/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-â
âvi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :viâ
ââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââ¡
â Copyright 2021 Justine Alexandra Roberts Tunney                              â
â                                                                              â
â Permission to use, copy, modify, and/or distribute this software for         â
â any purpose with or without fee is hereby granted, provided that the         â
â above copyright notice and this permission notice appear in all copies.      â
â                                                                              â
â THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                â
â WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                â
â WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             â
â AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         â
â DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        â
â PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               â
â TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             â
â PERFORMANCE OF THIS SOFTWARE.                                                â
ââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââ*/
#include "libc/calls/calls.h"
#include "libc/calls/struct/metastat.internal.h"
#include "libc/calls/struct/stat.h"
#include "libc/calls/syscall-sysv.internal.h"
#include "libc/str/str.h"
#include "libc/sysv/consts/at.h"
#include "libc/sysv/consts/o.h"
#include "libc/sysv/errfuns.h"

#define XNU_F_GETPATH  50
#define XNU_MAXPATHLEN 1024

static inline bool CopyString(char *d, const char *s, size_t n) {
  size_t i;
  for (i = 0; i < n; ++i) {
    if (!(d[i] = s[i])) {
      return true;
    }
  }
  return false;
}

char *sys_getcwd_xnu(char *res, size_t size) {
  int fd;
  union metastat st[2];
  char buf[XNU_MAXPATHLEN], *ret = NULL;
  if ((fd = __sys_openat_nc(AT_FDCWD, ".", O_RDONLY | O_DIRECTORY, 0)) != -1) {
    if (__sys_fstat(fd, &st[0]) != -1) {
      if (st[0].xnu.st_dev && st[0].xnu.st_ino) {
        if (__sys_fcntl(fd, XNU_F_GETPATH, (uintptr_t)buf) != -1) {
          if (__sys_fstatat(AT_FDCWD, buf, &st[1], 0) != -1) {
            if (st[0].xnu.st_dev == st[1].xnu.st_dev &&
                st[0].xnu.st_ino == st[1].xnu.st_ino) {
              if (CopyString(res, buf, size)) {
                ret = res;
              } else {
                erange();
              }
            } else {
              einval();
            }
          }
        }
      } else {
        einval();
      }
    }
    close(fd);
  }
  return ret;
}
