shadow_rs/host/managed_thread.rs
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//! A thread of a managed process.
//!
//! This contains the code where the simulator can create or communicate with a managed process.
use std::cell::{Cell, RefCell};
use std::ffi::{CStr, CString};
use std::io::Write;
use std::os::fd::AsRawFd;
use std::os::unix::prelude::OsStrExt;
use std::path::PathBuf;
use std::sync::{atomic, Arc};
use linux_api::errno::Errno;
use linux_api::posix_types::Pid;
use linux_api::sched::CloneFlags;
use linux_api::signal::tgkill;
use log::{debug, error, log_enabled, trace, Level};
use rustix::pipe::PipeFlags;
use rustix::process::WaitOptions;
use shadow_shim_helper_rs::ipc::IPCData;
use shadow_shim_helper_rs::shim_event::{
ShimEventAddThreadReq, ShimEventAddThreadRes, ShimEventSyscall, ShimEventSyscallComplete,
ShimEventToShadow, ShimEventToShim,
};
use shadow_shim_helper_rs::syscall_types::{ForeignPtr, SyscallArgs, SyscallReg};
use shadow_shmem::allocator::ShMemBlock;
use vasi_sync::scchannel::SelfContainedChannelError;
use super::context::ThreadContext;
use super::host::Host;
use super::syscall::condition::SyscallCondition;
use crate::core::worker::{Worker, WORKER_SHARED};
use crate::cshadow;
use crate::host::syscall::handler::SyscallHandler;
use crate::host::syscall::types::{ForeignArrayPtr, SyscallReturn};
use crate::utility::{inject_preloads, syscall, verify_plugin_path, VerifyPluginPathError};
/// The ManagedThread's state after having been allowed to execute some code.
#[derive(Debug)]
#[must_use]
pub enum ResumeResult {
/// Blocked on a SyscallCondition.
Blocked(SyscallCondition),
/// The native thread has exited with the given code.
ExitedThread(i32),
/// The thread's process has exited.
ExitedProcess,
}
pub struct ManagedThread {
ipc_shmem: Arc<ShMemBlock<'static, IPCData>>,
is_running: Cell<bool>,
return_code: Cell<Option<i32>>,
/* holds the event for the most recent call from the plugin/shim */
current_event: RefCell<ShimEventToShadow>,
native_pid: linux_api::posix_types::Pid,
native_tid: linux_api::posix_types::Pid,
// Value storing the current CPU affinity of the thread (more precisely,
// of the native thread backing this thread object). This value will be set
// to AFFINITY_UNINIT if CPU pinning is not enabled or if the thread has
// not yet been pinned to a CPU.
affinity: Cell<i32>,
}
impl ManagedThread {
pub fn native_pid(&self) -> linux_api::posix_types::Pid {
self.native_pid
}
pub fn native_tid(&self) -> linux_api::posix_types::Pid {
self.native_tid
}
/// Make the specified syscall on the native thread.
///
/// Panics if the native thread is dead or dies during the syscall,
/// including if the syscall itself is SYS_exit or SYS_exit_group.
pub fn native_syscall(&self, ctx: &ThreadContext, n: i64, args: &[SyscallReg]) -> SyscallReg {
let mut syscall_args = SyscallArgs {
number: n,
args: [SyscallReg::from(0u64); 6],
};
syscall_args.args[..args.len()].copy_from_slice(args);
match self.continue_plugin(
ctx.host,
&ShimEventToShim::Syscall(ShimEventSyscall { syscall_args }),
) {
ShimEventToShadow::SyscallComplete(res) => res.retval,
other => panic!("Unexpected response from plugin: {other:?}"),
}
}
pub fn spawn(
plugin_path: &CStr,
argv: Vec<CString>,
envv: Vec<CString>,
strace_file: Option<&std::fs::File>,
log_file: &std::fs::File,
injected_preloads: &[PathBuf],
) -> Result<Self, Errno> {
debug!("spawning new mthread '{plugin_path:?}' with environment '{envv:?}', arguments '{argv:?}'");
let envv = inject_preloads(envv, injected_preloads);
debug!("env after preload injection: {envv:?}");
let ipc_shmem = Arc::new(shadow_shmem::allocator::shmalloc(IPCData::new()));
let child_pid =
Self::spawn_native(plugin_path, argv, envv, strace_file, log_file, &ipc_shmem)?;
// In Linux, the PID is equal to the TID of its first thread.
let native_pid = child_pid;
let native_tid = child_pid;
// Configure the child_pid_watcher to close the IPC channel when the child dies.
