/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2022 Justine Alexandra Roberts Tunney                              │
│                                                                              │
│ Permission to use, copy, modify, and/or distribute this software for         │
│ any purpose with or without fee is hereby granted, provided that the         │
│ above copyright notice and this permission notice appear in all copies.      │
│                                                                              │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
│ PERFORMANCE OF THIS SOFTWARE.                                                │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/calls/strace.internal.h"
#include "libc/calls/syscall_support-nt.internal.h"
#include "libc/dce.h"
#include "libc/macros.internal.h"
#include "libc/nt/accounting.h"
#include "libc/runtime/runtime.h"
#include "libc/str/str.h"
#include "libc/sysv/errfuns.h"

int sys_getlogin(char *, uint32_t);

/**
 * Returns login name.
 */
char *getlogin(void) {
  uint32_t size;
  const char *p, *res;
  char16_t buf16[257];
  static char login[128];
  if (IsBsd()) {
    if (sys_getlogin(login, sizeof(login)) != -1) {
      res = login;
    } else {
      res = 0;
    }
  } else if (IsWindows()) {
    size = ARRAYLEN(buf16);
    if (GetUserName(&buf16, &size)) {
      tprecode16to8(login, sizeof(login), buf16);
      res = login;
    } else {
      __winerr();
      res = 0;
    }
  } else if ((p = getenv("LOGNAME"))) {
    res = p;
  } else {
    enoent();
    res = 0;
  }
  STRACE("getlogin() → %#s% m", res);
  return res;
}