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Limit length of message sent to DS SendError call (#1618)

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If total length is over 65536, the packet will get thrown out.
This can be a problem in stack overflow cases (e.g. infinite recursion).
This commit is contained in:
Thad House
2019-03-03 15:43:04 -08:00
committed by Peter Johnson
parent a095ec2d8f
commit 655763a9a7
1 changed files with 37 additions and 2 deletions
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39
hal/src/main/native/athena/FRCDriverStation.cpp
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@@ -292,8 +292,43 @@ int32_t HAL_SendError(HAL_Bool isError, int32_t errorCode, HAL_Bool isLVCode,
}
int retval = 0;
if (i == KEEP_MSGS || (curTime - prevMsgTime[i]) >= std::chrono::seconds(1)) {
retval = FRC_NetworkCommunication_sendError(isError, errorCode, isLVCode,
details, location, callStack);
wpi::StringRef detailsRef{details};
wpi::StringRef locationRef{location};
wpi::StringRef callStackRef{callStack};
// 1 tag, 4 timestamp, 2 seqnum
// 2 numOccur, 4 error code, 1 flags, 6 strlen
// 1 extra needed for padding on Netcomm end.
size_t baseLength = 21;
if (baseLength + detailsRef.size() + locationRef.size() +
callStackRef.size() <=
65536) {
// Pass through
retval = FRC_NetworkCommunication_sendError(isError, errorCode, isLVCode,
details, location, callStack);
} else if (baseLength + detailsRef.size() > 65536) {
// Details too long, cut both location and stack
auto newLen = 65536 - baseLength;
std::string newDetails{details, newLen};
char empty = '\0';
retval = FRC_NetworkCommunication_sendError(
isError, errorCode, isLVCode, newDetails.c_str(), &empty, &empty);
} else if (baseLength + detailsRef.size() + locationRef.size() > 65536) {
// Location too long, cut stack
auto newLen = 65536 - baseLength - detailsRef.size();
std::string newLocation{location, newLen};
char empty = '\0';
retval = FRC_NetworkCommunication_sendError(
isError, errorCode, isLVCode, details, newLocation.c_str(), &empty);
} else {
// Stack too long
auto newLen = 65536 - baseLength - detailsRef.size() - locationRef.size();
std::string newCallStack{callStack, newLen};
retval = FRC_NetworkCommunication_sendError(isError, errorCode, isLVCode,
details, location,
newCallStack.c_str());
}
if (printMsg) {
if (location && location[0] != '\0') {
wpi::errs() << (isError ? "Error" : "Warning") << " at " << location