Files
depot/src/staging/transaction.rs
T

718 lines
26 KiB
Rust

use super::*;
#[derive(Debug)]
pub struct FsTransaction {
rootfs: PathBuf,
pub(super) tx_dir: PathBuf,
backed_up: Vec<String>,
created: Vec<String>,
relocated: Vec<String>,
removed: Vec<String>,
}
pub(super) fn is_directory_empty(path: &Path) -> Result<bool> {
let mut entries = fs::read_dir(path)
.with_context(|| format!("Failed to read directory {}", path.display()))?;
Ok(entries.next().transpose()?.is_none())
}
pub(super) fn backup_existing_path(src: &Path, backup_path: &Path, rel: &str) -> Result<()> {
let metadata = src
.symlink_metadata()
.with_context(|| format!("Failed to inspect existing path {}", rel))?;
if let Some(parent) = backup_path.parent() {
fs::create_dir_all(parent)
.with_context(|| format!("Failed to create backup dir {}", parent.display()))?;
}
if metadata.file_type().is_symlink() {
let target = fs::read_link(src)
.with_context(|| format!("Failed to read existing symlink target {}", rel))?;
std::os::unix::fs::symlink(&target, backup_path)
.with_context(|| format!("Failed to backup symlink {}", rel))?;
} else if metadata.file_type().is_dir() {
fs::create_dir_all(backup_path)
.with_context(|| format!("Failed to backup directory {}", rel))?;
apply_unix_mode(backup_path, &metadata)?;
} else {
fs::copy(src, backup_path).with_context(|| format!("Failed to backup file {}", rel))?;
}
Ok(())
}
pub(super) fn move_directory_contents(src_dir: &Path, dst_dir: &Path) -> Result<()> {
fs::create_dir_all(dst_dir)
.with_context(|| format!("Failed to create directory {}", dst_dir.display()))?;
for entry in
fs::read_dir(src_dir).with_context(|| format!("Failed to read {}", src_dir.display()))?
{
let entry = entry?;
move_tree_preserving_layout(&entry.path(), &dst_dir.join(entry.file_name()))?;
}
fs::remove_dir(src_dir).with_context(|| format!("Failed to remove {}", src_dir.display()))?;
Ok(())
}
pub(super) fn copy_tree_preserving_layout_no_overwrite(
src_root: &Path,
dst_root: &Path,
logical_root: &str,
created: &mut Vec<String>,
) -> Result<()> {
for entry in WalkDir::new(src_root).follow_links(false) {
let entry = entry
.with_context(|| format!("Failed to walk relocation tree {}", src_root.display()))?;
let src_path = entry.path();
let rel = src_path
.strip_prefix(src_root)
.with_context(|| format!("Failed to strip relocation root {}", src_root.display()))?;
if rel.as_os_str().is_empty() {
continue;
}
let dst_path = dst_root.join(rel);
let metadata = src_path
.symlink_metadata()
.with_context(|| format!("Failed to inspect {}", src_path.display()))?;
let file_type = metadata.file_type();
if file_type.is_dir() {
match dst_path.symlink_metadata() {
Ok(dst_meta) => {
if !dst_meta.file_type().is_dir() {
anyhow::bail!(
"Failed to replay relocated directory into {}: destination exists and is not a directory",
dst_path.display()
);
}
}
Err(err) if err.kind() == io::ErrorKind::NotFound => {
fs::create_dir_all(&dst_path).with_context(|| {
format!("Failed to create directory {}", dst_path.display())
})?;
apply_unix_mode(&dst_path, &metadata)?;
}
Err(err) => {
return Err(err)
.with_context(|| format!("Failed to inspect {}", dst_path.display()));
}
}
continue;
}
if let Some(parent) = dst_path.parent() {
fs::create_dir_all(parent)
.with_context(|| format!("Failed to create directory {}", parent.display()))?;
}
if let Ok(dst_metadata) = dst_path.symlink_metadata() {
if duplicate_staged_path_is_equivalent(src_path, &metadata, &dst_path, &dst_metadata)? {
continue;
}
anyhow::bail!(
"Failed to replay relocated path into {}: destination already exists",
dst_path.display()
);
}
if file_type.is_symlink() {
let target = fs::read_link(src_path)
.with_context(|| format!("Failed to read symlink {}", src_path.display()))?;
std::os::unix::fs::symlink(&target, &dst_path).with_context(|| {
format!(
"Failed to create relocated symlink {} -> {}",
dst_path.display(),
target.display()
)
})?;
} else {
fs::copy(src_path, &dst_path).with_context(|| {
format!(
"Failed to copy relocated path {} to {}",
src_path.display(),
dst_path.display()
)
})?;
apply_unix_mode(&dst_path, &metadata)?;
}
let logical = Path::new(logical_root).join(rel);
let logical = logical
.to_str()
.context("Relocated install paths must be valid UTF-8")?
