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Diffstat (limited to 'tools/lib/bpf/btf.c')
-rw-r--r--tools/lib/bpf/btf.c393
1 files changed, 393 insertions, 0 deletions
diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
index 449591aa9900..d682d3b8f7b9 100644
--- a/tools/lib/bpf/btf.c
+++ b/tools/lib/bpf/btf.c
@@ -37,6 +37,48 @@ struct btf {
int fd;
};
+struct btf_ext_info {
+ /*
+ * info points to a deep copy of the individual info section
+ * (e.g. func_info and line_info) from the .BTF.ext.
+ * It does not include the __u32 rec_size.
+ */
+ void *info;
+ __u32 rec_size;
+ __u32 len;
+};
+
+struct btf_ext {
+ struct btf_ext_info func_info;
+ struct btf_ext_info line_info;
+};
+
+struct btf_ext_info_sec {
+ __u32 sec_name_off;
+ __u32 num_info;
+ /* Followed by num_info * record_size number of bytes */
+ __u8 data[0];
+};
+
+/* The minimum bpf_func_info checked by the loader */
+struct bpf_func_info_min {
+ __u32 insn_off;
+ __u32 type_id;
+};
+
+/* The minimum bpf_line_info checked by the loader */
+struct bpf_line_info_min {
+ __u32 insn_off;
+ __u32 file_name_off;
+ __u32 line_off;
+ __u32 line_col;
+};
+
+static inline __u64 ptr_to_u64(const void *ptr)
+{
+ return (__u64) (unsigned long) ptr;
+}
+
static int btf_add_type(struct btf *btf, struct btf_type *t)
{
if (btf->types_size - btf->nr_types < 2) {
@@ -165,6 +207,10 @@ static int btf_parse_type_sec(struct btf *btf, btf_print_fn_t err_log)
case BTF_KIND_ENUM:
next_type += vlen * sizeof(struct btf_enum);
break;
+ case BTF_KIND_FUNC_PROTO:
+ next_type += vlen * sizeof(struct btf_param);
+ break;
+ case BTF_KIND_FUNC:
case BTF_KIND_TYPEDEF:
case BTF_KIND_PTR:
case BTF_KIND_FWD:
@@ -393,3 +439,350 @@ const char *btf__name_by_offset(const struct btf *btf, __u32 offset)
else
return NULL;
}
+
+int btf__get_from_id(__u32 id, struct btf **btf)
+{
+ struct bpf_btf_info btf_info = { 0 };
+ __u32 len = sizeof(btf_info);
+ __u32 last_size;
+ int btf_fd;
+ void *ptr;
+ int err;
+
+ err = 0;
+ *btf = NULL;
+ btf_fd = bpf_btf_get_fd_by_id(id);
+ if (btf_fd < 0)
+ return 0;
+
+ /* we won't know btf_size until we call bpf_obj_get_info_by_fd(). so
+ * let's start with a sane default - 4KiB here - and resize it only if
+ * bpf_obj_get_info_by_fd() needs a bigger buffer.
+ */
+ btf_info.btf_size = 4096;
+ last_size = btf_info.btf_size;
+ ptr = malloc(last_size);
+ if (!ptr) {
+ err = -ENOMEM;
+ goto exit_free;
+ }
+
+ bzero(ptr, last_size);
+ btf_info.btf = ptr_to_u64(ptr);
+ err = bpf_obj_get_info_by_fd(btf_fd, &btf_info, &len);
+
+ if (!err && btf_info.btf_size > last_size) {
+ void *temp_ptr;
+
+ last_size = btf_info.btf_size;
+ temp_ptr = realloc(ptr, last_size);
+ if (!temp_ptr) {
+ err = -ENOMEM;
+ goto exit_free;
+ }
+ ptr = temp_ptr;
+ bzero(ptr, last_size);
+ btf_info.btf = ptr_to_u64(ptr);
+ err = bpf_obj_get_info_by_fd(btf_fd, &btf_info, &len);
+ }
+
+ if (err || btf_info.btf_size > last_size) {
+ err = errno;
+ goto exit_free;
+ }
+
+ *btf = btf__new((__u8 *)(long)btf_info.btf, btf_info.btf_size, NULL);
+ if (IS_ERR(*btf)) {
+ err = PTR_ERR(*btf);
+ *btf = NULL;
+ }
+
+exit_free:
+ close(btf_fd);
+ free(ptr);
+
+ return err;
+}
+
+struct btf_ext_sec_copy_param {
+ __u32 off;
+ __u32 len;
+ __u32 min_rec_size;
+ struct btf_ext_info *ext_info;
+ const char *desc;
+};
+
+static int btf_ext_copy_info(struct btf_ext *btf_ext,
+ __u8 *data, __u32 data_size,
+ struct btf_ext_sec_copy_param *ext_sec,
+ btf_print_fn_t err_log)
+{
+ const struct btf_ext_header *hdr = (struct btf_ext_header *)data;
