On Tue, Apr 27, 2021 at 01:42:40PM +0200, Jiri Olsa wrote:
> 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..
I am planning to just use btf__add_str() as Andrii suggested.
Then most of these will go away.
