selinux_status_open - Online Linux Manual PageSection : 3
Updated : 22 January 2011
Source : kaigai@ak.jp.nec.com
Note : SELinux API documentation

NAMEselinux_status_open, selinux_status_close, selinux_status_updated, selinux_status_getenforce, selinux_status_policyload and selinux_status_deny_unknown − reference the SELinux kernel status without invocation of system calls

SYNOPSIS#include <selinux/avc.h> int selinux_status_open(int fallback); void selinux_status_close(void); int selinux_status_updated(void); int selinux_status_getenforce(void); int selinux_status_policyload(void); int selinux_status_deny_unknown(void);

DESCRIPTIONLinux 2.6.37 or later provides a SELinux kernel status page; being mostly placed on /sys/fs/selinux/status entry. It enables userspace applications to mmap this page with read-only mode, then it informs some status without system call invocations. In some cases that a userspace application tries to apply heavy frequent access control; such as row-level security in databases, it will face unignorable cost to communicate with kernel space to check invalidation of userspace avc. These functions provides applications a way to know some kernel events without system-call invocation or worker thread for monitoring. selinux_status_open() tries to open(2) /sys/fs/selinux/status and mmap(2) it in read-only mode. The file-descriptor and pointer to the page shall be stored internally; Don't touch them directly. Set 1 on the fallback argument to handle a case of older kernels without kernel status page support. In this case, this function tries to open a netlink socket using avc_netlink_open(3) and overwrite corresponding callbacks (setenforce and policyload). Thus, we need to pay attention to the interaction with these interfaces, when fallback mode is enabled. selinux_status_close() unmap the kernel status page and close its file descriptor, or close the netlink socket if fallbacked. selinux_status_updated() processes status update events. There are two kinds of status updates. setenforce events will change the effective enforcing state used within the AVC, and policyload events will result in a cache flush. This function returns 0 if there have been no updates since the last call, 1 if there have been updates since the last call, or −1 on error. selinux_status_getenforce() returns 0 if SELinux is running in permissive mode, 1 if enforcing mode, or −1 on error. Same as security_getenforce(3) except with or without system call invocation. selinux_status_policyload() returns times of policy reloaded on the running system, or −1 on error. Note that it is not a reliable value on fallback-mode until it receive the first event message via netlink socket. Thus, don't use this value to know actual times of policy reloaded. selinux_status_deny_unknown() returns 0 if SELinux treats policy queries on undefined object classes or permissions as being allowed, 1 if such queries are denied, or −1 on error. Also note that these interfaces are not thread-safe, so you have to protect them from concurrent calls using exclusive locks when multiple threads are performing.

RETURN VALUEselinux_status_open() returns 0 or 1 on success. 1 means we are ready to use these interfaces, but netlink socket was opened as fallback instead of the kernel status page. On error, −1 shall be returned. Any other functions with a return value shall return its characteristic value as described above, or −1 on errors.

SEE ALSOmmap(2), avc_netlink_open(3), security_getenforce(3), security_deny_unknown(3)
0
Johanes Gumabo
Data Size   :   8,439 byte
man-selinux_status_open.3Build   :   2024-12-05, 20:55   :  
Visitor Screen   :   x
Visitor Counter ( page / site )   :   4 / 180,288
Visitor ID   :     :  
Visitor IP   :   52.14.49.59   :  
Visitor Provider   :   AMAZON-02   :  
Provider Position ( lat x lon )   :   39.962500 x -83.006100   :   x
Provider Accuracy Radius ( km )   :   1000   :  
Provider City   :   Columbus   :  
Provider Province   :   Ohio ,   :   ,
Provider Country   :   United States   :  
Provider Continent   :   North America   :  
Visitor Recorder   :   Version   :  
Visitor Recorder   :   Library   :  
Online Linux Manual Page   :   Version   :   Online Linux Manual Page - Fedora.40 - march=x86-64 - mtune=generic - 24.12.05
Online Linux Manual Page   :   Library   :   lib_c - 24.10.03 - march=x86-64 - mtune=generic - Fedora.40
Online Linux Manual Page   :   Library   :   lib_m - 24.10.03 - march=x86-64 - mtune=generic - Fedora.40
Data Base   :   Version   :   Online Linux Manual Page Database - 24.04.13 - march=x86-64 - mtune=generic - fedora-38
Data Base   :   Library   :   lib_c - 23.02.07 - march=x86-64 - mtune=generic - fedora.36

Very long time ago, I have the best tutor, Wenzel Svojanovsky . If someone knows the email address of Wenzel Svojanovsky , please send an email to johanes_gumabo@yahoo.co.id .
If error, please print screen and send to johanes_gumabo@yahoo.co.id
Under development. Support me via PayPal.