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myhttp.c
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#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <arpa/inet.h>
#include <sys/epoll.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/wait.h>
#define ISspace(x) isspace((int)(x))
#define SERVER_STRING "Server: crkhttp/0.1.0\r\n"
#define MAXNUM 2048
void error_occur(const char *str)
{
perror(str);
exit(EXIT_FAILURE); //EXIT_FAILURE需要stdlib
}
//创建并初始化监听套接字
int create_listenfd(int port)
{
int listenfd = 0;
listenfd = socket(AF_INET,SOCK_STREAM,0);
if(listenfd == -1)
error_occur("socket");
//设置端口复用
int opt = 1;
setsockopt(listenfd,SOL_SOCKET,SO_REUSEADDR,&opt,sizeof (opt));
//初始化地址结构
struct sockaddr_in addr;
addr.sin_addr.s_addr = htonl(INADDR_ANY);
addr.sin_family = AF_INET;
addr.sin_port = htons(port);
if(bind(listenfd,(struct sockaddr *)&addr,sizeof (addr)) < 0)
error_occur("bind");
if(listen(listenfd,5) < 0) //设置同一时刻建立连接的上限数
error_occur("listen");
return listenfd;
}
//处理连接请求
void do_accept(int httpfd,int epofd)
{
struct sockaddr_in addr;
socklen_t addr_len = sizeof (addr);
//接受连接请求并打印客户端地址信息
int cfd = 0; //socket for communication
cfd = accept(httpfd,(struct sockaddr *)&addr,&addr_len);
if(cfd == -1)
error_occur("accpet");
printf("New connection... IP: %s , Port: %d\n",inet_ntoa(addr.sin_addr),ntohs(addr.sin_port));
//epoll边缘触发模式
struct epoll_event temp;
temp.data.fd = cfd;
temp.events = EPOLLIN | EPOLLET;
//设置非阻塞
int flag = fcntl(cfd,F_GETFL);
flag |= O_NONBLOCK;
fcntl(cfd,F_SETFL,flag);
//插入
int res = epoll_ctl(epofd,EPOLL_CTL_ADD,cfd,&temp);
if(res == -1)
error_occur("epoll_ctl");
}
//断开连接时，关闭通信套接字并从epoll监听对象中移除
void disconnect(int cfd,int epofd)
{
int res = epoll_ctl(epofd,EPOLL_CTL_DEL,cfd,NULL);
if(res == -1)
error_occur("epoll_ctl for delete");
close(cfd);
}
//501没有相应实现（不支持的方法）
void unimplemented(int cfd)
{
char buf[1024];
sprintf(buf, "HTTP/1.0 501 Method Not Implemented\r\n");
send(cfd, buf, strlen(buf), 0);
sprintf(buf, SERVER_STRING);
send(cfd, buf, strlen(buf), 0);
sprintf(buf, "Content-Type: text/html\r\n");
send(cfd, buf, strlen(buf), 0);
sprintf(buf, "\r\n");
send(cfd, buf, strlen(buf), 0);
sprintf(buf, "<HTML><HEAD><TITLE>Method Not Implemented\r\n");
send(cfd, buf, strlen(buf), 0);
sprintf(buf, "</TITLE></HEAD>\r\n");
send(cfd, buf, strlen(buf), 0);
sprintf(buf, "<BODY><P>HTTP request method not supported.\r\n");
send(cfd, buf, strlen(buf), 0);
sprintf(buf, "</BODY></HTML>\r\n");
send(cfd, buf, strlen(buf), 0);
}
//400语法错误
void bad_request(int cfd)
{
char buf[1024];
//发送400
sprintf(buf, "HTTP/1.0 400 BAD REQUEST\r\n");
send(cfd, buf, sizeof(buf), 0);
sprintf(buf, "Content-type: text/html\r\n");
send(cfd, buf, sizeof(buf), 0);
sprintf(buf, "\r\n");
send(cfd, buf, sizeof(buf), 0);
sprintf(buf, "<P>Your browser sent a bad request, ");
send(cfd, buf, sizeof(buf), 0);
sprintf(buf, "such as a POST without a Content-Length.\r\n");
send(cfd, buf, sizeof(buf), 0);
}
//404页面错误
void not_found(int cfd)
{
char buf[1024];
sprintf(buf, "HTTP/1.0 404 NOT FOUND\r\n");
send(cfd, buf, strlen(buf), 0);
sprintf(buf, SERVER_STRING);
send(cfd, buf, strlen(buf), 0);
sprintf(buf, "Content-Type: text/html\r\n");
send(cfd, buf, strlen(buf), 0);
sprintf(buf, "\r\n");
send(cfd, buf, strlen(buf), 0);
sprintf(buf, "<HTML><TITLE>Not Found</TITLE>\r\n");
send(cfd, buf, strlen(buf), 0);
sprintf(buf, "<BODY><P>The server could not fulfill\r\n");
send(cfd, buf, strlen(buf), 0);
