lib/libc/stdio/getdelim.c

   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  * $FreeBSD: src/lib/libc/stdio/getdelim.c,v 1.2 2009/04/06 13:50:04 das Exp $
  27  */
  28
  29 #include "namespace.h"
  30 #include <sys/param.h>
  31 #include <errno.h>
  32 #include <limits.h>
  33 #include <stdio.h>
  34 #include <stdlib.h>
  35 #include <string.h>
  36 #include "un-namespace.h"
  37
  38 #include "libc_private.h"
  39 #include "local.h"
  40 #include "priv_stdio.h"
  41
  42 static inline size_t
  43 p2roundup(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  */
  64 static inline int
  65 expandtofit(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  */
  95 static int
  96 sappend(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
 108 ssize_t
 109 getdelim(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 (*linecapp == 0)
 124                 *linep = NULL;
 125
 126         if (fp->pub._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->pub._p, delim, fp->pub._r)) == NULL) {
 137                 if (sappend(linep, &linelen, linecapp, fp->pub._p, fp->pub._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->pub._p, endp - fp->pub._p))
 147                 goto error;
 148         fp->pub._r -= endp - fp->pub._p;
 149         fp->pub._p = endp;
 150 done:
 151         /* Invariant: *linep has space for at least linelen+1 bytes. */
 152         (*linep)[linelen] = '\0';
 153         FUNLOCKFILE(fp);
 154         return (linelen);
 155
 156 error:
 157         fp->pub._flags |= __SERR;
 158         FUNLOCKFILE(fp);
 159         return (-1);
 160 }