xref: /openbmc/linux/tools/lib/bpf/btf.c (revision 78a2540e8945678b390a5f41eb82459bc6f0f36c)
11bc38b8fSAlexei Starovoitov // SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
28a138aedSMartin KaFai Lau /* Copyright (c) 2018 Facebook */
38a138aedSMartin KaFai Lau 
48a138aedSMartin KaFai Lau #include <stdlib.h>
58a138aedSMartin KaFai Lau #include <string.h>
68a138aedSMartin KaFai Lau #include <unistd.h>
78a138aedSMartin KaFai Lau #include <errno.h>
88a138aedSMartin KaFai Lau #include <linux/err.h>
98a138aedSMartin KaFai Lau #include <linux/btf.h>
108a138aedSMartin KaFai Lau #include "btf.h"
118a138aedSMartin KaFai Lau #include "bpf.h"
128a138aedSMartin KaFai Lau 
138a138aedSMartin KaFai Lau #define elog(fmt, ...) { if (err_log) err_log(fmt, ##__VA_ARGS__); }
148a138aedSMartin KaFai Lau #define max(a, b) ((a) > (b) ? (a) : (b))
158a138aedSMartin KaFai Lau #define min(a, b) ((a) < (b) ? (a) : (b))
168a138aedSMartin KaFai Lau 
178a138aedSMartin KaFai Lau #define BTF_MAX_NR_TYPES 65535
188a138aedSMartin KaFai Lau 
1992b57121SOkash Khawaja #define IS_MODIFIER(k) (((k) == BTF_KIND_TYPEDEF) || \
2092b57121SOkash Khawaja 		((k) == BTF_KIND_VOLATILE) || \
2192b57121SOkash Khawaja 		((k) == BTF_KIND_CONST) || \
2292b57121SOkash Khawaja 		((k) == BTF_KIND_RESTRICT))
2392b57121SOkash Khawaja 
248a138aedSMartin KaFai Lau static struct btf_type btf_void;
258a138aedSMartin KaFai Lau 
268a138aedSMartin KaFai Lau struct btf {
278a138aedSMartin KaFai Lau 	union {
288a138aedSMartin KaFai Lau 		struct btf_header *hdr;
298a138aedSMartin KaFai Lau 		void *data;
308a138aedSMartin KaFai Lau 	};
318a138aedSMartin KaFai Lau 	struct btf_type **types;
328a138aedSMartin KaFai Lau 	const char *strings;
338a138aedSMartin KaFai Lau 	void *nohdr_data;
345b891af7SMartin KaFai Lau 	__u32 nr_types;
355b891af7SMartin KaFai Lau 	__u32 types_size;
365b891af7SMartin KaFai Lau 	__u32 data_size;
378a138aedSMartin KaFai Lau 	int fd;
388a138aedSMartin KaFai Lau };
398a138aedSMartin KaFai Lau 
408a138aedSMartin KaFai Lau static int btf_add_type(struct btf *btf, struct btf_type *t)
418a138aedSMartin KaFai Lau {
428a138aedSMartin KaFai Lau 	if (btf->types_size - btf->nr_types < 2) {
438a138aedSMartin KaFai Lau 		struct btf_type **new_types;
445b891af7SMartin KaFai Lau 		__u32 expand_by, new_size;
458a138aedSMartin KaFai Lau 
468a138aedSMartin KaFai Lau 		if (btf->types_size == BTF_MAX_NR_TYPES)
478a138aedSMartin KaFai Lau 			return -E2BIG;
488a138aedSMartin KaFai Lau 
498a138aedSMartin KaFai Lau 		expand_by = max(btf->types_size >> 2, 16);
508a138aedSMartin KaFai Lau 		new_size = min(BTF_MAX_NR_TYPES, btf->types_size + expand_by);
518a138aedSMartin KaFai Lau 
528a138aedSMartin KaFai Lau 		new_types = realloc(btf->types, sizeof(*new_types) * new_size);
538a138aedSMartin KaFai Lau 		if (!new_types)
