Linux网络编程:一个HTTP协议的目录浏览和文件下载服务器

服务器源代码如下：

  1. #include <stdarg.h>
  2. #include <errno.h>
  3. #include <stdio.h>
  4. #include <fcntl.h>
  5. #include <unistd.h>
  6. #include <string.h>
  7. #include <time.h>
  8. #include <sys/types.h>
  9. #include <sys/stat.h>
  10. #include <dirent.h>
  11. #include <errno.h>
  12. #include <netinet/in.h>
  13. #include <sys/socket.h>
  14. #include <resolv.h>
  15. #include <arpa/inet.h>
  16. #include <stdlib.h>
  17. #include <signal.h>
  18. #include <getopt.h>
  20. #define DEFAULTIP "127.0.0.1"
  21. #define DEFAULTPORT "80"
  22. #define DEFAULTBACK "10"
  23. #define DEFAULTDIR "/home"
  24. #define DEFAULTLOG "/tmp/das-server.log"
  26. void prterrmsg(char *msg);
  27. #define prterrmsg(msg)        { perror(msg); abort(); }
  28. void wrterrmsg(char *msg);
  29. #define wrterrmsg(msg)        { fputs(msg, logfp); fputs(strerror(errno), logfp);fflush(logfp); abort(); }
  31. void prtinfomsg(char *msg);
  32. #define prtinfomsg(msg)        { fputs(msg, stdout);  }
  33. void wrtinfomsg(char *msg);
  34. #define wrtinfomsg(msg)        {  fputs(msg, logfp); fflush(logfp);}
  36. #define MAXBUF        1024
  38. char buffer[MAXBUF + 1];
  39. char *host = 0;
  40. char *port = 0;
  41. char *back = 0;
  42. char *dirroot = 0;
  43. char *logdir = 0;
  44. unsigned char daemon_y_n = 0;
  45. FILE *logfp;
  47. #define MAXPATH        150
  49. /*----------------------------------------
  50. *--- dir_up - 查找dirpath所指目录的上一级目录
  51. *----------------------------------------
  52. */
  53. char *dir_up(char *dirpath)
  54. {
  55.     static char Path[MAXPATH];
  56.     int len;
  58.     strcpy(Path, dirpath);
  59.     len = strlen(Path);
  60.     if (len > 1 && Path[len - 1] == '/')
  61.         len--;
  62.     while (Path[len - 1] != '/' && len > 1)
  63.         len--;
  64.     Path[len] = 0;
  65.     return Path;
  66. }
  68. /*------------------------------------------------------
  69. *--- AllocateMemory - 分配空间并把d所指的内容复制
  70. *------------------------------------------------------
  71. */
  72. void AllocateMemory(char **s, int l, char *d)
  73. {
  74.     *s = malloc(l + 1);
  75.     bzero(*s, l + 1);
  76.     memcpy(*s, d, l);
  77. }
  78. /************关于本文档********************************************
  79. *filename: das-server.c
  80. *purpose: 这是在Linux下用C语言写的目录访问服务器，支持目录浏览和文件下载
  81. *wrote by: zhoulifa(zhoulifa@163.com) 周立发(http://zhoulifa.bokee.com)
  82. Linux爱好者 Linux知识传播者 SOHO族 开发者 最擅长C语言
  83. *date time:2007-01-26 19:32
  84. *Note: 任何人可以任意复制代码并运用这些文档，当然包括你的商业用途
  85. * 但请遵循GPL
  86. *Thanks to: Google.com
  87. *Hope:希望越来越多的人贡献自己的力量，为科学技术发展出力
  88. * 科技站在巨人的肩膀上进步更快！感谢有开源前辈的贡献！
  89. *********************************************************************/
  90. /*------------------------------------------------------
  91. *--- GiveResponse - 把Path所指的内容发送到client_sock去
  92. *-------------------如果Path是一个目录，则列出目录内容
  93. *-------------------如果Path是一个文件，则下载文件
  94. *------------------------------------------------------
  95. */
  96. void GiveResponse(FILE * client_sock, char *Path)
  97. {
  98.     struct dirent *dirent;
  99.     struct stat info;
  100.     char Filename[MAXPATH];
  101.     DIR *dir;
  102.     int fd, len, ret;
  103.     char *p, *realPath, *realFilename, *nport;
  105.     /* 获得实际工作目录或文件 */
  106.     len = strlen(dirroot) + strlen(Path) + 1;
  107.     realPath = malloc(len + 1);
