From 0ef748fb45137bac811ded19dfad2034f924505a Mon Sep 17 00:00:00 2001
From: Joel Sherrill <joel.sherrill@OARcorp.com>
Date: Wed, 13 Dec 2000 17:53:55 +0000
Subject: 2000-12-12	Jake Janovetz <janovetz@uiuc.edu>

	*  src/imfs/linearfile.c, src/imfs/imfs_load_tar.c: New files.
	* src/imfs/Makefile.am, src/imfs/imfs.h,
	src/imfs/imfs_creat.c, src/imfs/imfs_debug.c,
	src/imfs/imfs_eval.c, src/imfs/imfs_handlers_memfile.c,
	src/imfs/imfs_init.c, src/imfs/imfs_initsupp.c,
	src/imfs/imfs_stat.c, src/imfs/miniimfs_init.c: Added "tarfs".
	This is not really a tar filesystem.  It is a way to load a tar
	image into the IMFS but actually leave bulky file contents in the
	original tar image.  It essentially adds the linear file type and
	associated support and a loader routine.
---
 c/src/libfs/src/imfs/linearfile.c | 110 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 110 insertions(+)
 create mode 100644 c/src/libfs/src/imfs/linearfile.c

(limited to 'c/src/libfs/src/imfs/linearfile.c')

diff --git a/c/src/libfs/src/imfs/linearfile.c b/c/src/libfs/src/imfs/linearfile.c
new file mode 100644
index 0000000000..e8d28fe31d
--- /dev/null
+++ b/c/src/libfs/src/imfs/linearfile.c
@@ -0,0 +1,110 @@
+/*
+ *  IMFS Linear File Handlers
+ *
+ *  This file contains the set of handlers used to process operations on
+ *  IMFS linear memory file nodes.  Linear memory files are contiguous
+ *  blocks of memory created from a TAR or other filesystem image.
+ *  The blocks are nonwriteable and nonresizeable.
+ *
+ *  COPYRIGHT (c) 1989-1999.
+ *  On-Line Applications Research Corporation (OAR).
+ *
+ *  The license and distribution terms for this file may be
+ *  found in the file LICENSE in this distribution or at
+ *  http://www.OARcorp.com/rtems/license.html.
+ *
+ *  $Id$
+ */
+
+#include <stdlib.h>
+#include <assert.h>
+#include <errno.h>
+
+#include <rtems.h>
+#include <rtems/libio.h>
+#include "imfs.h"
+#include <rtems/libio_.h>
+
+/*
+ * linearfile_read
+ *
+ *  This routine processes the read() system call.
+ */
+
+int linearfile_read(
+  rtems_libio_t *iop,
+  void          *buffer,
+  unsigned32     count
+)
+{
+  IMFS_jnode_t   *the_jnode;
+  unsigned char  *dest;
+  unsigned char  *file_ptr;
+  int            file_offset;
+
+
+  the_jnode = iop->file_info;
+
+  /*
+   *  Perform internal consistency checks
+   */
+
+  assert( the_jnode );
+  if ( !the_jnode )
+    set_errno_and_return_minus_one( EIO );
+
+  assert( the_jnode->type == IMFS_LINEAR_FILE );
+  if ( the_jnode->type != IMFS_LINEAR_FILE )
+    set_errno_and_return_minus_one( EIO );
+
+  /*
+   *  Error checks on arguments
+   */
+
+  dest = (unsigned char *)buffer;
+  assert( dest );
+  if ( !dest )
+    set_errno_and_return_minus_one( EINVAL );
+
+  /*
+   *  Perform a simple memory copy.
+   */
+
+  if (count == 0)
+     return(0);
+
+  the_jnode = iop->file_info;
+  file_ptr    = (unsigned char *)the_jnode->info.linearfile.direct;
+  file_offset = (unsigned long)iop->offset;
+
+  if (count > (the_jnode->info.linearfile.size - file_offset))
+     count = the_jnode->info.linearfile.size - file_offset;
+
+  memcpy(dest, &file_ptr[file_offset], count);
+
+  return(count);
+}
+
+
+/*
+ *  linearfile_lseek
+ *
+ *  This routine processes the lseek() system call.
+ */
+
+int linearfile_lseek(
+  rtems_libio_t   *iop,
+  off_t            offset,
+  int              whence
+)
+{
+  IMFS_jnode_t   *the_jnode;
+
+  the_jnode = iop->file_info;
+
+  if (iop->offset > the_jnode->info.linearfile.size)
+    iop->offset = the_jnode->info.linearfile.size;
+
+  return iop->offset;
+}
+
-- 
cgit v1.2.3