Subject: Re: [PATCH] sha1_file: don't convert off_t to size_t too early to avoid potential die()

From: Junio C Hamano <[email-masked]>
Date: Mon, 22 Sep 2014 12:41:32 -0700

Steffen Prohaska <[email-masked]> writes:

> This patch should be applied on top of sp/stream-clean-filter.

... or it can be squashed in as a fix, as the topic is not yet in
'next'.

> index_stream() might internally also be able to handle large files to
> some extent.  But it uses size_t for its third argument, and we must
> already die() when calling it.  It might be a good idea to convert its
> interface to use off_t and push the size checks further down the stack.
> In general, it might be good idea to carefully consider whether to use
> off_t or size_t when passing file-related sizes around.  To me it looks
> like a separate issue for a separate patch series (I have no specific
> plans to prepare one).
>
>  sha1_file.c | 13 +++++++++----
>  1 file changed, 9 insertions(+), 4 deletions(-)
>
> diff --git a/sha1_file.c b/sha1_file.c
> index 5b0e67a..6f18c22 100644
> --- a/sha1_file.c
> +++ b/sha1_file.c
> @@ -3180,17 +3180,22 @@ int index_fd(unsigned char *sha1, int fd, struct stat *st,
>  	     enum object_type type, const char *path, unsigned flags)
>  {
>  	int ret;
> -	size_t size = xsize_t(st->st_size);
>  
> +	/*
> +	 * Call xsize_t() only when needed to avoid potentially unnecessary
> +	 * die() for large files.
> +	 */
>  	if (type == OBJ_BLOB && path && would_convert_to_git_filter_fd(path))
>  		ret = index_stream_convert_blob(sha1, fd, path, flags);
>  	else if (!S_ISREG(st->st_mode))
>  		ret = index_pipe(sha1, fd, type, path, flags);
> -	else if (size <= big_file_threshold || type != OBJ_BLOB ||
> +	else if (st->st_size <= big_file_threshold || type != OBJ_BLOB ||
>  		 (path && would_convert_to_git(path)))
> -		ret = index_core(sha1, fd, size, type, path, flags);
> +		ret = index_core(sha1, fd, xsize_t(st->st_size), type, path,
> +				 flags);
>  	else
> -		ret = index_stream(sha1, fd, size, type, path, flags);
> +		ret = index_stream(sha1, fd, xsize_t(st->st_size), type, path,
> +				   flags);
>  	close(fd);
>  	return ret;
>  }