1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1990, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * Chris Torek.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35 #include "namespace.h"
36 #include <errno.h>
37 #include <limits.h>
38 #include <stdio.h>
39 #include <stdlib.h>
40 #include <string.h>
41 #include "un-namespace.h"
42 #include "libc_private.h"
43 #include "local.h"
44
45 /*
46 * Expand the line buffer. Return -1 on error.
47 */
48 int
__slbexpand(FILE * fp,size_t newsize)49 __slbexpand(FILE *fp, size_t newsize)
50 {
51 void *p;
52
53 if (fp->_lb._size >= newsize)
54 return (0);
55 if (newsize > INT_MAX) {
56 errno = ENOMEM;
57 return (-1);
58 }
59 if ((p = realloc(fp->_lb._base, newsize)) == NULL)
60 return (-1);
61 fp->_lb._base = p;
62 fp->_lb._size = newsize;
63 return (0);
64 }
65
66 /*
67 * Get an input line. The returned pointer often (but not always)
68 * points into a stdio buffer. Fgetln does not alter the text of
69 * the returned line (which is thus not a C string because it will
70 * not necessarily end with '\0'), but does allow callers to modify
71 * it if they wish. Thus, we set __SMOD in case the caller does.
72 */
73 char *
fgetln(FILE * fp,size_t * lenp)74 fgetln(FILE *fp, size_t *lenp)
75 {
76 unsigned char *p;
77 char *ret;
78 size_t len;
79 size_t off;
80
81 FLOCKFILE_CANCELSAFE(fp);
82 ORIENT(fp, -1);
83 /* make sure there is input */
84 if (fp->_r <= 0 && __srefill(fp)) {
85 *lenp = 0;
86 ret = NULL;
87 goto end;
88 }
89
90 /* look for a newline in the input */
91 if ((p = memchr((void *)fp->_p, '\n', (size_t)fp->_r)) != NULL) {
92 /*
93 * Found one. Flag buffer as modified to keep fseek from
94 * `optimising' a backward seek, in case the user stomps on
95 * the text.
96 */
97 p++; /* advance over it */
98 ret = (char *)fp->_p;
99 *lenp = len = p - fp->_p;
100 fp->_flags |= __SMOD;
101 fp->_r -= len;
102 fp->_p = p;
103 goto end;
104 }
105
106 /*
107 * We have to copy the current buffered data to the line buffer.
108 * As a bonus, though, we can leave off the __SMOD.
109 *
110 * OPTIMISTIC is length that we (optimistically) expect will
111 * accommodate the `rest' of the string, on each trip through the
112 * loop below.
113 */
114 #define OPTIMISTIC 80
115
116 for (len = fp->_r, off = 0;; len += fp->_r) {
117 size_t diff;
118
119 /*
120 * Make sure there is room for more bytes. Copy data from
121 * file buffer to line buffer, refill file and look for
122 * newline. The loop stops only when we find a newline.
123 */
124 if (__slbexpand(fp, len + OPTIMISTIC))
125 goto error;
126 (void)memcpy((void *)(fp->_lb._base + off), (void *)fp->_p,
127 len - off);
128 off = len;
129 if (__srefill(fp)) {
130 if (__sfeof(fp))
131 break;
132 goto error;
133 }
134 if ((p = memchr((void *)fp->_p, '\n', (size_t)fp->_r)) == NULL)
135 continue;
136
137 /* got it: finish up the line (like code above) */
138 p++;
139 diff = p - fp->_p;
140 len += diff;
141 if (__slbexpand(fp, len))
142 goto error;
143 (void)memcpy((void *)(fp->_lb._base + off), (void *)fp->_p,
144 diff);
145 fp->_r -= diff;
146 fp->_p = p;
147 break;
148 }
149 *lenp = len;
150 ret = (char *)fp->_lb._base;
151 end:
152 FUNLOCKFILE_CANCELSAFE();
153 return (ret);
154
155 error:
156 *lenp = 0; /* ??? */
157 fp->_flags |= __SERR;
158 ret = NULL;
159 goto end;
160 }
161