Webbench源码分析之参数输入getopt_long（一）

概述：最近想看一些优秀的开源项目，然后知乎上找到一个列表，说可以看看webbench源码，总共代码也就500多行。所以就开始看开源代码webbench，这也算是笔记吧。今天主要看了参数输入部分，所以就详细了解了getopt_long函数的使用方法。

webbench.c的源码

/** (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 2048char 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;    }     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;    }    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"            );    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");    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();}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)    {        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;        }         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);}/* 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);    /* 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;    }    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    {        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;        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 exit    rlen=strlen(req);    nexttry:while(1)    {        if(timerexpired)        {            if(failed>0)            {                /* fprintf(stderr,"Correcting failed by signal\n"); */                failed--;            }            return;        }        s=Socket(host,port);                                  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;            }        }        if(close(s)) {failed++;continue;}        speed++;    }}

参数输入部分解析
对于执行程序，我们经常有各种选项配置，比如我们使用webbench时，执行如下命令。

$ webbench -c 10 -t 20 http://www.baidu.com/

其中-c -t 就是选项，后面的10 20 就是对应的参数，今天看了源码，发现这些参数的输入识别都是通过getopt_long()函数进行解析的。因为之前也没用过，所以就详细的把这里看了，记录下来。

getopt_long()函数使用方法
1，函数定义

int getopt_long (int argc, char *const *argv, const char *shortopts, const struct option *longopts, int *indexptr)

2，各项参数解析
argc：int main(int argc, char *argv[])的argc的值。
argv：char *argv[] 中argv的值。
shortopts：我们定义的短选项的值，如我们输入的-t -c都属于短选项。这个短选项的定义规则如下：

如 char *shortopts = "abc:t:?h"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，表示该选项后必须跟一个参数。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。我们使用的webbench -c 10 -t 20 中c就是一个选项，10就是对应的参数，会赋值给optarg。

longopts：这就是对应的长选项的一个结构体了，比如我们输入webbench –get 像–get就属于长选项了。那我们首先看一下struct option结构体的定义。

struct option {    /*长选项名称*/    const char *name;      /*标志位，表示后面是否有参数。有三个参数可选，no_argument, required_argument 和 optional_argument.，分别表示无参数，必须后跟参数，参数可有可无*/    int has_arg;    /*一个int指针，若不为空，会将val值赋给*flag，函数返回值为0.若为空，函数返回val值*/          int *flag;    /*对应的长选项的值，通常是其对应的短选项字符*/    int val;};定义此结构体时最后一定要以0填充结束。webbench中的定义如下：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}};

indexptr：当我们使用的长选项时，我们可以通过这个返回的值，找出输入的对应长选项的名称。注意：此选项值只对输入的长选项有效。

3，注意事项

1，在我们使用getopt_long函数时，有两个参数optarg，optind。optarg容易理解，就是所对应选项的参数值，optind则是一个int型的数值，它则是代表第一个非定义选项的一个选项的位置，在后面的示例中详细说一下。2，使用getopt_long函数后，argv的排序会改变，后面例子详说。3，当输入选项与参数不对应，返回'?',在输入短选项时，shortopts起作用，当输入长选项时，longopts起作用。

webbench输入部分代码抠出来解析
下面是我抠出来的源代码，输入功能不变，只是单独拉出来，这样便于理解。

#include <getopt.h>#include <stdio.h>#include <stdlib.h>#include <string.h>/* 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;/*struct option一个结构体的定义赋值*/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}};/*各选项的具体解释及使用帮助信息*/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 (1 == argc) {    usage();    return -1;  }  while((opt=getopt_long(argc,argv,"912Vfrt:p:c:?h",long_options,&options_index))!=EOF )    {        /*打印getopt_long的返回值*/        if ( 0 != opt)          printf("opt = %c\n", opt);        switch(opt)        {            case  0 :              /*如果是长选项，options_index值对应long_options[options_index].name表示的              就是该长选项名称，因为这里长选项设置的都是flag指针不为空，所以都返回0*/              printf("opt-name = %s\n",long_options[options_index].name);              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':            /*optarg 对应选项的参数值*/            printf("case p:%s\n",optarg);            /* 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);            printf("server:%s,port:%d\n",proxyhost,proxyport);            break;            case ':':            case 'h':            case '?': usage();return 2;break;            case 'c': clients=atoi(optarg);break;        }    }    /*打印新的argv的排序*/    printf("new argv sort: ");    int i;    for (i = 1; i < argc ; i ++) {      printf("%s ", argv[i]);    }    printf("\n");    /*打印optind值及对应的选项值，optind指向的是第一个非定义参数的值*/    printf("optind = %d,argc = %d,optind_str = %s\n",optind, argc, argv[optind]);    if(optind==argc) {        fprintf(stderr,"webbench: Missing URL!\n");        usage();        return 2;    }    printf("url:%s\n",argv[optind]);  return 0;}

1，验证optind指向的是非定义选项的第一个选项值，且执行完getopt_long后argv会重新排序。执行如下指令。

$ ./getopt_long_test http://www.baidu.com/ -c 10 sky -t 20 

执行结果：

从结果中我们可以看到，argv输入的顺序，执行完后被重新排序了。同时optind对应的也是第一个非定义的选项中的第一个选项，如果我们把sky放在前面，那么输出就是sky。如图：

我们在使用webbench时最后加一个url地址，其实就是非定义选项的第一个，所以作者就是这样认为输入的是url。

2，验证optarg就是对应的输入参数，我们这里假设加上代理服务器参数。执行如下指令。

$ ./getopt_long_test -p 192.168.10.222:56  http://www.baidu.com/ 

执行结果如下：

可以看到我们输入的选项-p 对应的参数就是192.168.10.222:56。

3，验证输入长选项时，指针flag为空时返回val值，指针不为空时会赋值到flag并返回0值。

在我们的while循环后加上一句，之前也加上这一句。 printf("method = %d\n",method);

执行结果如下：

我们可以看到，验证成功，method本来是0，我们用了–head选项，程序就将METHOD_HEAD值赋给了method。同时我们用了–http10，返回了对应的值’1’.

总结：
这里主要就是先把第一部分选项参数输入的部分搞懂了，其实也就是getopt_long（）函数的使用，因为没有用过，所以才这么详细的看了，这样看别的源码，有类似内容就可以省略不看啦。这算是个序吧，未完待续……….Peace&Love！

参考官方文档地址：getopt_long()