update TODO

[elogind.git] / TODO

Bugfixes:
* check systemd-tmpfiles for selinux context hookup for mknod(), symlink() and similar

* swap units that are activated by one name but shown in the kernel under another are semi-broken

* Dangling symlinks of .automount unit files in .wants/ directories, set up
  automount points even when the original .automount file did not exist
  anymore. Only the .mount unit was still around.

* make polkit checks async

* properly handle .mount unit state tracking when two mount points are stacked one on top of another on the exact same mount point.

* add 'set -e' to scripts in test/
* make test in test/ work with separate output dir

* suppress log output on shutdown when "quiet" is used

Fedora 19:

* make anaconda write timeout=0 for encrypted devices

* external: maybe it is time to patch procps so that "ps" links to
  libsystemd-logind to print a pretty service name, seat name, session
  name in its output. Currently it only shows cgroup membership, but
  that's sometimes kinda hard to parse for a human.

* cgroup attrs:
  - update dbus interface docs in wiki

* journal is not closed properly at shutdown when run in a container?

* localed:
  - localectl: add listing support for X11 keymaps, by parsing /usr/share/X11/xkb/rules/xorg.lst
  - localectl: support new converted x11→console keymaps

* logind: Class property should probably know "background" or so as value for cron jobs, and the inhibition checks should filter those out too.

* timer logic is confused by units which are skipped due to failing condition
  http://lists.freedesktop.org/archives/systemd-devel/2013-February/008816.html

* timer logic is also confused if a service it triggers hasn't finished when the next timer elapses:
  http://lists.freedesktop.org/archives/systemd-devel/2013-February/009021.html

Features:

* matching against units is currently broken in journalctl. We really
  need another AND level in the expressions,
  i.e. sd_journal_add_conjunction().

* add ConditionArchitecture= or so

* teach ConditionKernelCommandLine= globs or regexes (in order to match foobar={no,0,off})

* hostnamectl: when a passed pretty hostname also qualifies as low-level name, then only set low-level name, and unset the pretty hostname

* we should log capabilities too

* Support SO_REUSEPORT with socket activation:
  - Let systemd maintain a pool of servers.
  - Use for seamless upgrades, by running the new server before stopping the
    old.

* after all byte-wise realloc() is slow, even on glibc, so i guess we
  need manual exponential loops after all

* BootLoaderSpec: drop allowing ext234 for $BOOT. Clarify that the
  kernel has to be in $BOOT. Clarify that the boot loader should be
  installed to the ESP. Define a way how an installer can figure out
  whether a BLS compliant boot loader is installed.

* man: remove .include documentation, and instead push people to use .d/*.conf

* disallow .include from included files

* safe_atod() is too naive, as it is vulnerable to locale parameters, should be locale independent.

* think about requeuing jobs when daemon-reload is issued? usecase:
  the initrd issues a reload after fstab from the host is accessible
  and we might want to requeue the mounts local-fs acquired through
  that automatically.

* neither pkexec nor sudo initialize environ[] from the PAM environment?

* rework specifier logic so that we can distuingish OOM errors from other errors

* systemd-inhibit: refuse taking delay locks

* journal-or-kmsg is currently broken? See reverted commit 4a01181e460686d8b4a543b1dfa7f77c9e3c5ab8.

* remove any syslog support from log.c -- we probably can't do this before split-off udev is gone for good

* fedora: connect the timer units of a service to the service via Also= in [Install], and maybe introduce timers.target

* fedora: F20: go timer units all the way, leave cron.daily for cron

* add a tool that lists active timer units plus their next elapstion and the time the units ran last

* man: document the very specific env the shutdown drop-in tools live in

* shutdown logging: store to EFI var, and store to USB stick?

* man: extend runlevel(8) to mention that runlevels suck, and are dead. Maybe  add runlevel(7) with a note about that too

* systemctl: maybe add "systemctl add-wants" or so...

* man: add a link to socket activation blog from systemd.socket(5)

* systemctl status: show drop-in snippets for service files in addition to service file path themesevles.

