Files
nxdns/src/filter/manager.zig
T

1955 lines
80 KiB
Zig

//! The blocklist manager (PLAN §4): the compiled files under
//! `<data_dir>/blocklists/`, the refresh that produces them, the metadata
//! columns it writes back, the snapshot built from them and the swap that
//! publishes it.
//!
//! This is the only file in this milestone that touches both the database and
//! the filesystem. Everything it composes — the parsers, the compiler, the
//! domain sets, the rule sets and the snapshot — is pure and testable without
//! either.
//!
//! **The swap is an `std.Io.RwLock`, not a lock-free pointer.** PLAN §7.3 says
//! "readers lock-free"; this is a deliberate deviation. Freeing the old
//! snapshot without a lock needs epoch-based reclamation or hazard pointers: a
//! class of code that is very hard to get right and impossible to test
//! convincingly, bought for a household resolver whose target is 100 qps. A
//! shared lock held for the microseconds of one `evaluate` costs an uncontended
//! atomic pair; the writer takes the exclusive lock only on a swap, which
//! happens on refresh. The old snapshot is freed *after* `unlock` returns, and
//! the `Handle` API makes "do not retain the pointer" the only shape a caller
//! can write.
//!
//! The same lock guards the status table, which is written from the refresh
//! task and read by the API. Both critical sections are short and hold no
//! socket and no file, so the uncancelable lock forms are used: a lock this
//! code takes is always released within a few instructions.
//!
//! A second lock, `writer_lock`, serializes the writers against each other:
//! `reload`, `refreshSource`, `refreshAll`, the startup pass and
//! `pruneOrphans`. Two concurrent reloads would otherwise compute the same
//! generation and each destroy a snapshot the other had just published, and two
//! concurrent refreshes would share the fetcher's buffers and, for one source,
//! the same `.raw.tmp` / `.list.tmp` / `.wild.tmp` paths. It is held across
//! downloads and compiles, so it is a plain mutex rather than the RCU lock:
//! readers must never wait behind a refresh. The public entry points take it;
//! the `*Locked` bodies assume it and never take it again, because it is not
//! reentrant.
const std = @import("std");
const Allocator = std.mem.Allocator;
const model = @import("../config/model.zig");
const db = @import("../storage/db.zig");
const clients_repo = @import("../storage/repositories/clients_repo.zig");
const groups_repo = @import("../storage/repositories/groups_repo.zig");
const rules_repo = @import("../storage/repositories/rules_repo.zig");
const sources_repo = @import("../storage/repositories/sources_repo.zig");
const disk_monitor = @import("../storage/disk_monitor.zig");
const compiler = @import("compiler.zig");
const fetcher = @import("fetcher.zig");
const matcher = @import("matcher.zig");
const parsers = @import("parsers.zig");
const log = std.log.scoped(.blocklist_manager);
const Sha256 = std.crypto.hash.sha2.Sha256;
/// `SourceStatus.last_error` is fixed-size so the failure path allocates
/// nothing.
pub const max_error_len: usize = 128;
/// `SourceStatus.url` is fixed-size so a copied status borrows nothing. A
/// blocklist url longer than this is truncated in the status only; the row
/// keeps it whole.
pub const max_url_len: usize = 255;
/// A compiled body larger than this is refused at load. A source that reaches
/// it produced more than `fetcher.max_body_bytes` of names, which cannot
/// happen from a download this fetcher performed.
pub const max_compiled_bytes: usize = 128 * 1024 * 1024;
/// Buffer size for every file stream this file opens. One buffer is live per
/// stage, and the stages do not overlap.
const io_buf_len: usize = 64 * 1024;
/// Holds the sniff sample: `parsers.sample_lines` lines of at most
/// `compiler.max_line_len` bytes, each with its newline. A fixed byte window
/// would be spent by a handful of legal 4096-byte comment lines and the format
/// would then be decided by almost no data.
const sample_buf_len: usize = parsers.sample_lines * (compiler.max_line_len + 1);
/// `<id>` is at most 20 characters and the longest suffix is `.list.tmp`.
const name_buf_len: usize = 48;
pub const Paths = struct {
/// `<data_dir>`, owned by the caller and left open for the manager's life.
dir: std.Io.Dir,
subdir: []const u8 = "blocklists",
};
/// Where one source stands. `.never_fetched` is the state of a source that has
/// no compiled files and no stored checksum, which is a fresh install rather
/// than a failure. `.no_valid_entries` is a download that compiled cleanly and
/// yielded nothing usable — an error page or a compressed body, not a
/// blocklist.
pub const State = enum {
ok,
never_fetched,
fetch_failed,
compile_failed,
no_valid_entries,
load_failed,
/// Whether this state was recorded by a refresh rather than by a load.
/// A load outcome never overwrites one: the files a reload just read are
/// exactly the files the failed refresh could not replace, and the operator
/// still has to see why the update did not land. `SourceStatus.loaded`
/// carries the other half — whether the source is filtering at all.
pub fn isRefreshFailure(self: State) bool {
return switch (self) {
.fetch_failed, .compile_failed, .no_valid_entries => true,
.ok, .never_fetched, .load_failed => false,
};
}
};
/// A status is a value with no borrowed memory, so a copy handed to the API
/// outlives every reload. The url is held inline for that reason.
pub const SourceStatus = struct {
id: i64,
state: State = .never_fetched,
/// Whether this source's compiled files were read into the most recent
/// snapshot build — that is, whether it is filtering right now. `state`
/// describes the most recent attempt to *produce* those files, which is a
/// different fact: a source whose refresh failed keeps serving what the
/// refresh did not replace, and reads `.fetch_failed` with `loaded` set.
loaded: bool = false,
last_attempt: i64 = 0,
last_success: i64 = 0,
counts: compiler.Counts = .{},
/// A display copy of the source url, truncated at `max_url_len`. The whole
/// url is in the `blocklist_sources` row this status shares an `id` with.
url: [max_url_len]u8 = @splat(0),
url_len: u8 = 0,
last_error: [max_error_len]u8 = @splat(0),
last_error_len: u8 = 0,
pub fn errorText(self: *const SourceStatus) []const u8 {
return self.last_error[0..self.last_error_len];
}
pub fn urlText(self: *const SourceStatus) []const u8 {
return self.url[0..self.url_len];
}
fn setUrl(self: *SourceStatus, url: []const u8) void {
const kept = @min(url.len, max_url_len);
@memcpy(self.url[0..kept], url[0..kept]);
@memset(self.url[kept..], 0);
self.url_len = @intCast(kept);
}
fn fail(self: *SourceStatus, state: State, text: []const u8) void {
self.state = state;
const kept = @min(text.len, max_error_len);
@memcpy(self.last_error[0..kept], text[0..kept]);
@memset(self.last_error[kept..], 0);
self.last_error_len = @intCast(kept);
}
fn succeed(self: *SourceStatus, at: i64, counts: compiler.Counts) void {
self.state = .ok;
self.counts = counts;
self.last_success = at;
self.last_error = @splat(0);
self.last_error_len = 0;
}
};
/// The header every compiled file carries, ahead of the body. The `sha256`
/// covers the `.list` body followed by the `.wild` body and **not** the header,
/// so it stays stable across a refetch of unchanged content while
/// `fetched_at` moves.
pub const Header = struct {
url: []const u8,
format: parsers.Format,
fetched_at: i64,
counts: compiler.Counts,
/// 64 lowercase hex characters.
checksum: []const u8,
pub fn write(self: Header, w: *std.Io.Writer) std.Io.Writer.Error!void {
try w.writeAll("# nxdns blocklist\n");
try w.print("# url {s}\n", .{self.url});
try w.print("# format {s}\n", .{@tagName(self.format)});
try w.print("# fetched_at {d}\n", .{self.fetched_at});
try w.print("# domains {d}\n", .{self.counts.domains});
try w.print("# wildcards {d}\n", .{self.counts.wildcards});
try w.print("# skipped_regex {d}\n", .{self.counts.skipped_regex});
try w.print("# skipped_unsupported {d}\n", .{self.counts.skipped_unsupported});
try w.print("# invalid {d}\n", .{self.counts.invalid});
try w.print("# sha256 {s}\n", .{self.checksum});
}
};
/// The body of a compiled file: everything after the leading `#` lines. A file
/// with no header is all body, which is what makes a hand-written fixture a
/// legal compiled file.
pub fn stripHeader(bytes: []const u8) []const u8 {
var rest = bytes;
while (rest.len != 0 and rest[0] == '#') {
const newline = std.mem.indexOfScalar(u8, rest, '\n') orelse return rest[rest.len..];
rest = rest[newline + 1 ..];
}
return rest;
}
pub const Manager = struct {
gpa: Allocator,
database: *db.Db,
paths: Paths,
fetcher: *fetcher.Fetcher,
update: model.BlocklistUpdate,
/// Bounds one download. `std.http.Client` has no per-request deadline, so
/// the fetch runs under `io.concurrent` against a sleep of this length.
total_budget: std.Io.Clock.Duration,
lock: std.Io.RwLock,
/// Serializes the writers against each other. Never taken by a reader.
writer_lock: std.Io.Mutex,
current: ?*matcher.Snapshot,
generation: u64,
statuses: []SourceStatus,
/// Owns the `statuses` table. The entries themselves borrow nothing.
status_arena: std.heap.ArenaAllocator,
/// The §11.6 disk gate (ruling 17). Set by the composition root after
/// `init` and before `runScheduler` starts; null disables gating, which is
/// what every test and `nxdns check` want. Only the scheduler consults it —
/// see `refreshGated`.
monitor: ?*disk_monitor.Monitor = null,
/// Scheduled refresh passes skipped by the disk gate. Phase 8's health
/// rollup reads it through `refreshesGated`.
refreshes_gated: std.atomic.Value(u64) = .init(0),
pub const Error = error{
OutOfMemory,
Canceled,
/// A filesystem operation on the blocklist directory failed. The
/// concrete cause is logged at `warn` where it happens: this taxonomy
/// would otherwise carry two dozen members no caller can act on
/// differently.
