text: #include <unistd.h>
  #include <sys/types.h>
  #include <fcntl.h>
  #include <stdlib.h>
  #include <stdio.h>
  #include <errno.h>
  #include <string.h>
  #include <limits.h>
  #include "selinux_internal.h"
  #include "policy.h"
  #include "mapping.h"
  
  int security_validatetrans_raw(const char *scon,
  			       const char *tcon,
  			       security_class_t tclass,
  			       const char *newcon)
  {
  	char path[PATH_MAX];
  	char *buf = NULL;
  	int size, bufsz;
  	int fd, ret = -1;
  	errno = ENOENT;
  
  	if (!selinux_mnt) {
  		return -1;
  	}
  
  	snprintf(path, sizeof path, "%s/validatetrans", selinux_mnt);
  	fd = open(path, O_WRONLY | O_CLOEXEC);
  	if (fd < 0) {
  		return -1;
  	}
  
  	errno = EINVAL;
  	size = selinux_page_size;
  	buf = malloc(size);
  	if (!buf) {
  		goto out;
  	}
  
  	bufsz = snprintf(buf, size, "%s %s %hu %s", scon, tcon, unmap_class(tclass), newcon);
  	if (bufsz >= size || bufsz < 0) {
  		// It got truncated or there was an encoding error
  		goto out;
  	}
  
  	// clear errno for write()
  	errno = 0;
  	ret = write(fd, buf, strlen(buf));
  	if (ret > 0) {
  		// The kernel returns the bytes written on success, not 0 as noted in the commit message
  		ret = 0;
  	}
  out:
  	free(buf);
  	close(fd);
  	return ret;
  }
  
  
  int security_validatetrans(const char *scon,
  			   const char *tcon,
  			   security_class_t tclass,
  			   const char *newcon)
  {
  	int ret = -1;
  	char *rscon = NULL;
  	char *rtcon = NULL;
  	char *rnewcon = NULL;
  
  	if (selinux_trans_to_raw_context(scon, &rscon)) {
  		goto out;
  	}
  
  	if (selinux_trans_to_raw_context(tcon, &rtcon)) {
  		goto out;
  	}
  
  	if (selinux_trans_to_raw_context(newcon, &rnewcon)) {
  		goto out;
  	}
  
  	ret = security_validatetrans_raw(rscon, rtcon, tclass, rnewcon);
  
  out:
  	freecon(rnewcon);
  	freecon(rtcon);
  	freecon(rscon);
  
  	return ret;
  }
  
  