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// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
#include "vmlinux.h"
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>
char _license[] SEC("license") = "GPL";
struct {
__uint(type, BPF_MAP_TYPE_CGRP_STORAGE);
__uint(map_flags, BPF_F_NO_PREALLOC);
__type(key, int);
__type(value, long);
} map_a SEC(".maps");
struct {
__uint(type, BPF_MAP_TYPE_CGRP_STORAGE);
__uint(map_flags, BPF_F_NO_PREALLOC);
__type(key, int);
__type(value, long);
} map_b SEC(".maps");
#define MAGIC_VALUE 0xabcd1234
pid_t target_pid = 0;
int mismatch_cnt = 0;
int enter_cnt = 0;
int exit_cnt = 0;
int target_hid = 0;
bool is_cgroup1 = 0;
struct cgroup *bpf_task_get_cgroup1(struct task_struct *task, int hierarchy_id) __ksym;
void bpf_cgroup_release(struct cgroup *cgrp) __ksym;
static void __on_enter(struct pt_regs *regs, long id, struct cgroup *cgrp)
{
long *ptr;
int err;
/* populate value 0 */
ptr = bpf_cgrp_storage_get(&map_a, cgrp, 0,
BPF_LOCAL_STORAGE_GET_F_CREATE);
if (!ptr)
return;
/* delete value 0 */
err = bpf_cgrp_storage_delete(&map_a, cgrp);
if (err)
return;
/* value is not available */
ptr = bpf_cgrp_storage_get(&map_a, cgrp, 0, 0);
if (ptr)
return;
/* re-populate the value */
ptr = bpf_cgrp_storage_get(&map_a, cgrp, 0,
BPF_LOCAL_STORAGE_GET_F_CREATE);
if (!ptr)
return;
__sync_fetch_and_add(&enter_cnt, 1);
*ptr = MAGIC_VALUE + enter_cnt;
}
SEC("tp_btf/sys_enter")
int BPF_PROG(on_enter, struct pt_regs *regs, long id)
{
struct task_struct *task;
struct cgroup *cgrp;
task = bpf_get_current_task_btf();
if (task->pid != target_pid)
return 0;
if (is_cgroup1) {
cgrp = bpf_task_get_cgroup1(task, target_hid);
if (!cgrp)
return 0;
__on_enter(regs, id, cgrp);
bpf_cgroup_release(cgrp);
return 0;
}
__on_enter(regs, id, task->cgroups->dfl_cgrp);
return 0;
}
static void __on_exit(struct pt_regs *regs, long id, struct cgroup *cgrp)
{
long *ptr;
ptr = bpf_cgrp_storage_get(&map_a, cgrp, 0,
BPF_LOCAL_STORAGE_GET_F_CREATE);
if (!ptr)
return;
__sync_fetch_and_add(&exit_cnt, 1);
if (*ptr != MAGIC_VALUE + exit_cnt)
__sync_fetch_and_add(&mismatch_cnt, 1);
}
SEC("tp_btf/sys_exit")
int BPF_PROG(on_exit, struct pt_regs *regs, long id)
{
struct task_struct *task;
struct cgroup *cgrp;
task = bpf_get_current_task_btf();
if (task->pid != target_pid)
return 0;
if (is_cgroup1) {
cgrp = bpf_task_get_cgroup1(task, target_hid);
if (!cgrp)
return 0;
__on_exit(regs, id, cgrp);
bpf_cgroup_release(cgrp);
return 0;
}
__on_exit(regs, id, task->cgroups->dfl_cgrp);
return 0;
}
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