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)
34 static char sccsid[] = "@(#)fgetln.c 8.2 (Berkeley) 1/2/94";
35 #endif /* LIBC_SCCS and not lint */
36 #include <sys/cdefs.h>
37 __FBSDID("$FreeBSD$");
38
39 #include "namespace.h"
40 #include <errno.h>
41 #include <limits.h>
42 #include <stdio.h>
43 #include <stdlib.h>
44 #include <string.h>
45 #include "un-namespace.h"
46 #include "libc_private.h"
47 #include "local.h"
48
49 /*
50 * Expand the line buffer. Return -1 on error.
51 #ifdef notdef
52 * The `new size' does not account for a terminating '\0',
53 * so we add 1 here.
54 #endif
55 */
56 int
__slbexpand(FILE * fp,size_t newsize)57 __slbexpand(FILE *fp, size_t newsize)
58 {
59 void *p;
60
61 #ifdef notdef
62 ++newsize;
63 #endif
64 if (fp->_lb._size >= newsize)
65 return (0);
66 if (newsize > INT_MAX) {
67 errno = ENOMEM;
68 return (-1);
69 }
70 if ((p = realloc(fp->_lb._base, newsize)) == NULL)
71 return (-1);
72 fp->_lb._base = p;
73 fp->_lb._size = newsize;
74 return (0);
75 }
76
77 /*
78 * Get an input line. The returned pointer often (but not always)
79 * points into a stdio buffer. Fgetln does not alter the text of
80 * the returned line (which is thus not a C string because it will
81 * not necessarily end with '\0'), but does allow callers to modify
82 * it if they wish. Thus, we set __SMOD in case the caller does.
83 */
84 char *
fgetln(FILE * fp,size_t * lenp)85 fgetln(FILE *fp, size_t *lenp)
86 {
87 unsigned char *p;
88 char *ret;
89 size_t len;
90 size_t off;
91
92 FLOCKFILE_CANCELSAFE(fp);
93 ORIENT(fp, -1);
94 /* make sure there is input */
95 if (fp->_r <= 0 && __srefill(fp)) {
96 *lenp = 0;
97 ret = NULL;
98 goto end;
99 }
100
101 /* look for a newline in the input */
102 if ((p = memchr((void *)fp->_p, '\n', (size_t)fp->_r)) != NULL) {
103 /*
104 * Found one. Flag buffer as modified to keep fseek from
105 * `optimising' a backward seek, in case the user stomps on
106 * the text.
107 */
108 p++; /* advance over it */
109 ret = (char *)fp->_p;
110 *lenp = len = p - fp->_p;
111 fp->_flags |= __SMOD;
112 fp->_r -= len;
113 fp->_p = p;
114 goto end;
115 }
116
117 /*
118 * We have to copy the current buffered data to the line buffer.
119 * As a bonus, though, we can leave off the __SMOD.
120 *
121 * OPTIMISTIC is length that we (optimistically) expect will
122 * accommodate the `rest' of the string, on each trip through the
123 * loop below.
124 */
125 #define OPTIMISTIC 80
126
127 for (len = fp->_r, off = 0;; len += fp->_r) {
128 size_t diff;
129
130 /*
131 * Make sure there is room for more bytes. Copy data from
132 * file buffer to line buffer, refill file and look for
133 * newline. The loop stops only when we find a newline.
134 */
135 if (__slbexpand(fp, len + OPTIMISTIC))
136 goto error;
137 (void)memcpy((void *)(fp->_lb._base + off), (void *)fp->_p,
138 len - off);
139 off = len;
140 if (__srefill(fp)) {
141 if (__sfeof(fp))
142 break;
143 goto error;
144 }
145 if ((p = memchr((void *)fp->_p, '\n', (size_t)fp->_r)) == NULL)
146 continue;
147
148 /* got it: finish up the line (like code above) */
149 p++;
150 diff = p - fp->_p;
151 len += diff;
152 if (__slbexpand(fp, len))
153 goto error;
154 (void)memcpy((void *)(fp->_lb._base + off), (void *)fp->_p,
155 diff);
156 fp->_r -= diff;
157 fp->_p = p;
158 break;
159 }
160 *lenp = len;
161 #ifdef notdef
162 fp->_lb._base[len] = '\0';
163 #endif
164 ret = (char *)fp->_lb._base;
165 end:
166 FUNLOCKFILE_CANCELSAFE();
167 return (ret);
168
169 error:
170 *lenp = 0; /* ??? */
171 fp->_flags |= __SERR;
172 ret = NULL;
173 goto end;
174 }
175