.to_string();
created.push(logical);
}
Ok(())
}
pub(super) fn symlink_target_path_inside_rootfs(
rootfs: &Path,
link_rel: &str,
target: &Path,
) -> Result<Option<PathBuf>> {
let mut normalized = PathBuf::new();
if target.is_absolute() {
for component in target.components() {
match component {
Component::RootDir => {}
Component::CurDir => {}
Component::Normal(segment) => normalized.push(segment),
Component::ParentDir | Component::Prefix(_) => return Ok(None),
}
}
} else {
if let Some(parent) = Path::new(link_rel).parent() {
normalized.push(parent);
}
for component in target.components() {
match component {
Component::CurDir => {}
Component::Normal(segment) => normalized.push(segment),
Component::ParentDir => {
if !normalized.pop() {
return Ok(None);
}
}
Component::RootDir | Component::Prefix(_) => return Ok(None),
}
}
}
if normalized.as_os_str().is_empty() {
return Ok(None);
}
Ok(Some(rootfs.join(normalized)))
}
pub(super) fn can_relocate_directory_for_symlink_swap(
rootfs: &Path,
link_rel: &str,
symlink_path: &Path,
) -> Result<bool> {
let target = fs::read_link(symlink_path)
.with_context(|| format!("Failed to read symlink {}", symlink_path.display()))?;
let Some(target_path) = symlink_target_path_inside_rootfs(rootfs, link_rel, &target)? else {
return Ok(false);
};
match target_path.symlink_metadata() {
Ok(metadata) => Ok(metadata.file_type().is_dir()),
Err(err) if err.kind() == io::ErrorKind::NotFound => Ok(false),
Err(err) => Err(err)
.with_context(|| format!("Failed to inspect symlink target {}", target_path.display())),
}
}
pub(super) fn remove_path_in_place(path: &Path, rel: &str) -> Result<()> {
let metadata = path
.symlink_metadata()
.with_context(|| format!("Failed to inspect existing path {}", rel))?;
if metadata.file_type().is_dir() {
fs::remove_dir(path)
.with_context(|| format!("Failed to remove obsolete directory {}", rel))?;
} else {
fs::remove_file(path)
.with_context(|| format!("Failed to remove obsolete file/symlink {}", rel))?;
}
Ok(())
}
pub(super) fn backup_and_remove_obsolete_path(
tx: &mut FsTransaction,
rootfs: &Path,
rel: &str,
require_empty_dir: bool,
) -> Result<bool> {
let dest_path = rootfs.join(rel);
let metadata = match dest_path.symlink_metadata() {
Ok(metadata) => metadata,
Err(err) if err.kind() == io::ErrorKind::NotFound => return Ok(false),
Err(err) => {
return Err(err).with_context(|| {
format!("Failed to inspect obsolete path before removal: {}", rel)
});
}
};
if metadata.file_type().is_dir() {
let empty = is_directory_empty(&dest_path)?;
if !empty {
if require_empty_dir {
anyhow::bail!(
"Refusing to replace existing non-empty directory with packaged file/symlink: {}",
rel
);
}
return Ok(false);
}
}
let backup_path = tx.removed_backup_path(rel);
backup_existing_path(&dest_path, &backup_path, rel)?;
remove_path_in_place(&dest_path, rel)?;
tx.removed.push(rel.to_string());
Ok(true)
}
pub(super) fn remove_obsolete_children_for_dir(
tx: &mut FsTransaction,
rootfs: &Path,
dir_rel: &str,
remove_paths: &[String],
) -> Result<()> {
let prefix = format!("{dir_rel}/");
let mut nested_paths: Vec<&str> = remove_paths
.iter()
.filter_map(|path| path.strip_prefix(&prefix).map(|_| path.as_str()))
.collect();
nested_paths.sort_by_key(|path| std::cmp::Reverse(path.matches('/').count()));
for rel in nested_paths {
let _ = backup_and_remove_obsolete_path(tx, rootfs, rel, false)?;
}
Ok(())
}
impl FsTransaction {
fn backup_path(&self, rel: &str) -> PathBuf {
self.tx_dir.join("backup").join(rel)
}
fn removed_backup_path(&self, rel: &str) -> PathBuf {
self.tx_dir.join("removed").join(rel)
