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 - 2023, 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(target_desc->buffer.pointer, 0,
70		       target_desc->buffer.length);
71		memcpy(target_desc->buffer.pointer, buffer, 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(target_desc->buffer.pointer, buffer,
99		       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(target_desc->string.pointer, 0,
157		       (acpi_size)target_desc->string.length + 1);
158		memcpy(target_desc->string.pointer, buffer, 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(target_desc->string.pointer, buffer, length);
181	}
182
183	/* Set the new target length */
184
185	target_desc->string.length = length;
186	return_ACPI_STATUS(AE_OK);
187}
188