/*

 * SPDX-License-Identifier: ISC

 *

 * Copyright (c) 2001, 2003, 2004, 2008-2011, 2013, 2015, 2017, 2018, 2022

 *  Todd C. Miller <Todd.Miller@sudo.ws>

 *

 * 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.

 */

/*

 * This is an open source non-commercial project. Dear PVS-Studio, please check it.

 * PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com

 */

#include <config.h>

#if (!defined(HAVE_MKDTEMPAT) && !defined(HAVE_MKDTEMPAT_NP)) || \

    (!defined(HAVE_MKOSTEMPSAT) && !defined(HAVE_MKOSTEMPSAT_NP))

#include <sys/stat.h>

#include <errno.h>

#include <fcntl.h>

#include <limits.h>

#include <stdio.h>

#include <stdlib.h>

#if defined(HAVE_STDINT_H)

# include <stdint.h>

#elif defined(HAVE_INTTYPES_H)

# include <inttypes.h>

#endif

#include <string.h>

#include <ctype.h>

#include <unistd.h>

#include "sudo_compat.h"

#include "sudo_rand.h"

#include "pathnames.h"

#define MKTEMP_FILE 1

#define MKTEMP_DIR  2

#define TEMPCHARS "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"

#define NUM_CHARS (sizeof(TEMPCHARS) - 1)

#define MIN_X   6

#define MKOTEMP_FLAGS (O_APPEND | O_CLOEXEC | O_SYNC)

static int

mktemp_internal(int dfd, char *path, int slen, int mode, int flags)

{

  char *start, *cp, *ep;

  const char tempchars[] = TEMPCHARS;

  unsigned int tries;

  size_t len;

  int fd;

  len = strlen(path);

  if (len < MIN_X || slen < 0 || (size_t)slen > len - MIN_X) {

    errno = EINVAL;

    return -1;

  }

  ep = path + len - slen;

  for (start = ep; start > path && start[-1] == 'X'; start--)

    ;

  if (ep - start < MIN_X) {

    errno = EINVAL;

    return -1;

  }

  if (flags & ~MKOTEMP_FLAGS) {

    errno = EINVAL;

    return -1;

  }

  flags |= O_CREAT | O_EXCL | O_RDWR;

  tries = INT_MAX;

  do {

    cp = start;

    do {

      unsigned short rbuf[16];

      unsigned int i;

      /*

       * Avoid lots of arc4random() calls by using

       * a buffer sized for up to 16 Xs at a time.

       */

      arc4random_buf(rbuf, sizeof(rbuf));

      for (i = 0; i < nitems(rbuf) && cp != ep; i++)

        *cp++ = tempchars[rbuf[i] % NUM_CHARS];

    } while (cp != ep);

    switch (mode) {

    case MKTEMP_FILE:

      fd = openat(dfd, path, flags, S_IRUSR|S_IWUSR);

      if (fd != -1 || errno != EEXIST)

        return fd;

      break;

    case MKTEMP_DIR:

      if (mkdirat(dfd, path, S_IRWXU) == 0)

        return 0;

      if (errno != EEXIST)

        return -1;

      break;

    }

  } while (--tries);

  errno = EEXIST;

  return -1;

}

char *

sudo_mkdtemp(char *path)

{

  if (mktemp_internal(AT_FDCWD, path, 0, MKTEMP_DIR, 0) == -1)

    return NULL;

  return path;

}

char *

sudo_mkdtempat(int dfd, char *path)

{

  if (mktemp_internal(dfd, path, 0, MKTEMP_DIR, 0) == -1)

    return NULL;

  return path;

}

int

sudo_mkostempsat(int dfd, char *path, int slen, int flags)

{

  return mktemp_internal(dfd, path, slen, MKTEMP_FILE, flags);

}

#ifdef notyet

int

sudo_mkostemps(char *path, int slen, int flags)

{

  return mktemp_internal(AT_FDCWD, path, slen, MKTEMP_FILE, flags);

}

#endif

int

sudo_mkstemp(char *path)

{

  return mktemp_internal(AT_FDCWD, path, 0, MKTEMP_FILE, 0);

}

#ifdef notyet

int

sudo_mkostemp(char *path, int flags)

{

  return mktemp_internal(AT_FDCWD, path, 0, MKTEMP_FILE, flags);

}

#endif

int

sudo_mkstemps(char *path, int slen)

{

  return mktemp_internal(AT_FDCWD, path, slen, MKTEMP_FILE, 0);

}

#endif /* !HAVE_MKDTEMPAT || !HAVE_MKOSTEMPSAT */