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selftests/bpf: Support struct/union presets in veristat

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Extend commit e3c9abd0d1 ("selftests/bpf: Implement setting global
variables in veristat") to support applying presets to members of
the global structs or unions in veristat.
For example:
```
./veristat set_global_vars.bpf.o  -G "union1.struct3.var_u8_h = 0xBB"
```

Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20250408104544.140317-1-mykyta.yatsenko5@gmail.com
This commit is contained in:
Mykyta Yatsenko
2025-04-09 16:16:12 -07:00
committed by Andrii Nakryiko
parent c966139485
commit 37b1b3ed20
4 changed files with 140 additions and 8 deletions
Download Patch File Download Diff File Expand all files Collapse all files
tools/testing/selftests/bpf/prog_tests/test_veristat.c
+5
View File
@@ -63,6 +63,9 @@ static void test_set_global_vars_succeeds(void)
" -G \"var_eb = EB2\" "\
" -G \"var_ec = EC2\" "\
" -G \"var_b = 1\" "\
" -G \"struct1.struct2.u.var_u8 = 170\" "\
" -G \"union1.struct3.var_u8_l = 0xaa\" "\
" -G \"union1.struct3.var_u8_h = 0xaa\" "\
"-vl2 > %s", fix->veristat, fix->tmpfile);
read(fix->fd, fix->output, fix->sz);
@@ -78,6 +81,8 @@ static void test_set_global_vars_succeeds(void)
__CHECK_STR("_w=12 ", "var_eb = EB2");
__CHECK_STR("_w=13 ", "var_ec = EC2");
__CHECK_STR("_w=1 ", "var_b = 1");
__CHECK_STR("_w=170 ", "struct1.struct2.u.var_u8 = 170");
__CHECK_STR("_w=0xaaaa ", "union1.var_u16 = 0xaaaa");
out:
teardown_fixture(fix);
tools/testing/selftests/bpf/progs/prepare.c
-1
View File
@@ -2,7 +2,6 @@
/* Copyright (c) 2025 Meta */
#include <vmlinux.h>
#include <bpf/bpf_helpers.h>
//#include <bpf/bpf_tracing.h>
char _license[] SEC("license") = "GPL";
tools/testing/selftests/bpf/progs/set_global_vars.c
+41
View File
@@ -24,6 +24,44 @@ const volatile enum Enumu64 var_eb = EB1;
const volatile enum Enums64 var_ec = EC1;
const volatile bool var_b = false;
struct Struct {
int:16;
__u16 filler;
struct {
const __u16 filler2;
};
struct Struct2 {
__u16 filler;
volatile struct {
const int:1;
union {
const volatile __u8 var_u8;
const volatile __s16 filler3;
const int:1;
} u;
};
} struct2;
};
const volatile __u32 stru = 0; /* same prefix as below */
const volatile struct Struct struct1 = {.struct2 = {.u = {.var_u8 = 1}}};
union Union {
__u16 var_u16;
struct Struct3 {
struct {
__u8 var_u8_l;
};
struct {
struct {
__u8 var_u8_h;
};
};
} struct3;
};
const volatile union Union union1 = {.var_u16 = -1};
char arr[4] = {0};
SEC("socket")
@@ -43,5 +81,8 @@ int test_set_globals(void *ctx)
a = var_eb;
a = var_ec;
a = var_b;
a = struct1.struct2.u.var_u8;
a = union1.var_u16;
return a;
}
tools/testing/selftests/bpf/veristat.c
+94 -7
View File
@@ -1486,7 +1486,84 @@ 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 set_global_var(struct bpf_object *obj, struct btf *btf, const struct btf_type *t,
const int btf_find_member(const struct btf *btf,
const struct btf_type *parent_type,
__u32 parent_offset,
const char *member_name,
int *member_tid,
__u32 *member_offset)
{
int i;
if (!btf_is_composite(parent_type))
return -EINVAL;
for (i = 0; i < btf_vlen(parent_type); ++i) {
const struct btf_member *member;
const struct btf_type *member_type;
int tid;
member = btf_members(parent_type) + i;
tid = btf__resolve_type(btf, member->type);
if (tid < 0)
return -EINVAL;
