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
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation, either version 3 of the License, or
  12    (at your option) any later version.
  13
  14    Bash is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with Bash.  If not, see <http://www.gnu.org/licenses/>.
  21 */
  22
  23 #include <config.h>
  24
  25 #include <bashtypes.h>
  26 #include <posixstat.h>
  27 #include <posixtime.h>
  28 #include <filecntl.h>
  29
  30 #if defined (HAVE_UNISTD_H)
  31 #  include <unistd.h>
  32 #endif
  33
  34 #include <stdio.h>
  35 #include <errno.h>
  36
  37 #include <shell.h>
  38
  39 #ifndef errno
  40 extern int errno;
  41 #endif
  42
  43 #define BASEOPENFLAGS   (O_CREAT | O_TRUNC | O_EXCL)
  44
  45 #define DEFAULT_TMPDIR          "."     /* bogus default, should be changed */
  46 #define DEFAULT_NAMEROOT        "shtmp"
  47
  48 extern pid_t dollar_dollar_pid;
  49
  50 static char *get_sys_tmpdir __P((void));
  51 static char *get_tmpdir __P((int));
  52
  53 static char *sys_tmpdir = (char *)NULL;
  54 static int ntmpfiles;
  55 static int tmpnamelen = -1;
  56 static unsigned long filenum = 1L;
  57
  58 static char *
  59 get_sys_tmpdir ()
  60 {
  61   if (sys_tmpdir)
  62     return sys_tmpdir;
  63
  64 #ifdef P_tmpdir
  65   sys_tmpdir = P_tmpdir;
  66   if (file_iswdir (sys_tmpdir))
  67     return sys_tmpdir;
  68 #endif
  69
  70   sys_tmpdir = "/tmp";
  71   if (file_iswdir (sys_tmpdir))
  72     return sys_tmpdir;
  73
  74   sys_tmpdir = "/var/tmp";
  75   if (file_iswdir (sys_tmpdir))
  76     return sys_tmpdir;
  77
  78   sys_tmpdir = "/usr/tmp";
  79   if (file_iswdir (sys_tmpdir))
  80     return sys_tmpdir;
  81
  82   sys_tmpdir = DEFAULT_TMPDIR;
  83
  84   return sys_tmpdir;
  85 }
  86
  87 static char *
  88 get_tmpdir (flags)
  89      int flags;
  90 {
  91   char *tdir;
  92
  93   tdir = (flags & MT_USETMPDIR) ? get_string_value ("TMPDIR") : (char *)NULL;
  94   if (tdir && (file_iswdir (tdir) == 0 || strlen (tdir) > PATH_MAX))
  95     tdir = 0;
  96
  97   if (tdir == 0)
  98     tdir = get_sys_tmpdir ();
  99
 100 #if defined (HAVE_PATHCONF) && defined (_PC_NAME_MAX)
 101   if (tmpnamelen == -1)
 102     tmpnamelen = pathconf (tdir, _PC_NAME_MAX);
 103 #else
 104   tmpnamelen = 0;
 105 #endif
 106
 107   return tdir;
 108 }
 109
 110 char *
 111 sh_mktmpname (nameroot, flags)
 112      char *nameroot;
 113      int flags;
 114 {
 115   char *filename, *tdir, *lroot;
 116   struct stat sb;
 117   int r, tdlen;
 118
 119   filename = (char *)xmalloc (PATH_MAX + 1);
 120   tdir = get_tmpdir (flags);
 121   tdlen = strlen (tdir);
 122
 123   lroot = nameroot ? nameroot : DEFAULT_NAMEROOT;
 124
 125 #ifdef USE_MKTEMP
 126   sprintf (filename, "%s/%s.XXXXXX", tdir, lroot);
 127   if (mktemp (filename) == 0)
 128     {
 129       free (filename);
 130       filename = NULL;
 131     }
 132 #else  /* !USE_MKTEMP */
 133   while (1)
 134     {
 135       filenum = (filenum << 1) ^
 136                 (unsigned long) time ((time_t *)0) ^
 137                 (unsigned long) dollar_dollar_pid ^
 138                 (unsigned long) ((flags & MT_USERANDOM) ? get_random_number () : ntmpfiles++);
 139       sprintf (filename, "%s/%s-%lu", tdir, lroot, filenum);
 140       if (tmpnamelen > 0 && tmpnamelen < 32)
 141         filename[tdlen + 1 + tmpnamelen] = '\0';
 142 #  ifdef HAVE_LSTAT
 143       r = lstat (filename, &sb);
 144 #  else
 145       r = stat (filename, &sb);
 146 #  endif
 147       if (r < 0 && errno == ENOENT)
 148         break;
 149     }
 150 #endif /* !USE_MKTEMP */
 151
 152   return filename;
 153 }
 154
 155 int
 156 sh_mktmpfd (nameroot, flags, namep)
 157      char *nameroot;
 158      int flags;
 159      char **namep;
 160 {
 161   char *filename, *tdir, *lroot;
 162   int fd, tdlen;
 163
 164   filename = (char *)xmalloc (PATH_MAX + 1);
 165   tdir = get_tmpdir (flags);
 166   tdlen = strlen (tdir);
 167
 168   lroot = nameroot ? nameroot : DEFAULT_NAMEROOT;
 169
 170 #ifdef USE_MKSTEMP
 171   sprintf (filename, "%s/%s.XXXXXX", tdir, lroot);
 172   fd = mkstemp (filename);
 173   if (fd < 0 || namep == 0)
 174     {
 175       free (filename);
 176       filename = NULL;
 177     }
 178   if (namep)
 179     *namep = filename;
 180   return fd;
 181 #else /* !USE_MKSTEMP */
 182   do
 183     {
 184       filenum = (filenum << 1) ^
 185                 (unsigned long) time ((time_t *)0) ^
 186                 (unsigned long) dollar_dollar_pid ^
 187                 (unsigned long) ((flags & MT_USERANDOM) ? get_random_number () : ntmpfiles++);
 188       sprintf (filename, "%s/%s-%lu", tdir, lroot, filenum);
 189       if (tmpnamelen > 0 && tmpnamelen < 32)
 190         filename[tdlen + 1 + tmpnamelen] = '\0';
 191       fd = open (filename, BASEOPENFLAGS | ((flags & MT_READWRITE) ? O_RDWR : O_WRONLY), 0600);
 192     }
 193   while (fd < 0 && errno == EEXIST);
 194
 195   if (namep)
 196     *namep = filename;
 197   else
 198     free (filename);
 199
 200   return fd;
 201 #endif /* !USE_MKSTEMP */
 202 }
 203
 204 FILE *
 205 sh_mktmpfp (nameroot, flags, namep)
 206      char *nameroot;
 207      int flags;
 208      char **namep;
 209 {
 210   int fd;
 211   FILE *fp;
 212
 213   fd = sh_mktmpfd (nameroot, flags, namep);
 214   if (fd < 0)
 215     return ((FILE *)NULL);
 216   fp = fdopen (fd, (flags & MT_READWRITE) ? "w+" : "w");
 217   if (fp == 0)
 218     close (fd);
 219   return fp;
 220 }