#define _GNU_SOURCE
#include <dlfcn.h>
#include <fcntl.h>
#include <stdio.h>

static int teefd = -1;
static int is_tty = -1;
static size_t (*read_original)(int, void *, size_t);

static char fname_buf[200];

__attribute__((constructor))
void ctor(void)
{

  sprintf(fname_buf, "/tmp/log-more-stdin-%d.log", getpid());

    teefd = open(
        fname_buf,
        O_CREAT|O_WRONLY|O_TRUNC, 0666);

    // resolve symbol read
    read_original = dlsym(RTLD_NEXT, "read");

    /* char *newargv[] = { "vendor/log-more-logger.rb", "hello", "world", NULL }; */
    char *newenviron[] = { NULL };
    int pid = fork();
    if(pid == 0) {
      int r = execle("vendor/log-more-logger.rb", "log-more-logger.rb",
          NULL, newenviron);
    }
}

size_t read(int fd, void *buffer, size_t size)
{
    // invoke original read(...)
    size_t count = read_original(fd, buffer, size);

    // if fd is STDIN and teefd is open, echo input
    if(fd == 0 && teefd != -1 && isatty(fd))
    {
        write(teefd, buffer, count);
        /* fsync(teefd); */
    }

    // return result of read_original(...)
    return count;
}