轻量级服务器tinyhttpd源码分析－本地运行
20 June 2015
从sourceforge上下载源码到本地，我在看源码之前喜欢先将程序运行起来看下程序运行的效果，这样对于程序的功能先有一个感性的认识。
下载下来的源码是在Solaris 2.6上编译运行的，在httpd.c中写道：在如果你想要在Linux上运行的话，需要进行一些修改：
1) 注释掉 #include <pthread.h>
2) 注释掉newthread变量的定义
3) 注释掉pthread_create()函数的调用
4) 将accept_request()的调用取消注释
5) 在Makefile中移除-lsocket 修改完之后Server变成了单线程的程序，只能够一个客户端进行连接，所以决定不按照上面的修改，本机的运行环境：OS X。首先将程序make下看看有什么错误。
httpd.c:437:52: warning: passing 'int *' to parameter of type 'socklen_t *' (aka 'unsigned int *') converts between pointers to integer types with different
sign [-Wpointer-sign]
if (getsockname(httpd, (struct sockaddr *)&name, &namelen) == -1)
^~~~~~~~
/usr/include/sys/socket.h:566:74: note: passing argument to parameter here
int getsockname(int, struct sockaddr * __restrict, socklen_t * __restrict)
^
httpd.c:491:24: warning: passing 'int *' to parameter of type 'socklen_t *' (aka 'unsigned int *') converts between pointers to integer types with different
sign [-Wpointer-sign]
&client_name_len);
^~~~~~~~~~~~~~~~
/usr/include/sys/socket.h:560:69: note: passing argument to parameter here
int accept(int, struct sockaddr * __restrict, socklen_t * __restrict)
^
httpd.c:495:40: warning: incompatible pointer types passing 'void (int)' to parameter of type 'void *(*)(void *)' [-Wincompatible-pointer-types]
if (pthread_create(&newthread , NULL, accept_request, client_sock) != 0)
^~~~~~~~~~~~~~
/usr/include/pthread.h:314:11: note: passing argument to parameter here
void *(*)(void *), void * __restrict);
^
httpd.c:495:56: warning: incompatible integer to pointer conversion passing 'int' to parameter of type 'void *' [-Wint-conversion]
if (pthread_create(&newthread , NULL, accept_request, client_sock) != 0)
^~~~~~~~~~~
/usr/include/pthread.h:314:39: note: passing argument to parameter here
void *(*)(void *), void * __restrict);
^
4 warnings generated.有四个警告，让我们一一解决掉，首先是：
httpd.c:437:52: warning: passing 'int *' to parameter of type 'socklen_t *' (aka 'unsigned int *') converts between pointers to integer types with different这个警告的意思就是getsockname函数的第三个参数应该是socklen_t *类型，但是实际传入的参数类型是int *类型，只需要修改下namelen定义的类型修改为socklen_t类型。
httpd.c:491:24: warning: passing 'int *' to parameter of type 'socklen_t *' (aka 'unsigned int *') converts between pointers to integer types with different这个错误与上面错误类似，也是类型不匹配，将client_name_len定义为socklen_t类型就好了。
httpd.c:495:40: warning: incompatible pointer types passing 'void (int)' to parameter of type 'void *(*)(void *)' [-Wincompatible-pointer-types]这个错误也是参数类型不匹配，pthread_create函数的第三个参数是函数指针类型，这个函数指针应该是void ()(void *)类型，但是定义的accept_request声明为；
void accept_request(int); 所以需要对accept_request进行一些修改，首先将accept_request声明为：
void *accept_request(void *); 因为参数类型和函数返回值都改变了，所以在函数内部需要做些改动，在client使用之前将ptr_client转为client，还有就是需要在最后增加返回语句return NULL;，在中间需要返回的时候也需要返回NULL，修改完的accept_request代码如下：
void *accept_request(void *pclient)
{
char buf[1024];
int numchars;
char method[255];
char url[255];
char path[512];
size_t i, j;
struct stat st;
int cgi = 0; /* becomes true if server decides this is a CGI program */
char *query_string = NULL;
size_t client = *(size_t *)pclient;
numchars = get_line(client, buf, sizeof(buf));
i = 0; j = 0;
while (!ISspace(buf[j]) && (i < sizeof(method) - 1))
{
method[i] = buf[j];
i++; j++;
}
method[i] = '\0';
if (strcasecmp(method, "GET") && strcasecmp(method, "POST"))
{
unimplemented(client);
return NULL;
}
if (strcasecmp(method, "POST") == 0)
cgi = 1;
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';
if (strcasecmp(method, "GET") == 0)
{
query_string = url;
while ((*query_string != '?') && (*query_string != '\0'))
query_string++;
if (*query_string == '?')
{
cgi = 1;
*query_string = '\0';
query_string++;
}
}
sprintf(path, "htdocs%s", url);
if (path[strlen(path) - 1] == '/')
strcat(path, "index.html");
if (stat(path, &st) == -1) {
while ((numchars > 0) && strcmp("\n", buf)) /* read & discard headers */
numchars = get_line(client, buf, sizeof(buf));
not_found(client);
}
else
{
if ((st.st_mode & S_IFMT) == S_IFDIR)
strcat(path, "/index.html");
if ((st.st_mode & S_IXUSR) ||
(st.st_mode & S_IXGRP) ||
(st.st_mode & S_IXOTH) )
cgi = 1;
if (!cgi)
serve_file(client, path);
else
execute_cgi(client, path, method, query_string);
}
close(client);
return NULL;
} 再将-lsocket从Makefile中删去即可。
最后，还有一处错误需要修改：
execl(path, path, NULL); 改为
execl(path, query_string, NULL); 再次运行make，没有警告了，运行可执行文件httpd：./ httpd，显示程序在哪个端口监听，打开浏览器，输入127.0.0.1:<端口号>，页面如图所示：  在框中输入red或者blue，点击按钮跳转，跳转之后的页面显示为你填写的颜色：  经过上述的修改tinyhttpd便能在本地运行起来了，接下来对它的源码进行简要的分析。