Installing bcron on FreeBSD 7.0

bcron is a better cron (though the “b” in the name probably comes from the first name of its writer, Bruce Guenter).  It was created with security in mind, and is especially well suited for multi-user systems where the individual users need to be given access to their respective crontabs. With bcron this can be accomplished without compromising the system security.  Here’s a quote from the bcron page:

This is bcron, a new cron system designed with secure operations in mind. To do this, the system is divided into several seperate programs, each responsible for a seperate task, with strictly controlled communications between them. The user interface is a drop-in replacement for similar systems (such as vixie-cron), but the internals differ greatly.

As of writing of this bcron can not be found in the FreeBSD 7.0 ports system. Fortunately its installation is fairly straightforward.  Yet the included documentation is rather spartan so I provide a more complete outline below.

  1. Install latest bglibs if not yet installed** bglibs is best to install from a downloaded tarball rather than from the ports (while the ports version installs the libs in a more logical location at /usr/local/lib/bglibs/ the programs that utilize the library (bcron, ucspi-unix, etc.) have difficulty locating it.

    ** few symlinks are required (these refer to the locations bglibs installs itself when compiled from the tarball rather than from the ports):

    /usr/local/bglibs -> /usr/local/lib/bglibs
    /usr/local/bglibs/lib/ -> /usr/local/lib/
    /usr/local/bglibs/lib/ -> /usr/local/lib/

  2. Install ucspi-unix if not yet installed as bcron components communicate via UNIX sockets. This requires bglibs and also compiles and installs well using a downloaded tarball (it’s also available in ports at /usr/ports/sysutils/ucspi-unix, but I prefer to compile it from the downloaded tarball).
  3. Make sure /var has been moved off the root to /usr/var before proceeding. See an older post for details.
  4. Make sure daemontools (and hence supervise) has been installed and is operational as bcron will be started with it.
  5. Create a system user “cron” (for example by using vipw command) and group “cron” (by editing /etc/group). This user/group will own all the crontab files (though not /etc/crontab as it’s system crontab and needs to be owned by root:wheel).


    cron:*:50:50::0:0:BCron Sandbox:/nonexistent:/usr/sbin/nologin


  6. Create the spool & tmp directories:
    mkdir -p /var/spool/cron/crontabs /var/spool/cron/tmp
    mkfifo /var/spool/cron/trigger
    for i in crontabs tmp trigger; do
    chown cron:cron /var/spool/cron/$i
    chmod go-rwx /var/spool/cron/$i
  7. Create the configuration directory /usr/local/etc/bcron:mkdir -p /usr/local/etc/bcron** You can put any common configuration settings into this directory (it is an “ENVDIR”), like alternate spool directories in BCRON_SPOOL.
  8. Create the bcron service directories (there are three services) and add the scripts below it:

    mkdir -p /var/bcron/supervise/bcron-sched/log
    mkdir /var/bcron/supervise/bcron-spool
    mkdir /var/bcron/supervise/bcron-update

    Set their permissions to 1750 for security purposes (no world access, sticky bit):

    chmod 1750 /var/bcron/supervise/bcron-sched
    chmod 1750 /var/bcron/supervise/bcron-spool
    chmod 1750 /var/bcron/supervise/bcron-update

    Make all the run and log/run scripts executable by root, readable by group:

    chmod 740 /var/bcron/supervise/bcron-sched/run
    chmod 740 /var/bcron/supervise/bcron-sched/log/run
    chmod 740 /var/bcron/supervise/bcron-spool/run
    chmod 740 /var/bcron/supervise/bcron-update/run

    and make log bcron-sched subdir accessible by root, group:

    chmod 750 /var/bcron/supervise/bcron-sched/log


    exec 2>&1
    exec envdir /usr/local/etc/bcron bcron-start | multilog t /var/log/bcron


    exec >/dev/null 2>&1
    multilog t /var/log/bcron


    exec >/dev/null 2>&1
    envdir /usr/local/etc/bcron
    envuidgid cron
    sh -c ‘
    unixserver -U ${BCRON_SOCKET:-/var/run/bcron-spool}


    exec >/dev/null 2>&1
    bcron-update /etc/crontab

  9. Kill the deafult cron daemon and add the following to rc.conf so it won’t restart on reboot:

    #disable default cron; bcron is used instead (started by supervise)

