Compile Once, Run Everywhere(CO-RE)

    LIBBPF_OPTS(bpf_object_open_opts , opts,
    );
    LIBBPF_OPTS(bpf_uprobe_opts, uprobe_opts);
    if (argc != 3 && argc != 2) {
        fprintf(stderr, "Usage: %s <example-name> [<external-btf>]\n", argv[0]);
        return 1;
    }
    if (argc == 3)
        opts.btf_custom_path = argv[2];
 
    /* Set up libbpf errors and debug info callback */
    libbpf_set_print(libbpf_print_fn);
 
    /* Cleaner handling of Ctrl-C */
    signal(SIGINT, sig_handler);
    signal(SIGTERM, sig_handler);
 
    /* Load and verify BPF application */
    skel = uprobe_bpf__open_opts(&opts);
    if (!skel) {
        fprintf(stderr, "Failed to open and load BPF skeleton\n");
        return 1;
    }

#define BPF_NO_GLOBAL_DATA
// #define BPF_NO_PRESERVE_ACCESS_INDEX
#include <vmlinux.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>
 
#ifndef BPF_NO_PRESERVE_ACCESS_INDEX
#pragma clang attribute push (__attribute__((preserve_access_index)), apply_to = record)
#endif
 
struct data {
        int a;
        int c;
        int d;
};
 
#ifndef BPF_NO_PRESERVE_ACCESS_INDEX
#pragma clang attribute pop
#endif
 
 
SEC("uprobe/examples/btf-base:add_test")
int BPF_UPROBE(add_test, struct data *d)
{
    int a = 0, c = 0;
    bpf_probe_read_user(&a, sizeof(a), &d->a);
    bpf_probe_read_user(&c, sizeof(c), &d->c);
    bpf_printk("add_test(&d) %d + %d = %d\n", a, c,  a + c);
    return a + c;
}
 
char LICENSE[] SEC("license") = "Dual BSD/GPL";