From 9c891384ea08755fe117333d3ecbbcd4cab64dbf Mon Sep 17 00:00:00 2001
From: jD91mZM2 <me@krake.one>
Date: Tue, 16 Jun 2020 13:42:04 +0200
Subject: [PATCH] Fix ptrace returning ENODEV when process exists
---
src/ptrace.rs | 25 +++++++++++++++++--------
src/scheme/proc.rs | 3 +++
src/syscall/process.rs | 6 +++---
3 files changed, 23 insertions(+), 11 deletions(-)
diff --git a/src/ptrace.rs b/src/ptrace.rs
index 7029d84..90ca718 100644
--- a/src/ptrace.rs
+++ b/src/ptrace.rs
@@ -112,7 +112,11 @@ impl Session {
F: FnOnce(&Session) -> Result<T>,
{
let sessions = sessions();
- let session = sessions.get(&pid).ok_or(Error::new(ENODEV))?;
+ let session = sessions.get(&pid).ok_or_else(|| {
+ println!("session doesn't exist - returning ENODEV.");
+ println!("can this ever happen?");
+ Error::new(ENODEV)
+ })?;
callback(session)
}
@@ -160,6 +164,18 @@ pub fn close_session(pid: ContextId) {
if let Some(session) = sessions_mut().remove(&pid) {
session.tracer.notify();
session.tracee.notify();
+ }
+}
+
+/// Wake up the tracer to make sure it catches on that the tracee is dead. This
+/// is different from `close_session` in that it doesn't actually close the
+/// session, and instead waits for the file handle to be closed, where the
+/// session will *actually* be closed. This is partly to ensure ENOSRCH is
+/// returned rather than ENODEV (which occurs when there's no session - should
+/// never really happen).
+pub fn close_tracee(pid: ContextId) {
+ if let Some(session) = sessions().get(&pid) {
+ session.tracer.notify();
let data = session.data.lock();
proc_trigger_event(data.file_id, EVENT_READ);
@@ -250,13 +266,6 @@ pub fn wait(pid: ContextId) -> Result<()> {
}
}
- let contexts = context::contexts();
- let context = contexts.get(pid).ok_or(Error::new(ESRCH))?;
- let context = context.read();
- if let Status::Exited(_) = context.status {
- return Err(Error::new(ESRCH));
- }
-
Ok(())
}
diff --git a/src/scheme/proc.rs b/src/scheme/proc.rs
index f80f166..64346ee 100644
--- a/src/scheme/proc.rs
+++ b/src/scheme/proc.rs
@@ -374,6 +374,9 @@ impl Scheme for ProcScheme {
ptrace::wait(handle.info.pid)?;
}
+ // Check if context exists
+ with_context(handle.info.pid, |_| Ok(()))?;
+
// Read events
let slice = unsafe {
slice::from_raw_parts_mut(
diff --git a/src/syscall/process.rs b/src/syscall/process.rs
index cf1737b..18de7f2 100644
--- a/src/syscall/process.rs
+++ b/src/syscall/process.rs
@@ -1065,6 +1065,8 @@ pub fn fexec(fd: FileHandle, arg_ptrs: &[[usize; 2]], var_ptrs: &[[usize; 2]]) -
}
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();
@@ -1072,8 +1074,6 @@ pub fn exit(status: usize) -> ! {
Arc::clone(&context_lock)
};
- ptrace::breakpoint_callback(PTRACE_STOP_EXIT, Some(ptrace_event!(PTRACE_STOP_EXIT, status)));
-
let mut close_files = Vec::new();
let pid = {
let mut context = context_lock.write();
@@ -1152,7 +1152,7 @@ pub fn exit(status: usize) -> ! {
}
// Alert any tracers waiting of this process
- ptrace::close_session(pid);
+ ptrace::close_tracee(pid);
if pid == ContextId::from(1) {
println!("Main kernel thread exited with status {:X}", status);
--
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