如何从用户定义的引导时间守护程序服务器运行GUI应用程序

Question

我正在编写一个简单的服务器守护进程，并与/etc/init.d/server一起运行，它运行正常，但当我想用system()函数运行一个简单的QT GUI时，它无法运行它并返回256作为返回码。

如果同样的守护进程I正从终端运行，那么它工作正常，system()函数也成功，返回值为0，并且GUI弹出。

我不明白的问题是什么……plzzzz任何人都能帮助我..........

我正在使用ubuntu-9.10，下面是代码……

#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <syslog.h>

int main()
{
    //local variables
int sockfd,clifd,ret;
int client_flag = 0;
int server_flag = 1;
struct sockaddr_in server_addr,client_addr;
socklen_t client_len ;
int server_len;

daemon(0, 0);


/* open log file */
setlogmask(LOG_UPTO(LOG_INFO));
openlog("server:", LOG_CONS | LOG_PID, LOG_LOCAL2);


//creating the socket
sockfd = socket(AF_INET, SOCK_STREAM, 0);
if(sockfd < 0){
perror("Error socket creation:");
return sockfd;
}

//filling the socket address detail

server_addr.sin_family = AF_INET;
server_addr.sin_port = htons(8181);
server_addr.sin_addr.s_addr = inet_addr("127.0.0.1");
server_len = sizeof(server_addr);

//binding the socket
ret = bind(sockfd, (struct sockaddr *)&server_addr,server_len);
if(ret < 0){
perror("Error in bind");
return ret;
}

//creating the listening queue
ret = listen(sockfd, 10);
if(ret < 0){
perror("Error in listen");
return ret;
}

while(1){
//accepting the connection from client

client_len = sizeof(client_addr);
clifd = accept(sockfd, (struct sockaddr *)&client_addr, &client_len);
if(clifd < 0){
perror("Error in accept in server_init ");
return clifd;
}

client_flag = 0;

//reading the client_flag
ret = read(clifd, &client_flag,sizeof(client_flag));
if(ret < 0){
perror("Error in read");
return ret;
}

// if flag is true i want to run the GUI "console"
//console is Qt4 application
if(client_flag) {
syslog(LOG_NOTICE," *************** \n");

/* Here its returning 256 is if it is running from boot time and if after boot i will restrat it from terminal like "/etc/init.d/server restart" then it will return 0 success and GUI will popped up properly.*/

ret = system("/usr/sbin/test/console 1") ;

syslog(LOG_NOTICE," *************** %d\n",ret);


}
//writing the server_flag
ret = write(clifd, &server_flag,sizeof(server_flag));
if(ret < 0){
perror("Error in write");
return ret;
}


close(clifd);
}

closelog();
close(sockfd);
return 0;

}

Answer 1

请勿从引导运行图形应用程序。他们将无法访问X服务器。运行一个无头守护进程，并编写一个GUI应用程序来与其交互，该应用程序在GUI登录时启动。

Answer 2

对于服务器端，使用QtCoreApplication。可能有一些现成的解决方案来支持基于Qt的守护进程：

http://qt.nokia.com/products/appdev/add-on-products/catalog/4/Utilities/qtservice/