/*	$NetBSD: flags.c,v 1.19 2017/11/09 20:30:02 christos Exp $	*/

/*-
 * Copyright (c) 1990, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Chris Torek.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
#include <sys/types.h>
#include <assert.h>
#include <fcntl.h>
#include <stdio.h>
#include <errno.h>
#include "reentrant.h"
#include "local.h"

/*
 * Return the (stdio) flags for a given mode.  Store the flags
 * to be passed to an open() syscall through *optr.
 * Return 0 on error.
 */
int __sflags(const char *mode, int *optr) {
  int ret, m, o;

  _DIAGASSERT(mode != NULL);

  switch (*mode++) {

    case 'r': /* open for reading */
      ret = __SRD;
      m = O_RDONLY;
      o = 0;
      break;

    case 'w': /* open for writing */
      ret = __SWR;
      m = O_WRONLY;
      o = O_CREAT | O_TRUNC;
      break;

    case 'a': /* open for appending */
      ret = __SWR;
      m = O_WRONLY;
      o = O_CREAT | O_APPEND;
      break;

    default: /* illegal mode */
      errno = EINVAL;
      return 0;
  }

  /*
   * [rwa]\+ or [rwa]b\+ means read and write
   * e means set close on exec.
   * f means open only plain files.
   * l means don't follow symlinks.
   * x means exclusive open.
   */
  for (; *mode; mode++)
    switch (*mode) {
      case '+':
        ret = __SRW;
        m = O_RDWR;
        break;
      case 'b':
        break;
      case 'e':
        o |= O_CLOEXEC;
        break;
      case 'f':
        o |= O_REGULAR;
        break;
      case 'l':
        o |= O_NOFOLLOW;
        break;
      case 'x':
        o |= O_EXCL;
        break;
      default: /* We could produce a warning here */
        break;
    }

  *optr = m | o;
  return ret;
}