+ const struct btf_ext_info_sec *sinfo;
+ struct btf_ext_info *ext_info;
+ __u32 info_left, record_size;
+ /* The start of the info sec (including the __u32 record_size). */
+ const void *info;
+
+ /* data and data_size do not include btf_ext_header from now on */
+ data = data + hdr->hdr_len;
+ data_size -= hdr->hdr_len;
+
+ if (ext_sec->off & 0x03) {
+ elog(".BTF.ext %s section is not aligned to 4 bytes\n",
+ ext_sec->desc);
+ return -EINVAL;
+ }
+
+ if (data_size < ext_sec->off ||
+ ext_sec->len > data_size - ext_sec->off) {
+ elog("%s section (off:%u len:%u) is beyond the end of the ELF section .BTF.ext\n",
+ ext_sec->desc, ext_sec->off, ext_sec->len);
+ return -EINVAL;
+ }
+
+ info = data + ext_sec->off;
+ info_left = ext_sec->len;
+
+ /* At least a record size */
+ if (info_left < sizeof(__u32)) {
+ elog(".BTF.ext %s record size not found\n", ext_sec->desc);
+ return -EINVAL;
+ }
+
+ /* The record size needs to meet the minimum standard */
+ record_size = *(__u32 *)info;
+ if (record_size < ext_sec->min_rec_size ||
+ record_size & 0x03) {
+ elog("%s section in .BTF.ext has invalid record size %u\n",
+ ext_sec->desc, record_size);
+ return -EINVAL;
+ }
+
+ sinfo = info + sizeof(__u32);
+ info_left -= sizeof(__u32);
+
+ /* If no records, return failure now so .BTF.ext won't be used. */
+ if (!info_left) {
+ elog("%s section in .BTF.ext has no records", ext_sec->desc);
+ return -EINVAL;
+ }
+
+ while (info_left) {
+ unsigned int sec_hdrlen = sizeof(struct btf_ext_info_sec);
+ __u64 total_record_size;
+ __u32 num_records;
+
+ if (info_left < sec_hdrlen) {
+ elog("%s section header is not found in .BTF.ext\n",
+ ext_sec->desc);
+ return -EINVAL;
+ }
+
+ num_records = sinfo->num_info;
+ if (num_records == 0) {
+ elog("%s section has incorrect num_records in .BTF.ext\n",
+ ext_sec->desc);
+ return -EINVAL;
+ }
+
+ total_record_size = sec_hdrlen +
+ (__u64)num_records * record_size;
+ if (info_left < total_record_size) {
+ elog("%s section has incorrect num_records in .BTF.ext\n",
+ ext_sec->desc);
+ return -EINVAL;
+ }
+
+ info_left -= total_record_size;
+ sinfo = (void *)sinfo + total_record_size;
+ }
+
+ ext_info = ext_sec->ext_info;
+ ext_info->len = ext_sec->len - sizeof(__u32);
+ ext_info->rec_size = record_size;
+ ext_info->info = malloc(ext_info->len);
+ if (!ext_info->info)
+ return -ENOMEM;
+ memcpy(ext_info->info, info + sizeof(__u32), ext_info->len);
+
+ return 0;
+}
+
+static int btf_ext_copy_func_info(struct btf_ext *btf_ext,
+ __u8 *data, __u32 data_size,
+ btf_print_fn_t err_log)
+{
+ const struct btf_ext_header *hdr = (struct btf_ext_header *)data;
+ struct btf_ext_sec_copy_param param = {
+ .off = hdr->func_info_off,
+ .len = hdr->func_info_len,
+ .min_rec_size = sizeof(struct bpf_func_info_min),
+ .ext_info = &btf_ext->func_info,
+ .desc = "func_info"
+ };
+
+ return btf_ext_copy_info(btf_ext, data, data_size, &param, err_log);
+}
+
+static int btf_ext_copy_line_info(struct btf_ext *btf_ext,
+ __u8 *data, __u32 data_size,
+ btf_print_fn_t err_log)
+{
+ const struct btf_ext_header *hdr = (struct btf_ext_header *)data;
+ struct btf_ext_sec_copy_param param = {
+ .off = hdr->line_info_off,
+ .len = hdr->line_info_len,
+ .min_rec_size = sizeof(struct bpf_line_info_min),
+ .ext_info = &btf_ext->line_info,
+ .desc = "line_info",
+ };
+
+ return btf_ext_copy_info(btf_ext, data, data_size, &param, err_log);
+}
+
+static int btf_ext_parse_hdr(__u8 *data, __u32 data_size,
+ btf_print_fn_t err_log)
+{
