Zoo: check for write permissions before updating a model

[lnotspotl]

Purpose

Without this check, the zoo manager tries to update a model, create a lock and in case of a protected path (such as /usr/lib) this leads to an insufficient permission error.

With this check in place, we do not try to update the model and simply return the already cached one or in the edge case of there being no cached model, we error out.

[moratom]

bugbot run

[cursor]

Bug: ZooManager Cache Locking and Validation Issues

The commit introduces a compilation error as getModelFromZoo attempts to access the private member ZooManager::cacheFolderLock. Additionally, when the cache directory lacks write permissions, the ZooManager cannot acquire a lock. In this state, if a model is cached, it is immediately returned. This behavior ignores the useCached parameter (returning cached models even when explicitly disallowed) and bypasses validation against the latest online version, potentially serving stale models even with internet connectivity.

src/modelzoo/Zoo.cpp#L595-L605

depthai-core/src/modelzoo/Zoo.cpp

Lines 595 to 605 in 1e21c18

	// Check if model is cached
	bool hasLock = (zooManager.cacheFolderLock != nullptr);
	bool modelIsCached = zooManager.isModelCached();
	// Return the model right away if lock is not held and model is cached
	if(!hasLock && modelIsCached) {
	fs::path modelPath = zooManager.loadModelFromCache();
	logger::info("Model is cached but model lock could not be acquired (likely due to insufficient write permissions). Using cached model located at {}",
	modelPath);
	return modelPath;
	}

Fix in Cursor • Fix in Web

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[moratom]

Thanks!

[moratom]

Intentionally removed?