| 1 | /* $OpenBSD: fvwrite.c,v 1.16 2009/10/22 01:23:16 guenther Exp $ */ |
| 2 | /* |
| 3 | * SPDX-License-Identifier: BSD-3-Clause |
| 4 | * |
| 5 | * Copyright (C) 1990, 1993 |
| 6 | * The Regents of the University of California. All rights reserved. |
| 7 | * |
| 8 | * This code is derived from software contributed to Berkeley by |
| 9 | * Chris Torek. |
| 10 | */ |
| 11 | |
| 12 | #include <stdio.h> |
| 13 | #include <stdlib.h> |
| 14 | #include <string.h> |
| 15 | #include <errno.h> |
| 16 | #include "local.h" |
| 17 | #include "fvwrite.h" |
| 18 | #include "various.h" |
| 19 | |
| 20 | /* |
| 21 | * Write some memory regions. Return zero on success, EOF on error. |
| 22 | * |
| 23 | * This routine is large and unsightly, but most of the ugliness due |
| 24 | * to the three different kinds of output buffering is handled here. |
| 25 | */ |
| 26 | int |
| 27 | __sfvwrite(LTTNG_UST_LFILE *fp, struct __lttng_ust_suio *uio) |
| 28 | { |
| 29 | size_t len; |
| 30 | char *p; |
| 31 | struct __lttng_ust_siov *iov; |
| 32 | int w, s; |
| 33 | char *nl; |
| 34 | int nlknown, nldist; |
| 35 | |
| 36 | if ((len = uio->uio_resid) == 0) |
| 37 | return (0); |
| 38 | /* make sure we can write */ |
| 39 | if (cantwrite(fp)) { |
| 40 | errno = EBADF; |
| 41 | return (EOF); |
| 42 | } |
| 43 | |
| 44 | #define MIN(a, b) ((a) < (b) ? (a) : (b)) |
| 45 | #define COPY(n) (void)memcpy((void *)fp->_p, (void *)p, (size_t)(n)) |
| 46 | |
| 47 | iov = uio->uio_iov; |
| 48 | p = iov->iov_base; |
| 49 | len = iov->iov_len; |
| 50 | iov++; |
| 51 | #define GETIOV(extra_work) \ |
| 52 | while (len == 0) { \ |
| 53 | extra_work; \ |
| 54 | p = iov->iov_base; \ |
| 55 | len = iov->iov_len; \ |
| 56 | iov++; \ |
| 57 | } |
| 58 | if (fp->_flags & __SNBF) { |
| 59 | /* |
| 60 | * Unbuffered: write up to BUFSIZ bytes at a time. |
| 61 | */ |
| 62 | do { |
| 63 | GETIOV(;); |
| 64 | w = (*fp->_write)(fp->_cookie, p, MIN(len, BUFSIZ)); |
| 65 | if (w <= 0) |
| 66 | goto err; |
| 67 | p += w; |
| 68 | len -= w; |
| 69 | } while ((uio->uio_resid -= w) != 0); |
| 70 | } else if ((fp->_flags & __SLBF) == 0) { |
| 71 | /* |
| 72 | * Fully buffered: fill partially full buffer, if any, |
| 73 | * and then flush. If there is no partial buffer, write |
| 74 | * one _bf._size byte chunk directly (without copying). |
| 75 | * |
| 76 | * String output is a special case: write as many bytes |
| 77 | * as fit, but pretend we wrote everything. This makes |
| 78 | * snprintf() return the number of bytes needed, rather |
| 79 | * than the number used, and avoids its write function |
| 80 | * (so that the write function can be invalid). |
| 81 | */ |
| 82 | do { |
| 83 | GETIOV(;); |
| 84 | if ((fp->_flags & (__SALC | __SSTR)) == |
| 85 | (__SALC | __SSTR) && fp->_w < len) { |
| 86 | size_t blen = fp->_p - fp->_bf._base; |