  108.     bzero(realPath, len + 1);
  109.     sprintf(realPath, "%s/%s", dirroot, Path);
  111.     /* 获得实际工作端口 */
  112.     len = strlen(port) + 1;
  113.     nport = malloc(len + 1);
  114.     bzero(nport, len + 1);
  115.     sprintf(nport, ":%s", port);
  117.     /* 获得实际工作目录或文件的信息以判断是文件还是目录 */
  118.     if (stat(realPath, &info)) {
  119.         fprintf(client_sock,
  120.                 "HTTP/1.1 200 OK\r\nServer: DAS by ZhouLifa\r\nConnection: close\r\n\r\n<html><head><title>%d - %s</title></head>"
  121.                 "<body><font size=+4>Linux 下目录访问服务器</font><br><hr width=\"100%%\"><br><center>"
  122.                 "<table border cols=3 width=\"100%%\">", errno,
  123.                 strerror(errno));
  124.         fprintf(client_sock,
  125.                 "</table><font color=\"CC0000\" size=+2>请向管理员咨询为何出现如下错误提示：\n%s %s</font></body></html>",
  126.                 Path, strerror(errno));
  127.         goto out;
  128.     }
  129.     /* 处理浏览文件请求，即下载文件 */
  130.     if (S_ISREG(info.st_mode)) {
  131.         fd = open(realPath, O_RDONLY);
  132.         len = lseek(fd, 0, SEEK_END);
  133.         p = (char *) malloc(len + 1);
  134.         bzero(p, len + 1);
  135.         lseek(fd, 0, SEEK_SET);
  136.         ret = read(fd, p, len);
  137.         close(fd);
  138.         fprintf(client_sock,
  139.                 "HTTP/1.1 200 OK\r\nServer: DAS by ZhouLifa\r\nConnection: keep-alive\r\nContent-type: application/*\r\nContent-Length:%d\r\n\r\n",
  140.                 len);
  141.         fwrite(p, len, 1, client_sock);
  142.         free(p);
  143.     } else if (S_ISDIR(info.st_mode)) {
  144.         /* 处理浏览目录请求 */
  145.         dir = opendir(realPath);
  146.         fprintf(client_sock,
  147.                 "HTTP/1.1 200 OK\r\nServer: DAS by ZhouLifa\r\nConnection: close\r\n\r\n<html><head><title>%s</title></head>"
  148.                 "<body><font size=+4>Linux 下目录访问服务器</font><br><hr width=\"100%%\"><br><center>"
  149.                 "<table border cols=3 width=\"100%%\">", Path);
  150.         fprintf(client_sock,
  151.                 "<caption><font size=+3>目录 %s</font></caption>\n",
  152.                 Path);
  153.         fprintf(client_sock,
  154.                 "<tr><td>名称</td><td>大小</td><td>修改时间</td></tr>\n");
  155.         if (dir == 0) {
  156.             fprintf(client_sock,
  157.                     "</table><font color=\"CC0000\" size=+2>%s</font></body></html>",
  158.                     strerror(errno));
  159.             return;
  160.         }
  161.         /* 读取目录里的所有内容 */
  162.         while ((dirent = readdir(dir)) != 0) {
  163.             if (strcmp(Path, "/") == 0)
  164.                 sprintf(Filename, "/%s", dirent->d_name);
  165.             else
  166.                 sprintf(Filename, "%s/%s", Path, dirent->d_name);
  167.             fprintf(client_sock, "<tr>");
  168.             len = strlen(dirroot) + strlen(Filename) + 1;
  169.             realFilename = malloc(len + 1);
  170.             bzero(realFilename, len + 1);
  171.             sprintf(realFilename, "%s/%s", dirroot, Filename);
  172.             if (stat(realFilename, &info) == 0) {
  173.                 if (strcmp(dirent->d_name, "..") == 0)
  174.                     fprintf(client_sock,
  175.                             "<td><a href=\"http://%s%s%s\">(parent)</a></td>",
