基于http的多进程并发文件服务器

1 可以掌握的知识点

(1) 线上部署时的守护应用

(2) 常规的文件操作，配置文件读取

(3) 网络编程，端口复用等文件

(4) 多进程知识

2 代码注释如下

test_httpd.h

 #include <pwd.h>
 #include <grp.h>
 #include <net/if.h>
 #include <sys/ioctl.h>
 #include <sys/syslog.h>
 #include <stdarg.h>
 #include <errno.h>
 #include <stdio.h>
 #include <fcntl.h>
 #include <unistd.h>
 #include <string.h>
 #include <time.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <dirent.h>
 #include <errno.h>
 #include <netinet/in.h>
 #include <sys/socket.h>
 #include <resolv.h>
 #include <arpa/inet.h>
 #include <stdlib.h>
 #include <signal.h>
 #include <getopt.h>
 #include <net/if.h>
 #include <sys/ioctl.h>

 #define MAXBUF        1024
 #define MAXPATH        128

 char buffer[MAXBUF + ];
 char ip[];//存储字符串形式的Ip地址
 char port[];//存储字符串形式的端口
 char back[];//listen队列大小
 char home_dir[];//浏览主目录

 void wrtinfomsg(char *msg)
 {
     syslog(LOG_INFO,"%s",msg);
 }

 //读取配置文件
 int get_arg (char *cmd)
 {

         FILE* fp;
         char buffer[];
         size_t bytes_read;
         char* match;
         fp = fopen ("/etc/test_httpd.conf", "r");
         bytes_read = fread (buffer, , sizeof (buffer), fp);
         fclose (fp);

         if (bytes_read ==  || bytes_read == sizeof (buffer))
                 return ;
         buffer[bytes_read] = '\0';

         //根据配置文件key得到value
         if(!strncmp(cmd,"home_dir",))
         {
                 match = strstr (buffer, "home_dir=");
                 if (match == NULL)
                         return ;
                 bytes_read=sscanf(match,"home_dir=%s",home_dir);
                 return bytes_read;
         }

         else if(!strncmp(cmd,"port",))
         {
                 match = strstr (buffer, "port=");
                 if (match == NULL)
                         return ;
                 bytes_read=sscanf(match,"port=%s",port);
                 return bytes_read;
         }

         else if(!strncmp(cmd,"ip",))
         {
                 match = strstr (buffer, "ip=");
                 if (match == NULL)
                         return ;
                 bytes_read=sscanf(match,"ip=%s",ip);
                 return bytes_read;
         }
         else if(!strncmp(cmd,"back",))
         {
                 match = strstr (buffer, "back=");
                 if (match == NULL)
                         return ;
                 bytes_read=sscanf(match,"back=%s",back);
                 return bytes_read;
         }
      else
             return ;
 }

 //文件类型的判断
 char file_type(mode_t st_mode)
 {
     if ((st_mode & S_IFMT) == S_IFSOCK)
         return 's';
     else if ((st_mode & S_IFMT) == S_IFLNK)
         return 'l';
     else if ((st_mode & S_IFMT) == S_IFREG)
         return '-';
     else if ((st_mode & S_IFMT) == S_IFBLK)
         return 'b';
     else if ((st_mode & S_IFMT) == S_IFCHR)
         return 'c';
     else if ((st_mode & S_IFMT) == S_IFIFO)
         return 'p';
     else
         return 'd';
 }

 //search the up-path of dirpath
 char *dir_up(char *dirpath)
 {
     static char Path[MAXPATH];
     int len;

     strcpy(Path, dirpath);
     len = strlen(Path);
     if (len >  && Path[len - ] == '/')
         len--;
     while (Path[len - ] != '/' && len > )
         len--;
     Path[len] = ;
     return Path;
 }

 //如果路径是文件 就将文件的内容发送过去 如果是目录则列出目录文件
 void GiveResponse(FILE * client_sock, char *Path)
 {
     struct dirent *dirent;
     struct stat info;
     char Filename[MAXPATH];
     DIR *dir;
     int fd, len, ret;
     char *p, *realPath, *realFilename, *nport;

     struct passwd *p_passwd;
     struct group *p_group;
     char *p_time;    

     //get th dir or file
     len = strlen(home_dir) + strlen(Path) + ;
     realPath = malloc(len + );
     bzero(realPath, len + );
     sprintf(realPath, "%s/%s", home_dir, Path);//获取文件的绝对路径

     //get port
     len = strlen(port) + ;
     nport = malloc(len + );
     bzero(nport, len + );
     sprintf(nport, ":%s", port);//存储端口信息

