fvwrite.c (6147B)
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 rcsid[] = "$OpenBSD: fvwrite.c,v 1.7 1998/08/14 21:39:40 deraadt Exp $"; 39 #endif /* LIBC_SCCS and not lint */ 40 41 #include <stdio.h> 42 #include <stdlib.h> 43 #include <string.h> 44 #include <errno.h> 45 #include "local.h" 46 #include "fvwrite.h" 47 48 /* 49 * Write some memory regions. Return zero on success, EOF on error. 50 * 51 * This routine is large and unsightly, but most of the ugliness due 52 * to the three different kinds of output buffering is handled here. 53 */ 54 int 55 __sfvwrite(fp, uio) 56 register FILE *fp; 57 register struct __suio *uio; 58 { 59 register size_t len; 60 register char *p; 61 register struct __siov *iov; 62 register int w, s; 63 char *nl; 64 int nlknown, nldist; 65 66 if ((len = uio->uio_resid) == 0) 67 return (0); 68 /* make sure we can write */ 69 if (cantwrite(fp)) { 70 errno = EBADF; 71 return (EOF); 72 } 73 74 #define MIN(a, b) ((a) < (b) ? (a) : (b)) 75 #define COPY(n) (void)memcpy((void *)fp->_p, (void *)p, (size_t)(n)) 76 77 iov = uio->uio_iov; 78 p = iov->iov_base; 79 len = iov->iov_len; 80 iov++; 81 #define GETIOV(extra_work) \ 82 while (len == 0) { \ 83 extra_work; \ 84 p = iov->iov_base; \ 85 len = iov->iov_len; \ 86 iov++; \ 87 } 88 if (fp->_flags & __SNBF) { 89 /* 90 * Unbuffered: write up to BUFSIZ bytes at a time. 91 */ 92 do { 93 GETIOV(;); 94 w = (*fp->_write)(fp->_cookie, p, MIN(len, BUFSIZ)); 95 if (w <= 0) 96 goto err; 97 p += w; 98 len -= w; 99 } while ((uio->uio_resid -= w) != 0); 100 } else if ((fp->_flags & __SLBF) == 0) { 101 /* 102 * Fully buffered: fill partially full buffer, if any, 103 * and then flush. If there is no partial buffer, write 104 * one _bf._size byte chunk directly (without copying). 105 * 106 * String output is a special case: write as many bytes 107 * as fit, but pretend we wrote everything. This makes 108 * snprintf() return the number of bytes needed, rather 109 * than the number used, and avoids its write function 110 * (so that the write function can be invalid). 111 */ 112 do { 113 GETIOV(;); 114 if ((fp->_flags & (__SALC | __SSTR)) == 115 (__SALC | __SSTR) && fp->_w < len) { 116 size_t blen = fp->_p - fp->_bf._base; 117 unsigned char *_base; 118 119 /* 120 * Alloc an extra 128 bytes (+ 1 for NULL) 121 * so we don't call realloc(3) so often. 122 */ 123 fp->_w = len + 128; 124 fp->_bf._size = blen + len + 128; 125 _base = realloc(fp->_bf._base, fp->_bf._size + 1); 126 if (_base == NULL) 127 goto err; 128 fp->_bf._base = _base; 129 fp->_p = fp->_bf._base + blen; 130 } 131 w = fp->_w; 132 if (fp->_flags & __SSTR) { 133 if (len < w) 134 w = len; 135 COPY(w); /* copy MIN(fp->_w,len), */ 136 fp->_w -= w; 137 fp->_p += w; 138 w = len; /* but pretend copied all */ 139 } else if (fp->_p > fp->_bf._base && len > w) { 140 /* fill and flush */ 141 COPY(w); 142 /* fp->_w -= w; */ /* unneeded */ 143 fp->_p += w; 144 if (fflush(fp)) 145 goto err; 146 } else if (len >= (w = fp->_bf._size)) { 147 /* write directly */ 148 w = (*fp->_write)(fp->_cookie, p, w); 149 if (w <= 0) 150 goto err; 151 } else { 152 /* fill and done */ 153 w = len; 154 COPY(w); 155 fp->_w -= w; 156 fp->_p += w; 157 } 158 p += w; 159 len -= w; 160 } while ((uio->uio_resid -= w) != 0); 161 } else { 162 /* 163 * Line buffered: like fully buffered, but we 164 * must check for newlines. Compute the distance 165 * to the first newline (including the newline), 166 * or `infinity' if there is none, then pretend 167 * that the amount to write is MIN(len,nldist). 168 */ 169 nlknown = 0; 170 nldist = 0; /* XXX just to keep gcc happy */ 171 do { 172 GETIOV(nlknown = 0); 173 if (!nlknown) { 174 nl = memchr((void *)p, '\n', len); 175 nldist = nl ? nl + 1 - p : len + 1; 176 nlknown = 1; 177 } 178 s = MIN(len, nldist); 179 w = fp->_w + fp->_bf._size; 180 if (fp->_p > fp->_bf._base && s > w) { 181 COPY(w); 182 /* fp->_w -= w; */ 183 fp->_p += w; 184 if (fflush(fp)) 185 goto err; 186 } else if (s >= (w = fp->_bf._size)) { 187 w = (*fp->_write)(fp->_cookie, p, w); 188 if (w <= 0) 189 goto err; 190 } else { 191 w = s; 192 COPY(w); 193 fp->_w -= w; 194 fp->_p += w; 195 } 196 if ((nldist -= w) == 0) { 197 /* copied the newline: flush and forget */ 198 if (fflush(fp)) 199 goto err; 200 nlknown = 0; 201 } 202 p += w; 203 len -= w; 204 } while ((uio->uio_resid -= w) != 0); 205 } 206 return (0); 207 208 err: 209 fp->_flags |= __SERR; 210 return (EOF); 211 }