std/sys/process/unix/
common.rs

1#[cfg(all(test, not(target_os = "emscripten")))]
2mod tests;
3
4use libc::{EXIT_FAILURE, EXIT_SUCCESS, c_int, gid_t, pid_t, uid_t};
5
6pub use self::cstring_array::CStringArray;
7use self::cstring_array::CStringIter;
8use crate::collections::BTreeMap;
9use crate::ffi::{CStr, CString, OsStr, OsString};
10use crate::os::unix::prelude::*;
11use crate::path::Path;
12use crate::sys::fd::FileDesc;
13use crate::sys::fs::File;
14#[cfg(not(target_os = "fuchsia"))]
15use crate::sys::fs::OpenOptions;
16use crate::sys::pipe::{self, AnonPipe};
17use crate::sys::process::env::{CommandEnv, CommandEnvs};
18use crate::sys_common::{FromInner, IntoInner};
19use crate::{fmt, io};
20
21mod cstring_array;
22
23cfg_select! {
24    target_os = "fuchsia" => {
25        // fuchsia doesn't have /dev/null
26    }
27    target_os = "vxworks" => {
28        const DEV_NULL: &CStr = c"/null";
29    }
30    _ => {
31        const DEV_NULL: &CStr = c"/dev/null";
32    }
33}
34
35// Android with api less than 21 define sig* functions inline, so it is not
36// available for dynamic link. Implementing sigemptyset and sigaddset allow us
37// to support older Android version (independent of libc version).
38// The following implementations are based on
39// https://github.com/aosp-mirror/platform_bionic/blob/ad8dcd6023294b646e5a8288c0ed431b0845da49/libc/include/android/legacy_signal_inlines.h
40cfg_select! {
41    target_os = "android" => {
42        #[allow(dead_code)]
43        pub unsafe fn sigemptyset(set: *mut libc::sigset_t) -> libc::c_int {
44            set.write_bytes(0u8, 1);
45            return 0;
46        }
47
48        #[allow(dead_code)]
49        pub unsafe fn sigaddset(set: *mut libc::sigset_t, signum: libc::c_int) -> libc::c_int {
50            use crate::slice;
51            use libc::{c_ulong, sigset_t};
52
53            // The implementations from bionic (android libc) type pun `sigset_t` as an
54            // array of `c_ulong`. This works, but lets add a smoke check to make sure
55            // that doesn't change.
56            const _: () = assert!(
57                align_of::<c_ulong>() == align_of::<sigset_t>()
58                    && (size_of::<sigset_t>() % size_of::<c_ulong>()) == 0
59            );
60
61            let bit = (signum - 1) as usize;
62            if set.is_null() || bit >= (8 * size_of::<sigset_t>()) {
63                crate::sys::pal::os::set_errno(libc::EINVAL);
64                return -1;
65            }
66            let raw = slice::from_raw_parts_mut(
67                set as *mut c_ulong,
68                size_of::<sigset_t>() / size_of::<c_ulong>(),
69            );
70            const LONG_BIT: usize = size_of::<c_ulong>() * 8;
71            raw[bit / LONG_BIT] |= 1 << (bit % LONG_BIT);
72            return 0;
73        }
74    }
75    _ => {
76        #[allow(unused_imports)]
77        pub use libc::{sigemptyset, sigaddset};
78    }
79}
80
81////////////////////////////////////////////////////////////////////////////////
82// Command
83////////////////////////////////////////////////////////////////////////////////
84
85pub struct Command {
86    program: CString,
87    args: CStringArray,
88    env: CommandEnv,
89
90    program_kind: ProgramKind,
91    cwd: Option<CString>,
92    chroot: Option<CString>,
93    uid: Option<uid_t>,
94    gid: Option<gid_t>,
95    saw_nul: bool,
96    closures: Vec<Box<dyn FnMut() -> io::Result<()> + Send + Sync>>,
97    groups: Option<Box<[gid_t]>>,
98    stdin: Option<Stdio>,
99    stdout: Option<Stdio>,
100    stderr: Option<Stdio>,
101    #[cfg(target_os = "linux")]
102    create_pidfd: bool,
103    pgroup: Option<pid_t>,
104    setsid: bool,
105}
106
107// passed back to std::process with the pipes connected to the child, if any
108// were requested
109pub struct StdioPipes {
110    pub stdin: Option<AnonPipe>,
111    pub stdout: Option<AnonPipe>,
112    pub stderr: Option<AnonPipe>,
113}
114
115// passed to do_exec() with configuration of what the child stdio should look
116// like
117#[cfg_attr(target_os = "vita", allow(dead_code))]
118pub struct ChildPipes {
119    pub stdin: ChildStdio,
120    pub stdout: ChildStdio,
121    pub stderr: ChildStdio,
122}
123
124pub enum ChildStdio {
125    Inherit,
126    Explicit(c_int),
127    Owned(FileDesc),
128
129    // On Fuchsia, null stdio is the default, so we simply don't specify
130    // any actions at the time of spawning.