  176.                             host, atoi(port) == 80 ? "" : nport,
  177.                             dir_up(Path));
  178.                 else
  179.                     fprintf(client_sock,
  180.                             "<td><a href=\"http://%s%s%s\">%s</a></td>",
  181.                             host, atoi(port) == 80 ? "" : nport, Filename,
  182.                             dirent->d_name);
  183.                 if (S_ISDIR(info.st_mode))
  184.                     fprintf(client_sock, "<td>目录</td>");
  185.                 else if (S_ISREG(info.st_mode))
  186.                     fprintf(client_sock, "<td>%d</td>", info.st_size);
  187.                 else if (S_ISLNK(info.st_mode))
  188.                     fprintf(client_sock, "<td>链接</td>");
  189.                 else if (S_ISCHR(info.st_mode))
  190.                     fprintf(client_sock, "<td>字符设备</td>");
  191.                 else if (S_ISBLK(info.st_mode))
  192.                     fprintf(client_sock, "<td>块设备</td>");
  193.                 else if (S_ISFIFO(info.st_mode))
  194.                     fprintf(client_sock, "<td>FIFO</td>");
  195.                 else if (S_ISSOCK(info.st_mode))
  196.                     fprintf(client_sock, "<td>Socket</td>");
  197.                 else
  198.                     fprintf(client_sock, "<td>(未知)</td>");
  199.                 fprintf(client_sock, "<td>%s</td>", ctime(&info.st_ctime));
  200.             }
  201.             fprintf(client_sock, "</tr>\n");
  202.             free(realFilename);
  203.         }
  204.         fprintf(client_sock, "</table></center></body></html>");
  205.     } else {
  206.         /* 既非常规文件又非目录，禁止访问 */
  207.         fprintf(client_sock,
  208.                 "HTTP/1.1 200 OK\r\nServer: DAS by ZhouLifa\r\nConnection: close\r\n\r\n<html><head><title>permission denied</title></head>"
  209.                 "<body><font size=+4>Linux 下目录访问服务器</font><br><hr width=\"100%%\"><br><center>"
  210.                 "<table border cols=3 width=\"100%%\">");
  211.         fprintf(client_sock,
  212.                 "</table><font color=\"CC0000\" size=+2>你访问的资源'%s'被禁止访问，请联系管理员解决！</font></body></html>",
  213.                 Path);
  214.     }
  215.   out:
  216.     free(realPath);
  217.     free(nport);
  218. }
  220. /*------------------------------------------------------
  221. *--- getoption - 分析取出程序的参数
  222. *------------------------------------------------------
  223. */
  224. void getoption(int argc, char **argv)
  225. {
  226.     int c, len;
  227.     char *p = 0;
  229.     opterr = 0;
  230.     while (1) {
  231.         int option_index = 0;
  232.         static struct option long_options[] = {
  233.             {"host", 1, 0, 0},
  234.             {"port", 1, 0, 0},
  235.             {"back", 1, 0, 0},
  236.             {"dir", 1, 0, 0},
  237.             {"log", 1, 0, 0},
  238.             {"daemon", 0, 0, 0},
  239.             {0, 0, 0, 0}
  240.         };
  241.         /* 本程序支持如一些参数：
  242.          * --host IP地址 或者 -H IP地址
  243.          * --port 端口 或者 -P 端口
  244.          * --back 监听数量 或者 -B 监听数量
  245.          * --dir 网站根目录 或者 -D 网站根目录
  246.          * --log 日志存放路径 或者 -L 日志存放路径
  247.          * --daemon 使程序进入后台运行模式
  248.          */
  249.         c = getopt_long(argc, argv, "H:P:B:D:L",
  250.                         long_options, &option_index);
  251.         if (c == -1 || c == '?')
