lib/libc/stdio/getdelim.c

   1 /* $NetBSD: getdelim.c,v 1.11 2009/12/02 11:14:47 roy 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 1.11 2009/12/02 11:14:47 roy 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
  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                 return -1;
  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
 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 }