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) \
7 do {					\
8 	GUEST_ASSERT(str < end);	\
9 	*str++ = (v);			\
10 } while (0)
11 
isdigit(int ch)12 static int isdigit(int ch)
13 {
14 	return (ch >= '0') && (ch <= '9');
15 }
16 
skip_atoi(const char ** s)17 static 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 = ((uint64_t) n) % (uint32_t) base;	\
39 	n = ((uint64_t) n) / (uint32_t) base;		\
40 	__res;						\
41 })
42 
number(char * str,const char * end,long num,int base,int size,int precision,int type)43 static 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 
guest_vsnprintf(char * buf,int n,const char * fmt,va_list args)118 int guest_vsnprintf(char *buf, int n, const char *fmt, va_list args)
119 {
120 	char *str, *end;
121 	const char *s;
122 	uint64_t 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;
147 repeat:
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 					    (uint8_t)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 				     (uint64_t)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, uint64_t);
288 		else if (qualifier == 'h') {
289 			num = (uint16_t)va_arg(args, int);
290 			if (flags & SIGN)
291 				num = (int16_t)num;
292 		} else if (flags & SIGN)
293 			num = va_arg(args, int);
294 		else
295 			num = va_arg(args, uint32_t);
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 
guest_snprintf(char * buf,int n,const char * fmt,...)304 int 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 }
315