xnu-1504.3.12.tar.gz

[apple/xnu.git] / osfmk / ipc / ipc_kmsg.c

diff --git a/osfmk/ipc/ipc_kmsg.c b/osfmk/ipc/ipc_kmsg.c
index 9adfe5b832f90296e4b60148459a118620099a51..d61a26a7705ce22352459fe48c7fb5c3f552011f 100644 (file)
--- a/osfmk/ipc/ipc_kmsg.c
+++ b/osfmk/ipc/ipc_kmsg.c
@@ -595,7 +595,7 @@ ipc_kmsg_alloc(
                mach_msg_size_t max_desc = (mach_msg_size_t)(((size - sizeof(mach_msg_base_t)) /
                                           sizeof(mach_msg_ool_descriptor32_t)) *
                                           DESC_SIZE_ADJUSTMENT);
-               if (msg_and_trailer_size >= MACH_MSG_SIZE_MAX - max_desc)
+               if (msg_and_trailer_size > MACH_MSG_SIZE_MAX - max_desc)
                        return IKM_NULL;
 
                max_expanded_size = msg_and_trailer_size + max_desc;
@@ -617,12 +617,9 @@ ipc_kmsg_alloc(
                        assert(i <= IKM_STASH);
                        kmsg = cache->entries[--i];
                        cache->avail = i;
-                       ikm_check_init(kmsg, max_expanded_size);
                        enable_preemption();
-                       kmsg->ikm_header = (mach_msg_header_t *)
-                                          ((vm_offset_t)(kmsg + 1) +
-                                           max_expanded_size -
-                                           msg_and_trailer_size);
+                       ikm_check_init(kmsg, max_expanded_size);
+                       ikm_set_header(kmsg, msg_and_trailer_size);
                        return (kmsg);
                }
                enable_preemption();
@@ -633,10 +630,7 @@ ipc_kmsg_alloc(
 
        if (kmsg != IKM_NULL) {
                ikm_init(kmsg, max_expanded_size);
-               kmsg->ikm_header = (mach_msg_header_t *)
-                                  ((vm_offset_t)(kmsg + 1) +
-                                   max_expanded_size -
-                                   msg_and_trailer_size);
+               ikm_set_header(kmsg, msg_and_trailer_size);
        }
 
        return(kmsg);
@@ -1072,6 +1066,23 @@ ipc_kmsg_clear_prealloc(
        IP_CLEAR_PREALLOC(port, kmsg);
 }
 
+/*
+ *     Routine:        ipc_kmsg_prealloc
+ *     Purpose:
+ *             Wraper to ipc_kmsg_alloc() to account for
+ *             header expansion requirements.
+ */
+ipc_kmsg_t
+ipc_kmsg_prealloc(mach_msg_size_t size)
+{
+#if defined(__LP64__)
+       if (size > MACH_MSG_SIZE_MAX - LEGACY_HEADER_SIZE_DELTA)
+               return IKM_NULL;
+
+       size += LEGACY_HEADER_SIZE_DELTA;
+#endif
+       return ipc_kmsg_alloc(size);
+}
 
 
 /*
@@ -1243,10 +1254,9 @@ ipc_kmsg_get_from_kernel(
         * clients.  These are set up for those kernel clients
         * which cannot afford to wait.
         */
-#ifndef __LP64__
-       /* LP64todo - does the prealloc kmsg need ikm_header padding?
-        */
        if (IP_PREALLOC(dest_port)) {
+               mach_msg_size_t max_desc = 0;
+
                ip_lock(dest_port);
                if (!ip_active(dest_port)) {
                        ip_unlock(dest_port);
@@ -1254,19 +1264,26 @@ ipc_kmsg_get_from_kernel(
                }
                assert(IP_PREALLOC(dest_port));
                kmsg = dest_port->ip_premsg;
-               if (msg_and_trailer_size > kmsg->ikm_size) {
-                       ip_unlock(dest_port);
-                       return MACH_SEND_TOO_LARGE;
-               }
                if (ikm_prealloc_inuse(kmsg)) {
                        ip_unlock(dest_port);
                        return MACH_SEND_NO_BUFFER;
                }
+#if !defined(__LP64__)
+               if (msg->msgh_bits & MACH_MSGH_BITS_COMPLEX) {
+                       assert(size > sizeof(mach_msg_base_t));
+                       max_desc = ((mach_msg_base_t *)msg)->body.msgh_descriptor_count *
+                               DESC_SIZE_ADJUSTMENT;
+               }
+#endif
+               if (msg_and_trailer_size > kmsg->ikm_size - max_desc) {
+                       ip_unlock(dest_port);
+                       return MACH_SEND_TOO_LARGE;
+               }
                ikm_prealloc_set_inuse(kmsg, dest_port);
+               ikm_set_header(kmsg, msg_and_trailer_size);
                ip_unlock(dest_port);
        }
        else
-#endif /* !__LP64__ */
        {
                kmsg = ipc_kmsg_alloc(msg_and_trailer_size);
                if (kmsg == IKM_NULL)