40 lines
693 B
C
40 lines
693 B
C
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/* SPDX-License-Identifier: GPL-2.0 */
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/* Copyright (c) 2021 Hengqi Chen */
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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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const volatile pid_t my_pid = 0;
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int value = 0;
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SEC("raw_tp/sys_enter")
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int tailcall_1(void *ctx)
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{
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value = 42;
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return 0;
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}
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struct {
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__uint(type, BPF_MAP_TYPE_PROG_ARRAY);
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__uint(max_entries, 2);
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__uint(key_size, sizeof(__u32));
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__array(values, int (void *));
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} prog_array_init SEC(".maps") = {
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.values = {
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[1] = (void *)&tailcall_1,
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},
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};
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SEC("raw_tp/sys_enter")
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int entry(void *ctx)
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{
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pid_t pid = bpf_get_current_pid_tgid() >> 32;
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if (pid != my_pid)
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return 0;
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bpf_tail_call(ctx, &prog_array_init, 1);
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return 0;
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}
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