1 /* Copyright (C) 1993-2022 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 <shlib-compat.h>
28 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_1)
29
30 #define _IO_USE_OLD_IO_FILE
31 #include <stdlib.h>
32 #include "libioP.h"
33 #include <fcntl.h>
34
35 FILE *
36 attribute_compat_text_section
_IO_old_fdopen(int fd,const char * mode)37 _IO_old_fdopen (int fd, const char *mode)
38 {
39 int read_write;
40 int posix_mode = 0;
41 struct locked_FILE
42 {
43 struct _IO_FILE_complete_plus fp;
44 #ifdef _IO_MTSAFE_IO
45 _IO_lock_t lock;
46 #endif
47 } *new_f;
48 int fd_flags;
49
50 switch (*mode++)
51 {
52 case 'r':
53 read_write = _IO_NO_WRITES;
54 break;
55 case 'w':
56 read_write = _IO_NO_READS;
57 break;
58 case 'a':
59 posix_mode = O_APPEND;
60 read_write = _IO_NO_READS|_IO_IS_APPENDING;
61 break;
62 default:
63 __set_errno (EINVAL);
64 return NULL;
65 }
66 if (mode[0] == '+' || (mode[0] == 'b' && mode[1] == '+'))
67 read_write &= _IO_IS_APPENDING;
68 fd_flags = __fcntl (fd, F_GETFL);
69 if (fd_flags == -1
70 || ((fd_flags & O_ACCMODE) == O_RDONLY && !(read_write & _IO_NO_WRITES))
71 || ((fd_flags & O_ACCMODE) == O_WRONLY && !(read_write & _IO_NO_READS)))
72 return NULL;
73
74 /* The May 93 draft of P1003.4/D14.1 (redesignated as 1003.1b)
75 [System Application Program Interface (API) Amendment 1:
76 Realtime Extensions], Rationale B.8.3.3
77 Open a Stream on a File Descriptor says:
78
79 Although not explicitly required by POSIX.1, a good
80 implementation of append ("a") mode would cause the
81 O_APPEND flag to be set.
82
83 (Historical implementations [such as Solaris2] do a one-time
84 seek in fdopen.)
85
86 However, we do not turn O_APPEND off if the mode is "w" (even
87 though that would seem consistent) because that would be more
88 likely to break historical programs.
89 */
90 if ((posix_mode & O_APPEND) && !(fd_flags & O_APPEND))
91 {
92 if (__fcntl (fd, F_SETFL, fd_flags | O_APPEND) == -1)
93 return NULL;
94 }
95
96 new_f = (struct locked_FILE *) malloc (sizeof (struct locked_FILE));
97 if (new_f == NULL)
98 return NULL;
99 #ifdef _IO_MTSAFE_IO
100 new_f->fp.file._file._lock = &new_f->lock;
101 #endif
102 _IO_old_init (&new_f->fp.file._file, 0);
103 _IO_JUMPS_FILE_plus (&new_f->fp) = &_IO_old_file_jumps;
104 _IO_old_file_init_internal ((struct _IO_FILE_plus *) &new_f->fp);
105 if (_IO_old_file_attach (&new_f->fp.file._file, fd) == NULL)
106 {
107 _IO_un_link ((struct _IO_FILE_plus *) &new_f->fp);
108 free (new_f);
109 return NULL;
110 }
111 new_f->fp.file._file._flags &= ~_IO_DELETE_DONT_CLOSE;
112
113 _IO_mask_flags (&new_f->fp.file._file, read_write,
114 _IO_NO_READS+_IO_NO_WRITES+_IO_IS_APPENDING);
115
116 return (FILE *) &new_f->fp;
117 }
118
119 strong_alias (_IO_old_fdopen, __old_fdopen)
120 compat_symbol (libc, _IO_old_fdopen, _IO_fdopen, GLIBC_2_0);
121 compat_symbol (libc, __old_fdopen, fdopen, GLIBC_2_0);
122
123 #endif
124