L4Re::Random Struct Reference

Low-bandwidth interface for random number generators. More...

#include <random>

Inheritance diagram for L4Re::Random:

Collaboration diagram for L4Re::Random:

Public Member Functions
long	get_random (l4_size_t size, L4::Ipc::Array< char, unsigned long > *buffer)
	Get a random number.
Public Member Functions inherited from L4::Icu
l4_msgtag_t	bind (unsigned irqnum, L4::Cap< Triggerable > irq, l4_utcb_t *utcb=l4_utcb()) noexcept
	Bind an interrupt line of an interrupt controller to an interrupt object.
l4_msgtag_t	unbind (unsigned irqnum, L4::Cap< Triggerable > irq, l4_utcb_t *utcb=l4_utcb()) noexcept
	Remove binding of an interrupt line from the interrupt controller object.
l4_msgtag_t	info (l4_icu_info_t *info, l4_utcb_t *utcb=l4_utcb()) noexcept
	Get information about the ICU features.
l4_msgtag_t	msi_info (l4_umword_t irqnum, l4_uint64_t source, l4_icu_msi_info_t *msi_info)
	Get MSI info about IRQ.
l4_msgtag_t	mask (unsigned irqnum, l4_umword_t *label=0, l4_timeout_t to=L4_IPC_NEVER, l4_utcb_t *utcb=l4_utcb()) noexcept
	Mask an IRQ line.
l4_msgtag_t	set_mode (unsigned irqnum, l4_umword_t mode, l4_utcb_t *utcb=l4_utcb()) noexcept
	Set interrupt mode.
Public Member Functions inherited from L4::Irq_eoi
l4_msgtag_t	unmask (unsigned irqnum, l4_umword_t *label=0, l4_timeout_t to=L4_IPC_NEVER, l4_utcb_t *utcb=l4_utcb()) noexcept
	Unmask the given interrupt line.

Additional Inherited Members
Protected Types inherited from L4::Kobject_t< Random, L4::Icu >
typedef Random	Class
	The target interface type (inheriting from Kobject_t)
typedef Typeid::Iface< PROTO_ANY, Random >	__Iface
	The interface description for the derived class.
typedef Typeid::Merge_list< Typeid::Iface_list< __Iface >, typename Base::__Iface_list >	__Iface_list
	The list of all RPC interfaces provided directly or through inheritance.
Protected Types inherited from L4::Kobject_t< Icu, Irq_eoi, L4_PROTO_IRQ, Type_info::Demand_t< 1 > >
typedef Icu	Class
	The target interface type (inheriting from Kobject_t)
typedef Typeid::Iface< PROTO, Icu >	__Iface
	The interface description for the derived class.
typedef Typeid::Merge_list< Typeid::Iface_list< __Iface >, typename Base::__Iface_list >	__Iface_list
	The list of all RPC interfaces provided directly or through inheritance.
Protected Member Functions inherited from L4::Kobject_t< Random, L4::Icu >
L4::Cap< Class >	c () const noexcept
	Get the capability to ourselves.
Protected Member Functions inherited from L4::Kobject_t< Icu, Irq_eoi, L4_PROTO_IRQ, Type_info::Demand_t< 1 > >
L4::Cap< Class >	c () const noexcept
	Get the capability to ourselves.
Static Protected Member Functions inherited from L4::Kobject_t< Random, L4::Icu >
static void	__check_protocols__ () noexcept
	Helper to check for protocol conflicts.
Static Protected Member Functions inherited from L4::Kobject_t< Icu, Irq_eoi, L4_PROTO_IRQ, Type_info::Demand_t< 1 > >
static void	__check_protocols__ () noexcept
	Helper to check for protocol conflicts.

Detailed Description

Low-bandwidth interface for random number generators.

The interface offers an ICU interface where a client can register an interrupt to get notified when entropy is available. Support for notifications is optional. If a service does not implement notification, it must return 0 for the number of interrupts in the info() call. The notification interrupt must have index 0.

Include File

#include <l4/re/random> 

Definition at line 33 of file random.

Member Function Documentation

get_random()

long L4Re::Random::get_random	(	l4_size_t	size,
		L4::Ipc::Array< char, unsigned long > *	buffer
	)

Get a random number.

Parameters

	size	Number of bytes of entropy requested.
[out]	buffer	Buffer containing the random number. Each byte in the buffer contains 8 bits of randomness.

Return values

>=0	Actual size of the returned random number in bytes. This may be less than the requested size. The return value may also be 0 if temporarily no entropy is available.
-L4_EIO	Source of randomness permanently unavailable.
<0	IPC error.

This function should never block. It should immediately return as much entropy as is available. If the call returns less than the requested bytes and a notification interrupt was installed, then the service triggers an interrupt as soon as the remaining entropy is available. That means that when an interrupt is triggered, the service must guarantee that the next call to get_random() returns at least the number of missing bytes for the call that initially triggered the notification.

If get_random() is called while a notification is pending, then the behaviour is implementation-defined.

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The documentation for this struct was generated from the following file:

• l4/re/random