Root/lib/kstrtox.c

1/*
2 * Convert integer string representation to an integer.
3 * If an integer doesn't fit into specified type, -E is returned.
4 *
5 * Integer starts with optional sign.
6 * kstrtou*() functions do not accept sign "-".
7 *
8 * Radix 0 means autodetection: leading "0x" implies radix 16,
9 * leading "0" implies radix 8, otherwise radix is 10.
10 * Autodetection hints work after optional sign, but not before.
11 *
12 * If -E is returned, result is not touched.
13 */
14#include <linux/ctype.h>
15#include <linux/errno.h>
16#include <linux/kernel.h>
17#include <linux/math64.h>
18#include <linux/export.h>
19#include <linux/types.h>
20#include <asm/uaccess.h>
21#include "kstrtox.h"
22
23const char *_parse_integer_fixup_radix(const char *s, unsigned int *base)
24{
25    if (*base == 0) {
26        if (s[0] == '0') {
27            if (_tolower(s[1]) == 'x' && isxdigit(s[2]))
28                *base = 16;
29            else
30                *base = 8;
31        } else
32            *base = 10;
33    }
34    if (*base == 16 && s[0] == '0' && _tolower(s[1]) == 'x')
35        s += 2;
36    return s;
37}
38
39/*
40 * Convert non-negative integer string representation in explicitly given radix
41 * to an integer.
42 * Return number of characters consumed maybe or-ed with overflow bit.
43 * If overflow occurs, result integer (incorrect) is still returned.
44 *
45 * Don't you dare use this function.
46 */
47unsigned int _parse_integer(const char *s, unsigned int base, unsigned long long *p)
48{
49    unsigned long long res;
50    unsigned int rv;
51    int overflow;
52
53    res = 0;
54    rv = 0;
55    overflow = 0;
56    while (*s) {
57        unsigned int val;
58
59        if ('0' <= *s && *s <= '9')
60            val = *s - '0';
61        else if ('a' <= _tolower(*s) && _tolower(*s) <= 'f')
62            val = _tolower(*s) - 'a' + 10;
63        else
64            break;
65
66        if (val >= base)
67            break;
68        /*
69         * Check for overflow only if we are within range of
70         * it in the max base we support (16)
71         */
72        if (unlikely(res & (~0ull << 60))) {
73            if (res > div_u64(ULLONG_MAX - val, base))
74                overflow = 1;
75        }
76        res = res * base + val;
77        rv++;
78        s++;
79    }
80    *p = res;
81    if (overflow)
82        rv |= KSTRTOX_OVERFLOW;
83    return rv;
84}
85
86static int _kstrtoull(const char *s, unsigned int base, unsigned long long *res)
87{
88    unsigned long long _res;
89    unsigned int rv;
90
91    s = _parse_integer_fixup_radix(s, &base);
92    rv = _parse_integer(s, base, &_res);
93    if (rv & KSTRTOX_OVERFLOW)
94        return -ERANGE;
95    rv &= ~KSTRTOX_OVERFLOW;
96    if (rv == 0)
97        return -EINVAL;
98    s += rv;
99    if (*s == '\n')
100        s++;
101    if (*s)
102        return -EINVAL;
103    *res = _res;
104    return 0;
105}
106
107/**
108 * kstrtoull - convert a string to an unsigned long long
109 * @s: The start of the string. The string must be null-terminated, and may also
110 * include a single newline before its terminating null. The first character
111 * may also be a plus sign, but not a minus sign.
112 * @base: The number base to use. The maximum supported base is 16. If base is
113 * given as 0, then the base of the string is automatically detected with the
114 * conventional semantics - If it begins with 0x the number will be parsed as a
115 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be
116 * parsed as an octal number. Otherwise it will be parsed as a decimal.
117 * @res: Where to write the result of the conversion on success.
118 *
119 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
120 * Used as a replacement for the obsolete simple_strtoull. Return code must
121 * be checked.
