use std::{
env, fs,
fs::File,
io::{self, Write},
path::{Path, PathBuf},
process::Command,
};
use anyhow::{bail, Context, Result};
use fs2::FileExt;
pub const SHOES_BIN: &str = "/usr/local/bin/shoes";
pub const CONFIG_DIR: &str = "/etc/shoes";
pub const CONFIG_FILE: &str = "/etc/shoes/config.yaml";
pub const STATE_FILE: &str = "/etc/shoes/ping-rust-state.json";
pub const LOCK_FILE: &str = "/run/lock/ping-rust.lock";
pub const SERVICE_FILE: &str = "/etc/systemd/system/shoes.service";
pub fn require_linux() -> Result<()> {
if cfg!(target_os = "linux") {
Ok(())
} else {
bail!("该操作仅支持 Linux；当前系统为 {}", std::env::consts::OS)
}
}
pub fn require_linux_root() -> Result<()> {
require_linux()?;
let output = Command::new("id")
.arg("-u")
.output()
.context("无法检查当前用户权限")?;
if !output.status.success() || String::from_utf8_lossy(&output.stdout).trim() != "0" {
bail!("该操作需要 root 权限，请使用 sudo ping-rust ...")
}
Ok(())
}
pub fn command_exists(name: &str) -> bool {
command_path(name).is_some()
}
pub fn command_path(name: &str) -> Option<PathBuf> {
let requested = Path::new(name);
if requested.components().count() > 1 {
return is_executable(requested).then(|| requested.to_path_buf());
}
env::var_os("PATH")
.and_then(|path| {
env::split_paths(&path).find_map(|directory| {
command_candidates(&directory, name)
.into_iter()
.find(|candidate| is_executable(candidate))
})
})
.or_else(|| {
std::env::current_exe().ok().and_then(|executable| {
executable.parent().and_then(|parent| {
command_candidates(parent, name)
.into_iter()
.find(|candidate| is_executable(candidate))
})
})
})
}
fn command_candidates(directory: &Path, name: &str) -> Vec<PathBuf> {
let base = directory.join(name);
#[cfg(windows)]
{
if Path::new(name).extension().is_some() {
return vec![base];
}
let extensions = env::var_os("PATHEXT")
.map(|value| {
value
.to_string_lossy()
.split(';')
.filter(|extension| !extension.is_empty())
.map(|extension| base.with_extension(extension.trim_start_matches('.')))
.collect::<Vec<_>>()
})
.unwrap_or_else(|| vec![base.with_extension("exe")]);
extensions
}
#[cfg(not(windows))]
vec![base]
}
#[cfg(unix)]
fn is_executable(path: &Path) -> bool {
use std::os::unix::fs::PermissionsExt;
path.metadata()
.map(|metadata| metadata.is_file() && metadata.permissions().mode() & 0o111 != 0)
.unwrap_or(false)
}
#[cfg(not(unix))]
fn is_executable(path: &Path) -> bool {
path.is_file()
}
pub struct ExclusiveLock(File);
pub fn exclusive_lock(path: &Path) -> Result<ExclusiveLock> {
let parent = path.parent().context("锁文件路径没有父目录")?;
fs::create_dir_all(parent).with_context(|| format!("创建锁目录 {} 失败", parent.display()))?;
let file = File::options()
.read(true)
.write(true)
.create(true)
.truncate(false)
.open(path)
.with_context(|| format!("打开锁文件 {} 失败", path.display()))?;
set_mode(path, 0o600)?;
file.lock_exclusive()
.with_context(|| format!("锁定 {} 失败", path.display()))?;
Ok(ExclusiveLock(file))
}
impl Drop for ExclusiveLock {
fn drop(&mut self) {
let _ = self.0.unlock();
}
}
pub fn atomic_write(destination: &Path, contents: &[u8], mode: u32) -> Result<()> {
let parent = destination.parent().context("目标路径没有父目录")?;
let parent = if parent.as_os_str().is_empty() {
Path::new(".")
} else {
parent
};
fs::create_dir_all(parent).with_context(|| format!("创建目录 {} 失败", parent.display()))?;
let mut temp = tempfile::NamedTempFile::new_in(parent)
.with_context(|| format!("无法在 {} 创建临时文件", parent.display()))?;
temp.write_all(contents).context("写入临时文件失败")?;
temp.as_file().sync_all().context("同步临时文件失败")?;
set_mode(temp.path(), mode)?;
persist_replace(temp, destination)
}
pub fn atomic_copy(source: &Path, destination: &Path, mode: u32) -> Result<()> {
let bytes = fs::read(source).with_context(|| format!("读取 {} 失败", source.display()))?;
atomic_write(destination, &bytes, mode)
}
fn persist_replace(temp: tempfile::NamedTempFile, destination: &Path) -> Result<()> {
#[cfg(target_os = "windows")]
if destination.exists() {
fs::remove_file(destination)
.with_context(|| format!("替换 {} 失败", destination.display()))?;
}
temp.persist(destination)
.map_err(|error| error.error)
.with_context(|| format!("原子替换 {} 失败", destination.display()))?;
Ok(())
}
#[cfg(unix)]
fn set_mode(path: &Path, mode: u32) -> io::Result<()> {
use std::os::unix::fs::PermissionsExt;
fs::set_permissions(path, fs::Permissions::from_mode(mode))
}
#[cfg(not(unix))]
fn set_mode(_path: &Path, _mode: u32) -> io::Result<()> {
Ok(())
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn atomic_write_replaces_content() {
let dir = tempfile::tempdir().unwrap();
let file = dir.path().join("config.yaml");
atomic_write(&file, b"first", 0o600).unwrap();
atomic_write(&file, b"second", 0o600).unwrap();
assert_eq!(fs::read(file).unwrap(), b"second");
}
#[test]
fn command_exists_does_not_require_which() {
assert!(command_exists(
std::env::current_exe().unwrap().to_str().unwrap()
));
assert!(!command_exists("ping-rust-command-that-does-not-exist"));
}
#[test]
fn exclusive_lock_can_be_reacquired_after_drop() {
let dir = tempfile::tempdir().unwrap();
let path = dir.path().join("lock");
drop(exclusive_lock(&path).unwrap());
drop(exclusive_lock(&path).unwrap());
}
}