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    10 <!DOCTYPE concept

    11   PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">

    12 <concept id="GUID-3314123F-205D-5E05-9041-DB9836B7812B" xml:lang="en"><title>File

    13 Access Example: Accessing the File System Using P.I.P.S.</title><prolog><metadata><keywords/></metadata></prolog><conbody>

    14 <p>This example application shows, using a P.I.P.S. (P.I.P.S. Is POSIX on

    15 Symbian platform) program, the restrictions on file access that are imposed

    16 by the Symbian platform Security model. </p>

    17 <p>It shows that programs can access their own directories, but cannot, without

    18 platform security capabilities not available to ordinary programs, access

    19 the directories of other programs, or the system binary directory <filepath>sys/bin</filepath>. </p>

    20 <p>This example defines an executable file with no platform security capabilities.

    21 The program first creates its own secure directory that it can write to and

    22 read from. It then attempts to use a file in a private directory of another

    23 program, and then in <filepath>sys/bin</filepath>, and shows that these attempts

    24 are denied. </p>

    25 <section><title>Download</title> <p>Click on the following link to download

    26 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>

    27 <section><title>Description</title> <p>The following sections provide more

    28 information about the steps that the example performs. </p> <p><b> Create

    29 a secure directory</b> </p> <p>The example creates an empty secure directory

    30 for the program by using the <xref href="GUID-5EA72F64-E826-3B15-9468-902BD57F6AA7.dita"><apiname>mkdir()</apiname></xref> function. </p> <p>This

    31 empty secure directory is created in <filepath>C:\private\E80000C9</filepath>,

    32 as 0xE80000C9 is a unique identifier for the program (as specified by the

    33 third UID in its project file). </p></section>

    34 <section> <p><b>Write and read a file in the private directory </b> </p> <p>The

    35 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

    36 other file stream functions. </p> <p><b> Write and read a file in the private

    37 directory of another program </b> </p> <p>The example attempts to write and

    38 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

    39 is expected to return <codeph>NULL</codeph>, indicating that access is not

    40 possible, as the program has insufficient platform security capabilities. </p><p><b> Write

    41 and read a file in the sys/bin directory</b> </p> <p>The example attempts

    42 to write and read a file in the system's <filepath>sys/bin</filepath> directory,

    43 where program binaries are stored. </p> <p>Again, the <xref href="GUID-64886CC6-072F-3542-855A-5D733FC761E8.dita"><apiname>fopen()</apiname></xref> function

    44 is expected to return <codeph>NULL</codeph>, indicating that access is not

    45 possible, as the program has insufficient platform security capabilities. </p> </section>

    46 <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>

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

    48 platform build process</xref> describes how to build this example application. </p> <p>The

    49 example builds an executable called <filepath>fileaccessexample.exe</filepath> in

    50 the standard locations. </p> <p>To run the example, start <filepath>fileaccessexample.exe</filepath> from

    51 the file system or from your IDE. After launching the executable, depending

    52 on the emulator you are using, you may need to navigate away from the application

    53 launcher or shell screen to view the console. </p> </section>

    54 </conbody></concept>