src/lib-roff/tmpfile.cpp

   1 /*@ Temporary file management. FIXME consider to use homebrew
   2  *
   3  * Copyright (c) 2014 - 2015 Steffen (Daode) Nurpmeso <sdaoden@users.sf.net>.
   4  *
   5  * Copyright (C) 1989 - 1992, 2000, 2001, 2003
   6  *    Free Software Foundation, Inc.
   7  *      Written by James Clark (jjc@jclark.com)
   8  *
   9  * This is free software; you can redistribute it and/or modify it under
  10  * the terms of the GNU General Public License as published by the Free
  11  * Software Foundation; either version 2, or (at your option) any later
  12  * version.
  13  *
  14  * This is distributed in the hope that it will be useful, but WITHOUT ANY
  15  * WARRANTY; without even the implied warranty of MERCHANTABILITY or
  16  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  17  * for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License along
  20  * with groff; see the file COPYING.  If not, write to the Free Software
  21  * Foundation, 51 Franklin St - Fifth Floor, Boston, MA 02110-1301, USA.
  22  */
  23
  24 #include "config.h"
  25 #include "lib.h"
  26
  27 #include <errno.h>
  28 #include <stdlib.h>
  29
  30 #include "errarg.h"
  31 #include "error.h"
  32 #include "nonposix.h"
  33 #include "posix.h"
  34
  35 // If this is set, create temporary files there
  36 #define GROFF_TMPDIR_ENVVAR U_ROFF_TMPDIR
  37 // otherwise if this is set, create temporary files there
  38 #define TMPDIR_ENVVAR "TMPDIR"
  39 // otherwise, on MS-DOS or MS-Windows ...
  40 #if defined(__MSDOS__) || defined(_WIN32)
  41 // if either of these is set, create temporary files there
  42 // (giving priority to WIN32_TMPDIR_ENVVAR)
  43 # define WIN32_TMPDIR_ENVVAR "TMP"
  44 # define MSDOS_TMPDIR_ENVVAR "TEMP"
  45 #endif
  46 // otherwise if P_tmpdir is defined, create temporary files there
  47 #ifdef P_tmpdir
  48 # define DEFAULT_TMPDIR P_tmpdir
  49 #else
  50 // otherwise create temporary files here.
  51 # define DEFAULT_TMPDIR "/tmp"
  52 #endif
  53 // Use this as the prefix for temporary filenames.
  54 #define TMPFILE_PREFIX_SHORT ""
  55 #define TMPFILE_PREFIX_LONG L_ROFF
  56
  57 char *tmpfile_prefix;
  58 size_t tmpfile_prefix_len;
  59 int use_short_postfix = 0;
  60
  61 struct temp_init { /* FIXME ugh, static ctor intializer */
  62   temp_init();
  63   ~temp_init();
  64 } _temp_init;
  65
  66 temp_init::temp_init()
  67 {
  68   // First, choose a location for creating temporary files...
  69   const char *tem;
  70   // using the first match for any of the environment specs in listed order.
  71   if (
  72       (tem = getenv(GROFF_TMPDIR_ENVVAR)) == NULL
  73       && (tem = getenv(TMPDIR_ENVVAR)) == NULL
  74 #if defined(__MSDOS__) || defined(_WIN32)
  75       // If we didn't find a match for either of the above
  76       // (which are preferred, regardless of the host operating system),
  77       // and we are hosted on either MS-Windows or MS-DOS,
  78       // then try the Microsoft conventions.
  79       && (tem = getenv(WIN32_TMPDIR_ENVVAR)) == NULL
  80       && (tem = getenv(MSDOS_TMPDIR_ENVVAR)) == NULL
  81 #endif
  82      )
  83     // If we didn't find an environment spec fall back to this default.
