98705 - The Netscape 4 plugins do not work if the NPP_WriteReady returns values less the 16K

Status: VERIFIED FIXED

(Core Graveyard :: Plug-ins, defect, P2)

Description

[amardare]

From Bugzilla Helper:
User-Agent: Mozilla/4.0 (compatible; MSIE 5.5; Windows 98)
BuildID:    000000000

I was writing a plugin for mozilla and NPP_WriteReady needs to return 4k in my 
case. I looked in the file 
mozilla\modules\plugin\base\src\ns4xPluginInstance.cpp in the function 
OnDataAvailable. Mozilla reads a buffer of 16k of data and if NPP_WriteReady 
returns less than 16k, it needs to shift the data in the mStreamBuffer. Mozilla 
does this by calling
strncpy(mStreamBuffer,mStreamBuffer+writeCount,amountRead);
which is wrong because strncpy is not supposed to be used for overlapping 
memory.
I replaced that call with
memmove(mStreamBuffer,mStreamBuffer+writeCount,amountRead);
and the plugin plays well.
Can you please confirm/correct this problem?

Reproducible: Always
Steps to Reproduce:
1. Use a plugin that returns less than 16k as NPP_WriteReady
2.
3.

Comment 1

[av (gone)]

Reporter, thanks for pointing this out. Peter, looks like this is trivial fix in
what you did some time ago for NPP_WriteReady. Setting 0.9.5 for now but maybe
we should consider it for the branch.

Comment 2

[Peter Lubczynski]

Yeah, this seems pretty simple to do.

Is all what needs to be done is s/strncpy/memmove?

Comment 3

[Peter Lubczynski]

Attachment: patch to use memove

Comment 4

[av (gone)]

Seems right thing to do. r=av.

Comment 5

[Marc Attinasi]

Comment on attachment 48811 [details] [diff] [review]
patch to use memove

sr=attinasi

Comment 6

[Robert O'Callahan (:roc) (email my personal email if necessary)]

a=roc+moz for the 0.9.4 branch

Comment 7

[Peter Lubczynski]

Fix checked in to both trunk and branch, marking FIXED.

Comment 8

[shrirang khanzode]

v