1 // SPDX-License-Identifier: GPL-2.0 2 #include <linux/btf.h> 3 #include <linux/kernel.h> 4 5 #include "trace_btf.h" 6 7 /* 8 * Find a function proto type by name, and return the btf_type with its btf 9 * in *@btf_p. Return NULL if not found. 10 * Note that caller has to call btf_put(*@btf_p) after using the btf_type. 11 */ 12 const struct btf_type *btf_find_func_proto(const char *func_name, struct btf **btf_p) 13 { 14 const struct btf_type *t; 15 s32 id; 16 17 id = bpf_find_btf_id(func_name, BTF_KIND_FUNC, btf_p); 18 if (id < 0) 19 return NULL; 20 21 /* Get BTF_KIND_FUNC type */ 22 t = btf_type_by_id(*btf_p, id); 23 if (!t || !btf_type_is_func(t)) 24 goto err; 25 26 /* The type of BTF_KIND_FUNC is BTF_KIND_FUNC_PROTO */ 27 t = btf_type_by_id(*btf_p, t->type); 28 if (!t || !btf_type_is_func_proto(t)) 29 goto err; 30 31 return t; 32 err: 33 btf_put(*btf_p); 34 return NULL; 35 } 36 37 /* 38 * Get function parameter with the number of parameters. 39 * This can return NULL if the function has no parameters. 40 * It can return -EINVAL if the @func_proto is not a function proto type. 41 */ 42 const struct btf_param *btf_get_func_param(const struct btf_type *func_proto, s32 *nr) 43 { 44 if (!btf_type_is_func_proto(func_proto)) 45 return ERR_PTR(-EINVAL); 46 47 *nr = btf_type_vlen(func_proto); 48 if (*nr > 0) 49 return (const struct btf_param *)(func_proto + 1); 50 else 51 return NULL; 52 } 53 54