1 /*
2 * Server-side semaphore management
3 *
4 * Copyright (C) 1998 Alexandre Julliard
5 *
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * This library is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with this library; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
19 */
20
21 #include "config.h"
22 #include "wine/port.h"
23
24 #include <assert.h>
25 #include <stdio.h>
26 #include <stdlib.h>
27 #include <stdarg.h>
28
29 #include "ntstatus.h"
30 #define WIN32_NO_STATUS
31 #include "windef.h"
32 #include "winternl.h"
33
34 #include "handle.h"
35 #include "thread.h"
36 #include "request.h"
37 #include "security.h"
38
39 struct semaphore
40 {
41 struct object obj; /* object header */
42 unsigned int count; /* current count */
43 unsigned int max; /* maximum possible count */
44 };
45
46 static void semaphore_dump( struct object *obj, int verbose );
47 static struct object_type *semaphore_get_type( struct object *obj );
48 static int semaphore_signaled( struct object *obj, struct thread *thread );
49 static int semaphore_satisfied( struct object *obj, struct thread *thread );
50 static unsigned int semaphore_map_access( struct object *obj, unsigned int access );
51 static int semaphore_signal( struct object *obj, unsigned int access );
52
53 static const struct object_ops semaphore_ops =
54 {
55 sizeof(struct semaphore), /* size */
56 semaphore_dump, /* dump */
57 semaphore_get_type, /* get_type */
58 add_queue, /* add_queue */
59 remove_queue, /* remove_queue */
60 semaphore_signaled, /* signaled */
61 semaphore_satisfied, /* satisfied */
62 semaphore_signal, /* signal */
63 no_get_fd, /* get_fd */
64 semaphore_map_access, /* map_access */
65 default_get_sd, /* get_sd */
66 default_set_sd, /* set_sd */
67 no_lookup_name, /* lookup_name */
68 no_open_file, /* open_file */
69 no_close_handle, /* close_handle */
70 no_destroy /* destroy */
71 };
72
73
74 static struct semaphore *create_semaphore( struct directory *root, const struct unicode_str *name,
75 unsigned int attr, unsigned int initial, unsigned int max,
76 const struct security_descriptor *sd )
77 {
78 struct semaphore *sem;
79
80 if (!max || (initial > max))
81 {
82 set_error( STATUS_INVALID_PARAMETER );
83 return NULL;
84 }
85 if ((sem = create_named_object_dir( root, name, attr, &semaphore_ops )))
86 {
87 if (get_error() != STATUS_OBJECT_NAME_EXISTS)
88 {
89 /* initialize it if it didn't already exist */
90 sem->count = initial;
91 sem->max = max;
92 if (sd) default_set_sd( &sem->obj, sd, OWNER_SECURITY_INFORMATION|
93 GROUP_SECURITY_INFORMATION|
94 DACL_SECURITY_INFORMATION|
95 SACL_SECURITY_INFORMATION );
96 }
97 }
98 return sem;
99 }
100
101 static int release_semaphore( struct semaphore *sem, unsigned int count,
102 unsigned int *prev )
103 {
104 if (prev) *prev = sem->count;
105 if (sem->count + count < sem->count || sem->count + count > sem->max)
106 {
107 set_error( STATUS_SEMAPHORE_LIMIT_EXCEEDED );
108 return 0;
109 }
110 else if (sem->count)
111 {
112 /* there cannot be any thread to wake up if the count is != 0 */
113 sem->count += count;
114 }
115 else
116 {
117 sem->count = count;
118 wake_up( &sem->obj, count );
119 }
120 return 1;
121 }
122
123 static void semaphore_dump( struct object *obj, int verbose )
124 {
125 struct semaphore *sem = (struct semaphore *)obj;
126 assert( obj->ops == &semaphore_ops );
127 fprintf( stderr, "Semaphore count=%d max=%d ", sem->count, sem->max );
128 dump_object_name( &sem->obj );
129 fputc( '\n', stderr );
130 }
131
132 static struct object_type *semaphore_get_type( struct object *obj )
