1 /* Capstone Disassembly Engine */
2 /* By Nguyen Anh Quynh <aquynh@gmail.com>, 2015-2019 */
3
4 // This sample code demonstrates the option CS_OPT_MNEMONIC
5 // to customize instruction mnemonic.
6
7 #include <stdio.h>
8 #include <stdlib.h>
9
10 #include <capstone/platform.h>
11 #include <capstone/capstone.h>
12
13 #define X86_CODE32 "\x75\x01"
14
15 // Print out the input code in hexadecimal format
print_string_hex(unsigned char * str,size_t len)16 static void print_string_hex(unsigned char *str, size_t len)
17 {
18 unsigned char *c;
19
20 for (c = str; c < str + len; c++) {
21 printf("%02x ", *c & 0xff);
22 }
23 printf("\t");
24 }
25
26 // Print one instruction
print_insn(csh handle)27 static void print_insn(csh handle)
28 {
29 cs_insn *insn;
30 size_t count;
31
32 count = cs_disasm(handle, (const uint8_t *)X86_CODE32, sizeof(X86_CODE32) - 1, 0x1000, 1, &insn);
33 if (count) {
34 print_string_hex((unsigned char *)X86_CODE32, sizeof(X86_CODE32) - 1);
35 printf("\t%s\t%s\n", insn[0].mnemonic, insn[0].op_str);
36 // Free memory allocated by cs_disasm()
37 cs_free(insn, count);
38 } else {
39 printf("ERROR: Failed to disasm given code!\n");
40 abort();
41 }
42 }
43
test()44 static void test()
45 {
46 csh handle;
47 cs_err err;
48 // Customize mnemonic JNE to "jnz"
49 cs_opt_mnem my_mnem = { X86_INS_JNE, "jnz" };
50 // Set .mnemonic to NULL to reset to default mnemonic
51 cs_opt_mnem default_mnem = { X86_INS_JNE, NULL };
52
53 err = cs_open(CS_ARCH_X86, CS_MODE_32, &handle);
54 if (err) {
55 printf("Failed on cs_open() with error returned: %u\n", err);
56 abort();
57 }
58
59 // 1. Print out the instruction in default setup.
60 printf("Disassemble X86 code with default instruction mnemonic\n");
61 print_insn(handle);
62
63 // Customized mnemonic JNE to JNZ using CS_OPT_MNEMONIC option
64 printf("\nNow customize engine to change mnemonic from 'JNE' to 'JNZ'\n");
65 cs_option(handle, CS_OPT_MNEMONIC, (size_t)&my_mnem);
66
67 // 2. Now print out the instruction in newly customized setup.
68 print_insn(handle);
69
70 // Reset engine to use the default mnemonic of JNE
71 printf("\nReset engine to use the default mnemonic\n");
72 cs_option(handle, CS_OPT_MNEMONIC, (size_t)&default_mnem);
73
74 // 3. Now print out the instruction in default setup.
75 print_insn(handle);
76
77 // Done
78 cs_close(&handle);
79 }
80
main()81 int main()
82 {
83 test();
84
85 return 0;
86 }
87