From 5492259af9fa82443f072af635d438024428fe1c Mon Sep 17 00:00:00 2001 From: Alyssa Ross Date: Thu, 27 Apr 2023 12:43:57 +0000 Subject: [PATCH] main: reset tty if starting the VM fails When I refactored this to centralise resetting the tty into DeviceManager::drop, I tested that the tty was reset if an error happened on the vmm thread, but not on the main thread. It turns out that if an error happened on the main thread, the process would just exit, so drop handlers on other threads wouldn't get run. To fix this, I've changed start_vmm() to write to the VMM's exit eventfd and then join the thread if an error happens after the vmm thread is started. Fixes: b6feae0a ("vmm: only touch the tty flags if it's being used") Signed-off-by: Alyssa Ross --- src/main.rs | 59 ++++++++++++++++++++++++++++++++------------------ vmm/src/lib.rs | 10 ++++----- vmm/src/vm.rs | 8 +++---- 3 files changed, 47 insertions(+), 30 deletions(-) diff --git a/src/main.rs b/src/main.rs index 27e67d772..d15ff380f 100644 --- a/src/main.rs +++ b/src/main.rs @@ -8,7 +8,7 @@ extern crate event_monitor; use argh::FromArgs; use libc::EFD_NONBLOCK; -use log::LevelFilter; +use log::{warn, LevelFilter}; use option_parser::OptionParser; use seccompiler::SeccompAction; use signal_hook::consts::SIGSYS; @@ -33,6 +33,8 @@ enum Error { #[cfg(feature = "guest_debug")] #[error("Failed to create Debug EventFd: {0}")] CreateDebugEventFd(#[source] std::io::Error), + #[error("Failed to create exit EventFd: {0}")] + CreateExitEventFd(#[source] std::io::Error), #[error("Failed to open hypervisor interface (is hypervisor interface available?): {0}")] CreateHypervisor(#[source] hypervisor::HypervisorError), #[error("Failed to start the VMM thread: {0}")] @@ -509,6 +511,8 @@ fn start_vmm(toplevel: TopLevel) -> Result, Error> { #[cfg(feature = "guest_debug")] let vm_debug_evt = EventFd::new(EFD_NONBLOCK).map_err(Error::CreateDebugEventFd)?; + let exit_evt = EventFd::new(EFD_NONBLOCK).map_err(Error::CreateExitEventFd)?; + let vmm_thread = vmm::start_vmm_thread( env!("CARGO_PKG_VERSION").to_string(), &api_socket_path, @@ -522,33 +526,46 @@ fn start_vmm(toplevel: TopLevel) -> Result, Error> { debug_evt.try_clone().unwrap(), #[cfg(feature = "guest_debug")] vm_debug_evt.try_clone().unwrap(), + exit_evt.try_clone().unwrap(), &seccomp_action, hypervisor, ) .map_err(Error::StartVmmThread)?; - let payload_present = toplevel.kernel.is_some() || toplevel.firmware.is_some(); + let r: Result<(), Error> = (|| { + let payload_present = toplevel.kernel.is_some() || toplevel.firmware.is_some(); - if payload_present { - let vm_params = toplevel.to_vm_params(); - let vm_config = config::VmConfig::parse(vm_params).map_err(Error::ParsingConfig)?; + if payload_present { + let vm_params = toplevel.to_vm_params(); + let vm_config = config::VmConfig::parse(vm_params).map_err(Error::ParsingConfig)?; - // Create and boot the VM based off the VM config we just built. - let sender = api_request_sender.clone(); - vmm::api::vm_create( - api_evt.try_clone().unwrap(), - api_request_sender, - Arc::new(Mutex::new(vm_config)), - ) - .map_err(Error::VmCreate)?; - vmm::api::vm_boot(api_evt.try_clone().unwrap(), sender).map_err(Error::VmBoot)?; - } else if let Some(restore_params) = toplevel.restore { - vmm::api::vm_restore( - api_evt.try_clone().unwrap(), - api_request_sender, - Arc::new(config::RestoreConfig::parse(&restore_params).map_err(Error::ParsingRestore)?), - ) - .map_err(Error::VmRestore)?; + // Create and boot the VM based off the VM config we just built. + let sender = api_request_sender.clone(); + vmm::api::vm_create( + api_evt.try_clone().unwrap(), + api_request_sender, + Arc::new(Mutex::new(vm_config)), + ) + .map_err(Error::VmCreate)?; + vmm::api::vm_boot(api_evt.try_clone().unwrap(), sender).map_err(Error::VmBoot)?; + } else if let Some(restore_params) = toplevel.restore { + vmm::api::vm_restore( + api_evt.try_clone().unwrap(), + api_request_sender, + Arc::new( + config::RestoreConfig::parse(&restore_params).map_err(Error::ParsingRestore)?, + ), + ) + .map_err(Error::VmRestore)?; + } + + Ok(()) + })(); + + if r.is_err() { + if let Err(e) = exit_evt.write(1) { + warn!("writing to exit EventFd: {e}"); + } } vmm_thread diff --git a/vmm/src/lib.rs b/vmm/src/lib.rs index ce5c65d28..9be80f534 100644 --- a/vmm/src/lib.rs +++ b/vmm/src/lib.rs @@ -289,6 +289,7 @@ pub fn start_vmm_thread( #[cfg(feature = "guest_debug")] debug_path: Option, #[cfg(feature = "guest_debug")] debug_event: EventFd, #[cfg(feature = "guest_debug")] vm_debug_event: EventFd, + exit_event: EventFd, seccomp_action: &SeccompAction, hypervisor: Arc, ) -> Result>> { @@ -309,9 +310,8 @@ pub fn start_vmm_thread( .map_err(Error::CreateSeccompFilter)?; let vmm_seccomp_action = seccomp_action.clone(); - let exit_evt = EventFd::new(EFD_NONBLOCK).map_err(Error::EventFdCreate)?; let thread = { - let exit_evt = exit_evt.try_clone().map_err(Error::EventFdClone)?; + let exit_event = exit_event.try_clone().map_err(Error::EventFdClone)?; thread::Builder::new() .name("vmm".to_string()) .spawn(move || { @@ -329,7 +329,7 @@ pub fn start_vmm_thread( vm_debug_event, vmm_seccomp_action, hypervisor, - exit_evt, + exit_event, )?; vmm.setup_signal_handler()?; @@ -350,7 +350,7 @@ pub fn start_vmm_thread( http_api_event, api_sender, seccomp_action, - exit_evt, + exit_event, hypervisor_type, )?; } else if let Some(http_fd) = http_fd { @@ -359,7 +359,7 @@ pub fn start_vmm_thread( http_api_event, api_sender, seccomp_action, - exit_evt, + exit_event, hypervisor_type, )?; } diff --git a/vmm/src/vm.rs b/vmm/src/vm.rs index dfb51ef2d..5723e4915 100644 --- a/vmm/src/vm.rs +++ b/vmm/src/vm.rs @@ -314,10 +314,10 @@ impl VmState { fn valid_transition(self, new_state: VmState) -> Result<()> { match self { VmState::Created => match new_state { - VmState::Created | VmState::Shutdown => { - Err(Error::InvalidStateTransition(self, new_state)) + VmState::Created => Err(Error::InvalidStateTransition(self, new_state)), + VmState::Running | VmState::Paused | VmState::BreakPoint | VmState::Shutdown => { + Ok(()) } - VmState::Running | VmState::Paused | VmState::BreakPoint => Ok(()), }, VmState::Running => match new_state { @@ -2694,7 +2694,7 @@ mod tests { // Check the transitions from Created assert!(state.valid_transition(VmState::Created).is_err()); assert!(state.valid_transition(VmState::Running).is_ok()); - assert!(state.valid_transition(VmState::Shutdown).is_err()); + assert!(state.valid_transition(VmState::Shutdown).is_ok()); assert!(state.valid_transition(VmState::Paused).is_ok()); assert!(state.valid_transition(VmState::BreakPoint).is_ok()); }