unicorn/tests/unit/test_pc_change.c

// Test PC change during the callback. by Nguyen Anh Quynh, 2016
#include "unicorn_test.h"
#include <inttypes.h>

#define OK(x)   uc_assert_success(x)

/* Called before every test to set up a new instance */
static int setup32(void **state)
{
    uc_engine *uc;

    OK(uc_open(UC_ARCH_X86, UC_MODE_32, &uc));

    *state = uc;
    return 0;
}

/* Called after every test to clean up */
static int teardown(void **state)
{
    uc_engine *uc = *state;

    OK(uc_close(uc));

    *state = NULL;
    return 0;
}

/******************************************************************************/

static void test_code_hook(uc_engine *uc, uint64_t address, uint32_t size, void *user_data)
{
    uint8_t tmp[256];
    int32_t r_eip = 0x1000006;
    printf("instruction at 0x%"PRIx64": ", address);

    if (!uc_mem_read(uc, address, tmp, size)) {
        uint32_t i;

        for (i = 0; i < size; i++) {
            printf("0x%x ", tmp[i]);
        }
        printf("\n");
    }

    if (address == 0x1000003) {
        // change the PC to "inc EDX"
        uc_reg_write(uc, UC_X86_REG_EIP, &r_eip);
    }
}

static void test_pc_change(void **state)
{
    uc_engine *uc = *state;
    uc_hook trace1;
    int32_t r_ecx = 3, r_edx = 15;

#define BASEADDR    0x1000000

    uint64_t address = BASEADDR;
    const uint8_t code[] = {
        0x41,           // inc ECX @0x1000000
        0x41,           // inc ECX
        0x41,           // inc ECX
        0x41,           // inc ECX @0x1000003
        0x41,           // inc ECX
        0x41,           // inc ECX

        0x42,           // inc EDX @0x1000006
        0x42,           // inc EDX
    };

#undef BASEADDR

    // map 2MB memory for this emulation
    OK(uc_mem_map(uc, address, 2 * 1024 * 1024, UC_PROT_ALL));

    // write machine code to be emulated to memory
    OK(uc_mem_write(uc, address, code, sizeof(code)));

    uc_reg_write(uc, UC_X86_REG_ECX, &r_ecx);
    uc_reg_write(uc, UC_X86_REG_EDX, &r_edx);
    printf("ECX = %u, EDX = %u\n", r_ecx, r_edx);

    // trace all instructions
    OK(uc_hook_add(uc, &trace1, UC_HOOK_CODE, test_code_hook, NULL, (uint64_t)1, (uint64_t)0));

    OK(uc_emu_start(uc, address, address+sizeof(code), 0, 0));

    uc_reg_read(uc, UC_X86_REG_ECX, &r_ecx);
    uc_reg_read(uc, UC_X86_REG_EDX, &r_edx);

    printf("ECX = %u, EDX = %u\n", r_ecx, r_edx);
    assert_int_equal(r_ecx, 6);
    assert_int_equal(r_edx, 17);
}

int main(void)
{
    const struct CMUnitTest tests[] = {
        cmocka_unit_test_setup_teardown(test_pc_change, setup32, teardown),
    };
    return cmocka_run_group_tests(tests, NULL, NULL);
}