Cope better with errors in child processes
If a test needs to run in a child process, make it easier to cope if
that child process encounters a failure along the way.
- Add a stringly-typed `Error` to the `run_as` module, which can:
- be serialized and so emitted from child processes
- be constructed from an `anyhow::Error`.
- Add helper macros that construct and `return` an `Error` rather than
directly panicking.
- Add a `recv_or_die()` method that attempts to read a response message
from the child process, but copes with the channel being gone. This
happens if the child has already exited; in this case a final result
message is hopefully available on the `result_reader`.
- Migrate the auth-bound tests to use `Result<(), run_as::Error>`.
Test: keystore2_client_tests auth_bound
Change-Id: Ic306bb272f740a44c0e1d06c948f11435ac3b211
diff --git a/keystore2/test_utils/key_generations.rs b/keystore2/test_utils/key_generations.rs
index c40e944..5e823c2 100644
--- a/keystore2/test_utils/key_generations.rs
+++ b/keystore2/test_utils/key_generations.rs
@@ -393,22 +393,27 @@
}
/// Check for a specific KeyMint error.
-pub fn assert_km_error<T: std::fmt::Debug>(result: &BinderResult<T>, want: ErrorCode) {
- match result {
- Ok(_) => panic!("Expected KeyMint error {want:?}, found success"),
- Err(s) => {
- assert_eq!(
- s.exception_code(),
- ExceptionCode::SERVICE_SPECIFIC,
- "Expected KeyMint service-specific error {want:?}, got {result:?}"
- );
- assert_eq!(
- s.service_specific_error(),
- want.0,
- "Expected KeyMint service-specific error {want:?}, got {result:?}"
- );
+#[macro_export]
+macro_rules! expect_km_error {
+ { $result:expr, $want:expr } => {
+ match $result {
+ Ok(_) => return Err(format!(
+ "{}:{}: Expected KeyMint error {:?}, found success",
+ file!(),
+ line!(),
+ $want
+ ).into()),
+ Err(s) if s.exception_code() == ExceptionCode::SERVICE_SPECIFIC
+ && s.service_specific_error() == $want.0 => {}
+ Err(e) => return Err(format!(
+ "{}:{}: Expected KeyMint service-specific error {:?}, got {e:?}",
+ file!(),
+ line!(),
+ $want
+ ).into()),
}
- }
+
+ };
}
/// Get the value of the given system property, if the given system property doesn't exist
diff --git a/keystore2/test_utils/run_as.rs b/keystore2/test_utils/run_as.rs
index 2cd9fec..14a72be 100644
--- a/keystore2/test_utils/run_as.rs
+++ b/keystore2/test_utils/run_as.rs
@@ -32,12 +32,104 @@
fork, pipe as nix_pipe, read as nix_read, setgid, setuid, write as nix_write, ForkResult, Gid,
Pid, Uid,
};
-use serde::{de::DeserializeOwned, Serialize};
+use serde::{de::DeserializeOwned, Deserialize, Serialize};
use std::io::{Read, Write};
use std::marker::PhantomData;
use std::os::fd::AsRawFd;
use std::os::fd::OwnedFd;
+/// Newtype string error, which can be serialized and transferred out from a sub-process.
+#[derive(Debug, Deserialize, Serialize, PartialEq, Eq)]
+pub struct Error(pub String);
+
+/// Allow ergonomic use of [`anyhow::Error`].
+impl From<anyhow::Error> for Error {
+ fn from(err: anyhow::Error) -> Self {
+ // Use the debug format of [`anyhow::Error`] to include backtrace.
+ Self(format!("{:?}", err))
+ }
+}
+impl From<String> for Error {
+ fn from(val: String) -> Self {
+ Self(val)
+ }
+}
+impl From<&str> for Error {
+ fn from(val: &str) -> Self {
+ Self(val.to_string())
+ }
+}
+
+impl std::fmt::Display for Error {
+ fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+ write!(f, "{}", self.0)
+ }
+}
+
+impl std::error::Error for Error {}
+
+/// Equivalent to the [`assert!`] macro which returns an [`Error`] rather than emitting a panic.
+/// This is useful for test code that is `run_as`, so failures are more accessible.
+#[macro_export]
+macro_rules! expect {
+ ($cond:expr $(,)?) => {{
+ let result = $cond;
+ if !result {
+ return Err($crate::run_as::Error(format!(
+ "{}:{}: check '{}' failed",
+ file!(),
+ line!(),
+ stringify!($cond)
+ )));
+ }
+ }};
+ ($cond:expr, $($arg:tt)+) => {{
+ let result = $cond;
+ if !result {
+ return Err($crate::run_as::Error(format!(
+ "{}:{}: check '{}' failed: {}",
+ file!(),
+ line!(),
+ stringify!($cond),
+ format_args!($($arg)+)
+ )));
+ }
+ }};
+}
+
+/// Equivalent to the [`assert_eq!`] macro which returns an [`Error`] rather than emitting a panic.
