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1 | /* Copyright (C) 1993-2024 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 | <https://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 <stdio.h> | |
28 | #include <fcntl.h> | |
29 | #include <stdlib.h> | |
30 | #include <unistd.h> | |
31 | ||
32 | #include <libioP.h> | |
33 | #include <fd_to_filename.h> | |
34 | #include <shlib-compat.h> | |
35 | ||
36 | FILE * | |
37 | freopen (const char *filename, const char *mode, FILE *fp) | |
38 | { | |
39 | FILE *result = NULL; | |
40 | struct fd_to_filename fdfilename; | |
41 | ||
42 | CHECK_FILE (fp, NULL); | |
43 | ||
44 | _IO_acquire_lock (fp); | |
45 | /* First flush the stream (failure should be ignored). */ | |
46 | _IO_SYNC (fp); | |
47 | ||
48 | if (!(fp->_flags & _IO_IS_FILEBUF)) | |
49 | goto end; | |
50 | ||
51 | int fd = _IO_fileno (fp); | |
52 | const char *gfilename | |
53 | = filename != NULL ? filename : __fd_to_filename (fd, &fdfilename); | |
54 | ||
55 | fp->_flags2 |= _IO_FLAGS2_NOCLOSE; | |
56 | #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_1) | |
57 | if (&_IO_stdin_used == NULL) | |
58 | { | |
59 | /* If the shared C library is used by the application binary which | |
60 | was linked against the older version of libio, we just use the | |
61 | older one even for internal use to avoid trouble since a pointer | |
62 | to the old libio may be passed into shared C library and wind | |
63 | up here. */ | |
64 | _IO_old_file_close_it (fp); | |
65 | _IO_JUMPS_FUNC_UPDATE (fp, &_IO_old_file_jumps); | |
66 | result = _IO_old_file_fopen (fp, gfilename, mode); | |
67 | } | |
68 | else | |
69 | #endif | |
70 | { | |
71 | _IO_file_close_it (fp); | |
72 | _IO_JUMPS_FILE_plus (fp) = &_IO_file_jumps; | |
73 | if (_IO_vtable_offset (fp) == 0 && fp->_wide_data != NULL) | |
74 | fp->_wide_data->_wide_vtable = &_IO_wfile_jumps; | |
75 | result = _IO_file_fopen (fp, gfilename, mode, 1); | |
76 | if (result != NULL) | |
77 | result = __fopen_maybe_mmap (result); | |
78 | } | |
79 | fp->_flags2 &= ~_IO_FLAGS2_NOCLOSE; | |
80 | if (result != NULL) | |
81 | { | |
82 | /* unbound stream orientation */ | |
83 | result->_mode = 0; | |
84 | ||
85 | if (fd != -1 && _IO_fileno (result) != fd) | |
86 | { | |
87 | /* At this point we have both file descriptors already allocated, | |
88 | so __dup3 will not fail with EBADF, EINVAL, or EMFILE. But | |
89 | we still need to check for EINVAL and, due Linux internal | |
90 | implementation, EBUSY. It is because on how it internally opens | |
91 | the file by splitting the buffer allocation operation and VFS | |
92 | opening (a dup operation may run when a file is still pending | |
93 | 'install' on VFS). */ | |
94 | if (__dup3 (_IO_fileno (result), fd, | |
95 | (result->_flags2 & _IO_FLAGS2_CLOEXEC) != 0 | |
96 | ? O_CLOEXEC : 0) == -1) | |
97 | { | |
98 | _IO_file_close_it (result); | |
99 | result = NULL; | |
100 | goto end; | |
101 | } | |
102 | __close (_IO_fileno (result)); | |
103 | _IO_fileno (result) = fd; | |
104 | } | |
105 | } | |
106 | else if (fd != -1) | |
107 | __close (fd); | |
108 | ||
109 | end: | |
110 | _IO_release_lock (fp); | |
111 | return result; | |
112 | } |