On Fri, Jul 22, 2022 at 10:20 AM Roberto Sassu <roberto.sassu@xxxxxxxxxx> wrote: > > Introduce bpf_obj_get_opts(), to let the caller pass the needed permissions > for the operation. Keep the existing bpf_obj_get() to request read-write > permissions. > > bpf_obj_get() allows the caller to get a file descriptor from a pinned > object with the provided pathname. Specifying permissions has only effect > on maps (for links, the permission must be always read-write). > > Signed-off-by: Roberto Sassu <roberto.sassu@xxxxxxxxxx> > --- > tools/lib/bpf/bpf.c | 12 +++++++++++- > tools/lib/bpf/bpf.h | 2 ++ > tools/lib/bpf/libbpf.map | 1 + > 3 files changed, 14 insertions(+), 1 deletion(-) > > diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c > index 5f2785a4c358..0df088890864 100644 > --- a/tools/lib/bpf/bpf.c > +++ b/tools/lib/bpf/bpf.c > @@ -577,18 +577,28 @@ 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_opts(const char *pathname, > + const struct bpf_get_fd_opts *opts) I'm still not sure whether it's a good idea to mix get_fd with obj_get/pin operations? [1] seems more clear. It just so happens that (differently named) flags in BPF_OBJ_GET and BPF_XXX_GET_FD_BY_ID align, but maybe we shouldn't depend on it? Also, it seems only bpf_map_get_fd_by_id currently accepts flags? So this sharing makes even more sense? [1] https://lore.kernel.org/bpf/20220719194028.4180569-1-jevburton.kernel@xxxxxxxxx/ > { > union bpf_attr attr; > int fd; > > + if (!OPTS_VALID(opts, bpf_get_fd_opts)) > + return libbpf_err(-EINVAL); > + > memset(&attr, 0, sizeof(attr)); > attr.pathname = ptr_to_u64((void *)pathname); > + attr.file_flags = OPTS_GET(opts, flags, 0); > > 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_opts(pathname, NULL); > +} > + > 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 b75fd9d37bad..e0c5018cc131 100644 > --- a/tools/lib/bpf/bpf.h > +++ b/tools/lib/bpf/bpf.h > @@ -279,6 +279,8 @@ struct bpf_get_fd_opts { > }; > #define bpf_get_fd_opts__last_field flags > > +LIBBPF_API int bpf_obj_get_opts(const char *pathname, > + const struct bpf_get_fd_opts *opts); > 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 dba97d2ef8a9..55516b19e22f 100644 > --- a/tools/lib/bpf/libbpf.map > +++ b/tools/lib/bpf/libbpf.map > @@ -368,4 +368,5 @@ LIBBPF_1.0.0 { > bpf_map_get_fd_by_id_opts; > bpf_btf_get_fd_by_id_opts; > bpf_link_get_fd_by_id_opts; > + bpf_obj_get_opts; > }; > -- > 2.25.1 >