+/// This is useful for test code that is `run_as`, so failures are more accessible.
+#[macro_export]
+macro_rules! expect_eq {
+ ($left:expr, $right:expr $(,)?) => {{
+ let left = $left;
+ let right = $right;
+ if left != right {
+ return Err($crate::run_as::Error(format!(
+ "{}:{}: assertion {} == {} failed\n left: {left:?}\n right: {right:?}\n",
+ file!(),
+ line!(),
+ stringify!($left),
+ stringify!($right),
+ )));
+ }
+ }};
+ ($left:expr, $right:expr, $($arg:tt)+) => {{
+ let left = $left;
+ let right = $right;
+ if left != right {
+ return Err($crate::run_as::Error(format!(
+ "{}:{}: assertion {} == {} failed: {}\n left: {left:?}\n right: {right:?}\n",
+ file!(),
+ line!(),
+ stringify!($left),
+ stringify!($right),
+ format_args!($($arg)+)
+ )));
+ }
+ }};
+}
+
fn transition(se_context: selinux::Context, uid: Uid, gid: Gid) {
setgid(gid).expect("Failed to set GID. This test might need more privileges.");
setuid(uid).expect("Failed to set UID. This test might need more privileges.");
@@ -119,31 +211,48 @@
/// Receiving blocks until an object of type T has been read from the channel.
/// Panics if an error occurs during io or deserialization.
pub fn recv(&mut self) -> T {
+ match self.recv_err() {
+ Ok(val) => val,
+ Err(e) => panic!("{e}"),
+ }
+ }
+
+ /// Receives a serializable object from the corresponding ChannelWriter.
+ /// Receiving blocks until an object of type T has been read from the channel.
+ pub fn recv_err(&mut self) -> Result<T, Error> {
let mut size_buffer = [0u8; std::mem::size_of::<usize>()];
match self.0.read(&mut size_buffer).expect("In ChannelReader::recv: Failed to read size.") {
r if r != size_buffer.len() => {
- panic!("In ChannelReader::recv: Failed to read size. Insufficient data: {}", r);
+ return Err(format!(
+ "In ChannelReader::recv: Failed to read size. Insufficient data: {}",
+ r
+ )
+ .into());
}
_ => {}
};
let size = usize::from_be_bytes(size_buffer);
let mut data_buffer = vec![0u8; size];
- match self
- .0
- .read(&mut data_buffer)
- .expect("In ChannelReader::recv: Failed to read serialized data.")
- {
- r if r != data_buffer.len() => {
- panic!(
+ match self.0.read(&mut data_buffer) {
+ Ok(r) if r != data_buffer.len() => {
+ return Err(format!(
"In ChannelReader::recv: Failed to read serialized data. Insufficient data: {}",
r
- );
+ )
+ .into());
}
- _ => {}
+ Ok(_) => {}
+ Err(e) => {
+ return Err(format!(
+ "In ChannelReader::recv: Failed to read serialized data: {e:?}"
+ )
+ .into())
+ }
};
- serde_cbor::from_slice(&data_buffer)
- .expect("In ChannelReader::recv: Failed to deserialize data.")
+ serde_cbor::from_slice(&data_buffer).map_err(|e| {
+ format!("In ChannelReader::recv: Failed to deserialize data: {e:?}").into()
+ })
}
}
@@ -186,6 +295,11 @@
/// Get child result. Panics if the child did not exit with status 0 or if a serialization
/// error occurred.
pub fn get_result(mut self) -> R {
+ self.get_death_result()
+ }
+
+ /// Get child result via a mutable reference.
+ fn get_death_result(&mut self) -> R {
let status =
waitpid(self.pid, None).expect("ChildHandle::wait: Failed while waiting for child.");
match status {
@@ -205,6 +319,31 @@
}
}
+impl<R, M> ChildHandle<Result<R, Error>, M>
+where
+ R: Serialize + DeserializeOwned,
+ M: Serialize + DeserializeOwned,
+{
+ /// Receive a response from the child. If the child has closed the response
+ /// channel, assume it has terminated and read the final result.
+ /// Panics on child failure, but will display the child error value.
+ pub fn recv_or_die(&mut self) -> M {
+ match self.response_reader.recv_err() {
+ Ok(v) => v,
+ Err(_e) => {
+ // We have failed to read from the `response_reader` channel.
+ // Assume this is because the child completed early with an error.
+ match self.get_death_result() {
+ Ok(_) => {
+ panic!("Child completed OK despite failure to read a response!")
+ }
+ Err(e) => panic!("Child failed with:\n{e}"),
+ }
+ }
+ }
+ }
+}
+
impl<R: Serialize + DeserializeOwned, M: Serialize + DeserializeOwned> Drop for ChildHandle<R, M> {
fn drop(&mut self) {
if self.exit_status.is_none() {