| .\" Hey Emacs! This file is -*- nroff -*- source. |
| .\" |
| .\" Author: Eamon Walsh (ewalsh@tycho.nsa.gov) 2004 |
| .TH "avc_context_to_sid" "3" "27 May 2004" "" "SELinux API documentation" |
| .SH "NAME" |
| avc_context_to_sid, avc_sid_to_context, sidput, sidget, avc_get_initial_sid \- obtain and manipulate SELinux security ID's. |
| .SH "SYNOPSIS" |
| .B #include <selinux/selinux.h> |
| |
| .B #include <selinux/avc.h> |
| .sp |
| .BI "int avc_context_to_sid(security_context_t " ctx ", security_id_t *" sid ");" |
| .sp |
| .BI "int avc_sid_to_context(security_id_t " sid ", security_context_t *" ctx ");" |
| .sp |
| .BI "int sidget(security_id_t " sid ");" |
| .sp |
| .BI "int sidput(security_id_t " sid ");" |
| .sp |
| .BI "int avc_get_initial_sid(const char *" name ", security_id_t *" sid ");" |
| .sp |
| .SH "DESCRIPTION" |
| Security ID's (SID's) are reference-counted, opaque representations of security contexts. |
| |
| .B avc_context_to_sid |
| returns a SID for the given |
| .I context |
| in the memory referenced by |
| .IR sid , |
| incrementing its reference count by 1. |
| |
| .B avc_sid_to_context |
| returns a copy of the context represented by |
| .I sid |
| in the memory referenced by |
| .IR ctx . |
| The user must free the copy with |
| .BR freecon (3). |
| |
| .B sidget |
| increments the reference count of |
| .I sid |
| by 1. |
| |
| .B sidput |
| decrements the reference count of |
| .I sid |
| by 1. If the count ever reaches zero, the SID becomes |
| invalid and must not be used any further. |
| |
| .B avc_get_initial_sid |
| returns a SID for the kernel initial security identifier specified by |
| .I name |
| |
| .SH "RETURN VALUE" |
| .B sidget |
| and |
| .B sidput |
| return the new reference count. A return value of zero indicates |
| an invalid SID. |
| |
| .B avc_context_to_sid |
| and |
| .B avc_sid_to_context |
| return zero on success. On error, \-1 is returned and |
| .I errno |
| is set appropriately. |
| |
| .SH "ERRORS" |
| .TP |
| .B EINVAL |
| The provided |
| .I sid |
| has a zero reference count and is invalid. |
| .TP |
| .B ENOMEM |
| An attempt to allocate memory failed. |
| |
| .SH "NOTES" |
| The expected usage pattern for these functions is that |
| .B avc_context_to_sid |
| will be called once to obtain a SID for a newly created object, |
| .B sidget |
| will be called on a SID when its object is duplicated, and |
| .B sidput |
| will be called on a SID when its object is destroyed. Proper reference counting is necessary to ensure that SID's and associated cache entries are reclaimed from memory when no longer needed. |
| |
| .SH "AUTHOR" |
| Eamon Walsh <ewalsh@tycho.nsa.gov> |
| |
| .SH "SEE ALSO" |
| .BR avc_init (3), |
| .BR avc_has_perm (3), |
| .BR avc_cache_stats (3), |
| .BR avc_add_callback (3), |
| .BR getcon (3), |
| .BR freecon (3) |
| .BR selinux (8) |
