#include <sys/stat.h>
#include <fcntl.h>
#include <elf.h>
#include <string.h>
#include "file.h"
#include "pk.h"

long load_elf(const char* fn, int* user64)
{
  sysret_t ret = file_open(fn, strlen(fn)+1, O_RDONLY, 0);
  file_t* file = (file_t*)ret.result;
  if(file == NULL)
    panic("couldn't open %s!", fn);

  char buf[2048]; // XXX
  int header_size = file_read(file, buf, sizeof(buf)).result;
  kassert(header_size >= (int)sizeof(Elf64_Ehdr));

  const Elf64_Ehdr* eh64 = (const Elf64_Ehdr*)buf;
  kassert(eh64->e_ident[0] == '\177' && eh64->e_ident[1] == 'E' &&
          eh64->e_ident[2] == 'L'    && eh64->e_ident[3] == 'F');

  #define LOAD_ELF do { \
    eh = (typeof(eh))buf; \
    kassert(header_size >= eh->e_phoff + eh->e_phnum*sizeof(*ph)); \
    ph = (typeof(ph))(buf+eh->e_phoff); \
    for(int i = 0; i < eh->e_phnum; i++, ph++) { \
      if(ph->p_type == SHT_PROGBITS && ph->p_memsz) { \
        kassert(file_pread(file, (char*)(long)ph->p_vaddr, ph->p_filesz, ph->p_offset).result == ph->p_filesz); \
        memset((char*)(long)ph->p_vaddr+ph->p_filesz, 0, ph->p_memsz-ph->p_filesz); \
      } \
    } \
  } while(0)

  long entry;
  if(eh64->e_ident[EI_CLASS] == ELFCLASS32)
  {
    Elf32_Ehdr* eh;
    Elf32_Phdr* ph;
    LOAD_ELF;
    entry = eh->e_entry;
  }
  else
  {
    kassert(eh64->e_ident[EI_CLASS] == ELFCLASS64);
    Elf64_Ehdr* eh;
    Elf64_Phdr* ph;
    LOAD_ELF;
    entry = eh->e_entry;
  }

  *user64 = eh64->e_ident[EI_CLASS] == ELFCLASS64;

  file_decref(file);

  return entry;
}