1 files changed, 523 insertions, 0 deletions
diff --git a/library/std/src/sys/unix/process/process_common.rs b/library/std/src/sys/unix/process/process_common.rs
new file mode 100644
index 000000000..bca1b65a7
--- /dev/null
+++ b/library/std/src/sys/unix/process/process_common.rs
@@ -0,0 +1,523 @@
+#[cfg(all(test, not(target_os = "emscripten")))]
+mod tests;
+
+use crate::os::unix::prelude::*;
+
+use crate::collections::BTreeMap;
+use crate::ffi::{CStr, CString, OsStr, OsString};
+use crate::fmt;
+use crate::io;
+use crate::path::Path;
+use crate::ptr;
+use crate::sys::fd::FileDesc;
+use crate::sys::fs::File;
+use crate::sys::pipe::{self, AnonPipe};
+use crate::sys_common::process::{CommandEnv, CommandEnvs};
+use crate::sys_common::IntoInner;
+
+#[cfg(not(target_os = "fuchsia"))]
+use crate::sys::fs::OpenOptions;
+
+use libc::{c_char, c_int, gid_t, pid_t, uid_t, EXIT_FAILURE, EXIT_SUCCESS};
+
+cfg_if::cfg_if! {
+    if #[cfg(target_os = "fuchsia")] {
+        // fuchsia doesn't have /dev/null
+    } else if #[cfg(target_os = "redox")] {
+        const DEV_NULL: &str = "null:\0";
+    } else if #[cfg(target_os = "vxworks")] {
+        const DEV_NULL: &str = "/null\0";
+    } else {
+        const DEV_NULL: &str = "/dev/null\0";
+    }
+}
+
+// Android with api less than 21 define sig* functions inline, so it is not
+// available for dynamic link. Implementing sigemptyset and sigaddset allow us
+// to support older Android version (independent of libc version).
+// The following implementations are based on
+// https://github.com/aosp-mirror/platform_bionic/blob/ad8dcd6023294b646e5a8288c0ed431b0845da49/libc/include/android/legacy_signal_inlines.h
+cfg_if::cfg_if! {
+    if #[cfg(target_os = "android")] {
+        pub unsafe fn sigemptyset(set: *mut libc::sigset_t) -> libc::c_int {
+            set.write_bytes(0u8, 1);
+            return 0;
+        }
+        #[allow(dead_code)]
+        pub unsafe fn sigaddset(set: *mut libc::sigset_t, signum: libc::c_int) -> libc::c_int {
+            use crate::{slice, mem};
+
+            let raw = slice::from_raw_parts_mut(set as *mut u8, mem::size_of::<libc::sigset_t>());
+            let bit = (signum - 1) as usize;
+            raw[bit / 8] |= 1 << (bit % 8);
+            return 0;
+        }
+    } else {
+        pub use libc::{sigemptyset, sigaddset};
+    }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Command
+////////////////////////////////////////////////////////////////////////////////
+
+pub struct Command {
+    program: CString,
+    args: Vec<CString>,
+    /// Exactly what will be passed to `execvp`.
+    ///
+    /// First element is a pointer to `program`, followed by pointers to
+    /// `args`, followed by a `null`. Be careful when modifying `program` or
+    /// `args` to properly update this as well.
+    argv: Argv,
+    env: CommandEnv,
+
+    cwd: Option<CString>,
+    uid: Option<uid_t>,
+    gid: Option<gid_t>,
+    saw_nul: bool,
+    closures: Vec<Box<dyn FnMut() -> io::Result<()> + Send + Sync>>,
+    groups: Option<Box<[gid_t]>>,
+    stdin: Option<Stdio>,
+    stdout: Option<Stdio>,
+    stderr: Option<Stdio>,
+    #[cfg(target_os = "linux")]
+    create_pidfd: bool,
+    pgroup: Option<pid_t>,
+}
+
+// Create a new type for argv, so that we can make it `Send` and `Sync`
+struct Argv(Vec<*const c_char>);
+
+// It is safe to make `Argv` `Send` and `Sync`, because it contains
+// pointers to memory owned by `Command.args`
+unsafe impl Send for Argv {}
+unsafe impl Sync for Argv {}
+
+// passed back to std::process with the pipes connected to the child, if any
+// were requested
+pub struct StdioPipes {
+    pub stdin: Option<AnonPipe>,
+    pub stdout: Option<AnonPipe>,
+    pub stderr: Option<AnonPipe>,
+}
+
+// passed to do_exec() with configuration of what the child stdio should look
+// like
+pub struct ChildPipes {
+    pub stdin: ChildStdio,
+    pub stdout: ChildStdio,
+    pub stderr: ChildStdio,
+}
+
+pub enum ChildStdio {
+    Inherit,
+    Explicit(c_int),
+    Owned(FileDesc),
+
+    // On Fuchsia, null stdio is the default, so we simply don't specify
+    // any actions at the time of spawning.
