peek and poke for linux

peek.c

#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/mman.h>

int main(int argc,char **argv) {
   int devmem = -1;
   unsigned int addr = 0;
   unsigned int val = 0;
   unsigned char *buffer;
   if(argc<2) {
      printf("Usage: %s addr\n",argv[0]);
      return -1;
   }
   devmem = open("/dev/mem",O_RDWR);
   if(devmem<0) {
      printf("couldn't open /dev/mem. Are you root?\n");
      return -1;
   }
   sscanf(argv[1],"%x",&addr);
   buffer = mmap(0,65536,PROT_WRITE|PROT_READ,MAP_SHARED,devmem,addr&0xFFFF0000);
   if(!buffer) {
      close(devmem);
      return -1;
   }
   buffer += (addr&0x0000FFFF);
   val = *(unsigned int *)buffer;
   printf("%x\n",val);
   munmap(buffer&0xFFFF0000,1);
   close(devmem);
   return 0;
}

poke.c

#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/mman.h>

int main(int argc,char **argv) {
   int devmem = -1;
   unsigned int addr = 0;
   unsigned int val = 0;
   unsigned char *buffer;
   if(argc<3) {
      printf("Usage: %s addr val\n",argv[0]);
      return -1;
   }
   devmem = open("/dev/mem",O_RDWR);
   if(devmem<0) {
      printf("couldn't open /dev/mem. Are you root?\n");
      return -1;
   }
   sscanf(argv[1],"%x",&addr);
   sscanf(argv[2],"%x",&val);
   buffer = mmap(0,65536,PROT_WRITE|PROT_READ,MAP_SHARED,devmem,addr&0xFFFF0000);
   if(!buffer) {
      close(devmem);
      return -1;
   }
   buffer+=(addr&0x0000FFFF);
   *(unsigned int *)buffer = val;
   munmap(buffer&0xFFFF0000,1);
   close(devmem);
   return 0;
}