From ce3e54438c83d255130900e19bedd9fc69d055a6 Mon Sep 17 00:00:00 2001
From: 4lDO2 <4lDO2@protonmail.com>
Date: Thu, 18 May 2023 13:38:58 +0200
Subject: [PATCH] Release file_op's Arc before Scheme::handle.
This fixes https://gitlab.redox-os.org/redox-os/kernel/-/issues/117.
Redox's signal code switches the kernel stack to a signal stack, and if
that kernel stack runs SIGKILL's exit(), it won't run the Arc destructor
from the original stack.
We should really get rid of this stack-switching mechanism!
---
src/syscall/fs.rs | 27 ++++++++++++---------------
1 file changed, 12 insertions(+), 15 deletions(-)
diff --git a/src/syscall/fs.rs b/src/syscall/fs.rs
index 100214a6..e2c70f26 100644
--- a/src/syscall/fs.rs
+++ b/src/syscall/fs.rs
@@ -13,27 +13,24 @@ use crate::syscall::flag::*;
pub fn file_op(a: usize, fd: FileHandle, c: usize, d: usize) -> Result<usize> {
- let (file, pid, uid, gid) = {
- let contexts = context::contexts();
- let context_lock = contexts.current().ok_or(Error::new(ESRCH))?;
- let context = context_lock.read();
- let file = context.get_file(fd).ok_or(Error::new(EBADF))?;
- (file, context.id, context.euid, context.egid)
+ let (scheme_id, scheme_number, current_cid, current_uid, current_gid) = match context::current()?.read() {
+ // TODO: Avoid semi-expensive Arc::clone by only accessing by reference?
+ ref current => match current.get_file(fd).ok_or(Error::new(EBADF))?.description.read() {
+ ref desc => {
+ (desc.scheme, desc.number, current.id, current.euid, current.egid)
+ }
+ }
};
- let scheme = {
- let schemes = scheme::schemes();
- let scheme = schemes.get(file.description.read().scheme).ok_or(Error::new(EBADF))?;
- Arc::clone(scheme)
- };
+ let scheme = Arc::clone(scheme::schemes().get(scheme_id).ok_or(Error::new(EBADF))?);
let mut packet = Packet {
id: 0,
- pid: pid.into(),
- uid,
- gid,
+ pid: current_cid.into(),
+ uid: current_uid,
+ gid: current_gid,
a,
- b: file.description.read().number,
+ b: scheme_number,
c,
d
};
--
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