xnu-7195.101.1.tar.gz

[apple/xnu.git] / osfmk / kern / ipc_misc.c

/*
 * Copyright (c) 2008, 2010 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 *
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 *
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 *
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */
#include <mach/mach_types.h>
#include <mach/notify.h>
#include <ipc/ipc_port.h>
#include <kern/ipc_kobject.h>
#include <kern/ipc_misc.h>

#include <mach/mach_port.h>
#include <mach/vm_map.h>
#include <vm/vm_map.h>
#include <vm/vm_kern.h>

extern void fileport_releasefg(struct fileglob *);

/*
 * fileport_alloc
 *
 * Description: Obtain a send right for the given fileglob, which must be
 *		referenced.
 *
 * Parameters:  fg		A fileglob.
 *
 * Returns:     Port of type IKOT_FILEPORT with fileglob set as its kobject.
 *              Port is returned with a send right.
 */
ipc_port_t
fileport_alloc(struct fileglob *fg)
{
	return ipc_kobject_alloc_port((ipc_kobject_t)fg, IKOT_FILEPORT,
	           IPC_KOBJECT_ALLOC_MAKE_SEND | IPC_KOBJECT_ALLOC_NSREQUEST);
}


/*
 * fileport_get_fileglob
 *
 * Description: Obtain the fileglob associated with a given port.
 *
 * Parameters: port		A Mach port of type IKOT_FILEPORT.
 *
 * Returns:    NULL		The given Mach port did not reference a
 *				fileglob.
 *	       !NULL		The fileglob that is associated with the
 *				Mach port.
 *
 * Notes: The caller must have a reference on the fileport.
 */
struct fileglob *
fileport_port_to_fileglob(ipc_port_t port)
{
	struct fileglob *fg = NULL;

	if (!IP_VALID(port)) {
		return NULL;
	}

	ip_lock(port);
	if (ip_active(port) && IKOT_FILEPORT == ip_kotype(port)) {
		fg = (void *) ip_get_kobject(port);
	}
	ip_unlock(port);

	return fg;
}


/*
 * fileport_notify
 *
 * Description: Handle a no-senders notification for a fileport.  Unless
 *              the message is spoofed, destroys the port and releases
 *              its reference on the fileglob.
 *
 * Parameters: msg		A Mach no-senders notification message.
 */
void
fileport_notify(mach_msg_header_t *msg)
{
	mach_no_senders_notification_t *notification = (void *)msg;
	ipc_port_t port = notification->not_header.msgh_remote_port;
	struct fileglob *fg = NULL;

	if (!IP_VALID(port)) {
		panic("Invalid port passed to fileport_notify()\n");
	}

	ip_lock(port);

	fg = (struct fileglob *) ip_get_kobject(port);

	if (!ip_active(port)) {
		panic("Inactive port passed to fileport_notify()\n");
	}
	if (ip_kotype(port) != IKOT_FILEPORT) {
		panic("Port of type other than IKOT_FILEPORT passed to fileport_notify()\n");
	}
	if (fg == NULL) {
		panic("fileport without an assocated fileglob\n");
	}

	if (port->ip_srights == 0) {
		ip_unlock(port);

		fileport_releasefg(fg);
		ipc_port_dealloc_kernel(port);
	} else {
		ip_unlock(port);
	}
}

/*
 * fileport_invoke
 *
 * Description: Invoke a function with the fileglob underlying the fileport.
 *		Returns the error code related to the fileglob lookup.
 *
 * Parameters:	task		The target task
 *		action		The function to invoke with the fileglob
 *		arg		Anonymous pointer to caller state
 *		rval		The value returned from calling 'action'
 */
kern_return_t
fileport_invoke(task_t task, mach_port_name_t name,
    int (*action)(mach_port_name_t, struct fileglob *, void *),
    void *arg, int *rval)
{
	kern_return_t kr;
	ipc_port_t fileport;
	struct fileglob *fg;

	kr = ipc_object_copyin(task->itk_space, name,
	    MACH_MSG_TYPE_COPY_SEND, (ipc_object_t *)&fileport, 0, NULL,
	    IPC_OBJECT_COPYIN_FLAGS_ALLOW_IMMOVABLE_SEND);
	if (kr != KERN_SUCCESS) {
		return kr;
	}

	if ((fg = fileport_port_to_fileglob(fileport)) != NULL) {
		*rval = (*action)(name, fg, arg);
	} else {
		kr = KERN_FAILURE;
	}
	ipc_port_release_send(fileport);
	return kr;
}

/*
 * fileport_walk
 *
 * Description: Invoke the action function on every fileport in the task.
 *
 *		This could be more efficient if we refactored mach_port_names()
 *		so that (a) it didn't compute the type information unless asked
 *		and (b) it could be asked to -not- unwire/copyout the memory
 *		and (c) if we could ask for port names by kobject type. Not
 *		clear that it's worth all that complexity, though.
 *
 * Parameters:  task		The target task
 *		action		The function to invoke on each fileport
 *		arg		Anonymous pointer to caller state.
 */
kern_return_t
fileport_walk(task_t task,
    int (*action)(mach_port_name_t, struct fileglob *, void *arg),
    void *arg)
{
	mach_port_name_t *names;
	mach_msg_type_number_t ncnt, tcnt;
	vm_map_copy_t map_copy_names, map_copy_types;
	vm_map_address_t map_names;
	kern_return_t kr;
	uint_t i;
	int rval;

	/*
	 * mach_port_names returns the 'name' and 'types' in copied-in
	 * form.  Discard 'types' immediately, then copyout 'names'
	 * back into the kernel before walking the array.
	 */

	kr = mach_port_names(task->itk_space,
	    (mach_port_name_t **)&map_copy_names, &ncnt,
	    (mach_port_type_t **)&map_copy_types, &tcnt);
	if (kr != KERN_SUCCESS) {
		return kr;
	}

	vm_map_copy_discard(map_copy_types);

	kr = vm_map_copyout(ipc_kernel_map, &map_names, map_copy_names);
	if (kr != KERN_SUCCESS) {
		vm_map_copy_discard(map_copy_names);
		return kr;
	}
	names = (mach_port_name_t *)(uintptr_t)map_names;

	for (rval = 0, i = 0; i < ncnt; i++) {
		if (fileport_invoke(task, names[i], action, arg,
		    &rval) == KERN_SUCCESS && -1 == rval) {
			break;          /* early termination clause */
		}
	}
	vm_deallocate(ipc_kernel_map,
	    (vm_address_t)names, ncnt * sizeof(*names));
	return KERN_SUCCESS;
}