File +Access Example: Accessing the File System Using P.I.P.S.

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.

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 sys/bin.

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 sys/bin, and shows that these attempts +are denied.

Download

Click +on the following link to download the example: FileAccessExample.zip

Click: browse to view the example code.

Description

The +following sections provide more information about the steps that the example +performs.

Create a secure directory

The example creates +an empty secure directory for the program by using the mkdir() function.

This +empty secure directory is created in C:\private\E80000C9, +as 0xE80000C9 is a unique identifier for the program (as specified by the +third UID in its project file).

Write and read +a file in the private directory

The example writes and reads +a file in the secure directory using the fopen() and other +file stream functions.

Write and read a file in the private directory +of another program

The example attempts to write and read a file +in the secure directory of another program.

The fopen() function +is expected to return NULL, indicating that access is not +possible, as the program has insufficient platform security capabilities.

Write +and read a file in the sys/bin directory

The example attempts +to write and read a file in the system's sys/bin directory, +where program binaries are stored.

Again, the fopen() function +is expected to return NULL, indicating that access is not +possible, as the program has insufficient platform security capabilities.

Related APIs

mkdir()

fopen()

Build

The Symbian build process describes +how to build this example application.

The example builds an executable +called fileaccessexample.exe in the standard locations.

To +run the example, start fileaccessexample.exe 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.