[ccache] ccache doesn't notice gzip CRC errors

[Joel Rosdahl]

On 2010-10-29 03:54, Wilson Snyder wrote:
> GZIP files contain CRC checksums, however ccache doesn't
> notice CRC errors because it doesn't check gzerror at the
> end of decompression.  This patch fixes it.  (It's arguably
> a bad API decision on the gz library's part, but we're stuck
> with it.)

Thanks!

> --- a/util.c
> +++ b/util.c
> @@ -284,7 +284,12 @@ copy_file(const char *src, const char *dest, int compress_dest)
>  			goto error;
>  		}
>  	}
> -	if (n == 0 && !gzeof(gz_in)) {
> +
> +	/* gzeof won't tell if there's an error in the trailing crc,
> +	   so must gzeof then test gzerror before considering everything ok */
> +	gzeof(gz_in);

Why is the above gzeof call needed? The implementation doesn't seem to
modify the state and the documentation doesn't imply that it could.

> +	gzerror(gz_in, &errnum);
> +	if (!gzeof(gz_in) || (errnum != Z_OK && errnum != Z_STREAM_END)) {
>  		cc_log("gzread error: %s (errno: %s)",
>  		       gzerror(gz_in, &errnum), strerror(errno));
>  		gzclose(gz_in);

Looks good otherwise.

-- Joel