loader/bpfloader.rs - android_system_bpf - Gitiles

 /*
  * Copyright (C) 2024 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.
  */

 //! BPF loader for system and vendor applications

 // Enable dead_code until feature flag is removed.
 #![cfg_attr(not(enable_libbpf), allow(dead_code))]

 use android_ids::{AID_ROOT, AID_SYSTEM};
 use android_logger::AndroidLogger;
 use anyhow::{anyhow, ensure};
 use libbpf_rs::{MapCore, ObjectBuilder};
 use libc::{mode_t, S_IRGRP, S_IRUSR, S_IWGRP, S_IWUSR};
 use log::{debug, error, info, Level, LevelFilter, Log, Metadata, Record, SetLoggerError};
 use std::{
     cmp::max,
     env, fs,
     fs::{File, Permissions},
     io::{LineWriter, Write},
     os::fd::FromRawFd,
     os::unix::fs::{chown, PermissionsExt},
     panic,
     path::Path,
     sync::{Arc, Mutex},
 };

 enum KernelLevel {
     // Commented out unused due to rust complaining...
     // EMERG = 0,
     // ALERT = 1,
     // CRIT = 2,
     ERR = 3,
     WARNING = 4,
     // NOTICE = 5,
     INFO = 6,
     DEBUG = 7,
 }

 fn level_to_kern_level(level: &Level) -> u8 {
     let result = match level {
         Level::Error => KernelLevel::ERR,
         Level::Warn => KernelLevel::WARNING,
         Level::Info => KernelLevel::INFO,
         Level::Debug => KernelLevel::DEBUG,
         Level::Trace => KernelLevel::DEBUG,
     };
     result as u8
 }

 /// A logger implementation to enable bpfloader to write to kmsg on error as
 /// bpfloader runs at early init prior to the availability of standard Android
 /// logging. If a crash were to occur, we can disrupt boot, and therefore we
 /// need the ability to access the logs on the serial port.
 pub struct BpfKmsgLogger {
     log_level: LevelFilter,
     tag: String,
     kmsg_writer: Arc<Mutex<Box<dyn Write + Send>>>,
     a_logger: AndroidLogger,
 }

 impl Log for BpfKmsgLogger {
     fn enabled(&self, metadata: &Metadata) -> bool {
         metadata.level() <= self.log_level || self.a_logger.enabled(metadata)
     }

     fn log(&self, record: &Record) {
         if !self.enabled(record.metadata()) {
             return;
         }

         if record.metadata().level() <= self.log_level {
             let mut writer = self.kmsg_writer.lock().unwrap();
             write!(
                 writer,
                 "<{}>{}: {}",
                 level_to_kern_level(&record.level()),
                 self.tag,
                 record.args()
             )
             .unwrap();
             let _ = writer.flush();
         }
         self.a_logger.log(record);
     }

     fn flush(&self) {}
 }

 impl BpfKmsgLogger {
     /// Initialize the logger
     pub fn init(kmsg_file: File) -> Result<(), SetLoggerError> {
         let alog_level = LevelFilter::Info;
         let kmsg_level = LevelFilter::Error;

         let log_config = android_logger::Config::default()
             .with_tag("BpfLoader-rs")
             .with_max_level(alog_level)
             .with_log_buffer(android_logger::LogId::Main)
             .format(|buf, record| writeln!(buf, "{}", record.args()));

         let writer = Box::new(LineWriter::new(kmsg_file)) as Box<dyn Write + Send>;
         log::set_max_level(max(alog_level, kmsg_level));
         log::set_boxed_logger(Box::new(BpfKmsgLogger {
             log_level: kmsg_level,
             tag: "BpfLoader-rs".to_string(),
             kmsg_writer: Arc::new(Mutex::new(writer)),
             a_logger: AndroidLogger::new(log_config),
         }))
     }
 }

 struct MapDesc {
     name: &'static str,
     perms: mode_t,
 }

 struct ProgDesc {
     name: &'static str,
 }

 struct BpfFileDesc {
     filename: &'static str,
     // Warning: setting this to 'true' will cause the system to boot loop if there are any issues
     // loading the bpf program.
     critical: bool,
     owner: u32,
     group: u32,
     maps: &'static [MapDesc],
     progs: &'static [ProgDesc],
 }

 const PERM_GRW: mode_t = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP;
 const PERM_GRO: mode_t = S_IRUSR | S_IWUSR | S_IRGRP;
 const PERM_GWO: mode_t = S_IRUSR | S_IWUSR | S_IWGRP;
 const PERM_UGR: mode_t = S_IRUSR | S_IRGRP;

