[Rd] Crashing R with readline()
murdoch.duncan at gmail.com
Thu Dec 29 23:50:36 CET 2011
On 11-12-29 4:37 PM, Duncan Murdoch wrote:
> On 11-12-29 9:49 AM, Henrik Bengtsson wrote:
>> I get the following with R v2.14.1 patched on Windows 7:
>> % Rterm --vanilla --silent
>> R version 2.14.1 Patched (2011-12-26 r58001)
>> Platform: x86_64-pc-mingw32/x64 (64-bit)
>>  LC_COLLATE=English_United States.1252
>>  LC_CTYPE=English_United States.1252
>>  LC_MONETARY=English_United States.1252
>>  LC_NUMERIC=C
>>  LC_TIME=English_United States.1252
>> attached base packages:
>>  stats graphics grDevices utils datasets methods base
>>> readline(sprintf("%-*s:", 180, "A prompt"))
>> A prompt
>>  ""
>> Error: caught access violation - continue with care
>> It is a consistent behavior.
> I can reproduce this, but I can't spot where the problem is. I/O in
> Rterm is very complicated, because we use a getline library that
> implements line editing, and we run the I/O in a thread so that graphics
> windows can be updated while waiting for input.
> Presumably the problem is the long prompt causing a buffer overflow
> somewhere, and a workaround is to use a more reasonable length of
> prompt, but I don't think I'm going to be able to offer a real fix. I'd
> guess this bug is local to Rterm in Windows, but we don't really have
> good tools there to detect buffer overflows.
Just had another idea, and found the problem - a buffer overflow in
getline. I'll fix it.
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