如何以 root 身份使用pulseaudio API? [英] How to use the pulseaudio API as root?

问题描述

我目前正在尝试使用 pulseaudio 简单 API 来录制麦克风来自我的 USB 声卡和树莓派 3 的数据.我使用了示例程序 parec-simple 来自我自己程序中的pulseaudio，效果很好.

I am currently trying to use the pulseaudio simple API to record microphone data from my USB sound card with my raspberry pi 3. I used the example program parec-simple from pulseaudio in my own program and it works quite nice.

我使用此代码的程序正在访问 gpio，因此我需要以 root 身份运行它.但是，当我尝试以 root 身份执行程序时，出现以下错误:

The program i used this code for is accessing gpio's so i need to run this as root. However, when i try to execute the program as root, i get the following errors:

Home directory not accessible: Permission denied
W: [pulseaudio] core-util.c: Failed to open configuration file '/root/.config/pulse//daemon.conf': Permission denied
W: [pulseaudio] daemon-conf.c: Failed to open configuration file: Permission denied
pa_simple_new() failed: Connection refused

使用的代码如下:

static const pa_sample_spec ss = {
    .format = PA_SAMPLE_S16LE,
    .rate = 44100,
    .channels = 1
};
pa_simple *s = NULL;
int ret = 1;
int error;
/* Create the recording stream */
if (!(s = pa_simple_new(NULL, argv[0], PA_STREAM_RECORD, NULL, "record", &ss, NULL, NULL, &error))) {
    fprintf(stderr, "pa_simple_new() failed: %s\n", pa_strerror(error));
    goto finish;
}



while(1)
{
    uint8_t buf[BUFSIZE];
    /* Record some data ... */
    if (pa_simple_read(s, buf, sizeof(buf), &error) < 0) {
        fprintf(stderr, __FILE__": pa_simple_read() failed: %s\n", pa_strerror(error));
        goto finish;
    }

    /* And write it to STDOUT */
    if (loop_write(STDOUT_FILENO, buf, sizeof(buf)) != sizeof(buf)) {
        fprintf(stderr, __FILE__": write() failed: %s\n", strerror(errno));
        goto finish;
    }

}
   ret = 0;
finish:
    if (s)
        pa_simple_free(s);
    return ret;

我已经按照此处的建议尝试了chown pi:pi/home/pi 尝试修复它，但它不起作用.将/home/pi 的所有者从 pi 更改为 root 对我也不起作用.

I already tried chown pi:pi /home/pi as suggested here to try to fix it but it doesn't work. changing the owner of /home/pi from pi to root didn't work for me either.

我也尝试干净地重新安装pulseaudio，但不幸的是它没有修复它.

I also tried a clean reinstall of pulseaudio but unfortunately it didn't fix it.

那么我该怎么做才能修复这些错误?

So what can i do to fix these errors?

推荐答案

如果您需要以 root 用户身份运行您的程序，那么您必须模拟 root.我不知道 pulseaudio 是查看用户名以查找配置文件，还是查看 $HOME 变量.在第二种情况下，也许将 HOME 设置为工作"用户的家会有所帮助.

If you need to run your program as user root, then you must impersonate root. I don't know if pulseaudio looks at the username in order to find configuration files, or it looks at the $HOME variable. In the second case, maybe that by setting HOME to the home of a "working" user helps.

不管怎样，你说的情况很清楚:pulseaudio没有找到文件:

Anyway what you told about the situation is clear: pulseaudio does not find a file:

'/root/.config/pulse//daemon.conf'

'/root/.config/pulse//daemon.conf'

在那个目录中放置一个正确的daemon.conf"——也许你可以从某个地方复制它(比如/home/auser/.config/pulse/daemon.conf).

Place a correct "daemon.conf" in that directory - probably you can copy it from somewhere (like /home/auser/.config/pulse/daemon.conf).

考虑到名称以点开头的目录通常是隐藏的；如果使用文件管理器，您必须启用显示隐藏文件"，如果您使用 shell，ls -a 可以提供帮助.

Consider that directories with name starting with a dot are normally hidden; if using a file manager you must enable "show hidden files", if you use the shell, ls -a can help.

你的第一个目标是确认文件在那里，你的程序不应该抱怨丢失/不可读的配置文件.然后，也许会出现其他错误，但您可以一个接一个地消除它们.

Your first target is to confirm that the file is there, and your program should not complain about a missing/unreadable config file. Then, maybe other errors will show up but, one after another, you can eliminate them.

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