drivers/acpi/acpica/exstorob.c

   1 /******************************************************************************
   2  *
   3  * Module Name: exstorob - AML object store support, store to object
   4  *
   5  *****************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2018, Intel Corp.
   9  * All rights reserved.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions, and the following disclaimer,
  16  *    without modification.
  17  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
  18  *    substantially similar to the "NO WARRANTY" disclaimer below
  19  *    ("Disclaimer") and any redistribution must be conditioned upon
  20  *    including a substantially similar Disclaimer requirement for further
  21  *    binary redistribution.
  22  * 3. Neither the names of the above-listed copyright holders nor the names
  23  *    of any contributors may be used to endorse or promote products derived
  24  *    from this software without specific prior written permission.
  25  *
  26  * Alternatively, this software may be distributed under the terms of the
  27  * GNU General Public License ("GPL") version 2 as published by the Free
  28  * Software Foundation.
  29  *
  30  * NO WARRANTY
  31  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  32  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  33  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
  34  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  35  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  36  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  37  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  38  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  39  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  40  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  41  * POSSIBILITY OF SUCH DAMAGES.
  42  */
  43
  44 #include <acpi/acpi.h>
  45 #include "accommon.h"
  46 #include "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         /* If Source and Target are the same, just return */
  73
  74         if (source_desc == target_desc) {
  75                 return_ACPI_STATUS(AE_OK);
  76         }
  77
  78         /* We know that source_desc is a buffer by now */
  79
  80         buffer = ACPI_CAST_PTR(u8, source_desc->buffer.pointer);
  81         length = source_desc->buffer.length;
  82
  83         /*
  84          * If target is a buffer of length zero or is a static buffer,
  85          * allocate a new buffer of the proper length
  86          */
  87         if ((target_desc->buffer.length == 0) ||
  88             (target_desc->common.flags & AOPOBJ_STATIC_POINTER)) {
  89                 target_desc->buffer.pointer = ACPI_ALLOCATE(length);
  90                 if (!target_desc->buffer.pointer) {
  91                         return_ACPI_STATUS(AE_NO_MEMORY);
  92                 }
  93
  94                 target_desc->buffer.length = length;
  95         }
  96
  97         /* Copy source buffer to target buffer */
  98
  99         if (length <= target_desc->buffer.length) {
 100
 101                 /* Clear existing buffer and copy in the new one */
 102
 103                 memset(target_desc->buffer.pointer, 0,
 104                        target_desc->buffer.length);
 105                 memcpy(target_desc->buffer.pointer, buffer, length);
 106
 107 #ifdef ACPI_OBSOLETE_BEHAVIOR
 108                 /*
 109                  * NOTE: ACPI versions up to 3.0 specified that the buffer must be
 110                  * truncated if the string is smaller than the buffer. However, "other"
 111                  * implementations of ACPI never did this and thus became the defacto
 112                  * standard. ACPI 3.0A changes this behavior such that the buffer
 113                  * is no longer truncated.
 114                  */
 115
 116                 /*
 117                  * OBSOLETE BEHAVIOR:
 118                  * If the original source was a string, we must truncate the buffer,
 119                  * according to the ACPI spec. Integer-to-Buffer and Buffer-to-Buffer
 120                  * copy must not truncate the original buffer.
 121                  */
 122                 if (original_src_type == ACPI_TYPE_STRING) {
 123
 124                         /* Set the new length of the target */
 125
 126                         target_desc->buffer.length = length;
 127                 }
 128 #endif
 129         } else {
 130                 /* Truncate the source, copy only what will fit */
 131
 132                 memcpy(target_desc->buffer.pointer, buffer,
 133                        target_desc->buffer.length);
 134
 135                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 136                                   "Truncating source buffer from %X to %X\n",
 137                                   length, target_desc->buffer.length));
 138         }
 139
 140         /* Copy flags */
 141
 142         target_desc->buffer.flags = source_desc->buffer.flags;
 143         target_desc->common.flags &= ~AOPOBJ_STATIC_POINTER;
 144         return_ACPI_STATUS(AE_OK);
 145 }
 146
 147 /*******************************************************************************
 148  *
 149  * FUNCTION:    acpi_ex_store_string_to_string
 150  *
 151  * PARAMETERS:  source_desc         - Source object to copy
 152  *              target_desc         - Destination object of the copy
 153  *
 154  * RETURN:      Status
 155  *
 156  * DESCRIPTION: Copy a String object to another String object
 157  *
 158  ******************************************************************************/
 159
 160 acpi_status
 161 acpi_ex_store_string_to_string(union acpi_operand_object *source_desc,
 162                                union acpi_operand_object *target_desc)
 163 {
 164         u32 length;
 165         u8 *buffer;
 166
 167         ACPI_FUNCTION_TRACE_PTR(ex_store_string_to_string, source_desc);
 168
 169         /* If Source and Target are the same, just return */
 170
 171         if (source_desc == target_desc) {
 172                 return_ACPI_STATUS(AE_OK);
 173         }
 174
 175         /* We know that source_desc is a string by now */
 176
 177         buffer = ACPI_CAST_PTR(u8, source_desc->string.pointer);
 178         length = source_desc->string.length;
 179
 180         /*
 181          * Replace existing string value if it will fit and the string
 182          * pointer is not a static pointer (part of an ACPI table)
 183          */
 184         if ((length < target_desc->string.length) &&
 185             (!(target_desc->common.flags & AOPOBJ_STATIC_POINTER))) {
 186                 /*
 187                  * String will fit in existing non-static buffer.
 188                  * Clear old string and copy in the new one
 189                  */
 190                 memset(target_desc->string.pointer, 0,
 191                        (acpi_size)target_desc->string.length + 1);
 192                 memcpy(target_desc->string.pointer, buffer, length);
 193         } else {
 194                 /*
 195                  * Free the current buffer, then allocate a new buffer
 196                  * large enough to hold the value
 197                  */
 198                 if (target_desc->string.pointer &&
 199                     (!(target_desc->common.flags & AOPOBJ_STATIC_POINTER))) {
 200
 201                         /* Only free if not a pointer into the DSDT */
 202
 203                         ACPI_FREE(target_desc->string.pointer);
 204                 }
 205
 206                 target_desc->string.pointer =
 207                     ACPI_ALLOCATE_ZEROED((acpi_size)length + 1);
 208
 209                 if (!target_desc->string.pointer) {
 210                         return_ACPI_STATUS(AE_NO_MEMORY);
 211                 }
 212
 213                 target_desc->common.flags &= ~AOPOBJ_STATIC_POINTER;
 214                 memcpy(target_desc->string.pointer, buffer, length);
 215         }
 216
 217         /* Set the new target length */
 218
 219         target_desc->string.length = length;
 220         return_ACPI_STATUS(AE_OK);
 221 }