FileSystem,
/// The `groups` table changed between listing the groups and reading
/// their ids. Retrying the reload is the answer, and the caller is the
/// only one that can decide to.
GroupSetChanged,
} || db.Error || matcher.Snapshot.Error;
/// The result is not copyable afterwards: `status_arena` and `lock` are
/// addressed through `self`.
pub fn init(
gpa: Allocator,
database: *db.Db,
paths: Paths,
fetcher_ptr: *fetcher.Fetcher,
update: model.BlocklistUpdate,
total_budget: std.Io.Clock.Duration,
) Error!Manager {
return .{
.gpa = gpa,
.database = database,
.paths = paths,
.fetcher = fetcher_ptr,
.update = update,
.total_budget = total_budget,
.lock = .init,
.writer_lock = .init,
.current = null,
.generation = 0,
.statuses = &.{},
.status_arena = .init(gpa),
};
}
pub fn deinit(self: *Manager, io: std.Io) void {
self.lock.lockUncancelable(io);
const old = self.current;
self.current = null;
self.statuses = &.{};
self.lock.unlock(io);
if (old) |snapshot| destroySnapshot(self.gpa, snapshot);
self.status_arena.deinit();
self.* = undefined;
}
/// Reader side of the swap. The handle holds a shared lock: release it, and
/// do not retain `snapshot` afterwards.
pub const Handle = struct {
snapshot: *const matcher.Snapshot,
manager: *Manager,
pub fn release(self: Handle, io: std.Io) void {
self.manager.lock.unlockShared(io);
}
};
/// `null` before the first successful `reload`. The caller answers
/// SERVFAIL, or forwards unfiltered, on its own policy — this file does not
/// decide that.
pub fn acquire(self: *Manager, io: std.Io) ?Handle {
self.lock.lockSharedUncancelable(io);
const snapshot = self.current orelse {
self.lock.unlockShared(io);
return null;
};
return .{ .snapshot = snapshot, .manager = self };
}
/// Copies the status table for the API and for `nxdns check`. Returns the
/// number of entries written, which is `min(out.len, source count)`.
///
/// The copies are self-contained: `SourceStatus` holds its url and its
/// error text inline, so the caller may keep them for as long as it likes
/// and a concurrent reload cannot pull memory out from under them.
pub fn statusSnapshot(self: *Manager, io: std.Io, out: []SourceStatus) usize {
self.lock.lockSharedUncancelable(io);
defer self.lock.unlockShared(io);
const kept = @min(out.len, self.statuses.len);
@memcpy(out[0..kept], self.statuses[0..kept]);
return kept;
}
// -----------------------------------------------------------------------
// reload
// -----------------------------------------------------------------------
/// Reads the database and every compiled file, builds a snapshot and swaps
/// it in.
///
/// A source whose compiled files are missing, unreadable or checksum
/// mismatched is marked `.load_failed` and left out of the snapshot rather
/// than failing the whole reload: one bad file must not cost the operator
/// every other list. `runScheduler` refreshes exactly those sources, so the
/// state is recorded, surfaced and repaired, never silently accepted.
///
/// A body that is present and checksum-clean but malformed fails the build
/// (`error.NotSorted`), and the previously published snapshot keeps
/// serving: nothing is swapped until the new snapshot exists. The status
/// table keeps describing that snapshot too — the table is rebuilt off to
/// the side and the load findings are written into it there, so a reload
/// that never publishes changes neither.
pub fn reload(self: *Manager, io: std.Io) Error!void {
self.writer_lock.lockUncancelable(io);
defer self.writer_lock.unlock(io);
return self.reloadLocked(io);
}
fn reloadLocked(self: *Manager, io: std.Io) Error!void {
var rows = try sources_repo.listSourceRows(self.database, self.gpa);
defer rows.deinit(self.gpa);
defer sources_repo.freeSourceRows(self.gpa, rows.items);
// The table this reload will publish, built where no reader can see it.
// It is installed in the swap below or freed unpublished, so a reload
// that fails leaves the previous table describing the previous
// snapshot — including the entry of a source deleted from the database,
// which that snapshot still enforces.
var candidate: ?StatusTable = try self.buildStatusTable(io, rows.items);
errdefer if (candidate) |*table| table.deinit();
var dir = try self.openDir(io, .{});
defer dir.close(io);
const sources = try self.gpa.alloc(model.BlocklistSource, rows.items.len);
defer self.gpa.free(sources);
const source_ids = try self.gpa.alloc(i64, rows.items.len);
defer self.gpa.free(source_ids);
const compiled = try self.gpa.alloc(?matcher.Snapshot.Compiled, rows.items.len);
defer self.gpa.free(compiled);
// The file contents outlive the header stripping and are freed once the
// snapshot has copied what it needs into its own arena.
var bodies: std.ArrayList([]u8) = .empty;
defer {
for (bodies.items) |body| self.gpa.free(body);
bodies.deinit(self.gpa);
}
// What this reload found, per source. It is applied to the status table
// only if the snapshot it describes is published: everything below here
// can still fail, and a status table describing a snapshot nobody
// serves is worse than one describing the previous one.
const outcomes = try self.gpa.alloc(LoadOutcome, rows.items.len);
defer self.gpa.free(outcomes);
var loaded: usize = 0;
for (rows.items, sources, source_ids, compiled, outcomes) |row, *source, *source_id, *slot, *outcome| {
source_id.* = row.id;
// `is_suggested` is a UI hint the snapshot never reads.
source.* = .{ .url = row.url, .name = row.name, .enabled = row.enabled };
outcome.* = if (row.enabled) try self.loadSource(io, dir, row, &bodies) else .disabled;
switch (outcome.*) {
.loaded => |body| {
slot.* = body;
loaded += 1;
},
// Not loadable and therefore not enforced. Saying so here is
// what keeps `Snapshot.build`'s `MissingCompiledSource` for the
// case it is meant for: a caller that forgot to read a body.
.disabled, .failed => {
slot.* = null;
source.enabled = false;
},
}
}
var groups = try groups_repo.listGroups(self.database, self.gpa);
defer groups.deinit(self.gpa);
defer groups_repo.freeGroups(self.gpa, groups.items);
const group_ids = try self.groupIds(groups.items);
defer self.gpa.free(group_ids);
var group_sources = try groups_repo.listGroupSources(self.database, self.gpa);
defer group_sources.deinit(self.gpa);
defer groups_repo.freeGroupSources(self.gpa, group_sources.items);
var rule_rows = try rules_repo.listRules(self.database, self.gpa);
defer rule_rows.deinit(self.gpa);
defer rules_repo.freeRules(self.gpa, rule_rows.items);
var clients = try clients_repo.listClients(self.database, self.gpa);
defer clients.deinit(self.gpa);
defer clients_repo.freeClients(self.gpa, clients.items);
var prefixes = try clients_repo.listClientPrefixes(self.database, self.gpa);
defer prefixes.deinit(self.gpa);
defer clients_repo.freeClientPrefixes(self.gpa, prefixes.items);
// Query names are attacker-supplied, so a fixed seed would make
// probe-chain flooding computable offline.
var seed_bytes: [8]u8 = undefined;
io.random(&seed_bytes);
const generation = self.generation + 1;
const snapshot = try self.gpa.create(matcher.Snapshot);
errdefer self.gpa.destroy(snapshot);
snapshot.* = try matcher.Snapshot.build(self.gpa, .{
.groups = groups.items,
.group_ids = group_ids,
.group_sources = group_sources.items,
.sources = sources,
.source_ids = source_ids,
.rules = rule_rows.items,
.clients = clients.items,
.prefixes = prefixes.items,
.compiled = compiled,
.seed = std.mem.readInt(u64, &seed_bytes, .little),
.generation = generation,
});
// Read before the swap: once `current` points at it, this snapshot
// belongs to the readers and to whichever writer replaces it next.
const memory_bytes = snapshot.memoryBytes();
// The snapshot, the status table and the load facts land together, so a
// reader never sees a status table describing anything but the
// published snapshot.
self.lock.lockUncancelable(io);
const old = self.current;
self.current = snapshot;
self.generation = generation;
applyLoadOutcomes(candidate.?.items, rows.items, outcomes);
self.installStatuses(candidate.?);
candidate = null;
self.lock.unlock(io);
// After `unlock`: no reader can still hold the old snapshot here, and
// `writer_lock` keeps every other writer out of this sequence.
if (old) |previous| destroySnapshot(self.gpa, previous);
log.info("blocklist snapshot generation {d}: {d} of {d} sources loaded, {d} bytes", .{
generation,
loaded,
rows.items.len,
memory_bytes,
});
}
/// What one enabled source contributes to the snapshot being built. Nothing
/// here touches the status table: the outcome is data until the swap
/// commits it.
