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syslogd: allow the reporting of buffer overflows to be disabled.

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This generally isn't a good thing, nothing should be discard silently.
However, for systems that don't want big syslogd buffers or are too slow
to log effectively this reporting can now be disabled.
This commit is contained in:
roy 2018-11-04 20:45:21 +00:00
parent 0402a70e1e
commit 9adaa956c5
2 changed files with 26 additions and 9 deletions
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9
usr.sbin/syslogd/syslogd.8
View File

@ -1,4 +1,4 @@
.\" $NetBSD: syslogd.8,v 1.56 2018/11/04 20:23:08 roy Exp $
.\" $NetBSD: syslogd.8,v 1.57 2018/11/04 20:45:21 roy Exp $
.\"
.\" Copyright (c) 1983, 1986, 1991, 1993
.\" The Regents of the University of California. All rights reserved.
@ -37,7 +37,7 @@
.Nd log systems messages
.Sh SYNOPSIS
.Nm
.Op Fl dnrSsTUv
.Op Fl dnrSsTUvX
.Op Fl b Ar bind_address
.Op Fl B Ar buffer_length
.Op Fl f Ar config_file
@ -65,6 +65,9 @@ which corresponds to it is used.
Sets the receiving buffer length.
The default is 16384 bytes.
If syslogd reports buffer overflow, this needs increasing.
If you don't care about it being reported, see the
.Fl X
option.
.It Fl d
Enable debugging to the standard output,
and do not disassociate from the controlling terminal.
@ -154,6 +157,8 @@ If specified once, the numeric facility and priority are logged with
each locally-written message.
If specified more than once, the names of the facility and priority are
logged with each locally-written message.
.It Fl X
Disable logging of buffer overflow.
.El
.Pp
.Nm

26
usr.sbin/syslogd/syslogd.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: syslogd.c,v 1.126 2018/11/04 20:23:08 roy Exp $ */
/* $NetBSD: syslogd.c,v 1.127 2018/11/04 20:45:21 roy Exp $ */
/*
* Copyright (c) 1983, 1988, 1993, 1994
@ -39,7 +39,7 @@ __COPYRIGHT("@(#) Copyright (c) 1983, 1988, 1993, 1994\
#if 0
static char sccsid[] = "@(#)syslogd.c 8.3 (Berkeley) 4/4/94";
#else
__RCSID("$NetBSD: syslogd.c,v 1.126 2018/11/04 20:23:08 roy Exp $");
__RCSID("$NetBSD: syslogd.c,v 1.127 2018/11/04 20:45:21 roy Exp $");
#endif
#endif /* not lint */
@ -193,6 +193,7 @@ int SyncKernel = 0; /* write kernel messages synchronously */
int UniquePriority = 0; /* only log specified priority */
int LogFacPri = 0; /* put facility and priority in log messages: */
/* 0=no, 1=numeric, 2=names */
int LogOverflow = 1; /* 0=no, any other value = yes */
bool BSDOutputFormat = true; /* if true emit traditional BSD Syslog lines,
* otherwise new syslog-protocol lines
*
@ -316,7 +317,7 @@ main(int argc, char *argv[])
/* should we set LC_TIME="C" to ensure correct timestamps&parsing? */
(void)setlocale(LC_ALL, "");
while ((ch = getopt(argc, argv, "b:B:dnsSf:m:o:p:P:ru:g:t:TUv")) != -1)
while ((ch = getopt(argc, argv, "b:B:dnsSf:m:o:p:P:ru:g:t:TUvX")) != -1)
switch(ch) {
case 'b':
bindhostname = optarg;
@ -395,6 +396,9 @@ main(int argc, char *argv[])
if (LogFacPri < 2)
LogFacPri++;
break;
case 'X':
LogOverflow = 0;
break;
default:
usage();
}
@ -663,7 +667,7 @@ usage(void)
{
(void)fprintf(stderr,
"usage: %s [-dnrSsTUv] [-b bind_address] [-B buffer_length]\n"
"usage: %s [-dnrSsTUvX] [-b bind_address] [-B buffer_length]\n"
"\t[-f config_file] [-g group]\n"
"\t[-m mark_interval] [-P file_list] [-p log_socket\n"
"\t[-p log_socket2 ...]] [-t chroot_dir] [-u user]\n",
@ -712,7 +716,10 @@ dispatch_read_klog(int fd, short event, void *ev)
if (rv > 0) {
klog_linebuf[klog_linebufoff + rv] = '\0';
printsys(klog_linebuf);
} else if (rv < 0 && errno != EINTR) {
} else if (rv < 0 &&
errno != EINTR &&
(errno != ENOBUFS || LogOverflow))
{
/*
* /dev/klog has croaked. Disable the event
* so it won't bother us again.
@ -756,7 +763,10 @@ dispatch_read_funix(int fd, short event, void *ev)
if (rv > 0) {
linebuf[rv] = '\0';
printline(LocalFQDN, linebuf, 0);
} else if (rv < 0 && errno != EINTR) {
} else if (rv < 0 &&
errno != EINTR &&
(errno != ENOBUFS || LogOverflow))
{
logerror("recvfrom() unix `%.*s'",
(int)SUN_PATHLEN(&myname), myname.sun_path);
}
@ -791,7 +801,9 @@ dispatch_read_finet(int fd, short event, void *ev)
len = sizeof(frominet);
rv = recvfrom(fd, linebuf, linebufsize-1, 0,
(struct sockaddr *)&frominet, &len);
if (rv == 0 || (rv < 0 && errno == EINTR))
if (rv == 0 ||
(rv < 0 && (errno == EINTR ||
(errno == ENOBUFS && LogOverflow == 0))))
return;
else if (rv < 0) {
logerror("recvfrom inet");