247 lines
8.1 KiB
C
247 lines
8.1 KiB
C
/*
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* Server-side semaphore management
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*
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* Copyright (C) 1998 Alexandre Julliard
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
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*/
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#include "config.h"
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#include "wine/port.h"
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#include <assert.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <stdarg.h>
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#include "ntstatus.h"
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#define WIN32_NO_STATUS
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#include "windef.h"
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#include "winternl.h"
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#include "handle.h"
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#include "thread.h"
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#include "request.h"
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#include "security.h"
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struct semaphore
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{
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struct object obj; /* object header */
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unsigned int count; /* current count */
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unsigned int max; /* maximum possible count */
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};
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static void semaphore_dump( struct object *obj, int verbose );
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static struct object_type *semaphore_get_type( struct object *obj );
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static int semaphore_signaled( struct object *obj, struct wait_queue_entry *entry );
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static void semaphore_satisfied( struct object *obj, struct wait_queue_entry *entry );
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static unsigned int semaphore_map_access( struct object *obj, unsigned int access );
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static int semaphore_signal( struct object *obj, unsigned int access );
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static const struct object_ops semaphore_ops =
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{
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sizeof(struct semaphore), /* size */
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semaphore_dump, /* dump */
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semaphore_get_type, /* get_type */
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add_queue, /* add_queue */
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remove_queue, /* remove_queue */
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semaphore_signaled, /* signaled */
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semaphore_satisfied, /* satisfied */
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semaphore_signal, /* signal */
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no_get_fd, /* get_fd */
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semaphore_map_access, /* map_access */
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default_get_sd, /* get_sd */
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default_set_sd, /* set_sd */
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no_lookup_name, /* lookup_name */
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no_open_file, /* open_file */
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no_close_handle, /* close_handle */
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no_destroy /* destroy */
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};
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static struct semaphore *create_semaphore( struct directory *root, const struct unicode_str *name,
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unsigned int attr, unsigned int initial, unsigned int max,
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const struct security_descriptor *sd )
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{
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struct semaphore *sem;
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if (!max || (initial > max))
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{
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set_error( STATUS_INVALID_PARAMETER );
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return NULL;
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}
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if ((sem = create_named_object_dir( root, name, attr, &semaphore_ops )))
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{
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if (get_error() != STATUS_OBJECT_NAME_EXISTS)
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{
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/* initialize it if it didn't already exist */
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sem->count = initial;
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sem->max = max;
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if (sd) default_set_sd( &sem->obj, sd, OWNER_SECURITY_INFORMATION|
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GROUP_SECURITY_INFORMATION|
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DACL_SECURITY_INFORMATION|
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SACL_SECURITY_INFORMATION );
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}
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}
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return sem;
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}
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static int release_semaphore( struct semaphore *sem, unsigned int count,
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unsigned int *prev )
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{
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if (prev) *prev = sem->count;
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if (sem->count + count < sem->count || sem->count + count > sem->max)
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{
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set_error( STATUS_SEMAPHORE_LIMIT_EXCEEDED );
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return 0;
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}
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else if (sem->count)
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{
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/* there cannot be any thread to wake up if the count is != 0 */
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sem->count += count;
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}
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else
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{
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sem->count = count;
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wake_up( &sem->obj, count );
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}
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return 1;
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}
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static void semaphore_dump( struct object *obj, int verbose )
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{
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struct semaphore *sem = (struct semaphore *)obj;
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assert( obj->ops == &semaphore_ops );
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fprintf( stderr, "Semaphore count=%d max=%d\n", sem->count, sem->max );
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}
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static struct object_type *semaphore_get_type( struct object *obj )
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{
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static const WCHAR name[] = {'S','e','m','a','p','h','o','r','e'};
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static const struct unicode_str str = { name, sizeof(name) };
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return get_object_type( &str );
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}
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static int semaphore_signaled( struct object *obj, struct wait_queue_entry *entry )
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{
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struct semaphore *sem = (struct semaphore *)obj;
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assert( obj->ops == &semaphore_ops );
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return (sem->count > 0);
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}
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static void semaphore_satisfied( struct object *obj, struct wait_queue_entry *entry )
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{
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struct semaphore *sem = (struct semaphore *)obj;
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assert( obj->ops == &semaphore_ops );
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assert( sem->count );
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sem->count--;
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}
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static unsigned int semaphore_map_access( struct object *obj, unsigned int access )
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{
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if (access & GENERIC_READ) access |= STANDARD_RIGHTS_READ | SEMAPHORE_QUERY_STATE;
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if (access & GENERIC_WRITE) access |= STANDARD_RIGHTS_WRITE | SEMAPHORE_MODIFY_STATE;
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if (access & GENERIC_EXECUTE) access |= STANDARD_RIGHTS_EXECUTE | SYNCHRONIZE;
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if (access & GENERIC_ALL) access |= STANDARD_RIGHTS_ALL | SEMAPHORE_ALL_ACCESS;
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return access & ~(GENERIC_READ | GENERIC_WRITE | GENERIC_EXECUTE | GENERIC_ALL);
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}
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static int semaphore_signal( struct object *obj, unsigned int access )
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{
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struct semaphore *sem = (struct semaphore *)obj;
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assert( obj->ops == &semaphore_ops );
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if (!(access & SEMAPHORE_MODIFY_STATE))
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{
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set_error( STATUS_ACCESS_DENIED );
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return 0;
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}
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return release_semaphore( sem, 1, NULL );
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}
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/* create a semaphore */
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DECL_HANDLER(create_semaphore)
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{
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struct semaphore *sem;
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struct unicode_str name;
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struct directory *root = NULL;
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const struct security_descriptor *sd;
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const struct object_attributes *objattr = get_req_object_attributes( &sd, &name );
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if (!objattr) return;
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if (objattr->rootdir && !(root = get_directory_obj( current->process, objattr->rootdir, 0 )))
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return;
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if ((sem = create_semaphore( root, &name, objattr->attributes, req->initial, req->max, sd )))
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{
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if (get_error() == STATUS_OBJECT_NAME_EXISTS)
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reply->handle = alloc_handle( current->process, sem, req->access, objattr->attributes );
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else
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reply->handle = alloc_handle_no_access_check( current->process, sem,
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req->access, objattr->attributes );
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release_object( sem );
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}
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if (root) release_object( root );
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}
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/* open a handle to a semaphore */
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DECL_HANDLER(open_semaphore)
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{
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struct unicode_str name;
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struct directory *root = NULL;
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struct semaphore *sem;
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get_req_unicode_str( &name );
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if (req->rootdir && !(root = get_directory_obj( current->process, req->rootdir, 0 )))
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return;
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if ((sem = open_object_dir( root, &name, req->attributes, &semaphore_ops )))
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{
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reply->handle = alloc_handle( current->process, &sem->obj, req->access, req->attributes );
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release_object( sem );
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}
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if (root) release_object( root );
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}
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/* release a semaphore */
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DECL_HANDLER(release_semaphore)
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{
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struct semaphore *sem;
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if ((sem = (struct semaphore *)get_handle_obj( current->process, req->handle,
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SEMAPHORE_MODIFY_STATE, &semaphore_ops )))
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{
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release_semaphore( sem, req->count, &reply->prev_count );
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release_object( sem );
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}
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}
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/* query details about the semaphore */
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DECL_HANDLER(query_semaphore)
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{
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struct semaphore *sem;
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if ((sem = (struct semaphore *)get_handle_obj( current->process, req->handle,
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SEMAPHORE_QUERY_STATE, &semaphore_ops )))
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{
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reply->current = sem->count;
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reply->max = sem->max;
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release_object( sem );
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}
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}
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