  252.             break;
  254.         if(optarg)        len = strlen(optarg);
  255.         else        len = 0;
  257.         if ((!c && !(strcasecmp(long_options[option_index].name, "host")))
  258.             || c == 'H')
  259.             p = host = malloc(len + 1);
  260.         else if ((!c
  261.                   &&
  262.                   !(strcasecmp(long_options[option_index].name, "port")))
  263.                  || c == 'P')
  264.             p = port = malloc(len + 1);
  265.         else if ((!c
  266.                   &&
  267.                   !(strcasecmp(long_options[option_index].name, "back")))
  268.                  || c == 'B')
  269.             p = back = malloc(len + 1);
  270.         else if ((!c
  271.                   && !(strcasecmp(long_options[option_index].name, "dir")))
  272.                  || c == 'D')
  273.             p = dirroot = malloc(len + 1);
  274.         else if ((!c
  275.                   && !(strcasecmp(long_options[option_index].name, "log")))
  276.                  || c == 'L')
  277.             p = logdir = malloc(len + 1);
  278.         else if ((!c
  279.                   &&
  280.                   !(strcasecmp
  281.                     (long_options[option_index].name, "daemon")))) {
  282.             daemon_y_n = 1;
  283.             continue;
  284.         }
  285.         else
  286.             break;
  287.         bzero(p, len + 1);
  288.         memcpy(p, optarg, len);
  289.     }
  290. }
  292. int main(int argc, char **argv)
  293. {
  294.     struct sockaddr_in addr;
  295.     int sock_fd, addrlen;
  297.     /* 获得程序工作的参数，如 IP 、端口、监听数、网页根目录、目录存放位置等 */
  298.     getoption(argc, argv);
  300.     if (!host) {
  301.         addrlen = strlen(DEFAULTIP);
  302.         AllocateMemory(&host, addrlen, DEFAULTIP);
  303.     }
  304.     if (!port) {
  305.         addrlen = strlen(DEFAULTPORT);
  306.         AllocateMemory(&port, addrlen, DEFAULTPORT);
  307.     }
  308.     if (!back) {
  309.         addrlen = strlen(DEFAULTBACK);
  310.         AllocateMemory(&back, addrlen, DEFAULTBACK);
  311.     }
  312.     if (!dirroot) {
  313.         addrlen = strlen(DEFAULTDIR);
  314.         AllocateMemory(&dirroot, addrlen, DEFAULTDIR);
  315.     }
  316.     if (!logdir) {
  317.         addrlen = strlen(DEFAULTLOG);
  318.         AllocateMemory(&logdir, addrlen, DEFAULTLOG);
  319.     }
  321.     printf
  322.         ("host=%s port=%s back=%s dirroot=%s logdir=%s %s是后台工作模式(进程ID：%d)\n",
  323.          host, port, back, dirroot, logdir, daemon_y_n?"":"不", getpid());
  325.     /* fork() 两次处于后台工作模式下 */
  326.     if (daemon_y_n) {
  327.         if (fork())
  328.             exit(0);
  329.         if (fork())
  330.             exit(0);
  331.         close(0), close(1), close(2);
  332.         logfp = fopen(logdir, "a+");
  333.         if (!logfp)
  334.             exit(0);
  335.     }
  337.     /* 处理子进程退出以免产生僵尸进程 */
  338.     signal(SIGCHLD, SIG_IGN);
  340.     /* 创建 socket */
  341.     if ((sock_fd = socket(PF_INET, SOCK_STREAM, 0)) < 0) {
  342.         if (!daemon_y_n) {
  343.             prterrmsg("socket()");
  344.         } else {
  345.             wrterrmsg("socket()");
  346.         }
  347.     }
  349.     /* 设置端口快速重用 */
  350.     addrlen = 1;
