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SYMBIAN OS V9.3

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Location: e32std.h
Link against: euser.lib

Class RSessionBase

class RSessionBase : public RHandleBase;

Description

Client-side handle to a session with a server.

This is the client-side interface through which communication with the server is channelled.

Clients normally define and implement a derived class to provide a richer interface.

Derivation

Members

Defined in RSessionBase:
CreateSession(), CreateSession(), CreateSession(), CreateSession(), CreateSession(), CreateSession(), CreateSession(), EAutoAttach, EExplicitAttach, Open(), Open(), Open(), Open(), Send(), Send(), SendReceive(), SendReceive(), SendReceive(), SendReceive(), SetReturnedHandle(), SetReturnedHandle(), SetReturnedHandle(), ShareAuto(), ShareProtected(), TAttachMode

Inherited from RHandleBase:
Attributes(), Close(), Duplicate(), FullName(), Handle(), HandleInfo(), Name(), SetHandle(), SetHandleNC(), iHandle


Member functions


ShareAuto()

inline TInt ShareAuto();

Description

Creates a session that can be shared by other threads in the current process.

After calling this function the session object may be used by threads other than than the one that created it.

Note that this can only be done with servers that mark their sessions as sharable.

Return value

TInt

KErrNone, if the session is successfully shared; KErrNoMmemory, if the attempt fails for lack of memory.

Panic codes

KERN-EXEC

23 The session cannot be shared.

See also:


ShareProtected()

inline TInt ShareProtected();

Description

Creates a session handle that can be be passed via IPC to another process as well as being shared by other threads in the current process.

After calling this function the session object may be used by threads other than than the one that created it.

Note that this can only be done with servers that mark their sessions as globally sharable.

Return value

TInt

KErrNone, if the session is successfully shared; KErrNoMmemory, if the attempt fails for lack of memory.

Panic codes

KERN-EXEC

23 The session cannot be shared.

See also:


Open()

IMPORT_C TInt Open(RMessagePtr2 aMessage, TInt aParam, TOwnerType aType=EOwnerProcess);

Description

Opens a handle to a session using a handle number sent by a client to a server.

This function is called by the server.

Parameters

RMessagePtr2 aMessage

The message pointer.

TInt aParam

An index specifying which of the four message arguments contains the handle number.

TOwnerType aType

An enumeration whose enumerators define the ownership of this session handle. If not explicitly specified, EOwnerProcess is taken as default.

Return value

TInt

KErrNone, if successful; KErrArgument, if the value of aParam is outside the range 0-3; KErrBadHandle, if not a valid handle; otherwise one of the other system-wide error codes.


Open()

IMPORT_C TInt Open(RMessagePtr2 aMessage, TInt aParam, const TSecurityPolicy &aServerPolicy, TOwnerType aType=EOwnerProcess);

Description

Opens a handle to a session using a handle number sent by a client to a server, and validate that the session's server passes a given security policy.

This function is called by the server.

Parameters

RMessagePtr2 aMessage

The message pointer.

TInt aParam

An index specifying which of the four message arguments contains the handle number.

const TSecurityPolicy &aServerPolicy

The policy to validate the session's server against.

TOwnerType aType

An enumeration whose enumerators define the ownership of this session handle. If not explicitly specified, EOwnerProcess is taken as default.

Return value

TInt

KErrNone, if successful; KErrArgument, if the value of aParam is outside the range 0-3; KErrBadHandle, if not a valid handle; KErrServerTerminating, if the session is no longer connected to a server; KErrPermissionDenied, if the session's server does not pass the given security policy; otherwise one of the other system-wide error codes.


Open()

IMPORT_C TInt Open(TInt aArgumentIndex, TOwnerType aType=EOwnerProcess);

Description

Opens a handle to a session using a handle number passed as an environment data item to the child process during the creation of that child process.

Note that this function can only be called successfully once.

Parameters

TInt aArgumentIndex

An index that identifies the slot in the process environment data that contains the handle number. This is a value relative to zero, i.e. 0 is the first item/slot. This can range from 0 to 15.

TOwnerType aType

An enumeration whose enumerators define the ownership of this session handle. If not explicitly specified, EOwnerProcess is taken as default.

Return value

TInt

KErrNone, if successful; KErrNotFound, if the slot indicated by aArgumentIndex is empty; KErrArgument, if the slot does not contain a session handle; otherwise one of the other system-wide error codes.


