python-bpf/tests/c-form/ex4.bpf.c

#include <linux/bpf.h>
#include <bpf/bpf_helpers.h>

#define u64 unsigned long long

// Define the map
struct {
    __uint(type, BPF_MAP_TYPE_HASH);
    __type(key, u64);
    __type(value, u64);
    __uint(max_entries, 1);
} last SEC(".maps");

// Handler for syscall entry
SEC("tracepoint/syscalls/sys_enter_execve")
int hello(void *ctx) {
    bpf_printk("entered");
    bpf_printk("multi constant support");
    return 0;
}

// Handler for syscall exit
SEC("tracepoint/syscalls/sys_exit_execve")
long hello_again(void *ctx) {
    bpf_printk("exited");

    // Create a key for map lookup
    u64 key = 0;

    // Simple lookup without conditionals
    u64 *tsp = bpf_map_lookup_elem(&last, &key);
    if (tsp != NULL) {
        u64 delta = bpf_ktime_get_ns() - *tsp;
        if (delta < 1000000000) {
            // output if time is less than 1 second
            bpf_printk("execve called within last second");
        }
        bpf_map_delete_elem(&last, &key);
    }
    // Get current timestamp
    u64 ts = bpf_ktime_get_ns();
    bpf_map_update_elem(&last, &key, &ts, BPF_ANY);
    return 0;
}

char LICENSE[] SEC("license") = "GPL";