duration; use std::env; use std::rc::Rc; use crate::os_common::{ExitStatus, StandardStream}; use crate::communicate; use self::ChildState::*; pub use self::os::ext as os_ext; pub use self::os::make_pipe; /// Interface to a running subprocess. /// /// `Popen` is the parent's interface to a created subprocess. The /// child process is started in the constructor, so owning a `Popen` /// value indicates that the specified program has been successfully /// launched. To prevent accumulation of zombie processes, the child /// is waited upon when a `Popen` goes out of scope, which can be /// prevented using the [`detach`] method. /// /// Depending on how the subprocess was configured, its input, output, /// and error streams can be connected to the parent and available as /// [`stdin`], [`stdout`], and [`stderr`] public fields. If you need /// to read the output and errors into memory (or provide input as a /// memory slice), use the [`communicate_bytes`] or [`communicate`] /// methods, which guarantee deadlock-free communication with the /// subprocess. /// /// `Popen` instances can be obtained with the [`create`] method, or /// using the [`popen`] method of the [`Exec`] class. Subprocesses /// can be connected into pipes, most easily achieved using using /// [`Exec`]. /// /// [`Exec`]: struct.Exec.html /// [`stdin`]: struct.Popen.html#structfield.stdin /// [`stdout`]: struct.Popen.html#structfield.stdout /// [`stderr`]: struct.Popen.html#structfield.stderr /// [`create`]: struct.Popen.html#method.create /// [`communicate`]: struct.Popen.html#method.communicate /// [`communicate_bytes`]: struct.Popen.html#method.communicate_bytes /// [`detach`]: struct.Popen.html#method.detach #[derive(Debug)] pub struct Popen { /// If `stdin` was specified as `Redirection::Pipe`, this will /// contain a writeble `File` connected to the standard input of /// the child process. pub stdin: Option<File>, /// If `stdout` was specified as `Redirection::Pipe`, this will /// contain a readable `File` connected to the standard output of /// the child process. pub stdout: Option<File>, /// If `stderr` was specified as `Redirection::Pipe`, this will /// contain a readable `File` connected to the standard error of /// the child process. pub stderr: Option<File>, child_state: ChildState, detached: bool, } #[derive(Debug)] enum ChildState { Preparing, // only during construction Running { pid: u32, ext: os::ExtChildState, }, Finished(ExitStatus), } mod fileref { // FileRef: a reference-counted File instance, allowing multiple // references to the same File. If the underlying File is Owned, // it will be closed along with the last FileRef. If unowned // (used for system streams), it will remain open. use std::fs::File; use crate::os_common::Undropped; use std::rc::Rc; use std::ops::Deref; #[derive(Debug)] enum InnerFile { OwnedFile(File), RcFile(Rc<File>), System(Undropped<File>), } #[derive(Debug, Clone)] pub struct FileRef(Rc<InnerFile>); impl FileRef { pub fn from_owned(f: File) -> FileRef { FileRef(Rc::new(InnerFile::OwnedFile(f))) } pub fn from_rc(f: Rc<File>) -> FileRef { FileRef(Rc::new(InnerFile::RcFile(f))) } pub fn from_system(f: Undropped<File>) -> FileRef { FileRef(Rc::new(InnerFile::System(f))) } } impl Deref for FileRef { type Target = File; fn deref(&self) -> &File { match *self.0.deref() { InnerFile::OwnedFile(ref f) => f, InnerFile::RcFile(ref f) => f.deref(), InnerFile::System(ref f) => f.get_ref(), } } } } use self::fileref::FileRef; /// Options for [`Popen::create`]. /// /// When constructing `PopenConfig`, always use the [`Default`] trait, /// such as: /// /// ``` /// # use subprocess::*; /// # let argv = &["true"]; /// Popen::create(argv, PopenConfig { /// stdout: Redirection::Pipe, /// detached: true, /// // ... other fields you want to override ... /// ..Default::default() /// }) /// # .unwrap(); /// ``` /// /// This ensures that fields added later do not break existing code. /// /// An alternative to using `PopenConfig` directly is creating /// processes using [`Exec`], a builder for `Popen`. /// /// [`Popen::create`]: struct.Popen.html#method.create /// [`Exec`]: struct.Exec.html /// [`Default`]: https://doc.rust-lang.org/core/default/trait.Default.html #[derive(Debug)] pub struct PopenConfig { /// How to configure the executed program's standard input. pub stdin: Redirection, /// How to configure the executed program's standard output. pub stdout: Redirection, /// How to configure