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authorDenis Vlasenko2009-03-11 14:40:00 +0000
committerDenis Vlasenko2009-03-11 14:40:00 +0000
commita19e64933c600b7f05232ad80bb5db85c115e42d (patch)
treebb832b3fc677066c155b19eaccea085298b1b718 /docs
parent4774179cb9e04030485773adf2b7b1055a10faeb (diff)
downloadbusybox-a19e64933c600b7f05232ad80bb5db85c115e42d.zip
busybox-a19e64933c600b7f05232ad80bb5db85c115e42d.tar.gz
docs/logging_and_backgrounding.txt: new mini-doc
dnsd: remove statics, remove nerly-useless SIGINT handler crond: correct more of logfile to 0666 (as usual, umask allows user to remove unwanted bits). nameif: print errors to stderr too, not just to syslog function old new delta udhcp_read_interface 308 306 -2 ttl 4 - -4 fileconf 4 - -4 dnsentry 4 - -4 interrupt 19 - -19 dnsd_main 1463 1394 -69 ------------------------------------------------------------------------------ (add/remove: 0/4 grow/shrink: 0/2 up/down: 0/-102) Total: -102 bytes text data bss dec hex filename 808161 476 7864 816501 c7575 busybox_old 807994 468 7856 816318 c74be busybox_unstripped
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+ Logging and backgrounding
+
+By default, bb_[p]error_msg[_and_die] messages go to stderr,
+and of course, usually applets do not auto-background. :)
+
+Historically, daemons and inetd services are different.
+
+Busybox is trying to provide compatible behavior, thus if an applet
+is emulating an existing utility, it should mimic it. If utility
+auto-backgrounds itself, busybox applet should do the same.
+If utility normally logs to syslog, busybox applet should do
+the same too.
+
+However, busybox should not needlessly restrict the freedom
+of the users. And users have different needs and different preferences.
+Some might like logging everything from daemons to syslog.
+Others prefer running stuff under runsv/svlogd and thus would like
+logging to stderr and no daemonization.
+
+To help with that, busybox applets should have options to override
+default behavior, whatever that is for a given applet.
+
+
+Current sutiation is a bit of a mess:
+
+acpid - auto-backgrounds unless -d
+crond - auto-backgrounds unless -f, logs to syslog unless -d or -L.
+ option -d logs to stderr, -L FILE logs to FILE
+devfsd - (obsolete)
+dnsd - option -d makes it auto-background and log to syslog
+fakeidentd - inetd service. Auto-backgrounds and logs to syslog
+ if no -f and no -i and no -w (-i is "inetd service" flag,
+ -w is "inetd-wait service" flag)
+ftpd - inetd service. Logs to syslog always, with -v logs to strerr too
+httpd - auto-backgrounds unless -f or -i
+ (-i is "inetd service" flag)
+inetd - auto-backgrounds unless -f, logs to syslog unless -e
+klogd - auto-backgrounds unless -n
+syslogd - auto-backgrounds unless -n
+telnetd - auto-backgrounds unless -f or -i
+ (-i is "inetd service" flag)
+udhcpc - auto-backgrounds unless -f after lease is obtained,
+ option -b makes it background sooner (when lease attempt
+ fails and retries start),
+ after backgrounding it stops logging to stderr;
+ logs to stderr, but option -S makes it log *also* to syslog
+udhcpd - auto-backgrounds and do not log to stderr unless -f,
+ otherwise logs to stderr, but option -S makes it log *also* to syslog
+zcip - auto-backgrounds and logs *also* to syslog unless -f
+
+miscutils/crond.c: logmode = LOGMODE_SYSLOG;
+networking/dnsd.c: logmode = LOGMODE_SYSLOG;
+networking/ftpd.c: logmode = LOGMODE_SYSLOG;
+networking/ftpd.c: logmode |= LOGMODE_SYSLOG;
+networking/inetd.c: logmode = LOGMODE_SYSLOG;
+networking/isrv_identd.c: logmode = LOGMODE_SYSLOG;
+networking/telnetd.c: logmode = LOGMODE_SYSLOG;
+networking/udhcp/dhcpc.c: logmode = LOGMODE_NONE;
+networking/udhcp/dhcpc.c: logmode |= LOGMODE_SYSLOG;
+networking/udhcp/dhcpc.c: logmode &= ~LOGMODE_STDIO;
+networking/udhcp/dhcpd.c: logmode = LOGMODE_NONE;
+networking/udhcp/dhcpd.c: logmode |= LOGMODE_SYSLOG;
+networking/zcip.c: logmode |= LOGMODE_SYSLOG;
+
+
+These daemons seem to never auto-background/log to syslog:
+
+lpd - inetd service. Has nothing to log so far, though
+dhcprelay - standard behavior
+inotifyd - standard behavior
+runsv - standard behavior
+runsvdir - standard behavior
+svlogd - standard behavior
+tcpsvd, udpsvd - standard behavior
+tftpd - standard behavior
+
+
+Non-daemons (seems to be use syslog for a good reason):
+
+networking/nameif.c: logmode |= LOGMODE_SYSLOG;
+loginutils/chpasswd.c: logmode = LOGMODE_BOTH;
+loginutils/chpasswd.c: logmode = LOGMODE_STDIO;
+loginutils/getty.c: logmode = LOGMODE_BOTH;
+loginutils/getty.c: logmode = LOGMODE_NONE;
+loginutils/passwd.c: logmode = LOGMODE_STDIO;
+loginutils/passwd.c: logmode = LOGMODE_BOTH;
+loginutils/sulogin.c: logmode = LOGMODE_SYSLOG; (used if stdio isn't a tty)
+loginutils/sulogin.c: logmode = LOGMODE_BOTH;
+util-linux/mount.c: logmode = LOGMODE_SYSLOG; (used in a backgrounded NFS mount helper)