* man: add more examples to man pages

* man: maybe sort directives in man pages, and take sections from --help and apply them to man too

* add "# export SYSTEMD_PAGER=" to bash login

* /usr/bin/service should actually show the new command line

* fedora: suggest auto-restart on failure, but not on sucess and not on coredump. also, ask people to think about changing the start limit logic. Also point people to RestartPreventExitStatus=, SuccessExitStatus=

* write UI tool that pops up emergency messages from the journal as notification

* think about window-manager-run-as-user-service problem: exit 0 → activate shutdown.target; exit != 0 → restart service

* msgcatalog determine default language of entries from the catalog
  file name. i.e. foobar.de_DE.catalog would set the default entry
  name for the entries to de_DE if they aren't explicitly suffixed
  individually.

* figure out what we do about hostnames/fqdn in hostnamectl/hostnamed

* use "log level" rather than "log priority" everywhere

* ensure sd_journal_seek_monotonic actually works properly.

* timedate: have global on/off switches for auto-time (NTP), and auto-timezone that connman can subscribe to.

* support --root= in msgcatalog compiler

* Honour "-" prefix for InaccessibleDirectories= and ReadOnlyDirectories= to
  suppress errors of the specified path doesn't exist

* dev-setup.c: when running in a container, create a tiny stub udev
  database with the systemd tag set for all network interfaces found,
  so that libudev reports them as present, and systemd's .device units
  will be activated.

* merge unit_kill_common() and unit_kill_context()

* introduce ExecCondition= in services

* EFI:
  - fsck hookup for the ESP mount is missing
  - write man page for efi boot generator
  - honor language efi variables for default language selection (if there are any?)
  - honor timezone efi variables for default timezone selection (if there are any?)
  - introduce bootctl (backed by systemd-bootd) to control temporary and persistent default boot goal plus efi variables

* maybe do not install getty@tty1.service symlink in /etc but in /usr?

* re-enable "make check" for gtk-doc (broken for unknown reason)

* fstab: add new mount option x-systemd-after=/foobar/waldo to allow manual dependencies to other mount points
  https://bugzilla.redhat.com/show_bug.cgi?id=812826

* print a nicer explanation if people use variable/specifier expansion in ExecStart= for the first word

* mount: turn dependency information from /proc/self/mountinfo into dependency information between systemd units.

* logind:
  - logind: optionally, ignore idle-hint logic for autosuspend, block suspend as long as a session is around
  - When we update the kernel all kind of hibernation should be prohibited until shutdown/reboot
  - logind: wakelock/opportunistic suspend support
  - Add pretty name for seats in logind
  - logind: allow showing logout dialog from system?
  - logind: spawn user@..service on login
  - logind: non-local X11 server handling
  - logind: add equivalent to sd_pid_get_owner_uid() to the D-Bus API
  - pam: when leaving a session explicitly exclude the ReleaseSession() caller process from the killing spree
  - logind: GetSessionByPID() should accept 0 as PID value

* exec: when deinitializating a tty device fix the perms and group, too, not only when initializing. Set access mode/gid to 0620/tty.

* DeviceAllow/DeviceDeny: disallow everything by default, but whitelist /dev/zero, /dev/null and friends

* service: watchdog logic: for testing purposes allow ping, but do not require pong

* journal:
  - import and delete pstore filesystem content at startup
  - journald: also get thread ID from client, plus thread name
  - journal: when waiting for journal additions in the client always sleep at least 1s or so, in order to minimize wakeups
  - add API to close/reopen/get fd for journal client fd in libsystemd-journal.
  - fallback to /dev/log based logging in libsystemd-journal, if we can't log natively?
  - declare the local journal protocol stable in the wiki interface chart
  - journal: reuse XZ context
  - sd-journal: speed up sd_journal_get_data() with transparent hash table in bg
  - journald: when dropping msgs due to ratelimit make sure to write
    "dropped %u messages" not only when we are about to print the next
    message that works, but alraedy after a short tiemout
  - check if we can make journalctl by default use --follow mode inside of less if called without args?
  - maybe add API to send pairs of iovecs via sd_journal_send
  - journal: when writing journal auto-rotate if time jumps backwards
  - gatewayd: should run under its own UID
  - journal: add a setgid "systemd-journal" utility to invoke from libsystemd-journal, which passes fds via STDOUT and does PK access
  - journactl: support negative filtering, i.e. FOOBAR!="waldo",
    and !FOOBAR for events without FOOBAR.
  - journal: when rotating, copy over old acls/access mode
  - journal: send out marker messages every now and then, and immediately sync with fdatasync() afterwards, in order to have hourly guaranteed syncs.
  - journal: when we haven't written anything in a while, sync to disk and mark file as offline, in order to be more often than not in a clean state
  - journal-send.c, log.c: when the log socket is clogged, and we drop, count this and write a message about this when it gets unclogged again.
  - journal: find a way to allow dropping history early, based on priority, other rules
  - journal: When used on NFS, check payload hashes
  - journal: When used on NFS make sure wake up sd_journal_wait() every 2s, to handle missing inotify
  - Introduce journalctl -b <nr> to show journal messages of a previous boot
  - journald: check whether it is OK if the client can still modify delivered journal entries
  - journal live copy, based on libneon (client) and libmicrohttpd (server)
  - journald: add kernel cmdline option to disable ratelimiting for debug purposes
  - refuse taking lower-case variable names in sd_journal_send() and friends.
  - journald: we currently rotate only after MaxUse+MaxFilesize has been reached.
  - journal: deal nicely with byte-by-byte copied files, especially regards header
  - journalctl: show multiline log messages sanely, expand tabs, and show all valid utf8 messages
  - journal: store euid in journal if it differs from uid
  - journal: sanely deal with entries which are larger than the individual file size, but where the components would fit
  - journalctl: make journalctl smarter, and actually check groups that have access to /var/log/journal before printing message about recomming group membership for journal access

