Move the Rust system property bindings into librustutils.
Bug: 182498247
Test: Build
Change-Id: I688a1c7654d94b349b6903d9e7735656d31e7629
diff --git a/libc/NOTICE b/libc/NOTICE
index 8260112..ff16da7 100644
--- a/libc/NOTICE
+++ b/libc/NOTICE
@@ -883,22 +883,6 @@
-------------------------------------------------------------------
Copyright (C) 2021 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.
-
--------------------------------------------------------------------
-
-Copyright (C) 2021 The Android Open Source Project
All rights reserved.
Redistribution and use in source and binary forms, with or without
diff --git a/libc/rust/Android.bp b/libc/rust/Android.bp
deleted file mode 100644
index 44cf848..0000000
--- a/libc/rust/Android.bp
+++ /dev/null
@@ -1,30 +0,0 @@
-rust_bindgen {
- name: "libsystem_properties_bindgen",
- wrapper_src: "system_properties_bindgen.hpp",
- crate_name: "system_properties_bindgen",
- source_stem: "bindings",
-
- bindgen_flags: [
- "--size_t-is-usize",
- "--allowlist-function=__system_property_find",
- "--allowlist-function=__system_property_read_callback",
- "--allowlist-function=__system_property_set",
- "--allowlist-function=__system_property_wait",
- ],
-}
-
-rust_library {
- name: "libsystem_properties-rust",
- crate_name: "system_properties",
- srcs: [
- "system_properties.rs",
- ],
- rustlibs: [
- "libanyhow",
- "libsystem_properties_bindgen",
- "libthiserror",
- ],
- shared_libs: [
- "libbase",
- ],
-}
diff --git a/libc/rust/system_properties.rs b/libc/rust/system_properties.rs
deleted file mode 100644
index 189e8ee..0000000
--- a/libc/rust/system_properties.rs
+++ /dev/null
@@ -1,227 +0,0 @@
-/*
- * Copyright (C) 2021 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.
- */
-
-//! This crate provides the PropertyWatcher type, which watches for changes
-//! in Android system properties.
-
-use anyhow::{anyhow, Context, Result as AnyhowResult};
-use system_properties_bindgen::prop_info as PropInfo;
-use std::os::raw::c_char;
-use std::ptr::null;
-use std::{
- ffi::{c_void, CStr, CString},
- str::Utf8Error,
-};
-use thiserror::Error;
-
-/// Errors this crate can generate
-#[derive(Error, Debug)]
-pub enum PropertyWatcherError {
- /// We can't watch for a property whose name contains a NUL character.
- #[error("Cannot convert name to C string")]
- BadNameError(#[from] std::ffi::NulError),
- /// We can only watch for properties that exist when the watcher is created.
- #[error("System property is absent")]
- SystemPropertyAbsent,
- /// __system_property_wait timed out despite being given no timeout.
- #[error("Wait failed")]
- WaitFailed,
- /// read callback was not called
- #[error("__system_property_read_callback did not call callback")]
- ReadCallbackNotCalled,
- /// read callback gave us a NULL pointer
- #[error("__system_property_read_callback gave us a NULL pointer instead of a string")]
- MissingCString,
- /// read callback gave us a bad C string
- #[error("__system_property_read_callback gave us a non-UTF8 C string")]
- BadCString(#[from] Utf8Error),
- /// read callback returned an error
- #[error("Callback failed")]
- CallbackError(#[from] anyhow::Error),
- /// Failure in setting the system property
- #[error("__system_property_set failed.")]
- SetPropertyFailed,
-}
-
-/// Result type specific for this crate.
-pub type Result<T> = std::result::Result<T, PropertyWatcherError>;
-
-/// PropertyWatcher takes the name of an Android system property such
-/// as `keystore.boot_level`; it can report the current value of this
-/// property, or wait for it to change.
-pub struct PropertyWatcher {
- prop_name: CString,
- prop_info: *const PropInfo,
- serial: system_properties_bindgen::__uint32_t,
-}
-
-impl PropertyWatcher {
- /// Create a PropertyWatcher for the named system property.
- pub fn new(name: &str) -> Result<Self> {
- Ok(Self { prop_name: CString::new(name)?, prop_info: null(), serial: 0 })
- }
-
- // Lazy-initializing accessor for self.prop_info.
- fn get_prop_info(&mut self) -> Option<*const PropInfo> {
- if self.prop_info.is_null() {
- // Unsafe required for FFI call. Input and output are both const.
- // The returned pointer is valid for the lifetime of the program.
- self.prop_info = unsafe {
- system_properties_bindgen::__system_property_find(self.prop_name.as_ptr())
- };
- }
- if self.prop_info.is_null() {
- None
- } else {
- Some(self.prop_info)
- }
- }
-
- fn read_raw(prop_info: *const PropInfo, mut f: impl FnOnce(Option<&CStr>, Option<&CStr>)) {
- // Unsafe function converts values passed to us by
- // __system_property_read_callback to Rust form
- // and pass them to inner callback.
