之前一直使用单个进程都php-cgi。存在一个很严重都问题就是，php-cgi不稳定导致程序异常退出时，需要外部程序重新启动php-cgi。而且因为socket还要等待一段时间才能断开，所以要等一段时间（大概30多秒）才能重新启动成功。这样就产生了一段时间无法使用php都网页，很是烦恼。之前就一直想写一个php-cgi都进程管理器。

现在服务器上运行了几个庞大的wordpress，php崩溃都机率又大多了，迫不得已去给homeserver安装一个进程管理器。我测试过使用php-fpm，但是不好使，一是占用内存非常大，二是出现突然间无法响应都现象。后来yousan大牛推荐了用于lighttpd都spawn-fcgi，我在windows测试成功了，终于可以并发处理多个php请求。测试方法是，写一个php文件，里面写，如果刷新两次等待了10秒，那么就说明没有并发处理功能。打开多个页面测试也可以。

我参考了lighttpd都源代码，得知到之前我一直无法手动启用多个php-cgi，是因为没有使用共享socket（或者设置socket的重用标记）。我给Windows和Linux写了不同的实现方式以支持不同平台都使用。不过，因为我对Windows上都权限处理不熟悉，所以没有写用户权限都切换功能。HomeServer是以root形式使用80端口运行的，但php总不能以root运行吧，那样脚本都权限就太大了。应该可以让人指定运行使用都用户和组（例如www-data）。

启动多个php-cgi都方法是，先创建一个socket，设置为可重用（REUSE标记）。然后创建多个线程（用于并发处理php脚本），把这个socket作为输入句柄传给新创建都php-cgi进程，然后线程等待php-cgi进程崩溃或异常退出，如果服务器还在运行，则重启php-cgi。

当HomeServer结束时，杀死所有的php-cgi进程。Linux下，如果父进程被Kill了，子进程都php-cgi也会退出吧，因为都是使用同一个会话，而HomeServer就是这个会话都主进程。对不？

废话少说，下面是对plugin_fcgi.c都扩展代码：

static void* spawn_process( void* data )
{
	FILE* fp;
	fcgi_program* fcgi = (fcgi_program*)data;
	int idx = fcgi->spawn_count ++, ret;
	while( !end ){
#ifdef __WIN32__
		STARTUPINFO si={0};
		PROCESS_INFORMATION pi={0};
		ZeroMemory(&si,sizeof(STARTUPINFO));
		si.cb = sizeof(STARTUPINFO);
		si.dwFlags = STARTF_USESTDHANDLES;
		si.hStdOutput = INVALID_HANDLE_VALUE;
		si.hStdInput  = (HANDLE)fcgi->listen_fd;
		si.hStdError  = INVALID_HANDLE_VALUE;
		if( 0 == (ret=CreateProcess(NULL, fcgi->shell,
			NULL,NULL,
			TRUE, CREATE_NO_WINDOW ,
			NULL,NULL,
			&si,&pi)) ){
			printf("[fcgi] failed to create process %s, ret=%d\n", fcgi->shell, ret);
			return NULL;
		}
		fcgi->process_fp[idx] = (int)pi.hProcess;
		printf("[fcgi] starting process %s\n", fcgi->shell );
		WaitForSingleObject(pi.hProcess, INFINITE);
		fcgi->process_fp[idx] = 0;
		CloseHandle(pi.hThread);
#else
		ret = fork();
		switch(ret){
		case 0:{	//child
			/* change uid from root to other user */
			if(getuid()==0){ 
                struct group *grp = NULL;
                struct passwd *pwd = NULL;
				if (*fcgi->username) {
					if (NULL == (pwd = getpwnam(fcgi->username))) {
						printf("[fcgi] %s %s\n", "can't find username", fcgi->username);
						exit(-1);
					}
					if (pwd->pw_uid == 0) {
						printf("[fcgi] %s\n", "what? dest uid == 0?" );
						exit(-1);
					}
				}
				if (*fcgi->groupname) {
					if (NULL == (grp = getgrnam(fcgi->groupname))) {
						printf("[fcgi] %s %s\n", "can't find groupname", fcgi->groupname);
						exit(1);
					}
					if (grp->gr_gid == 0) {
						printf("[fcgi] %s\n", "what? dest gid == 0?" );
						exit(1);
					}
					/* do the change before we do the chroot() */
					setgid(grp->gr_gid);
					setgroups(0, NULL);
					if (fcgi->username) {
						initgroups(fcgi->username, grp->gr_gid);
					}
				}
				if (*fcgi->changeroot) {
					if (-1 == chroot(fcgi->changeroot)) {
						printf("[fcgi] %s %s\n", "can't change root", fcgi->changeroot);
						exit(1);
					}
					if (-1 == chdir("/")) {
						printf("[fcgi] %s %s\n", "can't change dir to", fcgi->changeroot);
						exit(1);
					}
				}
				/* drop root privs */
				if (*fcgi->username) {
					printf("[fcgi] setuid to %s\n", fcgi->username);
					setuid(pwd->pw_uid);
				}
			}
			