| 87 | unsigned char *_base; |
| 88 | int _size; |
| 89 | |
| 90 | /* Allocate space exponentially. */ |
| 91 | _size = fp->_bf._size; |
| 92 | do { |
| 93 | _size = (_size << 1) + 1; |
| 94 | } while (_size < blen + len); |
| 95 | _base = realloc(fp->_bf._base, _size + 1); |
| 96 | if (_base == NULL) |
| 97 | goto err; |
| 98 | fp->_w += _size - fp->_bf._size; |
| 99 | fp->_bf._base = _base; |
| 100 | fp->_bf._size = _size; |
| 101 | fp->_p = _base + blen; |
| 102 | } |
| 103 | w = fp->_w; |
| 104 | if (fp->_flags & __SSTR) { |
| 105 | if (len < w) |
| 106 | w = len; |
| 107 | COPY(w); /* copy MIN(fp->_w,len), */ |
| 108 | fp->_w -= w; |
| 109 | fp->_p += w; |
| 110 | w = len; /* but pretend copied all */ |
| 111 | } else if (fp->_p > fp->_bf._base && len > w) { |
| 112 | /* fill and flush */ |
| 113 | COPY(w); |
| 114 | /* fp->_w -= w; */ /* unneeded */ |
| 115 | fp->_p += w; |
| 116 | if (ust_safe_fflush(fp)) |
| 117 | goto err; |
| 118 | } else if (len >= (w = fp->_bf._size)) { |
| 119 | /* write directly */ |
| 120 | w = (*fp->_write)(fp->_cookie, p, w); |
| 121 | if (w <= 0) |
| 122 | goto err; |
| 123 | } else { |
| 124 | /* fill and done */ |
| 125 | w = len; |
| 126 | COPY(w); |
| 127 | fp->_w -= w; |
| 128 | fp->_p += w; |
| 129 | } |
| 130 | p += w; |
| 131 | len -= w; |
| 132 | } while ((uio->uio_resid -= w) != 0); |
| 133 | } else { |
| 134 | /* |
| 135 | * Line buffered: like fully buffered, but we |
| 136 | * must check for newlines. Compute the distance |
| 137 | * to the first newline (including the newline), |
| 138 | * or `infinity' if there is none, then pretend |
| 139 | * that the amount to write is MIN(len,nldist). |
| 140 | */ |
| 141 | nlknown = 0; |
| 142 | nldist = 0; /* XXX just to keep gcc happy */ |
| 143 | do { |
| 144 | GETIOV(nlknown = 0); |
| 145 | if (!nlknown) { |
| 146 | nl = memchr((void *)p, '\n', len); |
| 147 | nldist = nl ? nl + 1 - p : len + 1; |
| 148 | nlknown = 1; |
| 149 | } |
| 150 | s = MIN(len, nldist); |
| 151 | w = fp->_w + fp->_bf._size; |
| 152 | if (fp->_p > fp->_bf._base && s > w) { |
| 153 | COPY(w); |
| 154 | /* fp->_w -= w; */ |
| 155 | fp->_p += w; |
| 156 | if (ust_safe_fflush(fp)) |
| 157 | goto err; |
| 158 | } else if (s >= (w = fp->_bf._size)) { |
| 159 | w = (*fp->_write)(fp->_cookie, p, w); |
| 160 | if (w <= 0) |
| 161 | goto err; |
| 162 | } else { |
| 163 | w = s; |
| 164 | COPY(w); |
| 165 | fp->_w -= w; |
| 166 | fp->_p += w; |
| 167 | } |
| 168 | if ((nldist -= w) == 0) { |
| 169 | /* copied the newline: flush and forget */ |
| 170 | if (ust_safe_fflush(fp)) |
| 171 | goto err; |
| 172 | nlknown = 0; |
| 173 | } |
| 174 | p += w; |
| 175 | len -= w; |
| 176 | } while ((uio->uio_resid -= w) != 0); |
| 177 | } |
| 178 | return (0); |
| 179 | |
| 180 | err: |
| 181 | fp->_flags |= __SERR; |
| 182 | return (EOF); |
| 183 | } |