David Caabeiro's Forum Nokia Blog

ARM RVCT 4.0 for Symbian Foundation available for free

david.caabeiro — Wed, 21 Oct 2009 18:23:29 +0200

Today looks like an interesting day for Symbian programmers. Right after announcing EKA2 kernel availability as open source, the Symbian Foundation has published details for downloading a free version (some restrictions apply) of the ARM RVCT.

For details, check out this page

ARound: LBS + sensors

david.caabeiro — Sat, 13 Dec 2008 16:19:42 +0100

Recently I had the chance to play a bit with the new Sensor FW API, made publicly available few weeks ago. It's no secret that such functionality will certainly bring new possibilities and offers to the s60 ecosystem. One such example is mixing the live video stream from your camera with tags (provided by the user or some other external resource), thus providing extended information to the physical world.

Of course the field of augmented/mixed reality is not new, but current devices are starting to make this reasonable, with no need of backpacks head-mounted displays or add-on gadgets (though walking around while facing your screen might look a bit weird as well)

The most obvious use case is making use of these placemarks when doing tourism. You tap on a specific point of interest and you get detailed information (either text or audio) about that place.

Unfortunately I don't have a decent camera to make a proper video capture, so here are some screen captures taken on a weekend short walk, featuring the application with a basic UI. (Those attending the MWC will find the place familiar..)

WDF / 3GSM (P.I.P.S.)

PushL — Tue, 13 Feb 2007 19:16:18 +0100

Among the several talks in the Symbian WDF, I was quite interested in the one on PIPS. The presentation (by Erik Jacobson from Symbian) turned out to be pretty interesting and enlightening. Having worked in some porting projects in the past, and suffering many of the shortcomings of the estlib (now soon to be deprecated), there seems to be at last some good news for future porting developing.

Here're some highlights:

- select() is supported: this single addition makes the whole project worth to me :)
- exec() / fork() are not supported, as they would require many changes in the kernel (use posix_spawn() instead)
- Many IPC mechanisms supported: pipes, fifos, etc.
- Signals and thus asynchronous I/O is not supported
- dlsym() cannot be used with symbolic names, use ordinals instead (there could be some facility provided in the future though, to ease development)
- Carbide.c++ v1.2 is intended to support PIPS development (v9.3+ will introduce new target types: STDEXE & STDDLL). Anyway you can always rely on the good old command line.

PIPS was originally intended for v9.3, but given that most functionality works in v9.1, there will be a sis available to that OS version.
To prove its effectiveness, an independent company ported the TightVNC client for both S60 and UIQ.

To start to get a feeling out of it, I'd recommend you keep an eye on the P.I.P.S. Home @ DevNet , starting with the freely downloadable booklet.

Writing secure servers with CPolicyServer

PushL — Mon, 05 Feb 2007 02:59:24 +0100

Symbian v9 introduces new features, one of the most notable being PlatSec. Even though the SDK docs provide good information about related APIs, I haven't seen any sample code illustrating its use.

The main purpose of a server is providing ordered access to a shared resource. In pre-9 releases, this was achieved by means of CServer/CSession ("Symbian OS Explained" provides an excellent overview about this topic). For controlling access to your server, V9 provides a policy framework which is built on top of the newer CServer2 class (for a thorough discussion about this topic, I recommend getting a copy of "Symbian OS Platform Security")

The following snippet shows the necessary changes to add to a sample server (A full working example is provided)

// Security policy
const TUint KServerPolicyRangeCount = 2;

const TInt KServerPolicyRanges[KServerPolicyRangeCount] =
{
    0,              // range is 0 inclusive
    EMaxService     // range is 1-KMaxTInt inclusive
};

const TUint8 KServerPolicyElementsIndex[KServerPolicyRangeCount] =
{
    0,                              // applies to 0th range
    CPolicyServer::ENotSupported    // applies to 1st range
};

const CPolicyServer::TPolicyElement KServerPolicyElements[] =
{
    { _INIT_SECURITY_POLICY_V0(0x7FFFFFFF), CPolicyServer::EFailClient }
};

const CPolicyServer::TPolicy KServerPolicy =
{
    CPolicyServer::EAlwaysPass, // specifies all connect attempts should pass
    KServerPolicyRangeCount,
    KServerPolicyRanges,
    KServerPolicyElementsIndex,
    KServerPolicyElements
};

The CPolicyServer constructor gets a policy table among its arguments, which represents the server policies:

CSimpleServer::CSimpleServer() :
    CPolicyServer(EPriorityStandard, KServerPolicy, ESharableSessions)
{}

In this example case, we're dealing with just one function. The KServerPolicyRanges elements represent the ranges of function numbers (obtained by RMessage2::Function() ) to be searched for. The index obtained is used in KServerPolicyElementsIndex to determine the policy to be applied (which is specified in the KServerPolicyElements array)

So when a message is received with function number 0, the framework determines that it corresponds to the first entry of the ranges array, which determines the policy to use (in this case the check of a specific vendor id). In case of failure, the message is completed with KErrPermissionDenied. Other requests containing a different function number will return KErrNotSupported (as specified by the ENotSupported item in the policy array)

Download source code

Other recommended reading: Transient Server Template