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Homogenize arguments for clone() and clone3()

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The arguments for both syscalls follow different formats. Rewrite the
CloneArgs struct to homogenize both formats into one.
This commit is contained in:
Carlos López
2024-09-24 21:16:04 +02:00
committed by Tate, Hongliang Tian
parent fad39fdf7a
commit 130a0f7030
2 changed files with 125 additions and 70 deletions
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155
kernel/src/process/clone.rs
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@ -1,6 +1,6 @@
// SPDX-License-Identifier: MPL-2.0
use core::sync::atomic::Ordering;
use core::{num::NonZeroU64, sync::atomic::Ordering};
use ostd::{
cpu::UserContext,
@ -12,7 +12,7 @@ use super::{
posix_thread::{thread_table, PosixThread, PosixThreadBuilder, PosixThreadExt, ThreadName},
process_table,
process_vm::ProcessVm,
signal::sig_disposition::SigDispositions,
signal::{constants::SIGCHLD, sig_disposition::SigDispositions, sig_num::SigNum},
Credentials, Process, ProcessBuilder,
};
use crate::{
@ -25,6 +25,7 @@ use crate::{
};
bitflags! {
#[derive(Default)]
pub struct CloneFlags: u32 {
const CLONE_VM = 0x00000100; /* Set if VM shared between processes. */
const CLONE_FS = 0x00000200; /* Set if fs info shared between processes. */
@ -53,45 +54,91 @@ bitflags! {
}
}
#[derive(Debug, Clone, Copy)]
/// An internal structure to homogenize the arguments for `clone` and
/// `clone3`.
///
/// From the clone(2) man page:
///
/// ```
/// The following table shows the equivalence between the arguments
/// of clone() and the fields in the clone_args argument supplied to
/// clone3():
/// clone() clone3() Notes
/// cl_args field
/// flags & ~0xff flags For most flags; details
/// below
/// parent_tid pidfd See CLONE_PIDFD
/// child_tid child_tid See CLONE_CHILD_SETTID
/// parent_tid parent_tid See CLONE_PARENT_SETTID
/// flags & 0xff exit_signal
/// stack stack
/// --- stack_size
/// tls tls See CLONE_SETTLS
/// --- set_tid See below for details
/// --- set_tid_size
/// --- cgroup See CLONE_INTO_CGROUP
/// ```
#[derive(Debug, Clone, Copy, Default)]
pub struct CloneArgs {
new_sp: u64,
stack_size: usize,
parent_tidptr: Vaddr,
child_tidptr: Vaddr,
tls: u64,
clone_flags: CloneFlags,
pub flags: CloneFlags,
pub _pidfd: Option<u64>,
pub child_tid: Vaddr,
pub parent_tid: Option<Vaddr>,
pub exit_signal: Option<SigNum>,
pub stack: u64,
pub stack_size: Option<NonZeroU64>,
pub tls: u64,
pub _set_tid: Option<u64>,
pub _set_tid_size: Option<u64>,
pub _cgroup: Option<u64>,
}
impl CloneArgs {
/// Clone Args for syscall fork.
/// TODO: set the correct values
pub const fn for_fork() -> Self {
CloneArgs {
new_sp: 0,
stack_size: 0,
parent_tidptr: 0,
child_tidptr: 0,
tls: 0,
clone_flags: CloneFlags::empty(),
}
/// Prepares a new [`CloneArgs`] based on the arguments for clone(2).
pub fn for_clone(
raw_flags: u64,
parent_tid: Vaddr,
child_tid: Vaddr,
tls: u64,
stack: u64,
) -> Result<Self> {
const FLAG_MASK: u64 = 0xff;
let flags = CloneFlags::from(raw_flags & !FLAG_MASK);
let exit_signal = raw_flags & FLAG_MASK;
// Disambiguate the `parent_tid` parameter. The field is used
// both for `CLONE_PIDFD` and `CLONE_PARENT_SETTID`, so at
// most only one can be specified.
