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. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 */
36
37#if defined(LIBC_SCCS) && !defined(lint)
38#if 0
39static char sccsid[] = "@(#)fseek.c 8.3 (Berkeley) 1/2/94";
40#endif
41static const char rcsid[] =
| 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. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 */
36
37#if defined(LIBC_SCCS) && !defined(lint)
38#if 0
39static char sccsid[] = "@(#)fseek.c 8.3 (Berkeley) 1/2/94";
40#endif
41static const char rcsid[] =
|
42 "$FreeBSD: head/lib/libc/stdio/fseek.c 82742 2001-09-01 15:01:37Z ache $";
| 42 "$FreeBSD: head/lib/libc/stdio/fseek.c 82743 2001-09-01 15:28:24Z ache $";
|
43#endif /* LIBC_SCCS and not lint */
44
45#include "namespace.h"
46#include <sys/types.h>
47#include <sys/stat.h>
48#include <errno.h>
49#include <fcntl.h>
50#include <limits.h>
51#include <stdio.h>
52#include <stdlib.h>
53#include "un-namespace.h"
54#include "local.h"
55#include "libc_private.h"
56
57#define POS_ERR (-(fpos_t)1)
58
59int
60fseek(fp, offset, whence)
61 register FILE *fp;
62 long offset;
63 int whence;
64{
65 int ret;
| 43#endif /* LIBC_SCCS and not lint */
44
45#include "namespace.h"
46#include <sys/types.h>
47#include <sys/stat.h>
48#include <errno.h>
49#include <fcntl.h>
50#include <limits.h>
51#include <stdio.h>
52#include <stdlib.h>
53#include "un-namespace.h"
54#include "local.h"
55#include "libc_private.h"
56
57#define POS_ERR (-(fpos_t)1)
58
59int
60fseek(fp, offset, whence)
61 register FILE *fp;
62 long offset;
63 int whence;
64{
65 int ret;
|
| 66 int serrno = errno;
|
66
67 /* make sure stdio is set up */
68 if (!__sdidinit)
69 __sinit();
70
71 FLOCKFILE(fp);
72 ret = _fseeko(fp, (off_t)offset, whence, 1);
73 FUNLOCKFILE(fp);
| 67
68 /* make sure stdio is set up */
69 if (!__sdidinit)
70 __sinit();
71
72 FLOCKFILE(fp);
73 ret = _fseeko(fp, (off_t)offset, whence, 1);
74 FUNLOCKFILE(fp);
|
| 75 if (ret == 0)
76 errno = serrno;
|
74 return (ret);
75}
76
77int
78fseeko(fp, offset, whence)
79 FILE *fp;
80 off_t offset;
81 int whence;
82{
83 int ret;
| 77 return (ret);
78}
79
80int
81fseeko(fp, offset, whence)
82 FILE *fp;
83 off_t offset;
84 int whence;
85{
86 int ret;
|
| 87 int serrno = errno;
|
84
85 /* make sure stdio is set up */
86 if (!__sdidinit)
87 __sinit();
88
89 FLOCKFILE(fp);
90 ret = _fseeko(fp, offset, whence, 0);
91 FUNLOCKFILE(fp);
| 88
89 /* make sure stdio is set up */
90 if (!__sdidinit)
91 __sinit();
92
93 FLOCKFILE(fp);
94 ret = _fseeko(fp, offset, whence, 0);
95 FUNLOCKFILE(fp);
|
| 96 if (ret == 0)
97 errno = serrno;
|
92 return (ret);
93}
94
95/*
96 * Seek the given file to the given offset.
97 * `Whence' must be one of the three SEEK_* macros.
98 */
99int
100_fseeko(fp, offset, whence, ltest)
101 FILE *fp;
102 off_t offset;
103 int whence;
104 int ltest;
105{
106 register fpos_t (*seekfn) __P((void *, fpos_t, int));
107 fpos_t target, curoff;
108 size_t n;
109 struct stat st;
110 int havepos;
111
112 /*
113 * Have to be able to seek.
114 */
115 if ((seekfn = fp->_seek) == NULL) {
116 errno = ESPIPE; /* historic practice */
117 return (-1);
118 }
119
120 /*
121 * Change any SEEK_CUR to SEEK_SET, and check `whence' argument.
