/* Id: compat_mkdtemp.c,v 1.4 2021/09/19 15:02:55 schwarze Exp  */
/*
* Copyright (c) 2015, 2021 Ingo Schwarze <[email protected]>
*
* Permission to use, copy, modify, and 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.
*
* The algorithm of this function is inspired by OpenBSD mkdtemp(3)
* by Theo de Raadt and Todd Miller, but the code differs.
*/
#include "config.h"

#include <sys/stat.h>
#include <errno.h>
#include <limits.h>
#include <stdlib.h>
#include <string.h>

char *
mkdtemp(char *path)
{
       char            *start, *cp;
       unsigned         int tries;

       start = strchr(path, '\0');
       while (start > path && start[-1] == 'X')
               start--;

       for (tries = INT_MAX; tries; tries--) {
               if (mktemp(path) == NULL)
                       return NULL;
               if (mkdir(path, S_IRUSR | S_IWUSR | S_IXUSR) == 0)
                       return path;
               for (cp = start; *cp != '\0'; cp++)
                       *cp = 'X';
               if (errno != EEXIST)
                       return NULL;
       }
       errno = EEXIST;
       return NULL;
}