The QUnixSocketRights class encapsulates QUnixSocket rights data. More...

#include <qunixsocket_p.h>

Public Functions
int	dupFd () const
	Return a duplicate of the file descriptor contained in this object. More...

bool	isValid () const
	Returns true if this QUnixSocketRights instance is managing a valid file descriptor. More...

QUnixSocketRights &	operator= (const QUnixSocketRights &)
	Create a copy of other. More...

int	peekFd () const
	Returns the file descriptor contained in this object. More...

	QUnixSocketRights (int)
	Create a new QUnixSocketRights instance containing the file descriptor fd. More...

	QUnixSocketRights (const QUnixSocketRights &)
	Create a copy of other. More...

	~QUnixSocketRights ()
	Destroys the QUnixSocketRights instance. More...

Private Functions
	QUnixSocketRights (int, int)
	Construct a QUnixSocketRights instance on fd without dup(2)'ing the file descriptor. More...

Properties
QSharedDataPointer< QUnixSocketRightsPrivate >	d

Friends
class	QUnixSocket

Detailed Description

The QUnixSocketRights class encapsulates QUnixSocket rights data.

Warning: This function is not part of the public interface.; This function is not part of the public interface. :: :: ::

QUnixSocket allows you to transfer Unix file descriptors between processes. A file descriptor is referred to as "rights data" as it allows one process to transfer its right to access a resource to another.

The Unix system verifies resource permissions only when the resource is first opened. For example, consider a file on disk readable only by the user "qt". A process running as user "qt" will be able to open this file for reading. If, while the process was still reading from the file, the ownership was changed from user "qt" to user "root", the process would be allowed to continue reading from the file, even though attempting to reopen the file would be denied. Permissions are associated with special descriptors called file descriptors which are returned to a process after it initially opens a resource.

File descriptors can be duplicated within a process through the dup(2) system call. File descriptors can be passed between processes using the QUnixSocket class in the same way. Even though the receiving process never opened the resource directly, it has the same permissions to access it as the process that did.

See also: QUnixSocket

Definition at line 73 of file qunixsocket_p.h.

Constructors and Destructors

◆ QUnixSocketRights() [1/3]

QUnixSocketRights::QUnixSocketRights ( int fd )

Create a new QUnixSocketRights instance containing the file descriptor fd.

fd will be dup(2)'d internally, so the application is free to close fd following this call.

If the dup(2) fails, or you pass an invalid fd, an QUnixSocketRights::isValid(){invalid } object will be constructed.

QUnixSocketRights instances are immutable and the internal file descriptor will be shared between any copies made of this object. The system will close(2) the file descriptor once it is no longer needed.

Definition at line 163 of file qunixsocket.cpp.

 {
     d = new QUnixSocketRightsPrivate();
     if(-1 == fd) {
         d->fd = -1;
     } else {
         d->fd = qt_safe_dup(fd);
 #ifdef QUNIXSOCKET_DEBUG
         if(-1 == d->fd) {
             qDebug() << "QUnixSocketRights: Unable to duplicate fd "
                      << fd << " (" << ::strerror(errno) << ')';
         }
 #endif
     }
 }

◆ ~QUnixSocketRights()

QUnixSocketRights::~QUnixSocketRights ( )

Destroys the QUnixSocketRights instance.

Definition at line 198 of file qunixsocket.cpp.

199 {

200 }

◆ QUnixSocketRights() [2/3]

QUnixSocketRights::QUnixSocketRights ( const QUnixSocketRights & other )

Create a copy of other.

Definition at line 215 of file qunixsocket.cpp.

 : d(other.d)
 {
 }

◆ QUnixSocketRights() [3/3]

QUnixSocketRights::QUnixSocketRights	(	int	fd,
		int
	)

private

Construct a QUnixSocketRights instance on fd without dup(2)'ing the file descriptor.

Warning: This function is not part of the public interface.

Definition at line 188 of file qunixsocket.cpp.

 {
     Q_ASSERT(-1 != fd);
     d = new QUnixSocketRightsPrivate();
     d->fd = fd;
 }

Functions

◆ dupFd()

int QUnixSocketRights::dupFd ( ) const

Return a duplicate of the file descriptor contained in this object.

If this is an QUnixSocketRights::isValid(){invalid } object, or the dup(2) call fails, an invalid file descriptor (-1) will be returned.

See also: QUnixSocketRights::peekFd()

Definition at line 238 of file qunixsocket.cpp.

 {
     if(-1 == d->fd) return -1;
 
     int rv = qt_safe_dup(d->fd);
 
 #ifdef QUNIXSOCKET_DEBUG
     if(-1 == rv)
         qDebug() << "QUnixSocketRights: Unable to duplicate managed file "
                     "descriptor (" << ::strerror(errno) << ')';
 #endif
 
     return rv;
 }

◆ isValid()

bool QUnixSocketRights::isValid ( ) const

Returns true if this QUnixSocketRights instance is managing a valid file descriptor.

This method is equivalent to (-1 != peekFd()).

See also: QUnixSocketRights::peekFd()

Definition at line 226 of file qunixsocket.cpp.

Referenced by QUnixSocketPrivate::writeActivated().

 {
     return d->fd != -1;
 }

◆ operator=()

QUnixSocketRights & QUnixSocketRights::operator= ( const QUnixSocketRights & other )

Create a copy of other.

Definition at line 206 of file qunixsocket.cpp.

 {
     d = other.d;
     return *this;
 }

◆ peekFd()

int QUnixSocketRights::peekFd ( ) const

Returns the file descriptor contained in this object.

If this is an QUnixSocketRights::isValid(){invalid } object an invalid file descriptor (-1) will be returned.

The lifetime of this file descriptor is tied to the lifetime of the QUnixSocketRights instance. The file descriptor returned by this method may be close(2)'d when the QUnixSocketRights instance is destroyed. If you want to continue to use the file descriptor use QUnixSocketRights::dupFd() instead.