4lDO2
541 lines
18 KiB
Rust
541 lines
18 KiB
Rust
use alloc::sync::Weak;
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use alloc::{
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boxed::Box,
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collections::VecDeque,
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sync::Arc,
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vec::Vec, borrow::Cow,
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};
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use core::{
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cmp::Ordering,
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mem,
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};
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use spin::RwLock;
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use crate::arch::{interrupt::InterruptStack, paging::PAGE_SIZE};
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use crate::common::aligned_box::AlignedBox;
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use crate::common::unique::Unique;
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use crate::context::{self, arch};
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use crate::context::file::{FileDescriptor, FileDescription};
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use crate::context::memory::AddrSpace;
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use crate::ipi::{ipi, IpiKind, IpiTarget};
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use crate::paging::{RmmA, RmmArch};
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use crate::memory::{RaiiFrame, Frame};
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use crate::scheme::{SchemeNamespace, FileHandle};
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use crate::sync::WaitMap;
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use crate::syscall::data::SigAction;
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use crate::syscall::error::{Result, Error, EAGAIN, EINVAL, ESRCH};
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use crate::syscall::flag::{SIG_DFL, SigActionFlags};
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/// Unique identifier for a context (i.e. `pid`).
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use ::core::sync::atomic::AtomicUsize;
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use super::memory::GrantFileRef;
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int_like!(ContextId, AtomicContextId, usize, AtomicUsize);
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/// The status of a context - used for scheduling
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/// See `syscall::process::waitpid` and the `sync` module for examples of usage
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#[derive(Clone, Debug)]
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pub enum Status {
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Runnable,
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// TODO: Rename to SoftBlocked and move status_reason to this variant.
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/// Not currently runnable, typically due to some blocking syscall, but it can be trivially
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/// unblocked by e.g. signals.
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Blocked,
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/// Not currently runnable, and cannot be runnable until manually unblocked, depending on what
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/// reason.
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HardBlocked { reason: HardBlockedReason },
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Stopped(usize),
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Exited(usize),
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}
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impl Status {
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pub fn is_runnable(&self) -> bool {
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matches!(self, Self::Runnable)
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}
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pub fn is_soft_blocked(&self) -> bool {
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matches!(self, Self::Blocked)
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}
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}
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#[derive(Clone, Debug)]
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pub enum HardBlockedReason {
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AwaitingMmap { file_ref: GrantFileRef },
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// TODO: PageFaultOom?
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// TODO: NotYetStarted/ManuallyBlocked (when new contexts are created)
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// TODO: ptrace_stop?
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}
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#[derive(Copy, Clone, Debug)]
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pub struct WaitpidKey {
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pub pid: Option<ContextId>,
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pub pgid: Option<ContextId>,
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}
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impl Ord for WaitpidKey {
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fn cmp(&self, other: &WaitpidKey) -> Ordering {
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// If both have pid set, compare that
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if let Some(s_pid) = self.pid {
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if let Some(o_pid) = other.pid {
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return s_pid.cmp(&o_pid);
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}
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}
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// If both have pgid set, compare that
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if let Some(s_pgid) = self.pgid {
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if let Some(o_pgid) = other.pgid {
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return s_pgid.cmp(&o_pgid);
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}
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}
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// If either has pid set, it is greater
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if self.pid.is_some() {
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return Ordering::Greater;
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}
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if other.pid.is_some() {
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return Ordering::Less;
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}
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// If either has pgid set, it is greater
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if self.pgid.is_some() {
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return Ordering::Greater;
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}
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if other.pgid.is_some() {
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return Ordering::Less;
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}
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// If all pid and pgid are None, they are equal
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Ordering::Equal
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}
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}
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impl PartialOrd for WaitpidKey {
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fn partial_cmp(&self, other: &WaitpidKey) -> Option<Ordering> {
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Some(self.cmp(other))
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}
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}
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impl PartialEq for WaitpidKey {
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fn eq(&self, other: &WaitpidKey) -> bool {
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self.cmp(other) == Ordering::Equal
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}
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}
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impl Eq for WaitpidKey {}
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pub struct ContextSnapshot {
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// Copy fields
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pub id: ContextId,
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pub pgid: ContextId,
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pub ppid: ContextId,
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pub ruid: u32,
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pub rgid: u32,
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pub rns: SchemeNamespace,
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pub euid: u32,
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pub egid: u32,
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pub ens: SchemeNamespace,
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pub sigmask: [u64; 2],
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pub umask: usize,
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pub status: Status,
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pub status_reason: &'static str,
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pub running: bool,
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pub cpu_id: Option<usize>,
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pub cpu_time: u128,
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pub sched_affinity: Option<usize>,
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pub syscall: Option<(usize, usize, usize, usize, usize, usize)>,
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// Clone fields
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//TODO: is there a faster way than allocation?