122 * After this, whence is either SEEK_SET or SEEK_END.
123 */
124 switch (whence) {
125
126 case SEEK_CUR:
127 /*
128 * In order to seek relative to the current stream offset,
129 * we have to first find the current stream offset via
130 * ftell (see ftell for details).
131 */
132 if (_ftello(fp, &curoff))
133 return (-1);
134 if (curoff < 0) {
135 /* Unspecified position because of ungetc() at 0 */
136 errno = ESPIPE;
137 return (-1);
138 }
139 if (offset > 0 && curoff > OFF_MAX - offset) {
140 errno = EOVERFLOW;
141 return (-1);
142 }
143 offset += curoff;
144 if (offset < 0) {
145 errno = EINVAL;
146 return (-1);
147 }
148 if (ltest && offset > LONG_MAX) {
149 errno = EOVERFLOW;
150 return (-1);
151 }
152 whence = SEEK_SET;
153 havepos = 1;
154 break;
155
156 case SEEK_SET:
157 if (offset < 0) {
158 errno = EINVAL;
159 return (-1);
160 }
161 case SEEK_END:
162 curoff = 0; /* XXX just to keep gcc quiet */
163 havepos = 0;
164 break;
165
166 default:
167 errno = EINVAL;
168 return (-1);
169 }
170
171 /*
172 * Can only optimise if:
173 * reading (and not reading-and-writing);
174 * not unbuffered; and
175 * this is a `regular' Unix file (and hence seekfn==__sseek).
176 * We must check __NBF first, because it is possible to have __NBF
177 * and __SOPT both set.
178 */
179 if (fp->_bf._base == NULL)
180 __smakebuf(fp);
181 if (fp->_flags & (__SWR | __SRW | __SNBF | __SNPT))
182 goto dumb;
183 if ((fp->_flags & __SOPT) == 0) {
184 if (seekfn != __sseek ||
185 fp->_file < 0 || _fstat(fp->_file, &st) ||
186 (st.st_mode & S_IFMT) != S_IFREG) {
187 fp->_flags |= __SNPT;
188 goto dumb;
189 }
190 fp->_blksize = st.st_blksize;
191 fp->_flags |= __SOPT;
192 }
193
194 /*
195 * We are reading; we can try to optimise.
196 * Figure out where we are going and where we are now.
197 */
198 if (whence == SEEK_SET)
199 target = offset;
200 else {
201 if (_fstat(fp->_file, &st))
202 goto dumb;
203 if (offset > 0 && st.st_size > OFF_MAX - offset) {
204 errno = EOVERFLOW;
205 return (-1);
206 }
207 target = st.st_size + offset;
208 if ((off_t)target < 0) {
209 errno = EINVAL;
210 return (-1);
211 }
212 if (ltest && (off_t)target > LONG_MAX) {
213 errno = EOVERFLOW;
214 return (-1);
215 }
216 }
217
218 if (!havepos && _ftello(fp, &curoff))
219 goto dumb;
220
221 /*
222 * (If the buffer was modified, we have to
223 * skip this; see fgetln.c.)
224 */
225 if (fp->_flags & __SMOD)
226 goto abspos;
227
228 /*
229 * Compute the number of bytes in the input buffer (pretending
230 * that any ungetc() input has been discarded). Adjust current
231 * offset backwards by this count so that it represents the
232 * file offset for the first byte in the current input buffer.
233 */
234 if (HASUB(fp)) {
235 curoff += fp->_r; /* kill off ungetc */
236 n = fp->_extra->_up - fp->_bf._base;
237 curoff -= n;
238 n += fp->_ur;
239 } else {
240 n = fp->_p - fp->_bf._base;
241 curoff -= n;
242 n += fp->_r;
243 }
244
245 /*
246 * If the target offset is within the current buffer,
247 * simply adjust the pointers, clear EOF, undo ungetc(),
248 * and return.
249 */
250 if (target >= curoff && target < curoff + n) {
251 size_t o = target - curoff;
252
253 fp->_p = fp->_bf._base + o;
254 fp->_r = n - o;
255 if (HASUB(fp))
256 FREEUB(fp);
257 fp->_flags &= ~__SEOF;
258 return (0);
259 }
260
261abspos:
262 /*
263 * The place we want to get to is not within the current buffer,
264 * but we can still be kind to the kernel copyout mechanism.
