用c写了个后台扫描

/** * Notice: The program is not debug on internet and not use thread supervene. * date  : 6-26 * author: jker  **/#include <sys/socket.h>#include <stdio.h>#include <netinet/in.h>#include <string.h>#include <netdb.h>#include <sys/types.h>#include <sys/stat.h>#include <fcntl.h>#include <unistd.h>#include <stdlib.h>#define LINE 1024#define dict "dict.txt"#define result "manager.txt"void itos(int num,char *str){  int a=num;  int x,y,z;  x=a/100;  y=a%100/10;  z=a%10;  if(x==0){    if(y==0){      str[0]+=z;      str[1]='/0';    }else{      str[0]+=y;      str[1]+=z;      str[2]='/0';    }  }else{    str[0]+=x;    str[1]+=y;    str[2]+=z;    str[3]='/0';  }  return;}char *nip(char *oip){  char *str[4]={""},*rtn;  char *delim = ".";  char * tmp;  int i=0;  char arr[4]={48,48,48,'/0'};  rtn = malloc(512);  memset(rtn,'/0',512);  tmp = strtok(oip,delim);  str[i++]=tmp;  while(tmp=strtok(NULL,delim)){    str[i++]=tmp;  }  for(i=3;i>=0;i--){    if(atoi(str[i])<255){      itos(atoi(str[i])+1,arr);      str[i]=arr;      break;    }  }  for(i=0;i<4;i++){    strcat(rtn,str[i]);    if(i<3)strcat(rtn,delim);  }  return rtn;}int main(int argc,char *argv[]){  int sc,fd;  unsigned short port = 80;  struct sockaddr_in add;  char *ip,*sip,*eip;  struct hostent *host;  char rheader[LINE],dictbuf[LINE],resbuf[LINE];  char *dir,path[LINE]="",*arr[LINE],*tmp,state[3],manager[LINE];  int i=0,n=0,bytes;  if(argc != 3){    printf("please input startIp and endIp./r/n");    return -1;  }  dir = get_current_dir_name();  strcat(path,dir);  strcat(path,"/");  strcat(path,dict);  fd = open(path,O_RDONLY);  read(fd,dictbuf,sizeof(dictbuf));  close(fd);  arr[n++]=strtok(dictbuf,"/r/n");  while(tmp=strtok(NULL,"/r/n"))arr[n++]=tmp;  ip = malloc(512);  memset(ip,'/0',512);  sip = argv[1];  eip = argv[2];  strcpy(ip,sip);  memset(manager,'/0',LINE);  memset(rheader,'/0',LINE);  sc = socket(AF_INET,SOCK_STREAM,0);  if(sc == -1){    printf("create socket fail!/r/n");    return -1;  }  printf("create socket ok./r/n");  bzero(&add,sizeof(add));  add.sin_family=AF_INET;  add.sin_port=htons(port);  bzero(&path,sizeof(path));  strcat(path,dir);  strcat(path,"/");  strcat(path,result);  fd = open(path,O_WRONLY|O_CREAT);  do{    host = gethostbyaddr(ip,strlen(ip),AF_INET);    if(host == (struct hostent *)NULL) {      printf("can`t get host from %s/r/n",ip);      if(strcmp(ip,eip)<0)ip=nip(ip);      continue;    }else{                                                                                    printf("host name:%s/n",host->h_name);    }    add.sin_addr.s_addr=inet_addr(ip);    if(connect(sc,(struct sockaddr *)(&add),sizeof(struct sockaddr))==-1){      printf("conn fail!/r/n");      return -1;    }    for(;i<n;i++){      strcat(rheader,"HEAD ");      strcat(rheader,arr[i]);      strcat(rheader," HTTP/1.1");      strcat(rheader,"/r/n");      strcat(rheader,"Host:");      strcat(rheader,host->h_name);      strcat(rheader,"/r/n");      //strcat(rheader,"Accept:*//*");      //strcat(rheader,"/r/n");      strcat(rheader,"Connection:Keep-Alive");      strcat(rheader,"/r/n");      write(sc, rheader, strlen(rheader));usleep(100);              bytes = read(sc, resbuf, LINE);              printf("Response from %s:/n",ip);              write(STDOUT_FILENO, resbuf, bytes);      for(i=0;i<3;i++){        state[i]=resbuf[i+9];      }      if(!((state>="400" && state<="450")||state=="500")){        strcat(manager,"http://");        strcat(manager,host->h_name);        strcat(manager,arr[i]);        strcat(manager,"/r/n");   write(fd,manager,sizeof(manager));      }    }     close(sc);    ip = nip(ip);  }while(strcmp(ip,eip)<0);  close(fd);  return 0;}