<?xml version="1.0" encoding="utf-8"?>
<!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. -->
<!-- This component and the accompanying materials are made available under the terms of the License 
"Eclipse Public License v1.0" which accompanies this distribution, 
and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". -->
<!-- Initial Contributors:
    Nokia Corporation - initial contribution.
Contributors: 
-->
<!DOCTYPE concept
  PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
<concept id="GUID-3314123F-205D-5E05-9041-DB9836B7812B" xml:lang="en"><title>File
Access Example: Accessing the File System Using P.I.P.S.</title><prolog><metadata><keywords/></metadata></prolog><conbody>
<p>This example application shows, using a P.I.P.S. (P.I.P.S. Is POSIX on
the Symbian platform) program, the restrictions on file access that are imposed
by the Symbian platform Security model. </p>
<p>It shows that programs can access their own directories, but
cannot, without platform security capabilities not available to ordinary programs,
access the directories of other programs, or the system binary directory <filepath>sys/bin</filepath>. </p>
<p>This example defines an executable file with no platform security capabilities.
The program first creates its own secure directory that it can write to and
read from. It then attempts to use a file in a private directory of another
program, and then in <filepath>sys/bin</filepath>, and shows that these attempts
are denied. </p>
<section id="GUID-820F9B58-8877-414B-A18B-B591F6D67158"><title>Download</title> <p>Click
on the following link to download the example: <xref href="guid-6013a680-57f9-415b-8851-c4fa63356636/zips/guid-2dae3cca-f112-4219-8f7c-6c48682d1f28.zip" scope="external">FileAccessExample.zip</xref></p><p>Click: <xref href="guid-6013a680-57f9-415b-8851-c4fa63356636/guid-2dae3cca-f112-4219-8f7c-6c48682d1f28.html" scope="peer">browse</xref> to view the example code. </p> </section>
<section id="GUID-3EAFEC43-CFDA-4E3D-8ACD-E3AAE48BE97D"><title>Description</title> <p>The
following sections provide more information about the steps that the example
performs. </p> <p><b> Create a secure directory</b> </p> <p>The example creates
an empty secure directory for the program by using the <xref href="GUID-5EA72F64-E826-3B15-9468-902BD57F6AA7.dita"><apiname>mkdir()</apiname></xref> function. </p> <p>This
empty secure directory is created in <filepath>C:\private\E80000C9</filepath>,
as 0xE80000C9 is a unique identifier for the program (as specified by the
third UID in its project file). </p></section>
<section id="GUID-D9F306FF-D14E-4BCC-BAE6-55804F31CA0D"> <p><b>Write and read
a file in the private directory </b> </p> <p>The example writes and reads
a file in the secure directory using the <xref href="GUID-64886CC6-072F-3542-855A-5D733FC761E8.dita"><apiname>fopen()</apiname></xref> and other
file stream functions. </p> <p><b> Write and read a file in the private directory
of another program </b> </p> <p>The example attempts to write and read a file
in the secure directory of another program. </p> <p>The <xref href="GUID-64886CC6-072F-3542-855A-5D733FC761E8.dita"><apiname>fopen()</apiname></xref> function
is expected to return <codeph>NULL</codeph>, indicating that access is not
possible, as the program has insufficient platform security capabilities. </p><p><b> Write
and read a file in the sys/bin directory</b> </p> <p>The example attempts
to write and read a file in the system's <filepath>sys/bin</filepath> directory,
where program binaries are stored. </p> <p>Again, the <xref href="GUID-64886CC6-072F-3542-855A-5D733FC761E8.dita"><apiname>fopen()</apiname></xref> function
is expected to return <codeph>NULL</codeph>, indicating that access is not
possible, as the program has insufficient platform security capabilities. </p> </section>
<section id="GUID-EB4F71F2-D55D-43C5-B55F-F211D170056F"><title>Related APIs</title><p><xref href="GUID-5EA72F64-E826-3B15-9468-902BD57F6AA7.dita"><apiname>mkdir()</apiname></xref></p><p><xref href="GUID-64886CC6-072F-3542-855A-5D733FC761E8.dita"><apiname>fopen()</apiname></xref></p></section>
<section id="GUID-81AA0C7F-5D43-4EFB-9DD0-4A8A79922576"><title>Build</title> <p>The <xref href="GUID-3100800B-B2F7-50EF-BD4C-3C345ECCB2A5.dita">Symbian build process</xref> describes
how to build this example application. </p> <p>The example builds an executable
called <filepath>fileaccessexample.exe</filepath> in the standard locations. </p> <p>To
run the example, start <filepath>fileaccessexample.exe</filepath> from the
file system or from your IDE. After launching the executable, depending on
the emulator you are using, you may need to navigate away from the application
launcher or shell screen to view the console. </p> </section>
</conbody></concept>