嵌入式Web服务器BOA移植

BOA工作流程：

1.修正BOA服务器的更目录。

static void fixup_server_root()
{
    if (!server_root) {
#ifdef SERVER_ROOT
        server_root = strdup(SERVER_ROOT);
        if (!server_root) {
            perror("strdup (SERVER_ROOT)");
            exit(EXIT_FAILURE);
        }
#else
        fputs("boa: don't know where server root is.  Please #define "
              "SERVER_ROOT in boa.h\n"
              "and recompile, or use the -c command line option to "
              "specify it.\n", stderr);
        exit(EXIT_FAILURE);
#endif
    }

    if (chdir(server_root) == -1) {
        fprintf(stderr, "Could not chdir to \"%s\": aborting\n",
                server_root);
        exit(EXIT_FAILURE);
    }
}

2.读boa .conf配置文件。

/*
 * Name: read_config_files
 *
 * Description: Reads config files, then makes sure that
 * all required variables were set properly.
 */
void read_config_files(void)
{
    FILE *config;

    current_uid = getuid();

    if (!config_file_name) {
        config_file_name = DEFAULT_CONFIG_FILE;
    }
#ifdef ACCESS_CONTROL
    access_init();
#endif                          /* ACCESS_CONTROL */

    config = fopen(config_file_name, "r");  //已只读方式打开配置文件boa.conf
    if (!config) {
        fputs("Could not open boa.conf for reading.\n", stderr);  //打印打开文件失败的信息
        exit(EXIT_FAILURE);
    }
    parse(config);
    fclose(config);

    if (!server_name) {            //如果没有指定服务器名字则指定服务器名字
        struct hostent *he;
        char temp_name[100];

        if (gethostname(temp_name, 100) == -1) {  //获取服务器名字
            perror("gethostname:");
            exit(EXIT_FAILURE);
        }

        he = gethostbyname(temp_name);     //获取主机
        if (he == NULL) {
            perror("gethostbyname:");
            exit(EXIT_FAILURE);
        }

        server_name = strdup(he->h_name);      //获取主机名
        if (server_name == NULL) {
            perror("strdup:");
            exit(EXIT_FAILURE);
        }
    }
    tempdir = getenv("TMP");
    if (tempdir == NULL)
        tempdir = "/tmp";

    if (single_post_limit < 0) {
        fprintf(stderr, "Invalid value for single_post_limit: %d\n",
                single_post_limit);
        exit(EXIT_FAILURE);
    }

    if (vhost_root && virtualhost) {
        fprintf(stderr, "Both VHostRoot and VirtualHost were enabled, and "
                "they are mutually exclusive.\n");
        exit(EXIT_FAILURE);
    }

    if (vhost_root && document_root) {
        fprintf(stderr,
                "Both VHostRoot and DocumentRoot were enabled, and "
                "they are mutually exclusive.\n");
        exit(EXIT_FAILURE);
    }

    if (!default_vhost) {
        default_vhost = DEFAULT_VHOST;
    }

#ifdef USE_SETRLIMIT
    if (cgi_rlimit_cpu < 0)
        cgi_rlimit_cpu = 0;

    if (cgi_rlimit_data < 0)
        cgi_rlimit_data = 0;

    if (cgi_nice < 0)
        cgi_nice = 0;
#endif

    if (max_connections < 1) {
        struct rlimit rl;
        int c;

        /* has not been set explicitly */
        c = getrlimit(RLIMIT_NOFILE, &rl);
        if (c < 0) {
            DIE("getrlimit");
        }
        max_connections = rl.rlim_cur;
    }
    if (max_connections > FD_SETSIZE - 20)
        max_connections = FD_SETSIZE - 20;

    if (ka_timeout < 0) ka_timeout=0;  /* not worth a message */
    /* save some time */
    default_timeout = (ka_timeout ? ka_timeout : REQUEST_TIMEOUT);
#ifdef HAVE_POLL
    default_timeout *= 1000;
#endif

    if (default_type == NULL) {
        DIE("DefaultType *must* be set!");
    }
}

3.写日志文件。

/*
 * Name: open_logs
 *
 * Description: Opens access log, error log, and if specified, CGI log
 * Ties stderr to error log, except during CGI execution, at which
 * time CGI log is the stderr for CGIs.
 *
 * Access log is line buffered, error log is not buffered.
 *
 */

void open_logs(void)
{
    int access_log;

    /* if error_log_name is set, dup2 stderr to it */
    /* otherwise, leave stderr alone */
    /* we don't want to tie stderr to /dev/null */
    if (error_log_name) {
        int error_log;

        /* open the log file */
        error_log = open_gen_fd(error_log_name);
        if (error_log < 0) {
            DIE("unable to open error log");
        }

