lib/tmpfile.c

   1 // -*- C++ -*-
   2 /* Copyright (C) 1991 Free Software Foundation, Inc.
   3      Written by James Clark (jjc@jclark.uucp)
   4
   5 This file is part of groff.
   6
   7 groff is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 1, or (at your option) any later
  10 version.
  11
  12 groff is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 for more details.
  16
  17 You should have received a copy of the GNU General Public License along
  18 with groff; see the file LICENSE.  If not, write to the Free Software
  19 Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
  20
  21 #include <stdio.h>
  22 #include <errno.h>
  23 #include <string.h>
  24 #include <stdlib.h>
  25 #include <osfcn.h>
  26
  27 #include "lib.h"
  28 #include "errarg.h"
  29 #include "error.h"
  30
  31 extern "C" {
  32   // Sun's stdlib.h fails to declare this.
  33   char *mktemp(char *);
  34 }
  35
  36 // If this is set, create temporary files there
  37 #define GROFF_TMPDIR_ENVVAR "GROFF_TMPDIR"
  38 // otherwise if this is set, create temporary files there
  39 #define TMPDIR_ENVVAR "TMPDIR"
  40 // otherwise create temporary files here.
  41 #define DEFAULT_TMPDIR "/tmp"
  42 // Use this as the prefix for temporary filenames.
  43 #define TMPFILE_PREFIX  "groff"
  44
  45 // Open a temporary file with fatal error on failure.
  46
  47 FILE *xtmpfile()
  48 {
  49   const char *dir = getenv(GROFF_TMPDIR_ENVVAR);
  50   if (!dir) {
  51     dir = getenv(TMPDIR_ENVVAR);
  52     if (!dir)
  53       dir = DEFAULT_TMPDIR;
  54   }
  55
  56   const char *p = strrchr(dir, '/');
  57   int needs_slash = (!p || p[1]);
  58   char *templ = new char[strlen(dir) + needs_slash
  59                             + sizeof(TMPFILE_PREFIX) - 1 + 6 + 1];
  60   strcpy(templ, dir);
  61   if (needs_slash)
  62     strcat(templ, "/");
  63   strcat(templ, TMPFILE_PREFIX);
  64   strcat(templ, "XXXXXX");
  65
  66 #ifdef HAVE_MKSTEMP
  67   errno = 0;
  68   int fd = mkstemp(templ);
  69   if (fd < 0)
  70     fatal("cannot create temporary file: %1", strerror(errno));
  71   errno = 0;
  72   FILE *fp = fdopen(fd, "w+");
  73   if (!fp)
  74     fatal("fdopen: %1", strerror(errno));
  75 #else /* not HAVE_MKSTEMP */
  76   if (!mktemp(templ) || !templ[0])
  77     fatal("cannot create file name for temporary file");
  78   errno = 0;
  79   FILE *fp = fopen(templ, "w+");
  80   if (!fp)
  81     fatal("cannot open `%1': %2", templ, strerror(errno));
  82 #endif /* not HAVE_MKSTEMP */
  83   if (unlink(templ) < 0)
  84     error("cannot unlink `%1': %2", templ, strerror(errno));
  85   a_delete templ;
  86   return fp;
  87 }
  88
  89 #if 0
  90 // If you're not running Unix, the following will do:
  91 FILE *xtmpfile()
  92 {
  93   FILE *fp = tmpfile();
  94   if (!fp)
  95     fatal("couldn't create temporary file");
  96   return fp;
  97 }
  98 #endif