#include <stdlib.h>
#include <stdint.h>
#include <stdio.h>
#include <fcntl.h>
#include <sys/syscall.h>
#include <unistd.h>
#include <stdbool.h>

void crimes_startup_run(uint8_t* frame) {
    // we trash argv up to hack on ld.so arguments without needing malloc
    // this is pad space to catch that and not explode uwu
    volatile char _pad[(sizeof(char*) * 4)];

    // XXX: assumes stack goes up
    // big weh
    size_t argc = *((size_t*) (frame + sizeof(size_t)));
    char** argv = ((char**) (frame + sizeof(size_t) + sizeof(char*)));
    char** envp = argv + argc + 1;

    // fake usage of _pad
    // also a barrier to ensure argc gets read
    asm volatile("" :: "rm"(_pad) : "memory");

    syscall(SYS_write, STDOUT_FILENO, "[crimes] detect maps\n", 21);

    int fd = syscall(SYS_open, "/proc/self/maps", O_RDONLY);
    if (fd < 0) {
        syscall(SYS_write, STDOUT_FILENO, "[crimes] open failed\n", 21);
        syscall(SYS_exit, -1);
    }
    char buf[32];
    int state = 0;
    while (true) {
        ssize_t res = syscall(SYS_read, fd, buf, sizeof(buf));
        if (res == 0) {
            break;
        } else if (res < 0) {
            syscall(SYS_write, STDOUT_FILENO, "[crimes] read error\n", 20);
            syscall(SYS_exit, -1);
        }

        for (ssize_t i = 0; i < res; i++) {
            switch (state) {
                case 0:
                    if (buf[i] == '/') { state++; }
                    else { state = 0; }
                    break;
                case 1:
                    if (buf[i] == 'l') { state++; }
                    else { state = 0; }
                    break;
                case 2:
                    if (buf[i] == 'd') { state++; }
                    else { state = 0; }
                    break;
                case 3:
                    if (buf[i] == '-') { state++; }
                    else { state = 0; }
                    break;
                default:
                    break;
            }
            if (state > 3) {
                break;
            }
        }
        if (state > 3) {
            break;
        }
    }

    if (state > 3) {
        syscall(SYS_write, STDOUT_FILENO, "[crimes] detected libc. going back to startup\n", 46);
        return;
    }

    syscall(SYS_write, STDOUT_FILENO, "[crimes] running ld.so\n", 23);

    // XXX: currently we hardcode the glibc parameters
    // detect glibc or musl at runtime and load the appropriate params
    char* ld = "/usr/lib/ld-2.32.so";
    char* pl = "--preload";
    char* ldlp =
        "/usr/lib/libm.so.6:/usr/lib/libpthread.so.0:/usr/lib/libdl.so.2:/usr/lib/libc.so.6";
    uintptr_t args[4 + argc];
    args[0] = (uintptr_t)ld;
    args[1] = (uintptr_t)pl;
    args[2] = (uintptr_t)ldlp;

    for (size_t i = 0; i < argc; i++) {
        args[3 + i] = (uintptr_t) argv[i];
    }

    args[3 + argc] = 0;

    syscall(SYS_execve, ld, args, envp);

    syscall(SYS_write, STDOUT_FILENO, "[crimes] exec failed!\n", 22);
    syscall(SYS_exit, -1);
}