stdio/FreeBSD/fvwrite.c

   1 /*-
   2  * Copyright (c) 1990, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * This code is derived from software contributed to Berkeley by
   6  * Chris Torek.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *      This product includes software developed by the University of
  19  *      California, Berkeley and its contributors.
  20  * 4. Neither the name of the University nor the names of its contributors
  21  *    may be used to endorse or promote products derived from this software
  22  *    without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  */
  36
  37 #if defined(LIBC_SCCS) && !defined(lint)
  38 static char sccsid[] = "@(#)fvwrite.c   8.1 (Berkeley) 6/4/93";
  39 #endif /* LIBC_SCCS and not lint */
  40 #include <sys/cdefs.h>
  41 __FBSDID("$FreeBSD: src/lib/libc/stdio/fvwrite.c,v 1.16 2004/03/02 19:43:51 jkh Exp $");
  42
  43 #include <errno.h>
  44 #include <stdio.h>
  45 #include <stdlib.h>
  46 #include <string.h>
  47 #include "local.h"
  48 #include "fvwrite.h"
  49
  50 /*
  51  * Write some memory regions.  Return zero on success, EOF on error.
  52  *
  53  * This routine is large and unsightly, but most of the ugliness due
  54  * to the three different kinds of output buffering is handled here.
  55  */
  56 int
  57 __sfvwrite(fp, uio)
  58         FILE *fp;
  59         struct __suio *uio;
  60 {
  61         size_t len;
  62         char *p;
  63         struct __siov *iov;
  64         int w, s;
  65         char *nl;
  66         int nlknown, nldist;
  67
  68         if ((len = uio->uio_resid) == 0)
  69                 return (0);
  70         /* make sure we can write */
  71         if (cantwrite(fp)) {
  72                 errno = EBADF;
  73                 return (EOF);
  74         }
  75
  76 #define MIN(a, b) ((a) < (b) ? (a) : (b))
  77 #define COPY(n)   (void)memcpy((void *)fp->_p, (void *)p, (size_t)(n))
  78
  79         iov = uio->uio_iov;
  80         p = iov->iov_base;
  81         len = iov->iov_len;
  82         iov++;
  83 #define GETIOV(extra_work) \
  84         while (len == 0) { \
  85                 extra_work; \
  86                 p = iov->iov_base; \
  87                 len = iov->iov_len; \
  88                 iov++; \
  89         }
  90         if (fp->_flags & __SNBF) {
  91                 /*
  92                  * Unbuffered: write up to BUFSIZ bytes at a time.
  93                  */
  94                 do {
  95                         GETIOV(;);
  96                         w = _swrite(fp, p, MIN(len, BUFSIZ));
  97                         if (w <= 0)
  98                                 goto err;
  99                         p += w;
 100                         len -= w;
 101                 } while ((uio->uio_resid -= w) != 0);
 102         } else if ((fp->_flags & __SLBF) == 0) {
 103                 /*
 104                  * Fully buffered: fill partially full buffer, if any,
 105                  * and then flush.  If there is no partial buffer, write
 106                  * one _bf._size byte chunk directly (without copying).
 107                  *
 108                  * String output is a special case: write as many bytes
 109                  * as fit, but pretend we wrote everything.  This makes
 110                  * snprintf() return the number of bytes needed, rather
 111                  * than the number used, and avoids its write function
 112                  * (so that the write function can be invalid).
 113                  */
 114                 do {
 115                         GETIOV(;);
 116                         if ((fp->_flags & (__SALC | __SSTR)) ==
 117                             (__SALC | __SSTR) && fp->_w < len) {
 118                                 size_t blen = fp->_p - fp->_bf._base;
 119
 120                                 /*
 121                                  * Alloc an extra 128 bytes (+ 1 for NULL)
 122                                  * so we don't call realloc(3) so often.
 123                                  */
 124                                 fp->_w = len + 128;
 125                                 fp->_bf._size = blen + len + 128;
 126                                 fp->_bf._base =
 127                                     reallocf(fp->_bf._base, fp->_bf._size + 1);
 128                                 if (fp->_bf._base == NULL)
 129                                         goto err;
 130                                 fp->_p = fp->_bf._base + blen;
 131                         }
 132                         w = fp->_w;
 133                         if (fp->_flags & __SSTR) {
 134                                 if (len < w)
 135                                         w = len;
 136                                 if (w > 0) {
 137                                         COPY(w);        /* copy MIN(fp->_w,len), */
 138                                         fp->_w -= w;
 139                                         fp->_p += w;
 140                                 }
 141                                 w = len;        /* but pretend copied all */
 142                         } else if (fp->_p > fp->_bf._base && len > w) {
 143                                 /* fill and flush */
 144                                 COPY(w);
 145                                 /* fp->_w -= w; */ /* unneeded */
 146                                 fp->_p += w;
 147                                 if (__fflush(fp))
 148                                         goto err;
 149                         } else if (len >= (w = fp->_bf._size)) {
 150                                 /* write directly */
 151                                 w = _swrite(fp, p, w);
 152                                 if (w <= 0)
 153                                         goto err;
 154                         } else {
 155                                 /* fill and done */
 156                                 w = len;
 157                                 COPY(w);
 158                                 fp->_w -= w;
 159                                 fp->_p += w;
 160                         }
 161                         p += w;
 162                         len -= w;
 163                 } while ((uio->uio_resid -= w) != 0);
 164         } else {
 165                 /*
 166                  * Line buffered: like fully buffered, but we
 167                  * must check for newlines.  Compute the distance
 168                  * to the first newline (including the newline),
 169                  * or `infinity' if there is none, then pretend
 170                  * that the amount to write is MIN(len,nldist).
 171                  */
 172                 nlknown = 0;
 173                 nldist = 0;     /* XXX just to keep gcc happy */
 174                 do {
 175                         GETIOV(nlknown = 0);
 176                         if (!nlknown) {
 177                                 nl = memchr((void *)p, '\n', len);
 178                                 nldist = nl ? nl + 1 - p : len + 1;
 179                                 nlknown = 1;
 180                         }
 181                         s = MIN(len, nldist);
 182                         w = fp->_w + fp->_bf._size;
 183                         if (fp->_p > fp->_bf._base && s > w) {
 184                                 COPY(w);
 185                                 /* fp->_w -= w; */
 186                                 fp->_p += w;
 187                                 if (__fflush(fp))
 188                                         goto err;
 189                         } else if (s >= (w = fp->_bf._size)) {
 190                                 w = _swrite(fp, p, w);
 191                                 if (w <= 0)
 192                                         goto err;
 193                         } else {
 194                                 w = s;
 195                                 COPY(w);
 196                                 fp->_w -= w;
 197                                 fp->_p += w;
 198                         }
 199                         if ((nldist -= w) == 0) {
 200                                 /* copied the newline: flush and forget */
 201                                 if (__fflush(fp))
 202                                         goto err;
 203                                 nlknown = 0;
 204                         }
 205                         p += w;
 206                         len -= w;
 207                 } while ((uio->uio_resid -= w) != 0);
 208         }
 209         return (0);
 210
 211 err:
 212         fp->_flags |= __SERR;
 213         return (EOF);
 214 }