sidput(3)

1avc_context_to_sid(3)     SE Linux API documentation     avc_context_to_sid(3)
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NAME

6       avc_context_to_sid,  avc_sid_to_context,  sidput,  sidget, avc_get_ini‐
7       tial_sid - obtain and manipulate SELinux security ID's.
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SYNOPSIS

10       #include <selinux/selinux.h>
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12       #include <selinux/avc.h>
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14       int avc_context_to_sid(security_context_t ctx, security_id_t *sid);
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16       int avc_sid_to_context(security_id_t sid, security_context_t *ctx);
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18       int sidget(security_id_t sid);
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20       int sidput(security_id_t sid);
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22       int avc_get_initial_sid(const char *name, security_id_t *sid);
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DESCRIPTION

26       Security ID's (SID's) are reference-counted, opaque representations  of
27       security contexts.
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29       avc_context_to_sid  returns  a  SID for the given context in the memory
30       referenced by sid, incrementing its reference count by 1.
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32       avc_sid_to_context returns a copy of the context represented by sid  in
33       the  memory  referenced  by  ctx.   The  user  must  free the copy with
34       freecon(3).
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36       sidget increments the reference count of sid by 1.
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38       sidput decrements the reference count of sid by 1.  If the  count  ever
39       reaches zero, the SID becomes invalid and must not be used any further.
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41       avc_get_initial_sid returns a SID for the kernel initial security iden‐
42       tifier specified by name
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RETURN VALUE

46       sidget and sidput return the new reference count.  A  return  value  of
47       zero indicates an invalid SID.
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49       avc_context_to_sid  and  avc_sid_to_context return zero on success.  On
50       error, -1 is returned and errno is set appropriately.
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ERRORS

54       EINVAL The provided sid has a zero reference count and is invalid.
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56       ENOMEM An attempt to allocate memory failed.
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NOTES

60       The expected  usage  pattern  for  these  functions  is  that  avc_con‐
61       text_to_sid  will  be  called  once to obtain a SID for a newly created
62       object, sidget will be called on a SID when its object  is  duplicated,
63       and  sidput  will  be  called  on  a  SID when its object is destroyed.
64       Proper reference counting is necessary to ensure that SID's and associ‐
65       ated cache entries are reclaimed from memory when no longer needed.
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AUTHOR

69       Eamon Walsh <ewalsh@epoch.ncsc.mil>
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