gnu/dist/groff/src/libs/libgroff/tmpfile.cpp

   1 /*      $NetBSD$        */
   2
   3 // -*- C++ -*-
   4 /* Copyright (C) 1989, 1990, 1991, 1992, 2000, 2001, 2003
   5    Free Software Foundation, Inc.
   6      Written by James Clark (jjc@jclark.com)
   7
   8 This file is part of groff.
   9
  10 groff is free software; you can redistribute it and/or modify it under
  11 the terms of the GNU General Public License as published by the Free
  12 Software Foundation; either version 2, or (at your option) any later
  13 version.
  14
  15 groff is distributed in the hope that it will be useful, but WITHOUT ANY
  16 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  17 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  18 for more details.
  19
  20 You should have received a copy of the GNU General Public License along
  21 with groff; see the file COPYING.  If not, write to the Free Software
  22 Foundation, 51 Franklin St - Fifth Floor, Boston, MA 02110-1301, USA. */
  23
  24 #include "lib.h"
  25
  26 #include <errno.h>
  27 #include <stdlib.h>
  28
  29 #include "posix.h"
  30 #include "errarg.h"
  31 #include "error.h"
  32 #include "nonposix.h"
  33
  34 // If this is set, create temporary files there
  35 #define GROFF_TMPDIR_ENVVAR "GROFF_TMPDIR"
  36 // otherwise if this is set, create temporary files there
  37 #define TMPDIR_ENVVAR "TMPDIR"
  38 // otherwise, on MS-DOS or MS-Windows ...
  39 #if defined(__MSDOS__) || defined(_WIN32)
  40 // if either of these is set, create temporary files there
  41 // (giving priority to WIN32_TMPDIR_ENVVAR)
  42 #define WIN32_TMPDIR_ENVVAR "TMP"
  43 #define MSDOS_TMPDIR_ENVVAR "TEMP"
  44 #endif
  45 // otherwise if P_tmpdir is defined, create temporary files there
  46 #ifdef P_tmpdir
  47 # define DEFAULT_TMPDIR P_tmpdir
  48 #else
  49 // otherwise create temporary files here.
  50 # define DEFAULT_TMPDIR "/tmp"
  51 #endif
  52 // Use this as the prefix for temporary filenames.
  53 #define TMPFILE_PREFIX_SHORT ""
  54 #define TMPFILE_PREFIX_LONG "groff"
  55
  56 char *tmpfile_prefix;
  57 size_t tmpfile_prefix_len;
  58 int use_short_postfix = 0;
  59
  60 struct temp_init {
  61   temp_init();
  62   ~temp_init();
  63 } _temp_init;
  64
  65 temp_init::temp_init()
  66 {
  67   // First, choose a location for creating temporary files...
  68   const char *tem;
  69   // using the first match for any of the environment specs in listed order.
  70   if (
  71       (tem = getenv(GROFF_TMPDIR_ENVVAR)) == NULL
  72       && (tem = getenv(TMPDIR_ENVVAR)) == NULL
  73 #if defined(__MSDOS__) || defined(_WIN32)
  74       // If we didn't find a match for either of the above
  75       // (which are preferred, regardless of the host operating system),
  76       // and we are hosted on either MS-Windows or MS-DOS,
  77       // then try the Microsoft conventions.
  78       && (tem = getenv(WIN32_TMPDIR_ENVVAR)) == NULL
  79       && (tem = getenv(MSDOS_TMPDIR_ENVVAR)) == NULL
  80 #endif
  81      )
  82     // If we didn't find an environment spec fall back to this default.