+    #[cfg(target_os = "fuchsia")]
+    Null,
+}
+
+pub enum Stdio {
+    Inherit,
+    Null,
+    MakePipe,
+    Fd(FileDesc),
+}
+
+impl Command {
+    #[cfg(not(target_os = "linux"))]
+    pub fn new(program: &OsStr) -> Command {
+        let mut saw_nul = false;
+        let program = os2c(program, &mut saw_nul);
+        Command {
+            argv: Argv(vec![program.as_ptr(), ptr::null()]),
+            args: vec![program.clone()],
+            program,
+            env: Default::default(),
+            cwd: None,
+            uid: None,
+            gid: None,
+            saw_nul,
+            closures: Vec::new(),
+            groups: None,
+            stdin: None,
+            stdout: None,
+            stderr: None,
+            pgroup: None,
+        }
+    }
+
+    #[cfg(target_os = "linux")]
+    pub fn new(program: &OsStr) -> Command {
+        let mut saw_nul = false;
+        let program = os2c(program, &mut saw_nul);
+        Command {
+            argv: Argv(vec![program.as_ptr(), ptr::null()]),
+            args: vec![program.clone()],
+            program,
+            env: Default::default(),
+            cwd: None,
+            uid: None,
+            gid: None,
+            saw_nul,
+            closures: Vec::new(),
+            groups: None,
+            stdin: None,
+            stdout: None,
+            stderr: None,
+            create_pidfd: false,
+            pgroup: None,
+        }
+    }
+
+    pub fn set_arg_0(&mut self, arg: &OsStr) {
+        // Set a new arg0
+        let arg = os2c(arg, &mut self.saw_nul);
+        debug_assert!(self.argv.0.len() > 1);
+        self.argv.0[0] = arg.as_ptr();
+        self.args[0] = arg;
+    }
+
+    pub fn arg(&mut self, arg: &OsStr) {
+        // Overwrite the trailing null pointer in `argv` and then add a new null
+        // pointer.
+        let arg = os2c(arg, &mut self.saw_nul);
+        self.argv.0[self.args.len()] = arg.as_ptr();
+        self.argv.0.push(ptr::null());
+
+        // Also make sure we keep track of the owned value to schedule a
+        // destructor for this memory.
+        self.args.push(arg);
+    }
+
+    pub fn cwd(&mut self, dir: &OsStr) {
+        self.cwd = Some(os2c(dir, &mut self.saw_nul));
+    }
+    pub fn uid(&mut self, id: uid_t) {
+        self.uid = Some(id);
+    }
+    pub fn gid(&mut self, id: gid_t) {
+        self.gid = Some(id);
+    }
+    pub fn groups(&mut self, groups: &[gid_t]) {
+        self.groups = Some(Box::from(groups));
+    }
+    pub fn pgroup(&mut self, pgroup: pid_t) {
+        self.pgroup = Some(pgroup);
+    }
+
+    #[cfg(target_os = "linux")]
+    pub fn create_pidfd(&mut self, val: bool) {
+        self.create_pidfd = val;
+    }
+
+    #[cfg(not(target_os = "linux"))]
+    #[allow(dead_code)]
+    pub fn get_create_pidfd(&self) -> bool {
+        false
+    }
+
+    #[cfg(target_os = "linux")]
+    pub fn get_create_pidfd(&self) -> bool {
+        self.create_pidfd
+    }
+
+    pub fn saw_nul(&self) -> bool {
+        self.saw_nul
+    }
+
+    pub fn get_program(&self) -> &OsStr {
+        OsStr::from_bytes(self.program.as_bytes())
+    }
+
+    pub fn get_args(&self) -> CommandArgs<'_> {
+        let mut iter = self.args.iter();
+        iter.next();
+        CommandArgs { iter }
+    }
+
+    pub fn get_envs(&self) -> CommandEnvs<'_> {
+        self.env.iter()
+    }
+
+    pub fn get_current_dir(&self) -> Option<&Path> {
+        self.cwd.as_ref().map(|cs| Path::new(OsStr::from_bytes(cs.as_bytes())))
+    }
+
+    pub fn get_argv(&self) -> &Vec<*const c_char> {
+        &self.argv.0
+    }
+
+    pub fn get_program_cstr(&self) -> &CStr {
+        &*self.program
+    }
+
+    #[allow(dead_code)]
+    pub fn get_cwd(&self) -> &Option<CString> {
+        &self.cwd
+    }
+    #[allow(dead_code)]
+    pub fn get_uid(&self) -> Option<uid_t> {
+        self.uid
+    }
+    #[allow(dead_code)]
+    pub fn get_gid(&self) -> Option<gid_t> {
+        self.gid
+    }
+    #[allow(dead_code)]
+    pub fn get_groups(&self) -> Option<&[gid_t]> {
+        self.groups.as_deref()
+    }
+    #[allow(dead_code)]
+    pub fn get_pgroup(&self) -> Option<pid_t> {
