src/system/libroot/posix/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. 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 #include <ktypes.h>
  38 #include <fcntl.h>
  39 #include <unistd.h>
  40 #include <stdio.h>
  41 #include "local.h"
  42
  43 /*
  44  * Small standard I/O/seek/close functions.
  45  * These maintain the `known seek offset' for seek optimisation.
  46  */
  47 int
  48 __sread(cookie, buf, n)
  49         void *cookie;
  50         char *buf;
  51         int n;
  52 {
  53         register FILE *fp = cookie;
  54         register int ret;
  55
  56         ret = read(fp->_file, buf, n);
  57         /* if the read succeeded, update the current offset */
  58         if (ret >= 0)
  59                 fp->_offset += ret;
  60         else
  61                 fp->_flags &= ~__SOFF;  /* paranoia */
  62         return (ret);
  63 }
  64
  65 int
  66 __swrite(cookie, buf, n)
  67         void *cookie;
  68         char const *buf;
  69         int n;
  70 {
  71         register FILE *fp = cookie;
  72
  73         if (fp->_flags & __SAPP)
  74                 (void) lseek(fp->_file, (off_t)0, SEEK_END);
  75         fp->_flags &= ~__SOFF;  /* in case FAPPEND mode is set */
  76
  77         return (write(fp->_file, buf, n));
  78 }
  79
  80 fpos_t
  81 __sseek(cookie, offset, whence)
  82         void *cookie;
  83         fpos_t offset;
  84         int whence;
  85 {
  86         register FILE *fp = cookie;
  87         register off_t ret;
  88
  89         ret = lseek(fp->_file, (off_t)offset, whence);
  90         if (ret == (off_t)-1)
  91                 fp->_flags &= ~__SOFF;
  92         else {
  93                 fp->_flags |= __SOFF;
  94                 fp->_offset = ret;
  95         }
  96         return (ret);
  97 }
  98
  99 int
 100 __sclose(cookie)
 101         void *cookie;
 102 {
 103         return (close(((FILE *)cookie)->_file));
 104 }