Re: [PATCH v2 2/9] libbpf: Introduce bpf_obj_get_flags()

[Andrii Nakryiko]

On Thu, Jun 2, 2022 at 7:38 AM Roberto Sassu <roberto.sassu@xxxxxxxxxx> wrote:
>
> Introduce the bpf_obj_get_flags() function, so that it is possible to
> specify the needed permissions for obtaining a file descriptor from a
> pinned object.
>
> Signed-off-by: Roberto Sassu <roberto.sassu@xxxxxxxxxx>
> ---
>  tools/lib/bpf/bpf.c      | 8 +++++++-
>  tools/lib/bpf/bpf.h      | 1 +
>  tools/lib/bpf/libbpf.map | 1 +
>  3 files changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
> index 33bac2006043..a5fc40f6ce13 100644
> --- a/tools/lib/bpf/bpf.c
> +++ b/tools/lib/bpf/bpf.c
> @@ -670,18 +670,24 @@ int bpf_obj_pin(int fd, const char *pathname)
>         return libbpf_err_errno(ret);
>  }
>
> -int bpf_obj_get(const char *pathname)
> +int bpf_obj_get_flags(const char *pathname, __u32 flags)

same note about bpf_obj_get_opts() instead


>  {
>         union bpf_attr attr;
>         int fd;
>
>         memset(&attr, 0, sizeof(attr));
>         attr.pathname = ptr_to_u64((void *)pathname);
> +       attr.file_flags = flags;
>
>         fd = sys_bpf_fd(BPF_OBJ_GET, &attr, sizeof(attr));
>         return libbpf_err_errno(fd);
>  }
>
> +int bpf_obj_get(const char *pathname)
> +{
> +       return bpf_obj_get_flags(pathname, 0);
> +}
> +
>  int bpf_prog_attach(int prog_fd, int target_fd, enum bpf_attach_type type,
>                     unsigned int flags)
>  {
> diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
> index 20e4c852362d..6d0ceb2e90c4 100644
> --- a/tools/lib/bpf/bpf.h
> +++ b/tools/lib/bpf/bpf.h
> @@ -339,6 +339,7 @@ LIBBPF_API int bpf_map_update_batch(int fd, const void *keys, const void *values
>                                     const struct bpf_map_batch_opts *opts);
>
>  LIBBPF_API int bpf_obj_pin(int fd, const char *pathname);
> +LIBBPF_API int bpf_obj_get_flags(const char *pathname, __u32 flags);
>  LIBBPF_API int bpf_obj_get(const char *pathname);
>
>  struct bpf_prog_attach_opts {
> diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
> index 019278e66836..6c3ace12b27b 100644
> --- a/tools/lib/bpf/libbpf.map
> +++ b/tools/lib/bpf/libbpf.map
> @@ -467,6 +467,7 @@ LIBBPF_1.0.0 {
>                 libbpf_bpf_map_type_str;
>                 libbpf_bpf_prog_type_str;
>                 bpf_map_get_fd_by_id_flags;
> +               bpf_obj_get_flags;
>
>         local: *;
>  };
> --
> 2.25.1
>