1 // SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
2 /*******************************************************************************
3  *
4  * Module Name: utstrtoul64 - String-to-integer conversion support for both
5  *                            64-bit and 32-bit integers
6  *
7  ******************************************************************************/
8 
9 #include <acpi/acpi.h>
10 #include "accommon.h"
11 
12 #define _COMPONENT          ACPI_UTILITIES
13 ACPI_MODULE_NAME("utstrtoul64")
14 
15 /*******************************************************************************
16  *
17  * This module contains the top-level string to 64/32-bit unsigned integer
18  * conversion functions:
19  *
20  *  1) A standard strtoul() function that supports 64-bit integers, base
21  *     8/10/16, with integer overflow support. This is used mainly by the
22  *     iASL compiler, which implements tighter constraints on integer
23  *     constants than the runtime (interpreter) integer-to-string conversions.
24  *  2) Runtime "Explicit conversion" as defined in the ACPI specification.
25  *  3) Runtime "Implicit conversion" as defined in the ACPI specification.
26  *
27  * Current users of this module:
28  *
29  *  iASL        - Preprocessor (constants and math expressions)
30  *  iASL        - Main parser, conversion of constants to integers
31  *  iASL        - Data Table Compiler parser (constants and math expressions)
32  *  interpreter - Implicit and explicit conversions, GPE method names
33  *  interpreter - Repair code for return values from predefined names
34  *  debugger    - Command line input string conversion
35  *  acpi_dump   - ACPI table physical addresses
36  *  acpi_exec   - Support for namespace overrides
37  *
38  * Notes concerning users of these interfaces:
39  *
40  * acpi_gbl_integer_byte_width is used to set the 32/64 bit limit for explicit
41  * and implicit conversions. This global must be set to the proper width.
42  * For the core ACPICA code, the width depends on the DSDT version. For the
43  * acpi_ut_strtoul64 interface, all conversions are 64 bits. This interface is
44  * used primarily for iASL, where the default width is 64 bits for all parsers,
45  * but error checking is performed later to flag cases where a 64-bit constant
46  * is wrongly defined in a 32-bit DSDT/SSDT.
47  *
48  * In ACPI, the only place where octal numbers are supported is within
49  * the ASL language itself. This is implemented via the main acpi_ut_strtoul64
50  * interface. According the ACPI specification, there is no ACPI runtime
51  * support (explicit/implicit) for octal string conversions.
52  *
53  ******************************************************************************/
54 /*******************************************************************************
55  *
56  * FUNCTION:    acpi_ut_strtoul64
57  *
58  * PARAMETERS:  string                  - Null terminated input string,
59  *                                        must be a valid pointer
60  *              return_value            - Where the converted integer is
61  *                                        returned. Must be a valid pointer
62  *
63  * RETURN:      Status and converted integer. Returns an exception on a
64  *              64-bit numeric overflow
65  *
66  * DESCRIPTION: Convert a string into an unsigned integer. Always performs a
67  *              full 64-bit conversion, regardless of the current global
68  *              integer width. Supports Decimal, Hex, and Octal strings.
69  *
70  * Current users of this function:
71  *
72  *  iASL        - Preprocessor (constants and math expressions)
73  *  iASL        - Main ASL parser, conversion of ASL constants to integers
74  *  iASL        - Data Table Compiler parser (constants and math expressions)
75  *  interpreter - Repair code for return values from predefined names
76  *  acpi_dump   - ACPI table physical addresses
77  *  acpi_exec   - Support for namespace overrides
78  *
79  ******************************************************************************/
80 acpi_status acpi_ut_strtoul64(char *string, u64 *return_value)
81 {
82 	acpi_status status = AE_OK;
83 	u8 original_bit_width;
84 	u32 base = 10;		/* Default is decimal */
85 
86 	ACPI_FUNCTION_TRACE_STR(ut_strtoul64, string);
87 
88 	*return_value = 0;
89 
90 	/* A NULL return string returns a value of zero */
91 
92 	if (*string == 0) {
93 		return_ACPI_STATUS(AE_OK);
94 	}
95 
96 	if (!acpi_ut_remove_whitespace(&string)) {
97 		return_ACPI_STATUS(AE_OK);
98 	}
99 
100 	/*
101 	 * 1) Check for a hex constant. A "0x" prefix indicates base 16.