{
let worker = WORKER_SHARED.borrow();
let watcher = worker.as_ref().unwrap().child_pid_watcher();
watcher.register_pid(child_pid);
let ipc = ipc_shmem.clone();
watcher.register_callback(child_pid, move |_pid| {
ipc.from_plugin().close_writer();
})
};
trace!(
"waiting for start event from shim with native pid {:?}",
native_pid
);
let start_req = ipc_shmem.from_plugin().receive().unwrap();
match &start_req {
ShimEventToShadow::StartReq(_) => {
// Expected result; shim is ready to initialize.
}
ShimEventToShadow::ProcessDeath => {
// The process died before initializing the shim.
//
// Reap the dead process and return an error.
let status =
rustix::process::waitpid(Some(native_pid.into()), WaitOptions::empty())
.unwrap()
.unwrap();
if status.exit_status() == Some(127) {
// posix_spawn(3):
// > If the child fails in any of the
// > housekeeping steps described below, or fails to
// > execute the desired file, it exits with a status of
// > 127.
debug!("posix_spawn failed to exec the process");
// Assume that execve failed, and return a plausible reason
// why it might have done so.
// TODO: replace our usage of posix_spawn with a custom
// implementation that can return the execve failure code?
return Err(Errno::EPERM);
}
// TODO: handle more gracefully.
// * The native stdout/stderr might have a clue as to
// why the process died. Consider logging a hint to
// check it (currently in the corresponding shimlog), or
// directly capture it and display it here.
// https://github.com/shadow/shadow/issues/3142
// * Consider logging a warning here and continuing on to handle
// the managed process exit normally. e.g. when this happens
// as part of an emulated `execve`, we might want to continue
// the simulation.
panic!("Child process died unexpectedly before initialization: {status:?}");
}
other => panic!("Unexpected result from shim: {other:?}"),
};
Ok(Self {
ipc_shmem,
is_running: Cell::new(true),
return_code: Cell::new(None),
current_event: RefCell::new(start_req),
native_pid,
native_tid,
affinity: Cell::new(cshadow::AFFINITY_UNINIT),
})
}
pub fn resume(
&self,
ctx: &ThreadContext,
syscall_handler: &mut SyscallHandler,
) -> ResumeResult {
debug_assert!(self.is_running());
self.sync_affinity_with_worker();
// Flush any pending writes, e.g. from a previous mthread that exited
// without flushing.
ctx.process.free_unsafe_borrows_flush().unwrap();
loop {
let mut current_event = self.current_event.borrow_mut();
let last_event = *current_event;
*current_event = match last_event {
ShimEventToShadow::StartReq(start_req) => {
// Write the serialized thread shmem handle directly to shim
// memory.
ctx.process
.memory_borrow_mut()
.write(
start_req.thread_shmem_block_to_init,
&ctx.thread.shmem().serialize(),
)
.unwrap();
if !start_req.process_shmem_block_to_init.is_null() {
// Write the serialized process shmem handle directly to
// shim memory.
ctx.process
.memory_borrow_mut()
.write(
start_req.process_shmem_block_to_init,
&ctx.process.shmem().serialize(),
)
.unwrap();
}
if !start_req.initial_working_dir_to_init.is_null() {
// Write the working dir.
let mut mem = ctx.process.memory_borrow_mut();
let mut writer = mem.writer(ForeignArrayPtr::new(
start_req.initial_working_dir_to_init,
start_req.initial_working_dir_to_init_len,
));
writer
.write_all(ctx.process.current_working_dir().to_bytes_with_nul())
.unwrap();
writer.flush().unwrap();
}
// send the message to the shim to call main().
trace!("sending start event code to shim");
self.continue_plugin(ctx.host, &ShimEventToShim::StartRes)
}
ShimEventToShadow::ProcessDeath => {
// The native threads are all dead or zombies. Nothing to do but
// clean up.
self.cleanup_after_exit_initiated();
return ResumeResult::ExitedProcess;
}
ShimEventToShadow::Syscall(syscall) => {
// Emulate the given syscall.
// `exit` is tricky since it only exits the *mthread*, and we don't have a way
// to be notified that the mthread has exited. We have to "fire and forget"
// the command to execute the syscall natively.