        /* redirect stderr to error_log */
        if (dup2(error_log, STDERR_FILENO) == -1) {
            DIE("unable to dup2 the error log");
        }
        close(error_log);
    }

    if (access_log_name) {
        access_log = open_gen_fd(access_log_name);
    } else {
        access_log = open("/dev/null", 0);
    }
    if (access_log < 0) {
        DIE("unable to open access log");
    }

    if (dup2(access_log, STDOUT_FILENO) == -1) {
        DIE("can't dup2 /dev/null to STDOUT_FILENO");
    }
    if (fcntl(access_log, F_SETFD, 1) == -1) {
        DIE("unable to set close-on-exec flag for access_log");
    }

    close(access_log);

    if (cgi_log_name) {
        cgi_log_fd = open_gen_fd(cgi_log_name);
        if (cgi_log_fd == -1) {
            WARN("open cgi_log");
            free(cgi_log_name);
            cgi_log_name = NULL;
            cgi_log_fd = 0;
        } else {
            if (fcntl(cgi_log_fd, F_SETFD, 1) == -1) {
                WARN("unable to set close-on-exec flag for cgi_log");
                free(cgi_log_name);
                cgi_log_name = NULL;
                close(cgi_log_fd);
                cgi_log_fd = 0;
            }
        }
    }
#ifdef SETVBUF_REVERSED
    setvbuf(stderr, _IONBF, (char *) NULL, 0);
    setvbuf(stdout, _IOLBF, (char *) NULL, 0);
#else
    setvbuf(stderr, (char *) NULL, _IONBF, 0);
    setvbuf(stdout, (char *) NULL, _IOLBF, 0);
#endif
}

4.初始化Web服务器。

static int create_server_socket(void)
{
    int server_s;

    server_s = socket(SERVER_PF, SOCK_STREAM, IPPROTO_TCP);
    if (server_s == -1) {
        DIE("unable to create socket");
    }

    /* server socket is nonblocking */
    if (set_nonblock_fd(server_s) == -1) {
        DIE("fcntl: unable to set server socket to nonblocking");
    }

    /* close server socket on exec so CGIs can't write to it */
    if (fcntl(server_s, F_SETFD, 1) == -1) {
        DIE("can't set close-on-exec on server socket!");
    }

    /* reuse socket addr */
    if ((setsockopt(server_s, SOL_SOCKET, SO_REUSEADDR, (void *) &sock_opt,
                    sizeof (sock_opt))) == -1) {
        DIE("setsockopt");
    }

    /* Internet family-specific code encapsulated in bind_server()  */
    if (bind_server(server_s, server_ip, server_port) == -1) {
        DIE("unable to bind");
    }

    /* listen: large number just in case your kernel is nicely tweaked */
    if (listen(server_s, backlog) == -1) {
        DIE("unable to listen");
    }
    return server_s;
}

5.当有客户端连接请求到达时，Web服务器（BOA）负责接收客户端请求，并保存相关请求信息。

6.当收到客户端的连接请求之后，Web服务器分析客户端请求，解析出请求的方法、URL目标、可选的查询信息及表单信息，同时根据客户端的请求做出相应的处理。

7.Web服务器处理完客户端的请求后，向客户端发送响应信息，最后关闭与客户机的TCP连接。

BOA配置信息：

# Boa v0.94 configuration file
# File format has not changed from 0.93
# File format has changed little from 0.92
# version changes are noted in the comments
#
# The Boa configuration file is parsed with a custom parser.  If it
# reports an error, the line number will be provided; it should be easy
# to spot.  The syntax of each of these rules is very simple, and they
# can occur in any order.  Where possible these directives mimic those
# of NCSA httpd 1.3; I saw no reason to introduce gratuitous
# differences.

# $Id: boa.conf,v 1.3.2.6 2003/02/02 05:02:22 jnelson Exp $

# The "ServerRoot" is not in this configuration file.  It can be
# compiled into the server (see defines.h) or specified on the command
# line with the -c option, for example:
#
# boa -c /usr/local/boa


# Port: The port Boa runs on.  The default port for http servers is 80.
# If it is less than 1024, the server must be started as root.

Port 80

# Listen: the Internet address to bind(2) to.  If you leave it out,
# it takes the behavior before 0.93.17.2, which is to bind to all
# addresses (INADDR_ANY).  You only get one "Listen" directive,
# if you want service on multiple IP addresses, you have three choices:
#    1. Run boa without a "Listen" directive
#       a. All addresses are treated the same; makes sense if the addresses
#          are localhost, ppp, and eth0.
#       b. Use the VirtualHost directive below to point requests to different
#          files.  Should be good for a very large number of addresses (web
#          hosting clients).
#    2. Run one copy of boa per IP address, each has its own configuration
#       with a "Listen" directive.  No big deal up to a few tens of addresses.
#       Nice separation between clients.
# The name you provide gets run through inet_aton(3), so you have to use dotted
# quad notation.  This configuration is too important to trust some DNS.

