forked from brl/citadel-tools
67 lines
1.7 KiB
Rust
67 lines
1.7 KiB
Rust
use std::fs;
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use std::path::{Path,PathBuf};
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use std::os::unix;
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use crate::Result;
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pub fn read(path: impl AsRef<Path>) -> Option<PathBuf> {
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let path = path.as_ref();
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if fs::symlink_metadata(path).is_err() {
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return None;
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}
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match fs::read_link(path) {
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Ok(target) => Some(target),
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Err(err) => {
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warn!("error reading {} symlink: {}", path.display(), err);
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None
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}
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}
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}
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// write symlink atomically and if tmp_in_parent is set, create the tmp link in parent directory
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// This is used so that the directory /run/citadel/realms/current can be monitored for changes
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// without inotify firing when the tmp link is created.
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pub fn write(target: impl AsRef<Path>, link: impl AsRef<Path>, tmp_in_parent: bool) -> Result<()> {
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let link = link.as_ref();
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let target = target.as_ref();
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let tmp = write_tmp_path(link, tmp_in_parent);
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if let Some(parent) = link.parent() {
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if !parent.exists() {
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fs::create_dir_all(parent)?;
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}
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}
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if tmp.exists() {
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fs::remove_file(&tmp)?;
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}
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unix::fs::symlink(target, &tmp)?;
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fs::rename(&tmp, link)?;
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Ok(())
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}
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fn write_tmp_path(link: &Path, tmp_in_parent: bool) -> PathBuf {
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let n = if tmp_in_parent { 2 } else { 1 };
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let tmp_dir = link.ancestors().nth(n)
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.expect("No parent directory in write_symlink");
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let mut tmp_fname = link.file_name()
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.expect("No filename in write_symlink()")
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.to_os_string();
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tmp_fname.push(".tmp");
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tmp_dir.join(tmp_fname)
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}
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pub fn remove(path: impl AsRef<Path>) -> Result<()> {
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let path = path.as_ref();
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if fs::symlink_metadata(path).is_ok() {
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fs::remove_file(path)?;
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}
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Ok(())
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}
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