122 */
123int kstrtoull(const char *s, unsigned int base, unsigned long long *res)
124{
125    if (s[0] == '+')
126        s++;
127    return _kstrtoull(s, base, res);
128}
129EXPORT_SYMBOL(kstrtoull);
130
131/**
132 * kstrtoll - convert a string to a long long
133 * @s: The start of the string. The string must be null-terminated, and may also
134 * include a single newline before its terminating null. The first character
135 * may also be a plus sign or a minus sign.
136 * @base: The number base to use. The maximum supported base is 16. If base is
137 * given as 0, then the base of the string is automatically detected with the
138 * conventional semantics - If it begins with 0x the number will be parsed as a
139 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be
140 * parsed as an octal number. Otherwise it will be parsed as a decimal.
141 * @res: Where to write the result of the conversion on success.
142 *
143 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
144 * Used as a replacement for the obsolete simple_strtoull. Return code must
145 * be checked.
146 */
147int kstrtoll(const char *s, unsigned int base, long long *res)
148{
149    unsigned long long tmp;
150    int rv;
151
152    if (s[0] == '-') {
153        rv = _kstrtoull(s + 1, base, &tmp);
154        if (rv < 0)
155            return rv;
156        if ((long long)(-tmp) >= 0)
157            return -ERANGE;
158        *res = -tmp;
159    } else {
160        rv = kstrtoull(s, base, &tmp);
161        if (rv < 0)
162            return rv;
163        if ((long long)tmp < 0)
164            return -ERANGE;
165        *res = tmp;
166    }
167    return 0;
168}
169EXPORT_SYMBOL(kstrtoll);
170
171/* Internal, do not use. */
172int _kstrtoul(const char *s, unsigned int base, unsigned long *res)
173{
174    unsigned long long tmp;
175    int rv;
176
177    rv = kstrtoull(s, base, &tmp);
178    if (rv < 0)
179        return rv;
180    if (tmp != (unsigned long long)(unsigned long)tmp)
181        return -ERANGE;
182    *res = tmp;
183    return 0;
184}
185EXPORT_SYMBOL(_kstrtoul);
186
187/* Internal, do not use. */
188int _kstrtol(const char *s, unsigned int base, long *res)
189{
190    long long tmp;
191    int rv;
192
193    rv = kstrtoll(s, base, &tmp);
194    if (rv < 0)
195        return rv;
196    if (tmp != (long long)(long)tmp)
197        return -ERANGE;
198    *res = tmp;
199    return 0;
200}
201EXPORT_SYMBOL(_kstrtol);
202
203/**
204 * kstrtouint - convert a string to an unsigned int
205 * @s: The start of the string. The string must be null-terminated, and may also
206 * include a single newline before its terminating null. The first character
207 * may also be a plus sign, but not a minus sign.
208 * @base: The number base to use. The maximum supported base is 16. If base is
209 * given as 0, then the base of the string is automatically detected with the
210 * conventional semantics - If it begins with 0x the number will be parsed as a
211 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be
212 * parsed as an octal number. Otherwise it will be parsed as a decimal.
213 * @res: Where to write the result of the conversion on success.
214 *
215 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
216 * Used as a replacement for the obsolete simple_strtoull. Return code must
217 * be checked.
218 */
219int kstrtouint(const char *s, unsigned int base, unsigned int *res)
220{
221    unsigned long long tmp;
222    int rv;
223
224    rv = kstrtoull(s, base, &tmp);
225    if (rv < 0)
226        return rv;
227    if (tmp != (unsigned long long)(unsigned int)tmp)
228        return -ERANGE;
229    *res = tmp;
230    return 0;
231}
232EXPORT_SYMBOL(kstrtouint);
233
234/**
235 * kstrtoint - convert a string to an int
236 * @s: The start of the string. The string must be null-terminated, and may also
237 * include a single newline before its terminating null. The first character
238 * may also be a plus sign or a minus sign.