the executed program's standard error. pub stderr: Redirection, /// Whether the `Popen` instance is initially detached. pub detached: bool, /// Executable to run. /// /// If provided, this executable will be used to run the program /// instead of `argv[0]`. However, `argv[0]` will still be passed /// to the subprocess, which will see that as `argv[0]`. On some /// Unix systems, `ps` will show the string passed as `argv[0]`, /// even though `executable` is actually running. pub executable: Option<OsString>, /// Environment variables to pass to the subprocess. /// /// If this is None, environment variables are inherited from the calling /// process. Otherwise, the specified variables are used instead. /// /// Duplicates are eliminated, with the value taken from the /// variable appearing later in the vector. pub env: Option<Vec<(OsString, OsString)>>, /// Initial current working directory of the subprocess. /// /// None means inherit the working directory from the parent. pub cwd: Option<OsString>, // preexec_fn, close_fds... // force construction using ..Default::default() #[doc(hidden)] pub _use_default_to_construct: (), } impl PopenConfig { /// Clone the underlying [`PopenConfig`], or return an error. /// /// This is guaranteed not to fail as long as no /// [`Redirection::File`] variant is used for one of the standard /// streams. Otherwise, it fails if `File::try_clone` fails on /// one of the `Redirection`s. /// /// [`PopenConfig`]: struct.PopenConfig.html /// [`Redirection::File`]: enum.Redirection.html#variant.File pub fn try_clone(&self) -> IoResult<PopenConfig> { Ok(PopenConfig { stdin: self.stdin.try_clone()?, stdout: self.stdout.try_clone()?, stderr: self.stderr.try_clone()?, detached: self.detached, executable: self.executable.as_ref().cloned(), env: self.env.clone(), cwd: self.cwd.clone(), _use_default_to_construct: (), }) } /// Returns the environment of the current process. /// /// The returned value is in the format accepted by the `env` /// member of `PopenConfig`. pub fn current_env() -> Vec<(OsString, OsString)> { env::vars_os() .map(|(k, v)| (k.to_owned(), v.to_owned())) .collect() } } impl Default for PopenConfig { fn default() -> PopenConfig { PopenConfig { stdin: Redirection::None, stdout: Redirection::None, stderr: Redirection::None, detached: false, executable: None, env: None, cwd: None, _use_default_to_construct: (), } } } /// Instruction what to do with a stream in the child process. /// /// `Redirection` values are used for the `stdin`, `stdout`, and /// `stderr` field of the `PopenConfig` struct. They tell /// `Popen::create` how to set up the standard streams in the child /// process and the corresponding fields of the `Popen` struct in the /// parent. #[derive(Debug)] pub enum Redirection { /// Do nothing with the stream. /// /// The stream is typically inherited from the parent. The field /// in `Popen` corresponding to the stream will be `None`. None, /// Redirect the stream to a pipe. /// /// This variant requests that a stream be redirected to a /// unidirectional pipe. One end of the pipe is passed to the /// child process and configured as one of its standard streams, /// and the other end is available to the parent for communicating /// with the child. /// /// The field with `Popen` corresponding to the stream will be /// `Some(file)`, `File` being the parent's end of the pipe. Pipe, /// Merge the stream to the other output stream. /// /// This variant is only valid when configuring redirection of /// standard output and standard error. Using /// `Redirection::Merge` for `PopenConfig::stderr` requests the /// child's stderr to refer to the same underlying file as the /// child's stdout (which may or may not itself be redirected), /// equivalent to the `2>&1` operator of the Bourne shell. /// Analogously, using `Redirection::Merge` for /// `PopenConfig::stdout` is equivalent to `1>&2` in the shell. /// /// Specifying `Redirection::Merge` for `PopenConfig::stdin` or /// specifying it for both `stdout` and `stderr` is invalid and /// will cause `Popen::create` to return /// `Err(PopenError::LogicError)`. /// /// The field in `Popen` corresponding to the stream will be /// `None`. Merge, /// Redirect the stream to the specified open `File`. /// /// This does not create a pipe, it simply spawns the child so /// that the specified stream sees that file. The child can read /// from or write to the provided file on its own, without any /// intervention by the parent. /// /// The field in `Popen` corresponding to the stream will be /// `None`. File(File), /// Like `File`, but the file is specified as `Rc`. /// /// This allows the same file to be used in multiple redirections. RcFile(Rc<File>), } impl Redirection { /// Clone the underlying `Redirection`, or return an error. /// /// Can fail in `File` variant. pub fn try_clone(&self) -> IoResult<Redirection> { Ok(match *self { Redirection::None => Redirection::None, Redirection::Pipe => Redirection::Pipe, Redirection::Merge => Redirection::Merge, Redirection::File(ref f) => Redirection::File(f.try_clone()?), Redirection::RcFile(ref f) => Redirection::RcFile(f.clone()), }) } } impl Popen { /// Execute an external program in a new process. /// /// `argv` is a slice containing the program followed by its /// arguments, such as `&["ps", "x"]`. `config` specifies details /// how to create and interface to the process. /// /// For example, this launches the `cargo update` command: /// /// ```no_run /// # use subprocess::*; /// # fn dummy() -> Result<()> { /// Popen::create(&["cargo", "update"], PopenConfig::default())?; /// # Ok(()) /// # } /// ``` /// /// # Errors /// /// If the external program cannot be executed for any reason, an /// error is returned. The most typical reason for execution to /// fail is that the program is missing on the `PATH`, but other /// errors are also possible. Note that this is distinct from the /// program running and then exiting with a failure code - this /// can be detected by calling the `wait` method to obtain its /// exit status. pub fn create<S: AsRef<OsStr>>(argv: &[S], config: PopenConfig) -> Result<Popen> { if argv.is_empty() { return Err(PopenError::LogicError("argv must not be empty")); } let argv: Vec<OsString> = argv.iter() .map(|p| p.as_ref().to_owned()).collect(); let mut inst = Popen { stdin: None, stdout: None, stderr: None, child_state: ChildState::Preparing, detached: config.detached, }; inst.os_start(argv, config)?; Ok(inst) } // Create the pipes requested by stdin, stdout, and stderr from // the PopenConfig used to construct us, and return the Files to // be given to the child process. // // For Redirection::Pipe, this stores the parent end of the pipe // to the appropriate self.std* field, and returns the child end // of the pipe. // // For Redirection::File, this transfers the ownership of the File // to the corresponding child. fn setup_streams(&mut self, stdin: Redirection, stdout: Redirection, stderr: Redirection) -> Result<(Option<FileRef>, Option<FileRef>, Option<FileRef>)> { fn prepare_pipe(parent_writes: bool, parent_ref: &mut Option<File>, child_ref: &mut Option<FileRef>) -> Result<()> { // Store the parent's end of the pipe into the given // reference, and store the child end. let (read, write) = os::make_pipe()?; let (parent_end, child_end) = if parent_writes {(write, read)} else {(read, write)}; os::set_inheritable(&parent_end, false)?; *parent_ref = Some(parent_end); *child_ref = Some(FileRef::from_owned(child_end)); Ok(()) } fn prepare_file(file: File, child_ref: &mut Option<FileRef>) -> IoResult<()> { // Make the File inheritable and store it for use in the child. os::set_inheritable(&file, true)?; *child_ref = Some(FileRef::from_owned(file)); Ok(()) } fn prepare_rc_file(file: Rc<File>, child_ref: &mut Option<FileRef>) -> IoResult<()> { // Like prepare_file, but for Rc<File> use std::ops::Deref; os::set_inheritable(file.deref(), true)?; *child_ref = Some(FileRef::from_rc(file)); Ok(()) } fn reuse_stream(dest: &mut Option<FileRef>, src: &mut Option<FileRef>, src_id: StandardStream) -> IoResult<()> { // For Redirection::Merge, make stdout and stderr refer to // the same File. If the file is unavailable, use the // appropriate system output stream. if src.is_none() { *src = Some(FileRef::from_system(os::get_standard_stream(src_id)?)); } *dest = Some(src.as_ref().unwrap().clone()); Ok(()) } enum MergeKind { ErrToOut, // 2>&1 OutToErr, // 1>&2 None, } let mut merge: MergeKind = MergeKind::None; let (mut child_stdin, mut child_stdout, mut child_stderr) = (None, None, None); match stdin { Redirection::Pipe => prepare_pipe(true, &mut self.stdin, &mut child_stdin)?, Redirection::File(file) => prepare_file(file, &mut child_stdin)?, Redirection::RcFile(file) => prepare_rc_file(file, &mut child_stdin)?, Redirection::Merge => { return Err(PopenError::LogicError("Redirection::Merge not valid for stdin")); } Redirection::None => (), }; match stdout { Redirection::Pipe => prepare_pipe(false, &mut self.stdout, &mut child_stdout)?, Redirection::File(file) => prepare_file(file, &mut child_stdout)?, Redirection::RcFile(file) => prepare_rc_file(file, &mut child_stdout)?, Redirection::Merge => merge = MergeKind::OutToErr, Redirection::None => (), }; match stderr { Redirection::Pipe => prepare_pipe(false, &mut self.stderr, &mut child_stderr)?, Redirection::File(file) => prepare_file(file, &mut child_stderr)?, Redirection::RcFile(file) => prepare_rc_file(file, &mut child_stderr)?, Redirection::Merge => merge = MergeKind::ErrToOut, Redirection::None => (), }; // Handle Redirection::Merge after creating the output child // streams. Merge by cloning the child stream, or the // appropriate standard stream if we don't have a child stream // requested using Redirection::Pipe or Redirection::File. In // other words, 2>&1 (ErrToOut) is implemented by making // child_stderr point to a dup of child_stdout, or of the OS's // stdout stream. match merge { MergeKind::ErrToOut => reuse_stream(&mut child_stderr, &mut child_stdout, StandardStream::Output)?, MergeKind::OutToErr => reuse_stream(&mut child_stdout, &mut child_stderr, StandardStream::Error)?, MergeKind::None => (), } Ok((child_stdin, child_stdout, child_stderr)) } /// Mark the process as detached. /// /// This method has no effect on the OS level, it simply tells /// `Popen` not to wait for the subprocess to finish when going /// out of scope. If the child process has already finished, or /// if it is guaranteed to finish before `Popen` goes out of /// scope, calling `detach` has no effect. pub fn detach(&mut self) { self.detached = true; } /// Return the PID of the subprocess, if it is known to be still running. /// /// Note that this method won't actually *check* whether the child /// process is still running, it will only return the information /// last set using one of `create`, `wait`, `wait_timeout`, or /// `poll`. For a newly created `Popen`, `pid()` always returns /// `Some`. pub fn pid(&self) -> Option<u32> { match self.child_state { Running { pid, .. } => Some(pid), _ => None } } /// Return the exit status of the subprocess, if it is known to have finished. /// /// Note that this method won't actually *check* whether the child /// process has finished, it only returns the previously available /// information. To check or wait for the process to finish, call /// `wait`, `wait_timeout`, or `poll`. pub fn exit_status(&self) -> Option<ExitStatus> { match self.child_state { Finished(exit_status) => Some(exit_status), _ => None } } /// Feed and capture the piped data of the subprocess. /// /// This will send the `input_data` to the subprocess, read its /// output and error, and return them as a pair of /// `Option<Vec<u8>>`. The corresponding options will be `None` if /// the respective stream was not specified as `Redirection::Pipe`. /// /// The communication is guaranteed to be deadlock-free. This is /// currently ensured using threads (only when interaction with /// more than one stream is needed), and may be converted to /// `poll()` in the future. /// /// Note that this method will not wait for the program to finish, /// only to close its output stream(s). The program may continue /// running afterwards, and `wait()` must be used to ensure that /// it has actually finished. /// /// # Panics /// /// If `input_data` is provided and `stdin` was not redirected to /// a pipe. pub fn communicate_bytes(&mut self, input_data: Option<&[u8]>) -> IoResult<(Option<Vec<u8>>, Option<Vec<u8>>)> { communicate::communicate(&mut self.stdin, &mut self.stdout, &mut self.stderr, input_data) } /// Feed and capture the piped data of the subprocess as strings. /// /// This is a convenience method equivalent to /// `communicate_bytes`, but with input as `&str` and output as /// `String`. /// /// # Panics /// /// The same as with `communicate_bytes` /// /// # Errors /// /// * `Err(::std::io::Error)` if a system call fails /// * `Err(PopenError::Utf8Error)` if the output of the process is /// not valid UTF-8 and therefore cannot be represented as a /// String. /// /// # Panics /// /// If `input_data` is provided and `stdin` was not redirected to /// a pipe. pub fn communicate(&mut self, input_data: Option<&str>) -> Result<(Option<String>, Option<String>)> { let (out, err) = self.communicate_bytes( input_data.map(|s| s.as_bytes()))?; let out_str = if let Some(out_vec) = out { Some(String::from_utf8(out_vec)?) } else { None }; let err_str = if let Some(err_vec) = err { Some(String::from_utf8(err_vec)?) } else { None }; Ok((out_str, err_str)) } /// Check whether the process is still running, without blocking or errors. /// /// This checks whether the process is still running and if it /// is still running, `None` is returned, otherwise /// `Some(exit_status)`. This method is guaranteed not to block /// and is exactly equivalent to /// `wait_timeout(Duration::new(0, 0)).unwrap_or(None)`. pub fn poll(&mut self) -> Option<ExitStatus> { self.wait_timeout(Duration::from_secs(0)).unwrap_or(None) } /// Wait for the process to finish, and return its exit status. /// /// If the process has already finished, it will exit immediately, /// returning the exit status. Calling `wait` after that will /// return the cached exit status without executing any system /// calls. /// /// # Errors /// /// Returns an `Err` if a system call fails in an unpredicted way. /// This should not happen in normal usage. pub fn wait(&mut self) -> Result<ExitStatus> { self.os_wait() } /// Wait for the process to finish, timing out after the specified duration. /// /// This function behaves like `wait()`, except that the caller /// will be blocked for roughly no longer than `dur`. It returns /// `Ok(None)` if the timeout is known to have elapsed. /// /// On Unix-like systems, timeout is implemented by calling /// `waitpid(..., WNOHANG)` in a loop with adaptive sleep /// intervals between iterations. pub fn wait_timeout(&mut self, dur: Duration) -> Result<Option<ExitStatus>> { self.os_wait_timeout(dur) } /// Terminate the subprocess. /// /// On Unix-like systems, this sends the `SIGTERM` signal to the /// child process, which can be caught by the child in order to /// perform cleanup before exiting. On Windows, it is equivalent /// to `kill()`. pub fn terminate(&mut self) -> IoResult<()> { self.os_terminate() } /// Kill the subprocess. /// /// On Unix-like systems, this sends the `SIGKILL` signal to the /// child process, which cannot be caught. /// /// On Windows, it invokes [`TerminateProcess`] on the process /// handle with equivalent semantics. /// /// [`TerminateProcess`]: https://msdn.microsoft.com/en-us/library/windows/desktop/ms686714(v=vs.85).aspx pub fn kill(&mut self) -> IoResult<()> { self.os_kill() } } trait PopenOs { fn os_start(&mut self, argv: Vec<OsString>, config: PopenConfig) -> Result<()>; fn os_wait(&mut self) -> Result<ExitStatus>; fn os_wait_timeout(&mut self, dur: Duration) -> Result<Option<ExitStatus>>; fn os_terminate(&mut self) -> IoResult<()>; fn os_kill(&mut self) -> IoResult<()>; } #[cfg(unix)] mod os { use super::*; use std::io; use std::io::{Read, Write, Result as IoResult}; use std::fs::File; use crate::posix; use std::mem; use std::os::unix::io::AsRawFd; use std::ffi::OsString; use std::time::{Duration, Instant}; use std::collections::HashSet; use crate::os_common::ExitStatus; use crate::unix::PopenExt; pub type ExtChildState = (); impl super::PopenOs for Popen { fn os_start(&mut self, argv: Vec<OsString>, config: PopenConfig) -> Result<()> { let mut exec_fail_pipe = posix::pipe()?; set_inheritable(&exec_fail_pipe.0, false)?; set_inheritable(&exec_fail_pipe.1, false)?; { let child_ends = self.setup_streams(config.stdin, config.stdout, config.stderr)?; let child_env = config.env.map(format_env); let cmd_to_exec = config.executable.as_ref().unwrap_or(&argv[0]); let just_exec = posix::stage_exec(cmd_to_exec, &argv[..], child_env.as_ref().map(::std::ops::Deref::deref))?; unsafe { // unsafe because after the call to fork() the // child is not allowed to allocate match posix::fork()? { Some(child_pid) => { self.child_state = Running { pid: child_pid, ext: () }; } None => { mem::drop(exec_fail_pipe.0); let result = self.do_exec(just_exec, child_ends, config.cwd.as_ref().map(|x| &x[..])); // If we are here, it means that exec has failed. Notify // the parent and exit. let error_code = match result { Ok(()) => unreachable!(), Err(e) => e.raw_os_error().unwrap_or(-1) } as u32; exec_fail_pipe.1.write_all( &[error_code as u8, (error_code >> 8) as u8, (error_code >> 16) as u8, (error_code >> 24) as u8]).ok(); posix::_exit(127); } } } } mem::drop(exec_fail_pipe.1); let mut error_buf = [0u8; 4]; let read_cnt = exec_fail_pipe.0.read(&mut error_buf)?; if read_cnt == 0 { Ok(()) } else if read_cnt == 4 { let error_code: u32 = error_buf[0] as u32 | (error_buf[1] as u32) << 8 | (error_buf[2] as u32) << 16 | (error_buf[3] as u32) << 24; Err(PopenError::from(io::Error::from_raw_os_error(error_code as i32))) } else { Err(PopenError::LogicError("invalid read_count from exec pipe")) } } fn os_wait(&mut self) -> Result<ExitStatus> { while let Running {..