feat(3p/nix): add --trace-file-access to nix-instantiate

This builds on edef's work with depot-scan by adding a dedicated
flag to the command. We piggyback on upstream's restricted-mode
implementation, the checkSourcePath function.

Change-Id: I52bb613549f40dbca1e8caa036635910c1a3d6d0
Reviewed-on: https://cl.tvl.fyi/c/depot/+/1654
Tested-by: BuildkiteCI
Reviewed-by: glittershark <grfn@gws.fyi>
This commit is contained in:
Kane York 2020-08-04 19:12:49 -07:00 committed by kanepyork
parent 6a128fc162
commit 68b5306c56
4 changed files with 49 additions and 0 deletions

View file

@ -39,6 +39,7 @@
</arg>
<arg><option>--add-root</option> <replaceable>path</replaceable></arg>
<arg><option>--indirect</option></arg>
<arg><option>--<arg>no</arg>trace-file-access</option></arg>
<group>
<arg choice='plain'><option>--expr</option></arg>
<arg choice='plain'><option>-E</option></arg>
@ -131,6 +132,13 @@ input.</para>
</varlistentry>
<varlistentry><term><option>--<arg>no</arg>trace-file-access</option></term>
<listitem><para>While instantiating the expression, the evaluator will
print the full path to any files it reads with the prefix
<envar>trace-file-access: </envar> to the standard error.</para>
</listitem>
</varlistentry>
<varlistentry><term><option>--json</option></term>
<listitem><para>When used with <option>--eval</option>, print the resulting
@ -253,6 +261,10 @@ $ nix-instantiate --eval --xml --strict -E 'rec { x = "foo"; y = x; }'
</refsection>
<refsection><title>Conformance</title>
<para>The <option>--trace-file-access</option> option is a nonstandard
extension added by Tvix in 2020.</para>
</refsection>
<refsection condition="manpage"><title>Environment variables</title>

View file

@ -379,6 +379,7 @@ EvalState::EvalState(const Strings& _searchPath, const ref<Store>& store)
EvalState::~EvalState() = default;
Path EvalState::checkSourcePath(const Path& path_) {
TraceFileAccess(path_);
if (!allowedPaths) {
return path_;
}
@ -1819,6 +1820,20 @@ void EvalState::printStats() {
}
}
void EvalState::TraceFileAccess(const Path& realPath) {
if (file_access_trace_fn.has_value()) {
if (last_traced_file != realPath) {
(*file_access_trace_fn)(realPath);
// Basic deduplication.
last_traced_file = std::string(realPath);
}
}
}
void EvalState::EnableFileAccessTracing(std::function<void(const Path&)> fn) {
file_access_trace_fn = fn;
}
size_t valueSize(const Value& v) {
traceable_flat_hash_set<const Bindings*> seenBindings;
traceable_flat_hash_set<const Env*> seenEnvs;

View file

@ -284,6 +284,10 @@ class EvalState : public gc {
void realiseContext(const PathSet& context);
/* File access tracing. */
void TraceFileAccess(const Path& path);
void EnableFileAccessTracing(std::function<void(const Path&)> fn);
private:
unsigned long nrEnvs = 0;
unsigned long nrValuesInEnvs = 0;
@ -299,6 +303,10 @@ class EvalState : public gc {
bool countCalls;
std::optional<std::function<void(const Path&)>> file_access_trace_fn =
std::nullopt;
Path last_traced_file = "";
typedef std::map<Symbol, size_t> PrimOpCalls;
PrimOpCalls primOpCalls;

View file

@ -96,6 +96,7 @@ static int _main(int argc, char** argv) {
bool findFile = false;
bool evalOnly = false;
bool parseOnly = false;
bool traceFileAccess = false;
OutputKind outputKind = okPlain;
bool xmlOutputSourceLocation = true;
bool strict = false;
@ -143,6 +144,14 @@ static int _main(int argc, char** argv) {
repair = Repair;
} else if (*arg == "--dry-run") {
settings.readOnlyMode = true;
} else if (*arg == "--trace-file-access") {
traceFileAccess = true;
} else if (*arg == "--trace-file-access=true") {
traceFileAccess = true;
} else if (*arg == "--trace-file-access=false") {
traceFileAccess = false;
} else if (*arg == "--notrace-file-access") {
traceFileAccess = false;
} else if (*arg != "" && arg->at(0) == '-') {
return false;
} else {
@ -161,6 +170,11 @@ static int _main(int argc, char** argv) {
auto state = std::make_unique<EvalState>(myArgs.searchPath, store);
state->repair = repair;
if (traceFileAccess) {
state->EnableFileAccessTracing([](const Path& path) {
std::cerr << "trace: depot-scan: " << path << "\n";
});
}
Bindings& autoArgs = *myArgs.getAutoArgs(*state);