fn loadSource(
self: *Manager,
io: std.Io,
dir: std.Io.Dir,
row: sources_repo.SourceRow,
bodies: *std.ArrayList([]u8),
) Error!LoadOutcome {
const stored = row.checksum orelse
// No stored checksum means no successful compile has ever
// happened. A fresh install is here on every source.
return .{ .failed = .{ .state = .never_fetched, .text = "" } };
var list_buf: [name_buf_len]u8 = undefined;
var wild_buf: [name_buf_len]u8 = undefined;
const list_name = compiledName(&list_buf, row.id, ".list");
const wild_name = compiledName(&wild_buf, row.id, ".wild");
// Reserved before the reads, so neither buffer can be orphaned by a
// failing append: `bodies` owns each one from the moment it is read.
try bodies.ensureUnusedCapacity(self.gpa, 2);
const list_bytes = dir.readFileAlloc(io, list_name, self.gpa, .limited(max_compiled_bytes)) catch |err| {
if (err == error.OutOfMemory) return error.OutOfMemory;
return loadFailure(row, list_name, err);
};
bodies.appendAssumeCapacity(list_bytes);
const wild_bytes = dir.readFileAlloc(io, wild_name, self.gpa, .limited(max_compiled_bytes)) catch |err| {
if (err == error.OutOfMemory) return error.OutOfMemory;
return loadFailure(row, wild_name, err);
};
bodies.appendAssumeCapacity(wild_bytes);
const list_body = stripHeader(list_bytes);
const wild_body = stripHeader(wild_bytes);
// The checksum covers both bodies together, so a crash between the two
// `replace` calls — a new `.list` beside an old `.wild` — is caught
// here and refreshed, not served as a half-updated list.
if (!std.mem.eql(u8, stored, &bodyChecksum(list_body, wild_body))) {
log.warn("blocklist {s}: compiled files do not match the stored checksum", .{row.url});
return .{ .failed = .{ .state = .load_failed, .text = "ChecksumMismatch" } };
}
return .{ .loaded = .{ .list_body = list_body, .wild_body = wild_body } };
}
// -----------------------------------------------------------------------
// refresh
// -----------------------------------------------------------------------
/// Downloads, compiles and atomically replaces the compiled files of one
/// source, then writes its runtime columns.
///
/// Returns `true` only when the compiled files were replaced. Unchanged
/// content (equal checksum) and every recorded failure return `false`; the
/// reason for a failure is in the status table, not in the return value.
///
/// The status entry is found by row id, so a source added since the last
/// `reload` has nowhere to record its outcome. `refreshAll` syncs the table
/// before it refreshes anything, which is why it is the entry point Phase 8
/// and the scheduler use.
pub fn refreshSource(self: *Manager, io: std.Io, row: sources_repo.SourceRow) Error!bool {
self.writer_lock.lockUncancelable(io);
defer self.writer_lock.unlock(io);
return self.refreshSourceLocked(io, row);
}
fn refreshSourceLocked(self: *Manager, io: std.Io, row: sources_repo.SourceRow) Error!bool {
// The previous entry describes the compiled files that are still on
// disk, and a failed refresh leaves them serving. Starting from a blank
// status would erase `last_success` and the counters of a list that is
// still being enforced.
var status: SourceStatus = self.priorStatus(io, row.id) orelse .{ .id = row.id };
status.setUrl(row.url);
status.last_attempt = std.Io.Clock.real.now(io).toSeconds();
const replaced = try self.refreshOne(io, row, &status);
self.commitStatus(io, status);
return replaced;
}
/// Every enabled source, one at a time, then one `reload`. A failing source
/// never stops the pass: it would hide every source behind it.
///
/// This returns an error only when nothing could be done at all — out of
/// memory, an unreachable database, an unusable blocklist directory. A
/// source that failed to download or compile is a successful pass with a
/// non-`ok` status.
pub fn refreshAll(self: *Manager, io: std.Io) Error!void {
self.writer_lock.lockUncancelable(io);
defer self.writer_lock.unlock(io);
var rows = try sources_repo.listSourceRows(self.database, self.gpa);
defer rows.deinit(self.gpa);
defer sources_repo.freeSourceRows(self.gpa, rows.items);
try self.syncStatuses(io, rows.items);
for (rows.items) |row| {
if (!row.enabled) continue;
_ = try self.refreshSourceLocked(io, row);
}
return self.reloadLocked(io);
}
fn refreshOne(
self: *Manager,
io: std.Io,
row: sources_repo.SourceRow,
status: *SourceStatus,
) Error!bool {
var dir = try self.openDir(io, .{});
defer dir.close(io);
var raw_buf: [name_buf_len]u8 = undefined;
var list_tmp_buf: [name_buf_len]u8 = undefined;
var wild_tmp_buf: [name_buf_len]u8 = undefined;
const raw_name = compiledName(&raw_buf, row.id, ".raw.tmp");
const list_tmp = compiledName(&list_tmp_buf, row.id, ".list.tmp");
const wild_tmp = compiledName(&wild_tmp_buf, row.id, ".wild.tmp");
// Installed before the calls that create these files, not after: an
// `error.Canceled` or `error.OutOfMemory` returned straight out of
// `download` or `compileTo` would outrun a later `defer` and leave a
// temporary behind. Deleting a name that was never created is a no-op.
defer self.deleteQuietly(io, dir, raw_name);
defer self.deleteQuietly(io, dir, list_tmp);
defer self.deleteQuietly(io, dir, wild_tmp);
self.download(io, dir, raw_name, row.url) catch |err| switch (err) {
error.OutOfMemory => return error.OutOfMemory,
error.Canceled => return error.Canceled,
else => {
self.reportFetchFailure(row, status, err);
return false;
},
};
const format = self.detectFormat(io, dir, raw_name) catch |err| switch (err) {
error.OutOfMemory => return error.OutOfMemory,
error.Canceled => return error.Canceled,
else => {
self.reportCompileFailure(row, status, err);
return false;
},
};
const result = self.compileTo(io, dir, raw_name, format, list_tmp, wild_tmp) catch |err| switch (err) {
error.OutOfMemory => return error.OutOfMemory,
error.Canceled => return error.Canceled,
else => {
self.reportCompileFailure(row, status, err);
return false;
},
};
if (rejectedWithoutEntries(result.counts)) {
self.reportEmptyCompile(row, status, result.counts);
return false;
}
const now = std.Io.Clock.real.now(io).toSeconds();
// Recompiling identical content into new files would invalidate the
// snapshot for nothing. The files on disk must actually carry that
// content: if a reload found them corrupt and excluded the source, a
// re-download of unchanged upstream bytes is the one chance to repair
// them, and skipping the rewrite here would leave filtering off for
// good.
if (row.checksum) |stored| {
if (std.mem.eql(u8, stored, &result.checksum) and self.diskBodiesMatch(io, dir, row.id, stored)) {
try sources_repo.updateSourceStats(self.database, row.id, .{
.last_updated = now,
.domain_count = row.domain_count,
.wildcard_count = row.wildcard_count,
.skipped_regex_count = row.skipped_regex_count,
.checksum = stored,
});
status.succeed(now, result.counts);
return false;
}
}
const header: Header = .{
.url = row.url,
.format = format,
.fetched_at = now,
.counts = result.counts,
.checksum = &result.checksum,
};
self.publish(io, dir, row.id, header, list_tmp, wild_tmp) catch |err| switch (err) {
error.OutOfMemory => return error.OutOfMemory,
error.Canceled => return error.Canceled,
else => {
self.reportCompileFailure(row, status, err);
return false;
},
};
try sources_repo.updateSourceStats(self.database, row.id, .{
.last_updated = now,
.domain_count = result.counts.domains,
.wildcard_count = result.counts.wildcards,
.skipped_regex_count = result.counts.skipped_regex,
.checksum = &result.checksum,
});
status.succeed(now, result.counts);
return true;
}
/// The body goes to a temporary file, never to memory: `max_body_bytes` is
/// 64 MB and the memory budget has no room for it beside two snapshots.
fn download(
self: *Manager,
io: std.Io,
dir: std.Io.Dir,
raw_name: []const u8,
url: []const u8,
) !void {
const file = try dir.createFile(io, raw_name, .{ .permissions = .fromMode(0o600) });
defer file.close(io);
const buffer = try self.gpa.alloc(u8, io_buf_len);
defer self.gpa.free(buffer);
var fw = file.writer(io, buffer);
const result = self.fetchWithin(io, url, &fw.interface) catch |err| {
// `fetcher.Error.Unexpected` is what a failing sink surfaces as;
// the concrete cause is on this writer, which the fetcher does not
// own.
if (fw.err) |cause| return cause;
if (err == error.HttpStatus) {
if (self.fetcher.last_status) |status| {
log.warn("blocklist {s}: http status {d}", .{ url, @intFromEnum(status) });
}
}
return err;
};
try fw.interface.flush();
// The compile reads this file back; the bytes must be there, not in a
// buffer this function is about to drop.
try file.sync(io);
log.debug("blocklist {s}: downloaded {d} bytes", .{ url, result.bytes_read });
}
/// `std.http.Client` has no per-request deadline, so the whole exchange
/// races a sleep and the loser is canceled — milestone 3's pattern.
