1/* Copyright (C) 1993-2016 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 <stdlib.h>
28#include "libioP.h"
29#include <fcntl.h>
30
31#ifdef _LIBC
32# include <shlib-compat.h>
33#endif
34
35#ifndef _IO_fcntl
36#ifdef _LIBC
37#define _IO_fcntl __fcntl
38#else
39#define _IO_fcntl fcntl
40#endif
41#endif
42
43_IO_FILE *
44_IO_new_fdopen (int fd, const char *mode)
45{
46 int read_write;
47 struct locked_FILE
48 {
49 struct _IO_FILE_plus fp;
50#ifdef _IO_MTSAFE_IO
51 _IO_lock_t lock;
52#endif
53 struct _IO_wide_data wd;
54 } *new_f;
55 int i;
56 int use_mmap = 0;
57
58 /* Decide whether we modify the offset of the file we attach to and seek to
59 the end of file. We only do this if the mode is 'a' and if the file
60 descriptor did not have O_APPEND in its flags already. */
61 bool do_seek = false;
62
63 switch (*mode)
64 {
65 case 'r':
66 read_write = _IO_NO_WRITES;
67 break;
68 case 'w':
69 read_write = _IO_NO_READS;
70 break;
71 case 'a':
72 read_write = _IO_NO_READS|_IO_IS_APPENDING;
73 break;
74 default:
75 MAYBE_SET_EINVAL;
76 return NULL;
77 }
78 for (i = 1; i < 5; ++i)
79 {
80 switch (*++mode)
81 {
82 case '\0':
83 break;
84 case '+':
85 read_write &= _IO_IS_APPENDING;
86 break;
87 case 'm':
88 use_mmap = 1;
89 continue;
90 case 'x':
91 case 'b':
92 default:
93 /* Ignore */
94 continue;
95 }
96 break;
97 }
98#ifdef F_GETFL
99 int fd_flags = _IO_fcntl (fd, F_GETFL);
100#ifndef O_ACCMODE
101#define O_ACCMODE (O_RDONLY|O_WRONLY|O_RDWR)
102#endif
103 if (fd_flags == -1)
104 return NULL;
105
106 if (((fd_flags & O_ACCMODE) == O_RDONLY && !(read_write & _IO_NO_WRITES))
107 || ((fd_flags & O_ACCMODE) == O_WRONLY && !(read_write & _IO_NO_READS)))
108 {
109 MAYBE_SET_EINVAL;
110 return NULL;
111 }
112
113 /* The May 93 draft of P1003.4/D14.1 (redesignated as 1003.1b)
114 [System Application Program Interface (API) Amendment 1:
115 Realtime Extensions], Rationale B.8.3.3
116 Open a Stream on a File Descriptor says:
117
118 Although not explicitly required by POSIX.1, a good
119 implementation of append ("a") mode would cause the
120 O_APPEND flag to be set.
121
122 (Historical implementations [such as Solaris2] do a one-time
123 seek in fdopen.)
124
125 However, we do not turn O_APPEND off if the mode is "w" (even
126 though that would seem consistent) because that would be more
127 likely to break historical programs.
128 */
129 if ((read_write & _IO_IS_APPENDING) && !(fd_flags & O_APPEND))
130 {
131 do_seek = true;
132#ifdef F_SETFL
133 if (_IO_fcntl (fd, F_SETFL, fd_flags | O_APPEND) == -1)
134#endif
135 return NULL;
136 }
137#endif
138
139 new_f = (struct locked_FILE *) malloc (sizeof (struct locked_FILE));
140 if (new_f == NULL)
141 return NULL;
142#ifdef _IO_MTSAFE_IO
143 new_f->fp.file._lock = &new_f->lock;
144#endif
145 _IO_no_init (&new_f->fp.file, 0, 0, &new_f->wd,
146#ifdef _G_HAVE_MMAP
147 (use_mmap && (read_write & _IO_NO_WRITES))
148 ? &_IO_wfile_jumps_maybe_mmap :
149#endif
150 &_IO_wfile_jumps);
151 _IO_JUMPS (&new_f->fp) =
152#ifdef _G_HAVE_MMAP
153 (use_mmap && (read_write & _IO_NO_WRITES)) ? &_IO_file_jumps_maybe_mmap :
154#endif
155 &_IO_file_jumps;
156 _IO_file_init (&new_f->fp);
157#if !_IO_UNIFIED_JUMPTABLES
158 new_f->fp.vtable = NULL;
159#endif
160 /* We only need to record the fd because _IO_file_init will have unset the
161 offset. It is important to unset the cached offset because the real
162 offset in the file could change between now and when the handle is
163 activated and we would then mislead ftell into believing that we have a
164 valid offset. */
165 new_f->fp.file._fileno = fd;
166 new_f->fp.file._flags &= ~_IO_DELETE_DONT_CLOSE;
167
168 _IO_mask_flags (&new_f->fp.file, read_write,
169 _IO_NO_READS+_IO_NO_WRITES+_IO_IS_APPENDING);
170
171 /* For append mode, set the file offset to the end of the file if we added
172 O_APPEND to the file descriptor flags. Don't update the offset cache
173 though, since the file handle is not active. */
174 if (do_seek && ((read_write & (_IO_IS_APPENDING | _IO_NO_READS))
175 == (_IO_IS_APPENDING | _IO_NO_READS)))
176 {
177 _IO_off64_t new_pos = _IO_SYSSEEK (&new_f->fp.file, 0, _IO_seek_end);
178 if (new_pos == _IO_pos_BAD && errno != ESPIPE)
179 return NULL;
180 }
181 return &new_f->fp.file;
182}
183libc_hidden_ver (_IO_new_fdopen, _IO_fdopen)
184
185strong_alias (_IO_new_fdopen, __new_fdopen)
186versioned_symbol (libc, _IO_new_fdopen, _IO_fdopen, GLIBC_2_1);
187versioned_symbol (libc, __new_fdopen, fdopen, GLIBC_2_1);
188