Open()

IMPORT_C TInt Open(TInt aArgumentIndex, const TSecurityPolicy &aServerPolicy, TOwnerType aType=EOwnerProcess);

Description

Opens a handle to a session using a handle number passed as an environment data item to the child process during the creation of that child process, after validating that the session's server passes the given security policy.

Note that this function can only be called successfully once.

Parameters

TInt aArgumentIndex

An index that identifies the slot in the process environment data that contains the handle number. This is a value relative to zero, i.e. 0 is the first item/slot. This can range from 0 to 15.

const TSecurityPolicy &aServerPolicy

The policy to validate the session's server against.

TOwnerType aType

An enumeration whose enumerators define the ownership of this session handle. If not explicitly specified, EOwnerProcess is taken as default.

Return value

TInt

KErrNone, if successful; KErrNotFound, if the slot indicated by aArgumentIndex is empty; KErrArgument, if the slot does not contain a session handle; KErrServerTerminating, if the session is no longer connected to a server; KErrPermissionDenied, if the session's server does not pass the given security policy; otherwise one of the other system-wide error codes.


SetReturnedHandle()

inline TInt SetReturnedHandle(TInt aHandleOrError);

Description

Sets the handle-number of this handle to the specified value.

The function can take a (zero or positive) handle-number, or a (negative) error number.

If aHandleOrError represents a handle-number, then the handle-number of this handle is set to that value. If aHandleOrError represents an error number, then the handle-number of this handle is set to zero and the negative value is returned.

Parameters

TInt aHandleOrError

A handle-number, if zero or positive; an error value, if negative.

Return value

TInt

KErrNone, if aHandle is a handle-number; the value of aHandleOrError, otherwise.


SetReturnedHandle()

IMPORT_C TInt SetReturnedHandle(TInt aHandleOrError, const TSecurityPolicy &aServerPolicy);

Description

Sets the handle-number of this session handle to the specified value after validating that the session's server passes a given security policy.

The function can take a (zero or positive) handle-number, or a (negative) error number.

If aHandleOrError represents a handle-number, then the handle-number of this handle is set to that value, as long as the session's server passes the security policy. If aHandleOrError represents an error number, then the handle-number of this handle is set to zero and the negative value is returned.

Parameters

TInt aHandleOrError

A handle-number, if zero or positive; an error value, if negative.

const TSecurityPolicy &aServerPolicy

The policy to validate the session's server against.

Return value

TInt

KErrNone, if aHandle is a handle-number; KErrPermissionDenied, if the session's server does not pass the security policy; the value of aHandleOrError, otherwise.


CreateSession()

protected: inline TInt CreateSession(const TDesC &aServer, const TVersion &aVersion);

Description

Creates a session with a server, specifying no message slots.

It should be called as part of session initialisation in the derived class.

Message slots are not pre-allocated for the session but are taken from a system-wide pool allowing up to 255 asynchronous messages to be outstanding. This raises a risk of failure due to lack of memory and, therefore, this mode of operation is not viable for sessions that make guarantees about the failure modes of asynchonous services.

Parameters

const TDesC &aServer

The name of the server with which a session is to be established.

const TVersion &aVersion

The lowest version of the server with which this client is compatible

Return value

TInt

KErrNone if successful, otherwise one of the other system-wide error codes.


CreateSession()

protected: IMPORT_C TInt CreateSession(const TDesC &aServer, const TVersion &aVersion, TInt aAsyncMessageSlots);

Description

Creates a session with a server.

It should be called as part of session initialisation in the derived class.

Parameters

const TDesC &aServer

The name of the server with which a session is to be established.

const TVersion &aVersion

The lowest version of the server with which this client is compatible.

TInt aAsyncMessageSlots

The number of message slots available to this session. This determines the number of outstanding requests the client may have with the server at any one time. The maximum number of slots is 255. If aAsyncMessageSlots==-1 then this indicates that the session should use messages from the global free pool of messages.

Return value

TInt

KErrNone if successful; KErrArgument, if an attempt is made to specify more than 255 message slots; otherwise one of the other system-wide error codes.


CreateSession()

protected: IMPORT_C TInt CreateSession(const TDesC &aServer, const TVersion &aVersion, TInt aAsyncMessageSlots, TIpcSessionType aType, const TSecurityPolicy *aPolicy=0, TRequestStatus *aStatus=0);

Description

Creates a session with a server.