548a138aedSMartin KaFai Lau 			return -ENOMEM;
558a138aedSMartin KaFai Lau 
568a138aedSMartin KaFai Lau 		if (btf->nr_types == 0)
578a138aedSMartin KaFai Lau 			new_types[0] = &btf_void;
588a138aedSMartin KaFai Lau 
598a138aedSMartin KaFai Lau 		btf->types = new_types;
608a138aedSMartin KaFai Lau 		btf->types_size = new_size;
618a138aedSMartin KaFai Lau 	}
628a138aedSMartin KaFai Lau 
638a138aedSMartin KaFai Lau 	btf->types[++(btf->nr_types)] = t;
648a138aedSMartin KaFai Lau 
658a138aedSMartin KaFai Lau 	return 0;
668a138aedSMartin KaFai Lau }
678a138aedSMartin KaFai Lau 
688a138aedSMartin KaFai Lau static int btf_parse_hdr(struct btf *btf, btf_print_fn_t err_log)
698a138aedSMartin KaFai Lau {
708a138aedSMartin KaFai Lau 	const struct btf_header *hdr = btf->hdr;
715b891af7SMartin KaFai Lau 	__u32 meta_left;
728a138aedSMartin KaFai Lau 
738a138aedSMartin KaFai Lau 	if (btf->data_size < sizeof(struct btf_header)) {
748a138aedSMartin KaFai Lau 		elog("BTF header not found\n");
758a138aedSMartin KaFai Lau 		return -EINVAL;
768a138aedSMartin KaFai Lau 	}
778a138aedSMartin KaFai Lau 
788a138aedSMartin KaFai Lau 	if (hdr->magic != BTF_MAGIC) {
798a138aedSMartin KaFai Lau 		elog("Invalid BTF magic:%x\n", hdr->magic);
808a138aedSMartin KaFai Lau 		return -EINVAL;
818a138aedSMartin KaFai Lau 	}
828a138aedSMartin KaFai Lau 
838a138aedSMartin KaFai Lau 	if (hdr->version != BTF_VERSION) {
848a138aedSMartin KaFai Lau 		elog("Unsupported BTF version:%u\n", hdr->version);
858a138aedSMartin KaFai Lau 		return -ENOTSUP;
868a138aedSMartin KaFai Lau 	}
878a138aedSMartin KaFai Lau 
888a138aedSMartin KaFai Lau 	if (hdr->flags) {
898a138aedSMartin KaFai Lau 		elog("Unsupported BTF flags:%x\n", hdr->flags);
908a138aedSMartin KaFai Lau 		return -ENOTSUP;
918a138aedSMartin KaFai Lau 	}
928a138aedSMartin KaFai Lau 
938a138aedSMartin KaFai Lau 	meta_left = btf->data_size - sizeof(*hdr);
948a138aedSMartin KaFai Lau 	if (!meta_left) {
958a138aedSMartin KaFai Lau 		elog("BTF has no data\n");
968a138aedSMartin KaFai Lau 		return -EINVAL;
978a138aedSMartin KaFai Lau 	}
988a138aedSMartin KaFai Lau 
998a138aedSMartin KaFai Lau 	if (meta_left < hdr->type_off) {
1008a138aedSMartin KaFai Lau 		elog("Invalid BTF type section offset:%u\n", hdr->type_off);
1018a138aedSMartin KaFai Lau 		return -EINVAL;
1028a138aedSMartin KaFai Lau 	}
1038a138aedSMartin KaFai Lau 
1048a138aedSMartin KaFai Lau 	if (meta_left < hdr->str_off) {
1058a138aedSMartin KaFai Lau 		elog("Invalid BTF string section offset:%u\n", hdr->str_off);
1068a138aedSMartin KaFai Lau 		return -EINVAL;
1078a138aedSMartin KaFai Lau 	}
1088a138aedSMartin KaFai Lau 
1098a138aedSMartin KaFai Lau 	if (hdr->type_off >= hdr->str_off) {
1108a138aedSMartin KaFai Lau 		elog("BTF type section offset >= string section offset. No type?\n");