			int max_fd = 0, i=0;
			// Set stdin to listen_fd
			close(STDIN_FILENO);
			dup2(fcgi->listen_fd, STDIN_FILENO);
			close(fcgi->listen_fd);
			// Set stdout and stderr to dummy fd
			max_fd = open("/dev/null", O_RDWR);
			close(STDERR_FILENO);
			dup2(max_fd, STDERR_FILENO);
			close(max_fd);
			max_fd = open("/dev/null", O_RDWR);
			close(STDOUT_FILENO);
			dup2(max_fd, STDOUT_FILENO);
			close(max_fd);
			// close other handles
			for(i=3; i<max_fd; i++)
				close(i);
			char *b = malloc(strlen("exec ") + strlen(fcgi->shell) + 1);
			strcpy(b, "exec ");
			strcat(b, fcgi->shell);
			
			/* exec the cgi */
			execl("/bin/sh", "sh", "-c", b, (char *)NULL);
			exit(errno);
			break;
		}
		case -1:
			printf("[fcgi] fork failed\n");
			return NULL;
		default:{
			struct timeval tv = { 0, 100 * 1000 };
			int status;
			select(0, NULL, NULL, NULL, &tv);
			switch(waitpid(ret, &status, WNOHANG)){
			case 0:
				printf("[fcg] spawned process %s: %d\n", fcgi->shell, ret);
				break;
			case -1:
				printf("[fcgi] waitpid failed\n");
				return NULL;
			default:
				if (WIFEXITED(status)) {
						printf("[fcgi] child exited with: %d\n", WEXITSTATUS(status));
				} else if (WIFSIGNALED(status)) {
						printf("[fcgi] child signaled: %d\n", WTERMSIG(status));
				} else {
						printf("[fcgi] child died somehow: %d\n", status);
				}
				return NULL;
			}
			//wait for child process to exit
			fcgi->process_fp[idx] = ret;
			waitpid(ret, &status, 0);
			fcgi->process_fp[idx] = 0;
		}
		}
#endif
	}
	if(!end){
		printf("[fcgi] failed to create process %s\n", fcgi->shell );
	}
	return NULL;
}

static void delete_program( const void* v )
{
	fcgi_program * fp = (fcgi_program*)v;
	int i;
	for( i=0; i<fp->spawn_count; i++ ){
		if( fp->process_fp[i] ){
			int h = fp->process_fp[i];
			printf("[fcgi] terminating %s: %x\n", fp->shell, h );
#ifdef __WIN32__
			TerminateProcess((HANDLE)h, 0);
#else
			kill(fp->process_fp[i], SIGKILL);
#endif
//			pthread_join( fp->threads[i], (void**)0 );
		}
	}
	closesocket( fp->listen_fd );
	free( fp );
}

