Re: [PATCHv2 bpf-next 07/24] libbpf: Add open_elf/close_elf functions

Jiri Olsa
2023-06-23T08:21:42Z

On Thu, Jun 22, 2023 at 05:33:33PM -0700, Andrii Nakryiko wrote:
> On Tue, Jun 20, 2023 at 1:37 AM Jiri Olsa <jolsa@kernel.org> wrote:
> >
> > Adding open_elf/close_elf functions and using it in
> > elf_find_func_offset_from_file function. It will be
> > used in following changes to save some code.
> >
> > Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> > ---
> > tools/lib/bpf/libbpf.c | 62 ++++++++++++++++++++++++++++++------------
> > 1 file changed, 44 insertions(+), 18 deletions(-)
> >
>
> we should definitely move all this into separate elf.c file

right, also we could use this in usdt_manager_attach_usdt as well

>
> > diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> > index cdac368c7ce1..30d9e3b69114 100644
> > --- a/tools/lib/bpf/libbpf.c
> > +++ b/tools/lib/bpf/libbpf.c
> > @@ -10927,6 +10927,45 @@ static struct elf_symbol *elf_symbol_iter_next(struct elf_symbol_iter *iter)
> > return ret;
> > }
> >
> > +struct elf_fd {
> > + Elf *elf;
> > + int fd;
> > +};
> > +
> > +static int open_elf(const char *binary_path, struct elf_fd *elf_fd)
> > +{
> > + char errmsg[STRERR_BUFSIZE];
> > + int fd, ret;
> > + Elf *elf;
> > +
> > + if (elf_version(EV_CURRENT) == EV_NONE) {
> > + pr_warn("failed to init libelf for %s\n", binary_path);
> > + return -LIBBPF_ERRNO__LIBELF;
> > + }
> > + fd = open(binary_path, O_RDONLY | O_CLOEXEC);
> > + if (fd < 0) {
> > + ret = -errno;
> > + pr_warn("failed to open %s: %s\n", binary_path,
> > + libbpf_strerror_r(ret, errmsg, sizeof(errmsg)));
>
> let's add "elf: " prefix for consistency?

ok

jirka