cloudfox-coreshift-core 2.5.0

// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at https://mozilla.org/MPL/2.0/

//! `posix_spawn` backend.
//!
//! Owns the `posix_spawn` FFI bindings, spawn flags, and the launch path
//! used when [`SpawnBackend::PosixSpawn`](crate::spawn::SpawnBackend::PosixSpawn) is selected.

use std::mem::MaybeUninit;

use crate::CoreError;
use crate::error::posix_ret;
use crate::signal::SignalRuntime;
use libc::{c_char, pid_t};

use super::exec::ExecArgv;
use super::{environ, Pipes, SpawnDrain, SpawnOptions};

pub(crate) const POSIX_SPAWN_SETPGROUP: i32 = 2;
pub(crate) const POSIX_SPAWN_SETSIGDEF: i32 = 4;
pub(crate) const POSIX_SPAWN_SETSIGMASK: i32 = 8;

unsafe extern "C" {
    pub(crate) fn posix_spawn(
        pid: *mut libc::pid_t,
        path: *const libc::c_char,
        file_actions: *const libc::posix_spawn_file_actions_t,
        attrp: *const libc::posix_spawnattr_t,
        argv: *const *mut libc::c_char,
        envp: *const *mut libc::c_char,
    ) -> libc::c_int;

    pub(crate) fn posix_spawn_file_actions_addclose(
        file_actions: *mut libc::posix_spawn_file_actions_t,
        fd: libc::c_int,
    ) -> libc::c_int;

    pub(crate) fn posix_spawn_file_actions_adddup2(
        file_actions: *mut libc::posix_spawn_file_actions_t,
        fd: libc::c_int,
        newfd: libc::c_int,
    ) -> libc::c_int;

    pub(crate) fn posix_spawn_file_actions_destroy(
        file_actions: *mut libc::posix_spawn_file_actions_t,
    ) -> libc::c_int;

    pub(crate) fn posix_spawn_file_actions_init(
        file_actions: *mut libc::posix_spawn_file_actions_t,
    ) -> libc::c_int;

    pub(crate) fn posix_spawnattr_destroy(attr: *mut libc::posix_spawnattr_t) -> libc::c_int;

    pub(crate) fn posix_spawnattr_init(attr: *mut libc::posix_spawnattr_t) -> libc::c_int;

    pub(crate) fn posix_spawnattr_setflags(
        attr: *mut libc::posix_spawnattr_t,
        flags: libc::c_short,
    ) -> libc::c_int;

    pub(crate) fn posix_spawnattr_setpgroup(
        attr: *mut libc::posix_spawnattr_t,
        pgroup: libc::pid_t,
    ) -> libc::c_int;

    pub(crate) fn posix_spawnattr_setsigdefault(
        attr: *mut libc::posix_spawnattr_t,
        sigdefault: *const libc::sigset_t,
    ) -> libc::c_int;

    pub(crate) fn posix_spawnattr_setsigmask(
        attr: *mut libc::posix_spawnattr_t,
        sigmask: *const libc::sigset_t,
    ) -> libc::c_int;
}

pub(super) fn spawn_posix_internal(opts: SpawnOptions) -> Result<(pid_t, SpawnDrain), CoreError> {
    let mut pipes = Pipes::new(
        opts.stdin.as_deref(),
        opts.capture_stdout,
        opts.capture_stderr,
    )?;

    let exe_ptr = match &opts.ctx.argv {
        ExecArgv::Dynamic(v) => v[0].as_ptr(),
    };

    let argv = opts.ctx.get_argv_ptrs();
    let envp = opts.ctx.get_envp_ptrs();

    let actions = MaybeUninit::zeroed();
    let mut actions = unsafe { actions.assume_init() };
    if let Err(e) = posix_ret(
        unsafe { posix_spawn_file_actions_init(&mut actions) },
        "file_actions_init",
    ) {
        pipes.close_all();
        return Err(e);
    }

    struct Actions(*mut libc::posix_spawn_file_actions_t);
    impl Drop for Actions {
        fn drop(&mut self) {
            unsafe {
                posix_spawn_file_actions_destroy(self.0);
            }
        }
    }
    let _guard = Actions(&mut actions);

    if let (Some(r), Some(w)) = (&pipes.stdin_r, &pipes.stdin_w) {
        if let Err(e) = posix_ret(
            unsafe { posix_spawn_file_actions_adddup2(&mut actions, r.raw(), 0) },
            "dup2 stdin",
        ) {
            pipes.close_all();
            return Err(e);
        }
        if let Err(e) = posix_ret(
            unsafe { posix_spawn_file_actions_addclose(&mut actions, r.raw()) },
            "close stdin pipe",
        ) {
            pipes.close_all();
            return Err(e);
        }
        if let Err(e) = posix_ret(
            unsafe { posix_spawn_file_actions_addclose(&mut actions, w.raw()) },
            "close stdin write pipe",
        ) {
            pipes.close_all();
            return Err(e);
        }
    }