  10. Symlink bcron services’ primary supervise directories to under /var/service to start bcron services (you can also use svc-add command if you have installed supervise-scripts):
    ln -s /var/bcron/supervise/bcron-sched /var/service/bcron-sched
    ln -s /var/bcron/supervise/bcron-spool /var/service/bcron-spool
    ln -s /var/bcron/supervise/bcron-update /var/service/bcron-update
  11. Set /etc/crontab permissions to 600, and make sure it’s owned by the root.
    chmod 600 /etc/crontab
    chown root:wheel /etc/crontab

    ** For other users the owner of the crontab file in their respective home folders would be cron:cron.

  12. Edit /etc/crontab and test that it gets updated. Note that there is a brief delay, perhaps one minute or so, after you save the crontab until the change becomes effective. Also note that the default shell for the crontab is /bin/sh. You might want to change it to something more powerful like c-shell (/bin/csh) or bash (/bin/bash) that you’re familiar with. You may also want to augment the default path, for example, by including /usr/local/bin for user-installed commands.

Installing daemontools service supervisor on FreeBSD 7.0

D. J. Bernstein’s daemontools includes a service supervisor which ensures services it supervises are restarted should they ever stop due to a program/system error. Daemontoos is easy to install, and is best installed from FreeBSD’s ports system at /usr/ports/sysutils/daemontools.  Be sure to also install the manual, which you can find in a sub-directory work/daemontools-man. The README file that can be found within instructs to [manually] install the manual entries using the command gzip *.8 ; cp *.8.gz /usr/share/man/man8/ (while residing in the daemontools-man directory). Once installed, there are few additional steps to do:

  1. Copy /usr/ports/sysutils/daemontools/work/ to
    /usr/local/etc/rc.d/ and give it owner execute privileges with
    chmod 700 /usr/local/etc/rc.d/
  2. Create /var/service and create a symlink to it from /service
    mkdir /var/service
    ln -s /var/service /service
  3. Add following to /etc/rc.conf:
    #start /var/service scanning
  4. Reboot the system (svscan will *not* start on a BSD system before the system is rebooted)

Optionally you can also install Bruce Guenter’s supervise-scripts that make life a whole lot easier with daemontools’ supervise.

  1. Install latest bglibs if not yet installed
    ** bglibs is best to install from a downloaded tarball rather than from the ports (while the ports version installs the libs in a more logical location at /usr/local/lib/bglibs/ the programs that utilize the library (bcron, ucspi-unix, etc.) have difficulty locating it.** few symlinks are required (these refer to the locations bglibs installs itself when compiled from the tarball rather than from the ports):
    /usr/local/bglibs -> /usr/local/lib/bglibs
    /usr/local/bglibs/lib/ -> /usr/local/lib/
    /usr/local/bglibs/lib/ -> /usr/local/lib/
  2. Download, compile, and install supervise-scripts. Once installed, you’ll find new commands svc-start, svc-stop, svc-restart, svc-add, svc-remove, svc-isdown, svc-isup, svc-waitdown, svc-waitup, and svc-status in /usr/local/bin. These make scripting and managing services much easier.

When switching programs to be svscan-started and svscan-managed, remember to make sure they’re not being started either as default services by the system, or that a prior startup setting doesn’t exist in  /etc/rc.conf. Disable them (depending on the service) by commenting out the startup in /etc/rc.conf, by adding a “NO” clause in /etc/rc.conf (such as cron_enable=”NO”), or by disabling the corresponding startup script in /usr/local/etc/rc.d.

