virtualizationmanager/src/debug_config.rs - android_packages_modules_Virtualization - Gitiles

 // Copyright 2023, The Android Open Source Project
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.

 //! Functions for AVF debug policy and debug level

 use android_system_virtualizationservice::aidl::android::system::virtualizationservice::{
     VirtualMachineAppConfig::DebugLevel::DebugLevel,
 };
 use anyhow::{anyhow, Context, Error, Result};
 use std::fs;
 use std::io::ErrorKind;
 use std::path::{Path, PathBuf};
 use std::ffi::{CString, NulError};
 use log::{warn, info};
 use rustutils::system_properties;
 use libfdt::{Fdt, FdtError};
 use lazy_static::lazy_static;

 const CUSTOM_DEBUG_POLICY_OVERLAY_SYSPROP: &str =
     "hypervisor.virtualizationmanager.debug_policy.path";
 const DEVICE_TREE_EMPTY_TREE_SIZE_BYTES: usize = 100; // rough estimation.

 struct DPPath {
     node_path: CString,
     prop_name: CString,
 }

 impl DPPath {
     fn new(node_path: &str, prop_name: &str) -> Result<Self, NulError> {
         Ok(Self { node_path: CString::new(node_path)?, prop_name: CString::new(prop_name)? })
     }

     fn to_path(&self) -> PathBuf {
         // unwrap() is safe for to_str() because node_path and prop_name were &str.
         PathBuf::from(
             [
                 "/sys/firmware/devicetree/base",
                 self.node_path.to_str().unwrap(),
                 "/",
                 self.prop_name.to_str().unwrap(),
             ]
             .concat(),
         )
     }
 }

 lazy_static! {
     static ref DP_LOG_PATH: DPPath = DPPath::new("/avf/guest/common", "log").unwrap();
     static ref DP_RAMDUMP_PATH: DPPath = DPPath::new("/avf/guest/common", "ramdump").unwrap();
     static ref DP_ADB_PATH: DPPath = DPPath::new("/avf/guest/microdroid", "adb").unwrap();
 }

 /// Get debug policy value in bool. It's true iff the value is explicitly set to <1>.
 fn get_debug_policy_bool(path: &Path) -> Result<bool> {
     let value = match fs::read(path) {
         Ok(value) => value,
         Err(error) if error.kind() == ErrorKind::NotFound => return Ok(false),
         Err(error) => Err(error).with_context(|| format!("Failed to read {path:?}"))?,
     };

     // DT spec uses big endian although Android is always little endian.
     match u32::from_be_bytes(value.try_into().map_err(|_| anyhow!("Malformed value in {path:?}"))?)
     {
         0 => Ok(false),
         1 => Ok(true),
         value => Err(anyhow!("Invalid value {value} in {path:?}")),
     }
 }

 /// Get property value in bool. It's true iff the value is explicitly set to <1>.
 /// It takes path as &str instead of &Path, because we don't want OsStr.
 fn get_fdt_prop_bool(fdt: &Fdt, path: &DPPath) -> Result<bool> {
     let (node_path, prop_name) = (&path.node_path, &path.prop_name);
     let node = match fdt.node(node_path) {
         Ok(Some(node)) => node,
         Err(error) if error != FdtError::NotFound => Err(error)
             .map_err(Error::msg)
             .with_context(|| format!("Failed to get node {node_path:?}"))?,
         _ => return Ok(false),
     };

     match node.getprop_u32(prop_name) {
         Ok(Some(0)) => Ok(false),
         Ok(Some(1)) => Ok(true),
         Ok(Some(_)) => Err(anyhow!("Invalid prop value {prop_name:?} in node {node_path:?}")),
         Err(error) if error != FdtError::NotFound => Err(error)
             .map_err(Error::msg)
             .with_context(|| format!("Failed to get prop {prop_name:?}")),
         _ => Ok(false),
     }
 }