fn fetchWithin(
self: *Manager,
io: std.Io,
url: []const u8,
w: *std.Io.Writer,
) fetcher.Error!fetcher.Result {
var outcomes: [2]Outcome = undefined;
var race: std.Io.Select(Outcome) = .init(io, &outcomes);
defer race.cancelDiscard();
race.concurrent(.fetch, fetcher.Fetcher.fetch, .{ self.fetcher, io, url, w }) catch |err| switch (err) {
error.ConcurrencyUnavailable => return error.SystemResources,
};
race.concurrent(.expiry, expire, .{ io, self.total_budget }) catch |err| switch (err) {
error.ConcurrencyUnavailable => return error.SystemResources,
};
switch (try race.await()) {
.fetch => |result| return result,
.expiry => |result| {
// A canceled sleep means this task is being torn down, not that
// the download is slow.
try result;
return error.Timeout;
},
}
}
fn detectFormat(
self: *Manager,
io: std.Io,
dir: std.Io.Dir,
raw_name: []const u8,
) !parsers.Format {
const file = try dir.openFile(io, raw_name, .{});
defer file.close(io);
const buffers = try self.gpa.alloc(u8, io_buf_len + sample_buf_len);
defer self.gpa.free(buffers);
var fr = file.reader(io, buffers[0..io_buf_len]);
var sample: std.Io.Writer = .fixed(buffers[io_buf_len..]);
collectSample(&fr.interface, &sample) catch |err| switch (err) {
error.ReadFailed => return fr.err orelse err,
// `sample_buf_len` holds every line `collectSample` can emit, so a
// full buffer means the sample is complete.
error.WriteFailed => {},
};
return parsers.detectFormat(sample.buffered());
}
/// Compiles into two plain temporary files. The compiled bodies cannot go
/// straight into the final files: the header carries counts that only exist
/// once the whole input has been compiled, and the loader requires the
/// header first.
fn compileTo(
self: *Manager,
io: std.Io,
dir: std.Io.Dir,
raw_name: []const u8,
format: parsers.Format,
list_tmp: []const u8,
wild_tmp: []const u8,
) !compiler.Result {
const raw = try dir.openFile(io, raw_name, .{});
defer raw.close(io);
const list_file = try dir.createFile(io, list_tmp, .{ .permissions = .fromMode(0o600) });
defer list_file.close(io);
const wild_file = try dir.createFile(io, wild_tmp, .{ .permissions = .fromMode(0o600) });
defer wild_file.close(io);
const buffers = try self.gpa.alloc(u8, 3 * io_buf_len);
defer self.gpa.free(buffers);
var fr = raw.reader(io, buffers[0..io_buf_len]);
var list_w = list_file.writer(io, buffers[io_buf_len .. 2 * io_buf_len]);
var wild_w = wild_file.writer(io, buffers[2 * io_buf_len ..]);
const result = compiler.compile(
self.gpa,
&fr.interface,
format,
&list_w.interface,
&wild_w.interface,
) catch |err| switch (err) {
// `compiler.Error` names the direction; the concrete cause is on
// the stream that failed.
error.ReadFailed => return fr.err orelse err,
error.WriteFailed => return list_w.err orelse (wild_w.err orelse err),
else => return err,
};
try list_w.interface.flush();
try wild_w.interface.flush();
try list_file.sync(io);
try wild_file.sync(io);
return result;
}
/// Writes header + body into each final file through `createFileAtomic` +
/// `replace`, so a crash mid-write can never leave a half-list that would
/// load as a valid, shorter blocklist.
fn publish(
self: *Manager,
io: std.Io,
dir: std.Io.Dir,
id: i64,
header: Header,
list_tmp: []const u8,
wild_tmp: []const u8,
) !void {
const buffers = try self.gpa.alloc(u8, 2 * io_buf_len);
defer self.gpa.free(buffers);
var list_buf: [name_buf_len]u8 = undefined;
var wild_buf: [name_buf_len]u8 = undefined;
try publishOne(io, dir, compiledName(&list_buf, id, ".list"), list_tmp, header, buffers);
try publishOne(io, dir, compiledName(&wild_buf, id, ".wild"), wild_tmp, header, buffers);
}
fn publishOne(
io: std.Io,
dir: std.Io.Dir,
dest: []const u8,
body_name: []const u8,
header: Header,
buffers: []u8,
) !void {
const body = try dir.openFile(io, body_name, .{});
defer body.close(io);
var af = try dir.createFileAtomic(io, dest, .{
.permissions = .fromMode(0o600),
.replace = true,
});
defer af.deinit(io);
var fr = body.reader(io, buffers[0..io_buf_len]);
var fw = af.file.writer(io, buffers[io_buf_len..]);
header.write(&fw.interface) catch return fw.err orelse error.WriteFailed;
_ = fr.interface.streamRemaining(&fw.interface) catch
return fr.err orelse (fw.err orelse error.WriteFailed);
fw.interface.flush() catch return fw.err orelse error.WriteFailed;
// Before `replace`, which closes the file: the rename must publish
// durable bytes, not an empty file with the content still in the page
// cache.
try af.file.sync(io);
try af.replace(io);
}
/// Whether the two compiled files on disk hash to `expected`. A missing,
/// unreadable or corrupt file answers false, which sends the caller down
/// the rewrite path — the only path that can repair it.
fn diskBodiesMatch(self: *Manager, io: std.Io, dir: std.Io.Dir, id: i64, expected: []const u8) bool {
var list_buf: [name_buf_len]u8 = undefined;
var wild_buf: [name_buf_len]u8 = undefined;
const limit: std.Io.Limit = .limited(max_compiled_bytes);
const list_bytes = dir.readFileAlloc(io, compiledName(&list_buf, id, ".list"), self.gpa, limit) catch
return false;
defer self.gpa.free(list_bytes);
const wild_bytes = dir.readFileAlloc(io, compiledName(&wild_buf, id, ".wild"), self.gpa, limit) catch
return false;
defer self.gpa.free(wild_bytes);
return compiledBodiesMatch(list_bytes, wild_bytes, expected);
}
fn reportFetchFailure(
self: *Manager,
row: sources_repo.SourceRow,
status: *SourceStatus,
err: anyerror,
) void {
_ = self;
log.warn("blocklist {s}: download failed: {s}", .{ row.url, @errorName(err) });
status.fail(.fetch_failed, @errorName(err));
}
fn reportCompileFailure(
self: *Manager,
row: sources_repo.SourceRow,
status: *SourceStatus,
err: anyerror,
) void {
_ = self;
log.warn("blocklist {s}: compile failed: {s}", .{ row.url, @errorName(err) });
status.fail(.compile_failed, @errorName(err));
}
fn reportEmptyCompile(
self: *Manager,
row: sources_repo.SourceRow,
status: *SourceStatus,
counts: compiler.Counts,
) void {
_ = self;
var buf: [max_error_len]u8 = undefined;
const text = std.fmt.bufPrint(
&buf,
"NoValidEntries invalid={d} unsupported={d} long_lines={d}",
.{ counts.invalid, counts.skipped_unsupported, counts.long_lines },
) catch "NoValidEntries";
log.warn("blocklist {s}: {s}", .{ row.url, text });
status.fail(.no_valid_entries, text);
}
// -----------------------------------------------------------------------
// scheduling
// -----------------------------------------------------------------------
/// Loads at startup, refreshes only what needs it, then sleeps
/// `update.interval_hours` between full passes. Returns on
/// `error.Canceled`.
///
/// A cold restart must not re-download every list and a boot loop must not
/// become a download loop, so the startup pass refreshes a source only when
/// it has no usable compiled files or its `last_updated` is older than the
/// interval.
///
/// `update.enabled == false` stops after the startup pass; manual refresh
/// through `refreshAll` still works.
pub fn runScheduler(self: *Manager, io: std.Io) std.Io.Cancelable!void {
self.startupPass(io) catch |err| switch (err) {
error.Canceled => return error.Canceled,
else => log.warn("blocklist startup pass failed: {s}", .{@errorName(err)}),
};
if (!self.update.enabled) return;
// `boot` rather than `awake`: a box that suspends overnight should
// still see its daily interval elapse.
const interval: std.Io.Clock.Duration = .{
.raw = .fromSeconds(model.updateIntervalSeconds(self.update)),
.clock = .boot,
};
while (true) {
try interval.sleep(io);
if (self.refreshGated()) continue;
self.refreshAll(io) catch |err| switch (err) {
error.Canceled => return error.Canceled,
else => log.warn("blocklist refresh pass failed: {s}", .{@errorName(err)}),
};
}
}
/// The §11.6 gate, consulted by scheduled passes only (ruling 17). A
/// download writes tens of megabytes into the blocklist directory and the
/// compile writes as much again, which is exactly the "non-essential write"
/// a critically full disk must not take.
///
/// `reload` and `refreshAll` are deliberately not gated: both are operator
/// actions (the composition root's startup load, Phase 8's manual refresh),
/// and an operator who asks for a refresh on a full disk has asked for it.
