// SPDX-License-Identifier: GPL-2.0 /* Copyright (C) 2023 Chuyi Zhou <zhouchuyi@bytedance.com> */ #include "vmlinux.h" #include <bpf/bpf_helpers.h> #include <bpf/bpf_tracing.h> #include "bpf_misc.h" #include "bpf_experimental.h" char _license[] SEC("license") = "GPL"; pid_t target_pid; u64 root_cg_id, leaf_cg_id; u64 first_cg_id, last_cg_id; int pre_order_cnt, post_order_cnt, tree_high; struct cgroup *bpf_cgroup_from_id(u64 cgid) __ksym; void bpf_cgroup_release(struct cgroup *p) __ksym; void bpf_rcu_read_lock(void) __ksym; void bpf_rcu_read_unlock(void) __ksym; SEC("fentry.s/" SYS_PREFIX "sys_getpgid") int iter_css_for_each(const void *ctx) { struct task_struct *cur_task = bpf_get_current_task_btf(); struct cgroup_subsys_state *root_css, *leaf_css, *pos; struct cgroup *root_cgrp, *leaf_cgrp, *cur_cgrp; if (cur_task->pid != target_pid) return 0; root_cgrp = bpf_cgroup_from_id(root_cg_id); if (!root_cgrp) return 0; leaf_cgrp = bpf_cgroup_from_id(leaf_cg_id); if (!leaf_cgrp) { bpf_cgroup_release(root_cgrp); return 0; } root_css = &root_cgrp->self; leaf_css = &leaf_cgrp->self; pre_order_cnt = post_order_cnt = tree_high = 0; first_cg_id = last_cg_id = 0; bpf_rcu_read_lock(); bpf_for_each(css, pos, root_css, BPF_CGROUP_ITER_DESCENDANTS_POST) { cur_cgrp = pos->cgroup; post_order_cnt++; last_cg_id = cur_cgrp->kn->id; } bpf_for_each(css, pos, root_css, BPF_CGROUP_ITER_DESCENDANTS_PRE) { cur_cgrp = pos->cgroup; pre_order_cnt++; if (!first_cg_id) first_cg_id = cur_cgrp->kn->id; } bpf_for_each(css, pos, leaf_css, BPF_CGROUP_ITER_ANCESTORS_UP) tree_high++; bpf_for_each(css, pos, root_css, BPF_CGROUP_ITER_ANCESTORS_UP) tree_high--; bpf_rcu_read_unlock(); bpf_cgroup_release(root_cgrp); bpf_cgroup_release(leaf_cgrp); return 0; }