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 - 2022, Intel Corp.
7  *
8  *****************************************************************************/
9 
10 #include <acpi/acpi.h>
11 #include "accommon.h"
12 #include "acinterp.h"
13 
14 #define _COMPONENT          ACPI_EXECUTER
15 ACPI_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  ******************************************************************************/
29 acpi_status
acpi_ex_store_buffer_to_buffer(union acpi_operand_object * source_desc,union acpi_operand_object * target_desc)30 acpi_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 
126 acpi_status
acpi_ex_store_string_to_string(union acpi_operand_object * source_desc,union acpi_operand_object * target_desc)127 acpi_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