1  /* tempfile.c: handle temporary directory creation (formerly also temporary
       2   * files but this is no longer used).
       3   *
       4   * Copyright (C) 2001, 2003, 2007, 2009, 2011 Colin Watson.
       5   *
       6   * This file is part of man-db.
       7   *
       8   * man-db is free software; you can redistribute it and/or modify it
       9   * under the terms of the GNU General Public License as published by
      10   * the Free Software Foundation; either version 2 of the License, or
      11   * (at your option) any later version.
      12   *
      13   * man-db is distributed in the hope that it will be useful, but
      14   * WITHOUT ANY WARRANTY; without even the implied warranty of
      15   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      16   * GNU General Public License for more details.
      17   *
      18   * You should have received a copy of the GNU General Public License
      19   * along with man-db; if not, write to the Free Software Foundation,
      20   * Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
      21   */
      22  
      23  #ifdef HAVE_CONFIG_H
      24  #  include "config.h"
      25  #endif /* HAVE_CONFIG_H */
      26  
      27  #include <assert.h>
      28  #include <stdbool.h>
      29  #include <stdio.h>
      30  #include <stdlib.h>
      31  #include <unistd.h>
      32  
      33  #include "attribute.h"
      34  #include "xvasprintf.h"
      35  
      36  #include "manconfig.h"
      37  
      38  #include "tempfile.h"
      39  
      40  static bool ATTRIBUTE_PURE running_setid (void)
      41  {
      42  #ifdef HAVE_GETUID
      43  	return getuid () != geteuid () || getgid () != getegid ();
      44  #else /* !HAVE_GETUID */
      45  	return false;
      46  #endif /* HAVE_GETUID */
      47  }
      48  
      49  static const char *path_search (void)
      50  {
      51  	const char *dir = NULL;
      52  
      53  	if (running_setid ()) {
      54  		dir = getenv ("TMPDIR");
      55  		if (!dir || !CAN_ACCESS (dir, W_OK))
      56  			dir = NULL;
      57  		if (!dir) {
      58  			dir = getenv ("TMP");
      59  			if (!dir || !CAN_ACCESS (dir, W_OK))
      60  				dir = NULL;
      61  		}
      62  	}
      63  #ifdef P_tmpdir
      64  	if (!dir) {
      65  		dir = P_tmpdir;
      66  		if (!dir || !CAN_ACCESS (dir, W_OK))
      67  			dir = NULL;
      68  	}
      69  #endif
      70  	if (!dir) {
      71  		dir = "/tmp";
      72  		if (!CAN_ACCESS (dir, W_OK))
      73  			dir = NULL;
      74  	}
      75  
      76  	return dir;
      77  }
      78  
      79  /* Get a sane temporary directory, looking in $TMPDIR, P_tmpdir, and finally
      80   * /tmp.
      81   */
      82  char *create_tempdir (const char *template)
      83  {
      84  	const char *dir = path_search ();
      85  	char *created_dirname;
      86  
      87  	if (!dir)
      88  		return NULL;
      89  	created_dirname = xasprintf ("%s/%sXXXXXX", dir, template);
      90  	assert (created_dirname);
      91  	if (!mkdtemp (created_dirname))
      92  		return NULL;
      93  	return created_dirname;
      94  }