linux/nohup/qt：从带有NOHUP的系统命令（非QT守护程序）启动外部QT程序不起作用

发布于 2025-01-31 17:48:47 字数 2481 浏览 2 评论 0 原文

在一个名为 tep2020gateway 的USB守护程序中，我有一个函数 swupdating （这正在更新我的应用程序： tep2020ihm ），通过使用通用工具 swupdate 。

在该更新守护程序 tep2020gateway 中：

首先，我停止应用程序 tep2020ihm
然后，我尝试启动一个名为 update_ivate_ihm 的小型QT应用程序，以显示进度栏我正在更新该应用程序。
最终，我启动 swupdate 来解决更新

问题： update_ihm 从未出现的进度栏从未出现，屏幕不会更改，好像没有启动update_ihm应用程序（或停止）立即立即键入命令（

尽管我键入命令（nohup/usr/bin/update_ihm＆lt;/dev/null），但酒吧出现。一切都很好。但是它无法从系统命令中起作用。

这是我的（简短）函数，希望它足够可读：

static void swUpdating(void) {

    syslog(LOG_INFO, "Stopping tep2020ihm and starting update_ihm");
    int rc = std::system("bash -c 'systemctl stop tep2020ihm; echo >nohup.out; (nohup /usr/bin/update_ihm </dev/null)&'");

    syslog(LOG_INFO, "%s %d : Starting Sw_update (stop tep2020ihm/start update_ihm returned rc=%d)", __PRETTY_FUNCTION__, __LINE__, rc);
    rc = std::system("bash -c '" SW_UPDATE " -k " PUBLIC_KEY " -K " AES_KEY " -i " DATA_FILE " >" LOG_FILE " 2>&1'");
    syslog(LOG_INFO, "%s %d : Sw_update starting returned code: %d", __PRETTY_FUNCTION__, __LINE__, rc);

    <...>

    unlink(DATA_FILE);
}

您可以看到该功能中有系统列表，我可以在日志中看到它们：

May 24 07:51:26 Tep2020-220 local1.info /usr/bin/tep2020gateway[187]: Stopping tep2020ihm and starting update_ihm
May 24 07:51:26 Tep2020-220 local1.notice /opt/pfd2020/tep2020ihm[207]: received signal #15
May 24 07:51:26 Tep2020-220 local1.notice /usr/bin/tep2020gateway[187]: received signal #17
May 24 07:51:26 Tep2020-220 local1.info /usr/bin/tep2020gateway[187]: void swUpdating() 72 : Starting Sw_update (stop tep2020ihm/start update_ihm returned rc=0)
May 24 07:51:26 Tep2020-220 user.debug swupdate: RUN [extract_sw_description] : Found file:     filename sw-description         size 596       checksum 0x88ce VERIFIED
May 24 07:51:26 Tep2020-220 user.debug swupdate: RUN [extract_sw_description] : Found file:     filename sw-description.sig     size 256       checksum 0x7604 VERIFIED
May 24 07:51:26 Tep2020-220 user.debug swupdate: RUN [swupdate_verify_file] : Verify signed image: Read 596 bytes

edit：通过将平台添加到命令中来修复。当我将这个小的bargraph update_ihm 变成服务时，我收到了“丢失QT插件”的消息时，即平台缺少。这是修复的，我添加了它： update_ihm-platform linuxfb：fb =/dev/fb0

原文

Inside an USB daemon named tep2020gateway I've got a function swUPdating (that is updating my application: tep2020ihm) by using the generic tool swupdate.

Inside that updater daemon tep2020gateway :

First I stop the application tep2020ihm
Then I try to start a small Qt application named update_ihm to display a progress bar while I'm updating the app.
Eventually I launch swupdate to do the updating

PROBLEM: the progress bar supplied by update_ihm never appears, the screen does not change, as if the update_ihm app was not started (or stopped immediately despite the nohup)

If I type the command (nohup /usr/bin/update_ihm </dev/null)& in a console, that works: the progress bar shows up. Everything works fine. But it does not work from the system command.

Here is my (short) function, I hope it's readable enough:

static void swUpdating(void) {

    syslog(LOG_INFO, "Stopping tep2020ihm and starting update_ihm");
    int rc = std::system("bash -c 'systemctl stop tep2020ihm; echo >nohup.out; (nohup /usr/bin/update_ihm </dev/null)&'");

    syslog(LOG_INFO, "%s %d : Starting Sw_update (stop tep2020ihm/start update_ihm returned rc=%d)", __PRETTY_FUNCTION__, __LINE__, rc);
    rc = std::system("bash -c '" SW_UPDATE " -k " PUBLIC_KEY " -K " AES_KEY " -i " DATA_FILE " >" LOG_FILE " 2>&1'");
    syslog(LOG_INFO, "%s %d : Sw_update starting returned code: %d", __PRETTY_FUNCTION__, __LINE__, rc);

    <...>

    unlink(DATA_FILE);
}

You can see there are syslogs in the function, I can see them in the logs:

May 24 07:51:26 Tep2020-220 local1.info /usr/bin/tep2020gateway[187]: Stopping tep2020ihm and starting update_ihm
May 24 07:51:26 Tep2020-220 local1.notice /opt/pfd2020/tep2020ihm[207]: received signal #15
May 24 07:51:26 Tep2020-220 local1.notice /usr/bin/tep2020gateway[187]: received signal #17
May 24 07:51:26 Tep2020-220 local1.info /usr/bin/tep2020gateway[187]: void swUpdating() 72 : Starting Sw_update (stop tep2020ihm/start update_ihm returned rc=0)
May 24 07:51:26 Tep2020-220 user.debug swupdate: RUN [extract_sw_description] : Found file:     filename sw-description         size 596       checksum 0x88ce VERIFIED
May 24 07:51:26 Tep2020-220 user.debug swupdate: RUN [extract_sw_description] : Found file:     filename sw-description.sig     size 256       checksum 0x7604 VERIFIED
May 24 07:51:26 Tep2020-220 user.debug swupdate: RUN [swupdate_verify_file] : Verify signed image: Read 596 bytes

EDIT: this was fixed by adding the platform to the command.
When I turned this small bargraph update_ihm into a service I got the message "Missing Qt plugin", i.e. the platform was missing. This was fixed my adding it:
update_ihm --platform linuxfb:fb=/dev/fb0