1 /* $OpenBSD: fvwrite.c,v 1.20 2017/03/17 16:06:33 millert Exp $ */ 2 /*- 3 * Copyright (c) 1990, 1993 4 * The Regents of the University of California. All rights reserved. 5 * 6 * This code is derived from software contributed to Berkeley by 7 * Chris Torek. 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 * 3. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 #include <stdio.h> 35 #include <stdlib.h> 36 #include <string.h> 37 #include <errno.h> 38 #include <unistd.h> 39 #include "local.h" 40 #include "fvwrite.h" 41 42 /* 43 * Write some memory regions. Return zero on success, EOF on error. 44 * 45 * This routine is large and unsightly, but most of the ugliness due 46 * to the three different kinds of output buffering is handled here. 47 */ 48 int 49 __sfvwrite(FILE *fp, struct __suio *uio) 50 { 51 size_t len; 52 char *p; 53 struct __siov *iov; 54 int w, s; 55 char *nl; 56 int nlknown, nldist; 57 58 if ((len = uio->uio_resid) == 0) 59 return (0); 60 /* make sure we can write */ 61 if (cantwrite(fp)) { 62 errno = EBADF; 63 return (EOF); 64 } 65 66 #define MIN(a, b) ((a) < (b) ? (a) : (b)) 67 #define COPY(n) (void)memcpy(fp->_p, p, n) 68 69 iov = uio->uio_iov; 70 p = iov->iov_base; 71 len = iov->iov_len; 72 iov++; 73 #define GETIOV(extra_work) \ 74 while (len == 0) { \ 75 extra_work; \ 76 p = iov->iov_base; \ 77 len = iov->iov_len; \ 78 iov++; \ 79 } 80 if (fp->_flags & __SNBF) { 81 /* 82 * Unbuffered: write up to BUFSIZ bytes at a time. 83 */ 84 do { 85 GETIOV(;); 86 w = (*fp->_write)(fp->_cookie, p, MIN(len, BUFSIZ)); 87 if (w <= 0) 88 goto err; 89 p += w; 90 len -= w; 91 } while ((uio->uio_resid -= w) != 0); 92 } else if ((fp->_flags & __SLBF) == 0) { 93 /* 94 * Fully buffered: fill partially full buffer, if any, 95 * and then flush. If there is no partial buffer, write 96 * one _bf._size byte chunk directly (without copying). 97 * 98 * String output is a special case: write as many bytes 99 * as fit, but pretend we wrote everything. This makes 100 * snprintf() return the number of bytes needed, rather 101 * than the number used, and avoids its write function 102 * (so that the write function can be invalid). 103 */ 104 do { 105 GETIOV(;); 106 if ((fp->_flags & (__SALC | __SSTR)) == 107 (__SALC | __SSTR) && fp->_w < len) { 108 size_t blen = fp->_p - fp->_bf._base; 109 int pgmsk = getpagesize() - 1; 110 unsigned char *_base; 111 int _size; 112 113 /* Round up to nearest page. */ 114 _size = ((blen + len + 1 + pgmsk) & ~pgmsk) - 1; 115 _base = recallocarray(fp->_bf._base, 116 fp->_bf._size + 1, _size + 1, 1); 117 if (_base == NULL) 118 goto err; 119 fp->_w += _size - fp->_bf._size; 120 fp->_bf._base = _base; 121 fp->_bf._size = _size; 122 fp->_p = _base + blen; 123 } 124 w = fp->_w; 125 if (fp->_flags & __SSTR) { 126 if (len < w) 127 w = len; 128 COPY(w); /* copy MIN(fp->_w,len), */ 129 fp->_w -= w; 130 fp->_p += w; 131 w = len; /* but pretend copied all */ 132 } else if (fp->_p > fp->_bf._base && len > w) { 133 /* fill and flush */ 134 COPY(w); 135 /* fp->_w -= w; */ /* unneeded */ 136 fp->_p += w; 137 if (__sflush(fp)) 138 goto err; 139 } else if (len >= (w = fp->_bf._size)) { 140 /* write directly */ 141 w = (*fp->_write)(fp->_cookie, p, w); 142 if (w <= 0) 143 goto err; 144 } else { 145 /* fill and done */ 146 w = len; 147 COPY(w); 148 fp->_w -= w; 149 fp->_p += w; 150 } 151 p += w; 152 len -= w; 153 } while ((uio->uio_resid -= w) != 0); 154 } else { 155 /* 156 * Line buffered: like fully buffered, but we 157 * must check for newlines. Compute the distance 158 * to the first newline (including the newline), 159 * or `infinity' if there is none, then pretend 160 * that the amount to write is MIN(len,nldist). 161 */ 162 nlknown = 0; 163 nldist = 0; /* XXX just to keep gcc happy */ 164 do { 165 GETIOV(nlknown = 0); 166 if (!nlknown) { 167 nl = memchr(p, '\n', len); 168 nldist = nl ? nl + 1 - p : len + 1; 169 nlknown = 1; 170 } 171 s = MIN(len, nldist); 172 w = fp->_w + fp->_bf._size; 173 if (fp->_p > fp->_bf._base && s > w) { 174 COPY(w); 175 /* fp->_w -= w; */ 176 fp->_p += w; 177 if (__sflush(fp)) 178 goto err; 179 } else if (s >= (w = fp->_bf._size)) { 180 w = (*fp->_write)(fp->_cookie, p, w); 181 if (w <= 0) 182 goto err; 183 } else { 184 w = s; 185 COPY(w); 186 fp->_w -= w; 187 fp->_p += w; 188 } 189 if ((nldist -= w) == 0) { 190 /* copied the newline: flush and forget */ 191 if (__sflush(fp)) 192 goto err; 193 nlknown = 0; 194 } 195 p += w; 196 len -= w; 197 } while ((uio->uio_resid -= w) != 0); 198 } 199 return (0); 200 201 err: 202 fp->_flags |= __SERR; 203 return (EOF); 204 } 205