libselinux/src/policyvers.c

#include <unistd.h>
#include <sys/types.h>
#include <fcntl.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include "selinux_internal.h"
#include <stdio.h>
#include "policy.h"
#include "dso.h"
#include <limits.h>

int security_policyvers(void)
{
	int fd, ret;
	char path[PATH_MAX];
	char buf[20];
	unsigned vers = DEFAULT_POLICY_VERSION;

	if (!selinux_mnt) {
		errno = ENOENT;
		return -1;
	}

	snprintf(path, sizeof path, "%s/policyvers", selinux_mnt);
	fd = open(path, O_RDONLY | O_CLOEXEC);
	if (fd < 0) {
		if (errno == ENOENT)
			return vers;
		else
			return -1;
	}
	memset(buf, 0, sizeof buf);
	ret = read(fd, buf, sizeof buf - 1);
	close(fd);
	if (ret < 0)
		return -1;

	if (sscanf(buf, "%u", &vers) != 1)
		return -1;

	return vers;
}

hidden_def(security_policyvers)