1/*-
2 * Copyright (c) 1990, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Chris Torek.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33#if defined(LIBC_SCCS) && !defined(lint)
34static char sccsid[] = "@(#)freopen.c 8.1 (Berkeley) 6/4/93";
35#endif /* LIBC_SCCS and not lint */
36#include <sys/cdefs.h>
| 1/*-
2 * Copyright (c) 1990, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Chris Torek.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33#if defined(LIBC_SCCS) && !defined(lint)
34static char sccsid[] = "@(#)freopen.c 8.1 (Berkeley) 6/4/93";
35#endif /* LIBC_SCCS and not lint */
36#include <sys/cdefs.h>
|
38
39#include "namespace.h"
40#include <sys/types.h>
41#include <sys/stat.h>
42#include <fcntl.h>
43#include <errno.h>
44#include <limits.h>
45#include <unistd.h>
46#include <stdio.h>
47#include <stdlib.h>
48#include "un-namespace.h"
49#include "libc_private.h"
50#include "local.h"
51
52/*
53 * Re-direct an existing, open (probably) file to some other file.
54 * ANSI is written such that the original file gets closed if at
55 * all possible, no matter what.
56 */
57FILE *
58freopen(const char * __restrict file, const char * __restrict mode,
59 FILE * __restrict fp)
60{
61 int f;
62 int dflags, flags, isopen, oflags, sverrno, wantfd;
63
64 if ((flags = __sflags(mode, &oflags)) == 0) {
65 sverrno = errno;
66 (void) fclose(fp);
67 errno = sverrno;
68 return (NULL);
69 }
70
71 FLOCKFILE(fp);
72
73 if (!__sdidinit)
74 __sinit();
75
76 /*
77 * If the filename is a NULL pointer, the caller is asking us to
78 * re-open the same file with a different mode. We allow this only
79 * if the modes are compatible.
80 */
81 if (file == NULL) {
82 /* See comment below regarding freopen() of closed files. */
83 if (fp->_flags == 0) {
84 FUNLOCKFILE(fp);
85 errno = EINVAL;
86 return (NULL);
87 }
88 if ((dflags = _fcntl(fp->_file, F_GETFL)) < 0) {
89 sverrno = errno;
90 fclose(fp);
91 FUNLOCKFILE(fp);
92 errno = sverrno;
93 return (NULL);
94 }
95 /* Work around incorrect O_ACCMODE. */
96 if ((dflags & O_ACCMODE) != O_RDWR &&
97 (dflags & (O_ACCMODE | O_EXEC)) != (oflags & O_ACCMODE)) {
98 fclose(fp);
99 FUNLOCKFILE(fp);
100 errno = EBADF;
101 return (NULL);
102 }
103 if (fp->_flags & __SWR)
104 (void) __sflush(fp);
105 if ((oflags ^ dflags) & O_APPEND) {
106 dflags &= ~O_APPEND;
107 dflags |= oflags & O_APPEND;
108 if (_fcntl(fp->_file, F_SETFL, dflags) < 0) {
109 sverrno = errno;
110 fclose(fp);
111 FUNLOCKFILE(fp);
112 errno = sverrno;
113 return (NULL);
114 }
115 }
116 if (oflags & O_TRUNC)
117 (void) ftruncate(fp->_file, (off_t)0);
118 if (!(oflags & O_APPEND))
119 (void) _sseek(fp, (fpos_t)0, SEEK_SET);
120 if (oflags & O_CLOEXEC)
121 (void) _fcntl(fp->_file, F_SETFD, FD_CLOEXEC);
122 f = fp->_file;
123 isopen = 0;
124 wantfd = -1;
125 goto finish;
126 }
127
128 /*
129 * There are actually programs that depend on being able to "freopen"
130 * descriptors that weren't originally open. Keep this from breaking.