 const FILE_ARR: &[BpfFileDesc] = &[BpfFileDesc {
     filename: "timeInState.bpf",
     critical: false,
     owner: AID_ROOT,
     group: AID_SYSTEM,
     maps: &[
         MapDesc { name: "cpu_last_pid_map", perms: PERM_GWO },
         MapDesc { name: "cpu_last_update_map", perms: PERM_GWO },
         MapDesc { name: "cpu_policy_map", perms: PERM_GWO },
         MapDesc { name: "freq_to_idx_map", perms: PERM_GWO },
         MapDesc { name: "nr_active_map", perms: PERM_GWO },
         MapDesc { name: "pid_task_aggregation_map", perms: PERM_GWO },
         MapDesc { name: "pid_time_in_state_map", perms: PERM_GRO },
         MapDesc { name: "pid_tracked_hash_map", perms: PERM_GWO },
         MapDesc { name: "pid_tracked_map", perms: PERM_GWO },
         MapDesc { name: "policy_freq_idx_map", perms: PERM_GWO },
         MapDesc { name: "policy_nr_active_map", perms: PERM_GWO },
         MapDesc { name: "total_time_in_state_map", perms: PERM_GRW },
         MapDesc { name: "uid_concurrent_times_map", perms: PERM_GRW },
         MapDesc { name: "uid_last_update_map", perms: PERM_GRW },
         MapDesc { name: "uid_time_in_state_map", perms: PERM_GRW },
     ],
     progs: &[
         ProgDesc { name: "tracepoint_power_cpu_frequency" },
         ProgDesc { name: "tracepoint_sched_sched_process_free" },
         ProgDesc { name: "tracepoint_sched_sched_switch" },
     ],
 }];

 fn libbpf_worker(file_desc: &BpfFileDesc) -> Result<(), anyhow::Error> {
     info!("Loading {}", file_desc.filename);
     let filepath = Path::new("/etc/bpf/").join(file_desc.filename);
     ensure!(filepath.exists(), "File not found {}", filepath.display());
     let filename =
         filepath.file_stem().ok_or_else(|| anyhow!("Failed to parse stem from filename"))?;
     let filename = filename.to_str().ok_or_else(|| anyhow!("Failed to parse filename"))?;

     let mut ob = ObjectBuilder::default();
     let open_file = ob.open_file(&filepath)?;
     let mut loaded_file = open_file.load()?;

     let bpffs_path = "/sys/fs/bpf/".to_owned();

     for mut map in loaded_file.maps_mut() {
         let mut desc_found = false;
         let name =
             map.name().to_str().ok_or_else(|| anyhow!("Failed to parse map name into UTF-8"))?;
         let name = String::from(name);
         for map_desc in file_desc.maps {
             if map_desc.name == name {
                 desc_found = true;
                 let pinpath_str = bpffs_path.clone() + "map_" + filename + "_" + &name;
                 let pinpath = Path::new(&pinpath_str);
                 debug!("Pinning: {}", pinpath.display());
                 map.pin(pinpath).map_err(|e| anyhow!("Failed to pin map {name}: {e}"))?;
                 fs::set_permissions(pinpath, Permissions::from_mode(map_desc.perms as _)).map_err(
                     |e| {
                         anyhow!(
                             "Failed to set permissions: {} on pinned map {}: {e}",
                             map_desc.perms,
                             pinpath.display()
                         )
                     },
                 )?;
                 chown(pinpath, Some(file_desc.owner), Some(file_desc.group)).map_err(|e| {
                     anyhow!(
                         "Failed to chown {} with owner: {} group: {} err: {e}",
                         pinpath.display(),
                         file_desc.owner,
                         file_desc.group
                     )
                 })?;
                 break;
             }
         }
         ensure!(desc_found, "Descriptor for {name} not found!");
     }

     for mut prog in loaded_file.progs_mut() {
         let mut desc_found = false;
         let name =
             prog.name().to_str().ok_or_else(|| anyhow!("Failed to parse prog name into UTF-8"))?;
         let name = String::from(name);
         for prog_desc in file_desc.progs {
             if prog_desc.name == name {
                 desc_found = true;
                 let pinpath_str = bpffs_path.clone() + "prog_" + filename + "_" + &name;
                 let pinpath = Path::new(&pinpath_str);
                 debug!("Pinning: {}", pinpath.display());
                 prog.pin(pinpath).map_err(|e| anyhow!("Failed to pin prog {name}: {e}"))?;
                 fs::set_permissions(pinpath, Permissions::from_mode(PERM_UGR as _)).map_err(
                     |e| {
                         anyhow!(
                             "Failed to set permissions on pinned prog {}: {e}",
                             pinpath.display()
                         )
                     },
                 )?;
                 chown(pinpath, Some(file_desc.owner), Some(file_desc.group)).map_err(|e| {
                     anyhow!(
                         "Failed to chown {} with owner: {} group: {} err: {e}",
                         pinpath.display(),
                         file_desc.owner,
                         file_desc.group
                     )
                 })?;
                 break;
             }
         }
         ensure!(desc_found, "Descriptor for {name} not found!");
     }
     Ok(())
 }

