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. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 * 32 * @(#)fvwrite.c 8.1 (Berkeley) 6/4/93 33 * $FreeBSD: head/lib/libc/stdio/fvwrite.c 249810 2013-04-23 14:36:44Z emaste $ 34 */ 35 36 #include <stdio.h> 37 #include <stdlib.h> 38 #include <string.h> 39 #include "local.h" 40 41 /* 42 * Write some memory regions. Return zero on success, EOF on error. 43 * 44 * This routine is large and unsightly, but most of the ugliness due 45 * to the three different kinds of output buffering is handled here. 46 */ 47 int 48 __sfvwrite(FILE *fp, struct __suio *uio) 49 { 50 size_t len; 51 char *p; 52 struct __siov *iov; 53 int w, s; 54 char *nl; 55 int nlknown, nldist; 56 57 if (uio->uio_resid == 0) 58 return (0); 59 /* make sure we can write */ 60 if (prepwrite(fp) != 0) 61 return (EOF); 62 63 #define MIN(a, b) ((a) < (b) ? (a) : (b)) 64 #define COPY(n) (void)memcpy((void *)fp->pub._p, (void *)p, (size_t)(n)) 65 66 iov = uio->uio_iov; 67 p = iov->iov_base; 68 len = iov->iov_len; 69 iov++; 70 #define GETIOV(extra_work) \ 71 while (len == 0) { \ 72 extra_work; \ 73 p = iov->iov_base; \ 74 len = iov->iov_len; \ 75 iov++; \ 76 } 77 if (fp->pub._flags & __SNBF) { 78 /* 79 * Unbuffered: write up to BUFSIZ bytes at a time. 80 */ 81 do { 82 GETIOV(;); 83 w = _swrite(fp, p, MIN(len, BUFSIZ)); 84 if (w <= 0) 85 goto err; 86 p += w; 87 len -= w; 88 } while ((uio->uio_resid -= w) != 0); 89 } else if ((fp->pub._flags & __SLBF) == 0) { 90 /* 91 * Fully buffered: fill partially full buffer, if any, 92 * and then flush. If there is no partial buffer, write 93 * one _bf._size byte chunk directly (without copying). 94 * 95 * String output is a special case: write as many bytes 96 * as fit, but pretend we wrote everything. This makes 97 * snprintf() return the number of bytes needed, rather 98 * than the number used, and avoids its write function 99 * (so that the write function can be invalid). 100 */ 101 do { 102 GETIOV(;); 103 if ((fp->pub._flags & (__SALC | __SSTR)) == 104 (__SALC | __SSTR) && fp->pub._w < len) { 105 size_t blen = fp->pub._p - fp->_bf._base; 106 107 /* 108 * Alloc an extra 128 bytes (+ 1 for NULL) 109 * so we don't call realloc(3) so often. 110 */ 111 fp->pub._w = len + 128; 112 fp->_bf._size = blen + len + 128; 113 fp->_bf._base = 114 reallocf(fp->_bf._base, fp->_bf._size + 1); 115 if (fp->_bf._base == NULL) 116 goto err; 117 fp->pub._p = fp->_bf._base + blen; 118 } 119 w = fp->pub._w; 120 if (fp->pub._flags & __SSTR) { 121 if (len < w) 122 w = len; 123 if (w > 0) { 124 COPY(w); /* copy MIN(fp->pub._w,len), */ 125 fp->pub._w -= w; 126 fp->pub._p += w; 127 } 128 w = len; /* but pretend copied all */ 129 } else if (fp->pub._p > fp->_bf._base && len > w) { 130 /* fill and flush */ 131 COPY(w); 132 /* fp->pub._w -= w; */ /* unneeded */ 133 fp->pub._p += w; 134 if (__fflush(fp)) 135 goto err; 136 } else if (len >= (w = fp->_bf._size)) { 137 /* write directly */ 138 w = _swrite(fp, p, w); 139 if (w <= 0) 140 goto err; 141 } else { 142 /* fill and done */ 143 w = len; 144 COPY(w); 145 fp->pub._w -= w; 146 fp->pub._p += w; 147 } 148 p += w; 149 len -= w; 150 } while ((uio->uio_resid -= w) != 0); 151 } else { 152 /* 153 * Line buffered: like fully buffered, but we 154 * must check for newlines. Compute the distance 155 * to the first newline (including the newline), 156 * or `infinity' if there is none, then pretend 157 * that the amount to write is MIN(len,nldist). 158 */ 159 nlknown = 0; 160 nldist = 0; /* XXX just to keep gcc happy */ 161 do { 162 GETIOV(nlknown = 0); 163 if (!nlknown) { 164 nl = memchr((void *)p, '\n', len); 165 nldist = nl ? nl + 1 - p : len + 1; 166 nlknown = 1; 167 } 168 s = MIN(len, nldist); 169 w = fp->pub._w + fp->_bf._size; 170 if (fp->pub._p > fp->_bf._base && s > w) { 171 COPY(w); 172 /* fp->pub._w -= w; */ 173 fp->pub._p += w; 174 if (__fflush(fp)) 175 goto err; 176 } else if (s >= (w = fp->_bf._size)) { 177 w = _swrite(fp, p, w); 178 if (w <= 0) 179 goto err; 180 } else { 181 w = s; 182 COPY(w); 183 fp->pub._w -= w; 184 fp->pub._p += w; 185 } 186 if ((nldist -= w) == 0) { 187 /* copied the newline: flush and forget */ 188 if (__fflush(fp)) 189 goto err; 190 nlknown = 0; 191 } 192 p += w; 193 len -= w; 194 } while ((uio->uio_resid -= w) != 0); 195 } 196 return (0); 197 198 err: 199 fp->pub._flags |= __SERR; 200 return (EOF); 201 } 202