bpftool: clean-up usage of libbpf_get_error()

bpftool is now totally compliant with libbpf 1.0 mode and is not
expected to be compiled with pre-1.0, let's clean-up the usage of
libbpf_get_error().

The changes stay aligned with returned errors always negative.

- In tools/bpf/bpftool/btf.c This fixes an uninitialized local
variable `err` in function do_dump() because it may now be returned
without having been set.
- This also removes the checks on NULL pointers before calling
btf__free() because that function already does the check.

Signed-off-by: Sahid Orentino Ferdjaoui <sahid.ferdjaoui@industrialdiscipline.com>
Link: https://lore.kernel.org/r/20221120112515.38165-5-sahid.ferdjaoui@industrialdiscipline.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 6 insertions, 4 deletions

diff --git a/tools/bpf/bpftool/iter.c b/tools/bpf/bpftool/iter.c
index a3e6b167153d..9a1d2365a297 100644
--- a/tools/bpf/bpftool/iter.c
+++ b/tools/bpf/bpftool/iter.c
@@ -4,6 +4,7 @@
 #ifndef _GNU_SOURCE
 #define _GNU_SOURCE
 #endif
+#include <errno.h>
 #include <unistd.h>
 #include <linux/err.h>
 #include <bpf/libbpf.h>
@@ -48,8 +49,8 @@ static int do_pin(int argc, char **argv)
 	}
 
 	obj = bpf_object__open(objfile);
-	err = libbpf_get_error(obj);
-	if (err) {
+	if (!obj) {
+		err = -errno;
 		p_err("can't open objfile %s", objfile);
 		goto close_map_fd;
 	}
@@ -62,13 +63,14 @@ static int do_pin(int argc, char **argv)
 
 	prog = bpf_object__next_program(obj, NULL);
 	if (!prog) {
+		err = -errno;
 		p_err("can't find bpf program in objfile %s", objfile);
 		goto close_obj;
 	}
 
 	link = bpf_program__attach_iter(prog, &iter_opts);
-	err = libbpf_get_error(link);
-	if (err) {
+	if (!link) {
+		err = -errno;
 		p_err("attach_iter failed for program %s",
 		      bpf_program__name(prog));
 		goto close_obj;