版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/renchunlin66/article/details/52371820
#include "httpd.h"
void usage(const char *proc)
{
printf("Usage : %s [PORT]\n", proc);
}
static void not_found(int client)
{
}
void print_debug(const char * msg)
{
#ifdef _DEBUG_
printf("%s\n", msg);
#endif
}
static void bad_request(int client)
{
print_debug("enter our fault...\n");
char buf[1024];
sprintf(buf, "HTTP/1.0 400 BAD REQUEST\r\n");
send(client, buf, strlen(buf), 0);
sprintf(buf, "Content-type: text/html\r\n");
send(client, buf, strlen(buf), 0);
sprintf(buf, "\r\n");
send(client, buf, strlen(buf), 0);
sprintf(buf, "<html></br><p>your enter message is a bad request</p></br></html>\r\n");
send(client, buf, strlen(buf), 0);
}
void print_log(const char *fun, int line, int err_no, const char *err_str)
{
printf("[%s: %d] [%d] [%s]\n", fun, line, err_no, err_str);
}
void clear_header(int client)
{
char buf[1024];
memset(buf, '\0', sizeof(buf));
int ret = 0;
do{
ret = get_line(client, buf, sizeof(buf));
}while(ret > 0 && strcmp(buf, "\n") != 0 );
}
//return num char, success
//return <= 0, failed
int get_line(int sock, char *buf, int max_len)
{
if( !buf || max_len < 0){
return -1;
}
int i = 0;
int n = 0;
char c = '\0';
while( i < max_len-1 && c != '\n' ){
n = recv(sock, &c, 1, 0);
if(n > 0){//success
if( c == '\r' ){
n = recv(sock, &c, 1,MSG_PEEK);
if( n > 0 && c == '\n' ){//windows
recv(sock, &c, 1, 0);//delete
}else{
c = '\n';
}
}
buf[i++] = c;
}else{//failed
c = '\n';
}
}
buf[i] = '\0';
return i;
}
void echo_error_to_client(int client, int error_code)
{
switch(error_code){
case 400://request error
bad_request(client);
break;
case 404://not found
not_found(client);
break;
case 500://server error
// server_error(client);
break;
case 503://server unavailable
// server_unavailable(client);
break;
//.....................
default:
// default_error(client);
break;
}
}
void echo_html(int client, const char *path, unsigned int file_size)
{
if( !path ){
return;
}
int in_fd = open(path, O_RDONLY);//以只读的形式打开
if(in_fd < 0){
print_debug("open index.html error");
//echo_error_to_client();
return;
}
print_debug("open index.html success");
char echo_line[1024];
memset(echo_line, '\0', sizeof(echo_line));
strncpy(echo_line, HTTP_VERSION, strlen(HTTP_VERSION)+1);
strcat(echo_line, " 200 OK");
strcat(echo_line, "\r\n\r\n");
send(client, echo_line,strlen(echo_line), 0);
print_debug("send echo head success");
if( sendfile(client, in_fd, NULL, file_size) < 0 ){
print_debug("send_file error");
//echo_error_to_client();
close(in_fd);
return;
}
print_debug("sendfile success");
close(in_fd);
}
void exe_cgi(int sock_client, const char *path, const char *method,const char *query_string)
{
print_debug("enter cgi\n");
char buf[_COMM_SIZE_];
int numchars = 0;
int content_length = -1;
//pipe
int cgi_input[2] = {0, 0};
int cgi_output[2] = {0, 0};
//child proc
pid_t id;
print_debug(method);
if(strcasecmp(method, "GET") == 0){//GET
clear_header(sock_client);
}else{//POST
do{
memset(buf, '\0', sizeof(buf));
