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 | } |
183 | libc_hidden_ver (_IO_new_fdopen, _IO_fdopen) |
184 | |
185 | strong_alias (_IO_new_fdopen, __new_fdopen) |
186 | versioned_symbol (libc, _IO_new_fdopen, _IO_fdopen, GLIBC_2_1); |
187 | versioned_symbol (libc, __new_fdopen, fdopen, GLIBC_2_1); |
188 | |