stdio-common/tmpfile.c

   1 /* Open a stdio stream on an anonymous temporary file.  Generic/POSIX version.
   2    Copyright (C) 1991,1993,1996-2000,2002,2003,2007,2009,2011
   3    Free Software Foundation, Inc.
   4    This file is part of the GNU C Library.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, see
  18    <http://www.gnu.org/licenses/>.  */
  19
  20 #include <fcntl.h>
  21 #include <stdio.h>
  22 #include <unistd.h>
  23
  24 #include <iolibio.h>
  25 #define __fdopen INTUSE(_IO_fdopen)
  26 #ifndef tmpfile
  27 # define tmpfile __new_tmpfile
  28 #endif
  29
  30
  31 /* This returns a new stream opened on a temporary file (generated
  32    by tmpnam).  The file is opened with mode "w+b" (binary read/write).
  33    If we couldn't generate a unique filename or the file couldn't
  34    be opened, NULL is returned.  */
  35 FILE *
  36 tmpfile (void)
  37 {
  38   char buf[FILENAME_MAX];
  39   int fd;
  40   FILE *f;
  41
  42   if (__path_search (buf, FILENAME_MAX, NULL, "tmpf", 0))
  43     return NULL;
  44   int flags = 0;
  45 #ifdef FLAGS
  46   flags = FLAGS;
  47 #endif
  48   fd = __gen_tempname (buf, 0, flags, __GT_FILE);
  49   if (fd < 0)
  50     return NULL;
  51
  52   /* Note that this relies on the Unix semantics that
  53      a file is not really removed until it is closed.  */
  54   (void) __unlink (buf);
  55
  56   if ((f = __fdopen (fd, "w+b")) == NULL)
  57     __close (fd);
  58
  59   return f;
  60 }
  61
  62 #ifndef FLAGS /* Not for tmpfile64.  */
  63 # undef tmpfile
  64 # include <shlib-compat.h>
  65 versioned_symbol (libc, __new_tmpfile, tmpfile, GLIBC_2_1);
  66 #endif