osfmk/kern/ipc_misc.c

   1 /*
   2  * Copyright (c) 2008 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 #include <mach/mach_types.h>
  29 #include <mach/notify.h>
  30 #include <ipc/ipc_port.h>
  31 #include <kern/ipc_kobject.h>
  32 #include <kern/ipc_misc.h>
  33
  34 extern void fileport_releasefg(struct fileglob *);
  35
  36 /*
  37  * fileport_alloc
  38  *
  39  * Description: Obtain a send right for the given fileglob, which must be
  40  *              referenced.
  41  *
  42  * Parameters:  fg              A fileglob.
  43  *
  44  * Returns:     Port of type IKOT_FILEPORT with fileglob set as its kobject.
  45  *              Port is returned with a send right.
  46  */
  47 ipc_port_t
  48 fileport_alloc(struct fileglob *fg)
  49 {
  50         ipc_port_t fileport;
  51         ipc_port_t sendport;
  52         ipc_port_t notifyport;
  53
  54         fileport = ipc_port_alloc_kernel();
  55         if (fileport == IP_NULL) {
  56                 goto out;
  57         }
  58
  59         ipc_kobject_set(fileport, (ipc_kobject_t)fg, IKOT_FILEPORT);
  60         notifyport = ipc_port_make_sonce(fileport);
  61         ip_lock(fileport); /* unlocked by ipc_port_nsrequest */
  62         ipc_port_nsrequest(fileport, 1, notifyport, &notifyport);
  63
  64         sendport = ipc_port_make_send(fileport);
  65         if (!IP_VALID(sendport)) {
  66                 panic("Couldn't allocate send right for fileport!\n");
  67         }
  68
  69 out:
  70         return fileport;
  71 }
  72
  73
  74 /*
  75  * fileport_get_fileglob
  76  *
  77  * Description: Obtain the fileglob associated with a given port.
  78  *
  79  * Parameters: port             A Mach port of type IKOT_FILEPORT.
  80  *
  81  * Returns:    NULL             The given Mach port did not reference a
  82  *                              fileglob.
  83  *             !NULL            The fileglob that is associated with the
  84  *                              Mach port.
  85  *
  86  * Notes: The caller must have a reference on the fileport.
  87  */
  88 struct fileglob *
  89 fileport_port_to_fileglob(ipc_port_t port)
  90 {
  91         struct fileglob *fg = NULL;
  92
  93         if (!IP_VALID(port))
  94                 return NULL;
  95
  96         ip_lock(port);
  97         if (ip_active(port) && IKOT_FILEPORT == ip_kotype(port))
  98                 fg = (void *)port->ip_kobject;
  99         ip_unlock(port);
 100
 101         return fg;
 102 }
 103
 104
 105 /*
 106  * fileport_notify
 107  *
 108  * Description: Handle a no-senders notification for a fileport.  Unless
 109  *              the message is spoofed, destroys the port and releases
 110  *              its reference on the fileglob.
 111  *
 112  * Parameters: msg              A Mach no-senders notification message.
 113  */
 114 void
 115 fileport_notify(mach_msg_header_t *msg)
 116 {
 117         mach_no_senders_notification_t *notification = (void *)msg;
 118         ipc_port_t port = notification->not_header.msgh_remote_port;
 119         struct fileglob *fg = NULL;
 120
 121         if (!IP_VALID(port))
 122                 panic("Invalid port passed to fileport_notify()\n");
 123
 124         ip_lock(port);
 125
 126         fg = (struct fileglob *)port->ip_kobject;
 127
 128         if (!ip_active(port))
 129                 panic("Inactive port passed to fileport_notify()\n");
 130         if (ip_kotype(port) != IKOT_FILEPORT)
 131                 panic("Port of type other than IKOT_FILEPORT passed to fileport_notify()\n");
 132         if (fg == NULL)
 133                 panic("fileport without an assocated fileglob\n");
 134
 135         if (port->ip_srights == 0) {
 136                 ip_unlock(port);
 137
 138                 fileport_releasefg(fg);
 139                 ipc_port_dealloc_kernel(port);
 140         } else {
 141                 ip_unlock(port);
 142         }
 143
 144         return;
 145 }