#ifdef __WIN32__
#define EXPORT __declspec(dllexport) __stdcall 
#else
#define EXPORT
#endif
int EXPORT plugin_entry( webserver* srv )
{
	pthread_attr_t attr;
	pthread_attr_init(&attr);
	pthread_attr_setstacksize(&attr, 64*1024); //64KB
	//load fcgi program information
	loop_create( &loop_program, MAX_FCGI_PROGRAM, delete_program );
	if( xml_redirect( srv->config, "/fastCGI/program", 0 ) ){
		do{
			int spawn_count, i;
			fcgi_program * fcgip;
			fcgip = (fcgi_program*) malloc( sizeof(fcgi_program) );
			memset( fcgip, 0, sizeof(fcgi_program) );
			loop_push_to_head( &loop_program, (void*)fcgip );
			strncpy( fcgip->extension, xml_readstr(srv->config, ":extension"), 63 );
			strncpy( fcgip->username, xml_readstr( srv->config, "spawnProcess:user" ), 31 );
			strncpy( fcgip->groupname, xml_readstr( srv->config, "spawnProcess:group" ), 31 );
			strncpy( fcgip->changeroot, xml_readstr( srv->config, "spawnProcess:root" ), 127 );
			strncpy( fcgip->shell, xml_readstr( srv->config, "spawnProcess:path" ), 127 );
			spawn_count = xml_readnum(srv->config, "spawnProcess:number");
			strncpy( fcgip->server_addr, xml_readstr( srv->config, "serverAddress" ), 63 );
			fcgip->server_port = xml_readnum(srv->config, "serverPort");
			printf("[fcgi] fcgi for %s:%d extension:%s shell:%s\n", fcgip->server_addr, fcgip->server_port, 
				fcgip->extension, fcgip->shell );
			fcgip->dest_addr.sin_family = PF_INET;
			fcgip->dest_addr.sin_addr.s_addr = inet_addr( fcgip->server_addr );
			fcgip->dest_addr.sin_port = htons( fcgip->server_port );
			
			/* Check If we need to start the fastcgi process */
			if( fcgip->shell[0] ){
				fcgip->listen_fd = socket(AF_INET, SOCK_STREAM, 0);
				
				if( connect( fcgip->listen_fd, (struct sockaddr*)&fcgip->dest_addr, sizeof(struct sockaddr_in)) != -1 ){
					printf("[fcgi] %s:%d is already in use. failed to spawn in.\n", fcgip->server_addr, fcgip->server_port );
					closesocket( fcgip->listen_fd );
					return -1;
				}
				closesocket( fcgip->listen_fd );
				//reopen socket
				fcgip->listen_fd = socket(AF_INET, SOCK_STREAM, 0);
				i = 1;
				setsockopt( fcgip->listen_fd, SOL_SOCKET, SO_REUSEADDR, (void*)&i, sizeof(i));
				
				if (-1 == bind( fcgip->listen_fd, (struct sockaddr*)&fcgip->dest_addr, sizeof(struct sockaddr_in)) ) {
					printf("[fcgi] failed to bind %s:%d\n", fcgip->server_addr, fcgip->server_port );
					return -1;
				}
				listen(fcgip->listen_fd, srv->max_threads);
				if( spawn_count < 1 || spawn_count > 64 )
					spawn_count = 5;
				for( i=0; i<spawn_count; i++ )
					if( pthread_create( &fcgip->threads[i], &attr, (void*)spawn_process, (void*)fcgip ) == -1 ){
						printf("[fcgi] failed to create thread: %d\n", errno);
					}
			}
		}while( xml_movenext( srv->config ) );
	}
	srv->vdir_create( srv, "/", (vdir_handler)fcgi_run );
	return 0;
}

int EXPORT plugin_cleanup( webserver* srv )
{
	end = 1;
	loop_cleanup( &loop_program );
	return 0;
}

如有错误或更好都提议，不妨提出来共同讨论。