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[glibc.git] / libio / iofdopen.c
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1 /* Copyright (C) 1993,1994,1997-1999,2000,2002 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
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.
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.
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, write to the Free
16 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
17 02111-1307 USA.
19 As a special exception, if you link the code in this file with
20 files compiled with a GNU compiler to produce an executable,
21 that does not cause the resulting executable to be covered by
22 the GNU Lesser General Public License. This exception does not
23 however invalidate any other reasons why the executable file
24 might be covered by the GNU Lesser General Public License.
25 This exception applies to code released by its copyright holders
26 in files containing the exception. */
28 #ifdef __STDC__
29 # include <stdlib.h>
30 #endif
31 #include "libioP.h"
32 #include <fcntl.h>
34 #ifdef _LIBC
35 # include <shlib-compat.h>
36 #endif
38 #ifndef _IO_fcntl
39 #ifdef _LIBC
40 #define _IO_fcntl __fcntl
41 #else
42 #define _IO_fcntl fcntl
43 #endif
44 #endif
46 _IO_FILE *
47 _IO_new_fdopen (fd, mode)
48 int fd;
49 const char *mode;
51 int read_write;
52 int posix_mode = 0;
53 struct locked_FILE
55 struct _IO_FILE_plus fp;
56 #ifdef _IO_MTSAFE_IO
57 _IO_lock_t lock;
58 #endif
59 struct _IO_wide_data wd;
60 } *new_f;
61 int fd_flags;
62 int i;
63 int use_mmap = 0;
65 switch (*mode)
67 case 'r':
68 read_write = _IO_NO_WRITES;
69 break;
70 case 'w':
71 read_write = _IO_NO_READS;
72 break;
73 case 'a':
74 posix_mode = O_APPEND;
75 read_write = _IO_NO_READS|_IO_IS_APPENDING;
76 break;
77 default:
78 MAYBE_SET_EINVAL;
79 return NULL;
81 for (i = 1; i < 5; ++i)
83 switch (*++mode)
85 case '\0':
86 break;
87 case '+':
88 read_write &= _IO_IS_APPENDING;
89 break;
90 case 'm':
91 use_mmap = 1;
92 continue;
93 case 'x':
94 case 'b':
95 default:
96 /* Ignore */
97 continue;
99 break;
101 #ifdef F_GETFL
102 fd_flags = _IO_fcntl (fd, F_GETFL);
103 #ifndef O_ACCMODE
104 #define O_ACCMODE (O_RDONLY|O_WRONLY|O_RDWR)
105 #endif
106 if (fd_flags == -1)
107 return NULL;
109 if (((fd_flags & O_ACCMODE) == O_RDONLY && !(read_write & _IO_NO_WRITES))
110 || ((fd_flags & O_ACCMODE) == O_WRONLY && !(read_write & _IO_NO_READS)))
112 MAYBE_SET_EINVAL;
113 return NULL;
116 /* The May 93 draft of P1003.4/D14.1 (redesignated as 1003.1b)
117 [System Application Program Interface (API) Amendment 1:
118 Realtime Extensions], Rationale B.8.3.3
119 Open a Stream on a File Descriptor says:
121 Although not explicitly required by POSIX.1, a good
122 implementation of append ("a") mode would cause the
123 O_APPEND flag to be set.
125 (Historical implementations [such as Solaris2] do a one-time
126 seek in fdopen.)
128 However, we do not turn O_APPEND off if the mode is "w" (even
129 though that would seem consistent) because that would be more
130 likely to break historical programs.
132 if ((posix_mode & O_APPEND) && !(fd_flags & O_APPEND))
134 #ifdef F_SETFL
135 if (_IO_fcntl (fd, F_SETFL, fd_flags | O_APPEND) == -1)
136 #endif
137 return NULL;
139 #endif
141 new_f = (struct locked_FILE *) malloc (sizeof (struct locked_FILE));
142 if (new_f == NULL)
143 return NULL;
144 #ifdef _IO_MTSAFE_IO
145 new_f->fp.file._lock = &new_f->lock;
146 #endif
147 /* Set up initially to use the `maybe_mmap' jump tables rather than using
148 __fopen_maybe_mmap to do it, because we need them in place before we
149 call _IO_file_attach or else it will allocate a buffer immediately. */
150 _IO_no_init (&new_f->fp.file, 0, 0, &new_f->wd,
151 #ifdef _G_HAVE_MMAP
152 (use_mmap && (read_write & _IO_NO_WRITES))
153 ? &_IO_wfile_jumps_maybe_mmap :
154 #endif
155 &INTUSE(_IO_wfile_jumps));
156 _IO_JUMPS (&new_f->fp) =
157 #ifdef _G_HAVE_MMAP
158 (use_mmap && (read_write & _IO_NO_WRITES)) ? &_IO_file_jumps_maybe_mmap :
159 #endif
160 &INTUSE(_IO_file_jumps);
161 INTUSE(_IO_file_init) (&new_f->fp);
162 #if !_IO_UNIFIED_JUMPTABLES
163 new_f->fp.vtable = NULL;
164 #endif
165 if (INTUSE(_IO_file_attach) ((_IO_FILE *) &new_f->fp, fd) == NULL)
167 INTUSE(_IO_setb) (&new_f->fp.file, NULL, NULL, 0);
168 INTUSE(_IO_un_link) (&new_f->fp);
169 free (new_f);
170 return NULL;
172 new_f->fp.file._flags &= ~_IO_DELETE_DONT_CLOSE;
174 new_f->fp.file._IO_file_flags =
175 _IO_mask_flags (&new_f->fp.file, read_write,
176 _IO_NO_READS+_IO_NO_WRITES+_IO_IS_APPENDING);
178 return &new_f->fp.file;
180 INTDEF2(_IO_new_fdopen, _IO_fdopen)
182 strong_alias (_IO_new_fdopen, __new_fdopen)
183 versioned_symbol (libc, _IO_new_fdopen, _IO_fdopen, GLIBC_2_1);
184 versioned_symbol (libc, __new_fdopen, fdopen, GLIBC_2_1);