aboutsummaryrefslogtreecommitdiff
path: root/init
blob: bc1452c396c34ef5bb644011bb588d32e9b69885 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
#!/bin/bash

# Init script for build2 Build OS.
#
# Loosely based on the one that comes in Debian initrd.img (since we are
# using its kernel image).
#
trap "exit 1" ERR
set -o errtrace # Trap in functions.

# Note: diagnostics goes to stdout.
#
function info () { echo "$*"; }
function error ()
{
  if [ "$#" -gt 0 ]; then
    info "$*";
  fi

  # The setsid voodoo (taken from Debian init's panic()) is to enable job
  # control.
  #
  info "type Ctrl-D to exit shell and reboot"
  setsid /bin/bash -c "exec /bin/bash -i <>/dev/tty1 1>&0 2>&1"
  reboot -f
}

# Some pre-systemd utilities (like reboot) come from klibc-utils.
#
export PATH=/sbin:/usr/sbin:/bin:/usr/bin:/usr/lib/klibc/bin/

# One would expect rootflags=size=Xg to work but it doesn't (perhaps init
# is expected to interpret it)?
#
mount -o remount,size=2G /

mkdir -p /sys /proc
mount -t sysfs -o nodev,noexec,nosuid sysfs /sys
mount -t proc -o nodev,noexec,nosuid proc /proc

info "init starting up..."

mount -t devtmpfs -o noexec,nosuid,mode=0755 udev /dev
mkdir -p /dev/pts
mount -t devpts -o noexec,nosuid,gid=5,mode=0620 devpts /dev/pts || true

# If tmpfs size is unspecified, then the default is 50%. Note that for /tmp in
# particular we may (temporarily) utilize several gigabytes while building the
# toolchain.
#
mkdir -p /run
mount -t tmpfs -o nodev,noexec,nosuid,size=512M,mode=0755 tmpfs /run

mkdir -p /tmp
mount -t tmpfs -o nodev,nosuid,size=2G,mode=1777 tmpfs /tmp

# Start udev.
#
# Based on Debian initrd's init-{top,bottom}/udev
#
info "starting udev..."

if [ -w /sys/kernel/uevent_helper ]; then
  echo >/sys/kernel/uevent_helper
fi

SYSTEMD_LOG_LEVEL=info /lib/systemd/systemd-udevd --daemon --resolve-names=never

udevadm trigger --type=subsystems --action=add
udevadm trigger --type=devices --action=add
udevadm settle || true

# Detect hardware sensors.
#
sensors-detect --auto

# Initialize KVM.
#
#if ! (modprobe kvm_intel || modprobe kvm_amd); then
#  error "no virtualization support available (is it disabled in BIOS?)"
#fi

# Parse the kernel command line. This is complicated by the fact that the
# values can be quoted, for example:
#
# foo='foo fox'
# bar="bar 'box'"
#
# First we separete quoted variables and arguments with newlines (giving
# priority to assignments). Then we replace whitespaces with newline on
# lines that don't contain quotes. Finally, clean up by removing blank
# lines.
#
# Note: the same code as in buildos.
#
readarray -t cmdline < <(cat /proc/cmdline | \
  sed -r -e "s/([^ ]+=)?('[^']*'|\"[^\"]*\")/\n\1\2\n/g" | \
  sed -r -e "/['\"]/!s/ /\n/g" |
  sed -r -e '/^\s*$/d')

# Enter all buildos variables as bash variables.
#
info "command line:"
for v in "${cmdline[@]}"; do
  var="$(sed -n -re 's/^buildos\.([^=]+)=.*$/\1/p' <<<"$v")" # Extract name.

  if [ -n "$var" ]; then
    val="$(sed -re 's/^[^=]+=(.*)$/\1/' <<<"$v")"            # Extract value.
    val="$(sed -re "s/^('(.*)'|\"(.*)\")$/\2\3/" <<<"$val")" # Strip quoted.
    info "  $var=$val"

    # If the variable contains a dot, then it is a toolchain variable and we
    # don't care about those in init.
    #
    if [[ "$var" != *.* ]]; then
      declare "$var=$val"
    fi
  fi
done

# Figure out network configuration and generate the corresponding
# /etc/network/interfaces.
#
info "starting network..."