///
/// Counting happens here, so a caller cannot skip a pass without recording
/// it. One `warn` line per skipped pass — at a 24-hour interval that is one
/// line a day, and the disk monitor already logs the state change itself.
fn refreshGated(self: *Manager) bool {
const monitor = self.monitor orelse return false;
if (monitor.writesAllowed()) return false;
_ = self.refreshes_gated.fetchAdd(1, .monotonic);
log.warn("free space is critical; skipping the scheduled blocklist refresh", .{});
return true;
}
/// Scheduled refresh passes the disk gate has skipped.
pub fn refreshesGated(self: *const Manager) u64 {
return self.refreshes_gated.load(.monotonic);
}
fn startupPass(self: *Manager, io: std.Io) Error!void {
self.writer_lock.lockUncancelable(io);
defer self.writer_lock.unlock(io);
// Ahead of the gate on purpose: loading the compiled files that already
// exist is a read. A full disk must not cost the household its
// filtering as well as its downloads.
try self.reloadLocked(io);
if (self.refreshGated()) return;
var rows = try sources_repo.listSourceRows(self.database, self.gpa);
defer rows.deinit(self.gpa);
defer sources_repo.freeSourceRows(self.gpa, rows.items);
const now = std.Io.Clock.real.now(io).toSeconds();
var refreshed = false;
for (rows.items) |row| {
if (!row.enabled) continue;
if (!self.needsRefresh(io, row, now)) continue;
if (try self.refreshSourceLocked(io, row)) refreshed = true;
}
if (refreshed) try self.reloadLocked(io);
}
fn needsRefresh(self: *Manager, io: std.Io, row: sources_repo.SourceRow, now: i64) bool {
self.lock.lockSharedUncancelable(io);
const state: State = state: {
for (self.statuses) |status| {
if (status.id == row.id) break :state status.state;
}
break :state .never_fetched;
};
self.lock.unlockShared(io);
if (state != .ok) return true;
const last = row.last_updated orelse return true;
return now - last >= model.updateIntervalSeconds(self.update);
}
// -----------------------------------------------------------------------
// orphans
// -----------------------------------------------------------------------
/// Deletes `<id>.list` and `<id>.wild` files whose id is no longer a
/// `blocklist_sources` row. Files of a live source are left alone,
/// whatever their state.
pub fn pruneOrphans(self: *Manager, io: std.Io) Error!void {
// A refresh in flight owns the temporaries of a live source; the sweep
// must not run beside one and decide from a half-written directory.
self.writer_lock.lockUncancelable(io);
defer self.writer_lock.unlock(io);
var rows = try sources_repo.listSourceRows(self.database, self.gpa);
defer rows.deinit(self.gpa);
defer sources_repo.freeSourceRows(self.gpa, rows.items);
var dir = try self.openDir(io, .{ .iterate = true });
defer dir.close(io);
// The names are collected first: `Entry.name` is invalidated by the
// next `next`, and deleting under an open cursor is not defined.
var doomed: std.ArrayList([]u8) = .empty;
defer {
for (doomed.items) |item| self.gpa.free(item);
doomed.deinit(self.gpa);
}
var it = dir.iterate();
while (true) {
const entry = it.next(io) catch |err| switch (err) {
error.Canceled => return error.Canceled,
else => {
log.warn("pruning blocklists: reading the directory failed: {s}", .{@errorName(err)});
return error.FileSystem;
},
} orelse break;
if (entry.kind != .file) continue;
const id = compiledId(entry.name) orelse continue;
if (containsId(rows.items, id)) continue;
try doomed.append(self.gpa, try self.gpa.dupe(u8, entry.name));
}
for (doomed.items) |name| {
self.deleteQuietly(io, dir, name);
log.info("pruned orphaned compiled file {s}", .{name});
}
}
// -----------------------------------------------------------------------
// internals
// -----------------------------------------------------------------------
/// Builds the status table for `rows`, carrying every existing entry over
/// by row id so a recorded failure survives. Nothing is published: the
/// caller either installs the result or frees it, which is what lets
/// `reloadLocked` decide only once its snapshot exists.
fn buildStatusTable(
self: *Manager,
io: std.Io,
rows: []const sources_repo.SourceRow,
) Error!StatusTable {
var fresh: std.heap.ArenaAllocator = .init(self.gpa);
errdefer fresh.deinit();
const arena = fresh.allocator();
// The published table is copied under the lock. Reading it unlocked
// would race the writer that replaces it — and the arena its entries
// live in is freed by whoever installs what this builds.
const previous = previous: {
self.lock.lockSharedUncancelable(io);
defer self.lock.unlockShared(io);
break :previous try arena.dupe(SourceStatus, self.statuses);
};
const table = try arena.alloc(SourceStatus, rows.len);
mergeStatuses(table, rows, previous);
return .{ .arena = fresh, .items = table };
}
/// Publishes a built table and frees the one it replaces. The caller holds
/// the exclusive lock, so no reader is inside the old table.
fn installStatuses(self: *Manager, table: StatusTable) void {
self.status_arena.deinit();
self.status_arena = table.arena;
self.statuses = table.items;
}
/// Rebuilds and publishes the status table from the current source set.
///
/// `refreshAll` calls this before it refreshes anything: a source added
/// since the last reload needs an entry to record its outcome in, and the
/// API has to see the pass advance while it runs. `reloadLocked` does not
/// call it — a reload publishes its table together with the snapshot that
/// table describes.
fn syncStatuses(self: *Manager, io: std.Io, rows: []const sources_repo.SourceRow) Error!void {
const table = try self.buildStatusTable(io, rows);
self.lock.lockUncancelable(io);
defer self.lock.unlock(io);
self.installStatuses(table);
}
/// The recorded entry for one source, or `null` when the table has none.
fn priorStatus(self: *Manager, io: std.Io, id: i64) ?SourceStatus {
self.lock.lockSharedUncancelable(io);
defer self.lock.unlockShared(io);
for (self.statuses) |entry| {
if (entry.id == id) return entry;
}
return null;
}
fn commitStatus(self: *Manager, io: std.Io, status: SourceStatus) void {
self.lock.lockUncancelable(io);
defer self.lock.unlock(io);
for (self.statuses) |*entry| {
if (entry.id != status.id) continue;
// `loaded` is the reload's fact, not the refresh's: the files this
// refresh wrote are not in a snapshot until the next reload reads
// them.
const loaded = entry.loaded;
entry.* = status;
entry.loaded = loaded;
return;
}
}
/// One id per group, in `listGroups` order.
fn groupIds(self: *Manager, groups: []const model.Group) Error![]i64 {
const out = try self.gpa.alloc(i64, groups.len);
errdefer self.gpa.free(out);
for (out, groups) |*slot, group| {
slot.* = try groups_repo.groupId(self.database, group.name) orelse
return error.GroupSetChanged;
}
return out;
}
fn openDir(self: *Manager, io: std.Io, options: std.Io.Dir.OpenOptions) Error!std.Io.Dir {
_ = self.paths.dir.createDirPathStatus(io, self.paths.subdir, .fromMode(0o700)) catch |err| switch (err) {
error.Canceled => return error.Canceled,
else => {
log.warn("creating {s} failed: {s}", .{ self.paths.subdir, @errorName(err) });
return error.FileSystem;
},
};
return self.paths.dir.openDir(io, self.paths.subdir, options) catch |err| switch (err) {
error.Canceled => return error.Canceled,
else => {
log.warn("opening {s} failed: {s}", .{ self.paths.subdir, @errorName(err) });
return error.FileSystem;
},
};
}
/// A temporary that cannot be removed is not a failure of the operation
/// that made it, but it is not nothing either: it is left visible.
fn deleteQuietly(self: *Manager, io: std.Io, dir: std.Io.Dir, name: []const u8) void {
_ = self;
dir.deleteFile(io, name) catch |err| switch (err) {
error.FileNotFound => {},
else => log.warn("deleting {s} failed: {s}", .{ name, @errorName(err) }),
};
}
};
/// A status table and the arena holding it. Until `installStatuses` takes it,
/// it is a candidate nobody can see, and `deinit` frees it whole.
const StatusTable = struct {
arena: std.heap.ArenaAllocator,
items: []SourceStatus,
fn deinit(self: *StatusTable) void {
self.arena.deinit();
self.items = &.{};
}
};
/// Fills `table` with one entry per row, carrying an entry of the same row id
/// over from `previous`. A source deleted since `previous` was built is gone; a
/// source added since starts blank. `previous` is only read, so the caller's
/// published table is untouched by this.
fn mergeStatuses(
table: []SourceStatus,
rows: []const sources_repo.SourceRow,
previous: []const SourceStatus,
) void {
for (table, rows) |*status, row| {
status.* = .{ .id = row.id };
for (previous) |prior| {
if (prior.id != row.id) continue;
status.* = prior;
break;
}
// After the carry-over: a url edited on the row wins over the one the
// prior entry recorded.
status.setUrl(row.url);
}
}
/// What one `reload` found for one source. The texts are static, so an outcome
/// borrows nothing and stays valid until the swap that commits it.
const LoadOutcome = union(enum) {
/// The source is switched off. Not in the snapshot, whatever it was before.
disabled,
/// Its compiled files are in the snapshot.
loaded: matcher.Snapshot.Compiled,
/// It is not in the snapshot, for this reason.
failed: struct { state: State, text: []const u8 },
};
fn loadFailure(row: sources_repo.SourceRow, file_name: []const u8, err: anyerror) LoadOutcome {
log.warn("blocklist {s}: reading {s} failed: {s}", .{ row.url, file_name, @errorName(err) });
return .{ .failed = .{ .state = .load_failed, .text = @errorName(err) } };
}
/// Writes one reload's findings into the status table. The caller holds the
/// exclusive lock: this runs inside the swap so the table and the published
/// snapshot describe the same thing.
