On Wed, 7 Nov 2018 14:43:55 -0800, Stanislav Fomichev wrote:
> bpftool will use bpf_object__pin in the next commit to pin all programs
> and maps from the file; in case of a partial failure, we need to get
> back to the clean state (undo previous program/map pins).
>
> Signed-off-by: Stanislav Fomichev <s...@google.com>
> ---
> tools/lib/bpf/libbpf.c | 58 ++++++++++++++++++++++++++++++++++--------
> 1 file changed, 48 insertions(+), 10 deletions(-)
>
> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> index d6e62e90e8d4..309abe7196f3 100644
> --- a/tools/lib/bpf/libbpf.c
> +++ b/tools/lib/bpf/libbpf.c
> @@ -1803,14 +1803,17 @@ int bpf_object__pin(struct bpf_object *obj, const
> char *path)
>
> len = snprintf(buf, PATH_MAX, "%s/%s", path,
> bpf_map__name(map));
> - if (len < 0)
> - return -EINVAL;
> - else if (len >= PATH_MAX)
> - return -ENAMETOOLONG;
> + if (len < 0) {
> + err = -EINVAL;
> + goto err_unpin_maps;
> + } else if (len >= PATH_MAX) {
> + err = -ENAMETOOLONG;
> + goto err_unpin_maps;
> + }
>
> err = bpf_map__pin(map, buf);
> if (err)
> - return err;
> + goto err_unpin_maps;
> }
>
> bpf_object__for_each_program(prog, obj) {
> @@ -1819,17 +1822,52 @@ int bpf_object__pin(struct bpf_object *obj, const
> char *path)
>
> len = snprintf(buf, PATH_MAX, "%s/%s", path,
> prog->section_name);
> - if (len < 0)
> - return -EINVAL;
> - else if (len >= PATH_MAX)
> - return -ENAMETOOLONG;
> + if (len < 0) {
> + err = -EINVAL;
> + goto err_unpin_programs;
> + } else if (len >= PATH_MAX) {
> + err = -ENAMETOOLONG;
> + goto err_unpin_programs;
> + }
>
> err = bpf_program__pin(prog, buf);
> if (err)
> - return err;
> + goto err_unpin_programs;
> }
>
> return 0;
> +
> +err_unpin_programs:
> + bpf_object__for_each_program(prog, obj) {
> + char buf[PATH_MAX];
> + int len;
> +
> + len = snprintf(buf, PATH_MAX, "%s/%s", path,
> + prog->section_name);
> + if (len < 0)
> + continue;
> + else if (len >= PATH_MAX)
> + continue;
> +
> + unlink(buf);
I think that's no bueno, if pin failed because the file already exists
you'll now remove that already existing file.
> + }
> +
> +err_unpin_maps:
> + bpf_map__for_each(map, obj) {
> + char buf[PATH_MAX];
> + int len;
> +
> + len = snprintf(buf, PATH_MAX, "%s/%s", path,
> + bpf_map__name(map));
> + if (len < 0)
> + continue;
> + else if (len >= PATH_MAX)
> + continue;
> +
> + unlink(buf);
> + }
> +
> + return err;
> }
>
> void bpf_object__close(struct bpf_object *obj)