* document:
  - document unit_name_mangle()
  - document that deps in [Unit] sections ignore Alias= fileds in
    [Install] units of other units, unless those units are disabled
  - man: clarify that time-sync.target is not only sysv compat but also useful otherwise. Same for similar targets
  - Document word splitting syntax for ExecStart= and friends
  - document that units from /etc override those from /usr and /run
  - document the exit codes when services fail before they are exec()ed
  - document that service reload may be implemented as service reexec
  - document in wiki how to map ical recurrence events to systemd timer unit calendar specifications

* systemctl:
  - systemctl list-jobs - show dependencies
  - add systemctl switch to dump transaction without executing it
  - Add a verbose mode to "systemctl start" and friends that explains what is being done or not done
  - "systemctl disable" on a static unit prints no message and does
    nothing. "systemctl enable" does nothing, and gives a bad message
    about it. Should fix both to print nice actionable messages.
  - print nice message from systemctl --failed if there are no entries shown, and hook that into ExecStartPre of rescue.service/emergency.service
  - add new command to systemctl: "systemctl system-reexec" which reexecs as many daemons as virtually possible
  - systemctl enable: improve the success messages (i.e. more human readable, less shell-like)
  - systemctl enable: fail if target to alias into doesn't exist? maybe show how many units are enabled afterwards?
  - systemctl: "Journal has been rotated since unit was started." message is misleading
  - support "systemctl stop foobar@.service" to stop all units matching a certain template
  - Something is wrong with symlink handling of "autovt@.service" in "systemctl list-unit-files"
  - add configuration/switches to use
    freeze (http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git) and
    standby (https://bugs.freedesktop.org/show_bug.cgi?id=57793) as suspend modes

* introduce ntp.service (or suchlike) as symlink that is used to arbitrate between various NTP implementations

* deal with sendmail/postfix exclusivity

* timer units:
  - configurable jitter for timer events
  - timer events with system resume
  - timer units should get the ability to trigger when:
    o CLOCK_REALTIME makes jumps (TFD_TIMER_CANCEL_ON_SET)
    o DST changes
  - Support 2012-02~4 as syntax for specifying the fourth to last day of the month.

* update the kernel's TZ (sys_tz) when DST changes

* sync down the system time to the RTC when:
    - CLOCK_REALTIME makes jumps (the user explicitely requested a time set)
    - DST/timezone changes && ntp is active && RTC-in-localtime (never do it without ntp)
  This takes care of syncing ntpdate updates to the RTC, and DST updates for localtime
  mode, it will never touch the RTC if the no reliable time source is active or the
  user did not request anything like it.

* hwdb:
  - implement conditional properties (dmi matches)
  - hwdb --filter=ID_DRIVE_*

* if booted in "quiet" mode, and an error happens, turn on status
  output again, so that the emergency mode isn't totally
  surprising. Also, terminate plymouth.

* libunwind support for coredump pattern hook, and includes this in
  the message for coredumps. After all, libunwind is now capable to
  unwind coredumps since a few weeks ago. This probably requires that
  we have nice support for multi-line messages on display in
  logs-show.c. Alternatively: use libelfutil, which seems to be the
  better supported alternative.