1118a138aedSMartin KaFai Lau 		return -EINVAL;
1128a138aedSMartin KaFai Lau 	}
1138a138aedSMartin KaFai Lau 
1148a138aedSMartin KaFai Lau 	if (hdr->type_off & 0x02) {
1158a138aedSMartin KaFai Lau 		elog("BTF type section is not aligned to 4 bytes\n");
1168a138aedSMartin KaFai Lau 		return -EINVAL;
1178a138aedSMartin KaFai Lau 	}
1188a138aedSMartin KaFai Lau 
1198a138aedSMartin KaFai Lau 	btf->nohdr_data = btf->hdr + 1;
1208a138aedSMartin KaFai Lau 
1218a138aedSMartin KaFai Lau 	return 0;
1228a138aedSMartin KaFai Lau }
1238a138aedSMartin KaFai Lau 
1248a138aedSMartin KaFai Lau static int btf_parse_str_sec(struct btf *btf, btf_print_fn_t err_log)
1258a138aedSMartin KaFai Lau {
1268a138aedSMartin KaFai Lau 	const struct btf_header *hdr = btf->hdr;
1278a138aedSMartin KaFai Lau 	const char *start = btf->nohdr_data + hdr->str_off;
1288a138aedSMartin KaFai Lau 	const char *end = start + btf->hdr->str_len;
1298a138aedSMartin KaFai Lau 
1308a138aedSMartin KaFai Lau 	if (!hdr->str_len || hdr->str_len - 1 > BTF_MAX_NAME_OFFSET ||
1318a138aedSMartin KaFai Lau 	    start[0] || end[-1]) {
1328a138aedSMartin KaFai Lau 		elog("Invalid BTF string section\n");
1338a138aedSMartin KaFai Lau 		return -EINVAL;
1348a138aedSMartin KaFai Lau 	}
1358a138aedSMartin KaFai Lau 
1368a138aedSMartin KaFai Lau 	btf->strings = start;
1378a138aedSMartin KaFai Lau 
1388a138aedSMartin KaFai Lau 	return 0;
1398a138aedSMartin KaFai Lau }
1408a138aedSMartin KaFai Lau 
1418a138aedSMartin KaFai Lau static int btf_parse_type_sec(struct btf *btf, btf_print_fn_t err_log)
1428a138aedSMartin KaFai Lau {
1438a138aedSMartin KaFai Lau 	struct btf_header *hdr = btf->hdr;
1448a138aedSMartin KaFai Lau 	void *nohdr_data = btf->nohdr_data;
1458a138aedSMartin KaFai Lau 	void *next_type = nohdr_data + hdr->type_off;
1468a138aedSMartin KaFai Lau 	void *end_type = nohdr_data + hdr->str_off;
1478a138aedSMartin KaFai Lau 
1488a138aedSMartin KaFai Lau 	while (next_type < end_type) {
1498a138aedSMartin KaFai Lau 		struct btf_type *t = next_type;
1505b891af7SMartin KaFai Lau 		__u16 vlen = BTF_INFO_VLEN(t->info);
1518a138aedSMartin KaFai Lau 		int err;
1528a138aedSMartin KaFai Lau 
1538a138aedSMartin KaFai Lau 		next_type += sizeof(*t);
1548a138aedSMartin KaFai Lau 		switch (BTF_INFO_KIND(t->info)) {
1558a138aedSMartin KaFai Lau 		case BTF_KIND_INT:
1568a138aedSMartin KaFai Lau 			next_type += sizeof(int);
1578a138aedSMartin KaFai Lau 			break;
1588a138aedSMartin KaFai Lau 		case BTF_KIND_ARRAY:
1598a138aedSMartin KaFai Lau 			next_type += sizeof(struct btf_array);
1608a138aedSMartin KaFai Lau 			break;
1618a138aedSMartin KaFai Lau 		case BTF_KIND_STRUCT:
1628a138aedSMartin KaFai Lau 		case BTF_KIND_UNION:
1638a138aedSMartin KaFai Lau 			next_type += vlen * sizeof(struct btf_member);