131 * Remember whether the stream was open to begin with, and which file
132 * descriptor (if any) was associated with it. If it was attached to
133 * a descriptor, defer closing it; freopen("/dev/stdin", "r", stdin)
134 * should work. This is unnecessary if it was not a Unix file.
135 */
136 if (fp->_flags == 0) {
137 fp->_flags = __SEOF; /* hold on to it */
138 isopen = 0;
139 wantfd = -1;
140 } else {
141 /* flush the stream; ANSI doesn't require this. */
142 if (fp->_flags & __SWR)
143 (void) __sflush(fp);
144 /* if close is NULL, closing is a no-op, hence pointless */
145 isopen = fp->_close != NULL;
146 if ((wantfd = fp->_file) < 0 && isopen) {
147 (void) (*fp->_close)(fp->_cookie);
148 isopen = 0;
149 }
150 }
151
152 /* Get a new descriptor to refer to the new file. */
153 f = _open(file, oflags, DEFFILEMODE);
154 /* If out of fd's close the old one and try again. */
155 if (f < 0 && isopen && wantfd > STDERR_FILENO &&
156 (errno == ENFILE || errno == EMFILE)) {
157 (void) (*fp->_close)(fp->_cookie);
158 isopen = 0;
159 wantfd = -1;
160 f = _open(file, oflags, DEFFILEMODE);
161 }
162 sverrno = errno;
163
164finish:
165 /*
166 * Finish closing fp. Even if the open succeeded above, we cannot
167 * keep fp->_base: it may be the wrong size. This loses the effect
168 * of any setbuffer calls, but stdio has always done this before.
169 *
170 * Leave the existing file descriptor open until dup2() is called
171 * below to avoid races where a concurrent open() in another thread
172 * could claim the existing descriptor.
173 */
174 if (fp->_flags & __SMBF)
175 free((char *)fp->_bf._base);
176 fp->_w = 0;
177 fp->_r = 0;
178 fp->_p = NULL;
179 fp->_bf._base = NULL;
180 fp->_bf._size = 0;
181 fp->_lbfsize = 0;
182 if (HASUB(fp))
183 FREEUB(fp);
184 fp->_ub._size = 0;
185 if (HASLB(fp))
186 FREELB(fp);
187 fp->_lb._size = 0;
188 fp->_orientation = 0;
189 memset(&fp->_mbstate, 0, sizeof(mbstate_t));
190
191 if (f < 0) { /* did not get it after all */
192 if (isopen)
193 (void) (*fp->_close)(fp->_cookie);
194 fp->_flags = 0; /* set it free */
195 FUNLOCKFILE(fp);
196 errno = sverrno; /* restore in case _close clobbered */
197 return (NULL);
198 }
199
200 /*
201 * If reopening something that was open before on a real file, try
202 * to maintain the descriptor. Various C library routines (perror)
203 * assume stderr is always fd STDERR_FILENO, even if being freopen'd.
204 */
205 if (wantfd >= 0) {
206 if ((oflags & O_CLOEXEC ? _fcntl(f, F_DUP2FD_CLOEXEC, wantfd) :
207 _dup2(f, wantfd)) >= 0) {
208 (void)_close(f);
209 f = wantfd;
210 } else
211 (void)_close(fp->_file);
212 }
213
214 /*
215 * File descriptors are a full int, but _file is only a short.
216 * If we get a valid file descriptor that is greater than
217 * SHRT_MAX, then the fd will get sign-extended into an
218 * invalid file descriptor. Handle this case by failing the
219 * open.
220 */
221 if (f > SHRT_MAX) {
222 fp->_flags = 0; /* set it free */
223 FUNLOCKFILE(fp);
224 errno = EMFILE;
225 return (NULL);
226 }
227
228 fp->_flags = flags;
229 fp->_file = f;
230 fp->_cookie = fp;
231 fp->_read = __sread;
232 fp->_write = __swrite;
233 fp->_seek = __sseek;
234 fp->_close = __sclose;
235 /*
236 * When opening in append mode, even though we use O_APPEND,
237 * we need to seek to the end so that ftell() gets the right
238 * answer. If the user then alters the seek pointer, or
239 * the file extends, this will fail, but there is not much
240 * we can do about this. (We could set __SAPP and check in
241 * fseek and ftell.)
