project(open-hook)
cmake_minimum_required(VERSION 3.4)

add_library(open3-hook SHARED
    open_hook.c)
target_link_libraries(open3-hook -ldl)

// Copyright (c) 2022 Xu Shaohua <shaohua@biofan.org>. All rights reserved.
// Use of this source is governed by General Public License that can be found
// in the LICENSE file.

#define _GNU_SOURCE

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <stdint.h>
#include <stdarg.h>
#include <fcntl.h>
#include <sys/types.h>
#include <unistd.h>
#include <dlfcn.h>

static int g_inited = 0;

typedef int (*open3_fn_t)(const char *path, int flag, int mode);
static open3_fn_t true_open3 = NULL;

static void* load_sym(char* symname) {
  void* funcptr = dlsym(RTLD_NEXT, symname);
  if (!funcptr) {
    fprintf(stderr, "Cannot load symbol '%s' %s\n", symname, dlerror());
    exit(1);
  } else {
    printf("loaded symbol '%s'" " real addr %p\n", symname, funcptr);
  }
  if (funcptr == NULL) {
    fprintf(stderr, "funcptr is null!\n");
    abort();
  }
  return funcptr;
}

static void init_symbols() {
  if (g_inited == 0) {
    write(1, "init_symbols()\n", 16);
    true_open3 = load_sym("open");
    g_inited = 1;
  }
}

static int sys_open(const char* path, int flags, mode_t mode) {
  printf("sys_open()\n");
  return openat(AT_FDCWD, path, flags, mode);
}

int open(const char* path, int flags, ...) {
  printf("open3(%s)\n", path);
  mode_t mode = 0;
  init_symbols();

	if ((flags & O_CREAT) || (flags & O_TMPFILE) == O_TMPFILE) {
		va_list ap;
		va_start(ap, flags);
		mode = va_arg(ap, mode_t);
		va_end(ap);
	}

  return sys_open(path, flags, mode);
  //return true_open3(path, flags, mode);
}

#!/usr/bin/env bash
# leehom Chen clh021@gmail.com
cmake -Bbuild
cmake --build build

#!/usr/bin/env bash
# leehom Chen clh021@gmail.com
export LD_PRELOAD=$(pwd)/build/libopen3-hook.so
# $HOME/Desktop/lithium/lithium https://bing.com
$HOME/Desktop/lithium/lithium-engine \
  -test \
  $HOME/.cache/lithium_runtimes/runtimes/7662198e44f82b9480c2f31b94052fb4/application.ini \
  https://bing.com "{}"