 /// Fdt with owned vector.
 struct OwnedFdt {
     buffer: Vec<u8>,
 }

 impl OwnedFdt {
     fn from_overlay_onto_new_fdt(overlay_file_path: &Path) -> Result<Self> {
         let mut overlay_buf = match fs::read(overlay_file_path) {
             Ok(fdt) => fdt,
             Err(error) if error.kind() == ErrorKind::NotFound => Default::default(),
             Err(error) => {
                 Err(error).with_context(|| format!("Failed to read {overlay_file_path:?}"))?
             }
         };

         let overlay_buf_size = overlay_buf.len();

         let fdt_estimated_size = overlay_buf_size + DEVICE_TREE_EMPTY_TREE_SIZE_BYTES;
         let mut fdt_buf = vec![0_u8; fdt_estimated_size];
         let fdt = Fdt::create_empty_tree(fdt_buf.as_mut_slice())
             .map_err(Error::msg)
             .context("Failed to create an empty device tree")?;

         if !overlay_buf.is_empty() {
             let overlay_fdt = Fdt::from_mut_slice(overlay_buf.as_mut_slice())
                 .map_err(Error::msg)
                 .with_context(|| "Malformed {overlay_file_path:?}")?;

             // SAFETY: Return immediately if error happens. Damaged fdt_buf and fdt are discarded.
             unsafe {
                 fdt.apply_overlay(overlay_fdt).map_err(Error::msg).with_context(|| {
                     "Failed to overlay {overlay_file_path:?} onto empty device tree"
                 })?;
             }
         }

         Ok(Self { buffer: fdt_buf })
     }

     fn as_fdt(&self) -> &Fdt {
         // SAFETY: Checked validity of buffer when instantiate.
         unsafe { Fdt::unchecked_from_slice(&self.buffer) }
     }
 }

 /// Debug configurations for both debug level and debug policy
 #[derive(Debug)]
 pub struct DebugConfig {
     pub debug_level: DebugLevel,
     debug_policy_log: bool,
     debug_policy_ramdump: bool,
     debug_policy_adb: bool,
 }

 impl DebugConfig {
     pub fn new(debug_level: DebugLevel) -> Self {
         match system_properties::read(CUSTOM_DEBUG_POLICY_OVERLAY_SYSPROP).unwrap_or_default() {
             Some(path) if !path.is_empty() => {
                 match Self::from_custom_debug_overlay_policy(debug_level, Path::new(&path)) {
                     Ok(debug_config) => {
                         info!("Loaded custom debug policy overlay {path}: {debug_config:?}");
                         return debug_config;
                     }
                     Err(err) => warn!("Failed to load custom debug policy overlay {path}: {err:?}"),
                 };
             }
             _ => {
                 match Self::from_host(debug_level) {
                     Ok(debug_config) => {
                         info!("Loaded debug policy from host OS: {debug_config:?}");
                         return debug_config;
                     }
                     Err(err) => warn!("Failed to load debug policy from host OS: {err:?}"),
                 };
             }
         }

         info!("Debug policy is disabled");
         Self {
             debug_level,
             debug_policy_log: false,
             debug_policy_ramdump: false,
             debug_policy_adb: false,
         }
     }

     /// Get whether console output should be configred for VM to leave console and adb log.
     /// Caller should create pipe and prepare for receiving VM log with it.
     pub fn should_prepare_console_output(&self) -> bool {
         self.debug_level != DebugLevel::NONE || self.debug_policy_log || self.debug_policy_adb
     }

     /// Get whether debug apexes (MICRODROID_REQUIRED_APEXES_DEBUG) are required.
     pub fn should_include_debug_apexes(&self) -> bool {
         self.debug_level != DebugLevel::NONE || self.debug_policy_adb
     }

     /// Decision to support ramdump
     pub fn is_ramdump_needed(&self) -> bool {
         self.debug_level != DebugLevel::NONE || self.debug_policy_ramdump
     }

