avc_context_to_sid(3)     SELinux API documentation    avc_context_to_sid(3)

NAME         top

       avc_context_to_sid,  avc_sid_to_context, avc_get_initial_sid - obtain
       and manipulate SELinux security ID's

SYNOPSIS         top

       #include <selinux/selinux.h>
       #include <selinux/avc.h>

       int avc_context_to_sid(char *ctx, security_id_t *sid);

       int avc_sid_to_context(security_id_t sid, char **ctx);

       int avc_get_initial_sid(const char *name, security_id_t *sid);

DESCRIPTION         top

       Security ID's (SID's) are opaque representations of security
       contexts, managed by the userspace AVC.

       avc_context_to_sid() returns a SID for the given context in the
       memory referenced by sid.

       avc_sid_to_context() returns a copy of the context represented by sid
       in the memory referenced by ctx.  The user must free the copy with

       avc_get_initial_sid() returns a SID for the kernel initial security
       identifier specified by name.

RETURN VALUE         top

       avc_context_to_sid() and avc_sid_to_context() return zero on success.
       On error, -1 is returned and errno is set appropriately.

ERRORS         top

       ENOMEM An attempt to allocate memory failed.

NOTES         top

       As of libselinux version 2.0.86, SID's are no longer reference
       counted.  A SID will be valid from the time it is first obtained
       until the next call to avc_destroy(3).  The sidget(3) and sidput(3)
       functions, formerly used to adjust the reference count, are no-ops
       and are deprecated.

AUTHOR         top

       Eamon Walsh <>

SEE ALSO         top

       avc_init(3), avc_has_perm(3), avc_cache_stats(3),
       avc_add_callback(3), getcon(3), freecon(3), selinux(8)

COLOPHON         top

       This page is part of the selinux (Security-Enhanced Linux user-space
       libraries and tools) project.  Information about the project can be
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       have a bug report for this manual page, see 
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                                 27 May 2004           avc_context_to_sid(3)