- unsafe extern "C" fn callback(
- res_p: *mut c_void,
- name: *const c_char,
- value: *const c_char,
- _: system_properties_bindgen::__uint32_t,
- ) {
- let name = if name.is_null() { None } else { Some(CStr::from_ptr(name)) };
- let value = if value.is_null() { None } else { Some(CStr::from_ptr(value)) };
- let f = &mut *res_p.cast::<&mut dyn FnMut(Option<&CStr>, Option<&CStr>)>();
- f(name, value);
- }
-
- let mut f: &mut dyn FnOnce(Option<&CStr>, Option<&CStr>) = &mut f;
-
- // Unsafe block for FFI call. We convert the FnOnce
- // to a void pointer, and unwrap it in our callback.
- unsafe {
- system_properties_bindgen::__system_property_read_callback(
- prop_info,
- Some(callback),
- &mut f as *mut _ as *mut c_void,
- )
- }
- }
-
- /// Call the passed function, passing it the name and current value
- /// of this system property. See documentation for
- /// `__system_property_read_callback` for details.
- /// Returns an error if the property is empty or doesn't exist.
- pub fn read<T, F>(&mut self, f: F) -> Result<T>
- where
- F: FnOnce(&str, &str) -> anyhow::Result<T>,
- {
- let prop_info = self.get_prop_info().ok_or(PropertyWatcherError::SystemPropertyAbsent)?;
- let mut result = Err(PropertyWatcherError::ReadCallbackNotCalled);
- Self::read_raw(prop_info, |name, value| {
- // use a wrapping closure as an erzatz try block.
- result = (|| {
- let name = name.ok_or(PropertyWatcherError::MissingCString)?.to_str()?;
- let value = value.ok_or(PropertyWatcherError::MissingCString)?.to_str()?;
- f(name, value).map_err(PropertyWatcherError::CallbackError)
- })()
- });
- result
- }
-
- // Waits for the property that self is watching to be created. Returns immediately if the
- // property already exists.
- fn wait_for_property_creation(&mut self) -> Result<()> {
- let mut global_serial = 0;
- loop {
- match self.get_prop_info() {
- Some(_) => return Ok(()),
- None => {
- // Unsafe call for FFI. The function modifies only global_serial, and has
- // no side-effects.
- if !unsafe {
- // Wait for a global serial number change, then try again. On success,
- // the function will update global_serial with the last version seen.
- system_properties_bindgen::__system_property_wait(
- null(),
- global_serial,
- &mut global_serial,
- null(),
- )
- } {
- return Err(PropertyWatcherError::WaitFailed);
- }
- }
- }
- }
- }
-
- /// Wait for the system property to change. This
- /// records the serial number of the last change, so
- /// race conditions are avoided.
- pub fn wait(&mut self) -> Result<()> {
- // If the property is null, then wait for it to be created. Subsequent waits will
- // skip this step and wait for our specific property to change.
- if self.prop_info.is_null() {
- return self.wait_for_property_creation();
- }
-
- let mut new_serial = self.serial;
- // Unsafe block to call __system_property_wait.
- // All arguments are private to PropertyWatcher so we
- // can be confident they are valid.
- if !unsafe {
- system_properties_bindgen::__system_property_wait(
- self.prop_info,
- self.serial,
- &mut new_serial,
- null(),
- )
- } {
- return Err(PropertyWatcherError::WaitFailed);
- }
- self.serial = new_serial;
- Ok(())
- }
-}
-
-/// Reads a system property.
-pub fn read(name: &str) -> AnyhowResult<String> {
- PropertyWatcher::new(name)
- .context("Failed to create a PropertyWatcher.")?
- .read(|_name, value| Ok(value.to_owned()))
- .with_context(|| format!("Failed to read the system property {}.", name))
-}
-
-/// Writes a system property.
-pub fn write(name: &str, value: &str) -> AnyhowResult<()> {
- if
- // Unsafe required for FFI call. Input and output are both const and valid strings.
- unsafe {
- // If successful, __system_property_set returns 0, otherwise, returns -1.
- system_properties_bindgen::__system_property_set(
- CString::new(name)
- .context("Failed to construct CString from name.")?
- .as_ptr(),
- CString::new(value)
- .context("Failed to construct CString from value.")?
- .as_ptr(),
- )
- } == 0
- {
- Ok(())
- } else {
- Err(anyhow!(PropertyWatcherError::SetPropertyFailed))
- }
-}
diff --git a/libc/rust/system_properties_bindgen.hpp b/libc/rust/system_properties_bindgen.hpp
deleted file mode 100644
index 307cd6c..0000000
--- a/libc/rust/system_properties_bindgen.hpp
+++ /dev/null
@@ -1,19 +0,0 @@
-/*
- * Copyright (C) 2021 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.
- */
-
-#pragma once
-
-#include "sys/system_properties.h"