getdelim.c revision 197752 
1/*-
2 * Copyright (c) 2009 David Schultz <das@FreeBSD.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27#include <sys/cdefs.h>
28__FBSDID("$FreeBSD: head/lib/libc/stdio/getdelim.c 197752 2009-10-04 19:43:36Z das $");
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(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 (__sferror(fp) || expandtofit(linep, 1, linecapp))
129			goto error;
130		FUNLOCKFILE(fp);
131		(*linep)[0] = '\0';
132		return (-1);
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		if (__srefill(fp)) {
140			if (__sferror(fp))
141				goto error;
142			goto done;	/* hit EOF */
143		}
144	}
145	endp++;	/* snarf the delimiter, too */
146	if (sappend(linep, &linelen, linecapp, fp->_p, endp - fp->_p))
147		goto error;
148	fp->_r -= endp - fp->_p;
149	fp->_p = endp;
150done:
151	/* Invariant: *linep has space for at least linelen+1 bytes. */
152	(*linep)[linelen] = '\0';
153	FUNLOCKFILE(fp);
154	return (linelen);
155
156error:
157	fp->_flags |= __SERR;
158	FUNLOCKFILE(fp);
159	return (-1);
160}
161