1648a138aedSMartin KaFai Lau 			break;
1658a138aedSMartin KaFai Lau 		case BTF_KIND_ENUM:
1668a138aedSMartin KaFai Lau 			next_type += vlen * sizeof(struct btf_enum);
1678a138aedSMartin KaFai Lau 			break;
168*78a2540eSMartin KaFai Lau 		case BTF_KIND_FUNC_PROTO:
169*78a2540eSMartin KaFai Lau 			next_type += vlen * sizeof(struct btf_param);
170*78a2540eSMartin KaFai Lau 			break;
171*78a2540eSMartin KaFai Lau 		case BTF_KIND_FUNC:
1728a138aedSMartin KaFai Lau 		case BTF_KIND_TYPEDEF:
1738a138aedSMartin KaFai Lau 		case BTF_KIND_PTR:
1748a138aedSMartin KaFai Lau 		case BTF_KIND_FWD:
1758a138aedSMartin KaFai Lau 		case BTF_KIND_VOLATILE:
1768a138aedSMartin KaFai Lau 		case BTF_KIND_CONST:
1778a138aedSMartin KaFai Lau 		case BTF_KIND_RESTRICT:
1788a138aedSMartin KaFai Lau 			break;
1798a138aedSMartin KaFai Lau 		default:
1808a138aedSMartin KaFai Lau 			elog("Unsupported BTF_KIND:%u\n",
1818a138aedSMartin KaFai Lau 			     BTF_INFO_KIND(t->info));
1828a138aedSMartin KaFai Lau 			return -EINVAL;
1838a138aedSMartin KaFai Lau 		}
1848a138aedSMartin KaFai Lau 
1858a138aedSMartin KaFai Lau 		err = btf_add_type(btf, t);
1868a138aedSMartin KaFai Lau 		if (err)
1878a138aedSMartin KaFai Lau 			return err;
1888a138aedSMartin KaFai Lau 	}
1898a138aedSMartin KaFai Lau 
1908a138aedSMartin KaFai Lau 	return 0;
1918a138aedSMartin KaFai Lau }
1928a138aedSMartin KaFai Lau 
19338d5d3b3SMartin KaFai Lau const struct btf_type *btf__type_by_id(const struct btf *btf, __u32 type_id)
1948a138aedSMartin KaFai Lau {
1958a138aedSMartin KaFai Lau 	if (type_id > btf->nr_types)
1968a138aedSMartin KaFai Lau 		return NULL;
1978a138aedSMartin KaFai Lau 
1988a138aedSMartin KaFai Lau 	return btf->types[type_id];
1998a138aedSMartin KaFai Lau }
2008a138aedSMartin KaFai Lau 
2018a138aedSMartin KaFai Lau static bool btf_type_is_void(const struct btf_type *t)
2028a138aedSMartin KaFai Lau {
2038a138aedSMartin KaFai Lau 	return t == &btf_void || BTF_INFO_KIND(t->info) == BTF_KIND_FWD;
2048a138aedSMartin KaFai Lau }
2058a138aedSMartin KaFai Lau 
2068a138aedSMartin KaFai Lau static bool btf_type_is_void_or_null(const struct btf_type *t)
2078a138aedSMartin KaFai Lau {
2088a138aedSMartin KaFai Lau 	return !t || btf_type_is_void(t);
2098a138aedSMartin KaFai Lau }
2108a138aedSMartin KaFai Lau 
2115b891af7SMartin KaFai Lau static __s64 btf_type_size(const struct btf_type *t)
2128a138aedSMartin KaFai Lau {
2138a138aedSMartin KaFai Lau 	switch (BTF_INFO_KIND(t->info)) {
2148a138aedSMartin KaFai Lau 	case BTF_KIND_INT:
2158a138aedSMartin KaFai Lau 	case BTF_KIND_STRUCT:
2168a138aedSMartin KaFai Lau 	case BTF_KIND_UNION:
2178a138aedSMartin KaFai Lau 	case BTF_KIND_ENUM:
2188a138aedSMartin KaFai Lau 		return t->size;
2198a138aedSMartin KaFai Lau 	case BTF_KIND_PTR:
2208a138aedSMartin KaFai Lau 		return sizeof(void *);
2218a138aedSMartin KaFai Lau 	default:
2228a138aedSMartin KaFai Lau 		return -EINVAL;
2238a138aedSMartin KaFai Lau 	}
2248a138aedSMartin KaFai Lau }
2258a138aedSMartin KaFai Lau 
2268a138aedSMartin KaFai Lau #define MAX_RESOLVE_DEPTH 32
2278a138aedSMartin KaFai Lau 
2285b891af7SMartin KaFai Lau __s64 btf__resolve_size(const struct btf *btf, __u32 type_id)
2298a138aedSMartin KaFai Lau {
2308a138aedSMartin KaFai Lau 	const struct btf_array *array;
2318a138aedSMartin KaFai Lau 	const struct btf_type *t;
2325b891af7SMartin KaFai Lau 	__u32 nelems = 1;
2335b891af7SMartin KaFai Lau 	__s64 size = -1;
2348a138aedSMartin KaFai Lau 	int i;
2358a138aedSMartin KaFai Lau 
23692b57121SOkash Khawaja 	t = btf__type_by_id(btf, type_id);
2378a138aedSMartin KaFai Lau 	for (i = 0; i < MAX_RESOLVE_DEPTH && !btf_type_is_void_or_null(t);
2388a138aedSMartin KaFai Lau 	     i++) {
2398a138aedSMartin KaFai Lau 		size = btf_type_size(t);
2408a138aedSMartin KaFai Lau 		if (size >= 0)
2418a138aedSMartin KaFai Lau 			break;
2428a138aedSMartin KaFai Lau 
2438a138aedSMartin KaFai Lau 		switch (BTF_INFO_KIND(t->info)) {
2448a138aedSMartin KaFai Lau 		case BTF_KIND_TYPEDEF:
2458a138aedSMartin KaFai Lau 		case BTF_KIND_VOLATILE:
2468a138aedSMartin KaFai Lau 		case BTF_KIND_CONST:
2478a138aedSMartin KaFai Lau 		case BTF_KIND_RESTRICT:
2488a138aedSMartin KaFai Lau 			type_id = t->type;
2498a138aedSMartin KaFai Lau 			break;
2508a138aedSMartin KaFai Lau 		case BTF_KIND_ARRAY:
2518a138aedSMartin KaFai Lau 			array = (const struct btf_array *)(t + 1);
2528a138aedSMartin KaFai Lau 			if (nelems && array->nelems > UINT32_MAX / nelems)
2538a138aedSMartin KaFai Lau 				return -E2BIG;
2548a138aedSMartin KaFai Lau 			nelems *= array->nelems;
2558a138aedSMartin KaFai Lau 			type_id = array->type;
2568a138aedSMartin KaFai Lau 			break;
2578a138aedSMartin KaFai Lau 		default:
2588a138aedSMartin KaFai Lau 			return -EINVAL;
2598a138aedSMartin KaFai Lau 		}
2608a138aedSMartin KaFai Lau 
26192b57121SOkash Khawaja 		t = btf__type_by_id(btf, type_id);
2628a138aedSMartin KaFai Lau 	}
2638a138aedSMartin KaFai Lau 
2648a138aedSMartin KaFai Lau 	if (size < 0)
2658a138aedSMartin KaFai Lau 		return -EINVAL;
2668a138aedSMartin KaFai Lau 
2678a138aedSMartin KaFai Lau 	if (nelems && size > UINT32_MAX / nelems)
2688a138aedSMartin KaFai Lau 		return -E2BIG;
2698a138aedSMartin KaFai Lau 
2708a138aedSMartin KaFai Lau 	return nelems * size;
2718a138aedSMartin KaFai Lau }
2728a138aedSMartin KaFai Lau 
27392b57121SOkash Khawaja int btf__resolve_type(const struct btf *btf, __u32 type_id)
27492b57121SOkash Khawaja {
27592b57121SOkash Khawaja 	const struct btf_type *t;
27692b57121SOkash Khawaja 	int depth = 0;
27792b57121SOkash Khawaja 