+        self.pgroup
+    }
+
+    pub fn get_closures(&mut self) -> &mut Vec<Box<dyn FnMut() -> io::Result<()> + Send + Sync>> {
+        &mut self.closures
+    }
+
+    pub unsafe fn pre_exec(&mut self, f: Box<dyn FnMut() -> io::Result<()> + Send + Sync>) {
+        self.closures.push(f);
+    }
+
+    pub fn stdin(&mut self, stdin: Stdio) {
+        self.stdin = Some(stdin);
+    }
+
+    pub fn stdout(&mut self, stdout: Stdio) {
+        self.stdout = Some(stdout);
+    }
+
+    pub fn stderr(&mut self, stderr: Stdio) {
+        self.stderr = Some(stderr);
+    }
+
+    pub fn env_mut(&mut self) -> &mut CommandEnv {
+        &mut self.env
+    }
+
+    pub fn capture_env(&mut self) -> Option<CStringArray> {
+        let maybe_env = self.env.capture_if_changed();
+        maybe_env.map(|env| construct_envp(env, &mut self.saw_nul))
+    }
+
+    #[allow(dead_code)]
+    pub fn env_saw_path(&self) -> bool {
+        self.env.have_changed_path()
+    }
+
+    #[allow(dead_code)]
+    pub fn program_is_path(&self) -> bool {
+        self.program.to_bytes().contains(&b'/')
+    }
+
+    pub fn setup_io(
+        &self,
+        default: Stdio,
+        needs_stdin: bool,
+    ) -> io::Result<(StdioPipes, ChildPipes)> {
+        let null = Stdio::Null;
+        let default_stdin = if needs_stdin { &default } else { &null };
+        let stdin = self.stdin.as_ref().unwrap_or(default_stdin);
+        let stdout = self.stdout.as_ref().unwrap_or(&default);
+        let stderr = self.stderr.as_ref().unwrap_or(&default);
+        let (their_stdin, our_stdin) = stdin.to_child_stdio(true)?;
+        let (their_stdout, our_stdout) = stdout.to_child_stdio(false)?;
+        let (their_stderr, our_stderr) = stderr.to_child_stdio(false)?;
+        let ours = StdioPipes { stdin: our_stdin, stdout: our_stdout, stderr: our_stderr };
+        let theirs = ChildPipes { stdin: their_stdin, stdout: their_stdout, stderr: their_stderr };
+        Ok((ours, theirs))
+    }
+}
+
+fn os2c(s: &OsStr, saw_nul: &mut bool) -> CString {
+    CString::new(s.as_bytes()).unwrap_or_else(|_e| {
+        *saw_nul = true;
+        CString::new("<string-with-nul>").unwrap()
+    })
+}
+
+// Helper type to manage ownership of the strings within a C-style array.
+pub struct CStringArray {
+    items: Vec<CString>,
+    ptrs: Vec<*const c_char>,
+}
+
+impl CStringArray {
+    pub fn with_capacity(capacity: usize) -> Self {
+        let mut result = CStringArray {
+            items: Vec::with_capacity(capacity),
+            ptrs: Vec::with_capacity(capacity + 1),
+        };
+        result.ptrs.push(ptr::null());
+        result
+    }
+    pub fn push(&mut self, item: CString) {
+        let l = self.ptrs.len();
+        self.ptrs[l - 1] = item.as_ptr();
+        self.ptrs.push(ptr::null());
+        self.items.push(item);
+    }
+    pub fn as_ptr(&self) -> *const *const c_char {
+        self.ptrs.as_ptr()
+    }
+}
+
+fn construct_envp(env: BTreeMap<OsString, OsString>, saw_nul: &mut bool) -> CStringArray {
+    let mut result = CStringArray::with_capacity(env.len());
+    for (mut k, v) in env {
+        // Reserve additional space for '=' and null terminator
+        k.reserve_exact(v.len() + 2);
+        k.push("=");
+        k.push(&v);
+
+        // Add the new entry into the array
+        if let Ok(item) = CString::new(k.into_vec()) {
+            result.push(item);
+        } else {
+            *saw_nul = true;
+        }
+    }
+
+    result
+}
+
+impl Stdio {
+    pub fn to_child_stdio(&self, readable: bool) -> io::Result<(ChildStdio, Option<AnonPipe>)> {
+        match *self {
+            Stdio::Inherit => Ok((ChildStdio::Inherit, None)),
+
+            // Make sure that the source descriptors are not an stdio
+            // descriptor, otherwise the order which we set the child's
+            // descriptors may blow away a descriptor which we are hoping to
+            // save. For example, suppose we want the child's stderr to be the
+            // parent's stdout, and the child's stdout to be the parent's
+            // stderr. No matter which we dup first, the second will get
+            // overwritten prematurely.
