xref: /freebsd/lib/libc/stdio/getdelim.c (revision 0dbdecfd4f23486da21345fe446a28a1c27db3f2)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2009 David Schultz <das@FreeBSD.org>
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31 
32 #include "namespace.h"
33 #include <sys/param.h>
34 #include <errno.h>
35 #include <limits.h>
36 #include <stdio.h>
37 #include <stdlib.h>
38 #include <string.h>
39 #include "un-namespace.h"
40 
41 #include "libc_private.h"
42 #include "local.h"
43 
44 static inline size_t
45 p2roundup(size_t n)
46 {
47 
48 	if (!powerof2(n)) {
49 		n--;
50 		n |= n >> 1;
51 		n |= n >> 2;
52 		n |= n >> 4;
53 		n |= n >> 8;
54 		n |= n >> 16;
55 #if SIZE_T_MAX > 0xffffffffU
56 		n |= n >> 32;
57 #endif
58 		n++;
59 	}
60 	return (n);
61 }
62 
63 /*
64  * Expand *linep to hold len bytes (up to SSIZE_MAX + 1).
65  */
66 static inline int
67 expandtofit(char ** __restrict linep, size_t len, size_t * __restrict capp)
68 {
69 	char *newline;
70 	size_t newcap;
71 
72 	if (len > (size_t)SSIZE_MAX + 1) {
73 		errno = EOVERFLOW;
74 		return (-1);
75 	}
76 	if (len > *capp) {
77 		if (len == (size_t)SSIZE_MAX + 1)	/* avoid overflow */
78 			newcap = (size_t)SSIZE_MAX + 1;
79 		else
80 			newcap = p2roundup(len);
81 		newline = realloc(*linep, newcap);
82 		if (newline == NULL)
83 			return (-1);
84 		*capp = newcap;
85 		*linep = newline;
86 	}
87 	return (0);
88 }
89 
90 /*
91  * Append the src buffer to the *dstp buffer. The buffers are of
92  * length srclen and *dstlenp, respectively, and dst has space for
93  * *dstlenp bytes. After the call, *dstlenp and *dstcapp are updated
94  * appropriately, and *dstp is reallocated if needed. Returns 0 on
95  * success, -1 on allocation failure.
96  */
97 static int
98 sappend(char ** __restrict dstp, size_t * __restrict dstlenp,
99 	size_t * __restrict dstcapp, char * __restrict src, size_t srclen)
100 {
101 
102 	/* ensure room for srclen + dstlen + terminating NUL */
103 	if (expandtofit(dstp, srclen + *dstlenp + 1, dstcapp))
104 		return (-1);
105 	memcpy(*dstp + *dstlenp, src, srclen);
106 	*dstlenp += srclen;
107 	return (0);
108 }
109 
110 ssize_t
111 getdelim(char ** __restrict linep, size_t * __restrict linecapp, int delim,
112 	 FILE * __restrict fp)
113 {
114 	u_char *endp;
115 	size_t linelen;
116 
117 	FLOCKFILE_CANCELSAFE(fp);
118 	ORIENT(fp, -1);
119 
120 	if (linep == NULL || linecapp == NULL) {
121 		errno = EINVAL;
122 		goto error;
123 	}
124 
125 	if (*linep == NULL)
126 		*linecapp = 0;
127 
128 	if (fp->_r <= 0 && __srefill(fp)) {
129 		/* If fp is at EOF already, we just need space for the NUL. */
130 		if (!__sfeof(fp) || expandtofit(linep, 1, linecapp))
131 			goto error;
132 		(*linep)[0] = '\0';
133 		linelen = -1;
134 		goto end;
135 	}
136 
137 	linelen = 0;
138 	while ((endp = memchr(fp->_p, delim, fp->_r)) == NULL) {
139 		if (sappend(linep, &linelen, linecapp, fp->_p, fp->_r))
140 			goto error;
141 		if (__srefill(fp)) {
142 			if (!__sfeof(fp))
143 				goto error;
144 			goto done;	/* hit EOF */
145 		}
146 	}
147 	endp++;	/* snarf the delimiter, too */
148 	if (sappend(linep, &linelen, linecapp, fp->_p, endp - fp->_p))
149 		goto error;
150 	fp->_r -= endp - fp->_p;
151 	fp->_p = endp;
152 done:
153 	/* Invariant: *linep has space for at least linelen+1 bytes. */
154 	(*linep)[linelen] = '\0';
155 end:
156 	FUNLOCKFILE_CANCELSAFE();
157 	return (linelen);
158 
159 error:
160 	fp->_flags |= __SERR;
161 	linelen = -1;
162 	goto end;
163 }
164