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//! Index loading: `Index::open`, `open_with_lock`, and `open_inner`.
use std::collections::HashMap;
use std::path::Path;
use std::sync::Arc;
use arc_swap::ArcSwap;
use roaring::RoaringBitmap;
use super::{snapshot, Index, MAX_TOTAL_DOCS};
use crate::index::manifest::Manifest;
use crate::index::overlay::{OverlayView, PendingEdits};
use crate::index::segment::MmapSegment;
use crate::index::snapshot::BaseSegments;
use crate::path::PathIndex;
use crate::{Config, IndexError};
impl Index {
/// Open an existing index. Loads the manifest, mmaps base segments,
/// and rebuilds the path index from segment doc tables.
pub fn open(config: Config) -> Result<Self, IndexError> {
// Shared lock: multiple readers are fine, but blocks an active build.
let lock_path = config.index_dir.join("lock");
let dir_lock = std::fs::OpenOptions::new()
.read(true)
.write(true)
.create(true)
.truncate(false)
.open(&lock_path)?;
dir_lock
.try_lock_shared()
.map_err(|_| IndexError::LockConflict(config.index_dir.clone()))?;
// Security: reject (or warn about) index directories readable/writable
// by group/other. Permissive modes allow concurrent ftruncate() races
// (SIGBUS DoS) and crafted-file injection. New builds enforce 0700 via
// build_index(); this check catches pre-existing indexes.
#[cfg(unix)]
{
use std::os::unix::fs::MetadataExt;
if let Ok(meta) = std::fs::metadata(&config.index_dir) {
if meta.mode() & 0o077 != 0 {
if config.strict_permissions {
return Err(IndexError::CorruptIndex(format!(
"index dir {:?} has mode {:04o}; expected 0700 (no group/other bits). \
group/other access enables SIGBUS DoS via ftruncate. \
Fix with: chmod 700, or set strict_permissions=false",
config.index_dir,
meta.mode() & 0o777,
)));
} else if config.verbose {
eprintln!(
"syntext: warning: index dir {:?} has mode {:04o}; \
recommend chmod 700 to prevent injection and SIGBUS DoS",
config.index_dir,
meta.mode() & 0o777,
);
}
}
}
}
Self::open_inner(config, dir_lock)
}
/// Open an existing index using an already-held directory lock.
/// Called by `build_index` after downgrading the exclusive lock to shared,
/// avoiding the gap where a competing build could start.
pub(super) fn open_with_lock(
config: Config,
dir_lock: std::fs::File,
) -> Result<Self, IndexError> {
// Lock is already held (shared) and permissions were verified by
// build_index, so skip both checks.
Self::open_inner(config, dir_lock)
}
/// Shared implementation for `open` and `open_with_lock`.
fn open_inner(config: Config, dir_lock: std::fs::File) -> Result<Self, IndexError> {
let manifest = Manifest::load(&config.index_dir)?;
let scan_threshold = manifest
.scan_threshold_fraction
.unwrap_or(0.10)
.clamp(0.01, 0.50);
let mut base_segments: Vec<MmapSegment> = Vec::new();
let mut segment_base_ids: Vec<u32> = Vec::new();
let mut base_doc_paths: Vec<Option<std::path::PathBuf>> = Vec::new();
let mut all_paths: Vec<std::path::PathBuf> = Vec::new();
let mut path_doc_ids: HashMap<std::path::PathBuf, Vec<u32>> = HashMap::new();
let mut max_global_id_exclusive: u32 = 0;
let mut prev_segment_end: u32 = 0;
for seg_ref in &manifest.segments {
let seg = if !seg_ref.dict_filename.is_empty() && !seg_ref.post_filename.is_empty() {
// v3: split .dict + .post files. Validate both filenames.
for filename in [&seg_ref.dict_filename, &seg_ref.post_filename] {
if filename.contains('/')
|| filename.contains('\\')
|| filename.contains("..")
|| Path::new(filename).is_absolute()
{
return Err(IndexError::CorruptIndex(format!(
"invalid segment filename in manifest: {:?}",
filename
)));
}
}
let dict_path = config.index_dir.join(&seg_ref.dict_filename);
let post_path = config.index_dir.join(&seg_ref.post_filename);
MmapSegment::open_split(&dict_path, &post_path)?
} else {
// v2: single combined .seg file. Accept `dict_filename` as a
// compatibility fallback for older transitional manifests.
let open_filename = if !seg_ref.filename.is_empty() {
&seg_ref.filename
} else {
&seg_ref.dict_filename
};
if open_filename.contains('/')
|| open_filename.contains('\\')
|| open_filename.contains("..")
|| Path::new(open_filename).is_absolute()
{
return Err(IndexError::CorruptIndex(format!(
"invalid segment filename in manifest: {:?}",
open_filename
)));
}
let seg_path = config.index_dir.join(open_filename);
MmapSegment::open(&seg_path)?
