webbench源码阅读

学习内容

　　一共五百多行代码，其中包含了linux编程常用的API。可以通过学习源码，把不熟悉的API练习练习。

1 如何使用webbench

(1)查看参数帮助

(2)运行方法

即以上模拟30个客户端在30秒期间并发请求百度，结果如下：

每分钟平均有1532次请求连接，服务器每秒传输字节为4039230，在30秒期间请求连接成功为766次，失败0次。

2 源码常用函数练习

(1) 选项参数

int getopt_long(int argc, char * const argv[],const char *optstring, const struct option *longopts,int *longindex);

函数中的argc和argv通常直接从main()的两个参数传递而来。optsting是选项参数组成的字符串：

option结构数组，option结构称为长选项表，其声明如下：

struct option

{

const char *name;

int has_arg;

int *flag;

int val;

};

结构中的元素解释如下：

const char *name：选项名，前面没有短横线。譬如"help"、"verbose"之类。

int has_arg：描述长选项是否有选项参数，如果有，是哪种类型的参数，其值见下表: 符号常量数值

含义

no_argument 0 选项没有参数

required_argument 1 选项需要参数

optional_argument 2 选项参数是可选的

int *flag：

如果该指针为NULL，那么getopt_long返回val字段的值；

如果该指针不为NULL，那么会使得它所指向的结构填入val字段的值，同时getopt_long返回0 int val：

如果flag是NULL，那么val通常是个字符常量，如果短选项和长选项一致，那么该字符就应该与optstring中

字符串optstring可以下列元素:

1.单个字符，表示选项，

2.单个字符后接一个冒号：表示该选项后必须跟一个参数。参数紧跟在选项后或者以空格隔开。该参数的指针赋给optarg。

3 单个字符后跟两个冒号，表示该选项后可以有参数也可以没有参数。如果有参数，参数必须紧跟在选项后不能以空格隔开。该参数的指针赋给optarg。（这个特性是GNU的扩张）。

optstring是一个字符串，表示可以接受的参数。例如，"a:b:cd"，表示可以接受的参数是a,b,c,d，其中，a和b参数后面跟有更多的参数值。(例如：-a host --b name)

最后一个参数：longindex参数一般赋为NULL即可；如果没有设置为NULL，那么它就指向一个变量，这个变量会被赋值为寻找到的长选项在longopts中的索引值，这可以用于错误诊断。

函数使用方法：

View Code

(3)信号相关API

案例https://www.cnblogs.com/yxk529188712/p/4983565.html

(4)IO相关

fwrite()

fread()

read()

(5)管道

int pipe(int fd[2]) 成功返回0，失败返回-1

管道和有名管道是进程间通信机制之一

管道是半双工，所以双方通信需要建立两个通道

FILE * fdopen(int fildes,const char * mode);

fdopen取一个现存的文件描述符（我们可能从 o p e n , d u p , d u p 2 , f c n t l或p i p e函数得到此文件描述符），并使一个标准的I / O流与该描述符相结合。此函数常用于由创建管道和网络通信通道函数获得的描述符。因为这些特殊类型的文件不能用标准I/O fopen函数打开，首先必须先调用设备专用函数以获得一个文件描述符，然后用f d o p e n使一个标准I / O流与该描述符相结合。　　
fdopen()会将参数fildes 的文件描述符，转换为对应的文件指针后返回。参数mode 字符串　　则代表着文件指针的流形态，此形态必须和原先文件描述词读写模式相同。

View Code

2 执行流程

3 源码注释

/*
* (C) Radim Kolar 1997-2004
* This is free software, see GNU Public License version 2 for
* details.
*
* Simple forking WWW Server benchmark:
*
* Usage:
*   webbench --help
*
* Return codes:
*    0 - sucess
*    1 - benchmark failed (server is not on-line)
*    2 - bad param
*    3 - internal error, fork failed
*
*/ #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;
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;
int clients=1;
int force=0;
int force_reload=0;
int proxyport=80;
char *proxyhost=NULL;
int benchtime=30;/* internal */
int mypipe[2];
char host[MAXHOSTNAMELEN];
#define REQUEST_SIZE 2048
char request[REQUEST_SIZE];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);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 参数处理 根据不同的选项对应不同的操作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;}}if(optind==argc) {fprintf(stderr,"webbench: Missing URL!\n");usage();return 2;}//默认clients用户为1if(clients==0) clients=1;//默认压测30sif(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");//构造请求build_request(argv[optind]);// print request info ,do it in function build_request/*printf("Benchmarking: ");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");*/printf("Runing info: ");if(clients==1) printf("1 client");elseprintf("%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();
}//构造请求
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;//不同的构造头方法/*http头部格式请求方法 空格 URL 空格 协议版本 \r\n头部字段名    值    \r\n\r\n*/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);}//url限制大小为1500if(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;} 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");//到这里头部构造完成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);
}/* vraci system rc error kod */
static int bench(void)
{int i,j,k;    pid_t pid=0;FILE *f;/* check avaibility of target server */i=Socket(proxyhost==NULL?host:proxyhost,proxyport);if(i<0) { fprintf(stderr,"\nConnect to server failed. Aborting benchmark.\n");return 1;}close(i);/* 创建管道 */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 *///多少个用户多少个进程 fork一次返回两个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if(pid == (pid_t) 0){/* I am a child */if(proxyhost==NULL)benchcore(host,proxyport,request);elsebenchcore(proxyhost,proxyport,request);/* write results to pipe *///构造完请求得到结果写入管道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{//父进程从管道读数据f=fdopen(mypipe[0],"r");if(f==NULL) {perror("open pipe for reading failed.");return 3;}setvbuf(f,NULL,_IONBF,0);//不使用缓冲。每个 I/O 操作都被即时写入。buffer 和 size 参数被忽略speed=0;failed=0;bytes=0;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); */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;
}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 exitrlen=strlen(req);nexttry:while(1){if(timerexpired){if(failed>0){/* fprintf(stderr,"Correcting failed by signal\n"); */failed--;}return;}s=Socket(host,port); //尝试连接//失败次数统计if(s<0) {failed++;continue;} if(rlen!=write(s,req,rlen)) {failed++;close(s);continue;}if(http10==0) if(shutdown(s,1)) {failed++;close(s);continue;}if(force==0) {/* 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;}elseif(i==0) break;elsebytes+=i;//read返回的是字节数 所以在此可以统计字节数}}if(close(s)) {failed++;continue;}speed++;}
}