* figure out relation of --all and --full in the various tools

* add libsystemd-password or so to query passwords during boot using the password agent logic

* If we show an error about a unit (such as not showing up) and it has no Description string, then show a description string generated form the reverse of unit_name_mangle().

* fedup: add --unit to systemctl switch-root somehow
* fedup: don't delete initrd on switch-root
* fedup: generator

* timedated:
  - timedated: refuse time changes when NTP is on

* clean up date formatting and parsing so that all absolute/relative timestamps we format can also be parsed

* introduce generic AUGMENT_PID=, AUGMENT_DEVICE= fields

* on shutdown: move utmp, wall, audit logic all into PID 1 (or logind?), get rid of systemd-update-utmp-runlevel

* add "provisioning" instructions to setup an empty /etc + /var
    - used to setup a new container from a shared /usr
    - superset of tmpfiles model
    - instructions shipped by packages and stored in /usr/lib/
    - compose /etc/passwd and /etc/group, copy files
    - able to create uid + gid used by packages, for file ownership

* make repeated alt-ctrl-del presses printing a dump, or even force a reboot without
  waiting for the timeout

* high level net_prio setting in execution context

* hostnamed: before returning information from /etc/machine-info.conf check the modification data and reread. Similar for localed, ...

* currently x-systemd.timeout is lost in the initrd, since crypttab is copied into dracut, but fstab isn't

* WorkingDirectory: support env var replacements like in ExecStart= so that people can use $HOME

* refuse boot if /etc/machine-id is not useful (or set taint?)

* nspawn:
  - nspawn: consider changing users for -u with su, so that NSS resolving works correctly
  - nspawn: implement personality changes a la linux32(8)
  - nspawn: --read-only is not applied recursively to submounts
  - nspawn: make use of device cgroup controller by default
  - bind mount read-only the cgroup tree higher than nspawn
  - nspawn: investigate whether we can support the same as LXC's
    lxc.network.type=phys mode, and pass through entire network
    interfaces to the container
  - nspawn: maybe add a way to drop additional caps, in addition to add additional caps
  - nspawn: maybe explicitly reset loginuid?
  - nspawn: move all containers to name=systemd:/containers/, and introduce externally visible names for containers
  - nspawn: make it work for dwalsh and shared /usr containers -- tmpfs mounts as command line parameters, selinux exec context

* cryptsetup:
  - cryptsetup-generator: warn if the password files are world-readable
  - cryptsetup-generator: add RequiresMountsFor= to cryptseup service files referencing a file, similar for devices
  - cryptsetup-generator: allow specification of passwords in crypttab itself
  - move cryptsetup key caching into kernel keyctl?
    https://bugs.freedesktop.org/show_bug.cgi?id=54982
  - when key file cannot be found, read it from kbd in cryptsetup

* move debug shell to tty6 and make sure this doesn't break the gettys on tty6

* hw watchdog: optionally try to use the preset watchdog timeout instead of always overriding it
  https://bugs.freedesktop.org/show_bug.cgi?id=54712

* after deserializing sockets in socket.c we should reapply sockopts and things

* make timer units go away after they elapsed

* http://lists.freedesktop.org/archives/systemd-devel/2012-September/006502.html
  (network and remote-fs on shutdown)

* come up with a nice way to write queue/read_ahead_kb for a block device without interfering with readahead

* move PID 1 segfaults to /var/lib/systemd/coredump?

* create /sbin/init symlinks from the build system

* Query Paul Moore about relabelling socket fds while they are open

* system.conf should have controls for cgroups

* allow writing multiple conditions in unit files on one line

* explore multiple service instances per listening socket idea

* shutdown: don't read-only mount anything when running in container

* MountFlags=shared acts as MountFlags=slave right now.

* ReadOnlyDirectories= is not applied recursively to submounts

* drop PID 1 reloading, only do reexecing (difficult: Reload()
  currently is properly synchronous, Reexec() is weird, because we
  can't delay the response properly until we are back, so instead of
  being properly synchronous we just keep open the fd and close it
  when done. That means clients don't get a successful method reply,
  but much rather a disconnect on success.

* remember which condition failed for services, not just the fact that something failed

* use opterr = 0 for all getopt tools

* properly handle loop back mounts via fstab, especially regards to fsck/passno

* allow services with no ExecStart= but with an ExecStop=

* dracut-shutdown needs to be ordered before unmounting /boot

* initialize the hostname from the fs label of /, if /etc/hostname does not exist?