102 	 */
103 	if (acpi_ut_detect_hex_prefix(&string)) {
104 		base = 16;
105 	}
106 
107 	/*
108 	 * 2) Check for an octal constant, defined to be a leading zero
109 	 * followed by sequence of octal digits (0-7)
110 	 */
111 	else if (acpi_ut_detect_octal_prefix(&string)) {
112 		base = 8;
113 	}
114 
115 	if (!acpi_ut_remove_leading_zeros(&string)) {
116 		return_ACPI_STATUS(AE_OK);	/* Return value 0 */
117 	}
118 
119 	/*
120 	 * Force a full 64-bit conversion. The caller (usually iASL) must
121 	 * check for a 32-bit overflow later as necessary (If current mode
122 	 * is 32-bit, meaning a 32-bit DSDT).
123 	 */
124 	original_bit_width = acpi_gbl_integer_bit_width;
125 	acpi_gbl_integer_bit_width = 64;
126 
127 	/*
128 	 * Perform the base 8, 10, or 16 conversion. A 64-bit numeric overflow
129 	 * will return an exception (to allow iASL to flag the statement).
130 	 */
131 	switch (base) {
132 	case 8:
133 		status = acpi_ut_convert_octal_string(string, return_value);
134 		break;
135 
136 	case 10:
137 		status = acpi_ut_convert_decimal_string(string, return_value);
138 		break;
139 
140 	case 16:
141 	default:
142 		status = acpi_ut_convert_hex_string(string, return_value);
143 		break;
144 	}
145 
146 	/* Only possible exception from above is a 64-bit overflow */
147 
148 	acpi_gbl_integer_bit_width = original_bit_width;
149 	return_ACPI_STATUS(status);
150 }
151 
152 /*******************************************************************************
153  *
154  * FUNCTION:    acpi_ut_implicit_strtoul64
155  *
156  * PARAMETERS:  string                  - Null terminated input string,
157  *                                        must be a valid pointer
158  *
159  * RETURN:      Converted integer
160  *
161  * DESCRIPTION: Perform a 64-bit conversion with restrictions placed upon
162  *              an "implicit conversion" by the ACPI specification. Used by
163  *              many ASL operators that require an integer operand, and support
164  *              an automatic (implicit) conversion from a string operand
165  *              to the final integer operand. The major restriction is that
166  *              only hex strings are supported.
167  *
168  * -----------------------------------------------------------------------------
169  *
170  * Base is always 16, either with or without the 0x prefix. Decimal and
171  * Octal strings are not supported, as per the ACPI specification.
172  *
173  * Examples (both are hex values):
174  *      Add ("BA98", Arg0, Local0)
175  *      Subtract ("0x12345678", Arg1, Local1)
176  *
177  * Conversion rules as extracted from the ACPI specification:
178  *
179  *  The converted integer is initialized to the value zero.
180  *  The ASCII string is always interpreted as a hexadecimal constant.
181  *
182  *  1)  According to the ACPI specification, a "0x" prefix is not allowed.
183  *      However, ACPICA allows this as an ACPI extension on general
184  *      principle. (NO ERROR)
185  *
186  *  2)  The conversion terminates when the size of an integer is reached
187  *      (32 or 64 bits). There are no numeric overflow conditions. (NO ERROR)
188  *
189  *  3)  The first non-hex character terminates the conversion and returns
190  *      the current accumulated value of the converted integer (NO ERROR).
191  *
192  *  4)  Conversion of a null (zero-length) string to an integer is
193  *      technically not allowed. However, ACPICA allows this as an ACPI
194  *      extension. The conversion returns the value 0. (NO ERROR)
195  *
196  * NOTE: There are no error conditions returned by this function. At
197  * the minimum, a value of zero is returned.
198  *
199  * Current users of this function:
200  *
201  *  interpreter - All runtime implicit conversions, as per ACPI specification
202  *  iASL        - Data Table Compiler parser (constants and math expressions)
203  *
204  ******************************************************************************/
205 
206 u64 acpi_ut_implicit_strtoul64(char *string)
207 {
208 	u64 converted_integer = 0;
209 
210 	ACPI_FUNCTION_TRACE_STR(ut_implicit_strtoul64, string);
211 
212 	if (!acpi_ut_remove_whitespace(&string)) {
213 		return_VALUE(0);
214 	}
215 
216 	/*
217 	 * Per the ACPI specification, only hexadecimal is supported for
218 	 * implicit conversions, and the "0x" prefix is "not allowed".
