#include "pwf.h"
#include <pthread.h>

#define FIX(x) (gr->gr_##x = gr->gr_##x - line + buf)

static int getgr_r(const char* name,
                   gid_t gid,
                   struct group* gr,
                   char* buf,
                   size_t size,
                   struct group** res) {
  char* line = 0;
  size_t len = 0;
  char** mem = 0;
  size_t nmem = 0;
  int rv = 0;
  size_t i;
  int cs;

  pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);

  rv = __getgr_a(name, gid, gr, &line, &len, &mem, &nmem, res);
  if (*res && size < len + (nmem + 1) * sizeof(char*) + 32) {
    *res = 0;
    rv = ERANGE;
  }
  if (*res) {
    buf += (16 - (uintptr_t)buf) % 16;
    gr->gr_mem = (void*)buf;
    buf += (nmem + 1) * sizeof(char*);
    memcpy(buf, line, len);
    FIX(name);
    FIX(passwd);
    for (i = 0; mem[i]; i++)
      gr->gr_mem[i] = mem[i] - line + buf;
    gr->gr_mem[i] = 0;
  }
  free(mem);
  free(line);
  pthread_setcancelstate(cs, 0);
  return rv;
}

int getgrnam_r(const char* name,
               struct group* gr,
               char* buf,
               size_t size,
               struct group** res) {
  return getgr_r(name, 0, gr, buf, size, res);
}

int getgrgid_r(gid_t gid,
               struct group* gr,
               char* buf,
               size_t size,
               struct group** res) {
  return getgr_r(0, gid, gr, buf, size, res);
}