     //获取文件属性
     if (stat(realPath, &info)) {
         //获取失败   输出这样信息 这信息格式满足http协议
         fprintf(client_sock,
                 "HTTP/1.1 200 OK\r\nServer:Test http server\r\nConnection: close\r\n\r\n<html><head><title>%d - %s</title></head>"
                 "<body><font size=+4>Linux HTTP server</font><br><hr width=\"100%%\"><br><center>"
                 "<table border cols=3 width=\"100%%\">", errno,
                 strerror(errno));
         fprintf(client_sock,
                 "</table><font color=\"CC0000\" size=+2> connect to administrator, error code is: \n%s %s</font></body></html>",
                 Path, strerror(errno));
         goto out;
     }

     //如果是文件则下载
     if (S_ISREG(info.st_mode))
     {
         fd = open(realPath, O_RDONLY);
         len = lseek(fd, , SEEK_END);
         p = (char *) malloc(len + );
         bzero(p, len + );
         lseek(fd, , SEEK_SET);
         //这里是一次性读取 小文件
         ret = read(fd, p, len);
         close(fd);
         fprintf(client_sock,
                 "HTTP/1.1 200 OK\r\nServer: Test http server\r\nConnection: keep-alive\r\nContent-type: application/*\r\nContent-Length:%d\r\n\r\n", len);

         fwrite(p, len, , client_sock);
         free(p);
     }
     else if (S_ISDIR(info.st_mode))
     {

     //列出目录
         dir = opendir(realPath);
         fprintf(client_sock,
                 "HTTP/1.1 200 OK\r\nServer:Test http server\r\nConnection:close\r\n\r\n<html><head><title>%s</title></head>"
                 "<body><font size=+4>Linux HTTP server file</font><br><hr width=\"100%%\"><br><center>"
                 "<table border cols=3 width=\"100%%\">", Path);
         fprintf(client_sock,
                 "<caption><font size=+3> Directory %s</font></caption>\n",
                 Path);
         fprintf(client_sock,
                 "<tr><td>name</td><td>type</td><td>owner</td><td>group</td><td>size</td><td>modify time</td></tr>\n");
         if (dir == NULL) {
             fprintf(client_sock, "</table><font color=\"CC0000\" size=+2>%s</font></body></html>",
                     strerror(errno));
             return;
         }
         while ((dirent = readdir(dir)) != NULL)
         {
             if (strcmp(Path, "/") == )
                 sprintf(Filename, "/%s", dirent->d_name);
             else
                 sprintf(Filename, "%s/%s", Path, dirent->d_name);
             if(dirent->d_name[]=='.')
                 continue;
             fprintf(client_sock, "<tr>");
             len = strlen(home_dir) + strlen(Filename) + ;
             realFilename = malloc(len + );
             bzero(realFilename, len + );
             sprintf(realFilename, "%s/%s", home_dir, Filename);
             if (stat(realFilename, &info) == )
             {
                 if (strcmp(dirent->d_name, "..") == )
                     fprintf(client_sock, "<td><a href=\"http://%s%s%s\">(parent)</a></td>",
                             ip, atoi(port) ==  ? "" : nport,dir_up(Path));
                 else
                     fprintf(client_sock, "<td><a href=\"http://%s%s%s\">%s</a></td>",
                             ip, atoi(port) ==  ? "" : nport, Filename, dirent->d_name);

                   p_time = ctime(&info.st_mtime);//获取文件修改时间
                    p_passwd = getpwuid(info.st_uid);    //获取文件拥有着
                    p_group = getgrgid(info.st_gid);//获取文件拥有者组

                   fprintf(client_sock, "<td>%c</td>", file_type(info.st_mode));
                    fprintf(client_sock, "<td>%s</td>", p_passwd->pw_name);
                   fprintf(client_sock, "<td>%s</td>", p_group->gr_name);
                   fprintf(client_sock, "<td>%d</td>", info.st_size);
                 fprintf(client_sock, "<td>%s</td>", ctime(&info.st_ctime));
             }
             fprintf(client_sock, "</tr>\n");
             free(realFilename);
         }
         fprintf(client_sock, "</table></center></body></html>");
     } else {
       //if others,forbid access
         fprintf(client_sock,
                 "HTTP/1.1 200 OK\r\nServer:Test http server\r\nConnection: close\r\n\r\n<html><head><title>permission denied</title></head>"
                 "<body><font size=+4>Linux HTTP server</font><br><hr width=\"100%%\"><br><center>"
                 "<table border cols=3 width=\"100%%\">");
         fprintf(client_sock,
                 "</table><font color=\"CC0000\" size=+2> you access resource '%s' forbid to access,communicate with the admintor </font></body></html>",
                 Path);
     }
   out:
     free(realPath);
     free(nport);
 }

 //守护
 void init_daemon(const char *pname, int facility)
 {
     int pid;
     int i;
     signal(SIGTTOU,SIG_IGN);
     signal(SIGTTIN,SIG_IGN);
     signal(SIGTSTP,SIG_IGN);
     signal(SIGHUP ,SIG_IGN);
     if(pid=fork())
         exit(EXIT_SUCCESS);
     else if(pid< )
     {
         perror("fork");
         exit(EXIT_FAILURE);
     }
     setsid();
     if(pid=fork())
         exit(EXIT_SUCCESS);
     else if(pid< )
     {
         perror("fork");
         exit(EXIT_FAILURE);
     }
     for(i=;i< NOFILE;++i)
         close(i);
     chdir("/tmp");
     umask();
     signal(SIGCHLD,SIG_IGN);
     openlog(pname, LOG_PID, facility);
     return;
 } 

