webbench学习源码

       深入学习一个语言或者想提升自己的编程水平，最好的办法就是学习优秀的源代码，一个意外的机会，接触到了webbench的源码，里面认认真真的看下去真是get到不少东西。webbench就是一个用纯C语言实现压测工具，思路很简单，主进程创建出多个子进程，让多个子进程去访问url，记录子进程访问该网页的情况，主进程和子进程之间采用管道通信，最后主进程汇总子进程的数据结果，就是这么简单。 在webbench源码中，有很多技巧值得学习，如何组织代码让代码精剪一目了然，如何巧妙的使用全局变量，而且大量的字符串处理函数strcpy，strstr，strncasecmp，strlen，strchr，index，strncpy，strcat，让你惊呼原来C语言其实可以这么写，就是自己见识的太少了，不知道怎么用C语言。

 这个是wenbench的源码

// webbench.c

#include "socket.c"
#include <unistd.h>
#include <sys/param.h>
#include <rpc/types.h>
#include <getopt.h>
#include <strings.h>
#include <time.h>
#include <signal.h>

/* values */
volatile int timerexpired=0;  //判断压测时长是否已经到达设定的时间
int speed=0;   //记录进程成功得到服务器响应的数量
int failed=0;  //记录失败的数量（speed表示成功数，failed表示失败数）
int bytes=0;   //记录进程成功读取的字节数
/* globals */
int http10=1; /* 0 - http/0.9, 1 - http/1.0, 2 - http/1.1 */
/* Allow: GET, HEAD, OPTIONS, TRACE */
#define METHOD_GET 0
#define METHOD_HEAD 1
#define METHOD_OPTIONS 2
#define METHOD_TRACE 3
#define PROGRAM_VERSION "1.5"
int method=METHOD_GET; //默认请求方式为GET，也支持HEAD、OPTIONS、TRACE
int clients=1; //并发数目，默认只有1个进程发请求，通过-c参数设置
int force=0; //是否需要等待读取从server返回的数据，0表示要等待读取
int force_reload=0; //是否使用缓存，1表示不缓存，0表示可以缓存页面
int proxyport=80; //代理服务器的端口
char *proxyhost=NULL; //代理服务器的ip
int benchtime=30; //压测时间，默认30秒，通过-t参数设置
/* internal */
int mypipe[2]; //使用管道进行父进程和子进程的通信
char host[MAXHOSTNAMELEN]; //服务器端ip
#define REQUEST_SIZE 2048
char request[REQUEST_SIZE]; //所要发送的http请求



// getopt_long（）中的参数
static const struct option long_options[]=
{
 {"force",no_argument,&force,1},
 {"reload",no_argument,&force_reload,1},
 {"time",required_argument,NULL,'t'},
 {"help",no_argument,NULL,'?'},
 {"http09",no_argument,NULL,'9'},
 {"http10",no_argument,NULL,'1'},
 {"http11",no_argument,NULL,'2'},
 {"get",no_argument,&method,METHOD_GET},
 {"head",no_argument,&method,METHOD_HEAD},
 {"options",no_argument,&method,METHOD_OPTIONS},
 {"trace",no_argument,&method,METHOD_TRACE},
 {"version",no_argument,NULL,'V'},
 {"proxy",required_argument,NULL,'p'},
 {"clients",required_argument,NULL,'c'},
 {NULL,0,NULL,0}
};

/* prototypes */
static void benchcore(const char* host,const int port, const char *request);
static int bench(void);
static void build_request(const char *url);


//  webbench通过signal信号控制程序结束，这就是信号处理函数
static void alarm_handler(int signal)
{
   timerexpired=1;
}	

static void usage(void)
{
   fprintf(stderr,
	"webbench [option]... URL\n"
	"  -f|--force               Don't wait for reply from server.\n"
	"  -r|--reload              Send reload request - Pragma: no-cache.\n"
	"  -t|--time <sec>          Run benchmark for <sec> seconds. Default 30.\n"
	"  -p|--proxy <server:port> Use proxy server for request.\n"
	"  -c|--clients <n>         Run <n> HTTP clients at once. Default one.\n"
	"  -9|--http09              Use HTTP/0.9 style requests.\n"
	"  -1|--http10              Use HTTP/1.0 protocol.\n"
	"  -2|--http11              Use HTTP/1.1 protocol.\n"
	"  --get                    Use GET request method.\n"
	"  --head                   Use HEAD request method.\n"
	"  --options                Use OPTIONS request method.\n"
	"  --trace                  Use TRACE request method.\n"
	"  -?|-h|--help             This information.\n"
	"  -V|--version             Display program version.\n"
	);
};
int main(int argc, char *argv[])
{
 int opt=0;
 int options_index=0;
 char *tmp=NULL;

