sysdeps/mach/hurd/tmpfile.c

   1 /* Open a stdio stream on an anonymous temporary file.  Hurd version.
   2    Copyright (C) 2001-2018 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    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <stdio.h>
  20 #include <hurd.h>
  21 #include <hurd/fs.h>
  22 #include <hurd/fd.h>
  23 #include <fcntl.h>
  24 #include <unistd.h>
  25 #include <iolibio.h>
  26
  27 /* This returns a new stream opened on a temporary file (generated
  28    by tmpnam).  The file is opened with mode "w+b" (binary read/write).
  29    If we couldn't generate a unique filename or the file couldn't
  30    be opened, NULL is returned.  */
  31 FILE *
  32 __tmpfile (void)
  33 {
  34   error_t err;
  35   file_t file;
  36   int fd;
  37   FILE *f;
  38
  39   /* Get a port to the directory that will contain the file.  */
  40   const char *dirname = __libc_secure_getenv ("TMPDIR") ?: P_tmpdir;
  41   file_t dir = __file_name_lookup (dirname, 0, 0);
  42   if (dir == MACH_PORT_NULL)
  43     return NULL;
  44
  45   /* Create an unnamed file in the temporary directory.  */
  46   err = __dir_mkfile (dir, O_RDWR, S_IRUSR | S_IWUSR, &file);
  47   __mach_port_deallocate (__mach_task_self (), dir);
  48   if (err)
  49     return __hurd_fail (err), NULL;
  50
  51   /* Get a file descriptor for that port.  POSIX.1 requires that streams
  52      returned by tmpfile allocate file descriptors as fopen would.  */
  53   fd = _hurd_intern_fd (file, O_RDWR, 1); /* dealloc on error */
  54   if (fd < 0)
  55     return NULL;
  56
  57   /* Open a stream on the unnamed file.
  58      It will cease to exist when this stream is closed.  */
  59   if ((f = _IO_fdopen (fd, "w+b")) == NULL)
  60     __close (fd);
  61
  62   return f;
  63 }
  64
  65 #include <shlib-compat.h>
  66 versioned_symbol (libc, __tmpfile, tmpfile, GLIBC_2_1);
  67
  68 weak_alias (__tmpfile, tmpfile64)