265 * By aligning the file offset to a block boundary, we can let
266 * the kernel use the VM hardware to map pages instead of
267 * copying bytes laboriously. Using a block boundary also
268 * ensures that we only read one block, rather than two.
269 */
270 curoff = target & ~(fp->_blksize - 1);
271 if ((*seekfn)(fp->_cookie, curoff, SEEK_SET) == POS_ERR)
272 goto dumb;
273 fp->_r = 0;
274 fp->_p = fp->_bf._base;
275 if (HASUB(fp))
276 FREEUB(fp);
277 n = target - curoff;
278 if (n) {
279 if (__srefill(fp) || fp->_r < n)
280 goto dumb;
281 fp->_p += n;
282 fp->_r -= n;
283 }
284 fp->_flags &= ~__SEOF;
285 return (0);
286
287 /*
288 * We get here if we cannot optimise the seek ... just
289 * do it. Allow the seek function to change fp->_bf._base.
290 */
291dumb:
292 if (__sflush(fp) ||
293 (*seekfn)(fp->_cookie, (fpos_t)offset, whence) == POS_ERR)
294 return (-1);
295 if (ltest && fp->_offset > LONG_MAX) {
296 fp->_flags |= __SERR;
297 errno = EOVERFLOW;
298 return (-1);
299 }
300 /* success: clear EOF indicator and discard ungetc() data */
301 if (HASUB(fp))
302 FREEUB(fp);
303 fp->_p = fp->_bf._base;
304 fp->_r = 0;
305 /* fp->_w = 0; */ /* unnecessary (I think...) */
306 fp->_flags &= ~__SEOF;
307 return (0);
308}
| 98 return (ret);
99}
100
101/*
102 * Seek the given file to the given offset.
103 * `Whence' must be one of the three SEEK_* macros.
104 */
105int
106_fseeko(fp, offset, whence, ltest)
107 FILE *fp;
108 off_t offset;
109 int whence;
110 int ltest;
111{
112 register fpos_t (*seekfn) __P((void *, fpos_t, int));
113 fpos_t target, curoff;
114 size_t n;
115 struct stat st;
116 int havepos;
117
118 /*
119 * Have to be able to seek.
120 */
121 if ((seekfn = fp->_seek) == NULL) {
122 errno = ESPIPE; /* historic practice */
123 return (-1);
124 }
125
126 /*
127 * Change any SEEK_CUR to SEEK_SET, and check `whence' argument.
128 * After this, whence is either SEEK_SET or SEEK_END.
129 */
130 switch (whence) {
131
132 case SEEK_CUR:
133 /*
134 * In order to seek relative to the current stream offset,
135 * we have to first find the current stream offset via
136 * ftell (see ftell for details).
137 */
138 if (_ftello(fp, &curoff))
139 return (-1);
140 if (curoff < 0) {
141 /* Unspecified position because of ungetc() at 0 */
142 errno = ESPIPE;
143 return (-1);
144 }
145 if (offset > 0 && curoff > OFF_MAX - offset) {
146 errno = EOVERFLOW;
147 return (-1);
148 }
149 offset += curoff;
150 if (offset < 0) {
151 errno = EINVAL;
152 return (-1);
153 }
154 if (ltest && offset > LONG_MAX) {
155 errno = EOVERFLOW;
156 return (-1);
157 }
158 whence = SEEK_SET;
159 havepos = 1;
160 break;
161
162 case SEEK_SET:
163 if (offset < 0) {
164 errno = EINVAL;
165 return (-1);
166 }
167 case SEEK_END:
168 curoff = 0; /* XXX just to keep gcc quiet */
169 havepos = 0;
170 break;
171
172 default:
173 errno = EINVAL;
174 return (-1);
175 }
176
177 /*
178 * Can only optimise if:
179 * reading (and not reading-and-writing);
180 * not unbuffered; and
181 * this is a `regular' Unix file (and hence seekfn==__sseek).
182 * We must check __NBF first, because it is possible to have __NBF
183 * and __SOPT both set.
