libutil: handle json builder log messages with unexpected format

Before this change, expressions like:

with import <nixpkgs> {};
runCommand "foo" {} ''
  echo '@nix {}' >&$NIX_LOG_FD
''

would result in Lix crashing, because accessing nonexistent fields of
a JSON object throws an exception.

Rather than handling each field individually, we just catch JSON
exceptions wholesale. Since these log messages are an unusual
circumstance, log a warning when this happens.

Fixes #544.

Change-Id: Idc2d8acf6e37046b3ec212f42e29269163dca893
This commit is contained in:
Linus Heckemann 2024-10-11 17:16:32 +02:00
parent f6077314fa
commit e55cd3beea
2 changed files with 50 additions and 29 deletions

View file

@ -305,37 +305,45 @@ bool handleJSONLogMessage(nlohmann::json & json,
const Activity & act, std::map<ActivityId, Activity> & activities,
bool trusted)
{
std::string action = json["action"];
try {
std::string action = json["action"];
if (action == "start") {
auto type = (ActivityType) json["type"];
if (trusted || type == actFileTransfer)
activities.emplace(std::piecewise_construct,
std::forward_as_tuple(json["id"]),
std::forward_as_tuple(*logger, (Verbosity) json["level"], type,
json["text"], getFields(json["fields"]), act.id));
if (action == "start") {
auto type = (ActivityType) json["type"];
if (trusted || type == actFileTransfer)
activities.emplace(std::piecewise_construct,
std::forward_as_tuple(json["id"]),
std::forward_as_tuple(*logger, (Verbosity) json["level"], type,
json["text"], getFields(json["fields"]), act.id));
}
else if (action == "stop")
activities.erase((ActivityId) json["id"]);
else if (action == "result") {
auto i = activities.find((ActivityId) json["id"]);
if (i != activities.end())
i->second.result((ResultType) json["type"], getFields(json["fields"]));
}
else if (action == "setPhase") {
std::string phase = json["phase"];
act.result(resSetPhase, phase);
}
else if (action == "msg") {
std::string msg = json["msg"];
logger->log((Verbosity) json["level"], msg);
}
return true;
} catch (nlohmann::json::exception &e) {
warn(
"warning: Unable to handle a JSON message from the builder: %s",
e.what()
);
return false;
}
else if (action == "stop")
activities.erase((ActivityId) json["id"]);
else if (action == "result") {
auto i = activities.find((ActivityId) json["id"]);
if (i != activities.end())
i->second.result((ResultType) json["type"], getFields(json["fields"]));
}
else if (action == "setPhase") {
std::string phase = json["phase"];
act.result(resSetPhase, phase);
}
else if (action == "msg") {
std::string msg = json["msg"];
logger->log((Verbosity) json["level"], msg);
}
return true;
}
bool handleJSONLogMessage(const std::string & msg,

View file

@ -31,6 +31,18 @@ let
outputHashAlgo = "sha256";
outputHash = "1dq9p0hnm1y75q2x40fws5887bq1r840hzdxak0a9djbwvx0b16d";
};
unusual-logging = mkDerivation {
name = "unusual-logging";
buildCommand = ''
{
echo "@nix 1"
echo "@nix {}"
echo '@nix {"action": null}'
} >&$NIX_LOG_FD
touch $out
'';
};
in
mkDerivation {
name = "dependencies-top";
@ -40,6 +52,7 @@ mkDerivation {
input1_drv = input1;
input2_drv = input2;
input0_drv = input0;
unusual_logging_drv = unusual-logging;
fod_input_drv = fod_input;
meta.description = "Random test package";
}