/usr/sbin/syslogd [-d] [-f configfile] [-m markinterval] [-p path] [-t | -T]
A system message consists of a single line of text, which may be prefixed with a priority code number enclosed in angle-brackets (<>); priorities are defined in <sys/syslog.h>.
syslogd reads from the STREAMS log driver, /dev/log, and from any transport provider specified in /etc/netconfig, /etc/net/transport/hosts, and /etc/net/transport/services.
syslogd reads the configuration file when it starts up, and again whenever it receives a HUP signal (see signal.h(3HEAD), at which time it also closes all files it has open, re-reads its configuration file, and then opens only the log files that are listed in that file. syslogd exits when it receives a TERM signal.
As it starts up, syslogd creates the file /var/run/syslog.pid, if possible, containing its process identifier (PID).
If message ID generation is enabled (see log(7D)), each message will be preceded by an identifier in the following format: [ID msgid facility.priority]. msgid is the message's numeric identifier described in msgid(1M). facility and priority are described in syslog.conf(4). [ID 123456 kern.notice] is an example of an identifier when message ID generation is enabled.
If the message originated in a loadable kernel module or driver, the kernel module's name (for example, ufs) will be displayed instead of unix. See EXAMPLES for sample output from syslogd with and without message ID generation enabled.
In an effort to reduce visual clutter, message IDs are not displayed when writing to the console; message IDs are only written to the log file. See EXAMPLES.
The /etc/default/syslogd file contains the following default parameter settings, which are in effect if neither the -t nor -T option is selected. See FILES.
The recommended way to allow or disallow message logging is through the use of the service management facility (smf(5)) property:
This property specifies whether remote messages are logged. log_from_remote=true is equivalent to the -t command-line option and false is equivalent to the -T command-line option. The default value for -log_from_remote is false. See NOTES, below.
The following example shows the output from syslogd when message ID generation is not enabled:
Sep 29 21:41:18 cathy unix: alloc /: file system full
Example 2 syslogd Output with ID generation Enabled
The following example shows the output from syslogd when message ID generation is enabled. The message ID is displayed when writing to log file /var/adm/messages.
Sep 29 21:41:18 cathy ufs: [ID 845546 kern.notice] alloc /: file system full
Example 3 syslogd Output with ID Generation Enabled
The following example shows the output from syslogd when message ID generation is enabled when writing to the console. Even though message ID is enabled, the message ID is not displayed at the console.
Sep 29 21:41:18 cathy ufs: alloc /: file system full
Example 4 Enabling Acceptance of UDP Messages from Remote Systems
The following commands enable syslogd to accept entries from remote systems.
# svccfg -s svc:/system/system-log setprop config/log_from_remote = true # svcadm restart svc:/system/system-log
When syslogd receives a HUP signal, it attempts to complete outputting pending messages, and close all log files to which it is currently logging messages. If, for some reason, one (or more) of these files does not close within a generous grace period, syslogd discards the pending messages, forcibly closes these files, and starts reconfiguration. If this shutdown procedure is disturbed by an unexpected error and syslogd cannot complete reconfiguration, syslogd sends a mail message to the superuser on the current system stating that it has shut down, and exits.
Care should be taken to ensure that each window displaying messages forwarded by syslogd (especially console windows) is run in the system default locale (which is syslogd's locale). If this advice is not followed, it is possible for a syslog message to alter the terminal settings for that window, possibly even allowing remote execution of arbitrary commands from that window.
The syslogd service is managed by the service management facility, smf(5), under the service identifier:
When syslogd is started by means of svcadm(1M), if a value is specified for LOG_FROM_REMOTE in the /etc/defaults/syslogd file, the SMF property svc:/system/system-log/config/log_from_remote is set to correspond to the LOG_FROM_REMOTE value and the /etc/default/syslogd file is modified to replace the LOG_FROM_REMOTE specification with the following comment:
# LOG_FROM_REMOTE is now set using svccfg(1m), see syslogd(1m).
If neither LOG_FROM_REMOTE nor svc:/system/system-log/config/log_from_remote are defined, the default is to log remote messages.
On installation, the initial value of svc:/system/system-log/config/log_from_remote is false.
|June 20, 2021||OmniOS|