大神急救！！！！输入进程号pid，输出进程名pname。运行出现段错误，调试了很久，只想说这是有史以来遇到的最纠结的段错误，莫名其妙！
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <sys/types.h>


void getProcessName(int pid, char *pname)
{
  //get process name by shell
  char cmd[100]={0};
   
  sprintf(cmd,"readlink /proc/%d/exe >/pname.txt",pid);
  system(cmd);

  sleep(2);
   
  //open file
  int fd=open("/pname.txt" ,O_RDWR);
  printf("#####%d\n",fd);
  if(fd<0)
  {
  printf("open():\n");
  return;
  }
printf("!!!!!");

  //read file  
  if(read(fd,pname,200)<0)
  {
  perror("read():\n");
  return;
  }
   
   
  //close file
  if(close(fd)<0)
  {
  perror("close():");
  return;
  }
  //remove file
  system("rm /pname.txt");
}

void main(){
int pid;
char chs[200];
printf("Please input pid: \n");
scanf("%d",pid);
getProcessName(pid, chs);
if(chs)
printf("The name of pid%d is %s: ", pid ,chs);
}

------解决方案--------------------
要学会gdb啊 定位段错误几秒钟的事

scanf("%d",pid);