 #[cfg(enable_libbpf)]
 fn load_libbpf_progs() {
     info!("Loading libbpf programs");
     for file_desc in FILE_ARR {
         if let Err(e) = libbpf_worker(file_desc) {
             if file_desc.critical {
                 panic!("Error when loading {0}: {e}", file_desc.filename);
             } else {
                 error!("Error when loading {0}: {e}", file_desc.filename);
             }
         };
     }
 }

 #[cfg(not(enable_libbpf))]
 fn load_libbpf_progs() {
     // Empty stub for feature flag disabled case
     info!("Loading libbpf programs DISABLED");
 }

 fn main() {
     let kmsg_fd = env::var("ANDROID_FILE__dev_kmsg").unwrap().parse::<i32>().unwrap();
     // SAFETY: The init script opens this file for us
     let kmsg_file = unsafe { File::from_raw_fd(kmsg_fd) };

     if let Err(logger) = BpfKmsgLogger::init(kmsg_file) {
         error!("BpfLoader-rs: log::setlogger failed: {}", logger);
     }

     // Redirect panic messages to both logcat and serial port
     panic::set_hook(Box::new(|panic_info| {
         error!("{}", panic_info);
     }));

     load_libbpf_progs();
     info!("Loading legacy BPF progs");

     // SAFETY: Linking in the existing legacy bpfloader functionality.
     // Any of the four following bindgen functions can abort() or exit()
     // on failure and execNetBpfLoadDone() execve()'s.
     unsafe {
         bpf_android_bindgen::initLogging();
         bpf_android_bindgen::createBpfFsSubDirectories();
         bpf_android_bindgen::legacyBpfLoader();
         bpf_android_bindgen::execNetBpfLoadDone();
     }
 }
	/*
	* Copyright (C) 2024 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.
	*/

	//! BPF loader for system and vendor applications

	// Enable dead_code until feature flag is removed.
	#![cfg_attr(not(enable_libbpf), allow(dead_code))]

	use android_ids::{AID_ROOT, AID_SYSTEM};
	use android_logger::AndroidLogger;
	use anyhow::{anyhow, ensure};
	use libbpf_rs::{MapCore, ObjectBuilder};
	use libc::{mode_t, S_IRGRP, S_IRUSR, S_IWGRP, S_IWUSR};
	use log::{debug, error, info, Level, LevelFilter, Log, Metadata, Record, SetLoggerError};
	use std::{
	cmp::max,
	env, fs,
	fs::{File, Permissions},
	io::{LineWriter, Write},
	os::fd::FromRawFd,
	os::unix::fs::{chown, PermissionsExt},
	panic,
	path::Path,
	sync::{Arc, Mutex},
	};

	enum KernelLevel {
	// Commented out unused due to rust complaining...
	// EMERG = 0,
	// ALERT = 1,
	// CRIT = 2,
	ERR = 3,
	WARNING = 4,
	// NOTICE = 5,
	INFO = 6,
	DEBUG = 7,
	}

	fn level_to_kern_level(level: &Level) -> u8 {
	let result = match level {
	Level::Error => KernelLevel::ERR,
	Level::Warn => KernelLevel::WARNING,
	Level::Info => KernelLevel::INFO,
	Level::Debug => KernelLevel::DEBUG,
	Level::Trace => KernelLevel::DEBUG,
	};
	result as u8
	}

