Is there a way to redirect syslog messages to stdout?

Question

I have an application that can run in two modes, either with a CLI, or as a daemon.

I am using syslog() for logging. However, when run in CLI mode I'd like all the logging, except those marked LOG_DEBUG, messages to be sent to the console instead of logged.

I have tried to use setlogmask(), but that doesn't seem to redirect to console.

What is the best way to do this?

AFAIK, FreeBSD's syslog allows redirecting through /etc/syslog.conf. Anyway, it is not a way you're looking for. I suggest to write function that will detects if you're running as CLI app or daemon and does what it should: write to console or to syslog. — maverik, May 08 '13 at 16:58

score 4 · Answer 1 · edited May 08 '13 at 21:08

4

As suggested in the comments by maverik, I wrote a wrapper around syslog that determines whether to send the output to the log or console. Here it is in case anyone ever needs this.

void mylog (int level, const char *format, ...)
{
    va_list args;
    va_start (args, format);

    if (remote)
    {
        vsyslog(level, format, args);
    }   
    else
    {
        if (level == LOG_DEBUG)
            vsyslog(level, format, args);
        else
            vprintf(format, args);
    }
    va_end(args);
}

edited May 08 '13 at 21:08

Jens

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answered May 08 '13 at 17:35

Brandon Yates

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4

Call `va_end(args)` before returning from the function. – jxh May 08 '13 at 17:36

score 4 · Answer 2 · answered May 08 '13 at 17:42

4

As GNU-specific solution I would suggest using openlog(NULL, LOG_PERROR, your_facility). Not customizable(just duplicate on stderr).

answered May 08 '13 at 17:42

KAction

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Is there a way to redirect syslog messages to stdout?

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