///
/// `rows` and `outcomes` are parallel. A source with no entry is one the table
/// was not synced for, which cannot happen from `reloadLocked` and is skipped
/// rather than asserted, because the table is rebuilt by row id.
fn applyLoadOutcomes(
statuses: []SourceStatus,
rows: []const sources_repo.SourceRow,
outcomes: []const LoadOutcome,
) void {
for (rows, outcomes) |row, outcome| {
const entry = entryFor(statuses, row.id) orelse continue;
switch (outcome) {
// A source disabled since it last loaded is no longer filtering,
// and its recorded state describes files nothing reads.
.disabled => entry.loaded = false,
.loaded => {
entry.loaded = true;
// Two states survive a successful load. `.ok`, because a
// refresh in this process already filled the counters the
// compile produced and the three database columns are a subset
// of them. And any refresh failure, because the files that just
// loaded are exactly the ones the failed refresh could not
// replace, so the operator must still see why.
if (entry.state == .ok or entry.state.isRefreshFailure()) continue;
entry.succeed(row.last_updated orelse 0, .{
.domains = countOf(row.domain_count),
.wildcards = countOf(row.wildcard_count),
.skipped_regex = countOf(row.skipped_regex_count),
});
},
.failed => |reason| {
entry.loaded = false;
// The state follows only when nothing more informative is
// there: a refresh failure already says why the files are
// missing or stale, and `loaded` already says they are not
// filtering.
if (entry.state.isRefreshFailure()) continue;
entry.fail(reason.state, reason.text);
},
}
}
}
fn entryFor(statuses: []SourceStatus, id: i64) ?*SourceStatus {
for (statuses) |*entry| {
if (entry.id == id) return entry;
}
return null;
}
const Outcome = union(enum) {
fetch: fetcher.Error!fetcher.Result,
expiry: std.Io.Cancelable!void,
};
fn expire(io: std.Io, duration: std.Io.Clock.Duration) std.Io.Cancelable!void {
return duration.sleep(io);
}
/// A counter column read back from the database. It is `NOT NULL DEFAULT 0` and
/// only this file writes it, so a value outside `u32` means the row was edited
/// behind nxdns's back; the status reports 0 rather than trapping.
fn countOf(value: i64) u32 {
return std.math.cast(u32, value) orelse 0;
}
fn destroySnapshot(gpa: Allocator, snapshot: *matcher.Snapshot) void {
snapshot.deinit();
gpa.destroy(snapshot);
}
/// Copies the lines `parsers.detectFormat` would count — neither blank nor a
/// comment — until it has `parsers.sample_lines` of them, and writes them to
/// `w` newline-separated. Sampling by line rather than by a byte window is what
/// keeps a run of long comment lines from deciding the format: `detectFormat`
/// reads exactly these lines and ignores everything this drops.
///
/// A line over `compiler.max_line_len` is skipped, as the compiler skips it.
fn collectSample(r: *std.Io.Reader, w: *std.Io.Writer) error{ ReadFailed, WriteFailed }!void {
var considered: usize = 0;
while (considered < parsers.sample_lines) {
const raw = r.takeDelimiter('\n') catch |err| switch (err) {
// The stream is left unmodified here, so the line has to be stepped
// over or this loop never advances.
error.StreamTooLong => {
_ = r.discardDelimiterInclusive('\n') catch |discard_err| switch (discard_err) {
error.EndOfStream => return,
error.ReadFailed => return error.ReadFailed,
};
continue;
},
error.ReadFailed => return error.ReadFailed,
} orelse return;
if (raw.len > compiler.max_line_len) continue;
const line = std.mem.trim(u8, raw, &std.ascii.whitespace);
if (line.len == 0) continue;
if (parsers.isComment(line)) continue;
considered += 1;
try w.writeAll(line);
try w.writeByte('\n');
}
}
/// Whether two compiled files carry the bodies `expected` was taken over.
fn compiledBodiesMatch(list_bytes: []const u8, wild_bytes: []const u8, expected: []const u8) bool {
return std.mem.eql(u8, expected, &bodyChecksum(stripHeader(list_bytes), stripHeader(wild_bytes)));
}
/// A compile that produced no entry at all while rejecting lines is an error
/// page, a compressed body or a format the sniff got wrong — not a blocklist.
/// Publishing it would replace a working list with nothing and report `ok`. An
/// input that rejected nothing is an empty list, which is legal.
fn rejectedWithoutEntries(counts: compiler.Counts) bool {
if (counts.domains != 0 or counts.wildcards != 0) return false;
return counts.invalid != 0 or counts.skipped_unsupported != 0 or counts.long_lines != 0;
}
fn bodyChecksum(list_body: []const u8, wild_body: []const u8) [64]u8 {
var hasher = Sha256.init(.{});
hasher.update(list_body);
hasher.update(wild_body);
var digest: [Sha256.digest_length]u8 = undefined;
hasher.final(&digest);
return std.fmt.bytesToHex(digest, .lower);
}
fn compiledName(buf: *[name_buf_len]u8, id: i64, suffix: []const u8) []const u8 {
// An `i64` prints in at most 20 characters and the longest suffix is nine,
// so `name_buf_len` cannot be exceeded.
return std.fmt.bufPrint(buf, "{d}{s}", .{ id, suffix }) catch unreachable;
}
/// The source id a compiled file belongs to, or null when the name is not one
/// of ours. Temporary files are deliberately not matched: they belong to a
/// refresh that may still be running.
fn compiledId(file_name: []const u8) ?i64 {
const stem = if (std.mem.endsWith(u8, file_name, ".list"))
file_name[0 .. file_name.len - ".list".len]
else if (std.mem.endsWith(u8, file_name, ".wild"))
file_name[0 .. file_name.len - ".wild".len]
else
return null;
return std.fmt.parseInt(i64, stem, 10) catch null;
}
fn containsId(rows: []const sources_repo.SourceRow, id: i64) bool {
for (rows) |row| {
if (row.id == id) return true;
}
return false;
}
// ---------------------------------------------------------------------------
// tests
// ---------------------------------------------------------------------------
//
// Everything here runs against a `:memory:` database and touches no file. Real
// files, real HTTP and real swaps are the integration suite's (S9).
const testing = std.testing;
const migrations = @import("../storage/migrations.zig");
fn openMigrated() !db.Db {
var database = try db.Db.open(":memory:", .{ .mode = .memory });
errdefer database.close();
try db.applyPragmas(&database, .{});
_ = try migrations.migrate(&database);
return database;
}
fn testManager(database: *db.Db, fetcher_ptr: *fetcher.Fetcher) !Manager {
return Manager.init(
testing.allocator,
database,
// No test in this file reaches the filesystem: `acquire` answers before
// any directory is touched, and the header helpers are pure.
.{ .dir = std.Io.Dir.cwd() },
fetcher_ptr,
.{},
.{ .raw = .fromSeconds(30), .clock = .awake },
);
}
test "init leaves the manager with no snapshot and no statuses" {
var threaded: std.Io.Threaded = .init(testing.allocator, .{});
defer threaded.deinit();
const io = threaded.io();
var database = try openMigrated();
defer database.close();
var f: fetcher.Fetcher = undefined;
var manager = try testManager(&database, &f);
defer manager.deinit(io);
try testing.expectEqual(@as(u64, 0), manager.generation);
try testing.expectEqual(@as(usize, 0), manager.statuses.len);
try testing.expect(manager.current == null);
}
test "acquire before any reload returns null and holds no lock" {
var threaded: std.Io.Threaded = .init(testing.allocator, .{});
defer threaded.deinit();
const io = threaded.io();
var database = try openMigrated();
defer database.close();
var f: fetcher.Fetcher = undefined;
var manager = try testManager(&database, &f);
defer manager.deinit(io);
try testing.expect(manager.acquire(io) == null);
// A retained shared lock would make this exclusive lock block forever.
try testing.expect(manager.lock.tryLock(io));
manager.lock.unlock(io);
}
test "the disk gate skips a scheduled refresh only while writes are critical" {
var threaded: std.Io.Threaded = .init(testing.allocator, .{});
defer threaded.deinit();
const io = threaded.io();
var database = try openMigrated();
defer database.close();
var f: fetcher.Fetcher = undefined;
var manager = try testManager(&database, &f);
defer manager.deinit(io);
// No monitor: every pass runs, which is what the tests and `check` rely on.
try testing.expect(!manager.refreshGated());
try testing.expectEqual(@as(u64, 0), manager.refreshesGated());
var monitor: disk_monitor.Monitor = .init(.{}, std.Io.Dir.cwd(), ".", null);
manager.monitor = &monitor;
// `.ok` and `.warn` both allow writes: only `critical` stops them.
try testing.expect(!manager.refreshGated());
monitor.state_raw.store(@intFromEnum(disk_monitor.State.warn), .monotonic);
try testing.expect(!manager.refreshGated());
try testing.expectEqual(@as(u64, 0), manager.refreshesGated());
monitor.state_raw.store(@intFromEnum(disk_monitor.State.critical), .monotonic);
try testing.expect(manager.refreshGated());
try testing.expect(manager.refreshGated());
try testing.expectEqual(@as(u64, 2), manager.refreshesGated());
// Free space recovers and the schedule resumes; the counter keeps its total.
