test_customized_mnem.c

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/* Capstone Disassembly Engine */
/* By Nguyen Anh Quynh <aquynh@gmail.com>, 2015-2019 */
 
// This sample code demonstrates the option CS_OPT_MNEMONIC
// to customize instruction mnemonic.
 
#include <stdio.h>
#include <stdlib.h>
 
#include <capstone/platform.h>
#include <capstone/capstone.h>
 
#define X86_CODE32 "\x75\x01"
 
// Print out the input code in hexadecimal format
static void print_string_hex(unsigned char *str, size_t len)
{
    unsigned char *c;
 
    for (c = str; c < str + len; c++) {
        printf("%02x ", *c & 0xff);
    }
    printf("\t");
}
 
// Print one instruction
static void print_insn(csh handle)
{
    cs_insn *insn;
    size_t count;
    
    count = cs_disasm(handle, (const uint8_t *)X86_CODE32, sizeof(X86_CODE32) - 1, 0x1000, 1, &insn);
    if (count) {
        print_string_hex((unsigned char *)X86_CODE32, sizeof(X86_CODE32) - 1);
        printf("\t%s\t%s\n", insn[0].mnemonic, insn[0].op_str); 
        // Free memory allocated by cs_disasm()
        cs_free(insn, count);
    } else {
        printf("ERROR: Failed to disasm given code!\n");
        abort();
    }
}
 
static void test()
{
    csh handle;
    cs_err err;
    // Customize mnemonic JNE to "jnz"
    cs_opt_mnem my_mnem = { X86_INS_JNE, "jnz" };
    // Set .mnemonic to NULL to reset to default mnemonic
    cs_opt_mnem default_mnem = { X86_INS_JNE, NULL };
 
    err = cs_open(CS_ARCH_X86, CS_MODE_32, &handle);
    if (err) {
        printf("Failed on cs_open() with error returned: %u\n", err);
        abort();
    }
 
    // 1. Print out the instruction in default setup.
    printf("Disassemble X86 code with default instruction mnemonic\n");
    print_insn(handle);
 
    // Customized mnemonic JNE to JNZ using CS_OPT_MNEMONIC option
    printf("\nNow customize engine to change mnemonic from 'JNE' to 'JNZ'\n");
    cs_option(handle, CS_OPT_MNEMONIC, (size_t)&my_mnem);
 
    // 2. Now print out the instruction in newly customized setup.
    print_insn(handle);
 
    // Reset engine to use the default mnemonic of JNE
    printf("\nReset engine to use the default mnemonic\n");
    cs_option(handle, CS_OPT_MNEMONIC, (size_t)&default_mnem);
 
    // 3. Now print out the instruction in default setup.
    print_insn(handle);
 
    // Done
    cs_close(&handle);
}
 
int main()
{
    test();
 
    return 0;
}