}
fn relocated_path(&self, rel: &str) -> PathBuf {
self.tx_dir.join("relocated").join(rel)
}
fn relocate_directory_for_symlink_swap(&mut self, rel: &str) -> Result<()> {
let src = self.rootfs.join(rel);
let relocated = self.relocated_path(rel);
move_directory_contents(&src, &relocated)?;
self.relocated.push(rel.to_string());
Ok(())
}
fn replay_relocated_dir_if_present(&mut self, rel: &str) -> Result<()> {
let relocated = self.relocated_path(rel);
match relocated.symlink_metadata() {
Ok(meta) if meta.file_type().is_dir() => {}
Ok(_) => {
anyhow::bail!(
"Relocation staging path is not a directory: {}",
relocated.display()
);
}
Err(err) if err.kind() == io::ErrorKind::NotFound => return Ok(()),
Err(err) => {
return Err(err)
.with_context(|| format!("Failed to inspect {}", relocated.display()));
}
}
copy_tree_preserving_layout_no_overwrite(
&relocated,
&self.rootfs.join(rel),
rel,
&mut self.created,
)
}
fn restore_relocated_dir(&self, rel: &str) -> Result<()> {
let relocated = self.relocated_path(rel);
match relocated.symlink_metadata() {
Ok(meta) if meta.file_type().is_dir() => {}
Ok(_) => {
anyhow::bail!(
"Relocation staging path is not a directory: {}",
relocated.display()
);
}
Err(err) if err.kind() == io::ErrorKind::NotFound => return Ok(()),
Err(err) => {
return Err(err)
.with_context(|| format!("Failed to inspect {}", relocated.display()));
}
}
let dst = self.rootfs.join(rel);
match dst.symlink_metadata() {
Ok(meta) if meta.file_type().is_dir() => {}
Ok(_) => {
anyhow::bail!(
"Failed to restore relocated directory contents into {}: destination is not a directory",
dst.display()
);
}
Err(err) if err.kind() == io::ErrorKind::NotFound => {
fs::create_dir_all(&dst)
.with_context(|| format!("Failed to create directory {}", dst.display()))?;
}
Err(err) => {
return Err(err).with_context(|| format!("Failed to inspect {}", dst.display()));
}
}
move_directory_contents(&relocated, &dst)?;
cleanup_empty_parent_dirs(&self.tx_dir, &relocated)?;
Ok(())
}
fn restore_backup_entry(&self, src: &Path, dst: &Path) -> Result<()> {
let metadata = src
.symlink_metadata()
.with_context(|| format!("Failed to inspect backup entry {}", src.display()))?;
if let Some(parent) = dst.parent() {
fs::create_dir_all(parent)
.with_context(|| format!("Failed to create restore dir {}", parent.display()))?;
}
if metadata.file_type().is_dir() {
match dst.symlink_metadata() {
Ok(dst_meta) if dst_meta.file_type().is_dir() => {}
Ok(dst_meta) if dst_meta.file_type().is_symlink() => {
fs::remove_file(dst)
.with_context(|| format!("Failed to remove {}", dst.display()))?;
}
Ok(_) => {
fs::remove_file(dst)
.with_context(|| format!("Failed to remove {}", dst.display()))?;
}
Err(err) if err.kind() == io::ErrorKind::NotFound => {}
Err(err) => {
return Err(err)
.with_context(|| format!("Failed to inspect {}", dst.display()));
}
}
fs::create_dir_all(dst)
.with_context(|| format!("Failed to restore directory {}", dst.display()))?;
apply_unix_mode(dst, &metadata)?;
return Ok(());
}
let _ = fs::remove_file(dst);
match fs::rename(src, dst) {
Ok(()) => Ok(()),
Err(_) if metadata.file_type().is_symlink() => {
let target = fs::read_link(src)
.with_context(|| format!("Failed to read backup symlink {}", src.display()))?;
std::os::unix::fs::symlink(&target, dst)
.with_context(|| format!("Failed to restore symlink {}", dst.display()))
}
Err(_) => {
fs::copy(src, dst).with_context(|| {
format!(
"Failed to restore file {} from {}",
dst.display(),
src.display()
)
})?;
Ok(())
}
}
}
/// Roll back file operations performed by `install_atomic`.
