Subject: [PATCH 09/13] libbpf: Add libbpf__kallsyms_parse function

From: Jiri Olsa <[email-masked]>
Date: Tue, 4 Jan 2022 09:09:39 +0100

Move the kallsyms parsing in internal libbpf__kallsyms_parse
function, so it can be used from other places.

It will be used in following changes.

Signed-off-by: Jiri Olsa <[email-masked]>
---
 tools/lib/bpf/libbpf.c          | 62 ++++++++++++++++++++-------------
 tools/lib/bpf/libbpf_internal.h |  5 +++
 2 files changed, 43 insertions(+), 24 deletions(-)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 9cb99d1e2385..25512b4dbc8c 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -7146,12 +7146,10 @@ static int bpf_object__sanitize_maps(struct bpf_object *obj)
 	return 0;
 }
 
-static int bpf_object__read_kallsyms_file(struct bpf_object *obj)
+int libbpf__kallsyms_parse(void *arg, kallsyms_cb_t cb)
 {
 	char sym_type, sym_name[500];
 	unsigned long long sym_addr;
-	const struct btf_type *t;
-	struct extern_desc *ext;
 	int ret, err = 0;
 	FILE *f;
 
@@ -7170,35 +7168,51 @@ static int bpf_object__read_kallsyms_file(struct bpf_object *obj)
 		if (ret != 3) {
 			pr_warn("failed to read kallsyms entry: %d\n", ret);
 			err = -EINVAL;
-			goto out;
+			break;
 		}
 
-		ext = find_extern_by_name(obj, sym_name);
-		if (!ext || ext->type != EXT_KSYM)
-			continue;
-
-		t = btf__type_by_id(obj->btf, ext->btf_id);
-		if (!btf_is_var(t))
-			continue;
-
-		if (ext->is_set && ext->ksym.addr != sym_addr) {
-			pr_warn("extern (ksym) '%s' resolution is ambiguous: 0x%llx or 0x%llx\n",
-				sym_name, ext->ksym.addr, sym_addr);
-			err = -EINVAL;
-			goto out;
-		}
-		if (!ext->is_set) {
-			ext->is_set = true;
-			ext->ksym.addr = sym_addr;
-			pr_debug("extern (ksym) %s=0x%llx\n", sym_name, sym_addr);
-		}
+		err = cb(arg, sym_addr, sym_type, sym_name);
+		if (err)
+			break;
 	}
 
-out:
 	fclose(f);
 	return err;
 }
 
+static int kallsyms_cb(void *arg, unsigned long long sym_addr,
+		       char sym_type, const char *sym_name)
+{
+	struct bpf_object *obj = arg;
+	const struct btf_type *t;
+	struct extern_desc *ext;
+
+	ext = find_extern_by_name(obj, sym_name);
+	if (!ext || ext->type != EXT_KSYM)
+		return 0;
+
+	t = btf__type_by_id(obj->btf, ext->btf_id);
+	if (!btf_is_var(t))
+		return 0;
+
+	if (ext->is_set && ext->ksym.addr != sym_addr) {
+		pr_warn("extern (ksym) '%s' resolution is ambiguous: 0x%llx or 0x%llx\n",
+			sym_name, ext->ksym.addr, sym_addr);
+		return -EINVAL;
+	}
+	if (!ext->is_set) {
+		ext->is_set = true;
+		ext->ksym.addr = sym_addr;
+		pr_debug("extern (ksym) %s=0x%llx\n", sym_name, sym_addr);
+	}
+	return 0;
+}
+
+static int bpf_object__read_kallsyms_file(struct bpf_object *obj)
+{
+	return libbpf__kallsyms_parse(obj, kallsyms_cb);
+}
+
 static int find_ksym_btf_id(struct bpf_object *obj, const char *ksym_name,
 			    __u16 kind, struct btf **res_btf,
 			    struct module_btf **res_mod_btf)
diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h
index 1565679eb432..dc544d239509 100644
--- a/tools/lib/bpf/libbpf_internal.h
+++ b/tools/lib/bpf/libbpf_internal.h
@@ -446,6 +446,11 @@ __s32 btf__find_by_name_kind_own(const struct btf *btf, const char *type_name,
 
 extern enum libbpf_strict_mode libbpf_mode;
 
+typedef int (*kallsyms_cb_t)(void *arg, unsigned long long sym_addr,
+			     char sym_type, const char *sym_name);
+
+int libbpf__kallsyms_parse(void *arg, kallsyms_cb_t cb);
+
 /* handle direct returned errors */
 static inline int libbpf_err(int ret)
 {
-- 
2.33.1