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// SPDX-License-Identifier: GPL-2.0
#include <test_progs.h>
#include <bpf/btf.h>
#define TRACEFS "/sys/kernel/tracing"
#define DEBUGFS_TRACING "/sys/kernel/debug/tracing"
#define EVENT_SUBPATH "events/bpf_testmod/bpf_testmod_test_read/btf_ids"
struct btf_ids_info {
__u32 obj_id;
__u32 raw_id;
__u32 tp_id;
};
static const char *btf_ids_path(char *buf, size_t sz)
{
if (access(TRACEFS "/trace", F_OK) == 0)
snprintf(buf, sz, "%s/%s", TRACEFS, EVENT_SUBPATH);
else
snprintf(buf, sz, "%s/%s", DEBUGFS_TRACING, EVENT_SUBPATH);
return buf;
}
static int read_btf_ids(struct btf_ids_info *info)
{
char path[256], buf[256];
int fd, n;
fd = open(btf_ids_path(path, sizeof(path)), O_RDONLY);
if (fd < 0)
return -errno;
n = read(fd, buf, sizeof(buf) - 1);
close(fd);
if (n <= 0)
return -EIO;
buf[n] = '\0';
if (sscanf(buf,
"btf_obj_id: %u\nraw_btf_id: %u\ntp_btf_id: %u\n",
&info->obj_id, &info->raw_id, &info->tp_id) != 3)
return -EINVAL;
return 0;
}
static const char *param_name(struct btf *btf, const struct btf_param *p)
{
return btf__name_by_offset(btf, p->name_off);
}
static const char *member_name(struct btf *btf, const struct btf_member *m)
{
return btf__name_by_offset(btf, m->name_off);
}
void test_tp_btf_ids(void)
{
const struct btf_type *proto_t, *rec_t;
const struct btf_param *params;
const struct btf_member *members;
struct btf_ids_info info;
struct btf *vmlinux_btf, *btf;
const char *name;
int err;
if (!env.has_testmod) {
test__skip();
return;
}
err = read_btf_ids(&info);
if (!ASSERT_OK(err, "read btf_ids"))
return;
ASSERT_GT(info.obj_id, 0, "obj_id non-zero");
ASSERT_GT(info.raw_id, 0, "raw_id non-zero");
ASSERT_GT(info.tp_id, 0, "tp_id non-zero");
vmlinux_btf = btf__load_vmlinux_btf();
if (!ASSERT_OK_PTR(vmlinux_btf, "load vmlinux BTF"))
return;
/* Module BTF is split BTF; load with vmlinux as base. */
btf = btf__load_from_kernel_by_id_split(info.obj_id, vmlinux_btf);
if (!ASSERT_OK_PTR(btf, "load module BTF")) {
btf__free(vmlinux_btf);
return;
}
/*
* raw_btf_id should be the FUNC_PROTO of __bpf_trace_<call>:
* void *__data, struct task_struct *task,
* struct bpf_testmod_test_read_ctx *ctx
*/
proto_t = btf__type_by_id(btf, info.raw_id);
if (!ASSERT_OK_PTR(proto_t, "raw type_by_id"))
goto out;
if (!ASSERT_TRUE(btf_is_func_proto(proto_t), "raw is FUNC_PROTO"))
goto out;
if (!ASSERT_EQ(btf_vlen(proto_t), 3, "func_proto arg count"))
goto out;
params = btf_params(proto_t);
ASSERT_STREQ(param_name(btf, ¶ms[0]), "__data", "arg0 name");
ASSERT_STREQ(param_name(btf, ¶ms[1]), "task", "arg1 name");
ASSERT_STREQ(param_name(btf, ¶ms[2]), "ctx", "arg2 name");
/*
* tp_btf_id should be STRUCT trace_event_raw_<call> with the
* fields declared by TP_STRUCT__entry plus the common header.
*/
rec_t = btf__type_by_id(btf, info.tp_id);
if (!ASSERT_OK_PTR(rec_t, "tp type_by_id"))
goto out;
if (!ASSERT_TRUE(btf_is_struct(rec_t), "tp is STRUCT"))
goto out;
name = btf__name_by_offset(btf, rec_t->name_off);
ASSERT_STREQ(name, "trace_event_raw_bpf_testmod_test_read",
"tp struct name");
if (!ASSERT_GE(btf_vlen(rec_t), 5, "tp struct field count"))
goto out;
members = btf_members(rec_t);
ASSERT_STREQ(member_name(btf, &members[0]), "ent", "field0 name");
ASSERT_STREQ(member_name(btf, &members[1]), "pid", "field1 name");
ASSERT_STREQ(member_name(btf, &members[2]), "comm", "field2 name");
ASSERT_STREQ(member_name(btf, &members[3]), "off", "field3 name");
ASSERT_STREQ(member_name(btf, &members[4]), "len", "field4 name");
out:
btf__free(btf);
btf__free(vmlinux_btf);
}
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