} = self.child_state { self.waitpid(true)?; } Ok(self.exit_status().unwrap()) } fn os_wait_timeout(&mut self, dur: Duration) -> Result<Option<ExitStatus>> { use std::cmp::min; if let Finished(exit_status) = self.child_state { return Ok(Some(exit_status)); } let deadline = Instant::now() + dur; // double delay at every iteration, maxing at 100ms let mut delay = Duration::from_millis(1); loop { self.waitpid(false)?; if let Finished(exit_status) = self.child_state { return Ok(Some(exit_status)); } let now = Instant::now(); if now >= deadline { return Ok(None); } let remaining = deadline.duration_since(now); ::std::thread::sleep(min(delay, remaining)); delay = min(delay * 2, Duration::from_millis(100)); } } fn os_terminate(&mut self) -> IoResult<()> { self.send_signal(posix::SIGTERM) } fn os_kill(&mut self) -> IoResult<()> { self.send_signal(posix::SIGKILL) } } fn format_env(env: Vec<(OsString, OsString)>) -> Vec<OsString> { // Convert Vec of (key, val) pairs to Vec of key=val, as // required by execvpe. Also eliminate dups, with the // later-appearing one taking precedence. let mut seen = HashSet::<OsString>::new(); let mut formatted: Vec<_> = env.into_iter().rev() .filter(|&(ref k, ref _v)| seen.insert(k.clone())) .map(|(ref k, ref v)| { let mut fmt = k.clone(); fmt.push("="); fmt.push(v); fmt }).collect(); formatted.reverse(); formatted } trait PopenOsImpl: super::PopenOs { fn do_exec(&self, just_exec: impl Fn() -> IoResult<()>, child_ends: (Option<FileRef>, Option<FileRef>, Option<FileRef>), cwd: Option<&OsStr>) -> IoResult<()>; fn waitpid(&mut self, block: bool) -> IoResult<()>; } impl PopenOsImpl for Popen { fn do_exec(&self, just_exec: impl Fn() -> IoResult<()>, child_ends: (Option<FileRef>, Option<FileRef>, Option<FileRef>), cwd: Option<&OsStr>) -> IoResult<()> { if let Some(cwd) = cwd { env::set_current_dir(cwd)?; } let (stdin, stdout, stderr) = child_ends; if let Some(stdin) = stdin { if stdin.as_raw_fd() != 0 { posix::dup2(stdin.as_raw_fd(), 0)?; } } if let Some(stdout) = stdout { if stdout.as_raw_fd() != 1 { posix::dup2(stdout.as_raw_fd(), 1)?; } } if let Some(stderr) = stderr { if stderr.as_raw_fd() != 2 { posix::dup2(stderr.as_raw_fd(), 2)?; } } posix::reset_sigpipe()?; just_exec()?; unreachable!(); } fn waitpid(&mut self, block: bool) -> IoResult<()> { match self.child_state { Preparing => panic!("child_state == Preparing"), Running { pid, .. } => { match posix::waitpid(pid, if block { 0 } else { posix::WNOHANG }) { Err(e) => { if let Some(errno) = e.raw_os_error() { if errno == posix::ECHILD { // Someone else has waited for the child // (another thread, a signal handler...). // The PID no longer exists and we cannot // find its exit status. self.child_state = Finished(ExitStatus::Undetermined); return Ok(()); } } return Err(e); } Ok((pid_out, exit_status)) => { if pid_out == pid { self.child_state = Finished(exit_status); } } } }, Finished(..) => (), } Ok(()) } } pub fn set_inheritable(f: &File, inheritable: bool) -> IoResult<()> { if inheritable { // Unix pipes are inheritable by default. } else { let fd = f.as_raw_fd(); let old = posix::fcntl(fd, posix::F_GETFD, None)?; posix::fcntl(fd, posix::F_SETFD, Some(old | posix::FD_CLOEXEC))?; } Ok(()) } /// Create a pipe. /// /// This is a safe wrapper over `libc::pipe` or /// `winapi::um::namedpipeapi::CreatePipe`, depending on the operating /// system. pub fn make_pipe() -> IoResult<(File, File)> { posix::pipe() } pub use posix::get_standard_stream; pub mod ext { use std::io::Result as IoResult; use crate::popen::Popen; use crate::popen::ChildState::*; use crate::posix; /// Unix-specific extension methods for `Popen` pub trait PopenExt { /// Send the specified signal to the child process. /// /// The signal numbers are best obtained from the [`libc`] /// crate. /// /// If the child process is known to have finished (due to e.g. /// a previous call to [`wait`] or [`poll`]), this will do /// nothing and return `Ok`. /// /// [`poll`]: ../struct.Popen.html#method.poll /// [`wait`]: ../struct.Popen.html#method.wait /// [`libc`]: https://docs.rs/libc/ fn send_signal(&self, signal: i32) -> IoResult<()>; } impl PopenExt for Popen { fn send_signal(&self, signal: i32) -> IoResult<()> { match self.child_state { Preparing => panic!