1 /* Copyright (C) 2004 Manuel Novoa III <mjn3@codepoet.org>
2 *
3 * GNU Library General Public License (LGPL) version 2 or later.
4 *
5 * Dedicated to Toni. See uClibc/DEDICATION.mjn3 for details.
6 */
7
8 #include "_stdio.h"
9
10
11 /* Function to handle transition to writing.
12 * Initialize or verify the stream's orientation (even if readonly).
13 * Check that the stream is writable.
14 * If currently reading, check that we can transition to writing.
15 * C99 requires that the stream is at EOF, but attempting to
16 * auto-transition via fseek() is a configurable option.
17 * Returns 0 on success and EOF otherwise.
18 *
19 * Notes:
20 * There are two function signatures, depending on wchar support,
21 * since with no wchar support the orientation is narrow by default.
22 */
23
24 #ifdef __UCLIBC_HAS_WCHAR__
__stdio_trans2w_o(FILE * __restrict stream,int oflag)25 int attribute_hidden __stdio_trans2w_o(FILE * __restrict stream, int oflag)
26 #else
27 int attribute_hidden __stdio_trans2w(FILE * __restrict stream)
28 #endif
29 {
30 __STDIO_STREAM_VALIDATE(stream);
31 assert(!__STDIO_STREAM_IS_WRITING(stream));
32
33 #ifdef __UCLIBC_HAS_WCHAR__
34 if (!(stream->__modeflags & oflag)) {
35 if (stream->__modeflags & (__FLAG_NARROW|__FLAG_WIDE)) {
36 __UNDEFINED_OR_NONPORTABLE;
37 goto DO_EBADF;
38 }
39 stream->__modeflags |= oflag;
40 }
41 #endif
42
43 if (stream->__modeflags & __FLAG_READONLY) {
44 #if defined(__UCLIBC_HAS_WCHAR__) || !defined(__UCLIBC_HAS_STDIO_AUTO_RW_TRANSITION__)
45 DO_EBADF:
46 #endif
47 __set_errno(EBADF);
48 #ifdef __UCLIBC_HAS_STDIO_AUTO_RW_TRANSITION__
49 ERROR:
50 #endif
51 __STDIO_STREAM_SET_ERROR(stream);
52 __STDIO_STREAM_VALIDATE(stream);
53 return EOF;
54 }
55
56 if (__STDIO_STREAM_IS_READING(stream)) {
57 if (!__FEOF_UNLOCKED(stream)) {
58 #ifdef __UCLIBC_HAS_STDIO_AUTO_RW_TRANSITION__
59 /* Need to seek to correct position if we have buffered
60 * read data or ungots. If appending, we might as well
61 * seek to the end.
62 *
63 * NOTE: If the OS does not handle append files correctly,
64 * this is insufficient since we would need to seek to
65 * the end even if not reading.*/
66 if (((__STDIO_STREAM_BUFFER_RAVAIL(stream))
67 || (stream->__modeflags & __FLAG_UNGOT))
68 && fseek(stream, 0L,
69 ((stream->__modeflags & __FLAG_APPEND)
70 ? SEEK_END : SEEK_CUR))
71 ) {
72 /* fseek() only sets error indicator on read/write error. */
73 goto ERROR;
74 }
75 #else
76 /* C99 requires either at EOF or currently not reading. */
77 __UNDEFINED_OR_NONPORTABLE;
78 goto DO_EBADF;
79 #endif
80 }
81 __STDIO_STREAM_CLEAR_READING_AND_UNGOTS(stream);
82 __STDIO_STREAM_DISABLE_GETC(stream);
83 /* Reaching EOF does not reset buffer pointers... */
84 __STDIO_STREAM_INIT_BUFREAD_BUFPOS(stream);
85 }
86
87 __STDIO_STREAM_SET_WRITING(stream);
88 if (__STDIO_STREAM_IS_NARROW_FBF(stream)) {
89 __STDIO_STREAM_ENABLE_PUTC(stream);
90 }
91
92 __STDIO_STREAM_VALIDATE(stream);
93 return 0;
94 }
95