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<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

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><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><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> <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><title>Releated 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><title>Build</title> <p>The <xref href="GUID-3100800B-B2F7-50EF-BD4C-3C345ECCB2A5.dita">Symbian

platform 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>