     // TODO: Remove this code path in user build for removing libfdt depenency.
     fn from_custom_debug_overlay_policy(debug_level: DebugLevel, path: &Path) -> Result<Self> {
         match OwnedFdt::from_overlay_onto_new_fdt(path) {
             Ok(fdt) => Ok(Self {
                 debug_level,
                 debug_policy_log: get_fdt_prop_bool(fdt.as_fdt(), &DP_LOG_PATH)?,
                 debug_policy_ramdump: get_fdt_prop_bool(fdt.as_fdt(), &DP_RAMDUMP_PATH)?,
                 debug_policy_adb: get_fdt_prop_bool(fdt.as_fdt(), &DP_ADB_PATH)?,
             }),
             Err(err) => Err(err),
         }
     }

     fn from_host(debug_level: DebugLevel) -> Result<Self> {
         Ok(Self {
             debug_level,
             debug_policy_log: get_debug_policy_bool(&DP_LOG_PATH.to_path())?,
             debug_policy_ramdump: get_debug_policy_bool(&DP_RAMDUMP_PATH.to_path())?,
             debug_policy_adb: get_debug_policy_bool(&DP_ADB_PATH.to_path())?,
         })
     }
 }

 #[cfg(test)]
 mod tests {
     use super::*;
     use anyhow::ensure;

     fn can_set_sysprop() -> bool {
         if let Ok(Some(value)) = system_properties::read("ro.build.type") {
             return "user".eq(&value);
         }
         false // if we're in doubt, skip test.
     }

     #[test]
     fn test_read_avf_debug_policy_with_adb() -> Result<()> {
         let debug_config = DebugConfig::from_custom_debug_overlay_policy(
             DebugLevel::FULL,
             "avf_debug_policy_with_adb.dtbo".as_ref(),
         )
         .unwrap();

         assert_eq!(DebugLevel::FULL, debug_config.debug_level);
         assert!(!debug_config.debug_policy_log);
         assert!(!debug_config.debug_policy_ramdump);
         assert!(debug_config.debug_policy_adb);

         Ok(())
     }

     #[test]
     fn test_read_avf_debug_policy_without_adb() -> Result<()> {
         let debug_config = DebugConfig::from_custom_debug_overlay_policy(
             DebugLevel::FULL,
             "avf_debug_policy_without_adb.dtbo".as_ref(),
         )
         .unwrap();

         assert_eq!(DebugLevel::FULL, debug_config.debug_level);
         assert!(!debug_config.debug_policy_log);
         assert!(!debug_config.debug_policy_ramdump);
         assert!(!debug_config.debug_policy_adb);

         Ok(())
     }

     #[test]
     fn test_invalid_sysprop_disables_debug_policy() -> Result<()> {
         let debug_config = DebugConfig::from_custom_debug_overlay_policy(
             DebugLevel::NONE,
             "/a/does/not/exist/path.dtbo".as_ref(),
         )
         .unwrap();

         assert_eq!(DebugLevel::NONE, debug_config.debug_level);
         assert!(!debug_config.debug_policy_log);
         assert!(!debug_config.debug_policy_ramdump);
         assert!(!debug_config.debug_policy_adb);

         Ok(())
     }

     fn test_new_with_custom_policy_internal() -> Result<()> {
         let debug_config = DebugConfig::new(DebugLevel::NONE);

         ensure!(debug_config.debug_level == DebugLevel::NONE);
         ensure!(!debug_config.debug_policy_log);
         ensure!(!debug_config.debug_policy_ramdump);
         ensure!(debug_config.debug_policy_adb);

         Ok(())
     }

     #[test]
     fn test_new_with_custom_policy() -> Result<()> {
         if !can_set_sysprop() {
             // Skip test if we can't override sysprop.
             return Ok(());
         }

         // Setup
         let old_sysprop = system_properties::read(CUSTOM_DEBUG_POLICY_OVERLAY_SYSPROP)
             .context("Failed to read existing sysprop")?
             .unwrap_or_default();
         let file_name = "avf_debug_policy_with_adb.dtbo";
         system_properties::write(CUSTOM_DEBUG_POLICY_OVERLAY_SYSPROP, file_name)
             .context("Failed to set sysprop")?;

         // Run test
         let test_result = test_new_with_custom_policy_internal();

         // Clean up.
         system_properties::write(CUSTOM_DEBUG_POLICY_OVERLAY_SYSPROP, &old_sysprop)
             .context("Failed to restore sysprop")?;

         test_result
     }
 }
	// Copyright 2023, The Android Open Source Project
	//
	// Licensed under the Apache License, Version 2.0 (the "License");
	// you may not use this file except in compliance with the License.
	// You may obtain a copy of the License at
	//
	// http://www.apache.org/licenses/LICENSE-2.0
	//
	// Unless required by applicable law or agreed to in writing, software
	// distributed under the License is distributed on an "AS IS" BASIS,
	// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	// See the License for the specific language governing permissions and
	// limitations under the License.