numchars = get_line(sock_client, buf, sizeof(buf));
if(strncasecmp(buf, "Content-Length:", strlen("Content-Length:")) == 0){
//函数定义：int strncasecmp(const char *s1, const char *s2, size_t n)
//函数说明：strncasecmp()用来比较参数s1和s2字符串前n个字符，比较时会自动忽略大小写的差异。
content_length = atoi(&buf[16]);
}
}while(numchars > 0 && strcmp(buf, "\n") != 0);//一行一行的比较直到寻找content_length
if( content_length == -1 ){
//echo_error_to_client();
return;
}
}
memset(buf, '\0', sizeof(buf));
strcpy(buf, HTTP_VERSION);
strcat(buf, " 200 OK\r\n\r\n");
send(sock_client, buf, strlen(buf), 0);
if( pipe(cgi_input) == -1 ){//pipe error
//echo_error_to_client();
return;
}
if( pipe(cgi_output) == -1 ){
close(cgi_input[0]);
close(cgi_input[1]);
//echo_error_to_client();
return;
}
if( (id = fork()) < 0){//fork error
close(cgi_input[0]);
close(cgi_input[1]);
close(cgi_output[0]);
close(cgi_output[1]);
//echo_error_to_client();
return;
}else if( id == 0 ){//child
char query_env[_COMM_SIZE_/10];
char method_env[_COMM_SIZE_];
char content_len_env[_COMM_SIZE_];
memset(method_env, '\0', sizeof(method_env));
memset(query_env, '\0', sizeof(query_env));
memset(content_len_env, '\0', sizeof(content_len_env));
close(cgi_input[1]);
close(cgi_output[0]);
//redir
dup2(cgi_input[0], 0);
dup2(cgi_output[1], 1);
sprintf(method_env, "REQUEST_METHOD=%s", method);
putenv(method_env);
if(strcasecmp("GET", method) == 0){//POST
sprintf(query_env, "QUERY_STRING=%s", query_string);
putenv(query_env);
}else{//POST
sprintf(content_len_env, "CONTENT_LENGTH=%d", content_length);
putenv(content_len_env);
}
execl(path, path, NULL);//exec函数族
exit(1);
}else{//father
close(cgi_input[0]);
close(cgi_output[1]);
int i = 0;
char c = '\0';
if(strcasecmp("POST", method) == 0){
for(; i < content_length; i++ ){
recv(sock_client, &c, 1, 0);
write(cgi_input[1], &c, 1);
}
}
while( read(cgi_output[0], &c, 1) > 0 ){
send(sock_client, &c, 1, 0);
}
close(cgi_input[1]);
close(cgi_output[0]);
waitpid(id, NULL, 0);
}
}
//GET && POST
void *accept_request(void *arg)//这个arg实际上是由socket强转过来的那个参数
{
print_debug("get a new connect...\n");
pthread_detach(pthread_self());//detach //let the thread free automaticaly
int sock_client = (int)arg;//将客户端套接字恢复回来
//for test
//echo_error_to_client(sock_client, 400);
//close(sock_client);
//return;
int cgi = 0;
char *query_string = NULL;
char method[_COMM_SIZE_/10];
char url[_COMM_SIZE_];
char buffer[_COMM_SIZE_];
char path[_COMM_SIZE_];
memset(method, '\0', sizeof(method));
memset(url, '\0', sizeof(url));
memset(buffer, '\0', sizeof(buffer));
memset(path, '\0', sizeof(path));
//#ifdef _DEBUG_
// //success > 0
// //else <= 0
// while(get_line(sock_client, buffer, sizeof(buffer)) > 0){
// printf("%s", buffer);
// fflush(stdout);
// }
// printf("\n");
//#endif
if(get_line(sock_client, buffer, sizeof(buffer)) < 0){//从客户端一行一行读取数据
//echo_error_to_client();
return NULL;
}
int i = 0;
int j = 0;//buffer line index
while( !isspace(buffer[j]) &&\//从消息中获取方法保存到method
i < sizeof(method)-1 &&\
j < sizeof(buffer)){
method[i] = buffer[j];
i++, j++;
}
