lib/libc/stdio/stdio.c

   1 /*      $NetBSD: stdio.c,v 1.22 2013/05/19 17:07:04 christos Exp $      */
   2
   3 /*-
   4  * Copyright (c) 1990, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * This code is derived from software contributed to Berkeley by
   8  * Chris Torek.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. Neither the name of the University nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  */
  34
  35 #include <sys/cdefs.h>
  36 #if defined(LIBC_SCCS) && !defined(lint)
  37 #if 0
  38 static char sccsid[] = "@(#)stdio.c     8.1 (Berkeley) 6/4/93";
  39 #else
  40 __RCSID("$NetBSD: stdio.c,v 1.22 2013/05/19 17:07:04 christos Exp $");
  41 #endif
  42 #endif /* LIBC_SCCS and not lint */
  43
  44 #include "namespace.h"
  45
  46 #include <assert.h>
  47 #include <errno.h>
  48 #include <fcntl.h>
  49 #include <stdio.h>
  50 #include <unistd.h>
  51
  52 #include "reentrant.h"
  53 #include "local.h"
  54
  55 /*
  56  * Small standard I/O/seek/close functions.
  57  * These maintain the `known seek offset' for seek optimisation.
  58  */
  59 ssize_t
  60 __sread(void *cookie, void *buf, size_t n)
  61 {
  62         FILE *fp = cookie;
  63         ssize_t ret;
  64
  65         _DIAGASSERT(cookie != NULL);
  66         _DIAGASSERT(cookie == fp->_cookie);
  67         _DIAGASSERT(buf != NULL);
  68
  69         ret = read(__sfileno(fp), buf, n);
  70         /* if the read succeeded, update the current offset */
  71         if (ret >= 0)
  72                 fp->_offset += ret;
  73         else
  74                 fp->_flags &= ~__SOFF;  /* paranoia */
  75
  76         return ret;
  77 }
  78
  79 ssize_t
  80 __swrite(void *cookie, const void *buf, size_t n)
  81 {
  82         FILE *fp = cookie;
  83
  84         _DIAGASSERT(cookie != NULL);
  85         _DIAGASSERT(cookie == fp->_cookie);
  86         _DIAGASSERT(buf != NULL);
  87
  88         if (fp->_flags & __SAPP)
  89                 if (lseek(__sfileno(fp), (off_t)0, SEEK_END) == (off_t)-1) {
  90                         if (errno == ESPIPE)            /* if unseekable, OK, */
  91                                 fp->_flags &= ~__SAPP;  /* all writes append. */
  92                         else
  93                                 return -1;
  94                 }
  95         fp->_flags &= ~__SOFF;  /* in case FAPPEND mode is set */
  96         return write(__sfileno(fp), buf, n);
  97 }
  98
  99 off_t
 100 __sseek(void *cookie, off_t offset, int whence)
 101 {
 102         FILE *fp = cookie;
 103         off_t ret;
 104
 105         _DIAGASSERT(cookie != NULL);
 106         _DIAGASSERT(cookie == fp->_cookie);
 107
 108         ret = lseek(__sfileno(fp), offset, whence);
 109         if (ret == (off_t)-1L)
 110                 fp->_flags &= ~__SOFF;
 111         else {
 112                 fp->_flags |= __SOFF;
 113                 fp->_offset = ret;
 114         }
 115         return ret;
 116 }
 117
 118 int
 119 __sclose(void *cookie)
 120 {
 121         FILE *fp = cookie;
 122
 123         _DIAGASSERT(cookie != NULL);
 124         _DIAGASSERT(cookie == fp->_cookie);
 125
 126         return close(__sfileno(fp));
 127 }