242 */
| 38
39#include "namespace.h"
40#include <sys/types.h>
41#include <sys/stat.h>
42#include <fcntl.h>
43#include <errno.h>
44#include <limits.h>
45#include <unistd.h>
46#include <stdio.h>
47#include <stdlib.h>
48#include "un-namespace.h"
49#include "libc_private.h"
50#include "local.h"
51
52/*
53 * Re-direct an existing, open (probably) file to some other file.
54 * ANSI is written such that the original file gets closed if at
55 * all possible, no matter what.
56 */
57FILE *
58freopen(const char * __restrict file, const char * __restrict mode,
59 FILE * __restrict fp)
60{
61 int f;
62 int dflags, flags, isopen, oflags, sverrno, wantfd;
63
64 if ((flags = __sflags(mode, &oflags)) == 0) {
65 sverrno = errno;
66 (void) fclose(fp);
67 errno = sverrno;
68 return (NULL);
69 }
70
71 FLOCKFILE(fp);
72
73 if (!__sdidinit)
74 __sinit();
75
76 /*
77 * If the filename is a NULL pointer, the caller is asking us to
78 * re-open the same file with a different mode. We allow this only
79 * if the modes are compatible.
80 */
81 if (file == NULL) {
82 /* See comment below regarding freopen() of closed files. */
83 if (fp->_flags == 0) {
84 FUNLOCKFILE(fp);
85 errno = EINVAL;
86 return (NULL);
87 }
88 if ((dflags = _fcntl(fp->_file, F_GETFL)) < 0) {
89 sverrno = errno;
90 fclose(fp);
91 FUNLOCKFILE(fp);
92 errno = sverrno;
93 return (NULL);
94 }
95 /* Work around incorrect O_ACCMODE. */
96 if ((dflags & O_ACCMODE) != O_RDWR &&
97 (dflags & (O_ACCMODE | O_EXEC)) != (oflags & O_ACCMODE)) {
98 fclose(fp);
99 FUNLOCKFILE(fp);
100 errno = EBADF;
101 return (NULL);
102 }
103 if (fp->_flags & __SWR)
104 (void) __sflush(fp);
105 if ((oflags ^ dflags) & O_APPEND) {
106 dflags &= ~O_APPEND;
107 dflags |= oflags & O_APPEND;
108 if (_fcntl(fp->_file, F_SETFL, dflags) < 0) {
109 sverrno = errno;
110 fclose(fp);
111 FUNLOCKFILE(fp);
112 errno = sverrno;
113 return (NULL);
114 }
115 }
116 if (oflags & O_TRUNC)
117 (void) ftruncate(fp->_file, (off_t)0);
118 if (!(oflags & O_APPEND))
119 (void) _sseek(fp, (fpos_t)0, SEEK_SET);
120 if (oflags & O_CLOEXEC)
121 (void) _fcntl(fp->_file, F_SETFD, FD_CLOEXEC);
122 f = fp->_file;
123 isopen = 0;
124 wantfd = -1;
125 goto finish;
126 }
127
128 /*
129 * There are actually programs that depend on being able to "freopen"
130 * descriptors that weren't originally open. Keep this from breaking.
131 * Remember whether the stream was open to begin with, and which file
132 * descriptor (if any) was associated with it. If it was attached to
133 * a descriptor, defer closing it; freopen("/dev/stdin", "r", stdin)
134 * should work. This is unnecessary if it was not a Unix file.
