Starting another process from php

dick99

I'm transferring all my old LP's to a 40 GB hard drive on my Linux server system (Red Hat 7.0) at home. I want to access it using a web page, and have built a MySQL database to hold information about the albums, including the path to the .mp3 file. I display the list of music, and have a link to the .mp3 file so that any browser in the house can play a recording. I also have a link to click that is supposed to start playing the recording on the server's sound card, the output of which is connected to the stereo in the living room.

It's supposed to, but it isn't working. I pass the name of the .mp3 file to play to another .php page like this:

<A HREF="PlayOnStereo.php?MDirectory=<?$Md?>&MFile=<?=$Mf?>">*</A>

PlayOnStereo.php consists of the following:

<p>Now playing <?=$MFile?>
<?
$PthName = $MDirectory . $MFile;
system("/usr/bin/mpg123 $PthName");
?>

When I click on the asterisk, I get a new page that says, "Now playing" followed by the name of the .mp3 file, but the song doesn't play.

Suggestions?

Thanks.

Regards,

Dick Steffens

vsego

I'm not too experienced on Unix, but have you tried leaving it in the background?

system("/usr/bin/mpg123 $PthName &");
or
system("nohup /usr/bin/mpg123 $PthName &");

Anon

Have you checked that everything works from the shell, and that it does so when logged in as 'nobody'? You can test this, even though 'nobody' can't log in directly, by going through root first (at least with 6.x, don't have ready access to 7.1 to test it there):

  
  Red Hat Linux release 6.1 (Cartman)
  Kernel 2.2.12-20 on an i586
  login: serf
  Password:
  Last login: Fri Oct 5 22:52:32 from 10.0.0.39
  [serf@system serf]$ su -
  Password:
  [root@system /root]# su nobody

I omitted '-' so it wouldn't run profiles, thus I stay in /root as my current directory. And lo, I'm really logged in with nobody's permission:

  [nobody@system /root]$ ls
  ls: .: Permission denied
  [nobody@system /root]$

dick99

Neither of those made any difference. I had fogotten about putting the & at the end to run in the background. Not that you mention it, I remember reading about it, though. Thanks for the reminder.

dick99

I had a feeling it might be a permissions thing. No, I hadn't tried su'ing as nobody. Never occurred to me!

OK. I tried that and I get:

//.esd_auth: Permission denied
//.esd_auth: Permission denied
//.esd_auth: Permission denied
audio: Permission denied

[1]+ Done(1) mpg123 Track_01.MP3

So, time for some more System Administration training. What do I need to do for nobody? I assume nobody needs x rights, someplace, but where? And is that all?

Thanks for the help.

Anon

What exactly is 'usr/bin/mpg123'? If it's a shell script, you can look at it and see what it's doing; if it's a binary executable you'll have to search the docs. One thing for sure: it appears 'nobody' doesn't have rights to open 'audio'.

dick99

mpg123 is an executable. It is a program for playing .mp3 files through the sound card on a Linux machine.

You're right. I need to learn more about assigning rights to things like audio in a web setting. I could just find out what to change and give everyone all rights to it, but I'd rather learn the "preferred" way to handle requests from web users.