asterinas/kernel/src/syscall/getsid.rs

// SPDX-License-Identifier: MPL-2.0

use super::SyscallReturn;
use crate::{
    prelude::*,
    process::{process_table, Pid},
};

pub fn sys_getsid(pid: Pid, ctx: &Context) -> Result<SyscallReturn> {
    debug!("pid = {}", pid);

    let session = ctx.process.session().unwrap();
    let sid = session.sid();

    if pid == 0 {
        return Ok(SyscallReturn::Return(sid as _));
    }

    let Some(process) = process_table::get_process(pid) else {
        return_errno_with_message!(Errno::ESRCH, "the process does not exist")
    };

    if !Arc::ptr_eq(&session, &process.session().unwrap()) {
        return_errno_with_message!(
            Errno::EPERM,
            "the process and current process does not belong to the same session"
        );
    }

    Ok(SyscallReturn::Return(sid as _))
}