WebBench是个比较简单的程序，只有两个源文件：webbench.c, socket.c。
对源码重新排版一下，方便阅读：
/*
* (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>
/*
* 超时标记，当被设置为 1 时，所有子进程退出
* volatile：
* - 让系统总是从内存读取数据，
* - 告诉编译器不要做任何优化，
* - 变量会在程序外被改变
*/
volatile int timerexpired=0;
/* 成功请求数 */
int speed = 0;
/* 失败请求数 */
int failed = 0;
/* 读取字节总数 */
int bytes = 0;
/* 支持的 HTTP 协议版本：0 - 0.9, 1 - 1.0, 2 - 1.1 */
int http10 = 1;
/* 支持的 HTTP 方法：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; /* 默认为GET方法 */
int clients = 1; /* 默认启动一个客户端（子进程） */
int force = 0; /* 是否等待响应数据返回，0 －等待，1 － 不等待 */
int force_reload = 0; /* 是否发送 Pragma: no-cache */
int proxyport = 80; /* 代理端口 */
char *proxyhost = NULL; /* 代理服务器名称 */
/*
* 执行时间，当子进程执行时间到过这个秒数之后，
* 发送 SIGALRM 信号，将 timerexpired 设置为 1，
* 让所有子进程退出
*/
int benchtime = 30;
/* 管道，子进程完成任务后，向写端写入数据，主进程从读端读取数据 */
int mypipe[2];
char host[MAXHOSTNAMELEN]; /* 主机名（64字节） */
#define REQUEST_SIZE 2048
char request[REQUEST_SIZE]; /* 请求字符串（HTTP头） */
/* 命令行的选项配置表，细节部分查看man文档：man getopt_long */
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}
};
/* 子进程执行请求任务的函数 */
static void benchcore(const char* host,const int port, const char *request);
/* 执行压测的主要入口函数 */
static int bench(void);
/* 生成 HTTP 头 */
static void build_request(const char *url);
/* 将 timerexpired 设置为1，让所有子进程退出 */
static void alarm_handler(int signal) {
timerexpired=1;
}
/* 打印帮助 */
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;
}
/* 参数解释，参见 man getopt_long */
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 = 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]); /* 最后一个非选项的参数，被视为URL */
/* 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");
return bench();
}
/* 生成 HTTP 头 */
void build_request (const char *url) {
char tmp[10];
int i;
bzero(host, MAXHOSTNAMELEN);
bzero(request, REQUEST_SIZE);
/* 协议适配
* */
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;
/* 测试远程主机是否能够连通 */
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();
*/
/* 生成子进程 */
for (i = 0; i < clients; i++) {
pid = fork();
if (pid <= (pid_t)0) {
/* child process or error*/
sleep(1); /* make childs faster */
/* 这个 break 很重要，它主要让子进程只能从父进程生成，
否则子进程会再生成子进程，子子孙孙很庞大的 */
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 */
/* 子进程执行请求：尽可能多的发送请求，直到超时返回为止 */
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); */
/* 将子进程执行任务的结果写入到管道中，以便父进程读取 */
fprintf(f, "%d %d %d\n", speed, failed, bytes);
fclose(f);
/* 子进程完成任务，返回退出 */
return 0;
} else {
/* 父进程读取管道，打印结果 */
printf("parent %d\n", getpid());
f = fdopen(mypipe[0], "r");
if (f == NULL) {
perror("open pipe for reading failed.");
return 3;
}
setvbuf(f, NULL, _IONBF, 0);
/* 虽然子进程不能污染父进程的这几个变量，但用前重置一下，在这里是个好习惯 */
speed = 0;
failed = 0;
bytes = 0;
/* 从管道中读取每个子进程的任务的执行情况，并计数 */
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); */
if (--clients == 0) {
break;
}
}
fclose(f);
/* 打印结果 */
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;
/* 这个是关键，当程序执行到指定的秒数之后，发送 SIGALRM 信号 */
sa.sa_handler = alarm_handler;
sa.sa_flags = 0;
if (sigaction(SIGALRM, &sa, NULL)) {
exit(3);
}
alarm(benchtime);
rlen = strlen(req);
/* 无限执行请求，直到接收到 SIGALRM 信号将 timerexpired 设置为 1 时 */
nexttry:
while (1) {
if (timerexpired) {
if (failed > 0) {
/* fprintf(stderr,"Correcting failed by signal\n"); */
failed--;
}
return;
}
/* 连接远程服务器 */
s = Socket(host, port);
if (s < 0) {
failed++;
continue;
}
/* 发送请求 */
if (rlen != write(s, req, rlen)) {
failed++;
close(s);
continue;
}
if (http10 == 0) {
/* 如果是 http/0.9 则关闭 socket 的写操作 */
if(shutdown(s, 1)) {
failed++;
close(s);
continue;
}
}
/* 如果等待响应数据返回，则读取响应数据，计算传输的字节数 */
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;
}
}
}
}
/* 关闭连接 */
if (close(s)) {
failed++;
continue;
}
/* 成功完成一次请求，并计数，继续下一次相同的请求，直到超时为止 */
speed++;
}
}下面是 socket.c，很简单，不再加注释，原样贴上：
/* $Id: socket.c 1.1 1995/01/01 07:11:14 cthuang Exp $
*
* This module has been modified by Radim Kolar for OS/2 emx
*/
/***********************************************************************
module: socket.c
program: popclient
SCCS ID: @(#)socket.c 1.5 4/1/94
programmer: Virginia Tech Computing Center
compiler: DEC RISC C compiler (Ultrix 4.1)
environment: DEC Ultrix 4.3
description: UNIX sockets code.
***********************************************************************/
#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;
}
来源：oschina
链接：https://my.oschina.net/u/159328/blog/341195