sprintf(buf, "your request because the resource specified\r\n");
send(cfd, buf, strlen(buf), 0);
sprintf(buf, "is unavailable or nonexistent.\r\n");
send(cfd, buf, strlen(buf), 0);
sprintf(buf, "</BODY></HTML>\r\n");
send(cfd, buf, strlen(buf), 0);
}
//500无法执行（属于服务器内部错误）
void cannot_execute(int cfd)
{
char buf[1024];
//发送500
sprintf(buf, "HTTP/1.0 500 Internal Server Error\r\n");
send(cfd, buf, strlen(buf), 0);
sprintf(buf, "Content-type: text/html\r\n");
send(cfd, buf, strlen(buf), 0);
sprintf(buf, "\r\n");
send(cfd, buf, strlen(buf), 0);
sprintf(buf, "<P>Error prohibited CGI execution.\r\n");
send(cfd, buf, strlen(buf), 0);
}
//读取一行http报文
int get_line(int sock, char *buf, int size)
{
int i = 0;
char c = '\0';
int n;
while ((i < size - 1) && (c != '\n'))
{
n = recv(sock, &c, 1, 0);
if (n > 0)
{
if (c == '\r')
{
n = recv(sock, &c, 1, MSG_PEEK);
if ((n > 0) && (c == '\n'))
recv(sock, &c, 1, 0);
else
c = '\n';
}
buf[i] = c;
i++;
}
else
c = '\n';
}
buf[i] = '\0';
return i;
}
//发送响应头部
void headers(int client, const char *filename)
{
char buf[1024];
(void)filename; // could use filename to determine file type 目前只支持text/html
//发送HTTP头
strcpy(buf, "HTTP/1.0 200 OK\r\n");
send(client, buf, strlen(buf), 0);
strcpy(buf, SERVER_STRING);
send(client, buf, strlen(buf), 0);
sprintf(buf,"Content-type: text/html\r\n");
send(client, buf, strlen(buf), 0);
strcpy(buf, "\r\n");
send(client, buf, strlen(buf), 0);
}
//读取文件
void cat(int cfd, FILE *resource)
{
//发送文件的内容
char buf[1024];
fgets(buf, sizeof(buf), resource);
while (!feof(resource))
{
send(cfd, buf, strlen(buf), 0);
fgets(buf, sizeof(buf), resource);
/*fget会覆盖buf之前的内容，而且短的能覆盖长的，相当于重写*/
}
}
//如果不是CGI文件，也就是静态文件，直接读取文件返回给请求的http客户端即可
void serve_file(int cfd, const char *filename)
{
FILE *resource = NULL;
int numchars = 1;
char buf[1024];
buf[0] = 'H'; //任意一个字符但不能是'\n'，确保进入下面循环
buf[1] = '\0'; //组成一个完整字符串与buf比较
while ((numchars > 0) && strcmp("\n", buf)) //读取丢弃缓冲区不需要的内容（请求头部）
numchars = get_line(cfd, buf, sizeof(buf));
//打开文件
resource = fopen(filename, "r");
if (resource == NULL)
not_found(cfd);
else
{
headers(cfd, filename);
cat(cfd, resource);
}
fclose(resource);//关闭文件句柄
}
void execute_cgi(int cfd, const char *path,const char *method, const char *query_string)
{
//printf("\n in founction execute cig\n");
char buf[1024];
int cgi_output[2];
int cgi_input[2];
pid_t pid;
int status;
int i;
char c;
int numchars = 1;
int content_length = -1;
//默认字符
buf[0] = 'A';
buf[1] = '\0';
if (strcasecmp(method, "GET") == 0)
while ((numchars > 0) && strcmp("\n", buf))
numchars = get_line(cfd, buf, sizeof(buf));
else
{
numchars = get_line(cfd, buf, sizeof(buf));
while ((numchars > 0) && strcmp("\n", buf))
{
buf[15] = '\0';
if (strcasecmp(buf, "Content-Length:") == 0)
content_length = atoi(&(buf[16]));
numchars = get_line(cfd, buf, sizeof(buf));
}
if (content_length == -1)
{
bad_request(cfd);
return;
}
}
sprintf(buf, "HTTP/1.0 200 OK\r\n");
send(cfd, buf, strlen(buf), 0);
if (pipe(cgi_output) < 0)
{
cannot_execute(cfd);
return;
}
if (pipe(cgi_input) < 0)
{
cannot_execute(cfd);
return;
}
if ( (pid = fork()) < 0 )
{
cannot_execute(cfd);
return;
}
if (pid == 0) /* 子进程: 运行CGI 脚本 */
{
char meth_env[255];
char query_env[255];
char length_env[255];
dup2(cgi_output[1], 1); //重定向标准输出到管道输出
dup2(cgi_input[0], 0); //重定向标准输入到管道输入
close(cgi_output[0]);//关闭了cgi_output中的读通道
close(cgi_input[1]);//关闭了cgi_input中的写通道
sprintf(meth_env, "REQUEST_METHOD=%s", method);
putenv(meth_env);
if (strcasecmp(method, "GET") == 0)
{
//存储QUERY_STRING