	/// A logger implementation to enable bpfloader to write to kmsg on error as
	/// bpfloader runs at early init prior to the availability of standard Android
	/// logging. If a crash were to occur, we can disrupt boot, and therefore we
	/// need the ability to access the logs on the serial port.
	pub struct BpfKmsgLogger {
	log_level: LevelFilter,
	tag: String,
	kmsg_writer: Arc<Mutex<Box<dyn Write + Send>>>,
	a_logger: AndroidLogger,
	}

	impl Log for BpfKmsgLogger {
	fn enabled(&self, metadata: &Metadata) -> bool {
	metadata.level() <= self.log_level \|\| self.a_logger.enabled(metadata)
	}

	fn log(&self, record: &Record) {
	if !self.enabled(record.metadata()) {
	return;
	}

	if record.metadata().level() <= self.log_level {
	let mut writer = self.kmsg_writer.lock().unwrap();
	write!(
	writer,
	"<{}>{}: {}",
	level_to_kern_level(&record.level()),
	self.tag,
	record.args()
	)
	.unwrap();
	let _ = writer.flush();
	}
	self.a_logger.log(record);
	}

	fn flush(&self) {}
	}

	impl BpfKmsgLogger {
	/// Initialize the logger
	pub fn init(kmsg_file: File) -> Result<(), SetLoggerError> {
	let alog_level = LevelFilter::Info;
	let kmsg_level = LevelFilter::Error;

	let log_config = android_logger::Config::default()
	.with_tag("BpfLoader-rs")
	.with_max_level(alog_level)
	.with_log_buffer(android_logger::LogId::Main)
	.format(\|buf, record\| writeln!(buf, "{}", record.args()));

	let writer = Box::new(LineWriter::new(kmsg_file)) as Box<dyn Write + Send>;
	log::set_max_level(max(alog_level, kmsg_level));
	log::set_boxed_logger(Box::new(BpfKmsgLogger {
	log_level: kmsg_level,
	tag: "BpfLoader-rs".to_string(),
	kmsg_writer: Arc::new(Mutex::new(writer)),
	a_logger: AndroidLogger::new(log_config),
	}))
	}
	}

	struct MapDesc {
	name: &'static str,
	perms: mode_t,
	}

	struct ProgDesc {
	name: &'static str,
	}

	struct BpfFileDesc {
	filename: &'static str,
	// Warning: setting this to 'true' will cause the system to boot loop if there are any issues
	// loading the bpf program.
	critical: bool,
	owner: u32,
	group: u32,
	maps: &'static [MapDesc],
	progs: &'static [ProgDesc],
	}

	const PERM_GRW: mode_t = S_IRUSR \| S_IWUSR \| S_IRGRP \| S_IWGRP;
	const PERM_GRO: mode_t = S_IRUSR \| S_IWUSR \| S_IRGRP;
	const PERM_GWO: mode_t = S_IRUSR \| S_IWUSR \| S_IWGRP;
	const PERM_UGR: mode_t = S_IRUSR \| S_IRGRP;

	const FILE_ARR: &[BpfFileDesc] = &[BpfFileDesc {
	filename: "timeInState.bpf",
	critical: false,
	owner: AID_ROOT,
	group: AID_SYSTEM,
	maps: &[
	MapDesc { name: "cpu_last_pid_map", perms: PERM_GWO },
	MapDesc { name: "cpu_last_update_map", perms: PERM_GWO },
	MapDesc { name: "cpu_policy_map", perms: PERM_GWO },
	MapDesc { name: "freq_to_idx_map", perms: PERM_GWO },
	MapDesc { name: "nr_active_map", perms: PERM_GWO },
	MapDesc { name: "pid_task_aggregation_map", perms: PERM_GWO },
	MapDesc { name: "pid_time_in_state_map", perms: PERM_GRO },
	MapDesc { name: "pid_tracked_hash_map", perms: PERM_GWO },
	MapDesc { name: "pid_tracked_map", perms: PERM_GWO },
	MapDesc { name: "policy_freq_idx_map", perms: PERM_GWO },
	MapDesc { name: "policy_nr_active_map", perms: PERM_GWO },
	MapDesc { name: "total_time_in_state_map", perms: PERM_GRW },
	MapDesc { name: "uid_concurrent_times_map", perms: PERM_GRW },
	MapDesc { name: "uid_last_update_map", perms: PERM_GRW },
	MapDesc { name: "uid_time_in_state_map", perms: PERM_GRW },
	],
	progs: &[
	ProgDesc { name: "tracepoint_power_cpu_frequency" },
	ProgDesc { name: "tracepoint_sched_sched_process_free" },
	ProgDesc { name: "tracepoint_sched_sched_switch" },
	],
	}];

	fn libbpf_worker(file_desc: &BpfFileDesc) -> Result<(), anyhow::Error> {
	info!("Loading {}", file_desc.filename);
	let filepath = Path::new("/etc/bpf/").join(file_desc.filename);
	ensure!(filepath.exists(), "File not found {}", filepath.display());
	let filename =
	filepath.file_stem().ok_or_else(\|\| anyhow!("Failed to parse stem from filename"))?;
	let filename = filename.to_str().ok_or_else(\|\| anyhow!("Failed to parse filename"))?;