131    #[cfg(target_os = "fuchsia")]
132    Null,
133}
134
135#[derive(Debug)]
136pub enum Stdio {
137    Inherit,
138    Null,
139    MakePipe,
140    Fd(FileDesc),
141    StaticFd(BorrowedFd<'static>),
142}
143
144#[derive(Copy, Clone, Debug, Eq, PartialEq)]
145pub enum ProgramKind {
146    /// A program that would be looked up on the PATH (e.g. `ls`)
147    PathLookup,
148    /// A relative path (e.g. `my-dir/foo`, `../foo`, `./foo`)
149    Relative,
150    /// An absolute path.
151    Absolute,
152}
153
154impl ProgramKind {
155    fn new(program: &OsStr) -> Self {
156        if program.as_encoded_bytes().starts_with(b"/") {
157            Self::Absolute
158        } else if program.as_encoded_bytes().contains(&b'/') {
159            // If the program has more than one component in it, it is a relative path.
160            Self::Relative
161        } else {
162            Self::PathLookup
163        }
164    }
165}
166
167impl Command {
168    pub fn new(program: &OsStr) -> Command {
169        let mut saw_nul = false;
170        let program_kind = ProgramKind::new(program.as_ref());
171        let program = os2c(program, &mut saw_nul);
172        let mut args = CStringArray::with_capacity(1);
173        args.push(program.clone());
174        Command {
175            program,
176            args,
177            env: Default::default(),
178            program_kind,
179            cwd: None,
180            chroot: None,
181            uid: None,
182            gid: None,
183            saw_nul,
184            closures: Vec::new(),
185            groups: None,
186            stdin: None,
187            stdout: None,
188            stderr: None,
189            #[cfg(target_os = "linux")]
190            create_pidfd: false,
191            pgroup: None,
192            setsid: false,
193        }
194    }
195
196    pub fn set_arg_0(&mut self, arg: &OsStr) {
197        // Set a new arg0
198        let arg = os2c(arg, &mut self.saw_nul);
199        self.args.write(0, arg);
200    }
201
202    pub fn arg(&mut self, arg: &OsStr) {
203        let arg = os2c(arg, &mut self.saw_nul);
204        self.args.push(arg);
205    }
206
207    pub fn cwd(&mut self, dir: &OsStr) {
208        self.cwd = Some(os2c(dir, &mut self.saw_nul));
209    }
210    pub fn uid(&mut self, id: uid_t) {
211        self.uid = Some(id);
212    }
213    pub fn gid(&mut self, id: gid_t) {
214        self.gid = Some(id);
215    }
216    pub fn groups(&mut self, groups: &[gid_t]) {
217        self.groups = Some(Box::from(groups));
218    }
219    pub fn pgroup(&mut self, pgroup: pid_t) {
220        self.pgroup = Some(pgroup);
221    }
222    pub fn chroot(&mut self, dir: &Path) {
223        self.chroot = Some(os2c(dir.as_os_str(), &mut self.saw_nul));
224        if self.cwd.is_none() {
225            self.cwd(&OsStr::new("/"));
226        }
227    }
228    pub fn setsid(&mut self, setsid: bool) {
229        self.setsid = setsid;
230    }
231
232    #[cfg(target_os = "linux")]
233    pub fn create_pidfd(&mut self, val: bool) {
234        self.create_pidfd = val;
235    }
236
237    #[cfg(not(target_os = "linux"))]
238    #[allow(dead_code)]
239    pub fn get_create_pidfd(&self) -> bool {
240        false
241    }
242
243    #[cfg(target_os = "linux")]
244    pub fn get_create_pidfd(&self) -> bool {
245        self.create_pidfd
246    }
247
248    pub fn saw_nul(&self) -> bool {
249        self.saw_nul
250    }
251
252    pub fn get_program(&self) -> &OsStr {
253        OsStr::from_bytes(self.program.as_bytes())
254    }
255
256    #[allow(dead_code)]
257    pub fn get_program_kind(&self) -> ProgramKind {
258        self.program_kind
259    }
260
261    pub fn get_args(&self) -> CommandArgs<'_> {
262        let mut iter = self.args.iter();
263        // argv[0] contains the program name, but we are only interested in the
264        // arguments so skip it.
