Re: [PATCH] Verbose git-daemon logging

From: Junio C Hamano <junkio@cox.net>
Date: Sep 22, 2005, 23:42 UTC
Message-ID: <7vd5n0lle8.fsf@assigned-by-dhcp.cox.net>
In-Reply-To: <20050922092528.GB21019@pasky.or.cz>

Petr Baudis <pasky@suse.cz> writes:

> What would be knowing parent PID be useful for? (It's not really the PID
> number that's useful anyway (at least mostly), it's just a good unique
> identifier to distinguish between several simultaneous sessions.)

Maybe running two daemons serving two sets of repos? But anyway what you have look more consistent so let's keep that.

> Fixed up patch follows.

Thanks.

Show 23 quoted lines

> +static void logreport(const char *err, va_list params)
> +{
> +	/* We should do a single write so that it is atomic and output
> +	 * of several processes does not get intermangled. */
> +	char buf[1024];
> +	int buflen;
> +	int maxlen, msglen;
> +
> +	buflen = snprintf(buf, sizeof(buf), "[%d] ", getpid());
> +
> +	maxlen = sizeof(buf) - buflen - 1;
> +	msglen = vsnprintf(buf + buflen, maxlen, err, params);
> +	if (msglen > maxlen)
> +		msglen = maxlen;
> +	else if (msglen < 0)
> +		msglen = -1; /* Protect against weird return values. */
> +	buflen += msglen;
> +
> +	buf[buflen++] = '\n';
> +	buf[buflen] = '\0';
> +
> +	fputs(buf, stderr);
> +}

The tail part still looks odd here.  Maybe something like this?

+static void logreport(const char *err, va_list params) +{ + /* We should do a single write so that it is atomic and output + * of several processes does not get intermangled. */ + char buf[1024]; + int buflen; + int maxlen, msglen; + + /* sizeof(buf) should be big enough for "[pid] \n" */ + buflen = snprintf(buf, sizeof(buf), "[%d] ", getpid()); + + maxlen = sizeof(buf) - buflen - 1; /* -1 for our own LF */ + msglen = vsnprintf(buf + buflen, maxlen, err, params); + + /* maxlen counted our own LF but also counts space given to + * vsnprintf for the terminating NUL. We want to make sure that + * we have space for our own LF and NUL after the "meat" of the + * message, so truncate it at maxlen - 1. + */ + if (msglen > maxlen - 1) + msglen = maxlen - 1; + else if (msglen < 0) + msglen = 0; /* Protect against weird return values. */ + buflen += msglen; + + buf[buflen++] = '\n'; + buf[buflen] = '\0'; + + fputs(buf, stderr); +}