133 {
134 static const WCHAR name[] = {'S','e','m','a','p','h','o','r','e'};
135 static const struct unicode_str str = { name, sizeof(name) };
136 return get_object_type( &str );
137 }
138
139 static int semaphore_signaled( struct object *obj, struct thread *thread )
140 {
141 struct semaphore *sem = (struct semaphore *)obj;
142 assert( obj->ops == &semaphore_ops );
143 return (sem->count > 0);
144 }
145
146 static int semaphore_satisfied( struct object *obj, struct thread *thread )
147 {
148 struct semaphore *sem = (struct semaphore *)obj;
149 assert( obj->ops == &semaphore_ops );
150 assert( sem->count );
151 sem->count--;
152 return 0; /* not abandoned */
153 }
154
155 static unsigned int semaphore_map_access( struct object *obj, unsigned int access )
156 {
157 if (access & GENERIC_READ) access |= STANDARD_RIGHTS_READ | SYNCHRONIZE;
158 if (access & GENERIC_WRITE) access |= STANDARD_RIGHTS_WRITE | SEMAPHORE_MODIFY_STATE;
159 if (access & GENERIC_EXECUTE) access |= STANDARD_RIGHTS_EXECUTE;
160 if (access & GENERIC_ALL) access |= STANDARD_RIGHTS_ALL | SEMAPHORE_ALL_ACCESS;
161 return access & ~(GENERIC_READ | GENERIC_WRITE | GENERIC_EXECUTE | GENERIC_ALL);
162 }
163
164 static int semaphore_signal( struct object *obj, unsigned int access )
165 {
166 struct semaphore *sem = (struct semaphore *)obj;
167 assert( obj->ops == &semaphore_ops );
168
169 if (!(access & SEMAPHORE_MODIFY_STATE))
170 {
171 set_error( STATUS_ACCESS_DENIED );
172 return 0;
173 }
174 return release_semaphore( sem, 1, NULL );
175 }
176
177 /* create a semaphore */
178 DECL_HANDLER(create_semaphore)
179 {
180 struct semaphore *sem;
181 struct unicode_str name;
182 struct directory *root = NULL;
183 const struct object_attributes *objattr = get_req_data();
184 const struct security_descriptor *sd;
185
186 reply->handle = 0;
187
188 if (!objattr_is_valid( objattr, get_req_data_size() ))
189 return;
190
191 sd = objattr->sd_len ? (const struct security_descriptor *)(objattr + 1) : NULL;
192 objattr_get_name( objattr, &name );
193
194 if (objattr->rootdir && !(root = get_directory_obj( current->process, objattr->rootdir, 0 )))
195 return;
196
197 if ((sem = create_semaphore( root, &name, req->attributes, req->initial, req->max, sd )))
198 {
199 if (get_error() == STATUS_OBJECT_NAME_EXISTS)
200 reply->handle = alloc_handle( current->process, sem, req->access, req->attributes );
201 else
202 reply->handle = alloc_handle_no_access_check( current->process, sem, req->access, req->attributes );
203 release_object( sem );
204 }
205
206 if (root) release_object( root );
207 }
208
209 /* open a handle to a semaphore */
210 DECL_HANDLER(open_semaphore)
211 {
212 struct unicode_str name;
213 struct directory *root = NULL;
214 struct semaphore *sem;
215
216 get_req_unicode_str( &name );
217 if (req->rootdir && !(root = get_directory_obj( current->process, req->rootdir, 0 )))
218 return;
219
220 if ((sem = open_object_dir( root, &name, req->attributes, &semaphore_ops )))
221 {
222 reply->handle = alloc_handle( current->process, &sem->obj, req->access, req->attributes );
223 release_object( sem );
224 }
225
226 if (root) release_object( root );
227 }
228
229 /* release a semaphore */
230 DECL_HANDLER(release_semaphore)
231 {
232 struct semaphore *sem;
233
234 if ((sem = (struct semaphore *)get_handle_obj( current->process, req->handle,
235 SEMAPHORE_MODIFY_STATE, &semaphore_ops )))
236 {
237 release_semaphore( sem, req->count, &reply->prev_count );
238 release_object( sem );
239 }
240 }
241
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