If you mess up a service initialization, uninstall the failed service (i.e. unlink the service’s primary service directory from /var/service), delete the “supervise” subfolders (and “down” file if present) from the service’s primary service directory (there’s one also in the “log” subfolder). Then reboot the system, and reinstall the service either by using the supervise-scripts command svc-add, or by simply symlinking the service’s primary service directory to /var/service (for example ln -s /var/db/mysql-supervise /var/service/mysql).

Moving var, tmp Off the Root in FreeBSD

One one of the first things I do on a newly installed FreeBSD system is to move /var and /tmp to under /usr. Since I usually allocate about 4Gb for the root slice and the rest of a disk—usually several hundred gigabytes—goes to /usr (well, there’s also the swap slice that takes few gigabytes) having /var and /tmp there is more comfortable as some log files, database files, or some temp files can sometimes grow to multi-gigabyte size and exhaust the root space.

Below is a simple procedure to move the /var to /usr/var and /tmp to /usr/var/tmp. This is best to do early on in a new system installation since many services tend to hook into /tmp and/or /var, and may thus lock files in those directories making the move more difficult. If you’re making this move on an established system, at least stop all the services that might interfere with the process (such as database services). It might even be a good idea to boot into a single user mode (if you do so, remember to correctly mount your disks before proceeding). I usually do this early in a new system install, before installing any major services, or at least before scripting them to run.

  1. Move /var to /usr/var
    mkdir /usr/var
    cd /var
    tar cvf - . | (cd /usr/var; tar xvf - )
    cd /
    chflags -R noschg /var
    rm -rf /var
    ln -s /usr/var /var
  2. Move /tmp to /usr/var/tmp
    mkdir /usr/var/tmp
    cd /tmp
    tar cvf - . | (cd /usr/var/tmp; tar xvf - )
    cd /
    chflags -R noschg /tmp
    rm -rf /tmp
    ln -s /usr/var/tmp /tmp
    chmod -h 777 /tmp
    chmod 1777 /usr/var/tmp

FreeBSD 7.0-RELEASE Kernel Optimization

Below is my FreeBSD 7.0 kernel configuration file.  I created it on my reference system, to be used on four production servers whose hardware configurations differ some.  For that reason there’re few options (indicated as “[OPTION]”) that are conditional for the configurations. I’ve also left in IPv6 options which are currently commented out, but that I may take into use later if/when IPv6 becomes more prevalent in the environment these servers operate.

# INERTIA -- Inertia kernel configuration file for FreeBSD/i386
# For more information on this file, please read the handbook section on
# Kernel Configuration Files:
# The handbook is also available locally in /usr/share/doc/handbook
# if you've installed the doc distribution, otherwise always see the
# FreeBSD World Wide Web server ( for the
# latest information.
# An exhaustive list of options and more detailed explanations of the
# device lines is also present in the ../../conf/NOTES and NOTES files.
# If you are in doubt as to the purpose or necessity of a line, check first
# in NOTES.
# Based on
# $FreeBSD: src/sys/i386/conf/GENERIC,v 1.474. 2008/02/06 03:24:28 scottl Exp $