* rename "userspace" to "core-os"

* syscall filter:
  - syscall filter: add knowledge about compat syscalls
  - syscall filter: don't enforce no new privs?
  - syscall filter: option to return EPERM rather than SIGSYS?
  - syscall filter: port to libseccomp
  - system-wide seccomp filter

* .device aliases need to be implemented with the "following" logic, probably.

* load-fragment: when loading a unit file via a chain of symlinks
  verify that it isn't masked via any of the names traversed.

* introduce Type=pid-file

* maybe allow services with ExecStop= set, but no ExecStart=?

* change Requires=basic.target to RequisiteOverride=basic.target

* support rd.luks.allow-discards= kernel cmdline params in cryptsetup generator

* drop accountsservice's StandardOutput=syslog and Type=dbus fields

* when breaking cycles drop sysv services first, then services from /run, then from /etc, then from /usr

* move passno parsing to fstab generator

* automount: implement expire:
   - set superblock timeout AUTOFS_DEV_IOCTL_TIMEOUT_CMD
   - periodically run AUTOFS_DEV_IOCTL_EXPIRE_CMD
     - every timeout/4 (original autofs logic)
     - blocking, needs a thread
     - run until -EAGAIN
   - receive expire packet on pipe if kernel tells the timeout is over
     - call umount
     - answer expire packet on pipe with AUTOFS_DEV_IOCTL_{READY,FAIL}_CMD
   - AUTOFS_DEV_IOCTL_EXPIRE_CMD returns

* services which create their own subcgroups break cgroup-empty notification (needs to be fixed in the kernel)

* ExecOnFailure=/usr/bin/foo

* ConditionSecurity= should learn about IMA and SMACK

* udev:
  - remove src/udev/udev-builtin-firmware.c (CONFIG_FW_LOADER_USER_HELPER=n)
  - move to LGPL
  - unify utf8 validator code with shared/
  - kill scsi_id
  - add trigger --subsystem-match=usb/usb_device device

* cleanup syslog 'priority' vs. 'level' wording

* dbus upstream still refers to dbus.target and shouldn't

* when a service has the same env var set twice we actually store it twice and return that in systemctl show -p... We should only show the last setting

* support container_ttys=

* introduce mix of BindTo and Requisite

* add DeleteSocketsOnStop=yes|no option to socket units

* There's currently no way to cancel fsck (used to be possible via C-c or c on the console)

* add option to sockets to avoid activation. Instead just drop packets/connections, see http://cyberelk.net/tim/2012/02/15/portreserve-systemd-solution/

* default unix qlen is too small (10). bump sysctl? add sockopt?

* figure out whether we should leave dbus around during shutdown

* dbus: in fedora, make /var/lib/dbus/machine-id a symlink to /etc/machine-id

* dbus: move dbus to early boot

* save coredump in Windows/Mozilla minidump format

* support crash reporting operation modes (https://live.gnome.org/GnomeOS/Design/Whiteboards/ProblemReporting)

* clean up session cgroups that remain after logout (think sshd), but eventually run empty

* when an instanced service exits, remove its parent cgroup too if possible.

* default to actual 32bit PIDs, via /proc/sys/kernel/pid_max

* be able to specify a forced restart of service A where service B depends on, in case B
  needs to be auto-respawned?

* when a bus name of a service disappears from the bus make sure to queue further activation requests

* tmpfiles: apply "x" on "D" too (see patch from William Douglas)

* for services: don't set $HOME in services unless requested

* hide PAM/TCPWrap options in fragment parser when compile time disabled

* when we automatically restart a service, ensure we restart its rdeps, too.

* allow Type=simple with PIDFile=
  https://bugzilla.redhat.com/show_bug.cgi?id=723942

* move PAM code into its own binary

* implement Register= switch in .socket units to enable registration
  in Avahi, RPC and other socket registration services.

* make sure systemd-ask-password-wall does not shutdown systemd-ask-password-console too early

* support sd_notify() style notification when reload begins (RELOADING=1), reload is finished (READY=1), and add ReloadSignal= then to use in combination

* support sd_notify() style notification when shutting down, to make auto-exit bus services work (STOPPING=1)

* verify that the AF_UNIX sockets of a service in the fs still exist
  when we start a service in order to avoid confusion when a user
  assumes starting a service is enough to make it accessible

* Make it possible to set the keymap independently from the font on
  the kernel cmdline. Right now setting one resets also the other.

