1 /* $NetBSD: fvwrite.c,v 1.21 2009/10/25 20:44:13 christos Exp $ */ 2 3 /*- 4 * Copyright (c) 1990, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Chris Torek. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 #include <sys/cdefs.h> 36 #if defined(LIBC_SCCS) && !defined(lint) 37 #if 0 38 static char sccsid[] = "@(#)fvwrite.c 8.1 (Berkeley) 6/4/93"; 39 #else 40 __RCSID("$NetBSD: fvwrite.c,v 1.21 2009/10/25 20:44:13 christos Exp $"); 41 #endif 42 #endif /* LIBC_SCCS and not lint */ 43 44 #include <assert.h> 45 #include <errno.h> 46 #include <stdio.h> 47 #include <stdlib.h> 48 #include <string.h> 49 #include "reentrant.h" 50 #include "local.h" 51 #include "fvwrite.h" 52 53 /* 54 * Write some memory regions. Return zero on success, EOF on error. 55 * 56 * This routine is large and unsightly, but most of the ugliness due 57 * to the three different kinds of output buffering is handled here. 58 */ 59 int 60 __sfvwrite(fp, uio) 61 FILE *fp; 62 struct __suio *uio; 63 { 64 int len; 65 char *p; 66 struct __siov *iov; 67 int w, s; 68 char *nl; 69 int nlknown, nldist; 70 71 _DIAGASSERT(fp != NULL); 72 _DIAGASSERT(uio != NULL); 73 74 if ((int)uio->uio_resid < 0) { 75 errno = EINVAL; 76 return (EOF); 77 } 78 if ((len = uio->uio_resid) == 0) 79 return (0); 80 /* make sure we can write */ 81 if (cantwrite(fp)) { 82 errno = EBADF; 83 return (EOF); 84 } 85 86 #define MIN(a, b) ((a) < (b) ? (a) : (b)) 87 #define COPY(n) (void)memcpy(fp->_p, p, (size_t)(n)) 88 89 iov = uio->uio_iov; 90 p = iov->iov_base; 91 len = iov->iov_len; 92 iov++; 93 #define GETIOV(extra_work) \ 94 while (len == 0) { \ 95 extra_work; \ 96 p = iov->iov_base; \ 97 len = iov->iov_len; \ 98 iov++; \ 99 } 100 if (fp->_flags & __SNBF) { 101 /* 102 * Unbuffered: write up to BUFSIZ bytes at a time. 103 */ 104 do { 105 GETIOV(;); 106 w = (*fp->_write)(fp->_cookie, p, 107 (int)MIN(len, BUFSIZ)); 108 if (w <= 0) 109 goto err; 110 p += w; 111 len -= w; 112 } while ((uio->uio_resid -= w) != 0); 113 } else if ((fp->_flags & __SLBF) == 0) { 114 /* 115 * Fully buffered: fill partially full buffer, if any, 116 * and then flush. If there is no partial buffer, write 117 * one _bf._size byte chunk directly (without copying). 118 * 119 * String output is a special case: write as many bytes 120 * as fit, but pretend we wrote everything. This makes 121 * snprintf() return the number of bytes needed, rather 122 * than the number used, and avoids its write function 123 * (so that the write function can be invalid). 124 */ 125 do { 126 GETIOV(;); 127 if ((fp->_flags & (__SALC | __SSTR)) == 128 (__SALC | __SSTR) && fp->_w < len) { 129 int blen = fp->_p - fp->_bf._base; 130 unsigned char *_base; 131 int _size; 132 133 /* Allocate space exponentially. */ 134 _size = fp->_bf._size; 135 do { 136 _size = (_size << 1) + 1; 137 } while (_size < blen + len); 138 _base = realloc(fp->_bf._base, 139 (size_t)(_size + 1)); 140 if (_base == NULL) 141 goto err; 142 fp->_w += _size - fp->_bf._size; 143 fp->_bf._base = _base; 144 fp->_bf._size = _size; 145 fp->_p = _base + blen; 146 } 147 w = fp->_w; 148 if (fp->_flags & __SSTR) { 149 if (len < w) 150 w = len; 151 COPY(w); /* copy MIN(fp->_w,len), */ 152 fp->_w -= w; 153 fp->_p += w; 154 w = len; /* but pretend copied all */ 155 } else if (fp->_p > fp->_bf._base && len > w) { 156 /* fill and flush */ 157 COPY(w); 158 /* fp->_w -= w; */ /* unneeded */ 159 fp->_p += w; 160 if (fflush(fp)) 161 goto err; 162 } else if (len >= (w = fp->_bf._size)) { 163 /* write directly */ 164 w = (*fp->_write)(fp->_cookie, p, w); 165 if (w <= 0) 166 goto err; 167 } else { 168 /* fill and done */ 169 w = len; 170 COPY(w); 171 fp->_w -= w; 172 fp->_p += w; 173 } 174 p += w; 175 len -= w; 176 } while ((uio->uio_resid -= w) != 0); 177 } else { 178 /* 179 * Line buffered: like fully buffered, but we 180 * must check for newlines. Compute the distance 181 * to the first newline (including the newline), 182 * or `infinity' if there is none, then pretend 183 * that the amount to write is MIN(len,nldist). 184 */ 185 nlknown = 0; 186 nldist = 0; /* XXX just to keep gcc happy */ 187 do { 188 GETIOV(nlknown = 0); 189 if (!nlknown) { 190 nl = memchr(p, '\n', (size_t)len); 191 nldist = nl ? nl + 1 - p : len + 1; 192 nlknown = 1; 193 } 194 s = MIN(len, nldist); 195 w = fp->_w + fp->_bf._size; 196 if (fp->_p > fp->_bf._base && s > w) { 197 COPY(w); 198 /* fp->_w -= w; */ 199 fp->_p += w; 200 if (fflush(fp)) 201 goto err; 202 } else if (s >= (w = fp->_bf._size)) { 203 w = (*fp->_write)(fp->_cookie, p, w); 204 if (w <= 0) 205 goto err; 206 } else { 207 w = s; 208 COPY(w); 209 fp->_w -= w; 210 fp->_p += w; 211 } 212 if ((nldist -= w) == 0) { 213 /* copied the newline: flush and forget */ 214 if (fflush(fp)) 215 goto err; 216 nlknown = 0; 217 } 218 p += w; 219 len -= w; 220 } while ((uio->uio_resid -= w) != 0); 221 } 222 return (0); 223 224 err: 225 fp->_flags |= __SERR; 226 return (EOF); 227 } 228