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// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2025 Meta Platforms, Inc. and affiliates. */
#include <vmlinux.h>
#include <bpf/bpf_tracing.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_core_read.h>
#include "bpf_experimental.h"
char _license[] SEC("license") = "GPL";
pid_t target_pid = 0;
char xattr_value[64];
static const char expected_value_a[] = "bpf_selftest_value_a";
static const char expected_value_b[] = "bpf_selftest_value_b";
bool found_value_a;
bool found_value_b;
SEC("lsm.s/file_open")
int BPF_PROG(test_file_open)
{
u64 cgrp_id = bpf_get_current_cgroup_id();
struct cgroup_subsys_state *css, *tmp;
struct bpf_dynptr value_ptr;
struct cgroup *cgrp;
if ((bpf_get_current_pid_tgid() >> 32) != target_pid)
return 0;
bpf_rcu_read_lock();
cgrp = bpf_cgroup_from_id(cgrp_id);
if (!cgrp) {
bpf_rcu_read_unlock();
return 0;
}
css = &cgrp->self;
bpf_dynptr_from_mem(xattr_value, sizeof(xattr_value), 0, &value_ptr);
bpf_for_each(css, tmp, css, BPF_CGROUP_ITER_ANCESTORS_UP) {
int ret;
ret = bpf_cgroup_read_xattr(tmp->cgroup, "user.bpf_test",
&value_ptr);
if (ret < 0)
continue;
if (ret == sizeof(expected_value_a) &&
!bpf_strncmp(xattr_value, sizeof(expected_value_a), expected_value_a))
found_value_a = true;
if (ret == sizeof(expected_value_b) &&
!bpf_strncmp(xattr_value, sizeof(expected_value_b), expected_value_b))
found_value_b = true;
}
bpf_rcu_read_unlock();
bpf_cgroup_release(cgrp);
return 0;
}
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