C 语言执行机器码指令

#include <stdio.h>  
#include <string.h>  
#include <sys/mman.h>

int main() {    
    typedef int (*func_t)();
    unsigned char code[] = {
        0xb8, 0x08, 0x00, 0x00, 0x00,  // mov eax, 0x08
        0xc3  // ret
    };

    // 申请一片可读可写可执行的匿名私有内存区域
    unsigned char *pcode = (unsigned char *)mmap(
                NULL, 4096, PROT_READ | PROT_WRITE | PROT_EXEC,
                MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
    memcpy(pcode, code, sizeof(code));

    func_t foo = pcode;
    printf("%d\n", foo());

    munmap(pcode, 4096);
    return 0;    
}