libs/libc/stdlib/lib_mkstemp.c

/****************************************************************************
 * libs/libc/stdlib/lib_mkstemp.c
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.  The
 * ASF licenses this file to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance with the
 * License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
 * License for the specific language governing permissions and limitations
 * under the License.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <nuttx/config.h>
#include <nuttx/compiler.h>

#include <unistd.h>
#include <stdlib.h>
#include <fcntl.h>

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * Name: mkstemp
 *
 * Description:
 *   The mkstemp() function replaces the contents of the string pointed to
 *   by path_template by a unique filename, and returns a file descriptor
 *   for the file open for reading and writing. The function thus prevents
 *   any possible race condition between testing whether the file exists and
 *   opening it for use. The string in path_template should look like a
 *   filename with six trailing 'X' s; mkstemp() replaces each 'X' with a
 *   character from the portable filename character set. The characters are
 *   chosen such that the resulting name does not duplicate the name of an
 *   existing file at the time of a call to mkstemp().
 *
 * Input Parameters:
 *   path_template - The base file name that will be modified to produce
 *     the unique file name.  This must be a full path beginning with /tmp.
 *     This function will modify only the first XXXXXX characters within
 *     that full path.
 *
 * Returned Value:
 *   Upon successful completion, mkstemp() returns an open file descriptor.
 *   Otherwise, -1 is returned if no suitable file could be created.
 *
 ****************************************************************************/

int mkstemp(FAR char *path_template)
{
  FAR char *path = mktemp(path_template);
  int ret = ERROR;

  if (path)
    {
      ret = open(path, O_RDWR | O_CREAT | O_EXCL, 0666);
    }

  return ret;
}