1  /* Open a stdio stream on an anonymous temporary file.  Generic/POSIX version.
       2     Copyright (C) 1991-2023 Free Software Foundation, Inc.
       3     This file is part of the GNU C Library.
       4  
       5     The GNU C Library is free software; you can redistribute it and/or
       6     modify it under the terms of the GNU Lesser General Public
       7     License as published by the Free Software Foundation; either
       8     version 2.1 of the License, or (at your option) any later version.
       9  
      10     The GNU C Library is distributed in the hope that it will be useful,
      11     but WITHOUT ANY WARRANTY; without even the implied warranty of
      12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      13     Lesser General Public License for more details.
      14  
      15     You should have received a copy of the GNU Lesser General Public
      16     License along with the GNU C Library; if not, see
      17     <https://www.gnu.org/licenses/>.  */
      18  
      19  #include <fcntl.h>
      20  #include <stdio.h>
      21  #include <unistd.h>
      22  
      23  #include <iolibio.h>
      24  #define __fdopen _IO_fdopen
      25  #ifndef tmpfile
      26  # define tmpfile __new_tmpfile
      27  #endif
      28  
      29  
      30  /* This returns a new stream opened on a temporary file (generated
      31     by tmpnam).  The file is opened with mode "w+b" (binary read/write).
      32     If we couldn't generate a unique filename or the file couldn't
      33     be opened, NULL is returned.  */
      34  FILE *
      35  tmpfile (void)
      36  {
      37    int fd;
      38    FILE *f;
      39    int flags = 0;
      40  #ifdef FLAGS
      41    flags = FLAGS;
      42  #endif
      43  
      44    /* First try a system specific method.  */
      45    fd = __gen_tempfd (flags);
      46  
      47    if (fd < 0)
      48      {
      49        char buf[FILENAME_MAX];
      50  
      51        if (__path_search (buf, sizeof buf, NULL, "tmpf", 0))
      52  	return NULL;
      53  
      54        fd = __gen_tempname (buf, 0, flags, __GT_FILE);
      55        if (fd < 0)
      56  	return NULL;
      57  
      58        /* Note that this relies on the Unix semantics that
      59  	 a file is not really removed until it is closed.  */
      60        (void) __unlink (buf);
      61      }
      62  
      63    if ((f = __fdopen (fd, "w+b")) == NULL)
      64      __close (fd);
      65  
      66    return f;
      67  }
      68  
      69  #if !defined O_LARGEFILE || O_LARGEFILE == 0
      70  weak_alias (__new_tmpfile, tmpfile64)
      71  #endif
      72  
      73  #ifndef FLAGS /* Not for tmpfile64.  */
      74  # undef tmpfile
      75  # include <shlib-compat.h>
      76  versioned_symbol (libc, __new_tmpfile, tmpfile, GLIBC_2_1);
      77  #endif