It should be called as part of session initialisation in the derived class.

When a check fails the action taken is determined by the system wide Platform Security configuration. If PlatSecDiagnostics is ON, then a diagnostic message is emitted. If PlatSecEnforcement is OFF, then this function will return KErrNone even though the check failed.

Parameters

const TDesC &aServer

The name of the server with which a session is to be established.

const TVersion &aVersion

The lowest version of the server with which this client is compatible.

TInt aAsyncMessageSlots

The number of message slots available to this session. This determines the number of outstanding requests the client may have with the server at any one time. The maximum number of slots is 255. If aAsyncMessageSlots==-1 then this indicates that the session should use messages from the global free pool of messages.

TIpcSessionType aType

The type of session to create. See TIpcSessionType.

const TSecurityPolicy *aPolicy

A pointer to a TSecurityPolicy object. If this pointer is not 0 (zero) then the policy is applied to the process in which the server is running. If that process doesn't pass this security policy check, then the session creation will fail with the error KErrPermissionDenied. This security check allows clients to verify that the server has the expected Platform Security attributes.

TRequestStatus *aStatus

A pointer to TRequestStatus object which will be signalled when the session has been created, or in the event of an error. If aStatus==0 then session creation is done synchronously.

Return value

TInt

KErrNone if successful; KErrArgument, if an attempt is made to specify more than 255 message slots; otherwise one of the other system-wide error codes.


CreateSession()

protected: inline TInt CreateSession(RServer2 aServer, const TVersion &aVersion);

Description

Creates a session with a server, specifying no message slots.

It should be called as part of session initialisation in the derived class.

Message slots are not pre-allocated for the session but are taken from a system-wide pool allowing up to 255 asynchronous messages to be outstanding. This raises a risk of failure due to lack of memory and, therefore, this mode of operation is not viable for sessions that make guarantees about the failure modes of asynchonous services.

Parameters

RServer2 aServer

A handle to a server with which a session is to be established.

const TVersion &aVersion

The lowest version of the server with which this client is compatible

Return value

TInt

KErrNone if successful, otherwise one of the other system-wide error codes.


CreateSession()

protected: IMPORT_C TInt CreateSession(RServer2 aServer, const TVersion &aVersion, TInt aAsyncMessageSlots);

Description

Creates a session with a server.

It should be called as part of session initialisation in the derived class.

Parameters

RServer2 aServer

A handle to a server with which a session is to be established.

const TVersion &aVersion

The lowest version of the server with which this client is compatible.

TInt aAsyncMessageSlots

The number of message slots available to this session. This determines the number of outstanding requests the client may have with the server at any one time. The maximum number of slots is 255. If aAsyncMessageSlots==-1 then this indicates that the session should use messages from the global free pool of messages.

Return value

TInt

KErrNone if successful; KErrArgument, if an attempt is made to specify more than 255 message slots; otherwise one of the other system-wide error codes.


CreateSession()

protected: IMPORT_C TInt CreateSession(RServer2 aServer, const TVersion &aVersion, TInt aAsyncMessageSlots, TIpcSessionType aType, const TSecurityPolicy *aPolicy=0, TRequestStatus *aStatus=0);

Description

Creates a session with a server.

It should be called as part of session initialisation in the derived class.

When a check fails the action taken is determined by the system wide Platform Security configuration. If PlatSecDiagnostics is ON, then a diagnostic message is emitted. If PlatSecEnforcement is OFF, then this function will return KErrNone even though the check failed.

Parameters

RServer2 aServer

A handle to a server with which a session is to be established.

const TVersion &aVersion

The lowest version of the server with which this client is compatible.

TInt aAsyncMessageSlots

The number of message slots available to this session. This determines the number of outstanding requests the client may have with the server at any one time. The maximum number of slots is 255. If aAsyncMessageSlots==-1 then this indicates that the session should use messages from the global free pool of messages.

TIpcSessionType aType

The type of session to create. See TIpcSessionType.

const TSecurityPolicy *aPolicy

A pointer to a TSecurityPolicy object. If this pointer is not 0 (zero) then the policy is applied to the process in which the server is running. If that process doesn't pass this security policy check, then the session creation will fail with the error KErrPermissionDenied. This security check allows clients to verify that the server has the expected Platform Security attributes.