239 * @base: The number base to use. The maximum supported base is 16. If base is
240 * given as 0, then the base of the string is automatically detected with the
241 * conventional semantics - If it begins with 0x the number will be parsed as a
242 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be
243 * parsed as an octal number. Otherwise it will be parsed as a decimal.
244 * @res: Where to write the result of the conversion on success.
245 *
246 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
247 * Used as a replacement for the obsolete simple_strtoull. Return code must
248 * be checked.
249 */
250int kstrtoint(const char *s, unsigned int base, int *res)
251{
252    long long tmp;
253    int rv;
254
255    rv = kstrtoll(s, base, &tmp);
256    if (rv < 0)
257        return rv;
258    if (tmp != (long long)(int)tmp)
259        return -ERANGE;
260    *res = tmp;
261    return 0;
262}
263EXPORT_SYMBOL(kstrtoint);
264
265int kstrtou16(const char *s, unsigned int base, u16 *res)
266{
267    unsigned long long tmp;
268    int rv;
269
270    rv = kstrtoull(s, base, &tmp);
271    if (rv < 0)
272        return rv;
273    if (tmp != (unsigned long long)(u16)tmp)
274        return -ERANGE;
275    *res = tmp;
276    return 0;
277}
278EXPORT_SYMBOL(kstrtou16);
279
280int kstrtos16(const char *s, unsigned int base, s16 *res)
281{
282    long long tmp;
283    int rv;
284
285    rv = kstrtoll(s, base, &tmp);
286    if (rv < 0)
287        return rv;
288    if (tmp != (long long)(s16)tmp)
289        return -ERANGE;
290    *res = tmp;
291    return 0;
292}
293EXPORT_SYMBOL(kstrtos16);
294
295int kstrtou8(const char *s, unsigned int base, u8 *res)
296{
297    unsigned long long tmp;
298    int rv;
299
300    rv = kstrtoull(s, base, &tmp);
301    if (rv < 0)
302        return rv;
303    if (tmp != (unsigned long long)(u8)tmp)
304        return -ERANGE;
305    *res = tmp;
306    return 0;
307}
308EXPORT_SYMBOL(kstrtou8);
309
310int kstrtos8(const char *s, unsigned int base, s8 *res)
311{
312    long long tmp;
313    int rv;
314
315    rv = kstrtoll(s, base, &tmp);
316    if (rv < 0)
317        return rv;
318    if (tmp != (long long)(s8)tmp)
319        return -ERANGE;
320    *res = tmp;
321    return 0;
322}
323EXPORT_SYMBOL(kstrtos8);
324
325#define kstrto_from_user(f, g, type) \
326int f(const char __user *s, size_t count, unsigned int base, type *res) \
327{ \
328    /* sign, base 2 representation, newline, terminator */ \
329    char buf[1 + sizeof(type) * 8 + 1 + 1]; \
330                                    \
331    count = min(count, sizeof(buf) - 1); \
332    if (copy_from_user(buf, s, count)) \
333        return -EFAULT; \
334    buf[count] = '\0'; \
335    return g(buf, base, res); \
336} \
337EXPORT_SYMBOL(f)
338
339kstrto_from_user(kstrtoull_from_user, kstrtoull, unsigned long long);
340kstrto_from_user(kstrtoll_from_user, kstrtoll, long long);
341kstrto_from_user(kstrtoul_from_user, kstrtoul, unsigned long);
342kstrto_from_user(kstrtol_from_user, kstrtol, long);
343kstrto_from_user(kstrtouint_from_user, kstrtouint, unsigned int);
344kstrto_from_user(kstrtoint_from_user, kstrtoint, int);
345kstrto_from_user(kstrtou16_from_user, kstrtou16, u16);
346kstrto_from_user(kstrtos16_from_user, kstrtos16, s16);
347kstrto_from_user(kstrtou8_from_user, kstrtou8, u8);
348kstrto_from_user(kstrtos8_from_user, kstrtos8, s8);
349

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