WebBench源码剖析（下）

上一篇文章对webBench压力测试工具中的Socket.c文件中的代码进行了详细的解析，接下来在这篇文章中我将会对webbench.c文件中的源码进行分析。如果分析过程中什么地方有误，希望大家指出来，谢谢！

webbench.c源码

#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>//结构体sigaction所在的头文件

/* values */
volatile int timerexpired=0;
int speed=0;
int failed=0;
int bytes=0;

/* 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; //默认情况下使用http中的GET方法发送请求。可以在命令行输入使用其他方法，如--head
int clients=1; //默认并发数为1，也就是fork出的子进程个数,可以由命令行参数-c指定
int force=0;
int force_reload=0;
int proxyport=80; //服务的端口号
char *proxyhost=NULL; //目的主机
int benchtime=30; //测试时间 默认为30秒 可由命令行参数-t指定

/* internal */
int mypipe[2]; //建立管道时使用，mypipe[0]是读取管道的文件描述符，mypipe[1]是向管道中写的文件描述符
char host[MAXHOSTNAMELEN]; //定义服务器IP
#define REQUEST_SIZE 2048
char request[REQUEST_SIZE]; //存放一个HTTP请求的信息，默认情况下使用请求GET方法

static const struct option long_options[]=//由结构体option构成的数组
{
{"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}
};

webben.c文件中包含以下函数：

(1)int main(int argc, char *argv[]);
(2)void usage();
(3)static void build_request(const char *url);
(4)static int bench(void);
(5)int Socket(const char *host, int clientPort);
(6)static void benchcore(const char* host,const int port, const char *request);
(7)static void alarm_handler(int signal);main函数为程序入口函数，我们从main开始分析代码：
（1）main函数

int main(int argc, char *argv[])
{
int opt=0;
int options_index=0;
char *tmp=NULL;

if(argc==1)//仅仅输入一个参数时
{
usage();//命令行提示
return 2;
}

//使用getopt_long函数对命令行参数进行解析，初始化配置
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,':');//strrchr(char *str, char c)找出 str 中最后一次出现的字符 c 的地址，然后将该地址返回。
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;
}
}

if(optind==argc) {//命令行输入错误，会使用usage函数来提示用户正确的输入方法
fprintf(stderr,"webbench: Missing URL!\n");
usage();
return 2;
}

if(clients==0) clients=1;
if(benchtime==0) benchtime=30;

/* Copyright */
fprintf(stderr,"Webbench - Simple Web Benchmark "PROGRAM_VERSION"\n"
"Copyright (c) Radim Kolar 1997-2004, GPL Open Source Software.\n"
);

//根据用户的输入的url，构造http请求报文放入全局变量request中（request）
build_request(argv[optind]);//（argv[optind]是命令行参数的最后一个参数，是目的主机的url）

printf("Runing info: ");

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");
return bench();
}mian函数的功能是对命令行参数进行解析，如果命令行输入错误，调用usage函数提示用户输入；如果正确，根据解析结果调用build_request函数建立一个http请求。然后调用bench函数进行测试。
（2）usage函数

/*运行改程序时，如果输入错误的提示*/
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"
);
}
（3）build_request函数

/*根据url创建一个http请求，将请求放入全局变量char request[REQUEST_SIZE]*/
void build_request(const char *url)
{
char tmp[10];
int i;

//bzero(host,MAXHOSTNAMELEN);
//bzero(request,REQUEST_SIZE);
memset(host,0,MAXHOSTNAMELEN);
memset(request,0,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)//method是所要创建的http请求的类型，GET，PUSH，POST，HEAD，TRACE
{
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 (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;

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);
memset(tmp,0,10);
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;//设定端口号
}
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("\nRequest:\n%s\n",request);
}根据参数行命令建立一个Http请求，并将http请求放入到全局数据request中。

（4）bench函数

/*（1）首先测试TCP连接是否合法；
（2）调用pipe建立管道；
（3）调用fork创建子进程（父子进程共享文件），对每个子进程调用benchcore函数；
（4）将每个子进程的测试数据写入到管道中；
（5）父进程读取管道中的内容，并做汇总；
*/
static int bench(void)
{
int i,j,k;
pid_t pid=0;//进程描述符
FILE *f;

/*创建一个TCP连接，然后立马用close关闭该连接。只是用于测试是否可以正常建立连接到目的主机*/
i=Socket(proxyhost == NULL ? host : proxyhost, proxyport);//建立TCP连接
if(i<0) { //连接建立失败
fprintf(stderr,"\nConnect to server failed. Aborting benchmark.\n");
return 1;
}
close(i);//关闭该文件

/*创建管道*/
if(pipe(mypipe))
{
perror("pipe failed.");
return 3;
}

/* 使用fork系统调用创建子进程，父进程和子进程是共享文件的，因此他们共享同一个管道*/
for(i=0;i<clients;i++)
{
pid=fork();
if(pid <= (pid_t) 0)//说明是在子进程中或者创建进程出错了
{
sleep(1); /* make childs faster */
break;
}
}

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

//在每个子进程中调用benchcore函数，创建TCP连接，将数据写入管道中
if(pid == (pid_t) 0)
{
if(proxyhost == NULL)
benchcore(host,proxyport,request);//对每个子进程进行测试
else
benchcore(proxyhost,proxyport,request);

/* write results to pipe */
f=fdopen(mypipe[1],"w");//只用于打开管道，返回一个文件描述符
if(f==NULL)
{
perror("open pipe for writing failed.");
return 3;
}
fprintf(f,"%d %d %d\n",speed,failed,bytes);//往管道中写数据
fclose(f);

return 0;
}
else//父进程读取管道中的内容
{
f=fdopen(mypipe[0],"r");//打开管道，并返回一个标示读取的文件句柄
if(f==NULL)
{
perror("open pipe for reading failed.");
return 3;
}

setvbuf(f,NULL,_IONBF,0);

speed=0;
failed=0;
bytes=0;

while(1)
{
pid=fscanf(f,"%d %d %d",&i,&j,&k);//从f标示文件描述符中读取数据
if(pid<2)
{
fprintf(stderr,"Some of our childrens died.\n");
break;
}
//将从管道中读取的数据统计到全局变量中
speed+=i;
failed+=j;
bytes+=k;

/* fprintf(stderr,"*Knock* %d %d read=%d\n",speed,failed,pid); */
if(--clients==0) break;
}

fclose(f);

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;
}

（5）benchcore函数
/*对http请求进行测试*/
void benchcore(const char *host,const int port,const char *req)
{
int rlen;
char buf[1500];
int s,i;
struct sigaction sa;

/* setup alarm signal handler */
sa.sa_handler = alarm_handler;
sa.sa_flags=0;
if(sigaction(SIGALRM,&sa,NULL))
{
exit(3);
}
alarm(benchtime); // after benchtime,then exit

rlen=strlen(req);
nexttry:while(1)
{
if(timerexpired)//超时
{
if(failed>0)
{
/* fprintf(stderr,"Correcting failed by signal\n"); */
failed--;
}
return;
}

s=Socket(host,port);//使用host和port建立tcp连接
if(s<0) { failed++;continue;} //连接失败
if(rlen!=write(s,req,rlen))
{
failed++;
close(s);
continue;
}//将请求写入到套接字描述符所指代的socket中
if(http10==0)
{
if(shutdown(s,1))
{
failed++
;close(s);
continue;
}
}
if(force==0) //说明要等待服务器的响应
{
/* 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;}//关闭socket
speed++;
}
}

（6）alarm_handler函数
static void alarm_handler(int signal)
{
timerexpired=1;
}