monitor.state_raw.store(@intFromEnum(disk_monitor.State.ok), .monotonic);
try testing.expect(!manager.refreshGated());
try testing.expectEqual(@as(u64, 2), manager.refreshesGated());
}
test "statusSnapshot on an empty manager copies nothing" {
var threaded: std.Io.Threaded = .init(testing.allocator, .{});
defer threaded.deinit();
const io = threaded.io();
var database = try openMigrated();
defer database.close();
var f: fetcher.Fetcher = undefined;
var manager = try testManager(&database, &f);
defer manager.deinit(io);
var out: [4]SourceStatus = undefined;
try testing.expectEqual(@as(usize, 0), manager.statusSnapshot(io, &out));
}
test "the header writer produces the documented text" {
var buf: [512]u8 = undefined;
var w: std.Io.Writer = .fixed(&buf);
const header: Header = .{
.url = "https://lists.example/hosts.txt",
.format = .hosts,
.fetched_at = 1_700_000_000,
.counts = .{
.domains = 12,
.wildcards = 3,
.skipped_regex = 2,
.skipped_unsupported = 1,
.invalid = 5,
.long_lines = 9,
.duplicates = 4,
},
.checksum = "0" ** 64,
};
try header.write(&w);
try testing.expectEqualStrings(
\\# nxdns blocklist
\\# url https://lists.example/hosts.txt
\\# format hosts
\\# fetched_at 1700000000
\\# domains 12
\\# wildcards 3
\\# skipped_regex 2
\\# skipped_unsupported 1
\\# invalid 5
\\
++ "# sha256 " ++ "0" ** 64 ++ "\n", w.buffered());
}
test "stripHeader returns the body of a compiled file" {
const file =
"# nxdns blocklist\n" ++
"# url https://lists.example/hosts.txt\n" ++
"ads.example.com\ntracker.example.net\n";
try testing.expectEqualStrings("ads.example.com\ntracker.example.net\n", stripHeader(file));
}
test "stripHeader returns everything for a file with no header" {
try testing.expectEqualStrings("a.example.com\n", stripHeader("a.example.com\n"));
}
test "stripHeader returns an empty body for a header-only file" {
try testing.expectEqualStrings("", stripHeader("# nxdns blocklist\n# sha256 x\n"));
}
test "stripHeader tolerates an unterminated header line" {
try testing.expectEqualStrings("", stripHeader("# nxdns blocklist"));
}
test "SourceStatus truncates a long error at max_error_len" {
var status: SourceStatus = .{ .id = 1 };
const long = "E" ** (max_error_len + 40);
status.fail(.fetch_failed, long);
try testing.expectEqual(State.fetch_failed, status.state);
try testing.expectEqual(@as(u8, max_error_len), status.last_error_len);
try testing.expectEqualStrings("E" ** max_error_len, status.errorText());
}
test "a success clears the recorded error" {
var status: SourceStatus = .{ .id = 7 };
status.fail(.compile_failed, "TooManyDomains");
status.succeed(1_700_000_000, .{ .domains = 3, .wildcards = 1 });
try testing.expectEqual(State.ok, status.state);
try testing.expectEqual(@as(i64, 1_700_000_000), status.last_success);
try testing.expectEqual(@as(u32, 3), status.counts.domains);
try testing.expectEqualStrings("", status.errorText());
}
test "compiledName spells the four file names of a source" {
var buf: [name_buf_len]u8 = undefined;
try testing.expectEqualStrings("42.list", compiledName(&buf, 42, ".list"));
try testing.expectEqualStrings("42.wild", compiledName(&buf, 42, ".wild"));
try testing.expectEqualStrings("42.raw.tmp", compiledName(&buf, 42, ".raw.tmp"));
try testing.expectEqualStrings("42.list.tmp", compiledName(&buf, 42, ".list.tmp"));
}
test "compiledId matches compiled files and nothing else" {
try testing.expectEqual(@as(?i64, 7), compiledId("7.list"));
try testing.expectEqual(@as(?i64, 7), compiledId("7.wild"));
try testing.expectEqual(@as(?i64, null), compiledId("7.list.tmp"));
try testing.expectEqual(@as(?i64, null), compiledId("7.raw.tmp"));
try testing.expectEqual(@as(?i64, null), compiledId("notes.list"));
try testing.expectEqual(@as(?i64, null), compiledId("README"));
}
test "a failed refresh keeps the fields of the compiled files still serving" {
var status: SourceStatus = .{ .id = 3 };
status.succeed(1_700_000_000, .{ .domains = 5, .wildcards = 2 });
// What `refreshSourceLocked` starts from, and what a download failure does
// to it.
var next = status;
next.last_attempt = 1_700_003_600;
next.fail(.fetch_failed, "Timeout");
try testing.expectEqual(State.fetch_failed, next.state);
try testing.expectEqualStrings("Timeout", next.errorText());
try testing.expectEqual(@as(i64, 1_700_000_000), next.last_success);
try testing.expectEqual(@as(i64, 1_700_003_600), next.last_attempt);
try testing.expectEqual(@as(u32, 5), next.counts.domains);
try testing.expectEqual(@as(u32, 2), next.counts.wildcards);
}
test "a load outcome never overwrites a refresh failure" {
try testing.expect(State.fetch_failed.isRefreshFailure());
try testing.expect(State.compile_failed.isRefreshFailure());
try testing.expect(State.no_valid_entries.isRefreshFailure());
// The three a load produces. `applyLoadOutcomes` may write over these,
// because nothing more informative is there.
try testing.expect(!State.ok.isRefreshFailure());
try testing.expect(!State.never_fetched.isRefreshFailure());
try testing.expect(!State.load_failed.isRefreshFailure());
}
fn testRow(id: i64, enabled: bool) sources_repo.SourceRow {
return .{
.id = id,
.url = "https://lists.example/hosts.txt",
.name = "example",
.enabled = enabled,
.last_updated = 1_700_000_000,
.domain_count = 9,
.wildcard_count = 4,
.skipped_regex_count = 1,
.checksum = "0" ** 64,
};
}
test "a candidate table carries prior entries over and leaves the published one alone" {
var published = [_]SourceStatus{ .{ .id = 1 }, .{ .id = 2 } };
published[0].setUrl("https://lists.example/one.txt");
published[0].fail(.fetch_failed, "HttpStatus");
published[0].loaded = true;
published[1].setUrl("https://lists.example/two.txt");
published[1].succeed(1_700_000_000, .{ .domains = 4 });
// Source 2 was deleted and source 3 added; source 1 kept its id and got a
// new url.
const rows = [_]sources_repo.SourceRow{
blk: {
var row = testRow(1, true);
row.url = "https://lists.example/moved.txt";
break :blk row;
},
testRow(3, true),
};
var candidate: [2]SourceStatus = undefined;
mergeStatuses(&candidate, &rows, &published);
try testing.expectEqual(@as(i64, 1), candidate[0].id);
try testing.expectEqual(State.fetch_failed, candidate[0].state);
try testing.expectEqualStrings("HttpStatus", candidate[0].errorText());
try testing.expect(candidate[0].loaded);
try testing.expectEqualStrings("https://lists.example/moved.txt", candidate[0].urlText());
try testing.expectEqual(@as(i64, 3), candidate[1].id);
try testing.expectEqual(State.never_fetched, candidate[1].state);
try testing.expect(!candidate[1].loaded);
// The published table is untouched, so a reload that fails before the swap
// leaves it describing the snapshot that is still serving — including the
// entry of the deleted source, which that snapshot still enforces.
try testing.expectEqual(@as(usize, 2), published.len);
try testing.expectEqual(@as(i64, 2), published[1].id);
try testing.expectEqual(State.ok, published[1].state);
try testing.expectEqualStrings("https://lists.example/one.txt", published[0].urlText());
}
test "a disabled source stops being loaded" {
var statuses = [_]SourceStatus{.{ .id = 1 }};
statuses[0].succeed(1_700_000_000, .{ .domains = 9 });
statuses[0].loaded = true;
const rows = [_]sources_repo.SourceRow{testRow(1, false)};
applyLoadOutcomes(&statuses, &rows, &.{.disabled});
// Nothing enforces it any more, and the state that described the files it
// used to serve is left as the record of how it last stood.
try testing.expect(!statuses[0].loaded);
try testing.expectEqual(State.ok, statuses[0].state);
}
test "a source that failed to refresh keeps its failure while its old files serve" {
// What `refreshSourceLocked` records, then what the `reload` that follows
// it in `refreshAll` finds: the previous files still load.