("child_state == Preparing"), Running { pid, .. } => { posix::kill(pid, signal) }, Finished(..) => Ok(()), } } } } } #[cfg(windows)] mod os { use super::*; use std::io; use std::fs::{self, File}; use std::env; use std::ffi::{OsStr, OsString}; use std::os::windows::ffi::{OsStrExt, OsStringExt}; use std::os::windows::io::{RawHandle, AsRawHandle}; use std::time::Duration; use std::io::Result as IoResult; use std::collections::HashSet; use crate::win32; use crate::os_common::{ExitStatus, StandardStream}; #[derive(Debug)] pub struct ExtChildState(win32::Handle); impl super::PopenOs for Popen { fn os_start(&mut self, argv: Vec<OsString>, config: PopenConfig) -> Result<()> { fn raw(opt: &Option<FileRef>) -> Option<RawHandle> { opt.as_ref().map(|f| f.as_raw_handle()) } let (mut child_stdin, mut child_stdout, mut child_stderr) = self.setup_streams(config.stdin, config.stdout, config.stderr)?; ensure_child_stream(&mut child_stdin, StandardStream::Input)?; ensure_child_stream(&mut child_stdout, StandardStream::Output)?; ensure_child_stream(&mut child_stderr, StandardStream::Error)?; let cmdline = assemble_cmdline(argv)?; let env_block = config.env.map(format_env_block); // CreateProcess doesn't search for appname in the PATH. // We do it ourselves to match the Unix behavior. let executable = config.executable.map(locate_in_path); let (handle, pid) = win32::CreateProcess(executable.as_ref().map(OsString::as_ref), &cmdline, &env_block, &config.cwd.as_ref().map(|os| &os[..]), true, 0, raw(&child_stdin), raw(&child_stdout), raw(&child_stderr), win32::STARTF_USESTDHANDLES)?; self.child_state = Running { pid: pid as u32, ext: ExtChildState(handle) }; Ok(()) } fn os_wait(&mut self) -> Result<ExitStatus> { self.wait_handle(None)?; match self.child_state { Preparing => panic!("child_state == Preparing"), Finished(exit_status) => Ok(exit_status), // Since we invoked wait_handle without timeout, exit // status should exist at this point. The only way // for it not to exist would be if something strange // happened, like WaitForSingleObject returning // something other than OBJECT_0. Running {..} => Err( PopenError::LogicError("Failed to obtain exit status")) } } fn os_wait_timeout(&mut self, dur: Duration) -> Result<Option<ExitStatus>> { if let Finished(exit_status) = self.child_state { return Ok(Some(exit_status)); } self.wait_handle(Some(dur))?; Ok(self.exit_status()) } fn os_terminate(&mut self) -> IoResult<()> { let mut new_child_state = None; if let Running { ext: ExtChildState(ref handle), .. } = self.child_state { match win32::TerminateProcess(handle, 1) { Err(err) => { if err.raw_os_error() != Some(win32::ERROR_ACCESS_DENIED as i32) { return Err(err); } let rc = win32::GetExitCodeProcess(handle)?; if rc == win32::STILL_ACTIVE { return Err(err); } new_child_state = Some(Finished(ExitStatus::Exited(rc))); } Ok(_) => () } } if let Some(new_child_state) = new_child_state { self.child_state = new_child_state; } Ok(()) } fn os_kill(&mut self) -> IoResult<()> { self.terminate() } } fn format_env_block(env: Vec<(OsString, OsString)>) -> Vec<u16> { fn to_uppercase(s: &OsStr) -> OsString { OsString::from_wide(&s.encode_wide() .map(|c| if c < 128 { (c as u8 as char).to_ascii_uppercase() as u16 } else { c }).collect::<Vec<u16>>()) } let mut pruned = { let mut seen = HashSet::<OsString>::new(); env.into_iter().rev() .filter(|&(ref k, ref _v)| seen.insert(to_uppercase(&k))) .collect::<Vec<_>>() }; pruned.reverse(); let mut block = Vec::<u16>::new(); for (k, v) in pruned { block.extend(k.encode_wide()); block.push('=' as u16); block.extend(v.encode_wide()); block.push(0); } block.push(0); block } trait PopenOsImpl: super::PopenOs { fn wait_handle(&mut self, timeout: Option<Duration>) -> IoResult<Option<ExitStatus>>; } impl PopenOsImpl for Popen { fn wait_handle(&mut self, timeout: Option<Duration>) -> IoResult<Option<ExitStatus>> { let mut new_child_state = None; if let Running { ext: ExtChildState(ref handle), .. } = self.child_state { let millis = timeout.map(|t| { if t <= Duration::new(4294967, 295_000_000) { (t.as_secs() as u32 * 1_000 + t.subsec_nanos() / 1_000_000) } else { // Clamp to avoid overflow. We could support timeouts // longer than 49.71 days with multiple waits. u32::max_value() } }); let event = win32::WaitForSingleObject(handle, millis)?; if let win32::WaitEvent::OBJECT_0 = event { let