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[linux-2.6] / drivers / acpi / executer / exstorob.c
1
2 /******************************************************************************
3  *
4  * Module Name: exstorob - AML Interpreter object store support, store to object
5  *
6  *****************************************************************************/
7
8 /*
9  * Copyright (C) 2000 - 2005, R. Byron Moore
10  * All rights reserved.
11  *
12  * Redistribution and use in source and binary forms, with or without
13  * modification, are permitted provided that the following conditions
14  * are met:
15  * 1. Redistributions of source code must retain the above copyright
16  *    notice, this list of conditions, and the following disclaimer,
17  *    without modification.
18  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
19  *    substantially similar to the "NO WARRANTY" disclaimer below
20  *    ("Disclaimer") and any redistribution must be conditioned upon
21  *    including a substantially similar Disclaimer requirement for further
22  *    binary redistribution.
23  * 3. Neither the names of the above-listed copyright holders nor the names
24  *    of any contributors may be used to endorse or promote products derived
25  *    from this software without specific prior written permission.
26  *
27  * Alternatively, this software may be distributed under the terms of the
28  * GNU General Public License ("GPL") version 2 as published by the Free
29  * Software Foundation.
30  *
31  * NO WARRANTY
32  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
33  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
34  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
35  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
36  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
37  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
38  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
39  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
40  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
41  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
42  * POSSIBILITY OF SUCH DAMAGES.
43  */
44
45 #include <acpi/acpi.h>
46 #include <acpi/acinterp.h>
47
48 #define _COMPONENT          ACPI_EXECUTER
49 ACPI_MODULE_NAME("exstorob")
50
51 /*******************************************************************************
52  *
53  * FUNCTION:    acpi_ex_store_buffer_to_buffer
54  *
55  * PARAMETERS:  source_desc         - Source object to copy
56  *              target_desc         - Destination object of the copy
57  *
58  * RETURN:      Status
59  *
60  * DESCRIPTION: Copy a buffer object to another buffer object.
61  *
62  ******************************************************************************/
63 acpi_status
64 acpi_ex_store_buffer_to_buffer(union acpi_operand_object *source_desc,
65                                union acpi_operand_object *target_desc)
66 {
67         u32 length;
68         u8 *buffer;
69
70         ACPI_FUNCTION_TRACE_PTR("ex_store_buffer_to_buffer", source_desc);
71
72         /* We know that source_desc is a buffer by now */
73
74         buffer = (u8 *) source_desc->buffer.pointer;
75         length = source_desc->buffer.length;
76
77         /*
78          * If target is a buffer of length zero or is a static buffer,
79          * allocate a new buffer of the proper length
80          */
81         if ((target_desc->buffer.length == 0) ||
82             (target_desc->common.flags & AOPOBJ_STATIC_POINTER)) {
83                 target_desc->buffer.pointer = ACPI_MEM_ALLOCATE(length);
84                 if (!target_desc->buffer.pointer) {
85                         return_ACPI_STATUS(AE_NO_MEMORY);
86                 }
87
88                 target_desc->buffer.length = length;
89         }
90
91         /* Copy source buffer to target buffer */
92
93         if (length <= target_desc->buffer.length) {
94                 /* Clear existing buffer and copy in the new one */
95
96                 ACPI_MEMSET(target_desc->buffer.pointer, 0,
97                             target_desc->buffer.length);
98                 ACPI_MEMCPY(target_desc->buffer.pointer, buffer, length);
99
100 #ifdef ACPI_OBSOLETE_BEHAVIOR
101                 /*
102                  * NOTE: ACPI versions up to 3.0 specified that the buffer must be
103                  * truncated if the string is smaller than the buffer.  However, "other"
104                  * implementations of ACPI never did this and thus became the defacto
105                  * standard. ACPi 3.0_a changes this behavior such that the buffer
106                  * is no longer truncated.
107                  */
108
109                 /*
110                  * OBSOLETE BEHAVIOR:
111                  * If the original source was a string, we must truncate the buffer,
112                  * according to the ACPI spec.  Integer-to-Buffer and Buffer-to-Buffer
113                  * copy must not truncate the original buffer.
114                  */
115                 if (original_src_type == ACPI_TYPE_STRING) {
116                         /* Set the new length of the target */
117
118                         target_desc->buffer.length = length;
119                 }
120 #endif
121         } else {
122                 /* Truncate the source, copy only what will fit */
123
124                 ACPI_MEMCPY(target_desc->buffer.pointer, buffer,
125                             target_desc->buffer.length);
126
127                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
128                                   "Truncating source buffer from %X to %X\n",
129                                   length, target_desc->buffer.length));
130         }
131
132         /* Copy flags */
133
134         target_desc->buffer.flags = source_desc->buffer.flags;
135         target_desc->common.flags &= ~AOPOBJ_STATIC_POINTER;
136         return_ACPI_STATUS(AE_OK);
137 }
138
139 /*******************************************************************************
140  *
141  * FUNCTION:    acpi_ex_store_string_to_string
142  *
143  * PARAMETERS:  source_desc         - Source object to copy
144  *              target_desc         - Destination object of the copy
145  *
146  * RETURN:      Status
147  *
148  * DESCRIPTION: Copy a String object to another String object
149  *
150  ******************************************************************************/
151
152 acpi_status
153 acpi_ex_store_string_to_string(union acpi_operand_object *source_desc,
154                                union acpi_operand_object *target_desc)
155 {
156         u32 length;
157         u8 *buffer;
158
159         ACPI_FUNCTION_TRACE_PTR("ex_store_string_to_string", source_desc);
160
161         /* We know that source_desc is a string by now */
162
163         buffer = (u8 *) source_desc->string.pointer;
164         length = source_desc->string.length;
165
166         /*
167          * Replace existing string value if it will fit and the string
168          * pointer is not a static pointer (part of an ACPI table)
169          */
170         if ((length < target_desc->string.length) &&
171             (!(target_desc->common.flags & AOPOBJ_STATIC_POINTER))) {
172                 /*
173                  * String will fit in existing non-static buffer.
174                  * Clear old string and copy in the new one
175                  */
176                 ACPI_MEMSET(target_desc->string.pointer, 0,
177                             (acpi_size) target_desc->string.length + 1);
178                 ACPI_MEMCPY(target_desc->string.pointer, buffer, length);
179         } else {
180                 /*
181                  * Free the current buffer, then allocate a new buffer
182                  * large enough to hold the value
183                  */
184                 if (target_desc->string.pointer &&
185                     (!(target_desc->common.flags & AOPOBJ_STATIC_POINTER))) {
186                         /* Only free if not a pointer into the DSDT */
187
188                         ACPI_MEM_FREE(target_desc->string.pointer);
189                 }
190
191                 target_desc->string.pointer = ACPI_MEM_CALLOCATE((acpi_size)
192                                                                  length + 1);
193                 if (!target_desc->string.pointer) {
194                         return_ACPI_STATUS(AE_NO_MEMORY);
195                 }
196
197                 target_desc->common.flags &= ~AOPOBJ_STATIC_POINTER;
198                 ACPI_MEMCPY(target_desc->string.pointer, buffer, length);
199         }
200
201         /* Set the new target length */
202
203         target_desc->string.length = length;
204         return_ACPI_STATUS(AE_OK);
205 }