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