On Fri, Apr 23, 2021 at 02:37:28PM -0700, Martin KaFai Lau wrote:
SNIP
> +static int collect_listed_functions(struct btf_elf *btfe, GElf_Sym *sym,
> + size_t sym_sec_idx)
> +{
> + int len, digits = 0, underscores = 0;
> + const char *name;
> + char *func_name;
> +
> + if (!btfe->btf_ids_shndx ||
> + btfe->btf_ids_shndx != sym_sec_idx)
> + return 0;
> +
> + /* The kernel function in the btf id list will have symbol like:
> + * __BTF_ID__func__<kernel_func_name>__[digit]+
> + */
> + name = elf_sym__name(sym, btfe->symtab);
> + if (strncmp(name, BTF_ID_FUNC_PREFIX, BTF_ID_FUNC_PREFIX_LEN))
> + return 0;
> +
> + name += BTF_ID_FUNC_PREFIX_LEN;
> +
> + /* name: <kernel_func_name>__[digit]+
> + * Strip the ending __[digit]+
> + */
> + for (len = strlen(name); len && underscores != 2; len--) {
> + char c = name[len - 1];
> +
> + if (c == '_') {
> + if (!digits)
> + return 0;
> + underscores++;
> + } else if (isdigit(c)) {
> + if (underscores)
> + return 0;
> + digits++;
> + } else {
> + return 0;
> + }
> + }
> +
> + if (!len)
> + return 0;
> +
> + func_name = strndup(name, len);
> + if (!func_name) {
> + fprintf(stderr,
> + "Failed to alloc memory for listed function %s%s\n",
> + BTF_ID_FUNC_PREFIX, name);
> + return -1;
> + }
> +
> + if (is_listed_func(func_name)) {
> + /* already captured */
> + free(func_name);
> + return 0;
> + }
> +
> + /* grow listed_functions */
> + if (listed_functions_cnt == listed_functions_alloc) {
> + char **new;
> +
> + listed_functions_alloc = max(100,
> + listed_functions_alloc * 3 / 2);
> + new = realloc(listed_functions,
> + listed_functions_alloc * sizeof(*listed_functions));
> + if (!new) {
> + fprintf(stderr,
> + "Failed to alloc memory for listed function %s%s\n",
> + BTF_ID_FUNC_PREFIX, name);
> + free(func_name);
> + return -1;
> + }
> + listed_functions = new;
> + }
> +
> + listed_functions[listed_functions_cnt++] = func_name;
> + qsort(listed_functions, listed_functions_cnt,
> + sizeof(*listed_functions), listed_function_cmp);
I was thinking of doing this at the end in setup_functions,
but we need to do name lookups before adding.. also there are
not too many BTF_ID instances anyway
I'll run the test script with your change
jirka
