tools/bpftool: Fix error handing in do_skeleton()

Fix pass 0 to PTR_ERR, also dump more err info using
libbpf_strerror.

Fixes: 5dc7a8b21144 ("bpftool, selftests/bpf: Embed object file inside skeleton")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Quentin Monnet <quentin@isovalent.com>
Link: https://lore.kernel.org/bpf/20200717123059.29624-1-yuehaibing@huawei.com

diff --git a/tools/bpf/bpftool/gen.c b/tools/bpf/bpftool/gen.c
index b59d26e89367248064473cfbe10172519331f14d..8a4c2b3b0cd63ef13bec9cfb4f5573933788cc9b 100644 (file)
--- a/tools/bpf/bpftool/gen.c
+++ b/tools/bpf/bpftool/gen.c
@@ -302,8 +302,11 @@ static int do_skeleton(int argc, char **argv)
        opts.object_name = obj_name;
        obj = bpf_object__open_mem(obj_data, file_sz, &opts);
        if (IS_ERR(obj)) {
+               char err_buf[256];
+
+               libbpf_strerror(PTR_ERR(obj), err_buf, sizeof(err_buf));
+               p_err("failed to open BPF object file: %s", err_buf);
                obj = NULL;
-               p_err("failed to open BPF object file: %ld", PTR_ERR(obj));
                goto out;
        }