This is xnu-11215.1.10. See this file in:
#include <sys/cdefs.h>
#include <sys/proc_internal.h>
#include <sys/vnode_internal.h>
#include <sys/ubc_internal.h>
#include <sys/file_internal.h>
#include <sys/vnode.h>
// From vm_parameter_validation_kern.c
void testprintf(const char *format, ...);
struct file_control_return {
void * control;
struct fileproc * fp;
struct vnode * vp;
int fd;
};
struct file_control_return get_control_from_fd(int fd);
struct file_control_return
get_control_from_fd(int fd)
{
struct fileproc *fp = NULL;
struct vnode *vp = NULL;
size_t file_size;
off_t fs;
memory_object_control_t file_control = NULL;
int error;
struct file_control_return ret = {NULL, NULL, NULL, fd};
proc_t p = current_proc();
/* get file structure from file descriptor */
error = fp_get_ftype(p, fd, DTYPE_VNODE, EINVAL, &fp);
if (error) {
testprintf("%s: [%d(%s)]: fp_get_ftype() failed, error %d\n",
__func__, proc_getpid(p), p->p_comm, error);
return ret;
}
ret.fp = fp;
/* We need at least read permission on the file */
if (!(fp->fp_glob->fg_flag & FREAD)) {
testprintf("%s: [%d(%s)]: not readable\n",
__func__, proc_getpid(p), p->p_comm);
return ret;
}
/* Get the vnode from file structure */
vp = (struct vnode *)fp_get_data(fp);
error = vnode_getwithref(vp);
if (error) {
testprintf("%s: [%d(%s)]: failed to get vnode, error %d\n",
__func__, proc_getpid(p), p->p_comm, error);
return ret;
}
ret.vp = vp;
/* Make sure the vnode is a regular file */
if (vp->v_type != VREG) {
testprintf("%s: [%d(%s)]: vnode not VREG\n",
__func__, proc_getpid(p), p->p_comm);
return ret;
}
/* get vnode size */
error = vnode_size(vp, &fs, vfs_context_current());
if (error) {
return ret;
}
file_size = fs;
/* get the file's memory object handle */
file_control = ubc_getobject(vp, UBC_HOLDOBJECT);
if (file_control == MEMORY_OBJECT_CONTROL_NULL) {
testprintf("%s: [%d(%s)]: no memory object\n",
__func__, proc_getpid(p), p->p_comm);
return ret;
}
ret.control = file_control;
return ret;
}
void cleanup_control_related_data(struct file_control_return info);
void
cleanup_control_related_data(struct file_control_return info)
{
if (info.fp != NULL) {
/* release the file descriptor */
fp_drop(current_proc(), info.fd, info.fp, 0);
}
if (info.vp != NULL) {
(void)vnode_put(info.vp);
}
}