lib/sh/tmpfile.c

   1 /*
   2  * tmpfile.c - functions to create and safely open temp files for the shell.
   3  */
   4
   5 /* Copyright (C) 2000 Free Software Foundation, Inc.
   6
   7    This file is part of GNU Bash, the Bourne Again SHell.
   8
   9    Bash is free software; you can redistribute it and/or modify it
  10    under the terms of the GNU General Public License as published by
  11    the Free Software Foundation; either version 2, or (at your option)
  12    any later version.
  13
  14    Bash is distributed in the hope that it will be useful, but WITHOUT
  15    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  16    or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
  17    License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with Bash; see the file COPYING.  If not, write to the Free
  21    Software Foundation, 59 Temple Place, Suite 330, Boston, MA 02111 USA. */
  22
  23 #include <config.h>
  24
  25 #include <bashtypes.h>
  26 #include <posixstat.h>
  27 #include <filecntl.h>
  28
  29 #if defined (HAVE_UNISTD_H)
  30 #  include <unistd.h>
  31 #endif
  32
  33 #include <stdio.h>
  34 #include <errno.h>
  35
  36 #include <shell.h>
  37
  38 #ifndef errno
  39 extern int errno;
  40 #endif
  41
  42 #define BASEOPENFLAGS   (O_CREAT | O_TRUNC | O_EXCL)
  43
  44 #define DEFAULT_TMPDIR          "."     /* bogus default, should be changed */
  45 #define DEFAULT_NAMEROOT        "shtmp"
  46
  47 extern int dollar_dollar_pid;
  48
  49 static char *sys_tmpdir = (char *)NULL;
  50 static int ntmpfiles;
  51 static int tmpnamelen = -1;
  52 static unsigned long filenum = 1L;
  53
  54 static char *
  55 get_sys_tmpdir ()
  56 {
  57   struct stat sb;
  58
  59   if (sys_tmpdir)
  60     return sys_tmpdir;
  61
  62   sys_tmpdir = "/tmp";
  63   if (stat (sys_tmpdir, &sb) == 0)
  64     return sys_tmpdir;
  65
  66   sys_tmpdir = "/var/tmp";
  67   if (stat (sys_tmpdir, &sb) == 0)
  68     return sys_tmpdir;
  69
  70   sys_tmpdir = "/usr/tmp";
  71   if (stat (sys_tmpdir, &sb) == 0)
  72     return sys_tmpdir;
  73
  74 #ifdef P_tmpdir
  75   sys_tmpdir = P_tmpdir;
  76 #else
  77   sys_tmpdir = DEFAULT_TMPDIR;
  78 #endif
  79
  80   return sys_tmpdir;
  81 }
  82
  83 static char *
  84 get_tmpdir (flags)
  85      int flags;
  86 {
  87   char *tdir;
  88
  89   tdir = (flags & MT_USETMPDIR) ? get_string_value ("TMPDIR") : (char *)NULL;
  90   if (tdir == 0)
  91     tdir = get_sys_tmpdir ();
  92
  93 #if defined (HAVE_PATHCONF) && defined (_PC_NAME_MAX)
  94   if (tmpnamelen == -1)
  95     tmpnamelen = pathconf (tdir, _PC_NAME_MAX);
  96 #else
  97   tmpnamelen = 0;
  98 #endif
  99
 100   return tdir;
 101 }
 102
 103 char *
 104 sh_mktmpname (nameroot, flags)
 105      char *nameroot;
 106      int flags;
 107 {
 108   char *filename, *tdir;
 109   struct stat sb;
 110   int r, tdlen;
 111
 112   filename = xmalloc (PATH_MAX + 1);
 113   tdir = get_tmpdir (flags);
 114   tdlen = strlen (tdir);
 115
 116   if (nameroot == 0)
 117     nameroot = DEFAULT_NAMEROOT;
 118
 119   while (1)
 120     {
 121       filenum *= (int)time ((time_t *)0) * dollar_dollar_pid *
 122                 ((flags & MT_USERANDOM) ? get_random_number () : ntmpfiles++);
 123       sprintf (filename, "%s/%s-%lu", tdir, nameroot, filenum);
 124       if (tmpnamelen > 0 && tmpnamelen < 32)
 125         filename[tdlen + 1 + tmpnamelen] = '\0';
 126 #ifdef HAVE_LSTAT
 127       r = lstat (filename, &sb);
 128 #else
 129       r = stat (filename, &sb);
 130 #endif
 131       if (r < 0 && errno == ENOENT)
 132         break;
 133     }
 134
 135   return filename;
 136 }
 137
 138 int
 139 sh_mktmpfd (nameroot, flags, namep)
 140      char *nameroot;
 141      int flags;
 142      char **namep;
 143 {
 144   char *filename, *tdir;
 145   int fd, tdlen;
 146
 147   filename = xmalloc (PATH_MAX + 1);
 148   tdir = get_tmpdir (flags);
 149   tdlen = strlen (tdir);
 150
 151   if (nameroot == 0)
 152     nameroot = DEFAULT_NAMEROOT;
 153
 154   do
 155     {
 156       filenum *= (int)time ((time_t *)0) * dollar_dollar_pid *
 157                 ((flags & MT_USERANDOM) ? get_random_number () : ntmpfiles++);
 158       sprintf (filename, "%s/%s-%lu", tdir, nameroot, filenum);
 159       if (tmpnamelen > 0 && tmpnamelen < 32)
 160         filename[tdlen + 1 + tmpnamelen] = '\0';
 161       fd = open (filename, BASEOPENFLAGS | ((flags & MT_READWRITE) ? O_RDWR : O_WRONLY), 0600);
 162     }
 163   while (fd < 0 && errno == EEXIST);
 164
 165   if (namep)
 166     *namep = filename;
 167   else
 168     free (filename);
 169
 170   return fd;
 171 }
 172
 173 FILE *
 174 sh_mktmpfp (nameroot, flags, namep)
 175      char *nameroot;
 176      int flags;
 177      char **namep;
 178 {
 179   int fd;
 180
 181   fd = sh_mktmpfd (nameroot, flags, namep);
 182   return ((fd >= 0) ? (fdopen (fd, (flags & MT_READWRITE) ? "w+" : "w")) : (FILE *)NULL);
 183 }