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