27892b57121SOkash Khawaja 	t = btf__type_by_id(btf, type_id);
27992b57121SOkash Khawaja 	while (depth < MAX_RESOLVE_DEPTH &&
28092b57121SOkash Khawaja 	       !btf_type_is_void_or_null(t) &&
28192b57121SOkash Khawaja 	       IS_MODIFIER(BTF_INFO_KIND(t->info))) {
28292b57121SOkash Khawaja 		type_id = t->type;
28392b57121SOkash Khawaja 		t = btf__type_by_id(btf, type_id);
28492b57121SOkash Khawaja 		depth++;
28592b57121SOkash Khawaja 	}
28692b57121SOkash Khawaja 
28792b57121SOkash Khawaja 	if (depth == MAX_RESOLVE_DEPTH || btf_type_is_void_or_null(t))
28892b57121SOkash Khawaja 		return -EINVAL;
28992b57121SOkash Khawaja 
29092b57121SOkash Khawaja 	return type_id;
29192b57121SOkash Khawaja }
29292b57121SOkash Khawaja 
2935b891af7SMartin KaFai Lau __s32 btf__find_by_name(const struct btf *btf, const char *type_name)
2948a138aedSMartin KaFai Lau {
2955b891af7SMartin KaFai Lau 	__u32 i;
2968a138aedSMartin KaFai Lau 
2978a138aedSMartin KaFai Lau 	if (!strcmp(type_name, "void"))
2988a138aedSMartin KaFai Lau 		return 0;
2998a138aedSMartin KaFai Lau 
3008a138aedSMartin KaFai Lau 	for (i = 1; i <= btf->nr_types; i++) {
3018a138aedSMartin KaFai Lau 		const struct btf_type *t = btf->types[i];
30292b57121SOkash Khawaja 		const char *name = btf__name_by_offset(btf, t->name_off);
3038a138aedSMartin KaFai Lau 
3048a138aedSMartin KaFai Lau 		if (name && !strcmp(type_name, name))
3058a138aedSMartin KaFai Lau 			return i;
3068a138aedSMartin KaFai Lau 	}
3078a138aedSMartin KaFai Lau 
3088a138aedSMartin KaFai Lau 	return -ENOENT;
3098a138aedSMartin KaFai Lau }
3108a138aedSMartin KaFai Lau 
3118a138aedSMartin KaFai Lau void btf__free(struct btf *btf)
3128a138aedSMartin KaFai Lau {
3138a138aedSMartin KaFai Lau 	if (!btf)
3148a138aedSMartin KaFai Lau 		return;
3158a138aedSMartin KaFai Lau 
3168a138aedSMartin KaFai Lau 	if (btf->fd != -1)
3178a138aedSMartin KaFai Lau 		close(btf->fd);
3188a138aedSMartin KaFai Lau 
3198a138aedSMartin KaFai Lau 	free(btf->data);
3208a138aedSMartin KaFai Lau 	free(btf->types);
3218a138aedSMartin KaFai Lau 	free(btf);
3228a138aedSMartin KaFai Lau }
3238a138aedSMartin KaFai Lau 
3245b891af7SMartin KaFai Lau struct btf *btf__new(__u8 *data, __u32 size, btf_print_fn_t err_log)
3258a138aedSMartin KaFai Lau {
3265b891af7SMartin KaFai Lau 	__u32 log_buf_size = 0;
3278a138aedSMartin KaFai Lau 	char *log_buf = NULL;
3288a138aedSMartin KaFai Lau 	struct btf *btf;
3298a138aedSMartin KaFai Lau 	int err;
3308a138aedSMartin KaFai Lau 
3318a138aedSMartin KaFai Lau 	btf = calloc(1, sizeof(struct btf));
3328a138aedSMartin KaFai Lau 	if (!btf)
3338a138aedSMartin KaFai Lau 		return ERR_PTR(-ENOMEM);
3348a138aedSMartin KaFai Lau 
3358a138aedSMartin KaFai Lau 	btf->fd = -1;
3368a138aedSMartin KaFai Lau 
3378a138aedSMartin KaFai Lau 	if (err_log) {
