73 lines · c
1// SPDX-License-Identifier: GPL-2.02/* Copyright (C) 2023 Chuyi Zhou <zhouchuyi@bytedance.com> */3 4#include "vmlinux.h"5#include <bpf/bpf_helpers.h>6#include <bpf/bpf_tracing.h>7#include "bpf_misc.h"8#include "bpf_experimental.h"9 10char _license[] SEC("license") = "GPL";11 12pid_t target_pid;13u64 root_cg_id, leaf_cg_id;14u64 first_cg_id, last_cg_id;15 16int pre_order_cnt, post_order_cnt, tree_high;17 18struct cgroup *bpf_cgroup_from_id(u64 cgid) __ksym;19void bpf_cgroup_release(struct cgroup *p) __ksym;20void bpf_rcu_read_lock(void) __ksym;21void bpf_rcu_read_unlock(void) __ksym;22 23SEC("fentry.s/" SYS_PREFIX "sys_getpgid")24int iter_css_for_each(const void *ctx)25{26 struct task_struct *cur_task = bpf_get_current_task_btf();27 struct cgroup_subsys_state *root_css, *leaf_css, *pos;28 struct cgroup *root_cgrp, *leaf_cgrp, *cur_cgrp;29 30 if (cur_task->pid != target_pid)31 return 0;32 33 root_cgrp = bpf_cgroup_from_id(root_cg_id);34 35 if (!root_cgrp)36 return 0;37 38 leaf_cgrp = bpf_cgroup_from_id(leaf_cg_id);39 40 if (!leaf_cgrp) {41 bpf_cgroup_release(root_cgrp);42 return 0;43 }44 root_css = &root_cgrp->self;45 leaf_css = &leaf_cgrp->self;46 pre_order_cnt = post_order_cnt = tree_high = 0;47 first_cg_id = last_cg_id = 0;48 49 bpf_rcu_read_lock();50 bpf_for_each(css, pos, root_css, BPF_CGROUP_ITER_DESCENDANTS_POST) {51 cur_cgrp = pos->cgroup;52 post_order_cnt++;53 last_cg_id = cur_cgrp->kn->id;54 }55 56 bpf_for_each(css, pos, root_css, BPF_CGROUP_ITER_DESCENDANTS_PRE) {57 cur_cgrp = pos->cgroup;58 pre_order_cnt++;59 if (!first_cg_id)60 first_cg_id = cur_cgrp->kn->id;61 }62 63 bpf_for_each(css, pos, leaf_css, BPF_CGROUP_ITER_ANCESTORS_UP)64 tree_high++;65 66 bpf_for_each(css, pos, root_css, BPF_CGROUP_ITER_ANCESTORS_UP)67 tree_high--;68 bpf_rcu_read_unlock();69 bpf_cgroup_release(root_cgrp);70 bpf_cgroup_release(leaf_cgrp);71 return 0;72}73