exit_code = win32::GetExitCodeProcess(handle)?; new_child_state = Some(Finished(ExitStatus::Exited(exit_code))); } } if let Some(new_child_state) = new_child_state { self.child_state = new_child_state; } Ok(self.exit_status()) } } fn ensure_child_stream(stream: &mut Option<FileRef>, which: StandardStream) -> IoResult<()> { // If no stream is sent to CreateProcess, the child doesn't // get a valid stream. This results in e.g. // Exec("sh").arg("-c").arg("echo foo >&2").stream_stderr() // failing because the shell tries to redirect stdout to // stderr, but fails because it didn't receive a valid stdout. if stream.is_none() { *stream = Some(FileRef::from_system(get_standard_stream(which)?)); } Ok(()) } pub fn set_inheritable(f: &File, inheritable: bool) -> IoResult<()> { win32::SetHandleInformation(f, win32::HANDLE_FLAG_INHERIT, if inheritable {1} else {0})?; Ok(()) } /// Create a pipe. /// /// This is a safe wrapper over `libc::pipe` or /// `winapi::um::namedpipeapi::CreatePipe`, depending on the operating /// system. pub fn make_pipe() -> IoResult<(File, File)> { win32::CreatePipe(true) } fn locate_in_path(executable: OsString) -> OsString { if let Some(path) = env::var_os("PATH") { for path in env::split_paths(&path) { let path = path.join(&executable) .with_extension(::std::env::consts::EXE_EXTENSION); if fs::metadata(&path).is_ok() { return path.into_os_string(); } } } executable } fn assemble_cmdline(argv: Vec<OsString>) -> IoResult<OsString> { let mut cmdline = Vec::<u16>::new(); let mut is_first = true; for arg in argv { if !is_first { cmdline.push(' ' as u16); } else { is_first = false; } if arg.encode_wide().any(|c| c == 0) { return Err(io::Error::from_raw_os_error( win32::ERROR_BAD_PATHNAME as i32)); } append_quoted(&arg, &mut cmdline); } Ok(OsString::from_wide(&cmdline)) } // Translated from ArgvQuote at http://tinyurl.com/zmgtnls fn append_quoted(arg: &OsStr, cmdline: &mut Vec<u16>) { if !arg.is_empty() && !arg.encode_wide().any( |c| c == ' ' as u16 || c == '\t' as u16 || c == '\n' as u16 || c == '\x0b' as u16 || c == '\"' as u16) { cmdline.extend(arg.encode_wide()); return } cmdline.push('"' as u16); let arg: Vec<_> = arg.encode_wide().collect(); let mut i = 0; while i < arg.len() { let mut num_backslashes = 0; while i < arg.len() && arg[i] == '\\' as u16 { i += 1; num_backslashes += 1; } if i == arg.len() { for _ in 0..num_backslashes*2 { cmdline.push('\\' as u16); } break; } else if arg[i] == b'"' as u16 { for _ in 0..num_backslashes*2 + 1 { cmdline.push('\\' as u16); } cmdline.push(arg[i]); } else { for _ in 0..num_backslashes { cmdline.push('\\' as u16); } cmdline.push(arg[i]); } i += 1; } cmdline.push('"' as u16); } pub use win32::get_standard_stream; pub mod ext {} } impl Drop for Popen { // Wait for the process to exit. To avoid the wait, call // detach(). fn drop(&mut self) { if let (false, &Running {..}) = (self.detached, &self.child_state) { // Should we log error if one occurs during drop()? self.wait().ok(); } } } /// Error in [`Popen`] calls. /// /// [`Popen`]: struct.Popen.html #[derive(Debug)] pub enum PopenError { /// Error when attempting to convert bytes to string. Utf8Error(FromUtf8Error), /// The underlying error is io::Error. IoError(io::Error), /// A logical error was made, e.g. invalid arguments detected at run-time. LogicError(&'static str), } impl From<FromUtf8Error> for PopenError { fn from(err: FromUtf8Error) -> PopenError { PopenError::Utf8Error(err) } } impl From<io::Error> for PopenError { fn from(err: io::Error) -> PopenError { PopenError::IoError(err) } } impl Error for PopenError { fn description(&self) -> &str { match *self { PopenError::Utf8Error(ref err) => err.description(), PopenError::IoError(ref err) => err.description(), PopenError::LogicError(description) => description, } } fn cause(&self) -> Option<&dyn Error> { match *self { PopenError::Utf8Error(ref err) => Some(err as &dyn Error), PopenError::IoError(ref err) => Some(err as &dyn Error), PopenError::LogicError(_) => None, } } } impl fmt::Display for PopenError { fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { match *self { PopenError::Utf8Error(ref err) => fmt::Display::fmt(err, f), PopenError::IoError(ref err) => fmt::Display::fmt(err, f), PopenError::LogicError(desc) => f.write_str(desc) } } } /// Result returned by calls in the `subprocess` crate in places where /// `::std::io::Result` does not suffice. pub type Result<T> = result::Result<T, PopenError>;