#Listen 192.68.0.5

#  User: The name or UID the server should run as.
# Group: The group name or GID the server should run as.

User nobody
Group nogroup

# ServerAdmin: The email address where server problems should be sent.
# Note: this is not currently used, except as an environment variable
# for CGIs.

#ServerAdmin root@localhost

# PidFile: where to put the pid of the process.
# Comment out to write no pid file.
# Note: Because Boa drops privileges at startup, and the
# pid file is written by the UID/GID before doing so, Boa
# does not attempt removal of the pid file.
# PidFile /var/run/boa.pid

# ErrorLog: The location of the error log file. If this does not start
# with /, it is considered relative to the server root.
# Set to /dev/null if you don't want errors logged.
# If unset, defaults to /dev/stderr
# Please NOTE: Sending the logs to a pipe ('|'), as shown below,
#  is somewhat experimental and might fail under heavy load.
# "Usual libc implementations of printf will stall the whole
#  process if the receiving end of a pipe stops reading."
#ErrorLog "|/usr/sbin/cronolog --symlink=/var/log/boa/error_log /var/log/boa/error-%Y%m%d.log"

ErrorLog /var/log/boa/error_log

# AccessLog: The location of the access log file. If this does not
# start with /, it is considered relative to the server root.
# Comment out or set to /dev/null (less effective) to disable.
# Useful to set to /dev/stdout for use with daemontools.
# Access logging.  
# Please NOTE: Sending the logs to a pipe ('|'), as shown below,
#  is somewhat experimental and might fail under heavy load.
# "Usual libc implementations of printf will stall the whole
#  process if the receiving end of a pipe stops reading."
#AccessLog  "|/usr/sbin/cronolog --symlink=/var/log/boa/access_log /var/log/boa/access-%Y%m%d.log"

AccessLog /var/log/boa/access_log

# CGILog /var/log/boa/cgi_log
# CGILog: The location of the CGI stderr log file. If this does not
# start with /, it is considered relative to the server root.
# The log file would contain any contents send to /dev/stderr
# by the CGI. If this is commented out, it defaults to whatever 
# ErrorLog points.  Set to /dev/null to disable CGI stderr logging.
# Please NOTE: Sending the logs to a pipe ('|'), as shown below,
#  is somewhat experimental and might fail under heavy load.
# "Usual libc implementations of printf will stall the whole
#  process if the receiving end of a pipe stops reading."
#CGILog  "|/usr/sbin/cronolog --symlink=/var/log/boa/cgi_log /var/log/boa/cgi-%Y%m%d.log"

# CGIumask 027 (no mask for user, read-only for group, and nothing for user)
# CGIumask 027
# The CGIumask is set immediately before execution of the CGI.

# UseLocaltime: Logical switch.  Uncomment to use localtime 
# instead of UTC time
#UseLocaltime

# VerboseCGILogs: this is just a logical switch.
#  It simply notes the start and stop times of cgis in the error log
# Comment out to disable.

#VerboseCGILogs

# ServerName: the name of this server that should be sent back to 
# clients if different than that returned by gethostname + gethostbyname 

#ServerName www.your.org.here

# VirtualHost: a logical switch.
# Comment out to disable.
# Given DocumentRoot /var/www, requests on interface 'A' or IP 'IP-A'
# become /var/www/IP-A.
# Example: http://localhost/ becomes /var/www/127.0.0.1
#
# Not used until version 0.93.17.2.  This "feature" also breaks commonlog
# output rules, it prepends the interface number to each access_log line.
# You are expected to fix that problem with a postprocessing script.

#VirtualHost 


# VHostRoot: the root location for all virtually hosted data
# Comment out to disable.
# Incompatible with 'Virtualhost' and 'DocumentRoot'!!
# Given VHostRoot /var/www, requests to host foo.bar.com,
# where foo.bar.com is ip a.b.c.d,
# become /var/www/a.b.c.d/foo.bar.com 
# Hostnames are "cleaned", and must conform to the rules
# specified in rfc1034, which are be summarized here:
# 
# Hostnames must start with a letter, end with a letter or digit, 
# and have as interior characters only letters, digits, and hyphen.
# Hostnames must not exceed 63 characters in length.

#VHostRoot /var/www

# DefaultVHost
# Define this in order to have a default hostname when the client does not
# specify one, if using VirtualHostName. If not specified, the word
# "default" will be used for compatibility with older clients.

