1 Logging and backgrounding 2 3By default, bb_[p]error_msg[_and_die] messages go to stderr, 4and of course, usually applets do not auto-background. :) 5 6Historically, daemons and inetd services are different. 7 8Busybox is trying to provide compatible behavior, thus if an applet 9is emulating an existing utility, it should mimic it. If utility 10auto-backgrounds itself, busybox applet should do the same. 11If utility normally logs to syslog, busybox applet should do 12the same too. 13 14However, busybox should not needlessly restrict the freedom 15of the users. And users have different needs and different preferences. 16Some might like logging everything from daemons to syslog. 17Others prefer running stuff under runsv/svlogd and thus would like 18logging to stderr and no daemonization. 19 20To help with that, busybox applets should have options to override 21default behavior, whatever that is for a given applet. 22 23 24Current situation is a bit of a mess: 25 26acpid - auto-backgrounds unless -d 27crond - auto-backgrounds unless -f, logs to syslog unless -d or -L. 28 option -d logs to stderr, -L FILE logs to FILE 29devfsd - (obsolete) 30dnsd - option -d makes it background and log to syslog 31fakeidentd - inetd service. Auto-backgrounds and logs to syslog 32 if no -f and no -i and no -w (-i is "inetd service" flag, 33 -w is "inetd-wait service" flag) 34ftpd - inetd service. Logs to syslog with -S, with -v logs to strerr too 35httpd - auto-backgrounds unless -f or -i (-i is "inetd service" flag) 36inetd - auto-backgrounds unless -f, logs to syslog unless -e 37klogd - auto-backgrounds unless -n 38syslogd - auto-backgrounds unless -n 39telnetd - auto-backgrounds unless -f or -i (-i is "inetd service" flag) 40udhcpc - auto-backgrounds unless -f after lease is obtained, 41 option -b makes it background sooner (when lease attempt 42 fails and retries start), 43 after backgrounding it stops logging to stderr; 44 logs to stderr, but option -S makes it log *also* to syslog 45udhcpd - auto-backgrounds and do not log to stderr unless -f, 46 otherwise logs to stderr, but option -S makes it log *also* to syslog 47zcip - auto-backgrounds and logs *also* to syslog unless -f 48 behaviour can be overridden with experimental LOGGING env.var 49 (can be set to either "none" or "syslog") 50 51Total: 13 applets (+1 obsolete), 52 4 log to syslog by default (crond fakeidentd inetd zcip), 53 5 never log to syslog (acpid httpd telnetd klogd syslogd, last two 54 - for obviously correct reasons), 55 there are no daemons which always log to syslog, 56 12 auto-background if not run as inetd services (all except dnsd. 57 Note that there is no "standard" dnsd AFAIKS). But see below 58 for daemons (tcpsvd etc) which don't auto-background. 59 60miscutils/crond.c: logmode = LOGMODE_SYSLOG; 61networking/dnsd.c: logmode = LOGMODE_SYSLOG; 62networking/ftpd.c: logmode = LOGMODE_NONE; 63networking/ftpd.c: logmode |= LOGMODE_SYSLOG; 64networking/inetd.c: logmode = LOGMODE_SYSLOG; 65networking/isrv_identd.c: logmode = LOGMODE_SYSLOG; 66networking/telnetd.c: logmode = LOGMODE_SYSLOG; 67networking/udhcp/dhcpc.c: logmode = LOGMODE_NONE; 68networking/udhcp/dhcpc.c: logmode |= LOGMODE_SYSLOG; 69networking/udhcp/dhcpc.c: logmode &= ~LOGMODE_STDIO; 70networking/udhcp/dhcpd.c: logmode = LOGMODE_NONE; 71networking/udhcp/dhcpd.c: logmode |= LOGMODE_SYSLOG; 72networking/zcip.c: logmode |= LOGMODE_SYSLOG; 73 74 75These daemons never auto-background and never log to syslog: 76 77lpd - inetd service. Has nothing to log so far, though 78dhcprelay - standard behavior 79inotifyd - standard behavior 80runsv - standard behavior 81runsvdir - standard behavior 82svlogd - standard behavior 83tcpsvd, udpsvd - standard behavior 84tftpd - standard behavior 85 86 87Non-daemons (seems to be use syslog for a good reason): 88 89networking/nameif.c: logmode |= LOGMODE_SYSLOG; 90loginutils/chpasswd.c: logmode = LOGMODE_BOTH; 91loginutils/chpasswd.c: logmode = LOGMODE_STDIO; 92loginutils/getty.c: logmode = LOGMODE_BOTH; 93loginutils/getty.c: logmode = LOGMODE_NONE; 94loginutils/passwd.c: logmode = LOGMODE_STDIO; 95loginutils/passwd.c: logmode = LOGMODE_BOTH; 96loginutils/sulogin.c: logmode = LOGMODE_SYSLOG; (used if stdio isn't a tty) 97loginutils/sulogin.c: logmode = LOGMODE_BOTH; 98util-linux/mount.c: logmode = LOGMODE_SYSLOG; (used in a backgrounded NFS mount helper) 99