  351.     setsockopt(sock_fd, SOL_SOCKET, SO_REUSEADDR, &addrlen,
  352.                sizeof(addrlen));
  354.     addr.sin_family = AF_INET;
  355.     addr.sin_port = htons(atoi(port));
  356.     addr.sin_addr.s_addr = inet_addr(host);
  357.     addrlen = sizeof(struct sockaddr_in);
  358.     /* 绑定地址、端口等信息 */
  359.     if (bind(sock_fd, (struct sockaddr *) &addr, addrlen) < 0) {
  360.         if (!daemon_y_n) {
  361.             prterrmsg("bind()");
  362.         } else {
  363.             wrterrmsg("bind()");
  364.         }
  365.     }
  367.     /* 开启临听 */
  368.     if (listen(sock_fd, atoi(back)) < 0) {
  369.         if (!daemon_y_n) {
  370.             prterrmsg("listen()");
  371.         } else {
  372.             wrterrmsg("listen()");
  373.         }
  374.     }
  375.     while (1) {
  376.         int len;
  377.         int new_fd;
  378.         addrlen = sizeof(struct sockaddr_in);
  379.         /* 接受新连接请求 */
  380.         new_fd = accept(sock_fd, (struct sockaddr *) &addr, &addrlen);
  381.         if (new_fd < 0) {
  382.             if (!daemon_y_n) {
  383.                 prterrmsg("accept()");
  384.             } else {
  385.                 wrterrmsg("accept()");
  386.             }
  387.             break;
  388.         }
  389.         bzero(buffer, MAXBUF + 1);
  390.         sprintf(buffer, "连接来自于: %s:%d\n",
  391.                 inet_ntoa(addr.sin_addr), ntohs(addr.sin_port));
  392.         if (!daemon_y_n) {
  393.             prtinfomsg(buffer);
  394.         } else {
  395.             wrtinfomsg(buffer);
  396.         }
  397.         /* 产生一个子进程去处理请求，当前进程继续等待新的连接到来 */
  398.         if (!fork()) {
  399.             bzero(buffer, MAXBUF + 1);
  400.             if ((len = recv(new_fd, buffer, MAXBUF, 0)) > 0) {
  401.                 FILE *ClientFP = fdopen(new_fd, "w");
  402.                 if (ClientFP == NULL) {
  403.                     if (!daemon_y_n) {
  404.                         prterrmsg("fdopen()");
  405.                     } else {
  406.                         prterrmsg("fdopen()");
  407.                     }
  408.                 } else {
  409.                     char Req[MAXPATH + 1] = "";
  410.                     sscanf(buffer, "GET %s HTTP", Req);
  411.                     bzero(buffer, MAXBUF + 1);
  412.                     sprintf(buffer, "请求取文件: \"%s\"\n", Req);
  413.                     if (!daemon_y_n) {
  414.                         prtinfomsg(buffer);
  415.                     } else {
  416.                         wrtinfomsg(buffer);
  417.                     }
  418.                     /* 处理用户请求 */
  419.                     GiveResponse(ClientFP, Req);
  420.                     fclose(ClientFP);
  421.                 }
  422.             }
  423.             exit(0);
  424.         }
  425.         close(new_fd);
  426.     }
  427.     close(sock_fd);
  428.     return 0;
  429. }

复制代码

编译程序用下列命令：
gcc -Wall das-server.c -o das-server
注：das即 Dictory Access Server
以root用户启动服务程序用下列命令：
./das-server
或以普通用户启动服务程序用下列命令：
./das-server --port 7838
或
./das-server -P 7838
注：只有root用户才有权限启动1024以下的端口，所以如果想用默认的80端口就得用root来运行。
如果要想让程序在后台自动运行，即处理精灵模式下工作，在命令后面加上--daemon参数即可。
打开一个网络浏览器输入服务地址开始浏览，如下图：

下载文件如下图：

注：请不要下载较大的文件，比如文件大小超过10M的，因为程序是一次分配内存，会占用系统内存较大导致系统死掉！

posted @ 2013-07-16 17:36  mickole  阅读(759)  评论(0)  编辑  收藏  举报