//
// TODO: We could use a tid futex in shared memory, as set by
// `set_tid_address`, to block here until the thread has
// actually exited.
if syscall.syscall_args.number == libc::SYS_exit {
let return_code = syscall.syscall_args.args[0].into();
debug!("Short-circuiting syscall exit({return_code})");
self.return_code.set(Some(return_code));
// Tell mthread to go ahead and make the exit syscall itself.
// We *don't* call `_managedthread_continuePlugin` here,
// since that'd release the ShimSharedMemHostLock, and we
// aren't going to get a message back to know when it'd be
// safe to take it again.
self.ipc_shmem
.to_plugin()
.send(ShimEventToShim::SyscallDoNative);
self.cleanup_after_exit_initiated();
return ResumeResult::ExitedThread(return_code);
}
let scr = syscall_handler.syscall(ctx, &syscall.syscall_args).into();
// remove the mthread's old syscall condition since it's no longer needed
ctx.thread.cleanup_syscall_condition();
assert!(self.is_running());
// Flush any writes that legacy C syscallhandlers may have
// made.
ctx.process.free_unsafe_borrows_flush().unwrap();
match scr {
SyscallReturn::Block(b) => {
return ResumeResult::Blocked(unsafe {
SyscallCondition::consume_from_c(b.cond)
})
}
SyscallReturn::Done(d) => self.continue_plugin(
ctx.host,
&ShimEventToShim::SyscallComplete(ShimEventSyscallComplete {
retval: d.retval,
restartable: d.restartable,
}),
),
SyscallReturn::Native => {
self.continue_plugin(ctx.host, &ShimEventToShim::SyscallDoNative)
}
}
}
ShimEventToShadow::AddThreadRes(res) => {
// We get here in the child process after forking.
// Child should have gotten 0 back from its native clone syscall.
assert_eq!(res.clone_res, 0);
// Complete the virtualized clone syscall.
self.continue_plugin(
ctx.host,
&ShimEventToShim::SyscallComplete(ShimEventSyscallComplete {
retval: 0.into(),
restartable: false,
}),
)
}
e @ ShimEventToShadow::SyscallComplete(_) => panic!("Unexpected event: {e:?}"),
};
assert!(self.is_running());
}
}
pub fn handle_process_exit(&self) {
// TODO: Only do this once per process; maybe by moving into `Process`.
WORKER_SHARED
.borrow()
.as_ref()
.unwrap()
.child_pid_watcher()
.unregister_pid(self.native_pid());
self.cleanup_after_exit_initiated();
}
pub fn return_code(&self) -> Option<i32> {
self.return_code.get()
}
pub fn is_running(&self) -> bool {
self.is_running.get()
}
/// Execute the specified `clone` syscall in `self`, and use create a new
/// `ManagedThread` object to manage it. The new thread will be managed
/// by Shadow, and suitable for use with `Thread::wrap_mthread`.
///
/// If the `clone` syscall fails, the native error is returned.
pub fn native_clone(
&self,
ctx: &ThreadContext,
flags: CloneFlags,
child_stack: ForeignPtr<()>,
ptid: ForeignPtr<libc::pid_t>,
ctid: ForeignPtr<libc::pid_t>,
newtls: libc::c_ulong,
) -> Result<ManagedThread, linux_api::errno::Errno> {
let child_ipc_shmem = Arc::new(shadow_shmem::allocator::shmalloc(IPCData::new()));
// Send the IPC block for the new mthread to use.
let clone_res: i64 = match self.continue_plugin(
ctx.host,
&ShimEventToShim::AddThreadReq(ShimEventAddThreadReq {
ipc_block: child_ipc_shmem.serialize(),
flags: flags.bits(),
child_stack,
ptid: ptid.cast::<()>(),
ctid: ctid.cast::<()>(),
newtls,
}),
) {
ShimEventToShadow::AddThreadRes(ShimEventAddThreadRes { clone_res }) => clone_res,
r => panic!("Unexpected result: {r:?}"),
};
let clone_res: SyscallReg = syscall::raw_return_value_to_result(clone_res)?;
let child_native_tid = Pid::from_raw(libc::pid_t::from(clone_res)).unwrap();
trace!("native clone treated tid {child_native_tid:?}");
trace!(
"waiting for start event from shim with native tid {:?}",
child_native_tid
);
let start_req = child_ipc_shmem.from_plugin().receive().unwrap();
match &start_req {
ShimEventToShadow::StartReq(_) => (),
other => panic!("Unexpected result from shim: {other:?}"),
};
let native_pid = if flags.contains(CloneFlags::CLONE_THREAD) {
self.native_pid
} else {
child_native_tid
};
if !flags.contains(CloneFlags::CLONE_THREAD) {
// Child is a new process; register it.
