1// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
2/******************************************************************************
3 *
4 * Module Name: exstorob - AML object store support, store to object
5 *
6 * Copyright (C) 2000 - 2025, Intel Corp.
7 *
8 *****************************************************************************/
9
10#include <acpi/acpi.h>
11#include "accommon.h"
12#include "acinterp.h"
13
14#define _COMPONENT ACPI_EXECUTER
15ACPI_MODULE_NAME("exstorob")
16
17/*******************************************************************************
18 *
19 * FUNCTION: acpi_ex_store_buffer_to_buffer
20 *
21 * PARAMETERS: source_desc - Source object to copy
22 * target_desc - Destination object of the copy
23 *
24 * RETURN: Status
25 *
26 * DESCRIPTION: Copy a buffer object to another buffer object.
27 *
28 ******************************************************************************/
29acpi_status
30acpi_ex_store_buffer_to_buffer(union acpi_operand_object *source_desc,
31 union acpi_operand_object *target_desc)
32{
33 u32 length;
34 u8 *buffer;
35
36 ACPI_FUNCTION_TRACE_PTR(ex_store_buffer_to_buffer, source_desc);
37
38 /* If Source and Target are the same, just return */
39
40 if (source_desc == target_desc) {
41 return_ACPI_STATUS(AE_OK);
42 }
43
44 /* We know that source_desc is a buffer by now */
45
46 buffer = ACPI_CAST_PTR(u8, source_desc->buffer.pointer);
47 length = source_desc->buffer.length;
48
49 /*
50 * If target is a buffer of length zero or is a static buffer,
51 * allocate a new buffer of the proper length
52 */
53 if ((target_desc->buffer.length == 0) ||
54 (target_desc->common.flags & AOPOBJ_STATIC_POINTER)) {
55 target_desc->buffer.pointer = ACPI_ALLOCATE(length);
56 if (!target_desc->buffer.pointer) {
57 return_ACPI_STATUS(AE_NO_MEMORY);
58 }
59
60 target_desc->buffer.length = length;
61 }
62
63 /* Copy source buffer to target buffer */
64
65 if (length <= target_desc->buffer.length) {
66
67 /* Clear existing buffer and copy in the new one */
68
69 memset(s: target_desc->buffer.pointer, c: 0,
70 n: target_desc->buffer.length);
71 memcpy(to: target_desc->buffer.pointer, from: buffer, len: length);
72
73#ifdef ACPI_OBSOLETE_BEHAVIOR
74 /*
75 * NOTE: ACPI versions up to 3.0 specified that the buffer must be
76 * truncated if the string is smaller than the buffer. However, "other"
77 * implementations of ACPI never did this and thus became the defacto
78 * standard. ACPI 3.0A changes this behavior such that the buffer
79 * is no longer truncated.
80 */
81
82 /*
83 * OBSOLETE BEHAVIOR:
84 * If the original source was a string, we must truncate the buffer,
85 * according to the ACPI spec. Integer-to-Buffer and Buffer-to-Buffer
86 * copy must not truncate the original buffer.
87 */
88 if (original_src_type == ACPI_TYPE_STRING) {
89
90 /* Set the new length of the target */
91
92 target_desc->buffer.length = length;
93 }
94#endif
95 } else {
96 /* Truncate the source, copy only what will fit */
97
98 memcpy(to: target_desc->buffer.pointer, from: buffer,
99 len: target_desc->buffer.length);
100
101 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
102 "Truncating source buffer from %X to %X\n",
103 length, target_desc->buffer.length));
104 }
105
106 /* Copy flags */
107
108 target_desc->buffer.flags = source_desc->buffer.flags;
109 target_desc->common.flags &= ~AOPOBJ_STATIC_POINTER;
110 return_ACPI_STATUS(AE_OK);
111}
112
113/*******************************************************************************
114 *
115 * FUNCTION: acpi_ex_store_string_to_string
116 *
117 * PARAMETERS: source_desc - Source object to copy
118 * target_desc - Destination object of the copy
119 *
120 * RETURN: Status
121 *
122 * DESCRIPTION: Copy a String object to another String object
123 *
124 ******************************************************************************/
125
126acpi_status
127acpi_ex_store_string_to_string(union acpi_operand_object *source_desc,
128 union acpi_operand_object *target_desc)
129{
130 u32 length;
131 u8 *buffer;
132
133 ACPI_FUNCTION_TRACE_PTR(ex_store_string_to_string, source_desc);
134
135 /* If Source and Target are the same, just return */
136
137 if (source_desc == target_desc) {
138 return_ACPI_STATUS(AE_OK);
139 }
140
141 /* We know that source_desc is a string by now */
142
143 buffer = ACPI_CAST_PTR(u8, source_desc->string.pointer);
144 length = source_desc->string.length;
145
146 /*
147 * Replace existing string value if it will fit and the string
148 * pointer is not a static pointer (part of an ACPI table)
149 */
150 if ((length < target_desc->string.length) &&
151 (!(target_desc->common.flags & AOPOBJ_STATIC_POINTER))) {
152 /*
153 * String will fit in existing non-static buffer.
154 * Clear old string and copy in the new one
155 */
156 memset(s: target_desc->string.pointer, c: 0,
157 n: (acpi_size)target_desc->string.length + 1);
158 memcpy(to: target_desc->string.pointer, from: buffer, len: length);
159 } else {
160 /*
161 * Free the current buffer, then allocate a new buffer
162 * large enough to hold the value
163 */
164 if (target_desc->string.pointer &&
165 (!(target_desc->common.flags & AOPOBJ_STATIC_POINTER))) {
166
167 /* Only free if not a pointer into the DSDT */
168
169 ACPI_FREE(target_desc->string.pointer);
170 }
171
172 target_desc->string.pointer =
173 ACPI_ALLOCATE_ZEROED((acpi_size)length + 1);
174
175 if (!target_desc->string.pointer) {
176 return_ACPI_STATUS(AE_NO_MEMORY);
177 }
178
179 target_desc->common.flags &= ~AOPOBJ_STATIC_POINTER;
180 memcpy(to: target_desc->string.pointer, from: buffer, len: length);
181 }
182
183 /* Set the new target length */
184
185 target_desc->string.length = length;
186 return_ACPI_STATUS(AE_OK);
187}
188