219 	 * However, allow a "0x" prefix as an ACPI extension.
220 	 */
221 	acpi_ut_remove_hex_prefix(&string);
222 
223 	if (!acpi_ut_remove_leading_zeros(&string)) {
224 		return_VALUE(0);
225 	}
226 
227 	/*
228 	 * Ignore overflow as per the ACPI specification. This is implemented by
229 	 * ignoring the return status from the conversion function called below.
230 	 * On overflow, the input string is simply truncated.
231 	 */
232 	acpi_ut_convert_hex_string(string, &converted_integer);
233 	return_VALUE(converted_integer);
234 }
235 
236 /*******************************************************************************
237  *
238  * FUNCTION:    acpi_ut_explicit_strtoul64
239  *
240  * PARAMETERS:  string                  - Null terminated input string,
241  *                                        must be a valid pointer
242  *
243  * RETURN:      Converted integer
244  *
245  * DESCRIPTION: Perform a 64-bit conversion with the restrictions placed upon
246  *              an "explicit conversion" by the ACPI specification. The
247  *              main restriction is that only hex and decimal are supported.
248  *
249  * -----------------------------------------------------------------------------
250  *
251  * Base is either 10 (default) or 16 (with 0x prefix). Octal (base 8) strings
252  * are not supported, as per the ACPI specification.
253  *
254  * Examples:
255  *      to_integer ("1000")     Decimal
256  *      to_integer ("0xABCD")   Hex
257  *
258  * Conversion rules as extracted from the ACPI specification:
259  *
260  *  1)  The input string is either a decimal or hexadecimal numeric string.
261  *      A hex value must be prefixed by "0x" or it is interpreted as decimal.
262  *
263  *  2)  The value must not exceed the maximum of an integer value
264  *      (32 or 64 bits). The ACPI specification states the behavior is
265  *      "unpredictable", so ACPICA matches the behavior of the implicit
266  *      conversion case. There are no numeric overflow conditions. (NO ERROR)
267  *
268  *  3)  Behavior on the first non-hex character is not defined by the ACPI
269  *      specification (for the to_integer operator), so ACPICA matches the
270  *      behavior of the implicit conversion case. It terminates the
271  *      conversion and returns the current accumulated value of the converted
272  *      integer. (NO ERROR)
273  *
274  *  4)  Conversion of a null (zero-length) string to an integer is
275  *      technically not allowed. However, ACPICA allows this as an ACPI
276  *      extension. The conversion returns the value 0. (NO ERROR)
277  *
278  * NOTE: There are no error conditions returned by this function. At the
279  * minimum, a value of zero is returned.
280  *
281  * Current users of this function:
282  *
283  *  interpreter - Runtime ASL to_integer operator, as per the ACPI specification
284  *
285  ******************************************************************************/
286 
287 u64 acpi_ut_explicit_strtoul64(char *string)
288 {
289 	u64 converted_integer = 0;
290 	u32 base = 10;		/* Default is decimal */
291 
292 	ACPI_FUNCTION_TRACE_STR(ut_explicit_strtoul64, string);
293 
294 	if (!acpi_ut_remove_whitespace(&string)) {
295 		return_VALUE(0);
296 	}
297 
298 	/*
299 	 * Only Hex and Decimal are supported, as per the ACPI specification.
300 	 * A "0x" prefix indicates hex; otherwise decimal is assumed.
301 	 */
302 	if (acpi_ut_detect_hex_prefix(&string)) {
303 		base = 16;
304 	}
305 
306 	if (!acpi_ut_remove_leading_zeros(&string)) {
307 		return_VALUE(0);
308 	}
309 
310 	/*
311 	 * Ignore overflow as per the ACPI specification. This is implemented by
312 	 * ignoring the return status from the conversion functions called below.
313 	 * On overflow, the input string is simply truncated.
314 	 */
315 	switch (base) {
316 	case 10:
317 	default:
318 		acpi_ut_convert_decimal_string(string, &converted_integer);
319 		break;
320 
321 	case 16:
322 		acpi_ut_convert_hex_string(string, &converted_integer);
323 		break;
324 	}
325 
326 	return_VALUE(converted_integer);
327 }
328