+            Stdio::Fd(ref fd) => {
+                if fd.as_raw_fd() >= 0 && fd.as_raw_fd() <= libc::STDERR_FILENO {
+                    Ok((ChildStdio::Owned(fd.duplicate()?), None))
+                } else {
+                    Ok((ChildStdio::Explicit(fd.as_raw_fd()), None))
+                }
+            }
+
+            Stdio::MakePipe => {
+                let (reader, writer) = pipe::anon_pipe()?;
+                let (ours, theirs) = if readable { (writer, reader) } else { (reader, writer) };
+                Ok((ChildStdio::Owned(theirs.into_inner()), Some(ours)))
+            }
+
+            #[cfg(not(target_os = "fuchsia"))]
+            Stdio::Null => {
+                let mut opts = OpenOptions::new();
+                opts.read(readable);
+                opts.write(!readable);
+                let path = unsafe { CStr::from_ptr(DEV_NULL.as_ptr() as *const _) };
+                let fd = File::open_c(&path, &opts)?;
+                Ok((ChildStdio::Owned(fd.into_inner()), None))
+            }
+
+            #[cfg(target_os = "fuchsia")]
+            Stdio::Null => Ok((ChildStdio::Null, None)),
+        }
+    }
+}
+
+impl From<AnonPipe> for Stdio {
+    fn from(pipe: AnonPipe) -> Stdio {
+        Stdio::Fd(pipe.into_inner())
+    }
+}
+
+impl From<File> for Stdio {
+    fn from(file: File) -> Stdio {
+        Stdio::Fd(file.into_inner())
+    }
+}
+
+impl ChildStdio {
+    pub fn fd(&self) -> Option<c_int> {
+        match *self {
+            ChildStdio::Inherit => None,
+            ChildStdio::Explicit(fd) => Some(fd),
+            ChildStdio::Owned(ref fd) => Some(fd.as_raw_fd()),
+
+            #[cfg(target_os = "fuchsia")]
+            ChildStdio::Null => None,
+        }
+    }
+}
+
+impl fmt::Debug for Command {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        if self.program != self.args[0] {
+            write!(f, "[{:?}] ", self.program)?;
+        }
+        write!(f, "{:?}", self.args[0])?;
+
+        for arg in &self.args[1..] {
+            write!(f, " {:?}", arg)?;
+        }
+        Ok(())
+    }
+}
+
+#[derive(PartialEq, Eq, Clone, Copy)]
+pub struct ExitCode(u8);
+
+impl fmt::Debug for ExitCode {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_tuple("unix_exit_status").field(&self.0).finish()
+    }
+}
+
+impl ExitCode {
+    pub const SUCCESS: ExitCode = ExitCode(EXIT_SUCCESS as _);
+    pub const FAILURE: ExitCode = ExitCode(EXIT_FAILURE as _);
+
+    #[inline]
+    pub fn as_i32(&self) -> i32 {
+        self.0 as i32
+    }
+}
+
+impl From<u8> for ExitCode {
+    fn from(code: u8) -> Self {
+        Self(code)
+    }
+}
+
+pub struct CommandArgs<'a> {
+    iter: crate::slice::Iter<'a, CString>,
+}
+
+impl<'a> Iterator for CommandArgs<'a> {
+    type Item = &'a OsStr;
+    fn next(&mut self) -> Option<&'a OsStr> {
+        self.iter.next().map(|cs| OsStr::from_bytes(cs.as_bytes()))
+    }
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.iter.size_hint()
+    }
+}
+
+impl<'a> ExactSizeIterator for CommandArgs<'a> {
+    fn len(&self) -> usize {
+        self.iter.len()
+    }
+    fn is_empty(&self) -> bool {
+        self.iter.is_empty()
+    }
+}
+
+impl<'a> fmt::Debug for CommandArgs<'a> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_list().entries(self.iter.clone()).finish()
+    }
+}