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pub name: Box<str>,
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pub files: Vec<Option<FileDescription>>,
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}
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impl ContextSnapshot {
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//TODO: Should this accept &mut Context to ensure name/files will not change?
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pub fn new(context: &Context) -> Self {
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let name = context.name.clone().into_owned().into_boxed_str();
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let mut files = Vec::new();
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for descriptor_opt in context.files.read().iter() {
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let description = if let Some(descriptor) = descriptor_opt {
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let description = descriptor.description.read();
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Some(FileDescription {
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namespace: description.namespace,
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scheme: description.scheme,
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number: description.number,
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flags: description.flags,
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})
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} else {
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None
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};
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files.push(description);
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}
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Self {
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id: context.id,
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pgid: context.pgid,
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ppid: context.ppid,
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ruid: context.ruid,
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rgid: context.rgid,
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rns: context.rns,
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euid: context.euid,
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egid: context.egid,
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ens: context.ens,
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sigmask: context.sigmask,
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umask: context.umask,
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status: context.status.clone(),
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status_reason: context.status_reason,
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running: context.running,
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cpu_id: context.cpu_id,
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cpu_time: context.cpu_time,
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sched_affinity: context.sched_affinity,
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syscall: context.syscall,
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name,
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files,
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}
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}
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}
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/// A context, which identifies either a process or a thread
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#[derive(Debug)]
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pub struct Context {
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/// The ID of this context
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pub id: ContextId,
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/// The group ID of this context
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pub pgid: ContextId,
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/// The ID of the parent context
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pub ppid: ContextId,
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/// The real user id
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pub ruid: u32,
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/// The real group id
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pub rgid: u32,
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/// The real namespace id
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pub rns: SchemeNamespace,
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/// The effective user id
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pub euid: u32,
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/// The effective group id
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pub egid: u32,
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/// The effective namespace id
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pub ens: SchemeNamespace,
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/// Signal mask
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pub sigmask: [u64; 2],
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/// Process umask
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pub umask: usize,
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/// Status of context
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pub status: Status,
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pub status_reason: &'static str,
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/// Context running or not
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pub running: bool,
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/// Current CPU ID
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pub cpu_id: Option<usize>,
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/// Time this context was switched to
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pub switch_time: u128,
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/// Amount of CPU time used
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pub cpu_time: u128,
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/// Scheduler CPU affinity. If set, [`cpu_id`] can except [`None`] never be anything else than
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/// this value.
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// TODO: bitmask (selection of multiple allowed CPUs)?
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pub sched_affinity: Option<usize>,
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/// Current system call
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pub syscall: Option<(usize, usize, usize, usize, usize, usize)>,
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/// Head buffer to use when system call buffers are not page aligned
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// TODO: Store in user memory?
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pub syscall_head: Option<RaiiFrame>,
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/// Tail buffer to use when system call buffers are not page aligned
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// TODO: Store in user memory?
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pub syscall_tail: Option<RaiiFrame>,
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/// Context is being waited on
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pub waitpid: Arc<WaitMap<WaitpidKey, (ContextId, usize)>>,
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/// Context should handle pending signals
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pub pending: VecDeque<u8>,
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/// Context should wake up at specified time
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pub wake: Option<u128>,
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/// The architecture specific context
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pub arch: arch::Context,
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/// Kernel FX - used to store SIMD and FPU registers on context switch
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pub kfx: AlignedBox<[u8; arch::KFX_SIZE], {arch::KFX_ALIGN}>,
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/// Kernel stack
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pub kstack: Option<Box<[u8]>>,
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/// Kernel signal backup: Registers, Kernel FX, Kernel Stack, Signal number
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pub ksig: Option<(arch::Context, AlignedBox<[u8; arch::KFX_SIZE], {arch::KFX_ALIGN}>, Option<Box<[u8]>>, u8)>,
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/// Restore ksig context on next switch
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pub ksig_restore: bool,
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/// Address space containing a page table lock, and grants. Normally this will have a value,
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/// but can be None while the context is being reaped or when a new context is created but has
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/// not yet had its address space changed. Note that these are only for user mappings; kernel
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/// mappings are universal and independent on address spaces or contexts.
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pub addr_space: Option<Arc<RwLock<AddrSpace>>>,
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/// The name of the context
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// TODO: fixed size ArrayString?
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pub name: Cow<'static, str>,
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/// The open files in the scheme
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pub files: Arc<RwLock<Vec<Option<FileDescriptor>>>>,
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/// Signal actions
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pub actions: Arc<RwLock<Vec<(SigAction, usize)>>>,
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/// The pointer to the user-space registers, saved after certain
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/// interrupts. This pointer is somewhere inside kstack, and the
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/// kstack address at the time of creation is the first element in
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/// this tuple.