3388a138aedSMartin KaFai Lau 		log_buf = malloc(BPF_LOG_BUF_SIZE);
3398a138aedSMartin KaFai Lau 		if (!log_buf) {
3408a138aedSMartin KaFai Lau 			err = -ENOMEM;
3418a138aedSMartin KaFai Lau 			goto done;
3428a138aedSMartin KaFai Lau 		}
3438a138aedSMartin KaFai Lau 		*log_buf = 0;
3448a138aedSMartin KaFai Lau 		log_buf_size = BPF_LOG_BUF_SIZE;
3458a138aedSMartin KaFai Lau 	}
3468a138aedSMartin KaFai Lau 
3478a138aedSMartin KaFai Lau 	btf->data = malloc(size);
3488a138aedSMartin KaFai Lau 	if (!btf->data) {
3498a138aedSMartin KaFai Lau 		err = -ENOMEM;
3508a138aedSMartin KaFai Lau 		goto done;
3518a138aedSMartin KaFai Lau 	}
3528a138aedSMartin KaFai Lau 
3538a138aedSMartin KaFai Lau 	memcpy(btf->data, data, size);
3548a138aedSMartin KaFai Lau 	btf->data_size = size;
3558a138aedSMartin KaFai Lau 
3568a138aedSMartin KaFai Lau 	btf->fd = bpf_load_btf(btf->data, btf->data_size,
3578a138aedSMartin KaFai Lau 			       log_buf, log_buf_size, false);
3588a138aedSMartin KaFai Lau 
3598a138aedSMartin KaFai Lau 	if (btf->fd == -1) {
3608a138aedSMartin KaFai Lau 		err = -errno;
3618a138aedSMartin KaFai Lau 		elog("Error loading BTF: %s(%d)\n", strerror(errno), errno);
3628a138aedSMartin KaFai Lau 		if (log_buf && *log_buf)
3638a138aedSMartin KaFai Lau 			elog("%s\n", log_buf);
3648a138aedSMartin KaFai Lau 		goto done;
3658a138aedSMartin KaFai Lau 	}
3668a138aedSMartin KaFai Lau 
3678a138aedSMartin KaFai Lau 	err = btf_parse_hdr(btf, err_log);
3688a138aedSMartin KaFai Lau 	if (err)
3698a138aedSMartin KaFai Lau 		goto done;
3708a138aedSMartin KaFai Lau 
3718a138aedSMartin KaFai Lau 	err = btf_parse_str_sec(btf, err_log);
3728a138aedSMartin KaFai Lau 	if (err)
3738a138aedSMartin KaFai Lau 		goto done;
3748a138aedSMartin KaFai Lau 
3758a138aedSMartin KaFai Lau 	err = btf_parse_type_sec(btf, err_log);
3768a138aedSMartin KaFai Lau 
3778a138aedSMartin KaFai Lau done:
3788a138aedSMartin KaFai Lau 	free(log_buf);
3798a138aedSMartin KaFai Lau 
3808a138aedSMartin KaFai Lau 	if (err) {
3818a138aedSMartin KaFai Lau 		btf__free(btf);
3828a138aedSMartin KaFai Lau 		return ERR_PTR(err);
3838a138aedSMartin KaFai Lau 	}
3848a138aedSMartin KaFai Lau 
3858a138aedSMartin KaFai Lau 	return btf;
3868a138aedSMartin KaFai Lau }
3878a138aedSMartin KaFai Lau 
3888a138aedSMartin KaFai Lau int btf__fd(const struct btf *btf)
3898a138aedSMartin KaFai Lau {
3908a138aedSMartin KaFai Lau 	return btf->fd;
3918a138aedSMartin KaFai Lau }
39292b57121SOkash Khawaja 
39392b57121SOkash Khawaja const char *btf__name_by_offset(const struct btf *btf, __u32 offset)
39492b57121SOkash Khawaja {
39592b57121SOkash Khawaja 	if (offset < btf->hdr->str_len)
39692b57121SOkash Khawaja 		return &btf->strings[offset];
39792b57121SOkash Khawaja 	else
39892b57121SOkash Khawaja 		return NULL;
39992b57121SOkash Khawaja }
400