[PATCH bpf-next v4 2/8] resolve_btfids: Factor out load_btf()

[Ihor Solodrai <ihor.solodrai@linux.dev>]

Increase the lifetime of parsed BTF in resolve_btfids by factoring
load_btf() routine out of symbols_resolve() and storing the base_btf
and btf pointers in the struct object.

Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
---
 tools/bpf/resolve_btfids/main.c | 47 ++++++++++++++++++++++++---------
 1 file changed, 34 insertions(+), 13 deletions(-)

diff --git a/tools/bpf/resolve_btfids/main.c b/tools/bpf/resolve_btfids/main.c
index 164f0c941f04..b4caae1170dd 100644
--- a/tools/bpf/resolve_btfids/main.c
+++ b/tools/bpf/resolve_btfids/main.c
@@ -116,6 +116,9 @@ struct object {
 	const char *btf_path;
 	const char *base_btf_path;
 
+	struct btf *btf;
+	struct btf *base_btf;
+
 	struct {
 		int		 fd;
 		Elf		*elf;
@@ -529,16 +532,10 @@ static int symbols_collect(struct object *obj)
 	return 0;
 }
 
-static int symbols_resolve(struct object *obj)
+static int load_btf(struct object *obj)
 {
-	int nr_typedefs = obj->nr_typedefs;
-	int nr_structs  = obj->nr_structs;
-	int nr_unions   = obj->nr_unions;
-	int nr_funcs    = obj->nr_funcs;
-	struct btf *base_btf = NULL;
-	int err, type_id;
-	struct btf *btf;
-	__u32 nr_types;
+	struct btf *base_btf = NULL, *btf = NULL;
+	int err;
 
 	if (obj->base_btf_path) {
 		base_btf = btf__parse(obj->base_btf_path, NULL);
@@ -546,7 +543,7 @@ static int symbols_resolve(struct object *obj)
 		if (err) {
 			pr_err("FAILED: load base BTF from %s: %s\n",
 			       obj->base_btf_path, strerror(-err));
-			return -1;
+			goto out_err;
 		}
 	}
 
@@ -555,9 +552,30 @@ static int symbols_resolve(struct object *obj)
 	if (err) {
 		pr_err("FAILED: load BTF from %s: %s\n",
 			obj->btf_path ?: obj->path, strerror(-err));
-		goto out;
+		goto out_err;
 	}
 
+	obj->base_btf = base_btf;
+	obj->btf = btf;
+
+	return 0;
+
+out_err:
+	btf__free(base_btf);
+	btf__free(btf);
+	return err;
+}
+
+static int symbols_resolve(struct object *obj)
+{
+	int nr_typedefs = obj->nr_typedefs;
+	int nr_structs  = obj->nr_structs;
+	int nr_unions   = obj->nr_unions;
+	int nr_funcs    = obj->nr_funcs;
+	struct btf *btf = obj->btf;
+	int err, type_id;
+	__u32 nr_types;
+
 	err = -1;
 	nr_types = btf__type_cnt(btf);
 
@@ -615,8 +633,6 @@ static int symbols_resolve(struct object *obj)
 
 	err = 0;
 out:
-	btf__free(base_btf);
-	btf__free(btf);
 	return err;
 }
 
@@ -824,6 +840,9 @@ int main(int argc, const char **argv)
 	if (symbols_collect(&obj))
 		goto out;
 
+	if (load_btf(&obj))
+		goto out;
+
 	if (symbols_resolve(&obj))
 		goto out;
 
@@ -833,6 +852,8 @@ int main(int argc, const char **argv)
 	if (!(fatal_warnings && warnings))
 		err = 0;
 out:
+	btf__free(obj.base_btf);
+	btf__free(obj.btf);
 	if (obj.efile.elf) {
 		elf_end(obj.efile.elf);
 		close(obj.efile.fd);
-- 
2.52.0