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pub regs: Option<(usize, Unique<InterruptStack>)>,
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/// A somewhat hacky way to initially stop a context when creating
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/// a new instance of the proc: scheme, entirely separate from
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/// signals or any other way to restart a process.
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pub ptrace_stop: bool,
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/// A pointer to the signal stack. If this is unset, none of the sigactions can be anything
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/// else than SIG_DFL, otherwise signals will not be delivered. Userspace is responsible for
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/// setting this.
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pub sigstack: Option<usize>,
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/// An even hackier way to pass the return entry point and stack pointer to new contexts while
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/// implementing clone. Before a context has returned to userspace, its IntRegisters cannot be
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/// set since there is no interrupt stack (unless the kernel stack is copied, but that is in my
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/// opinion hackier and less efficient than this (and UB to do in Rust)).
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pub clone_entry: Option<[usize; 2]>,
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pub fmap_ret: Option<Frame>,
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}
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impl Context {
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pub fn new(id: ContextId) -> Result<Context> {
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let this = Context {
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id,
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pgid: id,
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ppid: ContextId::from(0),
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ruid: 0,
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rgid: 0,
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rns: SchemeNamespace::from(0),
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euid: 0,
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egid: 0,
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ens: SchemeNamespace::from(0),
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sigmask: [0; 2],
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umask: 0o022,
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status: Status::Blocked,
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status_reason: "",
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running: false,
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cpu_id: None,
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switch_time: 0,
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cpu_time: 0,
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sched_affinity: None,
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syscall: None,
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syscall_head: Some(RaiiFrame::allocate()?),
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syscall_tail: Some(RaiiFrame::allocate()?),
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waitpid: Arc::new(WaitMap::new()),
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pending: VecDeque::new(),
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wake: None,
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arch: arch::Context::new(),
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kfx: AlignedBox::<[u8; arch::KFX_SIZE], {arch::KFX_ALIGN}>::try_zeroed()?,
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kstack: None,
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ksig: None,
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ksig_restore: false,
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addr_space: None,
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name: Cow::Borrowed(""),
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files: Arc::new(RwLock::new(Vec::new())),
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actions: Self::empty_actions(),
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regs: None,
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ptrace_stop: false,
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sigstack: None,
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clone_entry: None,
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fmap_ret: None,
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};
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Ok(this)
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}
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/// Block the context, and return true if it was runnable before being blocked
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pub fn block(&mut self, reason: &'static str) -> bool {
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if self.status.is_runnable() {
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self.status = Status::Blocked;
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self.status_reason = reason;
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true
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} else {
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false
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}
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}
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pub fn hard_block(&mut self, reason: HardBlockedReason) -> bool {
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if self.status.is_runnable() {
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self.status = Status::HardBlocked { reason };
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true
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} else {
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false
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}
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}
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/// Unblock context, and return true if it was blocked before being marked runnable
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pub fn unblock(&mut self) -> bool {
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if self.status.is_soft_blocked() {
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self.status = Status::Runnable;
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self.status_reason = "";
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if let Some(cpu_id) = self.cpu_id {
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if cpu_id != crate::cpu_id() {
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// Send IPI if not on current CPU
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ipi(IpiKind::Wakeup, IpiTarget::Other);
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}
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}
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true
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} else {
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false
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}
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}
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/// Add a file to the lowest available slot.
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/// Return the file descriptor number or None if no slot was found
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pub fn add_file(&self, file: FileDescriptor) -> Option<FileHandle> {
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self.add_file_min(file, 0)
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}
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/// Add a file to the lowest available slot greater than or equal to min.
