- Last modified: June 6, 2011
- Authors: Sandeep Akula (Adobe Systems), Vinod Menon (Adobe Systems)
- Contributors: Josh Aas (Mozilla Corporation)
Currently there are no mechanisms available for browser plug-ins to add plug-in specific data into browser-generated crash reports. Additional information added by browser plug-ins will facilitate easier and faster troubleshooting of plug-ins. This necessitates browsers to provide interfaces through which plug-in can indicate to the browser, plug-in specific data that it needs browser to capture as part of crash dumps in case a crash occurs. The NPAPI doesn’t have any interfaces to send plug-in’s custom data along with crash dump when an unhandled exception occurs in the plug-in. To support this we are proposing an extension to the current API.
Two new functions for registering and unregistering blocks of memory are added.
NPError NPN_ErrorReportingRegisterMemoryBlock(const char* key, uint32_t flags, void* pMemBlock, size_t sizeOfMemBlock);
key: unique string identifying the memory block
- Future use, no flags defined now.
pMemBlock: The starting address of the memory block.
sizeOfMemBlock: The size of the memory block in bytes
NPERR_OUT_OF_MEMORY_ERROR: If the memory size exceeds the maximum size allowed
NPERR_INVALID_PARAM: If the registration fails
NPERR_NO_ERROR: If successful
Registered buffers must contain textual UTF8/ASCII data which is
NULL terminated. Non-textual data can be encoded as text before it is placed in a registered buffer.
The browser will not read a registered buffer upon registration, thus there is no need to re-register after changing the contents of a registered buffer. The buffer will only be read from a crash handler. Registering memory address
NULL (zero) will not be allowed, to avoid the issue in which a plugin might register the result of a
malloc call without a
If the API is called with a key that has already been registered, the new registration will replace the old one. Plugins can attempt to register multiple buffers.
NPN_GetValue with new key
NPNVmaxCrashMemoryBlockSize can be used to get the maximum amount of memory available for a plugin's block registration. This is not a per-block or per-instance limit, it is a per-plugin limit.
NPError NPN_ErrorReportingUnregisterMemoryBlock(const char* key);
key: key value which was used to register the memory block
NPERR_INVALID_PARAM: invalid memory key
NPERR_GENERIC_ERROR: any generic error
NPERR_NO_ERROR: memory successfully unregistered
- We need to check with browser vendor crash reporting teams to make sure we can handle arbitrary blocks of memory. Right now, for example, I think Mozilla is only set up to handle string annotations and I'm not sure what additional challenges random memory will pose.