[PoC, C] Get CPU hardware vendor.

poc_cpuid-vendor.c

#include <stdio.h>

static inline void
cpuid_vendor(char *vendor) __attribute__((always_inline));
void cpuid_write(char *);

int main(void)
{
  char cpu_vendor[13];
  cpuid_write(cpu_vendor);
  printf("[+] CPU: %s\n", cpu_vendor);

  return 0;
}

void cpuid_write(char *vendor)
{
  cpuid_vendor(vendor);
}

static inline void cpuid_vendor(char *vendor)
{
  __uint32_t ebx = 0, ecx = 0, edx = 0;

  __asm__ __volatile__("cpuid"      \
  		      : "=b"(ebx),  \
		      "=c"(ecx),    \
		      "=d"(edx)     \
		      : "a"(0x00));

  sprintf(vendor,   "%c%c%c%c", ebx, (ebx >> 0x08), (ebx >> 0x10), (ebx >> 0x18));
  sprintf(vendor+4, "%c%c%c%c", edx, (edx >> 0x08), (edx >> 0x10), (edx >> 0x18));
  sprintf(vendor+8, "%c%c%c%c", ecx, (ecx >> 0x08), (ecx >> 0x10), (ecx >> 0x18));

  vendor[12] = 0x00;
}