/* Copyright (C) 1999, 2001-2002, 2006, 2009-2025 Free Software Foundation,

   Inc.

   This file is part of the GNU C Library.

   This file is free software: you can redistribute it and/or modify

   it under the terms of the GNU Lesser General Public License as

   published by the Free Software Foundation, either version 3 of the

   License, or (at your option) any later version.

   This file is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

   GNU Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public License

   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */

/* Extracted from sysdeps/posix/tempname.c.  */

#include <config.h>

/* Specification.  */

#include "tmpdir.h"

#include <stdlib.h>

#include <string.h>

#include <errno.h>

#ifndef __set_errno

# define __set_errno(Val) errno = (Val)

#endif

#include <stdio.h>

#ifndef P_tmpdir

# ifdef _P_tmpdir /* native Windows */

#  define P_tmpdir _P_tmpdir

# else

#  define P_tmpdir "/tmp"

# endif

#endif

#include <sys/stat.h>

#if defined _WIN32 && ! defined __CYGWIN__

# define WIN32_LEAN_AND_MEAN  /* avoid including junk */

# include <windows.h>

#endif

#include "pathmax.h"

#if defined _WIN32 && ! defined __CYGWIN__

/* Don't assume that UNICODE is not defined.  */

# undef GetTempPath

# define GetTempPath GetTempPathA

#endif

#if _LIBC

# define struct_stat64 struct stat64

#else

# define struct_stat64 struct stat

# define __libc_secure_getenv secure_getenv

# define __xstat64(version, path, buf) stat (path, buf)

#endif

/* Pathname support.

   ISSLASH(C)           tests whether C is a directory separator character.

 */

#if defined _WIN32 || defined __CYGWIN__ || defined __EMX__ || defined __DJGPP__

  /* Native Windows, Cygwin, OS/2, DOS */

# define ISSLASH(C) ((C) == '/' || (C) == '\\')

#else

  /* Unix */

# define ISSLASH(C) ((C) == '/')

#endif

/* Return nonzero if DIR is an existent directory.  */

static bool

direxists (const char *dir)

{

  struct_stat64 buf;

  return __xstat64 (_STAT_VER, dir, &buf) == 0 && S_ISDIR (buf.st_mode);

}

/* Path search algorithm, for tmpnam, tmpfile, etc.  If DIR is

   non-null and exists, uses it; otherwise uses the first of $TMPDIR,

   P_tmpdir, /tmp that exists.  Copies into TMPL a template suitable

   for use with mk[s]temp.  Will fail (-1) if DIR is non-null and

   doesn't exist, none of the searched dirs exists, or there's not

   enough space in TMPL. */

int

path_search (char *tmpl, size_t tmpl_len, const char *dir, const char *pfx,

             bool try_tmpdir)

{

  const char *d;

  size_t dlen, plen;

  bool add_slash;

  if (!pfx || !pfx[0])

    {

      pfx = "file";

      plen = 4;

    }

  else

    {

      plen = strlen (pfx);

      if (plen > 5)

        plen = 5;

    }

  if (try_tmpdir)

    {

      d = __libc_secure_getenv ("TMPDIR");

      if (d != NULL && direxists (d))

        dir = d;

      else if (dir != NULL && direxists (dir))

        /* nothing */ ;

      else

        dir = NULL;

    }

  if (dir == NULL)

    {

#if defined _WIN32 && ! defined __CYGWIN__

      char dirbuf[PATH_MAX];

      DWORD retval;

      /* Find Windows temporary file directory.

         We try this before P_tmpdir because Windows defines P_tmpdir to "\\"

         and will therefore try to put all temporary files in the root

         directory (unless $TMPDIR is set).  */

      retval = GetTempPath (PATH_MAX, dirbuf);

      if (retval > 0 && retval < PATH_MAX && direxists (dirbuf))

        dir = dirbuf;

      else

#endif

      if (direxists (P_tmpdir))

        dir = P_tmpdir;

      else if (strcmp (P_tmpdir, "/tmp") != 0 && direxists ("/tmp"))

        dir = "/tmp";

      else

        {

          __set_errno (ENOENT);

          return -1;

        }

    }

  dlen = strlen (dir);

#ifdef __VMS

  add_slash = 0;

#else

  add_slash = dlen != 0 && !ISSLASH (dir[dlen - 1]);

#endif

  /* check we have room for "${dir}/${pfx}XXXXXX\0" */

  if (tmpl_len < dlen + add_slash + plen + 6 + 1)

    {

      __set_errno (EINVAL);

      return -1;

    }

  memcpy (tmpl, dir, dlen);

  sprintf (tmpl + dlen, &"/%.*sXXXXXX"[!add_slash], (int) plen, pfx);

  return 0;

}