Small embedded system, need working ntpd...

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- Mark
  
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posted
18 years ago

Wed, Jun 8, 2005 10:40 PM

I have a small embedded system (pc/104 board, CF-boot, read-only root file system, etc). I am trying to get a ntp daemon to work to keep the time accurate. I downloaded and compiled (on the same hardware but booting off a HD, which has more space, and is a 'normal' gentoo system) openntpd

formatting link

however I am having trouble getting it to work.

There seems to be almost no documentation with it, nothing that really explains how to get it to work.

I ran the file (./ntpd) and it said it couldn't find a file, /etc/ntpd.conf, I then created that file, then ran it again, now it says "unknown user _ntp". I have a "_ntp" user and a "ntp" user (one of my linux gurus said it would not be _ntp, another said it would be _ntp, so I'm confused). In either case it doesn't work, gives me the "unknown user _ntp" and that's as far as I get.

Anyone used this ntpd, and if not, anyone have another simple, small ntpd I could throw into this project.

TIA, Mark Brodis

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- Darren Tucker
  
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posted
18 years ago

Sun, Jun 26, 2005 9:01 AM

Someone else emailed me about that today, also for an embedded system. (The "make install" process normally takes care of most installation tasks on self-hosted systems). The doco has been updated in the latest snapshot with the details (see the INSTALL file):

formatting link

It defaults to "_ntp" unless you overrode it at configure time with

--with-privsep-user=foo.

It's possible that the problem isn't in ntpd itself, eg if your flash filesystem is missing some of the components required for the getpwnam() function to work (eg /etc/nsswitch.conf or the libnss*.so files if you're using glibc).

Try the test program at the bottom of this post. If that doesn't work either then you need to take a closer look at your system.

$ ./a.out _ntp home dir = /var/empty/ntpd $ ./a.out root home dir = /root

Well, it works for me :-) I have used it on an embedded Linux firewall/ router (300MHz Geode, 64MB RAM, 2.4 kernel, uClibc, busybox plus assorted other stuff).

[example program] #include #include #include

int main(int argc, char **argv) { struct passwd *pw;

if (argc != 2) { printf("usage: %s username\n", argv[0]); exit(0); } pw = getpwnam(argv[1]); if (pw == NULL) printf("getpwnam failed\n"); else printf("home dir = %s\n", pw->pw_dir); exit(0); }

--
Darren Tucker (dtucker at zip.com.au)
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    Good judgement comes with experience. Unfortunately, the experience
usually comes from bad judgement.

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- Mark
  
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posted
18 years ago

Thu, Jun 30, 2005 4:01 AM

Thanks for your response!

I had already figured out the majority of the problems, it was with some library conflicts....doh!! Once that was resolved, and I got some help from a brilliant embedded Linux guy, all fell into place... :)