WORKER_SHARED
.borrow()
.as_ref()
.unwrap()
.child_pid_watcher()
.register_pid(native_pid);
}
// Register the child thread's IPC block with the ChildPidWatcher.
{
let child_ipc_shmem = child_ipc_shmem.clone();
WORKER_SHARED
.borrow()
.as_ref()
.unwrap()
.child_pid_watcher()
.register_callback(native_pid, move |_pid| {
child_ipc_shmem.from_plugin().close_writer();
})
};
Ok(Self {
ipc_shmem: child_ipc_shmem,
is_running: Cell::new(true),
return_code: Cell::new(None),
current_event: RefCell::new(start_req),
native_pid,
native_tid: child_native_tid,
// TODO: can we assume it's inherited from the current thread affinity?
affinity: Cell::new(cshadow::AFFINITY_UNINIT),
})
}
#[must_use]
fn continue_plugin(&self, host: &Host, event: &ShimEventToShim) -> ShimEventToShadow {
// Update shared state before transferring control.
host.shim_shmem_lock_borrow_mut().unwrap().max_runahead_time =
Worker::max_event_runahead_time(host);
host.shim_shmem()
.sim_time
.store(Worker::current_time().unwrap(), atomic::Ordering::Relaxed);
// Release lock so that plugin can take it. Reacquired in `wait_for_next_event`.
host.unlock_shmem();
self.ipc_shmem.to_plugin().send(*event);
let event = match self.ipc_shmem.from_plugin().receive() {
Ok(e) => e,
Err(SelfContainedChannelError::WriterIsClosed) => ShimEventToShadow::ProcessDeath,
};
// Reacquire the shared memory lock, now that the shim has yielded control
// back to us.
host.lock_shmem();
// Update time, which may have been incremented in the shim.
let shim_time = host.shim_shmem().sim_time.load(atomic::Ordering::Relaxed);
if log_enabled!(Level::Trace) {
let worker_time = Worker::current_time().unwrap();
if shim_time != worker_time {
trace!(
"Updating time from {worker_time:?} to {shim_time:?} (+{:?})",
shim_time - worker_time
);
}
}
Worker::set_current_time(shim_time);
event
}
/// To be called after we expect the native thread to have exited, or to
/// exit imminently.
fn cleanup_after_exit_initiated(&self) {
if !self.is_running.get() {
return;
}
self.wait_for_native_exit();
trace!("child {:?} exited", self.native_tid());
self.is_running.set(false);
}
/// Wait until the managed thread is no longer running.
fn wait_for_native_exit(&self) {
let native_pid = self.native_pid();
let native_tid = self.native_tid();
// We use `tgkill` and `/proc/x/stat` to detect whether the thread is still running,
// looping until it doesn't.
//
// Alternatively we could use `set_tid_address` or `set_robust_list` to
// be notified on a futex. Those are a bit underdocumented and fragile,
// though. In practice this shouldn't have to loop significantly.
trace!("Waiting for native thread {native_pid:?}.{native_tid:?} to exit");
loop {
if self.ipc_shmem.from_plugin().writer_is_closed() {
// This indicates that the whole process has stopped executing;
// no need to poll the individual thread.
break;
}
match tgkill(native_pid, native_tid, None) {
Err(Errno::ESRCH) => {
trace!("Thread is done exiting; proceeding with cleanup");
break;
}
Err(e) => {
error!("Unexpected tgkill error: {:?}", e);
break;
}
Ok(()) if native_pid == native_tid => {
// Thread leader could be in a zombie state waiting for
// the other threads to exit.
let filename = format!("/proc/{}/stat", native_pid.as_raw_nonzero().get());
let stat = match std::fs::read_to_string(filename) {
Err(e) => {
assert!(e.kind() == std::io::ErrorKind::NotFound);
trace!("tgl {native_pid:?} is fully dead");
break;
}
Ok(s) => s,
};
if stat.contains(") Z") {
trace!("tgl {native_pid:?} is a zombie");
break;
}
// Still alive and in a non-zombie state; continue
}
Ok(()) => {
// Thread is still alive; continue.