pub fn rollback(&self) -> Result<()> {
// Remove files that were newly created
for rel in &self.created {
let dst = self.rootfs.join(rel);
let _ = fs::remove_file(dst);
}
// Restore overwritten paths first so relocated and removed children have their parent layout.
for rel in &self.backed_up {
let src = self.backup_path(rel);
let dst = self.rootfs.join(rel);
if src.symlink_metadata().is_ok() {
self.restore_backup_entry(&src, &dst)?;
}
}
for rel in &self.relocated {
self.restore_relocated_dir(rel)?;
}
// Restore removed files/directories.
for rel in &self.removed {
let src = self.removed_backup_path(rel);
let dst = self.rootfs.join(rel);
if src.symlink_metadata().is_ok() {
self.restore_backup_entry(&src, &dst)?;
}
}
Ok(())
}
/// Commit the transaction (delete backup directory).
pub fn commit(self) -> Result<()> {
let tx_base_dir = self.tx_dir.parent().map(Path::to_path_buf);
if self.tx_dir.exists() {
fs::remove_dir_all(&self.tx_dir)?;
}
if let Some(tx_base_dir) = tx_base_dir {
match fs::remove_dir(&tx_base_dir) {
Ok(()) => {}
Err(err)
if matches!(
err.kind(),
io::ErrorKind::DirectoryNotEmpty | io::ErrorKind::NotFound
) => {}
Err(err) => {
return Err(err).with_context(|| {
format!("Failed to remove tx dir {}", tx_base_dir.display())
});
}
}
}
Ok(())
}
}
/// Install staged files using a rollback-capable transaction.
///
/// This is used for both first-time installs and updates. For updates, pass a
/// list of relative paths to remove (old manifest minus new manifest).
pub fn install_atomic(
destdir: &Path,
rootfs: &Path,
tx_base_dir: &Path,
remove_paths: &[String],
keep_paths: &[String],
) -> Result<FsTransaction> {
let tx_base_dir = if rootfs != Path::new("/") && tx_base_dir.starts_with(rootfs) {
rootfs.join(".depot-tx")
} else {
tx_base_dir.to_path_buf()
};
let keep_rules: Vec<KeepMatcher> = keep_paths
.iter()
.map(|p| KeepMatcher::from_spec(p))
.collect::<Result<Vec<_>>>()?;
let keep_set: HashSet<String> = keep_rules
.iter()
.filter_map(|m| match m {
KeepMatcher::Exact(p) => Some(p.clone()),
KeepMatcher::Pattern(_) => None,
})
.collect();
let remove_set: HashSet<&str> = remove_paths.iter().map(String::as_str).collect();
fs::create_dir_all(&tx_base_dir)
.with_context(|| format!("Failed to create tx dir: {}", tx_base_dir.display()))?;
let ts = SystemTime::now()
.duration_since(UNIX_EPOCH)
.unwrap_or_default()
.as_millis();
let pid = std::process::id();
let tx_dir = tx_base_dir.join(format!("tx-{}-{}", ts, pid));
let backup_dir = tx_dir.join("backup");
let removed_dir = tx_dir.join("removed");
fs::create_dir_all(&backup_dir)?;
fs::create_dir_all(&removed_dir)?;
let mut tx = FsTransaction {
rootfs: rootfs.to_path_buf(),
tx_dir,
backed_up: Vec::new(),
created: Vec::new(),
relocated: Vec::new(),
removed: Vec::new(),
};
let mut staged_paths = HashSet::new();
let mut installed_hardlinks: HashMap<HardlinkKey, String> = HashMap::new();
let result: Result<()> = (|| {
// First, create all directories from destdir (for packages with only directories)
for entry in WalkDir::new(destdir).into_iter().filter_map(|e| e.ok()) {
let src_path = entry.path();
let file_type = entry.file_type();
if !file_type.is_dir() || src_path == destdir {
continue;
}
let rel_path = src_path
.strip_prefix(destdir)
.context("Failed to strip destdir prefix")?;
let rel_path_str = rel_path.to_string_lossy().to_string();
if is_skipped_install_path(&rel_path_str) {
continue;
}
let dest_path = rootfs.join(rel_path);
if !dest_path.exists() {
fs::create_dir_all(&dest_path)?;
apply_unix_mode(&dest_path, &src_path.symlink_metadata()?)?;
}
staged_paths.insert(rel_path_str);
}
// Copy in new files.
for entry in WalkDir::new(destdir).into_iter().filter_map(|e| e.ok()) {
let src_path = entry.path();
let metadata = src_path
.symlink_metadata()
.context("Failed to get metadata")?;
let file_type = metadata.file_type();
// We want to install files AND symlinks (to anything)
if !file_type.is_file() && !file_type.is_symlink() {
continue;
}
let rel_path = src_path
.strip_prefix(destdir)
.context("Failed to strip destdir prefix")?
