Jika/redox-kernel
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Support modifying processes' sigactions.

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This is, other than vfork, the last piece of functionality that the
previous clone() offered (CLONE_SIGHAND) which previously was not
implemented.
This commit is contained in:
4lDO2
2022-07-18 14:06:07 +02:00
parent b766501896
commit 308c2cc711
4 changed files with 67 additions and 34 deletions
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19
src/context/context.rs
View File

@@ -368,14 +368,7 @@ impl Context {
name: Arc::new(RwLock::new(String::new().into_boxed_str())),
cwd: Arc::new(RwLock::new(String::new())),
files: Arc::new(RwLock::new(Vec::new())),
actions: Arc::new(RwLock::new(vec![(
SigAction {
sa_handler: unsafe { mem::transmute(SIG_DFL) },
sa_mask: [0; 2],
sa_flags: SigActionFlags::empty(),
},
0
); 128])),
actions: Self::empty_actions(),
regs: None,
ptrace_stop: false,
sigstack: None,
@@ -562,4 +555,14 @@ impl Context {
self.addr_space.replace(addr_space)
}
pub fn empty_actions() -> Arc<RwLock<Vec<(SigAction, usize)>>> {
Arc::new(RwLock::new(vec![(
SigAction {
sa_handler: unsafe { mem::transmute(SIG_DFL) },
sa_mask: [0; 2],
sa_flags: SigActionFlags::empty(),
},
0
); 128]))
}
}

3
src/scheme/mod.rs
View File

@@ -303,4 +303,7 @@ pub trait KernelScheme: Scheme + Send + Sync + 'static {
fn as_addrspace(&self, number: usize) -> Result<Arc<RwLock<AddrSpace>>> {
Err(Error::new(EBADF))
}
fn as_sigactions(&self, number: usize) -> Result<Arc<RwLock<Vec<(crate::syscall::data::SigAction, usize)>>>> {
Err(Error::new(EBADF))
}
}