};
// Security: check the per-segment doc count against MAX_TOTAL_DOCS
// BEFORE iterating the segment's doc entries and inserting them into
// base_doc_paths and path_doc_ids.
//
// Without this early check, a crafted segment with doc_count close to
// MAX_TOTAL_DOCS and path_len = 65535 per entry could force several
// gigabytes of PathBuf allocations into path_doc_ids before the
// post-loop guard triggers. The per-segment check caps the allocation
// to at most one segment's worth of entries at a time.
let segment_base_id = seg_ref.base_doc_id.unwrap_or(prev_segment_end);
if segment_base_id < prev_segment_end {
return Err(IndexError::CorruptIndex(format!(
"segment base_doc_id {} regresses previous end {}",
segment_base_id, prev_segment_end
)));
}
let new_global_id_exclusive =
segment_base_id
.checked_add(seg.doc_count)
.ok_or(IndexError::DocIdOverflow {
base_doc_count: segment_base_id,
overlay_docs: 0,
})?;
if new_global_id_exclusive > MAX_TOTAL_DOCS {
return Err(IndexError::CorruptIndex(format!(
"segment would push total docs to {new_global_id_exclusive}, exceeds safety limit of {MAX_TOTAL_DOCS}"
)));
}
segment_base_ids.push(segment_base_id);
// Iterate using local 0-based indices (0..seg.doc_count).
for local_id in 0..seg.doc_count {
if let Some(doc) = seg.get_doc(local_id) {
let expected_doc_id = segment_base_id.saturating_add(local_id);
if doc.doc_id != expected_doc_id {
return Err(IndexError::CorruptIndex(format!(
"segment doc_id {} does not match expected {}",
doc.doc_id, expected_doc_id
)));
}
let doc_idx = doc.doc_id as usize;
if base_doc_paths.len() <= doc_idx {
base_doc_paths.resize(doc_idx + 1, None);
}
if base_doc_paths[doc_idx].is_some() {
return Err(IndexError::CorruptIndex(format!(
"duplicate base doc_id {} across segments",
doc.doc_id
)));
}
base_doc_paths[doc_idx] = Some(doc.path.clone());
path_doc_ids
.entry(doc.path.clone())
.or_default()
.push(doc.doc_id);
all_paths.push(doc.path);
}
}
prev_segment_end = new_global_id_exclusive;
max_global_id_exclusive = max_global_id_exclusive.max(new_global_id_exclusive);
base_segments.push(seg);
}
all_paths.sort_unstable();
all_paths.dedup();
let path_index = PathIndex::build(&all_paths);
let base = Arc::new(BaseSegments {
segments: base_segments,
base_ids: segment_base_ids,
base_doc_paths,
path_doc_ids,
});
// Final sanity check: the per-segment guard above should have caught
// any overage, but verify the accumulated total before the vec allocation.
if max_global_id_exclusive > MAX_TOTAL_DOCS {
return Err(IndexError::CorruptIndex(format!(
"manifest claims {max_global_id_exclusive} total docs, exceeds safety limit of {MAX_TOTAL_DOCS}"
)));
}
let mut base_doc_to_file_id = vec![u32::MAX; max_global_id_exclusive as usize];
for (gid, path) in base.base_doc_paths.iter().enumerate() {
if let Some(path) = path {
if let Some(fid) = path_index.file_id(path) {
base_doc_to_file_id[gid] = fid;
}
}
}
let base_doc_to_file_id = Arc::new(base_doc_to_file_id);
let snapshot = Arc::new(snapshot::new_snapshot(
base,
OverlayView::empty(),
RoaringBitmap::new(),
path_index,
base_doc_to_file_id,
HashMap::new(),
scan_threshold,
));
// Open symbol index if it exists on disk.
#[cfg(feature = "symbols")]
let symbol_index = {
let db_path = config.index_dir.join("symbols.db");
if db_path.exists() {
crate::symbol::SymbolIndex::open(&db_path)
.ok()
.map(std::sync::Arc::new)
} else {
None
}
};
let canonical_root = std::fs::canonicalize(&config.repo_root)?;
Ok(Index {
config,
snapshot: ArcSwap::from(snapshot),
pending: PendingEdits::new(),
_dir_lock: dir_lock,
canonical_root,
#[cfg(feature = "symbols")]
symbol_index,
})
}
}