.to_string_lossy()
.to_string();
if is_skipped_install_path(&rel_path) {
continue;
}
let keep_match = if keep_set.contains(&rel_path) {
true
} else {
keep_rules.iter().any(|m| m.matches(&rel_path))
};
let keep_as_depotnew = keep_match && rootfs.join(&rel_path).exists();
let install_rel_path = if keep_as_depotnew {
format!("{}.depotnew", rel_path)
} else {
rel_path.clone()
};
let dest_path = rootfs.join(&install_rel_path);
if let Some(parent) = dest_path.parent() {
fs::create_dir_all(parent)?;
}
if let Ok(dest_meta) = dest_path.symlink_metadata() {
let backup_path = tx.backup_path(&install_rel_path);
if dest_meta.file_type().is_dir() {
let can_relocate = file_type.is_symlink()
&& can_relocate_directory_for_symlink_swap(
rootfs,
&install_rel_path,
src_path,
)?;
if !remove_set.contains(install_rel_path.as_str()) && !can_relocate {
anyhow::bail!(
"Refusing to replace existing directory with packaged file/symlink: {}",
install_rel_path
);
}
backup_existing_path(&dest_path, &backup_path, &install_rel_path)?;
tx.backed_up.push(install_rel_path.clone());
remove_obsolete_children_for_dir(
&mut tx,
rootfs,
&install_rel_path,
remove_paths,
)?;
if file_type.is_symlink() {
tx.relocate_directory_for_symlink_swap(&install_rel_path)?;
}
} else {
backup_existing_path(&dest_path, &backup_path, &install_rel_path)?;
tx.backed_up.push(install_rel_path.clone());
}
} else {
tx.created.push(install_rel_path.clone());
}
// Install new file/symlink
// Remove destination if it exists (we backed it up) so we can overwrite
if let Ok(dest_meta) = dest_path.symlink_metadata() {
if dest_meta.file_type().is_dir() {
let relocated_for_symlink_swap =
tx.relocated.iter().any(|rel| rel == &install_rel_path);
if !remove_set.contains(install_rel_path.as_str())
&& !relocated_for_symlink_swap
{
anyhow::bail!(
"Refusing to replace existing directory with packaged file/symlink: {}",
install_rel_path
);
}
if !is_directory_empty(&dest_path)? {
anyhow::bail!(
"Refusing to replace existing non-empty directory with packaged file/symlink: {}",
install_rel_path
);
}
fs::remove_dir(&dest_path)?;
} else {
fs::remove_file(&dest_path)?;
}
}
if file_type.is_symlink() {
let target = fs::read_link(src_path)
.with_context(|| format!("Failed to read staged symlink {}", rel_path))?;
std::os::unix::fs::symlink(target, &dest_path)
.with_context(|| format!("Failed to create symlink: {}", install_rel_path))?;
tx.replay_relocated_dir_if_present(&install_rel_path)?;
} else {
let hardlink_key = if keep_as_depotnew {
None
} else {
hardlink_key(&metadata)
};
if let Some(first_rel_path) =
hardlink_key.and_then(|key| installed_hardlinks.get(&key))
{
let first_path = rootfs.join(first_rel_path);
fs::hard_link(&first_path, &dest_path).with_context(|| {
format!(
"Failed to install hardlink: {} -> {}",
install_rel_path, first_rel_path
)
})?;
} else {
fs::copy(src_path, &dest_path)
.with_context(|| format!("Failed to install: {}", install_rel_path))?;
apply_unix_mode(&dest_path, &metadata)?;
if let Some(key) = hardlink_key {
installed_hardlinks.insert(key, install_rel_path.clone());
}
}
}
staged_paths.insert(install_rel_path);
}
// Remove obsolete files/directories left behind by the previous version.
for rel in remove_paths {
if staged_paths.contains(rel) || tx.removed.iter().any(|removed| removed == rel) {
continue;
}
let _ = backup_and_remove_obsolete_path(&mut tx, rootfs, rel, false)?;
}
Ok(())
})();
if let Err(e) = result {
let _ = tx.rollback();
return Err(e);
}
Ok(tx)
}