member_type = btf__type_by_id(btf, tid);
if (member->name_off) {
const char *name = btf__name_by_offset(btf, member->name_off);
if (strcmp(member_name, name) == 0) {
if (btf_member_bitfield_size(parent_type, i) != 0) {
fprintf(stderr, "Bitfield presets are not supported %s\n",
name);
return -EINVAL;
}
*member_offset = parent_offset + member->offset;
*member_tid = tid;
return 0;
}
} else if (btf_is_composite(member_type)) {
int err;
err = btf_find_member(btf, member_type, parent_offset + member->offset,
member_name, member_tid, member_offset);
if (!err)
return 0;
}
}
return -EINVAL;
}
static int adjust_var_secinfo(struct btf *btf, const struct btf_type *t,
struct btf_var_secinfo *sinfo, const char *var)
{
char expr[256], *saveptr;
const struct btf_type *base_type, *member_type;
int err, member_tid;
char *name;
__u32 member_offset = 0;
base_type = btf__type_by_id(btf, btf__resolve_type(btf, t->type));
snprintf(expr, sizeof(expr), "%s", var);
strtok_r(expr, ".", &saveptr);
while ((name = strtok_r(NULL, ".", &saveptr))) {
err = btf_find_member(btf, base_type, 0, name, &member_tid, &member_offset);
if (err) {
fprintf(stderr, "Could not find member %s for variable %s\n", name, var);
return err;
}
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;
}
return 0;
}
static int set_global_var(struct bpf_object *obj, struct btf *btf,
struct bpf_map *map, struct btf_var_secinfo *sinfo,
struct var_preset *preset)
{
@@ -1495,9 +1572,9 @@ static int set_global_var(struct bpf_object *obj, struct btf *btf, const struct
long long value = preset->ivalue;
size_t size;
base_type = btf__type_by_id(btf, btf__resolve_type(btf, t->type));
base_type = btf__type_by_id(btf, btf__resolve_type(btf, sinfo->type));
if (!base_type) {
fprintf(stderr, "Failed to resolve type %d\n", t->type);
fprintf(stderr, "Failed to resolve type %d\n", sinfo->type);
return -EINVAL;
}
if (!is_preset_supported(base_type)) {
@@ -1530,7 +1607,7 @@ static int set_global_var(struct bpf_object *obj, struct btf *btf, const struct
if (value >= max_val || value < -max_val) {
fprintf(stderr,
"Variable %s value %lld is out of range [%lld; %lld]\n",
btf__name_by_offset(btf, t->name_off), value,
btf__name_by_offset(btf, base_type->name_off), value,
is_signed ? -max_val : 0, max_val - 1);
return -EINVAL;
}
@@ -1583,14 +1660,20 @@ static int set_global_vars(struct bpf_object *obj, struct var_preset *presets, i
for (j = 0; j < n; ++j, ++sinfo) {
const struct btf_type *var_type = btf__type_by_id(btf, sinfo->type);
const char *var_name;
int var_len;
if (!btf_is_var(var_type))
continue;
var_name = btf__name_by_offset(btf, var_type->name_off);
var_len = strlen(var_name);
for (k = 0; k < npresets; ++k) {
if (strcmp(var_name, presets[k].name) != 0)
struct btf_var_secinfo tmp_sinfo;
if (strncmp(var_name, presets[k].name, var_len) != 0 ||
(presets[k].name[var_len] != '\0' &&
presets[k].name[var_len] != '.'))
continue;
if (presets[k].applied) {
@@ -1598,13 +1681,17 @@ static int set_global_vars(struct bpf_object *obj, struct var_preset *presets, i
var_name);
return -EINVAL;
}
tmp_sinfo = *sinfo;
err = adjust_var_secinfo(btf, var_type,
&tmp_sinfo, presets[k].name);
if (err)
return err;
err = set_global_var(obj, btf, var_type, map, sinfo, presets + k);
err = set_global_var(obj, btf, map, &tmp_sinfo, presets + k);
if (err)
return err;
presets[k].applied = true;
break;
}
}
}