#include "vmlinux.h"
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>
#include <bpf/bpf_core_read.h>
#include "event.h"

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

struct
{
    __uint(type, BPF_MAP_TYPE_RINGBUF);
    __uint(max_entries, 1 << 24);
} events SEC(".maps");


const char is_libcuda_needle[] = "libcuda";
static int is_libcuda(const char *p)
{
#pragma unroll
    for (int i = 0; i < MAX_PATH - sizeof(is_libcuda_needle) - 1; i++)
    {
        int match = 1;
#pragma unroll
        for (int j = 0; j < sizeof(is_libcuda_needle) - 1; j++)
        {
            if (p[i + j] != is_libcuda_needle[j])
            {
                match = 0;
                break;
            }
        }
        if (match)
            return 1;
    }
    return 0;
}

const char is_libnv_needle[] = "libnv";
static int is_libnv(const char *p)
{
#pragma unroll
    for (int i = 0; i < MAX_PATH - sizeof(is_libnv_needle) - 1; i++)
    {
        int match = 1;
#pragma unroll
        for (int j = 0; j < sizeof(is_libnv_needle) - 1; j++)
        {
            if (p[i + j] != is_libnv_needle[j])
            {
                match = 0;
                break;
            }
        }
        if (match)
            return 1;
    }
    return 0;
}

SEC("tracepoint/syscalls/sys_enter_openat")
int trace_openat(struct trace_event_raw_sys_enter *ctx)
{
    const char *filename = (const char *)BPF_CORE_READ(ctx, args[1]);

    char path[MAX_PATH];
    if (bpf_probe_read_user_str(path, sizeof(path), filename) < 0)
        return 0;

    if (!is_libcuda(path) && !is_libnv(path))
        return 0;

    struct event *e = bpf_ringbuf_reserve(&events, sizeof(*e), 0);
    if (!e)
        return 0;

    __builtin_memcpy(e->path, path, sizeof(path));

    e->pid = bpf_get_current_pid_tgid() >> 32;
    bpf_get_current_comm(&e->comm, sizeof(e->comm));
    e->op = OPEN;
    e->size = 0;

    bpf_ringbuf_submit(e, 0);
    return 0;
}

SEC("tracepoint/syscalls/sys_enter_mmap")
int trace_mmap(struct trace_event_raw_sys_enter *ctx)
{

    struct event *e = bpf_ringbuf_reserve(&events, sizeof(*e), 0);
    if (!e)
        return 0;
    e->pid = bpf_get_current_pid_tgid() >> 32;
    bpf_get_current_comm(&e->comm, sizeof(e->comm));

    e->op = MMAP;
    e->size = BPF_CORE_READ(ctx, args[1]); // length
    e->path[0] = 0;

    bpf_ringbuf_submit(e, 0);
    return 0;
}

SEC("tracepoint/syscalls/sys_enter_munmap")
int trace_munmap(struct trace_event_raw_sys_enter *ctx)
{

    struct event *e = bpf_ringbuf_reserve(&events, sizeof(*e), 0);
    if (!e)
        return 0;

    e->pid = bpf_get_current_pid_tgid() >> 32;
    bpf_get_current_comm(&e->comm, sizeof(e->comm));

    e->op = MUNMAP;
    e->size = BPF_CORE_READ(ctx, args[1]); // length
    e->path[0] = 0;

    bpf_ringbuf_submit(e, 0);
    return 0;
}