On 6/19/25 08:34, Eduard Zingerman wrote:
On Wed, 2025-06-18 at 21:39 +0100, Mykyta Yatsenko wrote:
From: Mykyta Yatsenko <yatsenko@xxxxxxxx>
Implement support for presetting values for array elements in veristat.
For example:
```
sudo ./veristat set_global_vars.bpf.o -G "arr[3] = 1"
```
Arrays of structures and structure of arrays work, but each individual
scalar value has to be set separately: `foo[1].bar[2] = value`.
Signed-off-by: Mykyta Yatsenko <yatsenko@xxxxxxxx>
---
tools/testing/selftests/bpf/veristat.c | 226 ++++++++++++++++++++-----
1 file changed, 180 insertions(+), 46 deletions(-)
diff --git a/tools/testing/selftests/bpf/veristat.c b/tools/testing/selftests/bpf/veristat.c
index 483442c08ecf..9942adbda411 100644
--- a/tools/testing/selftests/bpf/veristat.c
+++ b/tools/testing/selftests/bpf/veristat.c
Acked-by: Eduard Zingerman <eddyz87@xxxxxxxxx>
[...]
@@ -1670,7 +1706,7 @@ static int append_var_preset(struct var_preset **presets, int *cnt, const char *
memset(cur, 0, sizeof(*cur));
(*cnt)++;
- if (sscanf(expr, "%s = %s %n", var, val, &n) != 2 || n != strlen(expr)) {
+ if (sscanf(expr, "%[][a-zA-Z0-9_.] = %s %n", var, val, &n) != 2 || n != strlen(expr)) {
Out of curiosity, won't match if the pattern would remain "%s = %s %n"?
"foo=1" won't be parsed correctly, as the entire string will be consumed
by the first %s.
fprintf(stderr, "Failed to parse expression '%s'\n", expr);
return -EINVAL;
}
@@ -1763,17 +1799,103 @@ static bool is_preset_supported(const struct btf_type *t)
return btf_is_int(t) || btf_is_enum(t) || btf_is_enum64(t);
}
+static int find_enum_value(const struct btf *btf, const char *name, long long *value)
+{
+ const struct btf_type *t;
+ int cnt, i;
+ long long lvalue;
+
+ cnt = btf__type_cnt(btf);
+ for (i = 1; i != cnt; ++i) {
+ t = btf__type_by_id(btf, i);
+
+ if (!btf_is_any_enum(t))
+ continue;
+
+ if (enum_value_from_name(btf, t, name, &lvalue) == 0) {
+ *value = lvalue;
+ return 0;
+ }
+ }
+ return -ESRCH;
+}
+
[...]
@@ -1815,26 +1938,29 @@ const int btf_find_member(const struct btf *btf,
static int adjust_var_secinfo(struct btf *btf, const struct btf_type *t,
struct btf_var_secinfo *sinfo, struct var_preset *preset)
{
- const struct btf_type *base_type, *member_type;
- int err, member_tid, i;
- __u32 member_offset = 0;
-
- base_type = btf__type_by_id(btf, btf__resolve_type(btf, t->type));
-
- for (i = 1; i < preset->atom_count; ++i) {
- err = btf_find_member(btf, base_type, 0, preset->atoms[i].name,
- &member_tid, &member_offset);
- if (err) {
- fprintf(stderr, "Could not find member %s for variable %s\n",
- preset->atoms[i].name, preset->atoms[i - 1].name);
- return err;
+ const struct btf_type *base_type;
+ int err, i = 1, n;
+ int tid;
+
+ tid = btf__resolve_type(btf, t->type);
+ base_type = btf__type_by_id(btf, tid);
+
+ while (i < preset->atom_count) {
+ if (preset->atoms[i].type == ARRAY_INDEX) {
+ n = adjust_var_secinfo_array(btf, tid, preset, i, sinfo);
+ if (n < 0)
+ return n;
+ i += n;
Having a nested loop to consume all indices looks annoying.
On the other hand, there is not much one can do w/o some kind of
btf__type_physical_size.
+ } else {
+ err = btf_find_member(btf, base_type, 0, preset->atoms[i].name, sinfo);
+ if (err)
+ return err;
+ i++;
}
- member_type = btf__type_by_id(btf, member_tid);
- sinfo->offset += member_offset / 8;
- sinfo->size = member_type->size;
- sinfo->type = member_tid;
- base_type = member_type;
+ base_type = btf__type_by_id(btf, sinfo->type);
+ tid = sinfo->type;
}
+
return 0;
}
[...]
