[libvirt] [PATCH] Fix virPipeReadUntilEOF on more than 1024 bytes of data

[Eric Blake]

On 11/02/2010 01:39 PM, Daniel Veillard wrote:
>   This is a bug I found while testing the smbios support, it uses
> virPipeReadUntilEOF to read the stdout of the exec'ed dmidecode
> process and this failed to capture the full output. It read only
> 1024 bytes.
>   The problem is that this is based on a poll loop, and in the
> loop we read at most 1024 bytes per filedescriptor, but we also
> note in the loop if poll indicates that the process won't output
> more than that on that fd by setting finished[i] = 1.
>   The simplest way is that if we read a full buffer make sure
> finished[i] is still 0 because we will need another pass in the
> loop.
> 
> Daniel
> 
> diff --git a/src/util/util.c b/src/util/util.c
> index f7c7d32..a059675 100644
> --- a/src/util/util.c
> +++ b/src/util/util.c
> @@ -984,6 +984,9 @@ virPipeReadUntilEOF(int outfd, int errfd,
>  
>              got = read(fds[i].fd, data, sizeof(data));
>  
> +            if (got == sizeof(data))
> +                finished[i] = 0;
> +

ACK.  Worst case is a file that is exactly a multiple of 1024 now
requiring one extra read to ascertain this fact, but that's not bad.

-- 
Eric Blake   eblake at redhat.com    +1-801-349-2682
Libvirt virtualization library http://libvirt.org

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