1/* Copyright (C) 1993-2017 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
8
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <http://www.gnu.org/licenses/>.
17
18 As a special exception, if you link the code in this file with
19 files compiled with a GNU compiler to produce an executable,
20 that does not cause the resulting executable to be covered by
21 the GNU Lesser General Public License. This exception does not
22 however invalidate any other reasons why the executable file
23 might be covered by the GNU Lesser General Public License.
24 This exception applies to code released by its copyright holders
25 in files containing the exception. */
26
27#include "libioP.h"
28#include "stdio.h"
29#include <fcntl.h>
30#include <stdlib.h>
31#include <unistd.h>
32
33#include <shlib-compat.h>
34#include <fd_to_filename.h>
35
36#include <kernel-features.h>
37
38FILE *
39freopen (const char *filename, const char *mode, FILE *fp)
40{
41 FILE *result;
42 CHECK_FILE (fp, NULL);
43 if (!(fp->_flags & _IO_IS_FILEBUF))
44 return NULL;
45 _IO_acquire_lock (fp);
46 int fd = _IO_fileno (fp);
47 const char *gfilename = (filename == NULL && fd >= 0
48 ? fd_to_filename (fd) : filename);
49 fp->_flags2 |= _IO_FLAGS2_NOCLOSE;
50#if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_1)
51 if (&_IO_stdin_used == NULL)
52 {
53 /* If the shared C library is used by the application binary which
54 was linked against the older version of libio, we just use the
55 older one even for internal use to avoid trouble since a pointer
56 to the old libio may be passed into shared C library and wind
57 up here. */
58 _IO_old_file_close_it (fp);
59 _IO_JUMPS_FILE_plus (fp) = &_IO_old_file_jumps;
60 result = _IO_old_file_fopen (fp, gfilename, mode);
61 }
62 else
63#endif
64 {
65 _IO_file_close_it (fp);
66 _IO_JUMPS_FILE_plus (fp) = &_IO_file_jumps;
67 if (_IO_vtable_offset (fp) == 0 && fp->_wide_data != NULL)
68 fp->_wide_data->_wide_vtable = &_IO_wfile_jumps;
69 result = _IO_file_fopen (fp, gfilename, mode, 1);
70 if (result != NULL)
71 result = __fopen_maybe_mmap (result);
72 }
73 fp->_flags2 &= ~_IO_FLAGS2_NOCLOSE;
74 if (result != NULL)
75 {
76 /* unbound stream orientation */
77 result->_mode = 0;
78
79 if (fd != -1)
80 {
81#ifdef O_CLOEXEC
82# ifndef __ASSUME_DUP3
83 int newfd;
84 if (__have_dup3 < 0)
85 newfd = -1;
86 else
87 newfd =
88# endif
89 __dup3 (_IO_fileno (result), fd,
90 (result->_flags2 & _IO_FLAGS2_CLOEXEC) != 0
91 ? O_CLOEXEC : 0);
92#else
93# define newfd 1
94#endif
95
96#ifndef __ASSUME_DUP3
97 if (newfd < 0)
98 {
99 if (errno == ENOSYS)
100 __have_dup3 = -1;
101
102 __dup2 (_IO_fileno (result), fd);
103 if ((result->_flags2 & _IO_FLAGS2_CLOEXEC) != 0)
104 __fcntl (fd, F_SETFD, FD_CLOEXEC);
105 }
106#endif
107 __close (_IO_fileno (result));
108 _IO_fileno (result) = fd;
109 }
110 }
111 else if (fd != -1)
112 __close (fd);
113 if (filename == NULL)
114 free ((char *) gfilename);
115
116 _IO_release_lock (fp);
117 return result;
118}
119