265        iter.next();
266        CommandArgs { iter }
267    }
268
269    pub fn get_envs(&self) -> CommandEnvs<'_> {
270        self.env.iter()
271    }
272
273    pub fn get_current_dir(&self) -> Option<&Path> {
274        self.cwd.as_ref().map(|cs| Path::new(OsStr::from_bytes(cs.as_bytes())))
275    }
276
277    pub fn get_argv(&self) -> &CStringArray {
278        &self.args
279    }
280
281    pub fn get_program_cstr(&self) -> &CStr {
282        &self.program
283    }
284
285    #[allow(dead_code)]
286    pub fn get_cwd(&self) -> Option<&CStr> {
287        self.cwd.as_deref()
288    }
289    #[allow(dead_code)]
290    pub fn get_uid(&self) -> Option<uid_t> {
291        self.uid
292    }
293    #[allow(dead_code)]
294    pub fn get_gid(&self) -> Option<gid_t> {
295        self.gid
296    }
297    #[allow(dead_code)]
298    pub fn get_groups(&self) -> Option<&[gid_t]> {
299        self.groups.as_deref()
300    }
301    #[allow(dead_code)]
302    pub fn get_pgroup(&self) -> Option<pid_t> {
303        self.pgroup
304    }
305    #[allow(dead_code)]
306    pub fn get_chroot(&self) -> Option<&CStr> {
307        self.chroot.as_deref()
308    }
309    #[allow(dead_code)]
310    pub fn get_setsid(&self) -> bool {
311        self.setsid
312    }
313
314    pub fn get_closures(&mut self) -> &mut Vec<Box<dyn FnMut() -> io::Result<()> + Send + Sync>> {
315        &mut self.closures
316    }
317
318    pub unsafe fn pre_exec(&mut self, f: Box<dyn FnMut() -> io::Result<()> + Send + Sync>) {
319        self.closures.push(f);
320    }
321
322    pub fn stdin(&mut self, stdin: Stdio) {
323        self.stdin = Some(stdin);
324    }
325
326    pub fn stdout(&mut self, stdout: Stdio) {
327        self.stdout = Some(stdout);
328    }
329
330    pub fn stderr(&mut self, stderr: Stdio) {
331        self.stderr = Some(stderr);
332    }
333
334    pub fn env_mut(&mut self) -> &mut CommandEnv {
335        &mut self.env
336    }
337
338    pub fn capture_env(&mut self) -> Option<CStringArray> {
339        let maybe_env = self.env.capture_if_changed();
340        maybe_env.map(|env| construct_envp(env, &mut self.saw_nul))
341    }
342
343    #[allow(dead_code)]
344    pub fn env_saw_path(&self) -> bool {
345        self.env.have_changed_path()
346    }
347
348    #[allow(dead_code)]
349    pub fn program_is_path(&self) -> bool {
350        self.program.to_bytes().contains(&b'/')
351    }
352
353    pub fn setup_io(
354        &self,
355        default: Stdio,
356        needs_stdin: bool,
357    ) -> io::Result<(StdioPipes, ChildPipes)> {
358        let null = Stdio::Null;
359        let default_stdin = if needs_stdin { &default } else { &null };
360        let stdin = self.stdin.as_ref().unwrap_or(default_stdin);
361        let stdout = self.stdout.as_ref().unwrap_or(&default);
362        let stderr = self.stderr.as_ref().unwrap_or(&default);
363        let (their_stdin, our_stdin) = stdin.to_child_stdio(true)?;
364        let (their_stdout, our_stdout) = stdout.to_child_stdio(false)?;
365        let (their_stderr, our_stderr) = stderr.to_child_stdio(false)?;
366        let ours = StdioPipes { stdin: our_stdin, stdout: our_stdout, stderr: our_stderr };
367        let theirs = ChildPipes { stdin: their_stdin, stdout: their_stdout, stderr: their_stderr };
368        Ok((ours, theirs))
369    }
370}
371
372fn os2c(s: &OsStr, saw_nul: &mut bool) -> CString {
373    CString::new(s.as_bytes()).unwrap_or_else(|_e| {
374        *saw_nul = true;
375        c"<string-with-nul>".to_owned()
376    })
377}
378
379fn construct_envp(env: BTreeMap<OsString, OsString>, saw_nul: &mut bool) -> CStringArray {
380    let mut result = CStringArray::with_capacity(env.len());
381    for (mut k, v) in env {
382        // Reserve additional space for '=' and null terminator
383        k.reserve_exact(v.len() + 2);
384        k.push("=");
385        k.push(&v);
386
387        // Add the new entry into the array
388        if let Ok(item) = CString::new(k.into_vec()) {
389            result.push(item);
390        } else {
391            *saw_nul = true;
392        }
393    }
394
395    result
396}
397
398impl Stdio {
399    pub fn to_child_stdio(&self, readable: bool) -> io::Result<(ChildStdio, Option<AnonPipe>)> {
400        match *self {
401            Stdio::Inherit => Ok((ChildStdio::Inherit, None)),
402
403            // Make sure that the source descriptors are not an stdio
404            // descriptor, otherwise the order which we set the child's
405            // descriptors may blow away a descriptor which we are hoping to
406            // save. For example, suppose we want the child's stderr to be the
407            // parent's stdout, and the child's stdout to be the parent's
408            // stderr. No matter which we dup first, the second will get
409            // overwritten prematurely.
