1 /* $NetBSD: getdelim.c,v 1.14 2017/06/08 15:59:45 uwe Exp $ */
2 
3 /*
4  * Copyright (c) 2009 The NetBSD Foundation, Inc.
5  *
6  * This code is derived from software contributed to The NetBSD Foundation
7  * by Roy Marples.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28  */
29 
30 #include <sys/cdefs.h>
31 __RCSID("$NetBSD: getdelim.c,v 1.14 2017/06/08 15:59:45 uwe Exp $");
32 
33 #include "namespace.h"
34 
35 #include <sys/param.h>
36 
37 #include <assert.h>
38 #include <errno.h>
39 #include <limits.h>
40 #include <stdio.h>
41 #include <stdlib.h>
42 #include <string.h>
43 
44 #include "reentrant.h"
45 #include "local.h"
46 
47 #ifdef __weak_alias
__weak_alias(getdelim,_getdelim)48 __weak_alias(getdelim, _getdelim)
49 #endif
50 
51 /* Minimum buffer size we create.
52  * This should allow config files to fit into our power of 2 buffer growth
53  * without the need for a realloc. */
54 #define MINBUF      128
55 
56 ssize_t
57 __getdelim(char **__restrict buf, size_t *__restrict buflen,
58     int sep, FILE *__restrict fp)
59 {
60           unsigned char *p;
61           size_t len, newlen, off;
62           char *newb;
63 
64           _DIAGASSERT(fp != NULL);
65 
66           if (buf == NULL || buflen == NULL) {
67                     errno = EINVAL;
68                     goto error;
69           }
70 
71           /* If buf is NULL, we have to assume a size of zero */
72           if (*buf == NULL)
73                     *buflen = 0;
74 
75           _SET_ORIENTATION(fp, -1);
76           off = 0;
77           do {
78                     /* If the input buffer is empty, refill it */
79                     if (fp->_r <= 0 && __srefill(fp)) {
80                               if (__sferror(fp))
81                                         goto error;
82                               /* No error, so EOF. */
83                               break;
84                     }
85 
86                     /* Scan through looking for the separator */
87                     p = memchr(fp->_p, sep, (size_t)fp->_r);
88                     if (p == NULL)
89                               len = fp->_r;
90                     else
91                               len = (p - fp->_p) + 1;
92 
93                     newlen = off + len;
94                     /* Ensure we can handle it */
95                     if (newlen < off || newlen > SSIZE_MAX) {
96                               errno = EOVERFLOW;
97                               goto error;
98                     }
99                     newlen++; /* reserve space for the null terminator */
100                     if (newlen > *buflen) {
101                               if (newlen < MINBUF)
102                                         newlen = MINBUF;
103                               if (!powerof2(newlen)) {
104                                         /* Grow the buffer to the next power of 2 */
105                                         newlen--;
106                                         newlen |= newlen >> 1;
107                                         newlen |= newlen >> 2;
108                                         newlen |= newlen >> 4;
109                                         newlen |= newlen >> 8;
110                                         newlen |= newlen >> 16;
111 #if SIZE_T_MAX > 0xffffffffU
112                                         newlen |= newlen >> 32;
113 #endif
114                                         newlen++;
115                               }
116 
117                               newb = realloc(*buf, newlen);
118                               if (newb == NULL)
119                                         goto error;
120                               *buf = newb;
121                               *buflen = newlen;
122                     }
123 
124                     (void)memcpy((*buf + off), fp->_p, len);
125                     /* Safe, len is never greater than what fp->_r can fit. */
126                     fp->_r -= (int)len;
127                     fp->_p += (int)len;
128                     off += len;
129           } while (p == NULL);
130 
131           /* POSIX demands we return -1 on EOF. */
132           if (off == 0)
133                     return -1;
134 
135           if (*buf != NULL)
136                     *(*buf + off) = '\0';
137           return off;
138 
139 error:
140           fp->_flags |= __SERR;
141           return -1;
142 }
143 
144 ssize_t
getdelim(char ** __restrict buf,size_t * __restrict buflen,int sep,FILE * __restrict fp)145 getdelim(char **__restrict buf, size_t *__restrict buflen,
146     int sep, FILE *__restrict fp)
147 {
148           ssize_t n;
149 
150           FLOCKFILE(fp);
151           n = __getdelim(buf, buflen, sep, fp);
152           FUNLOCKFILE(fp);
153           return n;
154 }
155