  84     tem = DEFAULT_TMPDIR;
  85   size_t tem_len = strlen(tem);
  86   const char *tem_end = tem + tem_len - 1;
  87   int need_slash = strchr(DIR_SEPS, *tem_end) == NULL ? 1 : 0;
  88   char *tem2 = new char[tem_len + need_slash + 1];
  89   strcpy(tem2, tem);
  90   if (need_slash)
  91     strcat(tem2, "/");
  92   const char *tem3 = TMPFILE_PREFIX_LONG;
  93   if (file_name_max(tem2) <= 14) {
  94     tem3 = TMPFILE_PREFIX_SHORT;
  95     use_short_postfix = 1;
  96   }
  97   tmpfile_prefix_len = tem_len + need_slash + strlen(tem3);
  98   tmpfile_prefix = new char[tmpfile_prefix_len + 1];
  99   strcpy(tmpfile_prefix, tem2);
 100   strcat(tmpfile_prefix, tem3);
 101   a_delete tem2;
 102 }
 103
 104 temp_init::~temp_init()
 105 {
 106   a_delete tmpfile_prefix;
 107 }
 108
 109 /*
 110  *  Generate a temporary name template with a postfix
 111  *  immediately after the TMPFILE_PREFIX.
 112  *  It uses the groff preferences for a temporary directory.
 113  *  Note that no file name is either created or opened,
 114  *  only the *template* is returned.
 115  */
 116
 117 char *xtmptemplate(const char *postfix_long, const char *postfix_short)
 118 {
 119   const char *postfix = use_short_postfix ? postfix_short : postfix_long;
 120   int postlen = 0;
 121   if (postfix)
 122     postlen = strlen(postfix);
 123   char *templ = new char[tmpfile_prefix_len + postlen + 6 + 1];
 124   strcpy(templ, tmpfile_prefix);
 125   if (postlen > 0)
 126     strcat(templ, postfix);
 127   strcat(templ, "XXXXXX");
 128   return templ;
 129 }
 130
 131 // The trick with unlinking the temporary file while it is still in
 132 // use is not portable, it will fail on MS-DOS and most MS-Windows
 133 // filesystems.  So it cannot be used on non-Posix systems.
 134 // Instead, we maintain a list of files to be deleted on exit.
 135 // This should be portable to all platforms.
 136
 137 class xtmpfile_list
 138 {
 139 public:
 140   char *fname;
 141   xtmpfile_list *next;
 142   xtmpfile_list(char *fn) : fname(fn), next(0) {}
 143 };
 144
 145 xtmpfile_list *xtmpfiles_to_delete = 0;
 146
 147 struct xtmpfile_list_init { /* FIXME ugh, static dtor finalizer */
 148   ~xtmpfile_list_init();
 149 } _xtmpfile_list_init;
 150
 151 xtmpfile_list_init::~xtmpfile_list_init()
 152 {
 153   xtmpfile_list *x = xtmpfiles_to_delete;
 154   while (x != 0) {
 155     if (unlink(x->fname) < 0)
 156       error("cannot unlink `%1': %2", x->fname, strerror(errno));
 157     xtmpfile_list *tmp = x;
 158     x = x->next;
 159     a_delete tmp->fname;
 160     delete tmp;
 161   }
 162 }
 163
 164 static void add_tmp_file(const char *name)
 165 {
 166   char *s = new char[strlen(name)+1];
 167   strcpy(s, name);
 168   xtmpfile_list *x = new xtmpfile_list(s);
 169   x->next = xtmpfiles_to_delete;
 170   xtmpfiles_to_delete = x;
 171 }
 172
 173 // Open a temporary file and with fatal error on failure.
 174
 175 FILE *xtmpfile(char **namep,
 176                const char *postfix_long, const char *postfix_short,
 177                int do_unlink)
 178 {
 179   char *templ = xtmptemplate(postfix_long, postfix_short);
 180   errno = 0;
 181   int fd = mkstemp(templ);
 182   if (fd < 0)
 183     fatal("cannot create temporary file: %1", strerror(errno));
 184   errno = 0;
 185   FILE *fp = fdopen(fd, FOPEN_RWB); // many callers of xtmpfile use binary I/O
 186   if (!fp)
 187     fatal("fdopen: %1", strerror(errno));
 188   if (do_unlink)
 189     add_tmp_file(templ);
 190   if (namep)
 191     *namep = templ;
 192   else
 193     a_delete templ;
 194   return fp;
 195 }
 196
 197 // s-it2-mode