TRequestStatus *aStatus

A pointer to TRequestStatus object which will be signalled when the session has been created, or in the event of an error. If aStatus==0 then session creation is done synchronously.

Return value

TInt

KErrNone if successful; KErrArgument, if an attempt is made to specify more than 255 message slots; otherwise one of the other system-wide error codes.


SetReturnedHandle()

protected: static inline TInt SetReturnedHandle(TInt aHandleOrError, RHandleBase &aHandle);

Description

Parameters

TInt aHandleOrError

RHandleBase &aHandle

Return value

TInt


CreateSession()

protected: inline TInt CreateSession(const TDesC &aServer, const TVersion &aVersion, TInt aAsyncMessageSlots, TRequestStatus *aStatus);

Description

Parameters

const TDesC &aServer

const TVersion &aVersion

TInt aAsyncMessageSlots

TRequestStatus *aStatus

Return value

TInt


Send()

protected: inline TInt Send(TInt aFunction, const TIpcArgs &aArgs) const;

Description

Issues a blind request to the server with the specified function number, and arguments.

A blind request is one where the server does not issue a response to the client.

Parameters

TInt aFunction

The function number identifying the request.

const TIpcArgs &aArgs

A set of up to 4 arguments and their types to be passed to the server.

Return value

TInt

KErrNone, if the send operation is successful; KErrServerTerminated, if the server no longer present; KErrServerBusy, if there are no message slots available; KErrNoMemory, if there is insufficient memory available.

Panic codes

USER

72 if the function number is negative.


SendReceive()

protected: inline void SendReceive(TInt aFunction, const TIpcArgs &aArgs, TRequestStatus &aStatus) const;

Description

Issues an asynchronous request to the server with the specified function number and arguments.

The completion status of the request is returned via the request status object, aStatus.

Parameters

TInt aFunction

The function number identifying the request.

const TIpcArgs &aArgs

A set of up to 4 arguments and their types to be passed to the server.

TRequestStatus &aStatus

The request status object used to contain the completion status of the request.

Panic codes

USER

72 if the function number is negative.


SendReceive()

protected: inline TInt SendReceive(TInt aFunction, const TIpcArgs &aArgs) const;

Description

Issues a synchronous request to the server with the specified function number and arguments.

Parameters

TInt aFunction

The function number identifying the request.

const TIpcArgs &aArgs

A set of up to 4 arguments and their types to be passed to the server.

Return value

TInt

KErrNone, if the send operation is successful; KErrServerTerminated, if the server no longer present; KErrServerBusy, if there are no message slots available; KErrNoMemory, if there is insufficient memory available.

Panic codes

USER

72 if the function number is negative.


Send()

protected: inline TInt Send(TInt aFunction) const;

Description

Issues a blind request to the server with the specified function number, but with no arguments.

A blind request is one where the server does not issue a response to the client.

Parameters

TInt aFunction

The function number identifying the request.

Return value

TInt

KErrNone, if the send operation is successful; KErrServerTerminated, if the server no longer present; KErrServerBusy, if there are no message slots available; KErrNoMemory, if there is insufficient memory available.

Panic codes

USER

72 if the function number is negative.


SendReceive()

protected: inline void SendReceive(TInt aFunction, TRequestStatus &aStatus) const;

Description

Issues an asynchronous request to the server with the specified function number, but with no arguments.

The completion status of the request is returned via the request status object, aStatus.

Parameters

TInt aFunction

The function number identifying the request.

TRequestStatus &aStatus

The request status object used to contain the completion status of the request.

Panic codes

USER

72 if the function number is negative.


SendReceive()

protected: inline TInt SendReceive(TInt aFunction) const;

Description

Issues a synchronous request to the server with the specified function number, but with no arguments.

Parameters

TInt aFunction

The function number identifying the request.

Return value

TInt

KErrNone, if the send operation is successful; KErrServerTerminated, if the server no longer present; KErrServerBusy, if there are no message slots available; KErrNoMemory, if there is insufficient memory available.

Panic codes

USER

72 if the function number is negative.

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Member enumerations


Enum TAttachMode

TAttachMode

Description

Indicates whether or not threads in the process are automatically attached to the session when passed as a parameter to the Share() function.

EExplicitAttach

EAutoAttach