410            Stdio::Fd(ref fd) => {
411                if fd.as_raw_fd() >= 0 && fd.as_raw_fd() <= libc::STDERR_FILENO {
412                    Ok((ChildStdio::Owned(fd.duplicate()?), None))
413                } else {
414                    Ok((ChildStdio::Explicit(fd.as_raw_fd()), None))
415                }
416            }
417
418            Stdio::StaticFd(fd) => {
419                let fd = FileDesc::from_inner(fd.try_clone_to_owned()?);
420                Ok((ChildStdio::Owned(fd), None))
421            }
422
423            Stdio::MakePipe => {
424                let (reader, writer) = pipe::anon_pipe()?;
425                let (ours, theirs) = if readable { (writer, reader) } else { (reader, writer) };
426                Ok((ChildStdio::Owned(theirs.into_inner()), Some(ours)))
427            }
428
429            #[cfg(not(target_os = "fuchsia"))]
430            Stdio::Null => {
431                let mut opts = OpenOptions::new();
432                opts.read(readable);
433                opts.write(!readable);
434                let fd = File::open_c(DEV_NULL, &opts)?;
435                Ok((ChildStdio::Owned(fd.into_inner()), None))
436            }
437
438            #[cfg(target_os = "fuchsia")]
439            Stdio::Null => Ok((ChildStdio::Null, None)),
440        }
441    }
442}
443
444impl From<AnonPipe> for Stdio {
445    fn from(pipe: AnonPipe) -> Stdio {
446        Stdio::Fd(pipe.into_inner())
447    }
448}
449
450impl From<FileDesc> for Stdio {
451    fn from(fd: FileDesc) -> Stdio {
452        Stdio::Fd(fd)
453    }
454}
455
456impl From<File> for Stdio {
457    fn from(file: File) -> Stdio {
458        Stdio::Fd(file.into_inner())
459    }
460}
461
462impl From<io::Stdout> for Stdio {
463    fn from(_: io::Stdout) -> Stdio {
464        // This ought really to be is Stdio::StaticFd(input_argument.as_fd()).
465        // But AsFd::as_fd takes its argument by reference, and yields
466        // a bounded lifetime, so it's no use here. There is no AsStaticFd.
467        //
468        // Additionally AsFd is only implemented for the *locked* versions.
469        // We don't want to lock them here.  (The implications of not locking
470        // are the same as those for process::Stdio::inherit().)
471        //
472        // Arguably the hypothetical AsStaticFd and AsFd<'static>
473        // should be implemented for io::Stdout, not just for StdoutLocked.
