Date: Mon, 16 Oct 1995 22:54:04 +0100 From: Olof Johansson <offe@dawnrazor.campus.luth.se> To: "Justin T. Gibbs" <gibbs@freefall.FreeBSD.org> Cc: hackers@freebsd.org Subject: Re: wtmp efficiency Message-ID: <199510162154.WAA08655@dawnrazor.campus.luth.se> In-Reply-To: Your message of "Mon, 16 Oct 1995 14:14:34 MST." <199510162114.OAA19312@aslan.cdrom.com>
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I've found (and fixed) the problem.
It's the fact that ftp and uucp connections get 'ftp' or 'uucp' + pid as
tty_line in wtmp. The pid isn't removed when looking up the tty, so the list
gets bigger and bigger.
For 'ftp-only' wtmp files the time for parsing the file is proportional to
n^2, where n is the number of entries in the file...
(I have an exam on data structures and algorithms next week *grin*).
The following patch fixes the problem.
*** last.c Mon Aug 7 19:08:00 1995
--- lastold.c Mon Oct 16 22:43:48 1995
***************
*** 202,207 ****
--- 202,215 ----
continue;
}
/*
+ * Fix tty-line for ftp and uucp entries.
+ * (same as in want(), see there for more info)
+ */
+ if (!strncmp(bp->ut_line, "ftp", 3))
+ bp->ut_line[3] = '\0';
+ else if (!strncmp(bp->ut_line, "uucp", 3))
+ bp->ut_line[4] = '\0';
+ /*
* if the line is '{' or '|', date got set; see
* utmp(5) for more info.
*/
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