# We are using udev's predictable interface names. The two character prefixes
# based on the type of interface:
#
#  en -- ethernet
#  sl -- serial line IP (slip)
#  wl -- wlan
#  ww -- wwan
#
eth_all="$(cd /sys/class/net && ls -d en?*)"

if [ -z "$eth_all" ]; then
  info "no ethernet interfaces found among:"
  ip link show
  error
fi

eth=
eth_up=
for s in 1 2 4 8; do

  # Try to bring them all up and find the one that has carrier.
  #
  for i in $eth_all; do
    ip link set "$i" up || true
  done

  sleep "$s"

  for i in $eth_all; do
    if [ "$(cat "/sys/class/net/$i/carrier")" -eq "1" ]; then
      info "detected carrier on $i"
      eth_up+=" $i"
    fi
  done

  # Bring them all down.
  #
  for i in $eth_all; do
    ip link set "$i" down || true
  done

  # If we didn't find anything, try to wait for carrier longer.
  #
  if [ -z "$eth_up" ]; then
    continue
  fi

  # If we end up with several interfaces we simply unleash dhcp on all of
  # them and use the first that gets configured.
  #
  # Note also that it's possible the interface that we want is not yet ready
  # in which case we will try to wait for carrier a bit longer.
  #
  for i in $eth_up; do
    if dhclient -v "$i"; then
      eth="$i"
      break
    fi
  done

  if [ -n "$eth" ]; then
    break
  fi
done

if [ -z "$eth_up" ]; then
  info "no ethernet interfaces with carrier among:"
  ip link show
  error
fi

if [ -z "$eth" ]; then
  info "no ethernet interfaces with DHCP among:"
  ip link show
  error
fi

# Global and local MAC addresses (used below for br0 and br1, respectively).
# Derive the local address from the global by fixing the first octet to 02
# (locally-assigned).
#
gmac="$(cat "/sys/class/net/$eth/address")"
lmac="$(sed -re 's/..:(.+)/02:\1/g' <<<"$gmac")"

info "configured $eth ($gmac)"

# Machine id.
#
mid="$(sed -re 's/://g' <<<"$gmac")"

# Set the hostname.
#
hname="$(hostname)"
if [ "$hname" = "(none)" ]; then
  hname="build-$mid"
  hostname "$hname"
fi
echo "$hname" >/etc/hostname

info "hostname $hname"

# Stop DHCP client without releasing the lease and deconfigure the interface.
# The plan is to generate a bridge-based /etc/network/interfaces configuration
# based on what we have discovered and then let the systemd networking bringup
# to configure everything (at which point we will hopefully reuse the lease).
#
dhclient -x 2>/dev/null

# @@ Needs to be made configurable. Something like 172.23.0.0/16.
#
priv_network="172.23.0.0"
priv_netmask="255.255.0.0"
priv_netbase="$(sed -e 's/^\(.*\)\.0\.0$/\1/' <<<"$priv_network")"

# Note that if we don't assign the bridge MAC address, then it will keep
# changing every time an interface with a greater address (e.g., a tap)
# joins the bridge. Needless to say, constantly changing MAC will wreck
# all kinds of networking havoc.
#
cat <<EOF >/etc/network/interfaces
auto lo
iface lo inet loopback

# Public bridge.
#
auto br0
iface br0 inet dhcp
    bridge_ports   $eth
    bridge_stp     off
    bridge_maxwait 0
    bridge_fd      0
    bridge_hw      $gmac
    post-up ip link set $eth txqueuelen 4000
    post-up ip link set br0 txqueuelen 4000

# Private bridge with NAT to br0.
#
auto br1
iface br1 inet static
    address ${priv_netbase}.0.1
    netmask $priv_netmask
    bridge_ports   none
    bridge_stp     off
    bridge_maxwait 0
    bridge_fd      0
    bridge_hw      $lmac
    post-up ip link set br1 txqueuelen 4000
    post-up iptables -t nat -A POSTROUTING -o br0 -j MASQUERADE
    post-up iptables -A FORWARD -i br0 -o br1 -m state --state RELATED,ESTABLISHED -j ACCEPT
    post-up iptables -A FORWARD -i br1 -o br0 -j ACCEPT
EOF

cat <<EOF >/etc/dnsmasq.d/br1-dhcp
interface=br1
bind-interfaces
dhcp-range=${priv_netbase}.1.1,${priv_netbase}.255.255,$priv_netmask,2h
EOF

