freecon, freeconary - free memory associated with SELinux security contexts
getpeercon - get security context of a peer socket
int getcon(char **context);
int getcon_raw(char **context);
int getprevcon(char **context);
int getprevcon_raw(char **context);
int getpidcon(pid_t pid, char **context);
int getpidcon_raw(pid_t pid, char **context);
int getpeercon(int fd, char **context);
int getpeercon_raw(int fd, char **context);
void freecon(char *con);
void freeconary(char **con);
int setcon(char *context);
getprevcon() same as getcon but gets the context before the last exec.
getpidcon() returns the process context for the specified PID.
getpeercon() retrieves context of peer socket, and set *context to refer to it, which must be free'd with freecon().
freecon() frees the memory allocated for a security context.
freeconary() frees the memory allocated for a context array.
If con is NULL, no operation is performed.
setcon() sets the current security context of the process to a new value. Note that use of this function requires that the entire application be trusted to maintain any desired separation between the old and new security contexts, unlike exec-based transitions performed via setexeccon(3). When possible, decompose your application and use setexeccon(3) and execve(3) instead.
Since access to file descriptors is revalidated upon use by SELinux, the new context must be explicitly authorized in the policy to use the descriptors opened by the old context if that is desired. Otherwise, attempts by the process to use any existing descriptors (including stdin, stdout, and stderr) after performing the setcon() will fail.
A multi-threaded application can perform a setcon() prior to creating any child threads, in which case all of the child threads will inherit the new context. However, prior to Linux 2.6.28, setcon() would fail if there are any other threads running in the same process since this would yield an inconsistency among the security contexts of threads sharing the same memory space. Since Linux 2.6.28, setcon() is permitted for threads within a multi-threaded process if the new security context is bounded by the old security context, where the bounded relation is defined through typebounds statements in the policy and guarantees that the new security context has a subset of the permissions of the old security context.
If the process was being ptraced at the time of the setcon() operation, ptrace permission will be revalidated against the new context and the setcon() will fail if it is not allowed by policy.