	//! Functions for AVF debug policy and debug level

	use android_system_virtualizationservice::aidl::android::system::virtualizationservice::{
	VirtualMachineAppConfig::DebugLevel::DebugLevel,
	};
	use anyhow::{anyhow, Context, Error, Result};
	use std::fs;
	use std::io::ErrorKind;
	use std::path::{Path, PathBuf};
	use std::ffi::{CString, NulError};
	use log::{warn, info};
	use rustutils::system_properties;
	use libfdt::{Fdt, FdtError};
	use lazy_static::lazy_static;

	const CUSTOM_DEBUG_POLICY_OVERLAY_SYSPROP: &str =
	"hypervisor.virtualizationmanager.debug_policy.path";
	const DEVICE_TREE_EMPTY_TREE_SIZE_BYTES: usize = 100; // rough estimation.

	struct DPPath {
	node_path: CString,
	prop_name: CString,
	}

	impl DPPath {
	fn new(node_path: &str, prop_name: &str) -> Result<Self, NulError> {
	Ok(Self { node_path: CString::new(node_path)?, prop_name: CString::new(prop_name)? })
	}

	fn to_path(&self) -> PathBuf {
	// unwrap() is safe for to_str() because node_path and prop_name were &str.
	PathBuf::from(
	[
	"/sys/firmware/devicetree/base",
	self.node_path.to_str().unwrap(),
	"/",
	self.prop_name.to_str().unwrap(),
	]
	.concat(),
	)
	}
	}

	lazy_static! {
	static ref DP_LOG_PATH: DPPath = DPPath::new("/avf/guest/common", "log").unwrap();
	static ref DP_RAMDUMP_PATH: DPPath = DPPath::new("/avf/guest/common", "ramdump").unwrap();
	static ref DP_ADB_PATH: DPPath = DPPath::new("/avf/guest/microdroid", "adb").unwrap();
	}

	/// Get debug policy value in bool. It's true iff the value is explicitly set to <1>.
	fn get_debug_policy_bool(path: &Path) -> Result<bool> {
	let value = match fs::read(path) {
	Ok(value) => value,
	Err(error) if error.kind() == ErrorKind::NotFound => return Ok(false),
	Err(error) => Err(error).with_context(\|\| format!("Failed to read {path:?}"))?,
	};

	// DT spec uses big endian although Android is always little endian.
	match u32::from_be_bytes(value.try_into().map_err(\|_\| anyhow!("Malformed value in {path:?}"))?)
	{
	0 => Ok(false),
	1 => Ok(true),
	value => Err(anyhow!("Invalid value {value} in {path:?}")),
	}
	}

	/// Get property value in bool. It's true iff the value is explicitly set to <1>.
	/// It takes path as &str instead of &Path, because we don't want OsStr.
	fn get_fdt_prop_bool(fdt: &Fdt, path: &DPPath) -> Result<bool> {
	let (node_path, prop_name) = (&path.node_path, &path.prop_name);
	let node = match fdt.node(node_path) {
	Ok(Some(node)) => node,
	Err(error) if error != FdtError::NotFound => Err(error)
	.map_err(Error::msg)
	.with_context(\|\| format!("Failed to get node {node_path:?}"))?,
	_ => return Ok(false),
	};

	match node.getprop_u32(prop_name) {
	Ok(Some(0)) => Ok(false),
	Ok(Some(1)) => Ok(true),
	Ok(Some(_)) => Err(anyhow!("Invalid prop value {prop_name:?} in node {node_path:?}")),
	Err(error) if error != FdtError::NotFound => Err(error)
	.map_err(Error::msg)
	.with_context(\|\| format!("Failed to get prop {prop_name:?}")),
	_ => Ok(false),
	}
	}