* and a dbus call to generate target from current state

* readahead:
  - drop /.readahead on bigger upgrades with yum
  - move readahead files into /var (look for them with .path units?)
  - readahead: use BTRFS_IOC_DEFRAG_RANGE instead of BTRFS_IOC_DEFRAG ioctl, with START_IO
  - readahead: when bumping /sys readahead variable save mtime and compare later to detect changes
  - readahead: make use of EXT4_IOC_MOVE_EXT, as used by http://e4rat.sourceforge.net/

* add support for /bin/mount -s

* GC unreferenced jobs (such as .device jobs)

* write blog stories about:
  - hwdb: what belongs into it, lsusb
  - enabling dbus services
  - status update
  - how to make changes to sysctl and sysfs attributes
  - remote access
  - how to pass throw-away units to systemd, or dynamically change properties of existing units
  - how to integrate cgconfig and suchlike with systemd
  - testing with Harald's awesome test kit
  - auto-restart
  - how to develop against journal browsing APIs
  - the journal HTTP iface
  - non-cgroup resource management
  - dynamic resource management with cgroups
  - refreshed, longer missions statement
  - calendar time events
  - init=/bin/sh vs. "emergency" mode, vs. "rescue" mode, vs. "multi-user" mode, vs. "graphical" mode, and the debug shell
  - how to create your own target
  - instantiated apache, dovecot and so on
  - hooking a script into various stages of shutdown/rearly booot

* allow port=0 in .socket units

* support systemd.mask= on the kernel command line.

* reuse mkdtemp namespace dirs in /tmp?

* recreate systemd's D-Bus private socket file on SIGUSR2

* Support --test based on current system state

* investigate whether the gnome pty helper should be moved into systemd, to provide cgroup support.

* maybe introduce ExecRestartPre=

* dot output for --test showing the 'initial transaction'

* port over to LISTEN_FDS/LISTEN_PID:
   - rpcbind (/var/run/rpcbind.sock!) HAVEPATCH
   - cups     HAVEPATCH
   - postfix, saslauthd
   - apache/samba
   - libvirtd (/var/run/libvirt/libvirt-sock-ro)
   - bluetoothd (/var/run/sdp! @/org/bluez/audio!)
   - distccd

* fingerprint.target, wireless.target, gps.target, netdevice.target

* io priority during initialization

* drop cap bounding set in readahead and other services

* systemd-python:
   - figure out a simple way to wait for journal events in a way that
     works with ^C
   - add documentation to systemd.daemon

External:

* dbus:
   - dbus --user
   - natively watch for dbus-*.service symlinks (PENDING)
   - allow specification of socket mode/umask when allocating DBusServer
   - allow disabling of fd passing when connecting a AF_UNIX connection
   - allow disabling of UID passing for AUTH EXTERNAL
   - always pass cred data along each message
   - teach dbus to activate all services it finds in /etc/systemd/services/org-*.service

* fix alsa mixer restore to not print error when no config is stored

* make cryptsetup lower --iter-time

* patch kernel for xattr support in /dev, /proc/, /sys?

* NTP: the kernel's 11-minutes-mode syncs the system time to the RTC, but only
  in an ~30 minutes window. It does not adjust larger differences. Find a way
  to tell the kernel, to always do a full time sync when the RTC is in UTC and
  we are in 11-minutes-mode. When we trust the system time to NTP we also want
  the RTC to sync up.

* kernel: add device_type = "fb", "fbcon" to class "graphics"

* bootchart:
   - plot per-process IO utilization
   - group processes based on service association (cgroups)
   - document initcall_debug

Regularly:

* look for close() vs. close_nointr() vs. close_nointr_nofail()

* check for strerror(r) instead of strerror(-r)

* Use PR_SET_PROCTITLE_AREA if it becomes available in the kernel

* %m in printf() instead of strerror(errno);

* pahole

* set_put(), hashmap_put() return values check. i.e. == 0 doesn't free()!

* use secure_getenv() instead of getenv() where appropriate

* link up selected blog stories from man pages and unit files Documentation= fields

Scheduled for removal or fixing:

* xxxOverridable dependencies (probably: fix)