用户读取配置文件例程

用C读取用户配置文件.conf的两个示例
最近研究如何在linux上写个简单易用的802.1x client ，所以研究了一些c代码

发现这两个代码蛮有用的，以后如果写要读文件的程序可以参考一下了

一
static void setConfig(void)
{
   FILE  *fp;
   char   buf[4096];
   char  *p;
   int   i,len;
   static char name[32];
   static char password[32];
   static char nic[32];
   static char fakeAddress[32];
   int  intelligentReconnect=-1;
   int  echoInterval=-1;
   int  authenticationMode=-1;

   //the check and anylysis against Dot1xClient.conf  *don't*  work perfectly.
   //this may be improved in the later version.
   if( (fp=fopen("Dot1xClient.conf","r"))==NULL )
    err_quit("cannot open file Dot1xClient.conf ! check it.\n");
   while(fgets(buf,sizeof(buf),fp)!=NULL)//fgets遇到换行或EOF会结束
     {
         if( (buf[0]=='#') || (buf[0]=='\n') )
        continue;//继续下一循环
         len=strlen(buf);
         if(buf[len-1]=='\n')
        buf[len-1]='\0';//in order to form a string
         if( ( (p=strchr(buf,'=')) == NULL) || (p==buf) )//if not find =
        continue;
         //the code above doesn't detect ALL the errors!! it should be improved in future.

         *p='\0';//break the string into 2 parts.
    p++;//p ponit to the value now

         for(i=0; i        buf[i]=tolower(buf[i]);
   
         if(strcmp(buf,"name")==0)
            {  strncpy(name,p,sizeof(name)-1); //char *strncpy(char *dest, const char *src, size_t n);
        name[sizeof(name)-1]=0;
        m_name=name;
    }
         else if(strcmp(buf,"password")==0)
            {
              strncpy(password,p,sizeof(password)-1); password[sizeof(password)-1]=0;
              m_password=password;
             }
         else if(strcmp(buf,"authenticationmode")==0)
            { authenticationMode=atoi(p);  
        m_authenticationMode=authenticationMode; }
         else if(strcmp(buf,"nic")==0)
            {
               for(i=0; i               strncpy(nic,p,sizeof(nic)-1); nic[sizeof(nic)-1]=0; m_nic=nic;
             }
         else if(strcmp(buf,"echointerval")==0)
                 { echoInterval=atoi(p);   m_echoInterval=echoInterval;  }
         else if(strcmp(buf,"intelligentreconnect")==0)
                 { intelligentReconnect=atoi(p);  m_intelligentReconnect=intelligentReconnect; }
         else if(strcmp(buf,"fakeaddress")==0)
                {
                      strncpy(fakeAddress,p,sizeof(fakeAddress)-1);
                      fakeAddress[sizeof(fakeAddress)-1]=0;
                      if( inet_pton(AF_INET,fakeAddress,m_ip)<=0 )
                         err_msg("invalid fakeAddress found in Dot1xClient.conf, ignored...\n");
                      else m_fakeAddress=fakeAddress;
                }
         else continue;
     }
   if(ferror(fp)) err_quit("cannot read Dot1xClient.conf ! check it.\n");
   fclose(fp);

   if((m_name==NULL)||(m_name[0]==0)) err_quit("invalid name found in Dot1xClient.conf!\n");
   if((m_password==NULL)||(m_password[0]==0)) err_quit("invalid password found in Dot1xClient.conf!\n");
   if((m_authenticationMode<0)||(m_authenticationMode>1))
           err_quit("invalid authenticationMode found in Dot1xClient.conf!\n");
   if( (m_nic==NULL) || (strcmp(m_nic,"")==0) ||  (strcmp(m_nic,"any")==0) )
       err_quit("invalid nic found in Dot1xClient.conf!\n");
   if((m_echoInterval<0)||(m_echoInterval>100))
      err_quit("invalid echo interval found in Dot1xClient.conf!\n" );
   if((m_intelligentReconnect<0)||(m_intelligentReconnect>1))
      err_quit("invalid intelligentReconnect found in Dot1xClient.conf!\n");

   /*printf("m_name=%s\n",m_name);
   printf("m_password=%s\n",m_password);
   printf("m_nic=%s\n",m_nic);
   printf("m_authenticationMode=%d\n",m_authenticationMode);
   printf("m_echoInterval=%d\n",m_echoInterval);
   printf("m_intelligentReconnect=%d\n",m_intelligentReconnect);//NOT supported now!!
   printf("m_fakeAddress=%s\n",m_fakeAddress); */

   //just set them to zero since they don't seem to be important.
   memset(m_netgate,0,sizeof(m_netgate));  memset(m_dns1,0,sizeof(m_dns1));
}

二
void checkconfig()
{
    char line[100];
    printf("checking user config...\n");
  
    while(fgets(line,100,file))
    {
        line[strlen(line)-1]='\0';//add a flag of string end
        if(!memcmp("username",line,strlen("username")))//if find username
        {
            memcpy(usrData.username,(line+sizeof("username")),sizeof(usrData.username));
            printf("%s\n",usrData.username);
            continue;
        }
        if(!memcmp("password",line,strlen("password")))
        {
            memcpy(usrData.password,(line+sizeof("password")),sizeof(usrData.password));
            printf("********\n");
            continue;
        }
        if(!memcmp("Ip",line,strlen("Ip")))
        {
            memcpy(usrData.Ip,(unsigned char *)(line+sizeof("Ip")),sizeof(usrData.Ip));
            sprintf(strIP,"%d.%d.%d.%d",usrData.Ip[0],usrData.Ip[1],usrData.Ip[2],usrData.Ip[3]);//先格式化一下字符窜
            printf("%s\n",strIP);
            continue;
        }
        if(!memcmp("Mac",line,strlen("Mac")))
        {
            memcpy(usrData.Mac,(unsigned char *)(line+sizeof("Mac")),sizeof(usrData.Mac));
            printf("%02x-%02x-%02x-%02x-%02x-%02x\n",usrData.Mac[0],usrData.Mac[1],
                usrData.Mac[2],usrData.Mac[3],usrData.Mac[4],usrData.Mac[5]);
            continue;
        }
        if(!memcmp("nic",line,strlen("nic")))
        {
            memcpy(usrData.nic,(line+sizeof("nic")),sizeof(usrData.nic));
            printf("%s\n",usrData.nic);
            break;
        }
    }
    fclose(file);
}

void writeconfig()
{      
    file=fopen("dot1xClient.conf","w");
    fputs("username=",file);
    fputs(usrData.username,file);
    fputs("\n",file);

    fputs("password=",file);
    fputs(usrData.password,file);
    fputs("\n",file);

    fputs("Ip=",file);
    fputc(usrData.Ip[0],file);
    fputc(usrData.Ip[1],file);
    fputc(usrData.Ip[2],file);
    fputc(usrData.Ip[3],file);
    fputs("\n",file);

    fputs("Mac=",file);
    fputc(usrData.Mac[0],file);
    fputc(usrData.Mac[1],file);
    fputc(usrData.Mac[2],file);
    fputc(usrData.Mac[3],file);
    fputc(usrData.Mac[4],file);
    fputc(usrData.Mac[5],file);
    fputs("\n",file);

    fputs("nic=",file);
        fputs(usrData.nic,file);
    fputs("\n",file);
    fclose(file);
}