	/// Fdt with owned vector.
	struct OwnedFdt {
	buffer: Vec<u8>,
	}

	impl OwnedFdt {
	fn from_overlay_onto_new_fdt(overlay_file_path: &Path) -> Result<Self> {
	let mut overlay_buf = match fs::read(overlay_file_path) {
	Ok(fdt) => fdt,
	Err(error) if error.kind() == ErrorKind::NotFound => Default::default(),
	Err(error) => {
	Err(error).with_context(\|\| format!("Failed to read {overlay_file_path:?}"))?
	}
	};

	let overlay_buf_size = overlay_buf.len();

	let fdt_estimated_size = overlay_buf_size + DEVICE_TREE_EMPTY_TREE_SIZE_BYTES;
	let mut fdt_buf = vec![0_u8; fdt_estimated_size];
	let fdt = Fdt::create_empty_tree(fdt_buf.as_mut_slice())
	.map_err(Error::msg)
	.context("Failed to create an empty device tree")?;

	if !overlay_buf.is_empty() {
	let overlay_fdt = Fdt::from_mut_slice(overlay_buf.as_mut_slice())
	.map_err(Error::msg)
	.with_context(\|\| "Malformed {overlay_file_path:?}")?;

	// SAFETY: Return immediately if error happens. Damaged fdt_buf and fdt are discarded.
	unsafe {
	fdt.apply_overlay(overlay_fdt).map_err(Error::msg).with_context(\|\| {
	"Failed to overlay {overlay_file_path:?} onto empty device tree"
	})?;
	}
	}

	Ok(Self { buffer: fdt_buf })
	}

	fn as_fdt(&self) -> &Fdt {
	// SAFETY: Checked validity of buffer when instantiate.
	unsafe { Fdt::unchecked_from_slice(&self.buffer) }
	}
	}

	/// Debug configurations for both debug level and debug policy
	#[derive(Debug)]
	pub struct DebugConfig {
	pub debug_level: DebugLevel,
	debug_policy_log: bool,
	debug_policy_ramdump: bool,
	debug_policy_adb: bool,
	}

	impl DebugConfig {
	pub fn new(debug_level: DebugLevel) -> Self {
	match system_properties::read(CUSTOM_DEBUG_POLICY_OVERLAY_SYSPROP).unwrap_or_default() {
	Some(path) if !path.is_empty() => {
	match Self::from_custom_debug_overlay_policy(debug_level, Path::new(&path)) {
	Ok(debug_config) => {
	info!("Loaded custom debug policy overlay {path}: {debug_config:?}");
	return debug_config;
	}
	Err(err) => warn!("Failed to load custom debug policy overlay {path}: {err:?}"),
	};
	}
	_ => {
	match Self::from_host(debug_level) {
	Ok(debug_config) => {
	info!("Loaded debug policy from host OS: {debug_config:?}");
	return debug_config;
	}
	Err(err) => warn!("Failed to load debug policy from host OS: {err:?}"),
	};
	}
	}

	info!("Debug policy is disabled");
	Self {
	debug_level,
	debug_policy_log: false,
	debug_policy_ramdump: false,
	debug_policy_adb: false,
	}
	}

	/// Get whether console output should be configred for VM to leave console and adb log.
	/// Caller should create pipe and prepare for receiving VM log with it.
	pub fn should_prepare_console_output(&self) -> bool {
	self.debug_level != DebugLevel::NONE \|\| self.debug_policy_log \|\| self.debug_policy_adb
	}

	/// Get whether debug apexes (MICRODROID_REQUIRED_APEXES_DEBUG) are required.
	pub fn should_include_debug_apexes(&self) -> bool {
	self.debug_level != DebugLevel::NONE \|\| self.debug_policy_adb
	}

	/// Decision to support ramdump
	pub fn is_ramdump_needed(&self) -> bool {
	self.debug_level != DebugLevel::NONE \|\| self.debug_policy_ramdump
	}

