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/* Utility to pick a temporary filename prefix.

   Copyright (C) 1996, 1997, 1998, 2001 Free Software Foundation, Inc.

This file is part of the libiberty library.

Libiberty is free software; you can redistribute it and/or

modify it under the terms of the GNU Library General Public

License as published by the Free Software Foundation; either

version 2 of the License, or (at your option) any later version.

Libiberty 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

Library General Public License for more details.

You should have received a copy of the GNU Library General Public

License along with libiberty; see the file COPYING.LIB.  If not,

write to the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor,

Boston, MA 02110-1301, USA.  */

#ifdef HAVE_CONFIG_H

#include "config.h"

#endif

#include <stdio.h>      /* May get P_tmpdir.  */

#include <sys/types.h>

#ifdef HAVE_UNISTD_H

#include <unistd.h>

#endif

#ifdef HAVE_STDLIB_H

#include <stdlib.h>

#endif

#ifdef HAVE_STRING_H

#include <string.h>

#endif

#ifdef HAVE_SYS_FILE_H

#include <sys/file.h>   /* May get R_OK, etc. on some systems.  */

#endif

#ifndef R_OK

#define R_OK 4

#define W_OK 2

#define X_OK 1

#endif

#include "libiberty.h"

extern int mkstemps (char *, int);

/* '/' works just fine on MS-DOS based systems.  */

#ifndef DIR_SEPARATOR

#define DIR_SEPARATOR '/'

#endif

/* Name of temporary file.

   mktemp requires 6 trailing X's.  */

#define TEMP_FILE "ccXXXXXX"

#define TEMP_FILE_LEN (sizeof(TEMP_FILE) - 1)

/* Subroutine of choose_tmpdir.

   If BASE is non-NULL, return it.

   Otherwise it checks if DIR is a usable directory.

   If success, DIR is returned.

   Otherwise NULL is returned.  */

static inline const char *try_dir (const char *, const char *);

static inline const char *

try_dir (const char *dir, const char *base)

{

  if (base != 0)

    return base;

  if (dir != 0

      && access (dir, R_OK | W_OK | X_OK) == 0)

    return dir;

  return 0;

}

static const char tmp[] = { DIR_SEPARATOR, 't', 'm', 'p', 0 };

static const char usrtmp[] =

{ DIR_SEPARATOR, 'u', 's', 'r', DIR_SEPARATOR, 't', 'm', 'p', 0 };

static const char vartmp[] =

{ DIR_SEPARATOR, 'v', 'a', 'r', DIR_SEPARATOR, 't', 'm', 'p', 0 };

static char *memoized_tmpdir;

/*

@deftypefn Replacement char* choose_tmpdir ()

Returns a pointer to a directory path suitable for creating temporary

files in.

@end deftypefn

*/

char *

choose_tmpdir (void)

{

  const char *base = 0;

  char *tmpdir;

  unsigned int len;

  if (memoized_tmpdir)

    return memoized_tmpdir;

  base = try_dir (getenv ("TMPDIR"), base);

  base = try_dir (getenv ("TMP"), base);

  base = try_dir (getenv ("TEMP"), base);

#ifdef P_tmpdir

  base = try_dir (P_tmpdir, base);

#endif

  /* Try /var/tmp, /usr/tmp, then /tmp.  */

  base = try_dir (vartmp, base);

  base = try_dir (usrtmp, base);

  base = try_dir (tmp, base);

  /* If all else fails, use the current directory!  */

  if (base == 0)

    base = ".";

  /* Append DIR_SEPARATOR to the directory we've chosen

     and return it.  */

  len = strlen (base);

  tmpdir = XNEWVEC (char, len + 2);

  strcpy (tmpdir, base);

  tmpdir[len] = DIR_SEPARATOR;

  tmpdir[len+1] = '\0';

  memoized_tmpdir = tmpdir;

  return tmpdir;

}

/*

@deftypefn Replacement char* make_temp_file (const char *@var{suffix})

Return a temporary file name (as a string) or @code{NULL} if unable to

create one.  @var{suffix} is a suffix to append to the file name.  The

string is @code{malloc}ed, and the temporary file has been created.

@end deftypefn

*/

char *

make_temp_file (const char *suffix)

{

  const char *base = choose_tmpdir ();

  char *temp_filename;

  int base_len, suffix_len;

  int fd;

  if (suffix == 0)

    suffix = "";

  base_len = strlen (base);

  suffix_len = strlen (suffix);

  temp_filename = XNEWVEC (char, base_len

                           + TEMP_FILE_LEN

                           + suffix_len + 1);

  strcpy (temp_filename, base);

  strcpy (temp_filename + base_len, TEMP_FILE);

  strcpy (temp_filename + base_len + TEMP_FILE_LEN, suffix);

  fd = mkstemps (temp_filename, suffix_len);

  /* If mkstemps failed, then something bad is happening.  Maybe we should

     issue a message about a possible security attack in progress?  */

  if (fd == -1)

    abort ();

  /* Similarly if we can not close the file.  */

  if (close (fd))

    abort ();

  return temp_filename;

}