if( strcasecmp(method, "GET") && strcasecmp(method, "POST")){
//echo_error_to_client();
return NULL;
}
//clear space point useful url start
while( isspace(buffer[j]) &&\//如果发现是空行就跳到下一行，指向url开始的地方
j < sizeof(buffer)){
j++;
}
//get url
i = 0;
while(!isspace(buffer[j]) &&\//获取url
i < sizeof(url)-1 &&\
j < sizeof(buffer)){
url[i] = buffer[j];
i++;j++;
}
print_debug(method);//打印方法和路径
print_debug(url);
if(strcasecmp(method, "POST") == 0){//如果是POST方法，就让cgi=1,是不是POST方法就直接可用呢
cgi = 1;
}
if(strcasecmp(method, "GET") == 0){//那我们就可以稍微处理一下啦
query_string = url;
while( *query_string != '?' && *query_string != '\0'){
query_string++;
}
if( *query_string == '?' ){//url = /XXX/XXX + arg
*query_string = '\0';
query_string++;
cgi = 1;
}
}
sprintf(path, "htdocs%s", url);//将url所在文件包装成路径保存在path中
if(path[strlen(path)-1] == '/'){
strcat(path, MAIN_PAGE);//最后在附上主页就好了
}
print_debug(path);
struct stat st;
if( stat(path, &st) < 0 ){ //failed, does not exist // stat()用来将参数path 所指的文件状态, 复制到参数st所指的结构中
print_debug("miss cgi");
clear_header(sock_client);
//echo_error_to_client();
}else{//file exist!
if(S_ISDIR(st.st_mode)){//如果是个目录文件追加/
strcat(path, "/");
strcat(path, MAIN_PAGE);
}else if(st.st_mode & S_IXUSR ||\
st.st_mode & S_IXGRP ||\
st.st_mode & S_IXOTH){ //文件S_IRUSR (S_IREAD) 00400 文件所有者具可读取权限
//S_IWUSR (S_IWRITE)00200 文件所有者具可写入权限
//S_IXUSR (S_IEXEC) 00100 文件所有者具可执行权限
cgi = 1;
}else{
//do nothing
}
if(cgi){
exe_cgi(sock_client, path, method, query_string);
}else{
clear_header(sock_client);
print_debug("begin enter our echo_html");
echo_html(sock_client, path, st.st_size);
}
}
close(sock_client);
return NULL;
}
//if success return sock
//else exit process
int start(short port)
{
int listen_sock = socket(AF_INET, SOCK_STREAM, 0);
if(listen_sock == -1){
print_log(__FUNCTION__, __LINE__, errno, strerror(errno));
exit(1);
}
//reuse port//定义一个地址空间
int flag = 1;
setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR, &flag, sizeof(flag));
struct sockaddr_in local;
local.sin_family = AF_INET;
local.sin_port = htons(port);//host -> net
local.sin_addr.s_addr = htonl(INADDR_ANY);
socklen_t len = sizeof(local);
//将地址空间和定义的套接字绑定在一起
if(bind(listen_sock, (struct sockaddr*)&local, len) == -1){
print_log(__FUNCTION__, __LINE__, errno, strerror(errno));
exit(2);
}
//不断监听处理套接字的请求
if(listen(listen_sock, _BACK_LOG_) == -1){
print_log(__FUNCTION__, __LINE__, errno, strerror(errno));
exit(3);
}
//监听成功后返回监听套接字
return listen_sock; //sucess
}
//./httpd port
int main(int argc, char *argv[])
{
if(argc != 2){
usage(argv[0]);
exit(1);
}
//daemon();
int port = atoi(argv[1]);
int sock = start(port);//listen socket
struct sockaddr_in client;
socklen_t len = 0;
while(1){
int new_sock = accept(sock, (struct sockaddr*)&client, &len);//这个返回的新的套接字称为链接套接字，不同客户端的请求返回的
//新socket自然不一样
if( new_sock < 0 ){//accept error
print_log(__FUNCTION__, __LINE__, errno, strerror(errno));
continue;
}
pthread_t new_thread;//一旦有请求就定义一个新的线程去解决问题
pthread_create(&new_thread, NULL, accept_request, (void*)new_sock);//转成void*后变成参数传给accept_request
}
return 0;
}