 if(argc==1)
 {
	  usage();
          return 2;
 } 

 // getopt_long函数读取命令行参数
 while((opt=getopt_long(argc,argv,"912Vfrt:p:c:?h",long_options,&options_index))!=EOF )
 {
  switch(opt)
  {
   case  0 : break;
   case 'f': force=1;break;
   case 'r': force_reload=1;break; 
   case '9': http10=0;break;
   case '1': http10=1;break;
   case '2': http10=2;break;
   case 'V': printf(PROGRAM_VERSION"\n");exit(0);
   case 't': benchtime=atoi(optarg);break;	     
   case 'p': 
	     /* proxy server parsing server:port */
	     tmp=strrchr(optarg,':');
	     proxyhost=optarg;
	     if(tmp==NULL)
	     {
		     break;
	     }
	     if(tmp==optarg)
	     {
		     fprintf(stderr,"Error in option --proxy %s: Missing hostname.\n",optarg);
		     return 2;
	     }
	     if(tmp==optarg+strlen(optarg)-1)
	     {
		     fprintf(stderr,"Error in option --proxy %s Port number is missing.\n",optarg);
		     return 2;
	     }
	     *tmp='\0';
	     proxyport=atoi(tmp+1);break;
   case ':':
   case 'h':
   case '?': usage();return 2;break;
   case 'c': clients=atoi(optarg);break;
  }
 }
 
 //optind储存第一个不包含选项的命令行参数
 if(optind==argc) {
                      fprintf(stderr,"webbench: Missing URL!\n");
		      usage();
		      return 2;
                    }

 if(clients==0) clients=1;
 if(benchtime==0) benchtime=60;
 /* Copyright */
 fprintf(stderr,"Webbench - Simple Web Benchmark "PROGRAM_VERSION"\n"
	 "Copyright (c) Radim Kolar 1997-2004, GPL Open Source Software.\n"
	 );
 build_request(argv[optind]);
 /* print bench info */
 printf("\nBenchmarking: ");
 switch(method)
 {
	 case METHOD_GET:
	 default:
		 printf("GET");break;
	 case METHOD_OPTIONS:
		 printf("OPTIONS");break;
	 case METHOD_HEAD:
		 printf("HEAD");break;
	 case METHOD_TRACE:
		 printf("TRACE");break;
 }
 printf(" %s",argv[optind]);
 switch(http10)
 {
	 case 0: printf(" (using HTTP/0.9)");break;
	 case 2: printf(" (using HTTP/1.1)");break;
 }
 printf("\n");
 if(clients==1) printf("1 client");
 else
   printf("%d clients",clients);

 printf(", running %d sec", benchtime);
 if(force) printf(", early socket close");
 if(proxyhost!=NULL) printf(", via proxy server %s:%d",proxyhost,proxyport);
 if(force_reload) printf(", forcing reload");
 printf(".\n");

 // 所有的压测都在bench函数实现
 return bench();
}

// 这个函数主要操作全局变量char request[REQUEST_SIZE]，根据url填充http全局变量
void build_request(const char *url)
{
  char tmp[10];
  int i;

  bzero(host,MAXHOSTNAMELEN);
  bzero(request,REQUEST_SIZE);

  if(force_reload && proxyhost!=NULL && http10<1) http10=1;
  if(method==METHOD_HEAD && http10<1) http10=1;
  if(method==METHOD_OPTIONS && http10<2) http10=2;
  if(method==METHOD_TRACE && http10<2) http10=2;

  switch(method)
  {
	  default:
	  case METHOD_GET: strcpy(request,"GET");break;
	  case METHOD_HEAD: strcpy(request,"HEAD");break;
	  case METHOD_OPTIONS: strcpy(request,"OPTIONS");break;
	  case METHOD_TRACE: strcpy(request,"TRACE");break;
  }
		  