+ const struct btf_ext_header *hdr = (struct btf_ext_header *)data;
+
+ if (data_size < offsetof(struct btf_ext_header, func_info_off) ||
+ data_size < hdr->hdr_len) {
+ elog("BTF.ext header not found");
+ return -EINVAL;
+ }
+
+ if (hdr->magic != BTF_MAGIC) {
+ elog("Invalid BTF.ext magic:%x\n", hdr->magic);
+ return -EINVAL;
+ }
+
+ if (hdr->version != BTF_VERSION) {
+ elog("Unsupported BTF.ext version:%u\n", hdr->version);
+ return -ENOTSUP;
+ }
+
+ if (hdr->flags) {
+ elog("Unsupported BTF.ext flags:%x\n", hdr->flags);
+ return -ENOTSUP;
+ }
+
+ if (data_size == hdr->hdr_len) {
+ elog("BTF.ext has no data\n");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+void btf_ext__free(struct btf_ext *btf_ext)
+{
+ if (!btf_ext)
+ return;
+
+ free(btf_ext->func_info.info);
+ free(btf_ext->line_info.info);
+ free(btf_ext);
+}
+
+struct btf_ext *btf_ext__new(__u8 *data, __u32 size, btf_print_fn_t err_log)
+{
+ struct btf_ext *btf_ext;
+ int err;
+
+ err = btf_ext_parse_hdr(data, size, err_log);
+ if (err)
+ return ERR_PTR(err);
+
+ btf_ext = calloc(1, sizeof(struct btf_ext));
+ if (!btf_ext)
+ return ERR_PTR(-ENOMEM);
+
+ err = btf_ext_copy_func_info(btf_ext, data, size, err_log);
+ if (err) {
+ btf_ext__free(btf_ext);
+ return ERR_PTR(err);
+ }
+
+ err = btf_ext_copy_line_info(btf_ext, data, size, err_log);
+ if (err) {
+ btf_ext__free(btf_ext);
+ return ERR_PTR(err);
+ }
+
+ return btf_ext;
+}
+
+static int btf_ext_reloc_info(const struct btf *btf,
+ const struct btf_ext_info *ext_info,
+ const char *sec_name, __u32 insns_cnt,
+ void **info, __u32 *cnt)
+{
+ __u32 sec_hdrlen = sizeof(struct btf_ext_info_sec);
+ __u32 i, record_size, existing_len, records_len;
+ struct btf_ext_info_sec *sinfo;
+ const char *info_sec_name;
+ __u64 remain_len;
+ void *data;
+
+ record_size = ext_info->rec_size;
+ sinfo = ext_info->info;
+ remain_len = ext_info->len;
+ while (remain_len > 0) {
+ records_len = sinfo->num_info * record_size;
+ info_sec_name = btf__name_by_offset(btf, sinfo->sec_name_off);
+ if (strcmp(info_sec_name, sec_name)) {
+ remain_len -= sec_hdrlen + records_len;
+ sinfo = (void *)sinfo + sec_hdrlen + records_len;
+ continue;
+ }
+
+ existing_len = (*cnt) * record_size;
+ data = realloc(*info, existing_len + records_len);
+ if (!data)
+ return -ENOMEM;
+
+ memcpy(data + existing_len, sinfo->data, records_len);
+ /* adjust insn_off only, the rest data will be passed
+ * to the kernel.
+ */
+ for (i = 0; i < sinfo->num_info; i++) {
+ __u32 *insn_off;
+
+ insn_off = data + existing_len + (i * record_size);
+ *insn_off = *insn_off / sizeof(struct bpf_insn) +
+ insns_cnt;
+ }
+ *info = data;
+ *cnt += sinfo->num_info;
+ return 0;
+ }
+
+ return -ENOENT;
+}
+
+int btf_ext__reloc_func_info(const struct btf *btf, const struct btf_ext *btf_ext,
+ const char *sec_name, __u32 insns_cnt,
+ void **func_info, __u32 *cnt)
+{
+ return btf_ext_reloc_info(btf, &btf_ext->func_info, sec_name,
+ insns_cnt, func_info, cnt);
+}
+
+int btf_ext__reloc_line_info(const struct btf *btf, const struct btf_ext *btf_ext,
+ const char *sec_name, __u32 insns_cnt,
+ void **line_info, __u32 *cnt)
+{
+ return btf_ext_reloc_info(btf, &btf_ext->line_info, sec_name,
+ insns_cnt, line_info, cnt);
+}
+
+__u32 btf_ext__func_info_rec_size(const struct btf_ext *btf_ext)
+{
+ return btf_ext->func_info.rec_size;
+}
+
+__u32 btf_ext__line_info_rec_size(const struct btf_ext *btf_ext)
+{
+ return btf_ext->line_info.rec_size;
+}
generated by cgit v1.2.3-70-g09d2 (git 2.51.1) at 2025-11-04 01:55:08 +0000