G::Root Class Reference

A class which acquires the process's special privileges on construction and releases them on destruction. More...

#include <groot.h>

Public Member Functions
	Root ()
	Default constructor. More...
	Root (bool change_group)
	Constructor overload with explicit control over whether to change the group-id or not. More...
	~Root ()
	Desctructor. More...

Static Public Member Functions
static void	init (const std::string &non_root, bool default_change_group=true)
	Initialises this class on process start-up by releasing root (or suid) privileges. More...
static Identity	nobody ()
	Returns the 'nobody' identity corresponding to the init() user name. More...
static Identity	start (SignalSafe)
	A signal-safe alternative to construction.
static void	stop (SignalSafe, Identity)
	A signal-safe alternative to destruction.

Detailed Description

A class which acquires the process's special privileges on construction and releases them on destruction.

Despite the name of the class the special privileges are not necessarily root privileges; they can be suid privileges.

The class must be initialised by calling a static init() method. If instances are nested then the inner instances have no effect.

The effect of this class depends on whether the process's real-id is root or not. If the real-id is root then the effective-id is switched to some named 'ordinary' user's id at startup, and then back to what it was (ie. root or the suid id) for the critical sections. Otherwise, the effective-id is switched to the real-id at startup and switched back to what it was for the critical sections.

The implementation uses G::Process and G::Identity.

Definition at line 49 of file groot.h.

Constructor & Destructor Documentation

G::Root::Root

(

)

Default constructor.

Acquires special privileges by switching the user-id and possibly the group-id (see init()).

Does nothing if the class has not been initialised by a call to init(). Does nothing if there is another instance at an outer scope.

The implementation uses G::Process::beSpecial().

Definition at line 34 of file groot.cpp.

G::Root::Root ( bool  change_group )

explicit

Constructor overload with explicit control over whether to change the group-id or not.

Definition at line 47 of file groot.cpp.

G::Root::~Root

(

)

Desctructor.

Releases special privileges if this instance acquired them.

The implementation uses G::Process::beOrdinary().

Definition at line 60 of file groot.cpp.

Member Function Documentation

void G::Root::init ( const std::string &  non_root, bool  default_change_group = true  )

static

Initialises this class on process start-up by releasing root (or suid) privileges.

The string parameter gives a non-privileged username which is used if the real user-id is root.

The group-id behaviour of the default constructor is modified by the boolean parameter.

Definition at line 92 of file groot.cpp.

G::Identity G::Root::nobody ( )

static

Returns the 'nobody' identity corresponding to the init() user name.

Precondition: init() called

Definition at line 102 of file groot.cpp.

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The documentation for this class was generated from the following files:

• /home/graeme/videotools/src/glib/groot.h
• /home/graeme/videotools/src/glib/groot.cpp