1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22 /*
23 * Copyright 2008 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26
27 /* Copyright (c) 1988 AT&T */
28 /* All Rights Reserved */
29
30 /*
31 * University Copyright- Copyright (c) 1982, 1986, 1988
32 * The Regents of the University of California
33 * All Rights Reserved
34 *
35 * University Acknowledgment- Portions of this document are derived from
36 * software developed by the University of California, Berkeley, and its
37 * contributors.
38 */
39
40 #pragma ident "%Z%%M% %I% %E% SMI"
41
42 #include "lint.h"
43 #include "file64.h"
44 #include <sys/types.h>
45 #include <stdio.h>
46 #include <mtlib.h>
47 #include <fcntl.h>
48 #include <unistd.h>
49 #include <limits.h>
50 #include <thread.h>
51 #include <synch.h>
52 #include <stdlib.h>
53 #include <errno.h>
54 #include "stdiom.h"
55 #include "xpg6.h"
56
57 /* Final argument to _endopen depends on build environment */
58 #define LARGE_OPEN (_FILE_OFFSET_BITS == 64)
59
60 FILE *
fopen(const char * name,const char * type)61 fopen(const char *name, const char *type) /* open name, return new stream */
62 {
63 FILE *iop;
64 FILE *rc;
65
66 iop = _findiop();
67 /*
68 * Note that iop is not locked here, since no other thread could
69 * possibly call _endopen with the same iop at this point.
70 */
71 rc = _endopen(name, type, iop, LARGE_OPEN);
72
73 if (rc == NULL && iop != NULL)
74 iop->_flag = 0; /* release iop */
75
76 return (rc);
77 }
78
79 static FILE *
_freopen_null(const char * type,FILE * iop)80 _freopen_null(const char *type, FILE *iop)
81 {
82 char plus, mode;
83 int oflag, nflag, fd, accmode;
84 mbstate_t *mb;
85
86 if (iop == NULL || iop->_flag == 0) {
87 errno = EBADF;
88 return (NULL);
89 }
90
91 if (!(iop->_flag & _IONBF) && (iop->_flag & (_IOWRT | _IOREAD | _IORW)))
92 (void) _fflush_u(iop);
93
94 if (iop->_flag & _IOMYBUF) {
95 free((char *)iop->_base - PUSHBACK);
96 }
97 iop->_base = NULL;
98 iop->_ptr = NULL;
99 /*
100 * Clear stream orientation, clear stream encoding rule, and set
101 * stream's mbstate_t object to describe an initial conversion state.
102 */
103 mb = _getmbstate(iop);
104 if (mb != NULL)
105 (void) memset(mb, 0, sizeof (mbstate_t));
106 iop->_cnt = 0;
107 _setorientation(iop, _NO_MODE);
108
109 fd = FILENO(iop);
110 mode = type[0];
111 if (mode != 'r' && mode != 'w' && mode != 'a') {
112 errno = EINVAL;
113 goto errret;
114 }
115
116 if ((oflag = fcntl(fd, F_GETFL)) == -1)
117 goto errret;
118
119 if ((plus = type[1]) == 'b')
120 plus = type[2];
121
122 /*
123 * Because the filename has not been specified, the underlying file
124 * will not be closed and reopened. The access modes of an open
125 * file descriptor can't be changed via fcntl(). When '+' is
126 * specified, the old access mode needs to be O_RDWR. When 'r' is
127 * specified, the old access mode needs to be O_RDONLY or O_RDWR.
128 * When 'a' or 'w' is specified, the old access mode needs to be
129 * O_WRONLY or O_RDWR. Otherwise, fail with EBADF, indicating that
130 * the underlying file descriptor was not opened with a mode that
131 * would allow the stream to do successful I/O with the requested mode.
132 */
133
134 accmode = oflag & O_ACCMODE;
135 if ((accmode == O_RDONLY && (mode != 'r' || plus == '+')) ||
136 (accmode == O_WRONLY && (mode == 'r' || plus == '+'))) {
137 (void) close(fd);
138 errno = EBADF;
139 goto errret_noclose;
140 }
141
142 #ifdef _LP64
143 iop->_flag &= ~0377; /* clear lower 8-bits */
144 if (mode == 'r') {
145 iop->_flag |= _IOREAD;
146 nflag = oflag & ~O_APPEND;
147 } else if (mode == 'w') {
148 iop->_flag |= _IOWRT;
149 nflag = oflag & ~O_APPEND;
150 } else {
151 iop->_flag |= _IOWRT;
152 nflag = oflag | O_APPEND;
153 }
154 if (plus == '+') {
155 iop->_flag = (iop->_flag & ~(_IOREAD | _IOWRT)) | _IORW;
156 }
157 #else
158 if (mode == 'r') {
159 iop->_flag = _IOREAD;
160 nflag = oflag & ~O_APPEND;
161 } else if (mode == 'w') {
162 iop->_flag = _IOWRT;
163 nflag = oflag & ~O_APPEND;
164 } else {
165 iop->_flag = _IOWRT;
166 nflag = oflag | O_APPEND;
167 }
168 if (plus == '+') {
169 iop->_flag = _IORW;
170 }
171 #endif
172 /*
173 * Change mode of underlying fd as much as possible without closing
174 * and reopening it. Ignore truncate failures, eg. with stdout.
175 */
176 if (mode == 'w')
177 (void) ftruncate64(fd, (off64_t)0);
178
179 if (fcntl(fd, F_SETFL, nflag) == -1)
180 goto errret;
181
182 /* ignore seek failures, eg. with pipes */
183 (void) lseek64(fd, (off64_t)0, SEEK_SET);
184
185 return (iop);
186
187 errret:
188 if (errno != EBADF)
189 (void) close(fd);
190
191 errret_noclose:
192 iop->_flag = 0; /* release iop */
193 return (NULL);
194 }
195
196 FILE *
freopen(const char * name,const char * type,FILE * iop)197 freopen(const char *name, const char *type, FILE *iop)
198 {
199 FILE *rc;
200 rmutex_t *lk;
201
202 if (name == NULL && __xpg6 & _C99SUSv3_freopen_NULL_filename) {
203 /*
204 * XPG6: If name is a null pointer, freopen will attempt to
205 * change the mode of the stream to that specified by type.
206 */
207 FLOCKFILE(lk, iop);
208 rc = _freopen_null(type, iop);
209 FUNLOCKFILE(lk);
210 return (rc);
211 }
212 /*
213 * there may be concurrent calls to reopen the same stream - need
214 * to make freopen() atomic
215 */
216 FLOCKFILE(lk, iop);
217 /*
218 * new function to do everything that fclose() does, except
219 * to release the iop - this cannot yet be released since
220 * _endopen() is yet to be called on this iop
221 */
222
223 (void) close_fd(iop);
224
225 rc = _endopen(name, type, iop, LARGE_OPEN);
226
227 if (rc == NULL)
228 iop->_flag = 0; /* release iop */
229
230 FUNLOCKFILE(lk);
231 return (rc);
232 }
233