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1// SPDX-License-Identifier: GPL-2.0-only
2#include "test_util.h"
3#include "kvm_util.h"
4#include "ucall_common.h"
5
6#define APPEND_BUFFER_SAFE(str, end, v) \
7do { \
8 GUEST_ASSERT(str < end); \
9 *str++ = (v); \
10} while (0)
11
12static int isdigit(int ch)
13{
14 return (ch >= '0') && (ch <= '9');
15}
16
17static int skip_atoi(const char **s)
18{
19 int i = 0;
20
21 while (isdigit(**s))
22 i = i * 10 + *((*s)++) - '0';
23 return i;
24}
25
26#define ZEROPAD 1 /* pad with zero */
27#define SIGN 2 /* unsigned/signed long */
28#define PLUS 4 /* show plus */
29#define SPACE 8 /* space if plus */
30#define LEFT 16 /* left justified */
31#define SMALL 32 /* Must be 32 == 0x20 */
32#define SPECIAL 64 /* 0x */
33
34#define __do_div(n, base) \
35({ \
36 int __res; \
37 \
38 __res = ((u64)n) % (u32)base; \
39 n = ((u64)n) / (u32)base; \
40 __res; \
41})
42
43static char *number(char *str, const char *end, long num, int base, int size,
44 int precision, int type)
45{
46 /* we are called with base 8, 10 or 16, only, thus don't need "G..." */
47 static const char digits[16] = "0123456789ABCDEF"; /* "GHIJKLMNOPQRSTUVWXYZ"; */
48
49 char tmp[66];
50 char c, sign, locase;
51 int i;
52
53 /*
54 * locase = 0 or 0x20. ORing digits or letters with 'locase'
55 * produces same digits or (maybe lowercased) letters
56 */
57 locase = (type & SMALL);
58 if (type & LEFT)
59 type &= ~ZEROPAD;
60 if (base < 2 || base > 16)
61 return NULL;
62 c = (type & ZEROPAD) ? '0' : ' ';
63 sign = 0;
64 if (type & SIGN) {
65 if (num < 0) {
66 sign = '-';
67 num = -num;
68 size--;
69 } else if (type & PLUS) {
70 sign = '+';
71 size--;
72 } else if (type & SPACE) {
73 sign = ' ';
74 size--;
75 }
76 }
77 if (type & SPECIAL) {
78 if (base == 16)
79 size -= 2;
80 else if (base == 8)
81 size--;
82 }
83 i = 0;
84 if (num == 0)
85 tmp[i++] = '0';
86 else
87 while (num != 0)
88 tmp[i++] = (digits[__do_div(num, base)] | locase);
89 if (i > precision)
90 precision = i;
91 size -= precision;
92 if (!(type & (ZEROPAD + LEFT)))
93 while (size-- > 0)
94 APPEND_BUFFER_SAFE(str, end, ' ');
95 if (sign)
96 APPEND_BUFFER_SAFE(str, end, sign);
97 if (type & SPECIAL) {
98 if (base == 8)
99 APPEND_BUFFER_SAFE(str, end, '0');
100 else if (base == 16) {
101 APPEND_BUFFER_SAFE(str, end, '0');
102 APPEND_BUFFER_SAFE(str, end, 'x');
103 }
104 }
105 if (!(type & LEFT))
106 while (size-- > 0)
107 APPEND_BUFFER_SAFE(str, end, c);
108 while (i < precision--)
109 APPEND_BUFFER_SAFE(str, end, '0');
110 while (i-- > 0)
111 APPEND_BUFFER_SAFE(str, end, tmp[i]);
112 while (size-- > 0)
113 APPEND_BUFFER_SAFE(str, end, ' ');
114
115 return str;
116}
117
118int guest_vsnprintf(char *buf, int n, const char *fmt, va_list args)
119{
120 char *str, *end;
121 const char *s;
122 u64 num;
123 int i, base;
124 int len;
125
126 int flags; /* flags to number() */
127
128 int field_width; /* width of output field */
129 int precision; /*
130 * min. # of digits for integers; max
131 * number of chars for from string
132 */
133 int qualifier; /* 'h', 'l', or 'L' for integer fields */
134
135 end = buf + n;
136 GUEST_ASSERT(buf < end);
137 GUEST_ASSERT(n > 0);
138
139 for (str = buf; *fmt; ++fmt) {
140 if (*fmt != '%') {
141 APPEND_BUFFER_SAFE(str, end, *fmt);
142 continue;
143 }
144
145 /* process flags */
146 flags = 0;
147repeat:
148 ++fmt; /* this also skips first '%' */
149 switch (*fmt) {
