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 * 4. 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[] = "@(#)fseek.c 8.3 (Berkeley) 1/2/94";
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 * 4. 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[] = "@(#)fseek.c 8.3 (Berkeley) 1/2/94";
35#endif /* LIBC_SCCS and not lint */
36#include <sys/cdefs.h>
|
37__FBSDID("$FreeBSD: head/lib/libc/stdio/fseek.c 165903 2007-01-09 00:28:16Z imp $");
| 37__FBSDID("$FreeBSD: head/lib/libc/stdio/fseek.c 170907 2007-06-18 02:09:08Z ache $");
|
38
39#include "namespace.h"
40#include <sys/types.h>
41#include <sys/stat.h>
42#include <errno.h>
43#include <fcntl.h>
44#include <limits.h>
45#include <stdio.h>
46#include <stdlib.h>
47#include "un-namespace.h"
48#include "local.h"
49#include "libc_private.h"
50
51#define POS_ERR (-(fpos_t)1)
52
53int
54fseek(fp, offset, whence)
55 FILE *fp;
56 long offset;
57 int whence;
58{
59 int ret;
60 int serrno = errno;
61
62 /* make sure stdio is set up */
63 if (!__sdidinit)
64 __sinit();
65
66 FLOCKFILE(fp);
67 ret = _fseeko(fp, (off_t)offset, whence, 1);
68 FUNLOCKFILE(fp);
69 if (ret == 0)
70 errno = serrno;
71 return (ret);
72}
73
74int
75fseeko(fp, offset, whence)
76 FILE *fp;
77 off_t offset;
78 int whence;
79{
80 int ret;
81 int serrno = errno;
82
83 /* make sure stdio is set up */
84 if (!__sdidinit)
85 __sinit();
86
87 FLOCKFILE(fp);
88 ret = _fseeko(fp, offset, whence, 0);
89 FUNLOCKFILE(fp);
90 if (ret == 0)
91 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 fpos_t (*seekfn)(void *, fpos_t, int);
107 fpos_t target, curoff, ret;
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 memset(&fp->_extra->mbstate, 0, sizeof(mbstate_t));
259 return (0);
260 }
261
262abspos:
263 /*
264 * The place we want to get to is not within the current buffer,
265 * but we can still be kind to the kernel copyout mechanism.
266 * By aligning the file offset to a block boundary, we can let
267 * the kernel use the VM hardware to map pages instead of
268 * copying bytes laboriously. Using a block boundary also
269 * ensures that we only read one block, rather than two.
270 */
271 curoff = target & ~(fp->_blksize - 1);
272 if (_sseek(fp, curoff, SEEK_SET) == POS_ERR)
273 goto dumb;
274 fp->_r = 0;
275 fp->_p = fp->_bf._base;
276 if (HASUB(fp))
277 FREEUB(fp);
278 n = target - curoff;
279 if (n) {
280 if (__srefill(fp) || fp->_r < n)
281 goto dumb;
282 fp->_p += n;
283 fp->_r -= n;
284 }
285 fp->_flags &= ~__SEOF;
| 38
39#include "namespace.h"
40#include <sys/types.h>
41#include <sys/stat.h>
42#include <errno.h>
43#include <fcntl.h>
44#include <limits.h>
45#include <stdio.h>
46#include <stdlib.h>
47#include "un-namespace.h"
48#include "local.h"
49#include "libc_private.h"
50
51#define POS_ERR (-(fpos_t)1)
52
53int
54fseek(fp, offset, whence)
55 FILE *fp;
56 long offset;
57 int whence;
58{
59 int ret;
60 int serrno = errno;
61
62 /* make sure stdio is set up */
63 if (!__sdidinit)
64 __sinit();
65
66 FLOCKFILE(fp);
67 ret = _fseeko(fp, (off_t)offset, whence, 1);
68 FUNLOCKFILE(fp);
69 if (ret == 0)
70 errno = serrno;
71 return (ret);
72}
73
74int
75fseeko(fp, offset, whence)
76 FILE *fp;
77 off_t offset;
78 int whence;
79{
80 int ret;
81 int serrno = errno;
82
83 /* make sure stdio is set up */
84 if (!__sdidinit)
85 __sinit();
86
87 FLOCKFILE(fp);
88 ret = _fseeko(fp, offset, whence, 0);
89 FUNLOCKFILE(fp);
90 if (ret == 0)
91 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 fpos_t (*seekfn)(void *, fpos_t, int);
107 fpos_t target, curoff, ret;
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 memset(&fp->_extra->mbstate, 0, sizeof(mbstate_t));
259 return (0);
260 }
261
262abspos:
263 /*
264 * The place we want to get to is not within the current buffer,
265 * but we can still be kind to the kernel copyout mechanism.
266 * By aligning the file offset to a block boundary, we can let
267 * the kernel use the VM hardware to map pages instead of
268 * copying bytes laboriously. Using a block boundary also
269 * ensures that we only read one block, rather than two.
270 */
271 curoff = target & ~(fp->_blksize - 1);
272 if (_sseek(fp, curoff, SEEK_SET) == POS_ERR)
273 goto dumb;
274 fp->_r = 0;
275 fp->_p = fp->_bf._base;
276 if (HASUB(fp))
277 FREEUB(fp);
278 n = target - curoff;
279 if (n) {
280 if (__srefill(fp) || fp->_r < n)
281 goto dumb;
282 fp->_p += n;
283 fp->_r -= n;
284 }
285 fp->_flags &= ~__SEOF;
|
| 286 memset(&fp->_extra->mbstate, 0, sizeof(mbstate_t));
|
286 return (0);
287
288 /*
289 * We get here if we cannot optimise the seek ... just
290 * do it. Allow the seek function to change fp->_bf._base.
291 */
292dumb:
293 if (__sflush(fp) ||
294 (ret = _sseek(fp, (fpos_t)offset, whence)) == POS_ERR)
295 return (-1);
| 287 return (0);
288
289 /*
290 * We get here if we cannot optimise the seek ... just
291 * do it. Allow the seek function to change fp->_bf._base.
292 */
293dumb:
294 if (__sflush(fp) ||
295 (ret = _sseek(fp, (fpos_t)offset, whence)) == POS_ERR)
296 return (-1);
|
| 297 if (ltest && ret > LONG_MAX) {
298 fp->_flags |= __SERR;
299 errno = EOVERFLOW;
300 return (-1);
301 }
|
296 /* success: clear EOF indicator and discard ungetc() data */
297 if (HASUB(fp))
298 FREEUB(fp);
299 fp->_p = fp->_bf._base;
300 fp->_r = 0;
301 /* fp->_w = 0; */ /* unnecessary (I think...) */
302 fp->_flags &= ~__SEOF;
303 memset(&fp->_extra->mbstate, 0, sizeof(mbstate_t));
| 302 /* success: clear EOF indicator and discard ungetc() data */
303 if (HASUB(fp))
304 FREEUB(fp);
305 fp->_p = fp->_bf._base;
306 fp->_r = 0;
307 /* fp->_w = 0; */ /* unnecessary (I think...) */
308 fp->_flags &= ~__SEOF;
309 memset(&fp->_extra->mbstate, 0, sizeof(mbstate_t));
|
304 if (ltest && ret > LONG_MAX) {
305 fp->_flags |= __SERR;
306 errno = EOVERFLOW;
307 return (-1);
308 }
| |
309 return (0);
310}
| 310 return (0);
311}
|