	// TODO: Remove this code path in user build for removing libfdt depenency.
	fn from_custom_debug_overlay_policy(debug_level: DebugLevel, path: &Path) -> Result<Self> {
	match OwnedFdt::from_overlay_onto_new_fdt(path) {
	Ok(fdt) => Ok(Self {
	debug_level,
	debug_policy_log: get_fdt_prop_bool(fdt.as_fdt(), &DP_LOG_PATH)?,
	debug_policy_ramdump: get_fdt_prop_bool(fdt.as_fdt(), &DP_RAMDUMP_PATH)?,
	debug_policy_adb: get_fdt_prop_bool(fdt.as_fdt(), &DP_ADB_PATH)?,
	}),
	Err(err) => Err(err),
	}
	}

	fn from_host(debug_level: DebugLevel) -> Result<Self> {
	Ok(Self {
	debug_level,
	debug_policy_log: get_debug_policy_bool(&DP_LOG_PATH.to_path())?,
	debug_policy_ramdump: get_debug_policy_bool(&DP_RAMDUMP_PATH.to_path())?,
	debug_policy_adb: get_debug_policy_bool(&DP_ADB_PATH.to_path())?,
	})
	}
	}

	#[cfg(test)]
	mod tests {
	use super::*;
	use anyhow::ensure;

	fn can_set_sysprop() -> bool {
	if let Ok(Some(value)) = system_properties::read("ro.build.type") {
	return "user".eq(&value);
	}
	false // if we're in doubt, skip test.
	}

	#[test]
	fn test_read_avf_debug_policy_with_adb() -> Result<()> {
	let debug_config = DebugConfig::from_custom_debug_overlay_policy(
	DebugLevel::FULL,
	"avf_debug_policy_with_adb.dtbo".as_ref(),
	)
	.unwrap();

	assert_eq!(DebugLevel::FULL, debug_config.debug_level);
	assert!(!debug_config.debug_policy_log);
	assert!(!debug_config.debug_policy_ramdump);
	assert!(debug_config.debug_policy_adb);

	Ok(())
	}

	#[test]
	fn test_read_avf_debug_policy_without_adb() -> Result<()> {
	let debug_config = DebugConfig::from_custom_debug_overlay_policy(
	DebugLevel::FULL,
	"avf_debug_policy_without_adb.dtbo".as_ref(),
	)
	.unwrap();

	assert_eq!(DebugLevel::FULL, debug_config.debug_level);
	assert!(!debug_config.debug_policy_log);
	assert!(!debug_config.debug_policy_ramdump);
	assert!(!debug_config.debug_policy_adb);

	Ok(())
	}

	#[test]
	fn test_invalid_sysprop_disables_debug_policy() -> Result<()> {
	let debug_config = DebugConfig::from_custom_debug_overlay_policy(
	DebugLevel::NONE,
	"/a/does/not/exist/path.dtbo".as_ref(),
	)
	.unwrap();

	assert_eq!(DebugLevel::NONE, debug_config.debug_level);
	assert!(!debug_config.debug_policy_log);
	assert!(!debug_config.debug_policy_ramdump);
	assert!(!debug_config.debug_policy_adb);

	Ok(())
	}

	fn test_new_with_custom_policy_internal() -> Result<()> {
	let debug_config = DebugConfig::new(DebugLevel::NONE);

	ensure!(debug_config.debug_level == DebugLevel::NONE);
	ensure!(!debug_config.debug_policy_log);
	ensure!(!debug_config.debug_policy_ramdump);
	ensure!(debug_config.debug_policy_adb);

	Ok(())
	}

	#[test]
	fn test_new_with_custom_policy() -> Result<()> {
	if !can_set_sysprop() {
	// Skip test if we can't override sysprop.
	return Ok(());
	}

	// Setup
	let old_sysprop = system_properties::read(CUSTOM_DEBUG_POLICY_OVERLAY_SYSPROP)
	.context("Failed to read existing sysprop")?
	.unwrap_or_default();
	let file_name = "avf_debug_policy_with_adb.dtbo";
	system_properties::write(CUSTOM_DEBUG_POLICY_OVERLAY_SYSPROP, file_name)
	.context("Failed to set sysprop")?;

	// Run test
	let test_result = test_new_with_custom_policy_internal();

	// Clean up.
	system_properties::write(CUSTOM_DEBUG_POLICY_OVERLAY_SYSPROP, &old_sysprop)
	.context("Failed to restore sysprop")?;

	test_result
	}
	}