  strcat(request," ");

  if(NULL==strstr(url,"://"))
  {
	  fprintf(stderr, "\n%s: is not a valid URL.\n",url);
	  exit(2);
  }
  if(strlen(url)>1500)
  {
         fprintf(stderr,"URL is too long.\n");
	 exit(2);
  }
  if(proxyhost==NULL)
	   if (0!=strncasecmp("http://",url,7)) 
	   { fprintf(stderr,"\nOnly HTTP protocol is directly supported, set --proxy for others.\n");
             exit(2);
           }
  /* protocol/host delimiter */
  i=strstr(url,"://")-url+3;
  /* printf("%d\n",i); */

  if(strchr(url+i,'/')==NULL) {
                                fprintf(stderr,"\nInvalid URL syntax - hostname don't ends with '/'.\n");
                                exit(2);
                              }
  if(proxyhost==NULL)
  {
   /* get port from hostname */
   if(index(url+i,':')!=NULL &&
      index(url+i,':')<index(url+i,'/'))
   {
	   strncpy(host,url+i,strchr(url+i,':')-url-i);
	   bzero(tmp,10);
	   strncpy(tmp,index(url+i,':')+1,strchr(url+i,'/')-index(url+i,':')-1);
	   /* printf("tmp=%s\n",tmp); */
	   proxyport=atoi(tmp);
	   if(proxyport==0) proxyport=80;
   } else
   {
     strncpy(host,url+i,strcspn(url+i,"/"));
   }
   // printf("Host=%s\n",host);
   strcat(request+strlen(request),url+i+strcspn(url+i,"/"));
  } else
  {
   // printf("ProxyHost=%s\nProxyPort=%d\n",proxyhost,proxyport);
   strcat(request,url);
  }
  if(http10==1)
	  strcat(request," HTTP/1.0");
  else if (http10==2)
	  strcat(request," HTTP/1.1");
  strcat(request,"\r\n");
  if(http10>0)
	  strcat(request,"User-Agent: WebBench "PROGRAM_VERSION"\r\n");
  if(proxyhost==NULL && http10>0)
  {
	  strcat(request,"Host: ");
	  strcat(request,host);
	  strcat(request,"\r\n");
  }
  if(force_reload && proxyhost!=NULL)
  {
	  strcat(request,"Pragma: no-cache\r\n");
  }
  if(http10>1)
	  strcat(request,"Connection: close\r\n");
  /* add empty line at end */
  if(http10>0) strcat(request,"\r\n"); 
  // printf("Req=%s\n",request);
}

/* vraci system rc error kod */
static int bench(void)
{
  int i,j,k;	
  pid_t pid=0;
  FILE *f;

  /* check avaibility of target server */
  //调用了Socket.c文件中的函数int Socket(...)
  i=Socket(proxyhost==NULL?host:proxyhost,proxyport);
  if(i<0) { 
	   fprintf(stderr,"\nConnect to server failed. Aborting benchmark.\n");
           return 1;
         }
  close(i);
  /* create pipe */
  if(pipe(mypipe))
  {
	  perror("pipe failed.");
	  return 3;
  }

  /* not needed, since we have alarm() in childrens */
  /* wait 4 next system clock tick */
  /*
  cas=time(NULL);
  while(time(NULL)==cas)
        sched_yield();
  */

  /* fork childs */
  for(i=0;i<clients;i++)
  {
	   pid=fork();
	   if(pid <= (pid_t) 0)
	   {
		   /* child process or error*/
	           sleep(1); /* make childs faster */
		   break;
	   }
  }

  if( pid< (pid_t) 0)
  {
          fprintf(stderr,"problems forking worker no. %d\n",i);
	  perror("fork failed.");
	  return 3;
  }

  //如果是子进程，调用benchcore进行测试
  if(pid== (pid_t) 0)
  {
    /* I am a child */
    if(proxyhost==NULL)
      benchcore(host,proxyport,request);
         else
      benchcore(proxyhost,proxyport,request);