var statuses = [_]SourceStatus{.{ .id = 1 }};
statuses[0].succeed(1_700_000_000, .{ .domains = 9 });
statuses[0].fail(.fetch_failed, "HttpStatus");
const rows = [_]sources_repo.SourceRow{testRow(1, true)};
const body: matcher.Snapshot.Compiled = .{ .list_body = "", .wild_body = "" };
applyLoadOutcomes(&statuses, &rows, &.{.{ .loaded = body }});
try testing.expect(statuses[0].loaded);
try testing.expectEqual(State.fetch_failed, statuses[0].state);
try testing.expectEqualStrings("HttpStatus", statuses[0].errorText());
try testing.expectEqual(@as(u32, 9), statuses[0].counts.domains);
}
test "a load failure is recorded when no refresh failure explains it" {
var statuses = [_]SourceStatus{ .{ .id = 1 }, .{ .id = 2 } };
statuses[0].succeed(1_700_000_000, .{ .domains = 9 });
statuses[0].loaded = true;
statuses[1].fail(.compile_failed, "TooManyDomains");
statuses[1].loaded = true;
const rows = [_]sources_repo.SourceRow{ testRow(1, true), testRow(2, true) };
const reason: LoadOutcome = .{ .failed = .{ .state = .load_failed, .text = "ChecksumMismatch" } };
applyLoadOutcomes(&statuses, &rows, &.{ reason, reason });
try testing.expect(!statuses[0].loaded);
try testing.expectEqual(State.load_failed, statuses[0].state);
try testing.expectEqualStrings("ChecksumMismatch", statuses[0].errorText());
// The compile failure is why the files are unusable; it outranks the
// symptom the loader saw.
try testing.expect(!statuses[1].loaded);
try testing.expectEqual(State.compile_failed, statuses[1].state);
try testing.expectEqualStrings("TooManyDomains", statuses[1].errorText());
}
test "a load of a source this process never refreshed takes the row counters" {
var statuses = [_]SourceStatus{.{ .id = 1 }};
const rows = [_]sources_repo.SourceRow{testRow(1, true)};
const body: matcher.Snapshot.Compiled = .{ .list_body = "", .wild_body = "" };
applyLoadOutcomes(&statuses, &rows, &.{.{ .loaded = body }});
try testing.expect(statuses[0].loaded);
try testing.expectEqual(State.ok, statuses[0].state);
try testing.expectEqual(@as(i64, 1_700_000_000), statuses[0].last_success);
try testing.expectEqual(@as(u32, 9), statuses[0].counts.domains);
try testing.expectEqual(@as(u32, 4), statuses[0].counts.wildcards);
try testing.expectEqual(@as(u32, 1), statuses[0].counts.skipped_regex);
}
test "a status borrows nothing, so a copy outlives the table it came from" {
var status: SourceStatus = .{ .id = 5 };
status.setUrl("https://lists.example/hosts.txt");
status.fail(.load_failed, "ChecksumMismatch");
const copy = status;
// The source of the original is overwritten, as a reload overwrites the
// table: a copy that borrowed would read the new bytes or freed memory.
status.setUrl("https://other.example/other.txt");
status.fail(.fetch_failed, "Timeout");
try testing.expectEqualStrings("https://lists.example/hosts.txt", copy.urlText());
try testing.expectEqualStrings("ChecksumMismatch", copy.errorText());
try testing.expectEqual(State.load_failed, copy.state);
}
test "SourceStatus truncates a long url at max_url_len" {
var status: SourceStatus = .{ .id = 6 };
status.setUrl("https://lists.example/" ++ "p" ** max_url_len);
try testing.expectEqual(@as(u8, max_url_len), status.url_len);
try testing.expectEqualStrings(
("https://lists.example/" ++ "p" ** max_url_len)[0..max_url_len],
status.urlText(),
);
// A shorter url must not leave the tail of the longer one behind it.
status.setUrl("https://a.example/x");
try testing.expectEqualStrings("https://a.example/x", status.urlText());
}
test "compiledBodiesMatch verifies the bodies, not the presence of the files" {
const list_body = "a.example.com\nb.example.com\n";
const wild_body = "c.example.com\n";
const expected = bodyChecksum(list_body, wild_body);
const header =
"# nxdns blocklist\n" ++
"# url https://lists.example/hosts.txt\n";
try testing.expect(compiledBodiesMatch(header ++ list_body, header ++ wild_body, &expected));
// The corruption a reload reports as `ChecksumMismatch`: the file is there,
// its body is not what the checksum was taken over.
try testing.expect(!compiledBodiesMatch(header ++ "a.example.com\nb.exa", header ++ wild_body, &expected));
try testing.expect(!compiledBodiesMatch("", "", &expected));
}
test "rejectedWithoutEntries fails a compile that produced nothing usable" {
// An html error page: every line is rejected, nothing is written.
try testing.expect(rejectedWithoutEntries(.{ .invalid = 12, .skipped_unsupported = 3 }));
// A compressed body: one long binary run with no newline in it.
try testing.expect(rejectedWithoutEntries(.{ .long_lines = 1 }));
// An empty list rejects nothing and is legal.
try testing.expect(!rejectedWithoutEntries(.{}));
// A real list rejects lines and still produces entries.
try testing.expect(!rejectedWithoutEntries(.{ .domains = 1000, .invalid = 40 }));
try testing.expect(!rejectedWithoutEntries(.{ .wildcards = 7, .skipped_unsupported = 90 }));
}
fn sampleOf(input: []const u8, out: []u8) ![]const u8 {
var r: std.Io.Reader = .fixed(input);
var w: std.Io.Writer = .fixed(out);
try collectSample(&r, &w);
return w.buffered();
}
test "collectSample skips comments instead of spending the sample on them" {
const gpa = testing.allocator;
const long_comment = "# " ++ "c" ** (compiler.max_line_len - 2) ++ "\n";
var input: std.ArrayList(u8) = .empty;
defer input.deinit(gpa);
// Sixteen of these fill a 64 KiB window on their own.
for (0..20) |_| try input.appendSlice(gpa, long_comment);
try input.appendSlice(gpa, "0.0.0.0 ads.example.com\n0.0.0.0 tracker.example.net\n");
const out = try gpa.alloc(u8, sample_buf_len);
defer gpa.free(out);
const sample = try sampleOf(input.items, out);
try testing.expectEqualStrings(
"0.0.0.0 ads.example.com\n0.0.0.0 tracker.example.net\n",
sample,
);
try testing.expectEqual(parsers.Format.hosts, parsers.detectFormat(sample));
}
test "collectSample stops at sample_lines counted lines" {
const gpa = testing.allocator;
var input: std.ArrayList(u8) = .empty;
defer input.deinit(gpa);
var line_buf: [64]u8 = undefined;
for (0..parsers.sample_lines + 10) |i| {
try input.appendSlice(gpa, try std.fmt.bufPrint(&line_buf, "0.0.0.0 host{d}.example.com\n", .{i}));
}
const out = try gpa.alloc(u8, sample_buf_len);
defer gpa.free(out);
const sample = try sampleOf(input.items, out);
var lines = std.mem.tokenizeScalar(u8, sample, '\n');
var count: usize = 0;
while (lines.next()) |_| count += 1;
try testing.expectEqual(parsers.sample_lines, count);
}
test "collectSample keeps the abp marker a long comment run would have hidden" {
const gpa = testing.allocator;
const long_comment = "! " ++ "c" ** (compiler.max_line_len - 2) ++ "\n";
var input: std.ArrayList(u8) = .empty;
defer input.deinit(gpa);
for (0..20) |_| try input.appendSlice(gpa, long_comment);
try input.appendSlice(gpa, "||ads.example.com^\n");
const out = try gpa.alloc(u8, sample_buf_len);
defer gpa.free(out);
const sample = try sampleOf(input.items, out);
try testing.expectEqualStrings("||ads.example.com^\n", sample);
try testing.expectEqual(parsers.Format.abp, parsers.detectFormat(sample));
}
test "collectSample skips a line over max_line_len" {
const gpa = testing.allocator;
var input: std.ArrayList(u8) = .empty;
defer input.deinit(gpa);
try input.appendNTimes(gpa, 'x', 8 * compiler.max_line_len);
try input.appendSlice(gpa, "\nads.example.com\n");
const out = try gpa.alloc(u8, sample_buf_len);
defer gpa.free(out);
// A `Reader.fixed` holds the whole input, so the over-long line comes back
// rather than being refused. The compiler would skip it, so the sniff does.
const sample = try sampleOf(input.items, out);
try testing.expectEqualStrings("ads.example.com\n", sample);
}
test "collectSample steps over a line that does not fit the reader buffer" {
const gpa = testing.allocator;
var input: std.ArrayList(u8) = .empty;
defer input.deinit(gpa);
try input.appendNTimes(gpa, 'x', 4 * compiler.max_line_len);
try input.appendSlice(gpa, "\nads.example.com\n");
// A reader buffer smaller than the long line makes `takeDelimiter` report
// `error.StreamTooLong` and leave the stream where it was, which is the
// path that loops forever without the discard.
var backing: std.Io.Reader = .fixed(input.items);
var reader_buf: [compiler.max_line_len]u8 = undefined;
var limited = backing.limited(.unlimited, &reader_buf);
const out = try gpa.alloc(u8, sample_buf_len);
defer gpa.free(out);
var w: std.Io.Writer = .fixed(out);
try collectSample(&limited.interface, &w);
try testing.expectEqualStrings("ads.example.com\n", w.buffered());
}
test "bodyChecksum covers the list body followed by the wild body" {
const both = bodyChecksum("a.example.com\n", "b.example.com\n");
var hasher = Sha256.init(.{});
hasher.update("a.example.com\nb.example.com\n");
var digest: [Sha256.digest_length]u8 = undefined;
hasher.final(&digest);
try testing.expectEqualStrings(&std.fmt.bytesToHex(digest, .lower), &both);
// Order matters: the two halves are not interchangeable.
try testing.expect(!std.mem.eql(u8, &both, &bodyChecksum("b.example.com\n", "a.example.com\n")));
}