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/// Return the file descriptor number or None if no slot was found
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pub fn add_file_min(&self, file: FileDescriptor, min: usize) -> Option<FileHandle> {
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let mut files = self.files.write();
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for (i, file_option) in files.iter_mut().enumerate() {
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if file_option.is_none() && i >= min {
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*file_option = Some(file);
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return Some(FileHandle::from(i));
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}
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}
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let len = files.len();
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if len < super::CONTEXT_MAX_FILES {
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if len >= min {
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files.push(Some(file));
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Some(FileHandle::from(len))
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} else {
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drop(files);
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self.insert_file(FileHandle::from(min), file)
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}
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} else {
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None
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}
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}
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/// Get a file
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pub fn get_file(&self, i: FileHandle) -> Option<FileDescriptor> {
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let files = self.files.read();
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if i.into() < files.len() {
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files[i.into()].clone()
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} else {
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None
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}
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}
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/// Insert a file with a specific handle number. This is used by dup2
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/// Return the file descriptor number or None if the slot was not empty, or i was invalid
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pub fn insert_file(&self, i: FileHandle, file: FileDescriptor) -> Option<FileHandle> {
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let mut files = self.files.write();
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if i.into() < super::CONTEXT_MAX_FILES {
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while i.into() >= files.len() {
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files.push(None);
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}
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if files[i.into()].is_none() {
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files[i.into()] = Some(file);
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Some(i)
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} else {
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None
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}
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} else {
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None
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}
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}
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/// Remove a file
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// TODO: adjust files vector to smaller size if possible
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pub fn remove_file(&self, i: FileHandle) -> Option<FileDescriptor> {
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let mut files = self.files.write();
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if i.into() < files.len() {
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files[i.into()].take()
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} else {
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None
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}
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}
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pub fn addr_space(&self) -> Result<&Arc<RwLock<AddrSpace>>> {
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self.addr_space.as_ref().ok_or(Error::new(ESRCH))
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}
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pub fn set_addr_space(&mut self, addr_space: Arc<RwLock<AddrSpace>>) -> Option<Arc<RwLock<AddrSpace>>> {
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if self.id == super::context_id() {
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unsafe { addr_space.read().table.utable.make_current(); }
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}
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self.addr_space.replace(addr_space)
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}
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pub fn empty_actions() -> Arc<RwLock<Vec<(SigAction, usize)>>> {
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Arc::new(RwLock::new(vec![(
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SigAction {
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sa_handler: unsafe { mem::transmute(SIG_DFL) },
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sa_mask: [0; 2],
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sa_flags: SigActionFlags::empty(),
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},
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0
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); 128]))
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}
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|
}
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|
|
|
/// Wrapper struct for borrowing the syscall head or tail buf.
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|
#[derive(Debug)]
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|
pub struct BorrowedHtBuf {
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inner: Option<RaiiFrame>,
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head_and_not_tail: bool,
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}
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impl BorrowedHtBuf {
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pub fn head() -> Result<Self> {
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Ok(Self {
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inner: Some(context::current()?.write().syscall_head.take().ok_or(Error::new(EAGAIN))?),
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head_and_not_tail: true,
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})
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}
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pub fn tail() -> Result<Self> {
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Ok(Self {
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inner: Some(context::current()?.write().syscall_tail.take().ok_or(Error::new(EAGAIN))?),
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head_and_not_tail: false,
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})
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}
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pub fn buf(&self) -> &[u8; PAGE_SIZE] {
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unsafe { &*(RmmA::phys_to_virt(self.inner.as_ref().expect("must succeed").get().start_address()).data() as *const [u8; PAGE_SIZE]) }
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}
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pub fn buf_mut(&mut self) -> &mut [u8; PAGE_SIZE] {
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unsafe { &mut *(RmmA::phys_to_virt(self.inner.as_mut().expect("must succeed").get().start_address()).data() as *mut [u8; PAGE_SIZE]) }
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}
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pub fn frame(&self) -> Frame {
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self.inner.as_ref().expect("must succeed").get()
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}
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/*
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pub fn use_for_slice(&mut self, raw: UserSlice) -> Result<Option<&[u8]>> {
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if raw.len() > self.buf().len() {
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return Ok(None);
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}
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|
raw.copy_to_slice(&mut self.buf_mut()[..raw.len()])?;
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Ok(Some(&self.buf()[..raw.len()]))
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|
}
|
|
pub fn use_for_string(&mut self, raw: UserSlice) -> Result<&str> {
|
|
let slice = self.use_for_slice(raw)?.ok_or(Error::new(ENAMETOOLONG))?;
|
|
core::str::from_utf8(slice).map_err(|_| Error::new(EINVAL))
|
|
}
|
|
*/
|
|
pub unsafe fn use_for_struct<T>(&mut self) -> Result<&mut T> {
|
|
if mem::size_of::<T>() > PAGE_SIZE || mem::align_of::<T>() > PAGE_SIZE {
|
|
return Err(Error::new(EINVAL));
|
|
}
|
|
self.buf_mut().fill(0_u8);
|
|
Ok(unsafe { &mut *self.buf_mut().as_mut_ptr().cast() })
|
|
}
|
|
}
|
|
impl Drop for BorrowedHtBuf {
|
|
fn drop(&mut self) {
|
|
let Ok(context) = context::current() else {
|
|
return;
|
|
};
|
|
let Some(inner) = self.inner.take() else {
|
|
return;
|
|
};
|
|
match context.write() {
|
|
mut context => {
|
|
(if self.head_and_not_tail { &mut context.syscall_head } else { &mut context.syscall_tail }).get_or_insert(inner);
|
|
}
|
|
}
|
|
}
|
|
}
|