         /* write results to pipe */
	 f=fdopen(mypipe[1],"w");
	 if(f==NULL)
	 {
		 perror("open pipe for writing failed.");
		 return 3;
	 }
	 /* fprintf(stderr,"Child - %d %d\n",speed,failed); */
	 fprintf(f,"%d %d %d\n",speed,failed,bytes);
	 fclose(f);
	 return 0;
  } else //如果是父进程，则从管道读取子进程输出，并作汇总
  {
	  f=fdopen(mypipe[0],"r");
	  if(f==NULL) 
	  {
		  perror("open pipe for reading failed.");
		  return 3;
	  }
	  setvbuf(f,NULL,_IONBF,0);
	  speed=0;
          failed=0;
          bytes=0;

    //从管道读取数据，fscanf为阻塞式函数
	  while(1)
	  {
		  pid=fscanf(f,"%d %d %d",&i,&j,&k);
		  if(pid<2)
                  {
                       fprintf(stderr,"Some of our childrens died.\n");
                       break;
                  }
		  speed+=i;
		  failed+=j;
		  bytes+=k;
		  /* fprintf(stderr,"*Knock* %d %d read=%d\n",speed,failed,pid); */
      //这句用于记录已经读了多少个子进程的数据，读完就退出
		  if(--clients==0) break;
	  }
	  fclose(f);

  //最后将结果打印到屏幕上
  printf("\nSpeed=%d pages/min, %d bytes/sec.\nRequests: %d susceed, %d failed.\n",
		  (int)((speed+failed)/(benchtime/60.0f)),
		  (int)(bytes/(float)benchtime),
		  speed,
		  failed);
  }
  return i;
}

//benchcore是子进程进行压力测试的函数，被每个子进程调用
void benchcore(const char *host,const int port,const char *req)
{
 int rlen;
 char buf[1500]; //记录服务器响应请求所返回的数据
 int s,i;
 struct sigaction sa;

//设置alarm_handler为信号处理函数
 sa.sa_handler=alarm_handler; 
 sa.sa_flags=0;

 //超时会产生信号SIGALRM，用sa中的指定函数处理
 if(sigaction(SIGALRM,&sa,NULL))
    exit(3);
 
 //开始计时
 alarm(benchtime);

 rlen=strlen(req);
 nexttry:while(1)
 {
    if(timerexpired) //一旦超时则返回
    {
       if(failed>0)
       {
          /* fprintf(stderr,"Correcting failed by signal\n"); */
          failed--;
       }
       return;
    }
    s=Socket(host,port);  //调用Socket函数建立TCP连接                        
    if(s<0) { failed++;continue;} 
    if(rlen!=write(s,req,rlen)) {failed++;close(s);continue;} //发出请求
    if(http10==0) 
	    if(shutdown(s,1)) { failed++;close(s);continue;}
    if(force==0)   //全局变量force表示是否要等待服务器返回的数据
    {
            /* read all available data from socket */
	    while(1)
	    {
              if(timerexpired) break; 
	      i=read(s,buf,1500);
              /* fprintf(stderr,"%d\n",i); */
	      if(i<0) 
              { 
                 failed++;
                 close(s);
                 goto nexttry;
              }
	       else
		       if(i==0) break;
		       else
			       bytes+=i;
	    }
    }
    if(close(s)) {failed++;continue;}
    speed++;
 }
}

这个代码就是创建socket，看书上大段文字，真的不如看看源码怎么写

#include <sys/types.h>
#include <sys/socket.h>
#include <fcntl.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <sys/time.h>
#include <string.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>

int Socket(const char *host, int clientPort)
{
    int sock;
    unsigned long inaddr;
    struct sockaddr_in ad;
    struct hostent *hp;
    
    memset(&ad, 0, sizeof(ad));
    ad.sin_family = AF_INET;

    inaddr = inet_addr(host);
    if (inaddr != INADDR_NONE)
        memcpy(&ad.sin_addr, &inaddr, sizeof(inaddr));
    else
    {
        hp = gethostbyname(host);
        if (hp == NULL)
            return -1;
        memcpy(&ad.sin_addr, hp->h_addr, hp->h_length);
    }
    ad.sin_port = htons(clientPort);
    
    sock = socket(AF_INET, SOCK_STREAM, 0);
    if (sock < 0)
        return sock;
    if (connect(sock, (struct sockaddr *)&ad, sizeof(ad)) < 0)
        return -1;
    return sock;
}

webbench的源码下载网站

这篇文章有带图解释，挺好的

WebBench-1.5源码剖析