sprintf(query_env, "QUERY_STRING=%s", query_string);
fprintf(stderr,"query_string:%s query_env:%s\n",query_string,query_env);
putenv(query_env);
}
else
{ /* POST */
//存储CONTENT_LENGTH
sprintf(length_env, "CONTENT_LENGTH=%d", content_length);
putenv(length_env);
}
fprintf(stderr,"\n path: %s",path); //不能用printf，因为重定向了
execl(path, path, NULL);//执行CGI脚本
exit(0);
}
else
{
close(cgi_output[1]);
close(cgi_input[0]);
if (strcasecmp(method, "POST") == 0)
for (i = 0; i < content_length; i++)
{
recv(cfd, &c, 1, 0);
write(cgi_input[1], &c, 1);
}
//读取cgi脚本返回数据
while (read(cgi_output[0], &c, 1) > 0)//发送给浏览器
send(cfd, &c, 1, 0);
//运行结束关闭
close(cgi_output[0]);
close(cgi_input[1]);
waitpid(pid, &status, 0);
}
}
//读取并解析请求行
void do_read(int cfd,int epofd)
{
char buf[1024];
char method[255];
char url[255];
char protocol[12];
char path[512];
//size_t i, j;
struct stat st;
int cgi = 0;
char *query_string = NULL;
int len = get_line(cfd, buf, sizeof(buf));
if(len == 0)
{
printf("server disconnect...\n");
disconnect(cfd,epofd);
}
// i = 0;
// j = 0;
// while (!ISspace(buf[j]) && (i < sizeof(method) - 1))
// {
// //提取其中的请求方式
// method[i] = buf[j];
// i++;
// j++;
// }
// method[i] = '\0';
sscanf(buf,"%[^ ] %[^ ] %[^ ]",method,url,protocol); //正则表达式
//printf("method = %s, url = %s, protocol = %s\n",method,url,protocol);
//不支持的方法
if (strcasecmp(method, "GET") && strcasecmp(method, "POST")) //返回非0即true
{
unimplemented(cfd);
return;
}
if (strcasecmp(method, "POST") == 0)
cgi = 1;
if (strcasecmp(method, "GET") == 0)
{
query_string = url;
while ((*query_string != '?') && (*query_string != '\0'))
query_string++;
//如果有?说明有参数,使用cgi处理 */
if (*query_string == '?')
{
cgi = 1;
*query_string = '\0';
query_string++;
}
}
// i = 0;
// while (ISspace(buf[j]) && (j < sizeof(buf)))
// j++;
// while (!ISspace(buf[j]) && (i < sizeof(url) - 1) && (j < sizeof(buf)))
// {
// url[i] = buf[j];
// i++; j++;
// }
// url[i] = '\0';
sprintf(path, "httpdocs%s", url); //设置文件目录位置
//printf("path is :%s \n",path);
if (path[strlen(path) - 1] == '/') //路径是目录，则默认访问test页面
strcat(path, "test.html");
//根据路径获取文件状态，状态存在st结构体中
if (stat(path, &st) == -1) //获取不到文件状态（找不到文件）
{
while ((len > 0) && strcmp("\n", buf)) //读取并丢弃输入缓冲区剩余内容
{
//printf("return strcmp:%d\n",strcmp("\n", buf));
len = get_line(cfd, buf, sizeof(buf));
}
not_found(cfd);
}
else
{
//文件可执行
if ((st.st_mode & S_IXUSR) ||
(st.st_mode & S_IXGRP) ||
(st.st_mode & S_IXOTH))
//S_IXUSR:文件所有者具可执行权限
//S_IXGRP:用户组具可执行权限
//S_IXOTH:其他用户具可读取权限
cgi = 1;
if (!cgi)
serve_file(cfd, path);
else
execute_cgi(cfd, path, method, query_string);
}
disconnect(cfd,epofd);
printf("connection close...\n");
}
void epoll_run(int httpfd)
{
int epofd = 0;
epofd = epoll_create(MAXNUM); //创建epoll实例（红黑树根节点），返回句柄，MAXNUM为最大监听数的参考值，不够可以自动扩容
if(epofd == -1)
error_occur("epoll create");
struct epoll_event temp,event[MAXNUM];
temp.events = EPOLLIN; //构造监听套接字的节点
temp.data.fd = httpfd;
int res = epoll_ctl(epofd,EPOLL_CTL_ADD,httpfd,&temp); //插入监听套接字节点
if(res == -1)
error_occur("epoll_ctl");
int nready; //记录事件触发个数
for(;;)
{
nready = epoll_wait(epofd,event,MAXNUM,-1); //被触发的event被放入event数组,并返回触发个数
if(nready == -1)
error_occur("epoll_wait");
for(int i = 0;i < nready; i++)
{
if(!(event[i].events & EPOLLIN)) //只接收请求连接的可读事件
continue;
if(event[i].data.fd == httpfd)
do_accept(httpfd,epofd);
else
do_read(event[i].data.fd,epofd); //读取浏览器（客户端）发送的http协议消息
}
}
}
int main()
{
int port = 8888;
int httpfd = create_listenfd(port);
epoll_run(httpfd);
close(httpfd);
return 0;
}