lib/libc/stdio/stdio.c

   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. Neither the name of the University nor the names of its contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  *
  32  * @(#)stdio.c  8.1 (Berkeley) 6/4/93
  33  * $FreeBSD: src/lib/libc/stdio/stdio.c,v 1.28 2008/05/05 16:14:02 jhb Exp $
  34  */
  35
  36 #include "namespace.h"
  37 #include <errno.h>
  38 #include <fcntl.h>
  39 #include <limits.h>
  40 #include <stdio.h>
  41 #include <stdlib.h>
  42 #include <unistd.h>
  43 #include "un-namespace.h"
  44 #include "local.h"
  45
  46 /*
  47  * Small standard I/O/seek/close functions.
  48  */
  49 int
  50 __sread(void *cookie, char *buf, int n)
  51 {
  52         FILE *fp = cookie;
  53
  54         return(_read(fp->pub._fileno, buf, (size_t)n));
  55 }
  56
  57 int
  58 __swrite(void *cookie, const char *buf, int n)
  59 {
  60         FILE *fp = cookie;
  61
  62         return (_write(fp->pub._fileno, buf, (size_t)n));
  63 }
  64
  65 fpos_t
  66 __sseek(void *cookie, fpos_t offset, int whence)
  67 {
  68         FILE *fp = cookie;
  69
  70         return (lseek(fp->pub._fileno, (off_t)offset, whence));
  71 }
  72
  73 int
  74 __sclose(void *cookie)
  75 {
  76
  77         return (_close(((FILE *)cookie)->pub._fileno));
  78 }
  79
  80 /*
  81  * Higher level wrappers.
  82  */
  83 int
  84 _sread(FILE *fp, char *buf, int n)
  85 {
  86         int ret;
  87
  88         ret = (*fp->_read)(fp->_cookie, buf, n);
  89         if (ret > 0) {
  90                 if (fp->pub._flags & __SOFF) {
  91                         if (fp->_offset <= OFF_MAX - ret)
  92                                 fp->_offset += ret;
  93                         else
  94                                 fp->pub._flags &= ~__SOFF;
  95                 }
  96         } else if (ret < 0)
  97                 fp->pub._flags &= ~__SOFF;
  98         return (ret);
  99 }
 100
 101 int
 102 _swrite(FILE *fp, const char *buf, int n)
 103 {
 104         int ret;
 105         int serrno;
 106
 107         if (fp->pub._flags & __SAPP) {
 108                 serrno = errno;
 109                 if (_sseek(fp, (fpos_t)0, SEEK_END) == -1 &&
 110                     (fp->pub._flags & __SOPT))
 111                         return (-1);
 112                 errno = serrno;
 113         }
 114         ret = (*fp->_write)(fp->_cookie, buf, n);
 115         /* __SOFF removed even on success in case O_APPEND mode is set. */
 116         if (ret >= 0) {
 117                 if ((fp->pub._flags & (__SAPP|__SOFF)) == (__SAPP|__SOFF) &&
 118                     fp->_offset <= OFF_MAX - ret)
 119                         fp->_offset += ret;
 120                 else
 121                         fp->pub._flags &= ~__SOFF;
 122
 123         } else if (ret < 0)
 124                 fp->pub._flags &= ~__SOFF;
 125         return (ret);
 126 }
 127
 128 fpos_t
 129 _sseek(FILE *fp, fpos_t offset, int whence)
 130 {
 131         fpos_t ret;
 132         int serrno, errret;
 133
 134         serrno = errno;
 135         errno = 0;
 136         ret = (*fp->_seek)(fp->_cookie, offset, whence);
 137         errret = errno;
 138         if (errno == 0)
 139                 errno = serrno;
 140         /*
 141          * Disallow negative seeks per POSIX.
 142          * It is needed here to help upper level caller
 143          * in the cases it can't detect.
 144          */
 145         if (ret < 0) {
 146                 if (errret == 0) {
 147                         if (offset != 0 || whence != SEEK_CUR) {
 148                                 if (HASUB(fp))
 149                                         FREEUB(fp);
 150                                 fp->pub._p = fp->_bf._base;
 151                                 fp->pub._r = 0;
 152                                 fp->pub._flags &= ~__SEOF;
 153                         }
 154                         fp->pub._flags |= __SERR;
 155                         errno = EINVAL;
 156                 } else if (errret == ESPIPE)
 157                         fp->pub._flags &= ~__SAPP;
 158                 fp->pub._flags &= ~__SOFF;
 159                 ret = -1;
 160         } else if (fp->pub._flags & __SOPT) {
 161                 fp->pub._flags |= __SOFF;
 162                 fp->_offset = ret;
 163         }
 164         return (ret);
 165 }