135 */
136 if (fp->_flags == 0) {
137 fp->_flags = __SEOF; /* hold on to it */
138 isopen = 0;
139 wantfd = -1;
140 } else {
141 /* flush the stream; ANSI doesn't require this. */
142 if (fp->_flags & __SWR)
143 (void) __sflush(fp);
144 /* if close is NULL, closing is a no-op, hence pointless */
145 isopen = fp->_close != NULL;
146 if ((wantfd = fp->_file) < 0 && isopen) {
147 (void) (*fp->_close)(fp->_cookie);
148 isopen = 0;
149 }
150 }
151
152 /* Get a new descriptor to refer to the new file. */
153 f = _open(file, oflags, DEFFILEMODE);
154 /* If out of fd's close the old one and try again. */
155 if (f < 0 && isopen && wantfd > STDERR_FILENO &&
156 (errno == ENFILE || errno == EMFILE)) {
157 (void) (*fp->_close)(fp->_cookie);
158 isopen = 0;
159 wantfd = -1;
160 f = _open(file, oflags, DEFFILEMODE);
161 }
162 sverrno = errno;
163
164finish:
165 /*
166 * Finish closing fp. Even if the open succeeded above, we cannot
167 * keep fp->_base: it may be the wrong size. This loses the effect
168 * of any setbuffer calls, but stdio has always done this before.
169 *
170 * Leave the existing file descriptor open until dup2() is called
171 * below to avoid races where a concurrent open() in another thread
172 * could claim the existing descriptor.
173 */
174 if (fp->_flags & __SMBF)
175 free((char *)fp->_bf._base);
176 fp->_w = 0;
177 fp->_r = 0;
178 fp->_p = NULL;
179 fp->_bf._base = NULL;
180 fp->_bf._size = 0;
181 fp->_lbfsize = 0;
182 if (HASUB(fp))
183 FREEUB(fp);
184 fp->_ub._size = 0;
185 if (HASLB(fp))
186 FREELB(fp);
187 fp->_lb._size = 0;
188 fp->_orientation = 0;
189 memset(&fp->_mbstate, 0, sizeof(mbstate_t));
190
191 if (f < 0) { /* did not get it after all */
192 if (isopen)
193 (void) (*fp->_close)(fp->_cookie);
194 fp->_flags = 0; /* set it free */
195 FUNLOCKFILE(fp);
196 errno = sverrno; /* restore in case _close clobbered */
197 return (NULL);
198 }
199
200 /*
201 * If reopening something that was open before on a real file, try
202 * to maintain the descriptor. Various C library routines (perror)
203 * assume stderr is always fd STDERR_FILENO, even if being freopen'd.
204 */
205 if (wantfd >= 0) {
206 if ((oflags & O_CLOEXEC ? _fcntl(f, F_DUP2FD_CLOEXEC, wantfd) :
207 _dup2(f, wantfd)) >= 0) {
208 (void)_close(f);
209 f = wantfd;
210 } else
211 (void)_close(fp->_file);
212 }
213
214 /*
215 * File descriptors are a full int, but _file is only a short.
216 * If we get a valid file descriptor that is greater than
217 * SHRT_MAX, then the fd will get sign-extended into an
218 * invalid file descriptor. Handle this case by failing the
219 * open.
220 */
221 if (f > SHRT_MAX) {
222 fp->_flags = 0; /* set it free */
223 FUNLOCKFILE(fp);
224 errno = EMFILE;
225 return (NULL);
226 }
227
228 fp->_flags = flags;
229 fp->_file = f;
230 fp->_cookie = fp;
231 fp->_read = __sread;
232 fp->_write = __swrite;
233 fp->_seek = __sseek;
234 fp->_close = __sclose;
235 /*
236 * When opening in append mode, even though we use O_APPEND,
237 * we need to seek to the end so that ftell() gets the right
238 * answer. If the user then alters the seek pointer, or
239 * the file extends, this will fail, but there is not much
240 * we can do about this. (We could set __SAPP and check in
241 * fseek and ftell.)
242 */
|