}
};
std::thread::yield_now();
}
}
fn sync_affinity_with_worker(&self) {
let current_affinity = scheduler::core_affinity()
.map(|x| i32::try_from(x).unwrap())
.unwrap_or(cshadow::AFFINITY_UNINIT);
self.affinity.set(unsafe {
cshadow::affinity_setProcessAffinity(
self.native_tid().as_raw_nonzero().get(),
current_affinity,
self.affinity.get(),
)
});
}
fn spawn_native(
plugin_path: &CStr,
argv: Vec<CString>,
envv: Vec<CString>,
strace_file: Option<&std::fs::File>,
shimlog_file: &std::fs::File,
shmem_block: &ShMemBlock<IPCData>,
) -> Result<Pid, Errno> {
// Preemptively check for likely reasons that execve might fail.
// In particular we want to ensure that we don't launch a statically
// linked executable, since we'd then deadlock the whole simulation
// waiting for the plugin to initialize.
//
// This is also helpful since we can't retrieve specific `execve` errors
// through `posix_spawn`.
fn map_verify_err(e: VerifyPluginPathError) -> Errno {
match e {
// execve(2): ENOENT The file pathname [...] does not exist.
VerifyPluginPathError::NotFound => Errno::ENOENT,
// execve(2): EACCES The file or a script interpreter is not a regular file.
VerifyPluginPathError::NotFile => Errno::EACCES,
// execve(2): EACCES Execute permission is denied for the file or a script or ELF interpreter.
VerifyPluginPathError::NotExecutable => Errno::EACCES,
// execve(2): ENOEXEC An executable is not in a recognized
// format, is for the wrong architecture, or has some other
// format error that means it cannot be executed.
VerifyPluginPathError::UnknownFileType => Errno::ENOEXEC,
VerifyPluginPathError::NotDynamicallyLinkedElf => Errno::ENOEXEC,
VerifyPluginPathError::IncompatibleInterpreter(e) => map_verify_err(*e),
// execve(2): EACCES Search permission is denied on a component
// of the path prefix of pathname or the name of a script
// interpreter.
VerifyPluginPathError::PathPermissionDenied => Errno::EACCES,
VerifyPluginPathError::UnhandledIoError(_) => {
// Arbitrary error that should be handled by callers.
Errno::ENOEXEC
}
}
}
verify_plugin_path(std::ffi::OsStr::from_bytes(plugin_path.to_bytes()))
.map_err(map_verify_err)?;
// posix_spawn is documented as taking pointers to *mutable* char for argv and
// envv. It *probably* doesn't actually mutate them, but we
// conservatively give it what it asks for. We have to "reconstitute"
// the CString's after the fork + exec to deallocate them.
let argv_ptrs: Vec<*mut i8> = argv
.into_iter()
.map(CString::into_raw)
// the last element of argv must be NULL
.chain(std::iter::once(std::ptr::null_mut()))
.collect();
let envv_ptrs: Vec<*mut i8> = envv
.into_iter()
.map(CString::into_raw)
// the last element of argv must be NULL
.chain(std::iter::once(std::ptr::null_mut()))
.collect();
let mut file_actions: libc::posix_spawn_file_actions_t = shadow_pod::zeroed();
Errno::result_from_libc_errnum(unsafe {
libc::posix_spawn_file_actions_init(&mut file_actions)
})
.unwrap();
// Set up stdin
let (stdin_reader, stdin_writer) = rustix::pipe::pipe_with(PipeFlags::CLOEXEC).unwrap();
Errno::result_from_libc_errnum(unsafe {
libc::posix_spawn_file_actions_adddup2(
&mut file_actions,
stdin_reader.as_raw_fd(),
libc::STDIN_FILENO,
)
})
.unwrap();
// Dup straceFd; the dup'd descriptor won't have O_CLOEXEC set.
//
// Since dup2 is a no-op when the new and old file descriptors are equal, we have
// to arrange to call dup2 twice - first to a temporary descriptor, and then back
// to the original descriptor number.
//
// Here we use STDOUT_FILENO as the temporary descriptor, since we later
// replace that below.
//
// Once we drop support for platforms with glibc older than 2.29, we *could*
// consider taking advantage of a new feature that would let us just use a
// single `posix_spawn_file_actions_adddup2` call with equal descriptors.
// OTOH it's a non-standard extension, and I think ultimately uses the same
// number of syscalls, so it might be better to continue using this slightly
// more awkward method anyway.
