RFR: 8229872: (fs) Increase buffer size used with getmntent

[Alan Bateman]

On 04/09/2019 13:07, Vladimir Kempik wrote:
> Hello
> Please review v5 of fix: 
> http://cr.openjdk.java.net/~vkempik/8229872/webrev.05
>
> diff vs v4:
> moved getlinelen and rewind in UnixNativeDispatcher.c right after fclose.
> changed getlinelen return type to jlong
> slightly improved the comment about getlinelen and updated comments 
> formatting in native part.
>
LinuxNativeDispatcher.getmntent shouldn't free buf before it has copied 
the strings from the mntent structure as it could potentially access 
memory that is allocated for something else. It also needs to check the 
return from malloc and throw an exception if possible (you'll see other 
examples of this).

The size returned by getline doesn't include the NUL terminator. Are you 
sure that this size is large enough for the buffer that you specify to 
getmntent_r to store the strings? I expect it is because the strings 
that are stuffed into the buffer are a subset of the items that on the 
entry. Do I have that right?

Have you considered using fseek instead of rewind to avoid the 
uncertainty as to whether errno is set?

-Alan