 //如果配置文件不指定ip  那么默认读取eth0
 int get_addr(char *str)
 {
         int inet_sock;
         struct ifreq ifr;
         inet_sock = socket(AF_INET, SOCK_DGRAM, );
         strcpy(ifr.ifr_name, str);
         if (ioctl(inet_sock, SIOCGIFADDR, &ifr) < )
         {
             wrtinfomsg("bind");
             exit(EXIT_FAILURE);
         }
         sprintf(ip,"%s", inet_ntoa(((struct sockaddr_in*)&(ifr.ifr_addr))->sin_addr));
 }

test_httpd.c

 #include"test_httpd.h"

 int main(int argc, char **argv)
 {
     struct sockaddr_in addr;
     int sock_fd, addrlen;

     init_daemon(argv[],LOG_INFO);
     if(get_arg("home_dir")==)
     {
         sprintf(home_dir,"%s","/tmp");
     }
     if(get_arg("ip")==)
     {
         get_addr("eth0");
     }
     if(get_arg("port")==)
     {
         sprintf(port,"%s","");
     }
     if(get_arg("back")==)
     {
         sprintf(back,"%s","");
     }

     if ((sock_fd = socket(PF_INET, SOCK_STREAM, )) < )
     {
         wrtinfomsg("socket()");
         exit(EXIT_FAILURE);
     }
     addrlen = ;
     //端口复用 选项SO_REUSEADDR
     setsockopt(sock_fd, SOL_SOCKET, SO_REUSEADDR, &addrlen, sizeof(addrlen));

     addr.sin_family = AF_INET;
     addr.sin_port = htons(atoi(port));
     addr.sin_addr.s_addr = inet_addr(ip);
     addrlen = sizeof(struct sockaddr_in);
     if (bind(sock_fd, (struct sockaddr *) &addr, addrlen) < )
     {
         wrtinfomsg("bind");
         exit(EXIT_FAILURE);
     }
     if (listen(sock_fd, atoi(back)) < )
     {
         wrtinfomsg("listen");
         exit(EXIT_FAILURE);
     }
     while ()
     {
         int len;
         int new_fd;
         addrlen = sizeof(struct sockaddr_in);

         new_fd = accept(sock_fd, (struct sockaddr *) &addr, &addrlen);
         if (new_fd < )
         {
             wrtinfomsg("accept");
             exit(EXIT_FAILURE);
         }

         bzero(buffer, MAXBUF + );
         sprintf(buffer, "connect come from: %s:%d\n",
                 inet_ntoa(addr.sin_addr), ntohs(addr.sin_port));
         wrtinfomsg(buffer);

           //fork a new process to deal with the connect ,the parent continue wait for new connect
        pid_t pid;
        if((pid=fork())==-)
        {
             wrtinfomsg("fork");
             exit(EXIT_FAILURE);
         }
        if (pid==)
        {
             close(sock_fd);
             bzero(buffer, MAXBUF + );
             if ((len = recv(new_fd, buffer, MAXBUF, )) > )
             {
                 FILE *ClientFP = fdopen(new_fd, "w");
                 if (ClientFP == NULL)
                 {
                     wrtinfomsg("fdopen");
                     exit(EXIT_FAILURE);
                 }
                 else
                 {
                     char Req[MAXPATH + ] = "";
                     sscanf(buffer, "GET %s HTTP", Req);
                     bzero(buffer, MAXBUF + );
                     sprintf(buffer, "Reuquest get the file: \"%s\"\n", Req);
                     wrtinfomsg(buffer);
                     GiveResponse(ClientFP, Req);
                     fclose(ClientFP);
                 }
             }
             exit(EXIT_SUCCESS);
         }
         else
         {
             close(new_fd);
             continue;
         }
     }
     close(sock_fd);
     return ;
 } 

makefile

test_httpd: test_httpd.c test_httpd.h
    gcc -o test_httpd test_httpd.c test_httpd.h

install:
    cp test_httpd.conf /etc/test_httpd.conf
    cp test_httpd /usr/bin/test_httpd

clean:
    rm test_httpd

uninstall:
    rm /usr/bin/test_httpd

test_httpd.conf

 home_dir=/var
 port=
 back=
 ip=写上自己主机上面的IP或者不写

3 运行方法

(1)make

(2)make install 这个时候会把程序添加在PATH路径下

(3)查看端口是否打开

(4)./test_httpd

(5)浏览器访问 htpp://你的ip:port(默认位80，如果指定就写上自己制定的端口)

后面学习线程池的文件服务器