| File: | src/lib/libc/stdio/fvwrite.c |
| Warning: | line 57, column 7 Although the value stored to 'len' is used in the enclosing expression, the value is never actually read from 'len' |
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| 1 | /* $OpenBSD: fvwrite.c,v 1.21 2023/10/06 16:41:02 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 <unistd.h> |
| 38 | #include "local.h" |
| 39 | #include "fvwrite.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 ((len = uio->uio_resid) == 0) |
Although the value stored to 'len' is used in the enclosing expression, the value is never actually read from 'len' | |
| 58 | return (0); |
| 59 | /* make sure we can write */ |
| 60 | if (cantwrite(fp)((((fp)->_flags & 0x0008) == 0 || (fp)->_bf._base == ((void *)0)) && __swsetup(fp))) |
| 61 | return (EOF(-1)); |
| 62 | |
| 63 | #define MIN(a, b)((a) < (b) ? (a) : (b)) ((a) < (b) ? (a) : (b)) |
| 64 | #define COPY(n)(void)memcpy(fp->_p, p, n) (void)memcpy(fp->_p, p, n) |
| 65 | |
| 66 | iov = uio->uio_iov; |
| 67 | p = iov->iov_base; |
| 68 | len = iov->iov_len; |
| 69 | iov++; |
| 70 | #define GETIOV(extra_work)while (len == 0) { extra_work; p = iov->iov_base; len = iov ->iov_len; iov++; } \ |
| 71 | while (len == 0) { \ |
| 72 | extra_work; \ |
| 73 | p = iov->iov_base; \ |
| 74 | len = iov->iov_len; \ |
| 75 | iov++; \ |
| 76 | } |
| 77 | if (fp->_flags & __SNBF0x0002) { |
| 78 | /* |
| 79 | * Unbuffered: write up to BUFSIZ bytes at a time. |
| 80 | */ |
| 81 | do { |
| 82 | GETIOV(;)while (len == 0) { ;; p = iov->iov_base; len = iov->iov_len ; iov++; }; |
| 83 | w = (*fp->_write)(fp->_cookie, p, MIN(len, BUFSIZ)((len) < (1024) ? (len) : (1024))); |
| 84 | if (w <= 0) |
| 85 | goto err; |
| 86 | p += w; |
| 87 | len -= w; |
| 88 | } while ((uio->uio_resid -= w) != 0); |
| 89 | } else if ((fp->_flags & __SLBF0x0001) == 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(;)while (len == 0) { ;; p = iov->iov_base; len = iov->iov_len ; iov++; }; |
| 103 | if ((fp->_flags & (__SALC0x4000 | __SSTR0x0200)) == |
| 104 | (__SALC0x4000 | __SSTR0x0200) && fp->_w < len) { |
| 105 | size_t blen = fp->_p - fp->_bf._base; |
| 106 | int pgmsk = getpagesize() - 1; |
| 107 | unsigned char *_base; |
| 108 | int _size; |
| 109 | |
| 110 | /* Round up to nearest page. */ |
| 111 | _size = ((blen + len + 1 + pgmsk) & ~pgmsk) - 1; |
| 112 | _base = recallocarray(fp->_bf._base, |
| 113 | fp->_bf._size + 1, _size + 1, 1); |
| 114 | if (_base == NULL((void *)0)) |
| 115 | goto err; |
| 116 | fp->_w += _size - fp->_bf._size; |
| 117 | fp->_bf._base = _base; |
| 118 | fp->_bf._size = _size; |
| 119 | fp->_p = _base + blen; |
| 120 | } |
| 121 | w = fp->_w; |
| 122 | if (fp->_flags & __SSTR0x0200) { |
| 123 | if (len < w) |
| 124 | w = len; |
| 125 | COPY(w)(void)memcpy(fp->_p, p, w); /* copy MIN(fp->_w,len), */ |
| 126 | fp->_w -= w; |
| 127 | fp->_p += w; |
| 128 | w = len; /* but pretend copied all */ |
| 129 | } else if (fp->_p > fp->_bf._base && len > w) { |
| 130 | /* fill and flush */ |
| 131 | COPY(w)(void)memcpy(fp->_p, p, w); |
| 132 | /* fp->_w -= w; */ /* unneeded */ |
| 133 | fp->_p += w; |
| 134 | if (__sflush(fp)) |
| 135 | goto err; |
| 136 | } else if (len >= (w = fp->_bf._size)) { |
| 137 | /* write directly */ |
| 138 | w = (*fp->_write)(fp->_cookie, p, w); |
| 139 | if (w <= 0) |
| 140 | goto err; |
| 141 | } else { |
| 142 | /* fill and done */ |
| 143 | w = len; |
| 144 | COPY(w)(void)memcpy(fp->_p, p, w); |
| 145 | fp->_w -= w; |
| 146 | fp->_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)while (len == 0) { nlknown = 0; p = iov->iov_base; len = iov ->iov_len; iov++; }; |
| 163 | if (!nlknown) { |
| 164 | nl = memchr(p, '\n', len); |
| 165 | nldist = nl ? nl + 1 - p : len + 1; |
| 166 | nlknown = 1; |
| 167 | } |
| 168 | s = MIN(len, nldist)((len) < (nldist) ? (len) : (nldist)); |
| 169 | w = fp->_w + fp->_bf._size; |
| 170 | if (fp->_p > fp->_bf._base && s > w) { |
| 171 | COPY(w)(void)memcpy(fp->_p, p, w); |
| 172 | /* fp->_w -= w; */ |
| 173 | fp->_p += w; |
| 174 | if (__sflush(fp)) |
| 175 | goto err; |
| 176 | } else if (s >= (w = fp->_bf._size)) { |
| 177 | w = (*fp->_write)(fp->_cookie, p, w); |
| 178 | if (w <= 0) |
| 179 | goto err; |
| 180 | } else { |
| 181 | w = s; |
| 182 | COPY(w)(void)memcpy(fp->_p, p, w); |
| 183 | fp->_w -= w; |
| 184 | fp->_p += w; |
| 185 | } |
| 186 | if ((nldist -= w) == 0) { |
| 187 | /* copied the newline: flush and forget */ |
| 188 | if (__sflush(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->_flags |= __SERR0x0040; |
| 200 | return (EOF(-1)); |
| 201 | } |