    if let (Some(r), Some(w)) = (&pipes.stdout_r, &pipes.stdout_w) {
        if let Err(e) = posix_ret(
            unsafe { posix_spawn_file_actions_adddup2(&mut actions, w.raw(), 1) },
            "dup2 stdout",
        ) {
            pipes.close_all();
            return Err(e);
        }
        if let Err(e) = posix_ret(
            unsafe { posix_spawn_file_actions_addclose(&mut actions, w.raw()) },
            "close stdout pipe",
        ) {
            pipes.close_all();
            return Err(e);
        }
        if let Err(e) = posix_ret(
            unsafe { posix_spawn_file_actions_addclose(&mut actions, r.raw()) },
            "close stdout read pipe",
        ) {
            pipes.close_all();
            return Err(e);
        }
    }

    if let (Some(r), Some(w)) = (&pipes.stderr_r, &pipes.stderr_w) {
        if let Err(e) = posix_ret(
            unsafe { posix_spawn_file_actions_adddup2(&mut actions, w.raw(), 2) },
            "dup2 stderr",
        ) {
            pipes.close_all();
            return Err(e);
        }
        if let Err(e) = posix_ret(
            unsafe { posix_spawn_file_actions_addclose(&mut actions, w.raw()) },
            "close stderr pipe",
        ) {
            pipes.close_all();
            return Err(e);
        }
        if let Err(e) = posix_ret(
            unsafe { posix_spawn_file_actions_addclose(&mut actions, r.raw()) },
            "close stderr read pipe",
        ) {
            pipes.close_all();
            return Err(e);
        }
    }

    let attr = MaybeUninit::zeroed();
    let mut attr = unsafe { attr.assume_init() };
    if let Err(e) = posix_ret(unsafe { posix_spawnattr_init(&mut attr) }, "attr_init") {
        pipes.close_all();
        return Err(e);
    }

    struct Attr(*mut libc::posix_spawnattr_t);
    impl Drop for Attr {
        fn drop(&mut self) {
            unsafe {
                posix_spawnattr_destroy(self.0);
            }
        }
    }
    let _attr = Attr(&mut attr);

    let mut flags = 0;

    if let Some(pg) = opts.pgroup.leader {
        flags |= POSIX_SPAWN_SETPGROUP;
        if let Err(e) = posix_ret(
            unsafe { posix_spawnattr_setpgroup(&mut attr, pg) },
            "setpgroup",
        ) {
            pipes.close_all();
            return Err(e);
        }
    }

    flags |= POSIX_SPAWN_SETSIGMASK | POSIX_SPAWN_SETSIGDEF;

    if let Err(e) = posix_ret(
        unsafe { posix_spawnattr_setflags(&mut attr, flags as _) },
        "setflags",
    ) {
        pipes.close_all();
        return Err(e);
    }

    let empty_mask = SignalRuntime::empty_set();
    let def = SignalRuntime::set_with(&[libc::SIGPIPE])?;

    if let Err(e) = posix_ret(
        unsafe { posix_spawnattr_setsigmask(&mut attr, &empty_mask) },
        "setsigmask",
    ) {
        pipes.close_all();
        return Err(e);
    }
    if let Err(e) = posix_ret(
        unsafe { posix_spawnattr_setsigdefault(&mut attr, &def) },
        "setsigdefault",
    ) {
        pipes.close_all();
        return Err(e);
    }

    let mut pid: pid_t = 0;

    let envp_ptr = envp.as_ref().map_or_else(
        || unsafe { environ as *const *mut c_char },
        |e: &Vec<*mut c_char>| e.as_ptr(),
    );

    if let Err(e) = posix_ret(
        unsafe { posix_spawn(&mut pid, exe_ptr, &actions, &attr, argv.as_ptr(), envp_ptr) },
        "posix_spawn",
    ) {
        pipes.close_all();
        return Err(e);
    }

    drop(pipes.stdin_r.take());
    drop(pipes.stdout_w.take());
    drop(pipes.stderr_w.take());

    let drain = crate::io::DrainState::new(
        pipes.stdin_w.take().filter(|_| opts.stdin.is_some()),
        opts.stdin,
        pipes.stdout_r.take(),
        pipes.stderr_r.take(),
        opts.max_output,
        opts.early_exit,
    )?;

    Ok((pid, drain))
}