474        Stdio::StaticFd(unsafe { BorrowedFd::borrow_raw(libc::STDOUT_FILENO) })
475    }
476}
477
478impl From<io::Stderr> for Stdio {
479    fn from(_: io::Stderr) -> Stdio {
480        Stdio::StaticFd(unsafe { BorrowedFd::borrow_raw(libc::STDERR_FILENO) })
481    }
482}
483
484impl ChildStdio {
485    pub fn fd(&self) -> Option<c_int> {
486        match *self {
487            ChildStdio::Inherit => None,
488            ChildStdio::Explicit(fd) => Some(fd),
489            ChildStdio::Owned(ref fd) => Some(fd.as_raw_fd()),
490
491            #[cfg(target_os = "fuchsia")]
492            ChildStdio::Null => None,
493        }
494    }
495}
496
497impl fmt::Debug for Command {
498    // show all attributes but `self.closures` which does not implement `Debug`
499    // and `self.argv` which is not useful for debugging
500    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
501        if f.alternate() {
502            let mut debug_command = f.debug_struct("Command");
503            debug_command.field("program", &self.program).field("args", &self.args);
504            if !self.env.is_unchanged() {
505                debug_command.field("env", &self.env);
506            }
507
508            if self.cwd.is_some() {
509                debug_command.field("cwd", &self.cwd);
510            }
511            if self.uid.is_some() {
512                debug_command.field("uid", &self.uid);
513            }
514            if self.gid.is_some() {
515                debug_command.field("gid", &self.gid);
516            }
517
518            if self.groups.is_some() {
519                debug_command.field("groups", &self.groups);
520            }
521
522            if self.stdin.is_some() {
523                debug_command.field("stdin", &self.stdin);
524            }
525            if self.stdout.is_some() {
526                debug_command.field("stdout", &self.stdout);
527            }
528            if self.stderr.is_some() {
529                debug_command.field("stderr", &self.stderr);
530            }
531            if self.pgroup.is_some() {
532                debug_command.field("pgroup", &self.pgroup);
533            }
534
535            #[cfg(target_os = "linux")]
536            {
537                debug_command.field("create_pidfd", &self.create_pidfd);
538            }
539
540            debug_command.finish()
541        } else {
542            if let Some(ref cwd) = self.cwd {
543                write!(f, "cd {cwd:?} && ")?;
544            }
545            if self.env.does_clear() {
546                write!(f, "env -i ")?;
547                // Altered env vars will be printed next, that should exactly work as expected.
548            } else {
549                // Removed env vars need the command to be wrapped in `env`.
550                let mut any_removed = false;
551                for (key, value_opt) in self.get_envs() {
552                    if value_opt.is_none() {
553                        if !any_removed {
554                            write!(f, "env ")?;
555                            any_removed = true;
556                        }
557                        write!(f, "-u {} ", key.to_string_lossy())?;
558                    }
559                }
560            }
561            // Altered env vars can just be added in front of the program.
562            for (key, value_opt) in self.get_envs() {
563                if let Some(value) = value_opt {
564                    write!(f, "{}={value:?} ", key.to_string_lossy())?;
565                }
566            }
567
568            if *self.program != self.args[0] {
569                write!(f, "[{:?}] ", self.program)?;
570            }
571            write!(f, "{:?}", &self.args[0])?;
572
573            for arg in self.get_args() {
574                write!(f, " {:?}", arg)?;
575            }
576
577            Ok(())
578        }
579    }
580}
581
582#[derive(PartialEq, Eq, Clone, Copy)]
583pub struct ExitCode(u8);
584
585impl fmt::Debug for ExitCode {
586    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
587        f.debug_tuple("unix_exit_status").field(&self.0).finish()
588    }
589}
590
591impl ExitCode {
592    pub const SUCCESS: ExitCode = ExitCode(EXIT_SUCCESS as _);
593    pub const FAILURE: ExitCode = ExitCode(EXIT_FAILURE as _);
594
595    #[inline]
596    pub fn as_i32(&self) -> i32 {
597        self.0 as i32
598    }
599}
600
601impl From<u8> for ExitCode {
602    fn from(code: u8) -> Self {
603        Self(code)
604    }
605}
606
607pub struct CommandArgs<'a> {
608    iter: CStringIter<'a>,
609}
610
611impl<'a> Iterator for CommandArgs<'a> {
612    type Item = &'a OsStr;
613
614    fn next(&mut self) -> Option<&'a OsStr> {
615        self.iter.next().map(|cs| OsStr::from_bytes(cs.to_bytes()))
616    }
617
618    fn size_hint(&self) -> (usize, Option<usize>) {
619        self.iter.size_hint()
620    }
621}
622
623impl<'a> ExactSizeIterator for CommandArgs<'a> {
624    fn len(&self) -> usize {
625        self.iter.len()
626    }
627
628    fn is_empty(&self) -> bool {
629        self.iter.is_empty()
630    }
631}
632
633impl<'a> fmt::Debug for CommandArgs<'a> {
634    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
635        f.debug_list().entries(self.iter.clone()).finish()
636    }
637}
std/sys/process/unix/common.rs

std/sys/process/unix/
common.rs
