Re: [PATCH 22/48] perf tools: Add perf_data_file__switch() helper

[Jiri Olsa]

On Mon, Feb 22, 2016 at 09:10:49AM +0000, Wang Nan wrote:
> perf_data_file__switch() closes current output file, renames it, then
> open a new one to continue record. It will be used by perf record
> to split output into multiple perf.data files.
> 
> Signed-off-by: Wang Nan <wangnan0@xxxxxxxxxx>
> Signed-off-by: He Kuang <hekuang@xxxxxxxxxx>
> Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
> Cc: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
> Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
> Cc: Zefan Li <lizefan@xxxxxxxxxx>
> Cc: pi3orama@xxxxxxx
> ---
>  tools/perf/util/data.c | 36 ++++++++++++++++++++++++++++++++++++
>  tools/perf/util/data.h | 11 ++++++++++-
>  2 files changed, 46 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/perf/util/data.c b/tools/perf/util/data.c
> index 1921942..bfded6a 100644
> --- a/tools/perf/util/data.c
> +++ b/tools/perf/util/data.c
> @@ -136,3 +136,39 @@ ssize_t perf_data_file__write(struct perf_data_file *file,
>  {
>  	return writen(file->fd, buf, size);
>  }
> +
> +int perf_data_file__switch(struct perf_data_file *file,
> +			   const char *postfix,
> +			   size_t pos, bool at_exit)
> +{
> +	char *new_filepath;
> +	int ret;
> +
> +	if (check_pipe(file))
> +		return -EINVAL;
> +	if (perf_data_file__is_read(file))
> +		return -EINVAL;
> +
> +	if (asprintf(&new_filepath, "%s.%s", file->path, postfix) < 0)
> +		return -ENOMEM;
> +
> +	rename(file->path, new_filepath);

should we check for rename's return value?

jirka