1 // SPDX-License-Identifier: GPL-2.0
2 #include <sys/types.h>
3 #include <stdio.h>
4 #include <stdlib.h>
5 #include <string.h>
6 #include "symbol.h"
7 
8 #include "demangle-java.h"
9 
10 #include <linux/ctype.h>
11 #include <linux/kernel.h>
12 
13 enum {
14 	MODE_PREFIX = 0,
15 	MODE_CLASS  = 1,
16 	MODE_FUNC   = 2,
17 	MODE_TYPE   = 3,
18 	MODE_CTYPE  = 4, /* class arg */
19 };
20 
21 #define BASE_ENT(c, n)	[c - 'A']=n
22 static const char *base_types['Z' - 'A' + 1] = {
23 	BASE_ENT('B', "byte" ),
24 	BASE_ENT('C', "char" ),
25 	BASE_ENT('D', "double" ),
26 	BASE_ENT('F', "float" ),
27 	BASE_ENT('I', "int" ),
28 	BASE_ENT('J', "long" ),
29 	BASE_ENT('S', "short" ),
30 	BASE_ENT('Z', "boolean" ),
31 };
32 
33 /*
34  * demangle Java symbol between str and end positions and stores
35  * up to maxlen characters into buf. The parser starts in mode.
36  *
37  * Use MODE_PREFIX to process entire prototype till end position
38  * Use MODE_TYPE to process return type if str starts on return type char
39  *
40  *  Return:
41  *	success: buf
42  *	error  : NULL
43  */
44 static char *
__demangle_java_sym(const char * str,const char * end,char * buf,int maxlen,int mode)45 __demangle_java_sym(const char *str, const char *end, char *buf, int maxlen, int mode)
46 {
47 	int rlen = 0;
48 	int array = 0;
49 	int narg = 0;
50 	const char *q;
51 
52 	if (!end)
53 		end = str + strlen(str);
54 
55 	for (q = str; q != end; q++) {
56 
57 		if (rlen == (maxlen - 1))
58 			break;
59 
60 		switch (*q) {
61 		case 'L':
62 			if (mode == MODE_PREFIX || mode == MODE_TYPE) {
63 				if (mode == MODE_TYPE) {
64 					if (narg)
65 						rlen += scnprintf(buf + rlen, maxlen - rlen, ", ");
66 					narg++;
67 				}
68 				if (mode == MODE_PREFIX)
69 					mode = MODE_CLASS;
70 				else
71 					mode = MODE_CTYPE;
72 			} else
73 				buf[rlen++] = *q;
74 			break;
75 		case 'B':
76 		case 'C':
77 		case 'D':
78 		case 'F':
79 		case 'I':
80 		case 'J':
81 		case 'S':
82 		case 'Z':
83 			if (mode == MODE_TYPE) {
84 				if (narg)
85 					rlen += scnprintf(buf + rlen, maxlen - rlen, ", ");
86 				rlen += scnprintf(buf + rlen, maxlen - rlen, "%s", base_types[*q - 'A']);
87 				while (array--)
88 					rlen += scnprintf(buf + rlen, maxlen - rlen, "[]");
89 				array = 0;
90 				narg++;
91 			} else
92 				buf[rlen++] = *q;
93 			break;
94 		case 'V':
95 			if (mode == MODE_TYPE) {
96 				rlen += scnprintf(buf + rlen, maxlen - rlen, "void");
97 				while (array--)
98 					rlen += scnprintf(buf + rlen, maxlen - rlen, "[]");
99 				array = 0;
100 			} else
101 				buf[rlen++] = *q;
102 			break;
103 		case '[':
104 			if (mode != MODE_TYPE)
105 				goto error;
106 			array++;
107 			break;
108 		case '(':
109 			if (mode != MODE_FUNC)
110 				goto error;
111 			buf[rlen++] = *q;
112 			mode = MODE_TYPE;
113 			break;
114 		case ')':
115 			if (mode != MODE_TYPE)
116 				goto error;
117 			buf[rlen++] = *q;
118 			narg = 0;
119 			break;
120 		case ';':
121 			if (mode != MODE_CLASS && mode != MODE_CTYPE)
122 				goto error;
123 			/* safe because at least one other char to process */
124 			if (isalpha(*(q + 1)) && mode == MODE_CLASS)
125 				rlen += scnprintf(buf + rlen, maxlen - rlen, ".");
126 			if (mode == MODE_CLASS)
127 				mode = MODE_FUNC;
128 			else if (mode == MODE_CTYPE)
129 				mode = MODE_TYPE;
130 			break;
131 		case '/':
132 			if (mode != MODE_CLASS && mode != MODE_CTYPE)
133 				goto error;
134 			rlen += scnprintf(buf + rlen, maxlen - rlen, ".");
135 			break;
136 		default :
137 			buf[rlen++] = *q;
138 		}
139 	}
140 	buf[rlen] = '\0';
141 	return buf;
142 error:
143 	return NULL;
144 }
145 
146 /*
147  * Demangle Java function signature (openJDK, not GCJ)
148  * input:
149  * 	str: string to parse. String is not modified
150  *    flags: combination of JAVA_DEMANGLE_* flags to modify demangling
151  * return:
152  *	if input can be demangled, then a newly allocated string is returned.
153  *	if input cannot be demangled, then NULL is returned
154  *
155  * Note: caller is responsible for freeing demangled string
156  */
157 char *
java_demangle_sym(const char * str,int flags)158 java_demangle_sym(const char *str, int flags)
159 {
160 	char *buf, *ptr;
161 	char *p;
162 	size_t len, l1 = 0;
163 
164 	if (!str)
165 		return NULL;
166 
167 	/* find start of return type */
168 	p = strrchr(str, ')');
169 	if (!p)
170 		return NULL;
171 
172 	/*
173 	 * expansion factor estimated to 3x
174 	 */
175 	len = strlen(str) * 3 + 1;
176 	buf = malloc(len);
177 	if (!buf)
178 		return NULL;
179 
180 	buf[0] = '\0';
181 	if (!(flags & JAVA_DEMANGLE_NORET)) {
182 		/*
183 		 * get return type first
184 		 */
185 		ptr = __demangle_java_sym(p + 1, NULL, buf, len, MODE_TYPE);
186 		if (!ptr)
187 			goto error;
188 
189 		/* add space between return type and function prototype */
190 		l1 = strlen(buf);
191 		buf[l1++] = ' ';
192 	}
193 
194 	/* process function up to return type */
195 	ptr = __demangle_java_sym(str, p + 1, buf + l1, len - l1, MODE_PREFIX);
196 	if (!ptr)
197 		goto error;
198 
199 	return buf;
200 error:
201 	free(buf);
202 	return NULL;
203 }
204