73
src/scheme/proc.rs
View File

@@ -8,7 +8,7 @@ use crate::{
FloatRegisters,
IntRegisters,
EnvRegisters,
data::{Map, PtraceEvent, Stat},
data::{Map, PtraceEvent, SigAction, Stat},
error::*,
flag::*,
scheme::{calc_seek_offset_usize, Scheme},
@@ -141,6 +141,10 @@ enum Operation {
// TODO: Remove this once cross-scheme links are merged. That would allow acquiring a new
// FD to access the file descriptor behind grants.
GrantHandle { description: Arc<RwLock<FileDescription>> },
Sigactions(Arc<RwLock<Vec<(SigAction, usize)>>>),
CurrentSigactions,
AwaitingSigactionsChange(Arc<RwLock<Vec<(SigAction, usize)>>>),
}
#[derive(Clone, Copy, PartialEq, Eq)]
enum Attr {
@@ -150,7 +154,7 @@ enum Attr {
}
impl Operation {
fn needs_child_process(&self) -> bool {
matches!(self, Self::Memory { .. } | Self::Regs(_) | Self::Trace | Self::Filetable { .. } | Self::AddrSpace { .. } | Self::CurrentAddrSpace | Self::CurrentFiletable)
matches!(self, Self::Memory { .. } | Self::Regs(_) | Self::Trace | Self::Filetable { .. } | Self::AddrSpace { .. } | Self::CurrentAddrSpace | Self::CurrentFiletable | Self::Sigactions(_) | Self::CurrentSigactions | Self::AwaitingSigactionsChange(_))
}
fn needs_root(&self) -> bool {
matches!(self, Self::Attr(_))
@@ -286,7 +290,7 @@ impl ProcScheme {
let operation = match operation_str {
Some("mem") => Operation::Memory { addrspace: current_addrspace()? },
Some("addrspace") => Operation::AddrSpace { addrspace: current_addrspace()? },
Some("filetable") => Operation::Filetable { filetable: Arc::clone(&context::contexts().current().ok_or(Error::new(ESRCH))?.read().files) },
Some("filetable") => Operation::Filetable { filetable: Arc::clone(&context::current()?.read().files) },
Some("current-addrspace") => Operation::CurrentAddrSpace,
Some("current-filetable") => Operation::CurrentFiletable,
Some("regs/float") => Operation::Regs(RegsKind::Float),
@@ -300,6 +304,8 @@ impl ProcScheme {
Some("uid") => Operation::Attr(Attr::Uid),
Some("gid") => Operation::Attr(Attr::Gid),
Some("open_via_dup") => Operation::OpenViaDup,
Some("sigactions") => Operation::Sigactions(Arc::clone(&context::current()?.read().actions)),
Some("current-sigactions") => Operation::CurrentSigactions,
_ => return Err(Error::new(EINVAL))
};
@@ -420,6 +426,15 @@ impl Scheme for ProcScheme {
handle.info.clone()
};
let handle = |operation, data| Handle {
info: Info {
flags: 0,
pid: info.pid,
operation,
},
data,
};
self.new_handle(match info.operation {
Operation::OpenViaDup => {
let (uid, gid) = match &*context::contexts().current().ok_or(Error::new(ESRCH))?.read() {
@@ -428,7 +443,7 @@ impl Scheme for ProcScheme {
return self.open_inner(info.pid, Some(core::str::from_utf8(buf).map_err(|_| Error::new(EINVAL))?).filter(|s| !s.is_empty()), O_RDWR | O_CLOEXEC, uid, gid);
},
Operation::Filetable { filetable } => {
Operation::Filetable { ref filetable } => {
// TODO: Maybe allow userspace to either copy or transfer recently dupped file
// descriptors between file tables.
if buf != b"copy" {
@@ -436,16 +451,9 @@ impl Scheme for ProcScheme {
}
let new_filetable = Arc::try_new(RwLock::new(filetable.read().clone())).map_err(|_| Error::new(ENOMEM))?;
Handle {
info: Info {
flags: 0,
pid: info.pid,
operation: Operation::Filetable { filetable: new_filetable },
},
data: OperationData::Other,
}
handle(Operation::Filetable { filetable: new_filetable }, OperationData::Other)
}
Operation::AddrSpace { addrspace } => {
Operation::AddrSpace { ref addrspace } => {
let (operation, is_mem) = match buf {
// TODO: Better way to obtain new empty address spaces, perhaps using SYS_OPEN. But
// in that case, what scheme?
@@ -462,14 +470,16 @@ impl Scheme for ProcScheme {
_ => return Err(Error::new(EINVAL)),
};
Handle {
info: Info {
flags: 0,
pid: info.pid,
operation,
},
data: if is_mem { OperationData::Memory(MemData { offset: VirtualAddress::new(0) }) } else { OperationData::Offset(0) },
}
handle(operation, if is_mem { OperationData::Memory(MemData { offset: VirtualAddress::new(0) }) } else { OperationData::Offset(0) })
}
Operation::Sigactions(ref sigactions) => {
let new = match buf {
b"empty" => Context::empty_actions(),
b"copy" => Arc::new(RwLock::new(sigactions.read().clone())),
_ => return Err(Error::new(EINVAL)),
};
handle(Operation::Sigactions(new), OperationData::Other)
}
_ => return Err(Error::new(EINVAL)),
})
@@ -991,6 +1001,7 @@ impl Scheme for ProcScheme {
Ok(buf.len())
}
Operation::Filetable { .. } => return Err(Error::new(EBADF)),
Operation::CurrentFiletable => {
let filetable_fd = usize::from_ne_bytes(<[u8; mem::size_of::<usize>()]>::try_from(buf).map_err(|_| Error::new(EINVAL))?);
let (hopefully_this_scheme, number) = extract_scheme_number(filetable_fd)?;
@@ -1014,6 +1025,13 @@ impl Scheme for ProcScheme {
Ok(3 * mem::size_of::<usize>())
}
Operation::CurrentSigactions => {
let sigactions_fd = usize::from_ne_bytes(<[u8; mem::size_of::<usize>()]>::try_from(buf).map_err(|_| Error::new(EINVAL))?);
let (hopefully_this_scheme, number) = extract_scheme_number(sigactions_fd)?;
let sigactions = hopefully_this_scheme.as_sigactions(number)?;
self.handles.write().get_mut(&id).ok_or(Error::new(EBADF))?.info.operation = Operation::AwaitingSigactionsChange(sigactions);
Ok(mem::size_of::<usize>())
}
_ => return Err(Error::new(EBADF)),
}
}
@@ -1059,8 +1077,10 @@ impl Scheme for ProcScheme {
Operation::Attr(Attr::Gid) => "gid",
Operation::Filetable { .. } => "filetable",
Operation::AddrSpace { .. } => "addrspace",
Operation::Sigactions(_) => "sigactions",
Operation::CurrentAddrSpace => "current-addrspace",
Operation::CurrentFiletable => "current-filetable",
Operation::CurrentSigactions => "current-sigactions",
Operation::OpenViaDup => "open-via-dup",
_ => return Err(Error::new(EOPNOTSUPP)),
@@ -1124,6 +1144,10 @@ impl Scheme for ProcScheme {
context.files = new;
Ok(())
})?,
Operation::AwaitingSigactionsChange(new) => with_context_mut(handle.info.pid, |context: &mut Context| {
context.actions = new;
Ok(())
})?,
Operation::Trace => {
ptrace::close_session(handle.info.pid);
@@ -1171,6 +1195,13 @@ impl KernelScheme for ProcScheme {
Err(Error::new(EBADF))
}
}
fn as_sigactions(&self, number: usize) -> Result<Arc<RwLock<Vec<(crate::syscall::data::SigAction, usize)>>>> {
if let Operation::Sigactions(ref sigactions) = self.handles.read().get(&number).ok_or(Error::new(EBADF))?.info.operation {
Ok(Arc::clone(sigactions))
} else {
Err(Error::new(EBADF))
}
}
}
extern "C" fn clone_handler() {
let context_lock = Arc::clone(context::contexts().current().expect("expected the current context to be set in a spawn closure"));

6
src/syscall/process.rs
View File

@@ -65,11 +65,7 @@ pub fn exit(status: usize) -> ! {
ptrace::breakpoint_callback(PTRACE_STOP_EXIT, Some(ptrace_event!(PTRACE_STOP_EXIT, status)));
{
let context_lock = {
let contexts = context::contexts();
let context_lock = contexts.current().ok_or(Error::new(ESRCH)).expect("exit failed to find context");
Arc::clone(&context_lock)
};
let context_lock = context::current().expect("exit failed to find context");
let mut close_files;
let pid = {