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114 lines
3.2 KiB
Groff
114 lines
3.2 KiB
Groff
.TH L4_CAPABILITY_CONTROL 7 2009-11-07 "Codezero" "Codezero Programmer's Manual"
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.SH NAME
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.nf
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.BR "l4_capability_control" " - Capability inspection and manipulation"
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.SH SYNOPSIS
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.nf
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.B #include <l4lib/arch/syscalls.h>
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.B #include <l4lib/arch/syslib.h>
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.BI "int l4_capability_control (unsigned int " "req" ", unsigned int " "flags",
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.BI " l4id_t " "capid" ", l4id_t " "tid" ", void " "*buf" ");"
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.SH DESCRIPTION
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.BR l4_capability_control() " - "
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enables a thread to read and manipulate the list of capabilities that it possesses. Capabilities may be shared, granted to other threads, or they may be replicated, destroyed, reduced in privileges or split into parts, effectively enabling a dynamically configurable resource management architecture. The thread calling this system call must possess relevant capabilities as any operation done by this call are also subject to capability checking.
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.TP
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.fi
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.I req
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denotes the type of request. See below for a full list.
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.TP
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.fi
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.I flags
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denotes additional flags for the given request. See below for a list of flags.
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.TP
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.fi
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.I buf
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almost always contains a capability structure that describes the request with regard to given
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.IR "req"
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and
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.IR "flags."
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.TP
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.BR CAP_CONTROL_NCAPS
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Get capability count, sum of private capabilities, address space capabilities and container capabilities.
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.TP
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.BR CAP_CONTROL_READ
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Returns a
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.BI "struct " "capability"
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via
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.I buf.
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.TP
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.BR CAP_CONTROL_SHARE
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If
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.B CAP_SHARE_SINGLE
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is specified in
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.IR "flag",
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only the capability is moved from container capability list to address space capablity list, if
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.B CAP_SHARE_ALL
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is specified in
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.IR "flag",
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all capabiliteis are moved from container's capability list to address sapce capability list.
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.TP
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.BR CAP_CONTROL_GRANT
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Grant the capabilities in the buffer
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.IR "buf",
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if
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.I flag
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has
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.BR "CAP_GRANT_SINGLE",
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if
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.B CAP_GRANT_ALL
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is provided with flag all capabilities are granted, if
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.B CAP_GRANT_IMMUTABLE
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is specified in flags then all(or one) capabilities are made immutable.
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.TP
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.BR CAP_CONTROL_REPLICATE
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Replicates an existing capability. This is for expanding capabilities to managed children.
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.TP
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.B CAP_CONTROL_SPLIT
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Capabilities are split by diff'ing resources possessed between capabilities.
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.I flags
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may be one of
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.B CAP_SPLIT_SIZE
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,
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.B CAP_SPLIT_ACCESS
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or
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.B CAP_SPLIT_RANGE.
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.TP
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.BR CAP_CONTROL_DEDUCE
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Deduction can be by access permissions, start, end, size fields, or the target resource type. Inter-container deduction is not allowed. Target resource deduction denotes reducing the applicable space of the target, e.g. from a container to a space in that container.
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.TP
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.BR CAP_CONTROL_DESTROY
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Destroys a capability specified in
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.IR "flag".
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.TP
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.I capid
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Currently not used, for Future
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.TP
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.I tid
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Currently not used, for Future
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.TP
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.I buf
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pointer to buffer, which holds more information depending on
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.IR "req".
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.SH RETURN VALUE
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.IR "l4_capability_control"()
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Returns 0 on success, and negetive error value on failure. See below for errors
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.SH ERRORS
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.TP
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.B EINVAL
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when a capability struct is passed in
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.IR "buf"
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but has some invalid fields.
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.TP
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.B ENOCAP
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when capabilities required don't exist or do not have sufficient privileges.
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.SH SEE ALSO
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.BR "capability"(7)
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