  83     tem = DEFAULT_TMPDIR;
  84   size_t tem_len = strlen(tem);
  85   const char *tem_end = tem + tem_len - 1;
  86   int need_slash = strchr(DIR_SEPS, *tem_end) == NULL ? 1 : 0;
  87   char *tem2 = new char[tem_len + need_slash + 1];
  88   strcpy(tem2, tem);
  89   if (need_slash)
  90     strcat(tem2, "/");
  91   const char *tem3 = TMPFILE_PREFIX_LONG;
  92   if (file_name_max(tem2) <= 14) {
  93     tem3 = TMPFILE_PREFIX_SHORT;
  94     use_short_postfix = 1;
  95   }
  96   tmpfile_prefix_len = tem_len + need_slash + strlen(tem3);
  97   tmpfile_prefix = new char[tmpfile_prefix_len + 1];
  98   strcpy(tmpfile_prefix, tem2);
  99   strcat(tmpfile_prefix, tem3);
 100   a_delete tem2;
 101 }
 102
 103 temp_init::~temp_init()
 104 {
 105   a_delete tmpfile_prefix;
 106 }
 107
 108 /*
 109  *  Generate a temporary name template with a postfix
 110  *  immediately after the TMPFILE_PREFIX.
 111  *  It uses the groff preferences for a temporary directory.
 112  *  Note that no file name is either created or opened,
 113  *  only the *template* is returned.
 114  */
 115
 116 char *xtmptemplate(const char *postfix_long, const char *postfix_short)
 117 {
 118   const char *postfix = use_short_postfix ? postfix_short : postfix_long;
 119   int postlen = 0;
 120   if (postfix)
 121     postlen = strlen(postfix);
 122   char *templ = new char[tmpfile_prefix_len + postlen + 6 + 1];
 123   strcpy(templ, tmpfile_prefix);
 124   if (postlen > 0)
 125     strcat(templ, postfix);
 126   strcat(templ, "XXXXXX");
 127   return templ;
 128 }
 129
 130 // The trick with unlinking the temporary file while it is still in
 131 // use is not portable, it will fail on MS-DOS and most MS-Windows
 132 // filesystems.  So it cannot be used on non-Posix systems.
 133 // Instead, we maintain a list of files to be deleted on exit.
 134 // This should be portable to all platforms.
 135
 136 struct xtmpfile_list {
 137   char *fname;
 138   xtmpfile_list *next;
 139   xtmpfile_list(char *fn) : fname(fn), next(0) {}
 140 };
 141
 142 xtmpfile_list *xtmpfiles_to_delete = 0;
 143
 144 struct xtmpfile_list_init {
 145   ~xtmpfile_list_init();
 146 } _xtmpfile_list_init;
 147
 148 xtmpfile_list_init::~xtmpfile_list_init()
 149 {
 150   xtmpfile_list *x = xtmpfiles_to_delete;
 151   while (x != 0) {
 152     if (unlink(x->fname) < 0)
 153       error("cannot unlink `%1': %2", x->fname, strerror(errno));
 154     xtmpfile_list *tmp = x;
 155     x = x->next;
 156     a_delete tmp->fname;
 157     delete tmp;
 158   }
 159 }
 160
 161 static void add_tmp_file(const char *name)
 162 {
 163   char *s = new char[strlen(name)+1];
 164   strcpy(s, name);
 165   xtmpfile_list *x = new xtmpfile_list(s);
 166   x->next = xtmpfiles_to_delete;
 167   xtmpfiles_to_delete = x;
 168 }
 169
 170 // Open a temporary file and with fatal error on failure.
 171
 172 FILE *xtmpfile(char **namep,
 173                const char *postfix_long, const char *postfix_short,
 174                int do_unlink)
 175 {
 176   char *templ = xtmptemplate(postfix_long, postfix_short);
 177   errno = 0;
 178   int fd = mkstemp(templ);
 179   if (fd < 0)
 180     fatal("cannot create temporary file: %1", strerror(errno));
 181   errno = 0;
 182   FILE *fp = fdopen(fd, FOPEN_RWB); // many callers of xtmpfile use binary I/O
 183   if (!fp)
 184     fatal("fdopen: %1", strerror(errno));
 185   if (do_unlink)
 186     add_tmp_file(templ);
 187   if (namep)
 188     *namep = templ;
 189   else
 190     a_delete templ;
 191   return fp;
 192 }