let (pidfd, parent_tid) = match (
flags.contains(CloneFlags::CLONE_PIDFD),
flags.contains(CloneFlags::CLONE_PARENT_SETTID),
) {
(false, false) => (None, None),
(true, false) => (Some(parent_tid as u64), None),
(false, true) => (None, Some(parent_tid)),
(true, true) => {
return_errno_with_message!(
Errno::EINVAL,
"CLONE_PIDFD was specified with CLONE_PARENT_SETTID"
);
}
};
Ok(Self {
flags,
_pidfd: pidfd,
child_tid,
parent_tid,
exit_signal: (exit_signal != 0).then(|| SigNum::from_u8(exit_signal as u8)),
stack,
tls,
..Default::default()
})
}
pub const fn new(
new_sp: u64,
stack_size: usize,
parent_tidptr: Vaddr,
child_tidptr: Vaddr,
tls: u64,
clone_flags: CloneFlags,
) -> Self {
CloneArgs {
new_sp,
stack_size,
parent_tidptr,
child_tidptr,
tls,
clone_flags,
pub fn for_fork() -> Self {
Self {
exit_signal: Some(SIGCHLD),
..Default::default()
}
}
}
@ -133,8 +180,8 @@ pub fn clone_child(
parent_context: &UserContext,
clone_args: CloneArgs,
) -> Result<Tid> {
clone_args.clone_flags.check_unsupported_flags()?;
if clone_args.clone_flags.contains(CloneFlags::CLONE_THREAD) {
clone_args.flags.check_unsupported_flags()?;
if clone_args.flags.contains(CloneFlags::CLONE_THREAD) {
let child_task = clone_child_task(ctx, parent_context, clone_args)?;
let child_thread = Thread::borrow_from_task(&child_task);
child_thread.run();
@ -162,7 +209,7 @@ fn clone_child_task(
task: _,
} = ctx;
let clone_flags = clone_args.clone_flags;
let clone_flags = clone_args.flags;
debug_assert!(clone_flags.contains(CloneFlags::CLONE_VM));
debug_assert!(clone_flags.contains(CloneFlags::CLONE_FILES));
debug_assert!(clone_flags.contains(CloneFlags::CLONE_SIGHAND));
@ -172,7 +219,7 @@ fn clone_child_task(
let child_vm_space = child_root_vmar.vm_space().clone();
let child_cpu_context = clone_cpu_context(
parent_context,
clone_args.new_sp,
clone_args.stack,
clone_args.stack_size,
clone_args.tls,
clone_flags,
@ -200,9 +247,9 @@ fn clone_child_task(
process.tasks().lock().push(child_task.clone());
let child_posix_thread = child_task.as_posix_thread().unwrap();
clone_parent_settid(child_tid, clone_args.parent_tidptr, clone_flags)?;
clone_child_cleartid(child_posix_thread, clone_args.child_tidptr, clone_flags)?;
clone_child_settid(child_posix_thread, clone_args.child_tidptr, clone_flags)?;
clone_parent_settid(child_tid, clone_args.parent_tid, clone_flags)?;
clone_child_cleartid(child_posix_thread, clone_args.child_tid, clone_flags)?;
clone_child_settid(child_posix_thread, clone_args.child_tid, clone_flags)?;
Ok(child_task)
}
@ -218,7 +265,7 @@ fn clone_child_process(
task: _,
} = ctx;
let clone_flags = clone_args.clone_flags;
let clone_flags = clone_args.flags;
// clone vm
let child_process_vm = {
@ -230,7 +277,7 @@ fn clone_child_process(
let child_user_space = {
let child_cpu_context = clone_cpu_context(
parent_context,
clone_args.new_sp,
clone_args.stack,
clone_args.stack_size,
clone_args.tls,
clone_flags,
@ -301,9 +348,9 @@ fn clone_child_process(
// Deals with clone flags
let child_thread = thread_table::get_thread(child_tid).unwrap();
let child_posix_thread = child_thread.as_posix_thread().unwrap();
clone_parent_settid(child_tid, clone_args.parent_tidptr, clone_flags)?;
clone_child_cleartid(child_posix_thread, clone_args.child_tidptr, clone_flags)?;
clone_child_settid(child_posix_thread, clone_args.child_tidptr, clone_flags)?;
clone_parent_settid(child_tid, clone_args.parent_tid, clone_flags)?;
clone_child_cleartid(child_posix_thread, clone_args.child_tid, clone_flags)?;
clone_child_settid(child_posix_thread, clone_args.child_tid, clone_flags)?;
// Sets parent process and group for child process.
set_parent_and_group(process, &child);
@ -335,11 +382,13 @@ fn clone_child_settid(
fn clone_parent_settid(
child_tid: Tid,
parent_tidptr: Vaddr,
parent_tidptr: Option<Vaddr>,
clone_flags: CloneFlags,
) -> Result<()> {
if clone_flags.contains(CloneFlags::CLONE_PARENT_SETTID) {
get_current_userspace!().write_val(parent_tidptr, &child_tid)?;
if let Some(addr) =
parent_tidptr.filter(|_| clone_flags.contains(CloneFlags::CLONE_PARENT_SETTID))
{
get_current_userspace!().write_val(addr, &child_tid)?;
}
Ok(())
}
@ -357,7 +406,7 @@ fn clone_vm(parent_process_vm: &ProcessVm, clone_flags: CloneFlags) -> Result<Pr
fn clone_cpu_context(
parent_context: &UserContext,
new_sp: u64,
stack_size: usize,
stack_size: Option<NonZeroU64>,
tls: u64,
clone_flags: CloneFlags,
) -> UserContext {
@ -371,8 +420,8 @@ fn clone_cpu_context(
}
if new_sp != 0 {
// If stack size is not 0, the `new_sp` points to the BOTTOMMOST byte of stack.
if stack_size != 0 {
child_context.set_stack_pointer(new_sp as usize + stack_size);
if let Some(size) = stack_size {
child_context.set_stack_pointer((new_sp + size.get()) as usize)
}
// If stack size is 0, the new_sp points to the TOPMOST byte of stack.
else {