150 case '-':
151 flags |= LEFT;
152 goto repeat;
153 case '+':
154 flags |= PLUS;
155 goto repeat;
156 case ' ':
157 flags |= SPACE;
158 goto repeat;
159 case '#':
160 flags |= SPECIAL;
161 goto repeat;
162 case '0':
163 flags |= ZEROPAD;
164 goto repeat;
165 }
166
167 /* get field width */
168 field_width = -1;
169 if (isdigit(*fmt))
170 field_width = skip_atoi(&fmt);
171 else if (*fmt == '*') {
172 ++fmt;
173 /* it's the next argument */
174 field_width = va_arg(args, int);
175 if (field_width < 0) {
176 field_width = -field_width;
177 flags |= LEFT;
178 }
179 }
180
181 /* get the precision */
182 precision = -1;
183 if (*fmt == '.') {
184 ++fmt;
185 if (isdigit(*fmt))
186 precision = skip_atoi(&fmt);
187 else if (*fmt == '*') {
188 ++fmt;
189 /* it's the next argument */
190 precision = va_arg(args, int);
191 }
192 if (precision < 0)
193 precision = 0;
194 }
195
196 /* get the conversion qualifier */
197 qualifier = -1;
198 if (*fmt == 'h' || *fmt == 'l' || *fmt == 'L') {
199 qualifier = *fmt;
200 ++fmt;
201 }
202
203 /*
204 * Play nice with %llu, %llx, etc. KVM selftests only support
205 * 64-bit builds, so just treat %ll* the same as %l*.
206 */
207 if (qualifier == 'l' && *fmt == 'l')
208 ++fmt;
209
210 /* default base */
211 base = 10;
212
213 switch (*fmt) {
214 case 'c':
215 if (!(flags & LEFT))
216 while (--field_width > 0)
217 APPEND_BUFFER_SAFE(str, end, ' ');
218 APPEND_BUFFER_SAFE(str, end,
219 (u8)va_arg(args, int));
220 while (--field_width > 0)
221 APPEND_BUFFER_SAFE(str, end, ' ');
222 continue;
223
224 case 's':
225 s = va_arg(args, char *);
226 len = strnlen(s, precision);
227
228 if (!(flags & LEFT))
229 while (len < field_width--)
230 APPEND_BUFFER_SAFE(str, end, ' ');
231 for (i = 0; i < len; ++i)
232 APPEND_BUFFER_SAFE(str, end, *s++);
233 while (len < field_width--)
234 APPEND_BUFFER_SAFE(str, end, ' ');
235 continue;
236
237 case 'p':
238 if (field_width == -1) {
239 field_width = 2 * sizeof(void *);
240 flags |= SPECIAL | SMALL | ZEROPAD;
241 }
242 str = number(str, end,
243 (u64)va_arg(args, void *), 16,
244 field_width, precision, flags);
245 continue;
246
247 case 'n':
248 if (qualifier == 'l') {
249 long *ip = va_arg(args, long *);
250 *ip = (str - buf);
251 } else {
252 int *ip = va_arg(args, int *);
253 *ip = (str - buf);
254 }
255 continue;
256
257 case '%':
258 APPEND_BUFFER_SAFE(str, end, '%');
259 continue;
260
261 /* integer number formats - set up the flags and "break" */
262 case 'o':
263 base = 8;
264 break;
265
266 case 'x':
267 flags |= SMALL;
268 case 'X':
269 base = 16;
270 break;
271
272 case 'd':
273 case 'i':
274 flags |= SIGN;
275 case 'u':
276 break;
277
278 default:
279 APPEND_BUFFER_SAFE(str, end, '%');
280 if (*fmt)
281 APPEND_BUFFER_SAFE(str, end, *fmt);
282 else
283 --fmt;
284 continue;
285 }
286 if (qualifier == 'l')
287 num = va_arg(args, u64);
288 else if (qualifier == 'h') {
289 num = (u16)va_arg(args, int);
290 if (flags & SIGN)
291 num = (s16)num;
292 } else if (flags & SIGN)
293 num = va_arg(args, int);
294 else
295 num = va_arg(args, u32);
296 str = number(str, end, num, base, field_width, precision, flags);
297 }
298
299 GUEST_ASSERT(str < end);
300 *str = '\0';
301 return str - buf;
302}
303
304int guest_snprintf(char *buf, int n, const char *fmt, ...)
305{
306 va_list va;
307 int len;
308
309 va_start(va, fmt);
310 len = guest_vsnprintf(buf, n, fmt, va);
311 va_end(va);
312
313 return len;
314}