	let mut ob = ObjectBuilder::default();
	let open_file = ob.open_file(&filepath)?;
	let mut loaded_file = open_file.load()?;

	let bpffs_path = "/sys/fs/bpf/".to_owned();

	for mut map in loaded_file.maps_mut() {
	let mut desc_found = false;
	let name =
	map.name().to_str().ok_or_else(\|\| anyhow!("Failed to parse map name into UTF-8"))?;
	let name = String::from(name);
	for map_desc in file_desc.maps {
	if map_desc.name == name {
	desc_found = true;
	let pinpath_str = bpffs_path.clone() + "map_" + filename + "_" + &name;
	let pinpath = Path::new(&pinpath_str);
	debug!("Pinning: {}", pinpath.display());
	map.pin(pinpath).map_err(\|e\| anyhow!("Failed to pin map {name}: {e}"))?;
	fs::set_permissions(pinpath, Permissions::from_mode(map_desc.perms as _)).map_err(
	\|e\| {
	anyhow!(
	"Failed to set permissions: {} on pinned map {}: {e}",
	map_desc.perms,
	pinpath.display()
	)
	},
	)?;
	chown(pinpath, Some(file_desc.owner), Some(file_desc.group)).map_err(\|e\| {
	anyhow!(
	"Failed to chown {} with owner: {} group: {} err: {e}",
	pinpath.display(),
	file_desc.owner,
	file_desc.group
	)
	})?;
	break;
	}
	}
	ensure!(desc_found, "Descriptor for {name} not found!");
	}

	for mut prog in loaded_file.progs_mut() {
	let mut desc_found = false;
	let name =
	prog.name().to_str().ok_or_else(\|\| anyhow!("Failed to parse prog name into UTF-8"))?;
	let name = String::from(name);
	for prog_desc in file_desc.progs {
	if prog_desc.name == name {
	desc_found = true;
	let pinpath_str = bpffs_path.clone() + "prog_" + filename + "_" + &name;
	let pinpath = Path::new(&pinpath_str);
	debug!("Pinning: {}", pinpath.display());
	prog.pin(pinpath).map_err(\|e\| anyhow!("Failed to pin prog {name}: {e}"))?;
	fs::set_permissions(pinpath, Permissions::from_mode(PERM_UGR as _)).map_err(
	\|e\| {
	anyhow!(
	"Failed to set permissions on pinned prog {}: {e}",
	pinpath.display()
	)
	},
	)?;
	chown(pinpath, Some(file_desc.owner), Some(file_desc.group)).map_err(\|e\| {
	anyhow!(
	"Failed to chown {} with owner: {} group: {} err: {e}",
	pinpath.display(),
	file_desc.owner,
	file_desc.group
	)
	})?;
	break;
	}
	}
	ensure!(desc_found, "Descriptor for {name} not found!");
	}
	Ok(())
	}

	#[cfg(enable_libbpf)]
	fn load_libbpf_progs() {
	info!("Loading libbpf programs");
	for file_desc in FILE_ARR {
	if let Err(e) = libbpf_worker(file_desc) {
	if file_desc.critical {
	panic!("Error when loading {0}: {e}", file_desc.filename);
	} else {
	error!("Error when loading {0}: {e}", file_desc.filename);
	}
	};
	}
	}

	#[cfg(not(enable_libbpf))]
	fn load_libbpf_progs() {
	// Empty stub for feature flag disabled case
	info!("Loading libbpf programs DISABLED");
	}

	fn main() {
	let kmsg_fd = env::var("ANDROID_FILE__dev_kmsg").unwrap().parse::<i32>().unwrap();
	// SAFETY: The init script opens this file for us
	let kmsg_file = unsafe { File::from_raw_fd(kmsg_fd) };

	if let Err(logger) = BpfKmsgLogger::init(kmsg_file) {
	error!("BpfLoader-rs: log::setlogger failed: {}", logger);
	}

	// Redirect panic messages to both logcat and serial port
	panic::set_hook(Box::new(\|panic_info\| {
	error!("{}", panic_info);
	}));

	load_libbpf_progs();
	info!("Loading legacy BPF progs");

	// SAFETY: Linking in the existing legacy bpfloader functionality.
	// Any of the four following bindgen functions can abort() or exit()
	// on failure and execNetBpfLoadDone() execve()'s.
	unsafe {
	bpf_android_bindgen::initLogging();
	bpf_android_bindgen::createBpfFsSubDirectories();
	bpf_android_bindgen::legacyBpfLoader();
	bpf_android_bindgen::execNetBpfLoadDone();
	}
	}