1 // SPDX-License-Identifier: GPL-2.0 2 /* 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 10 char _license[] SEC("license") = "GPL"; 11 12 pid_t target_pid; 13 u64 root_cg_id, leaf_cg_id; 14 u64 first_cg_id, last_cg_id; 15 int pre_order_cnt, post_order_cnt, children_cnt, tree_high; 16 17 struct cgroup *bpf_cgroup_from_id(u64 cgid) __ksym; 18 void bpf_cgroup_release(struct cgroup *p) __ksym; 19 void bpf_rcu_read_lock(void) __ksym; 20 void bpf_rcu_read_unlock(void) __ksym; 21 22 SEC("fentry.s/" SYS_PREFIX "sys_getpgid") 23 int iter_css_for_each(const void *ctx) 24 { 25 struct task_struct *cur_task = bpf_get_current_task_btf(); 26 struct cgroup_subsys_state *root_css, *leaf_css, *pos; 27 struct cgroup *root_cgrp, *leaf_cgrp, *cur_cgrp; 28 29 if (cur_task->pid != target_pid) 30 return 0; 31 32 root_cgrp = bpf_cgroup_from_id(root_cg_id); 33 34 if (!root_cgrp) 35 return 0; 36 37 leaf_cgrp = bpf_cgroup_from_id(leaf_cg_id); 38 39 if (!leaf_cgrp) { 40 bpf_cgroup_release(root_cgrp); 41 return 0; 42 } 43 root_css = &root_cgrp->self; 44 leaf_css = &leaf_cgrp->self; 45 pre_order_cnt = post_order_cnt = children_cnt = tree_high = 0; 46 first_cg_id = last_cg_id = 0; 47 48 bpf_rcu_read_lock(); 49 bpf_for_each(css, pos, root_css, BPF_CGROUP_ITER_DESCENDANTS_POST) { 50 cur_cgrp = pos->cgroup; 51 post_order_cnt++; 52 last_cg_id = cur_cgrp->kn->id; 53 } 54 55 bpf_for_each(css, pos, root_css, BPF_CGROUP_ITER_DESCENDANTS_PRE) { 56 cur_cgrp = pos->cgroup; 57 pre_order_cnt++; 58 if (!first_cg_id) 59 first_cg_id = cur_cgrp->kn->id; 60 } 61 62 bpf_for_each(css, pos, root_css, BPF_CGROUP_ITER_CHILDREN) { 63 children_cnt++; 64 } 65 66 bpf_for_each(css, pos, leaf_css, BPF_CGROUP_ITER_ANCESTORS_UP) 67 tree_high++; 68 69 bpf_for_each(css, pos, root_css, BPF_CGROUP_ITER_ANCESTORS_UP) 70 tree_high--; 71 bpf_rcu_read_unlock(); 72 bpf_cgroup_release(root_cgrp); 73 bpf_cgroup_release(leaf_cgrp); 74 return 0; 75 } 76