1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2009 David Schultz <das@FreeBSD.org>
5 * Copyright (c) 2021 Dell EMC
6 * All rights reserved.
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 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30#include "namespace.h"
31#include <sys/param.h>
32#include <errno.h>
33#include <limits.h>
34#include <stdio.h>
35#include <stdlib.h>
36#include <string.h>
37#include "un-namespace.h"
38
39#include "libc_private.h"
40#include "local.h"
41
42static inline size_t
43p2roundup(size_t n)
44{
45
46	if (!powerof2(n)) {
47		n--;
48		n |= n >> 1;
49		n |= n >> 2;
50		n |= n >> 4;
51		n |= n >> 8;
52		n |= n >> 16;
53#if SIZE_T_MAX > 0xffffffffU
54		n |= n >> 32;
55#endif
56		n++;
57	}
58	return (n);
59}
60
61/*
62 * Expand *linep to hold len bytes (up to SSIZE_MAX + 1).
63 */
64static inline int
65expandtofit(char ** __restrict linep, size_t len, size_t * __restrict capp)
66{
67	char *newline;
68	size_t newcap;
69
70	if (len > (size_t)SSIZE_MAX + 1) {
71		errno = EOVERFLOW;
72		return (-1);
73	}
74	if (len > *capp) {
75		if (len == (size_t)SSIZE_MAX + 1)	/* avoid overflow */
76			newcap = (size_t)SSIZE_MAX + 1;
77		else
78			newcap = p2roundup(len);
79		newline = realloc(*linep, newcap);
80		if (newline == NULL)
81			return (-1);
82		*capp = newcap;
83		*linep = newline;
84	}
85	return (0);
86}
87
88/*
89 * Append the src buffer to the *dstp buffer. The buffers are of
90 * length srclen and *dstlenp, respectively, and dst has space for
91 * *dstlenp bytes. After the call, *dstlenp and *dstcapp are updated
92 * appropriately, and *dstp is reallocated if needed. Returns 0 on
93 * success, -1 on allocation failure.
94 */
95static int
96sappend(char ** __restrict dstp, size_t * __restrict dstlenp,
97	size_t * __restrict dstcapp, char * __restrict src, size_t srclen)
98{
99
100	/* ensure room for srclen + dstlen + terminating NUL */
101	if (expandtofit(dstp, srclen + *dstlenp + 1, dstcapp))
102		return (-1);
103	memcpy(*dstp + *dstlenp, src, srclen);
104	*dstlenp += srclen;
105	return (0);
106}
107
108ssize_t
109getdelim(char ** __restrict linep, size_t * __restrict linecapp, int delim,
110	 FILE * __restrict fp)
111{
112	u_char *endp;
113	size_t linelen;
114
115	FLOCKFILE_CANCELSAFE(fp);
116	ORIENT(fp, -1);
117
118	if (linep == NULL || linecapp == NULL) {
119		errno = EINVAL;
120		goto error;
121	}
122
123	if (*linep == NULL)
124		*linecapp = 0;
125
126	if (fp->_r <= 0 && __srefill(fp)) {
127		/* If fp is at EOF already, we just need space for the NUL. */
128		if (!__sfeof(fp) || expandtofit(linep, 1, linecapp))
129			goto error;
130		(*linep)[0] = '\0';
131		linelen = -1;
132		goto end;
133	}
134
135	linelen = 0;
136	while ((endp = memchr(fp->_p, delim, fp->_r)) == NULL) {
137		if (sappend(linep, &linelen, linecapp, fp->_p, fp->_r))
138			goto error;
139		errno = 0;
140		if (__srefill(fp)) {
141			if (__sfeof(fp))
142				goto done;
143			if (errno == EAGAIN) {
144				/*
145				 * We need to undo a partial read that has
146				 * been placed into linep or we would otherwise
147				 * lose it on the next read.
148				 */
149				while (linelen > 0) {
150					if (__ungetc((*linep)[--linelen],
151					    fp) == EOF)
152						goto error;
153				}
154				/*
155				 * This is not strictly needed but it is
156				 * possible a consumer has worked around an
157				 * older EAGAIN bug by buffering a partial
158				 * return.
159				 */
160				(*linep)[0] = '\0';
161			}
162			goto error;
163		}
164	}
165	endp++;	/* snarf the delimiter, too */
166	if (sappend(linep, &linelen, linecapp, fp->_p, endp - fp->_p))
167		goto error;
168	fp->_r -= endp - fp->_p;
169	fp->_p = endp;
170done:
171	/* Invariant: *linep has space for at least linelen+1 bytes. */
172	(*linep)[linelen] = '\0';
173end:
174	FUNLOCKFILE_CANCELSAFE();
175	return (linelen);
176
177error:
178	fp->_flags |= __SERR;
179	linelen = -1;
180	goto end;
181}
182