ident		INERTIA
machine		i386
cpu		I686_CPU

options		SMP 			# Symmetric MultiProcessor Kernel (`device apic' is also required for multiprocessor use)
options 	SCHED_4BSD		# 4BSD scheduler
options 	PREEMPTION		# Enable kernel thread preemption
options 	INET			# InterNETworking
#options 	INET6			# IPv6 communications protocols
options 	FFS			# Berkeley Fast Filesystem
options 	SOFTUPDATES		# Enable FFS soft updates support
options 	UFS_ACL			# Support for access control lists
options 	UFS_DIRHASH		# Improve performance on big dirs
options 	CD9660			# ISO 9660 Filesystem
options 	PROCFS			# Process filesystem (requires PSEUDOFS)
options 	PSEUDOFS		# Pseudo-filesystem framework
options		MSDOSFS			# MSDOS filesystem support (for floppies)
options 	COMPAT_43		# Compatible with BSD 4.3 (required)
options 	COMPAT_FREEBSD4		# Compatible with FreeBSD4
options 	COMPAT_FREEBSD5		# Compatible with FreeBSD5
options 	COMPAT_FREEBSD6		# Compatible with FreeBSD6
options 	SCSI_DELAY=15000	# Delay (in ms) before probing SCSI (TWA/TWE issue)
options 	KTRACE			# ktrace(1) support
options 	SYSVSHM			# SYSV-style shared memory
options 	SYSVMSG			# SYSV-style message queues
options 	SYSVSEM			# SYSV-style semaphores
options 	_KPOSIX_PRIORITY_SCHEDULING # POSIX P1003_1B real-time extensions
options 	KBD_INSTALL_CDEV	# install a CDEV entry in /dev, may be needed to hot-plug USB keyboards
options 	AHC_REG_PRETTY_PRINT	# Print register bitfields in debug output
options 	AHD_REG_PRETTY_PRINT	# Print register bitfields in debug output
options 	ADAPTIVE_GIANT		# Giant mutex is adaptive
options		ACCEPT_FILTER_HTTP	# Must be here or AcceptFilter won't work w/Apache2
options		SC_DISABLE_REBOOT	# Disable Ctrl-Alt-Del reboot (this is a server)

device		apic			# I/O APIC (required)
device		npx   			# The Numeric Processing eXtension driver (required)

device		pci
device		isa			# Required by npx

device		fdc			# Floppy drives

device		ata			# ATA and ATAPI devices
device		atadisk			# ATA disk drives
device		ataraid			# ATA RAID drives [OPTION]
device		atapicd			# ATAPI CDROM drives
options 	ATA_STATIC_ID		# Static device numbering

device		scbus			# SCSI bus (required for SCSI, ALSO REQ'D FOR SATA-RAID, USB/umass)
device		da			# Direct Access (disks)
device		pass			# Passthrough device (direct SCSI access)

#device		twe			# 3ware ATA RAID [OPTION]
#device		twa			# 3ware 9000 series PATA/SATA RAID [OPTION]
#options	TWA_DEBUG		# 0-10; 10 prints the most messages; enable for twa debug only

device		atkbdc			# AT keyboard controller
device		atkbd			# AT keyboard
device		kbdmux			# keyboard multiplexer

device		vga			# VGA video card driver
device		sc			# syscons, the default console driver
device		sio			# 8250, 16[45]50 based serial ports

device		ppc			# Parallel port
device		ppbus			# Parallel port bus (required)
device		lpt			# Printer
device		ppi			# Parallel port interface device

#device		miibus			# MII bus support (required by some NICs) [OPTION]
#device		fxp			# Intel EtherExpress PRO/100B (82557, 82558); requires miibus [OPTION]
device		em			# Intel PRO/1000 adapter Gigabit Ethernet Card [OPTION]

options		DEVICE_POLLING		# Imporoves network driver performance

device		coretemp		# On-die temperature sensor on Intel Core and newer CPUs [OPTION]

device		loop			# Network loopback
device		random			# Entropy device
device		ether			# Ethernet support
device		pty			# Pseudo-ttys (telnet etc)
#device		gif			# IPv6 and IPv4 tunneling
#device		faith			# IPv6-to-IPv4 relaying (translation)
device		bpf			# Berkeley packet filter

# USB support [OPTION]
device		uhci			# USB support / UHCI PCI->USB interface
device		ohci			# USB support / OHCI PCI->USB interface
device		ehci			# USB support / EHCI PCI->USB interface (USB 2.0)
device		usb			# USB support / USB Bus (required)
device		ugen			# USB support / Generic
device		uhid			# USB support / "Human Interface Devices"
device		ukbd			# USB support / Keyboard
device		umass			# USB support / Disks/Mass storage - Requires scbus and da

options		COMPAT_LINUX		# Linux compat / Enable Linux ABI emulation
options		COMPAT_AOUT		# Linux compat / Enable i386 a.out binary support
options		LINPROCFS		# Linux compat / Enable procfs support (COMPAT_LINUX / PSEUDOFS)