// https://github.com/bminor/glibc/commit/805334b26c7e6e83557234f2008497c72176a6cd
// https://austingroupbugs.net/view.php?id=411
if let Some(strace_file) = strace_file {
Errno::result_from_libc_errnum(unsafe {
libc::posix_spawn_file_actions_adddup2(
&mut file_actions,
strace_file.as_raw_fd(),
libc::STDOUT_FILENO,
)
})
.unwrap();
Errno::result_from_libc_errnum(unsafe {
libc::posix_spawn_file_actions_adddup2(
&mut file_actions,
libc::STDOUT_FILENO,
strace_file.as_raw_fd(),
)
})
.unwrap();
}
// set stdout/stderr as the shim log. This also clears the FD_CLOEXEC flag.
Errno::result_from_libc_errnum(unsafe {
libc::posix_spawn_file_actions_adddup2(
&mut file_actions,
shimlog_file.as_raw_fd(),
libc::STDOUT_FILENO,
)
})
.unwrap();
Errno::result_from_libc_errnum(unsafe {
libc::posix_spawn_file_actions_adddup2(
&mut file_actions,
shimlog_file.as_raw_fd(),
libc::STDERR_FILENO,
)
})
.unwrap();
let mut spawn_attr: libc::posix_spawnattr_t = shadow_pod::zeroed();
Errno::result_from_libc_errnum(unsafe { libc::posix_spawnattr_init(&mut spawn_attr) })
.unwrap();
// In versions of glibc before 2.24, we need this to tell posix_spawn
// to use vfork instead of fork. In later versions it's a no-op.
Errno::result_from_libc_errnum(unsafe {
libc::posix_spawnattr_setflags(
&mut spawn_attr,
libc::POSIX_SPAWN_USEVFORK.try_into().unwrap(),
)
})
.unwrap();
let child_pid_res = {
let mut child_pid = -1;
Errno::result_from_libc_errnum(unsafe {
libc::posix_spawn(
&mut child_pid,
plugin_path.as_ptr(),
&file_actions,
&spawn_attr,
argv_ptrs.as_ptr(),
envv_ptrs.as_ptr(),
)
})
.map(|_| Pid::from_raw(child_pid).unwrap_or_else(|| panic!("Invalid pid: {child_pid}")))
};
// Write the serialized shmem descriptor to the stdin pipe. The pipe
// buffer should be large enough that we can write it all without having
// to wait for data to be read.
if child_pid_res.is_ok() {
// we avoid using the rustix write wrapper here, since we can't guarantee
// that all bytes of the serialized shmem block are initd, and hence
// can't safely construct the &[u8] that it wants.
let serialized = shmem_block.serialize();
let serialized_bytes = shadow_pod::as_u8_slice(&serialized);
let written = Errno::result_from_libc_errno(-1, unsafe {
libc::write(
stdin_writer.as_raw_fd(),
serialized_bytes.as_ptr().cast(),
serialized_bytes.len(),
)
})
.unwrap();
// TODO: loop if needed. Shouldn't be in practice, though.
assert_eq!(written, isize::try_from(serialized_bytes.len()).unwrap());
}
Errno::result_from_libc_errnum(unsafe {
libc::posix_spawn_file_actions_destroy(&mut file_actions)
})
.unwrap();
Errno::result_from_libc_errnum(unsafe { libc::posix_spawnattr_destroy(&mut spawn_attr) })
.unwrap();
// Drop the cloned argv and env.
drop(
argv_ptrs
.into_iter()
.filter(|p| !p.is_null())
.map(|p| unsafe { CString::from_raw(p) }),
);
drop(
envv_ptrs
.into_iter()
.filter(|p| !p.is_null())
.map(|p| unsafe { CString::from_raw(p) }),
);
debug!(
"starting process {}, result: {child_pid_res:?}",
plugin_path.to_str().unwrap()
);
child_pid_res
}
/// `ManagedThread` panics if dropped while the underlying process is still running,
/// since otherwise that process could continue writing to shared memory regions
/// that shadow reallocates.
///
/// This method kills the process that `self` belongs to (not just the
/// thread!) and then drops `self`.
pub fn kill_and_drop(self) {
if let Err(err) =
rustix::process::kill_process(self.native_pid().into(), rustix::process::Signal::Kill)
{
log::warn!(
"Couldn't kill managed process {:?}. kill: {:?}",
self.native_pid(),
err
);
}
self.handle_process_exit();
}
}
impl Drop for ManagedThread {
fn drop(&mut self) {
// Dropping while the thread is running is unsound because the running
// thread still has access to shared memory regions that will be
// deallocated, and potentially reallocated for another purpose. The
// running thread accessing a deallocated or repurposed memory region
// can cause numerous problems.
assert!(!self.is_running());
}
}