webbench 源码阅读

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发布于: 2020 年 08 月 18 日
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﻿
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 (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：
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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，
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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。
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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）。
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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)
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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：
(2)信号相关API案例https://www.cnblogs.com/yxk529188712/p/4983565.html
(3)IO相关fwrite()
fread()
read()
(4)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。
3 执行流程 
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4 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
* 
*/ 
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#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>
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/* values */
volatile int timerexpired=0;
int speed=0;
int failed=0;
int bytes=0;
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/* 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;
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/* internal */
int mypipe[2];
char host[MAXHOSTNAMELEN];
#define REQUEST_SIZE 2048
char request[REQUEST_SIZE];
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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}
};
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/* prototypes */
static void benchcore(const char* host,const int port, const char *request);
static int bench(void);
static void build_request(const char *url);
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static void alarm_handler(int signal)
{
    timerexpired=1;
}    
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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"
           );
}
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int main(int argc, char *argv[])
{
    int opt=0;
    int options_index=0;
    char *tmp=NULL;
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    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;
        }
    }
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    if(optind==argc) {
        fprintf(stderr,"webbench: Missing URL!\n");
        usage();
        return 2;
    }
    //默认clients用户为1
    if(clients==0) 
        clients=1;
    //默认压测30s
    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"
            );
     //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");
    */
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    printf("Runing info: ");
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    if(clients==1) 
        printf("1 client");
    else
        printf("%d clients",clients);
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    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();
}
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//构造请求
void build_request(const char *url)
{
    char tmp[10];
    int i;
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    //bzero(host,MAXHOSTNAMELEN);
    //bzero(request,REQUEST_SIZE);
    memset(host,0,MAXHOSTNAMELEN);
    memset(request,0,REQUEST_SIZE);
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    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;
    }
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    strcat(request," ");
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    if(NULL==strstr(url,"://"))
    {
        fprintf(stderr, "\n%s: is not a valid URL.\n",url);
        exit(2);
    }
    //url限制大小为1500
    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;
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    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);
    }
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    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);
}
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/* vraci system rc error kod */
static int bench(void)
{
    int i,j,k;    
    pid_t pid=0;
    FILE *f;
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    /* 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;
    }
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    /* not needed, since we have alarm() in childrens */
    /* wait 4 next system clock tick */
    /*
    cas=time(NULL);
    while(time(NULL)==cas)
    sched_yield();
    */
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    /* 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;
        }
    }
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    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
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    if(pid == (pid_t) 0)
    {
        /* I am a child */
        if(proxyhost==NULL)
            benchcore(host,proxyport,request);
        else
            benchcore(proxyhost,proxyport,request);
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        /* 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);
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        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);
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        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;
}
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void benchcore(const char *host,const int port,const char *req)
{
    int rlen;
    char buf[1500];
    int s,i;
    struct sigaction sa;
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    /* 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
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    rlen=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;
                }
                else
                if(i==0) 
                    break;
                else
                    bytes+=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++;
    }
}
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