On Tue, Jul 04, 2023 at 04:07:48PM +0200, Jiri Olsa wrote:
> On Tue, Jul 04, 2023 at 09:33:15AM +0800, Jackie Liu wrote:
>
> SNIP
>
> > >
> > > should you check if you found anything (infos.cnt != 0) and return early
> > > if there's nothing found
> > >
> > > > +
> > > > + /* sort available functions */
> > > > + qsort(infos.syms, infos.cnt, sizeof(void *), qsort_compare_function);
> > > > +
> > > > + f = fopen("/proc/kallsyms", "r");
> > >
> > > why not use libbpf_kallsyms_parse for kallsyms parsing? the call below
> > > would be in its callback
> >
> > This place cannot directly use libbpf_kallsyms_parse, because we need
> > info.syms, this value cannot be passed into the parameters of
> > libbpf_kallsyms_parse,
>
> hum, libbpf_kallsyms_parse takes 'void *ctx', so you can pass anything
> you want right?
somthing like below should save some lines and ease up error handling
I'd add similar parse functions for both available_filter_functions and
available_filter_functions_addrs and add the logic to callbacks
jirka
---
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index b9282ef3f8a7..04b980293240 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -10559,8 +10559,31 @@ static int bsearch_compare_function(const void *a, const void *b)
return strcmp((const char *)a, *(const char **)b);
}
+struct avail_kallsyms_data {
+ const char **syms;
+ struct kprobe_multi_resolve *res;
+};
+
+static int avail_kallsyms_cb(unsigned long long sym_addr, char sym_type,
+ const char *sym_name, void *ctx)
+{
+ struct avail_kallsyms_data *data = ctx;
+ struct kprobe_multi_resolve *res = data->res;
+
+ if (!bsearch(&sym_name, data->syms, cnt, sizeof(void *), bsearch_compare_function))
+ continue;
+
+ err = libbpf_ensure_mem((void **)&res->addrs, &res->cap,
+ sizeof(unsigned long), res->cnt + 1);
+ if (err)
+ return err;
+ res->addrs[res->cnt++] = (unsigned long) sym_addr;
+ return 0;
+}
+
static int libbpf_available_kallsyms_parse(struct kprobe_multi_resolve *res)
{
+ struct avail_kallsyms_data data;
char sym_name[500];
const char *available_functions_file = tracefs_available_filter_functions();
FILE *f;
@@ -10614,42 +10637,13 @@ static int libbpf_available_kallsyms_parse(struct kprobe_multi_resolve *res)
/* sort available functions */
qsort(syms, cnt, sizeof(void *), qsort_compare_function);
- f = fopen("/proc/kallsyms", "r");
- if (!f) {
- err = -errno;
- pr_warn("failed to open /proc/kallsyms\n");
- goto free_syms;
- }
-
- while (true) {
- unsigned long long sym_addr;
-
- ret = fscanf(f, "%llx %*c %499s%*[^\n]\n", &sym_addr, sym_name);
- if (ret == EOF && feof(f))
- break;
-
- if (ret != 2) {
- pr_warn("failed to read kallsyms entry: %d\n", ret);
- err = -EINVAL;
- goto cleanup;
- }
-
- if (!bsearch(&sym_name, syms, cnt, sizeof(void *), bsearch_compare_function))
- continue;
-
- err = libbpf_ensure_mem((void **)&res->addrs, &res->cap,
- sizeof(unsigned long), res->cnt + 1);
- if (err)
- goto cleanup;
-
- res->addrs[res->cnt++] = (unsigned long) sym_addr;
- }
+ data.syms = syms;
+ data.res = res;
+ libbpf_kallsyms_parse(avail_kallsyms_cb, res);
if (!res->cnt)
err = -ENOENT;
-cleanup:
- fclose(f);
free_syms:
for (i = 0; i < cnt; i++)
free((char *)syms[i]);