184 */
185 if (fp->_bf._base == NULL)
186 __smakebuf(fp);
187 if (fp->_flags & (__SWR | __SRW | __SNBF | __SNPT))
188 goto dumb;
189 if ((fp->_flags & __SOPT) == 0) {
190 if (seekfn != __sseek ||
191 fp->_file < 0 || _fstat(fp->_file, &st) ||
192 (st.st_mode & S_IFMT) != S_IFREG) {
193 fp->_flags |= __SNPT;
194 goto dumb;
195 }
196 fp->_blksize = st.st_blksize;
197 fp->_flags |= __SOPT;
198 }
199
200 /*
201 * We are reading; we can try to optimise.
202 * Figure out where we are going and where we are now.
203 */
204 if (whence == SEEK_SET)
205 target = offset;
206 else {
207 if (_fstat(fp->_file, &st))
208 goto dumb;
209 if (offset > 0 && st.st_size > OFF_MAX - offset) {
210 errno = EOVERFLOW;
211 return (-1);
212 }
213 target = st.st_size + offset;
214 if ((off_t)target < 0) {
215 errno = EINVAL;
216 return (-1);
217 }
218 if (ltest && (off_t)target > LONG_MAX) {
219 errno = EOVERFLOW;
220 return (-1);
221 }
222 }
223
224 if (!havepos && _ftello(fp, &curoff))
225 goto dumb;
226
227 /*
228 * (If the buffer was modified, we have to
229 * skip this; see fgetln.c.)
230 */
231 if (fp->_flags & __SMOD)
232 goto abspos;
233
234 /*
235 * Compute the number of bytes in the input buffer (pretending
236 * that any ungetc() input has been discarded). Adjust current
237 * offset backwards by this count so that it represents the
238 * file offset for the first byte in the current input buffer.
239 */
240 if (HASUB(fp)) {
241 curoff += fp->_r; /* kill off ungetc */
242 n = fp->_extra->_up - fp->_bf._base;
243 curoff -= n;
244 n += fp->_ur;
245 } else {
246 n = fp->_p - fp->_bf._base;
247 curoff -= n;
248 n += fp->_r;
249 }
250
251 /*
252 * If the target offset is within the current buffer,
253 * simply adjust the pointers, clear EOF, undo ungetc(),
254 * and return.
255 */
256 if (target >= curoff && target < curoff + n) {
257 size_t o = target - curoff;
258
259 fp->_p = fp->_bf._base + o;
260 fp->_r = n - o;
261 if (HASUB(fp))
262 FREEUB(fp);
263 fp->_flags &= ~__SEOF;
264 return (0);
265 }
266
267abspos:
268 /*
269 * The place we want to get to is not within the current buffer,
270 * but we can still be kind to the kernel copyout mechanism.
271 * By aligning the file offset to a block boundary, we can let
272 * the kernel use the VM hardware to map pages instead of
273 * copying bytes laboriously. Using a block boundary also
274 * ensures that we only read one block, rather than two.
275 */
276 curoff = target & ~(fp->_blksize - 1);
277 if ((*seekfn)(fp->_cookie, curoff, SEEK_SET) == POS_ERR)
278 goto dumb;
279 fp->_r = 0;
280 fp->_p = fp->_bf._base;
281 if (HASUB(fp))
282 FREEUB(fp);
283 n = target - curoff;
284 if (n) {
285 if (__srefill(fp) || fp->_r < n)
286 goto dumb;
287 fp->_p += n;
288 fp->_r -= n;
289 }
290 fp->_flags &= ~__SEOF;
291 return (0);
292
293 /*
294 * We get here if we cannot optimise the seek ... just
295 * do it. Allow the seek function to change fp->_bf._base.
296 */
297dumb:
298 if (__sflush(fp) ||
299 (*seekfn)(fp->_cookie, (fpos_t)offset, whence) == POS_ERR)
300 return (-1);
301 if (ltest && fp->_offset > LONG_MAX) {
302 fp->_flags |= __SERR;
303 errno = EOVERFLOW;
304 return (-1);
305 }
306 /* success: clear EOF indicator and discard ungetc() data */
307 if (HASUB(fp))
308 FREEUB(fp);
309 fp->_p = fp->_bf._base;
310 fp->_r = 0;
311 /* fp->_w = 0; */ /* unnecessary (I think...) */
312 fp->_flags &= ~__SEOF;
313 return (0);
314}
|