#DefaultVHost foo.bar.com

# DocumentRoot: The root directory of the HTML documents.
# Comment out to disable server non user files.

DocumentRoot /var/www

# UserDir: The name of the directory which is appended onto a user's home
# directory if a ~user request is received.

UserDir public_html

# DirectoryIndex: Name of the file to use as a pre-written HTML
# directory index.  Please MAKE AND USE THESE FILES.  On the
# fly creation of directory indexes can be _slow_.
# Comment out to always use DirectoryMaker

DirectoryIndex index.html

# DirectoryMaker: Name of program used to create a directory listing.
# Comment out to disable directory listings.  If both this and
# DirectoryIndex are commented out, accessing a directory will give
# an error (though accessing files in the directory are still ok).

DirectoryMaker /usr/lib/boa/boa_indexer

# DirectoryCache: If DirectoryIndex doesn't exist, and DirectoryMaker
# has been commented out, the the on-the-fly indexing of Boa can be used
# to generate indexes of directories. Be warned that the output is 
# extremely minimal and can cause delays when slow disks are used.
# Note: The DirectoryCache must be writable by the same user/group that 
# Boa runs as.

# DirectoryCache /var/spool/boa/dircache

# KeepAliveMax: Number of KeepAlive requests to allow per connection
# Comment out, or set to 0 to disable keepalive processing

KeepAliveMax 1000

# KeepAliveTimeout: seconds to wait before keepalive connection times out

KeepAliveTimeout 10

# MimeTypes: This is the file that is used to generate mime type pairs
# and Content-Type fields for boa.
# Set to /dev/null if you do not want to load a mime types file.
# Do *not* comment out (better use AddType!)

MimeTypes /etc/mime.types

# DefaultType: MIME type used if the file extension is unknown, or there
# is no file extension.

DefaultType text/plain

# CGIPath: The value of the $PATH environment variable given to CGI progs.

CGIPath /bin:/usr/bin:/usr/local/bin

# SinglePostLimit: The maximum allowable number of bytes in 
# a single POST.  Default is normally 1MB.

# AddType: adds types without editing mime.types
# Example: AddType type extension [extension ...]

# Uncomment the next line if you want .cgi files to execute from anywhere
#AddType application/x-httpd-cgi cgi

# Redirect, Alias, and ScriptAlias all have the same semantics -- they
# match the beginning of a request and take appropriate action.  Use
# Redirect for other servers, Alias for the same server, and ScriptAlias
# to enable directories for script execution.

# Redirect allows you to tell clients about documents which used to exist in
# your server's namespace, but do not anymore. This allows you to tell the
# clients where to look for the relocated document.
# Example: Redirect /bar http://elsewhere/feh/bar

# Aliases: Aliases one path to another.
# Example: Alias /path1/bar /path2/foo

Alias /doc /usr/doc

# ScriptAlias: Maps a virtual path to a directory for serving scripts
# Example: ScriptAlias /htbin/ /www/htbin/

ScriptAlias /cgi-bin/ /usr/lib/cgi-bin/

BOA源码：

http://www.boa.org/

编译BOA源码：

#tar zxvf boa-0.94.14.tar.gz

#cd boa-0.94.tar.gz/src/

#./configure

#make

设置BOA配置信息

1.建立boa.conf配置文件的路径，并复制boa.conf文件到该目录下。

#mkdir /etc/toa

#cp boa.conf /etc/boa

2.建立日志目录/var/log/boa。

#mkdir /var/log/boa

3.修改配置信息：

#  User: The name or UID the server should run as.
# Group: The group name or GID the server should run as. 
User nobody
Group nogroup 改为 Group 0

 # CGIPath: The value of the $PATH environment variable given to CGI progs. 
CGIPath /bin:/usr/bin:/usr/local/bin  修改为：CGIPath /bin:/usr/bin:/var/lwww/cgi-bin

# DirectoryMaker: Name of program used to create a directory listing.
# Comment out to disable directory listings.  If both this and
# DirectoryIndex are commented out, accessing a directory will give
# an error (though accessing files in the directory are still ok). 
DirectoryMaker /usr/lib/boa/boa_indexer

# ScriptAlias: Maps a virtual path to a directory for serving scripts
# Example: ScriptAlias /htbin/ /www/htbin/ 
ScriptAlias /cgi-bin/ /usr/lib/cgi-bin/  修改为ScripAlias /cgi-bin/   /var/www/cgi-bin

# ServerName: the name of this server that should be sent back to  
# clients if different than that returned by gethostname + gethostbyname  
ServerName www.your.org.here

 测试BOA

1.编写测试主页index.html

<% page contentType="text/html; charset=gb2313" %》
<! DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<title> boa test page! </title>
<head><font color="#cc2200"><b></b>欢迎大家测试BOA服务器</font><p>
</head>
<body>
测试BOA服务器测试页。
</body>
</html>

2.启动Web服务器

#./boa

#ps