source: rtems/c/src/exec/libfs/src/imfs/linearfile.c @ d6b1d73

4.104.114.84.95
Last change on this file since d6b1d73 was d6b1d73, checked in by Joel Sherrill <joel.sherrill@…>, on 01/22/01 at 14:05:14

2001-01-22 Ralf Corsepius <corsepiu@…>

  • configure.in: Add src/imfs/config.h
  • src/imfs/Makefile.am: Add INCLUDES += -I. to pickup config.h
  • src/imfs/.cvsignore: Add config.h and stamp-h
  • src/imfs/*.c: Add config.h support.
  • Property mode set to 100644
File size: 2.3 KB
Line 
1/*
2 *  IMFS Linear File Handlers
3 *
4 *  This file contains the set of handlers used to process operations on
5 *  IMFS linear memory file nodes.  Linear memory files are contiguous
6 *  blocks of memory created from a TAR or other filesystem image.
7 *  The blocks are nonwriteable and nonresizeable.
8 *
9 *  COPYRIGHT (c) 1989-1999.
10 *  On-Line Applications Research Corporation (OAR).
11 *
12 *  The license and distribution terms for this file may be
13 *  found in the file LICENSE in this distribution or at
14 *  http://www.OARcorp.com/rtems/license.html.
15 *
16 *  $Id$
17 */
18
19#if HAVE_CONFIG_H
20#include "config.h"
21#endif
22
23#include <stdlib.h>
24#include <assert.h>
25#include <errno.h>
26
27#include <rtems.h>
28#include <rtems/libio.h>
29#include "imfs.h"
30#include <rtems/libio_.h>
31
32/*
33 * linearfile_read
34 *
35 *  This routine processes the read() system call.
36 */
37
38int linearfile_read(
39  rtems_libio_t *iop,
40  void          *buffer,
41  unsigned32     count
42)
43{
44  IMFS_jnode_t   *the_jnode;
45  unsigned char  *dest;
46  unsigned char  *file_ptr;
47  int            file_offset;
48
49
50  the_jnode = iop->file_info;
51
52  /*
53   *  Perform internal consistency checks
54   */
55
56  assert( the_jnode );
57  if ( !the_jnode )
58    set_errno_and_return_minus_one( EIO );
59
60  assert( the_jnode->type == IMFS_LINEAR_FILE );
61  if ( the_jnode->type != IMFS_LINEAR_FILE )
62    set_errno_and_return_minus_one( EIO );
63
64  /*
65   *  Error checks on arguments
66   */
67
68  dest = (unsigned char *)buffer;
69  assert( dest );
70  if ( !dest )
71    set_errno_and_return_minus_one( EINVAL );
72
73  /*
74   *  Perform a simple memory copy.
75   */
76
77  if (count == 0)
78     return(0);
79
80  the_jnode = iop->file_info;
81  file_ptr    = (unsigned char *)the_jnode->info.linearfile.direct;
82  file_offset = (unsigned long)iop->offset;
83
84  if (count > (the_jnode->info.linearfile.size - file_offset))
85     count = the_jnode->info.linearfile.size - file_offset;
86
87  memcpy(dest, &file_ptr[file_offset], count);
88
89  return(count);
90}
91
92
93/*
94 *  linearfile_lseek
95 *
96 *  This routine processes the lseek() system call.
97 */
98
99int linearfile_lseek(
100  rtems_libio_t   *iop,
101  off_t            offset,
102  int              whence
103)
104{
105  IMFS_jnode_t   *the_jnode;
106
107  the_jnode = iop->file_info;
108
109  if (iop->offset > the_jnode->info.linearfile.size)
110    iop->offset = the_jnode->info.linearfile.size;
111
112  return iop->offset;
113}
114
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