# Figure out disk configuration and generate the corresponding /etc/fstab.
#
fstab=/etc/fstab
#fstab=/dev/stdout

echo -n '' >$fstab

l=
state=
machines=
while read l || [ -n "$l" ]; do
  d="$(sed -re 's/.*NAME=\"([^\"]+)\".*/\1/'   <<<"$l")"
  t="$(sed -re 's/.*FSTYPE=\"([^\"]*)\".*/\1/' <<<"$l")"
  l="$(sed -re 's/.*LABEL=\"([^\"]*)\".*/\1/'  <<<"$l")"

  # Strip the buildos prefix from the label. If the result is empty then this
  # disk/patition hasn't been labeled for use by us.
  #
  l="$(sed -n -re 's/^buildos\.([^ ]+)$/\1/p' <<<"$l")"

  if [ -z "$l" ]; then
    continue
  fi

  # Handle buildos.state.
  #
  if [ "$l" == "state" ]; then

    if [ -n "$state" ]; then
      error "multiple disks labeled with buildos.state"
    fi

    if [ -z "$t" ]; then
      error "no filesystem on $d labeled with buildos.state"
    fi

    info "mounting $d (buildos.state) on /state as $t"

    # Check it.
    #
    if ! fsck -n -t "$t" "$d"; then
      info "$d (buildos.state) has errors; run fsck -t $type $d"
      error
    fi

    o="defaults,noatime,nodiratime"
    echo "$d /state $t $o 0 0" >>$fstab

    # Mount it now since we need it below.
    #
    mkdir -p "/state"
    mount -t "$t" -o "$o" "$d" /state

    state="true"
    continue
  fi

  # Handle buildos.machines and buildos.machines.* mounts.
  #
  if [[ "$l" == "machines" ]] || [[ "$l" =~ "machines.".+ ]]; then

    if [ "$t" != "btrfs" ]; then
      error "non-btrfs filesystem on $d labeled with buildos.machines"
    fi

    if [ "$l" = "machines" ]; then
      # Single mount.
      #
      if [ -n "$machines" ]; then
	error "multiple disks labeled with buildos.machines/machines.*"
      fi

      m=/build/machines/default
      machines="single"
    else
      # Multiple mounts.
      #
      if [ "$machines" = "single" ]; then
	error "multiple disks labeled with buildos.machines/machines.*"
      fi

      n="$(sed -n -re 's/^machines\.([^ ]+)$/\1/p' <<<"$l")"
      m="/build/machines/$n"
      machines="multiple"
    fi

    info "mounting $d (buildos.$l) on $m"

    # Check it.
    #
    if ! btrfs check -p "$d"; then
      info "$d (buildos.$l) has errors; run btrfs check -p --repair $d"
      error
    fi

    o="defaults,noatime,nodiratime,user_subvol_rm_allowed"
    echo "$d $m btrfs $o 0 0" >>$fstab

    # Mount it and change the owner of the filesystem root.
    #
    mkdir -p "$m"
    mount -t btrfs -o "$o" "$d" "$m"
    chown build:build "$m"

    continue
  fi
done < <(lsblk --pairs --paths --output NAME,FSTYPE,LABEL)
#done <<EOF
#NAME="/dev/sda" FSTYPE="btrfs" LABEL="buildos.machines.vol1"
#NAME="/dev/sdb" FSTYPE="btrfs" LABEL="buildos.machines.vol2"
#EOF

if [ -z "$state" ]; then
  info "no disks labaled with buildos.state among:"
  lsblk --paths --output NAME,TYPE,FSTYPE,SIZE,LABEL,UUID
  info "consider formatting and/or labelling a suitable disk"
  error
fi

if [ -z "$machines" ]; then
  info "no disks labaled with buildos.machines* among:"
  lsblk --paths --output NAME,TYPE,FSTYPE,SIZE,LABEL,UUID
  info "consider formatting and/or labelling a suitable disk"
  error
fi

# Create /build/tftp. We make it a size-limited tmpfs since potentially-
# compromized VMs will be able to upload to.
#
mkdir -p /build/tftp
o="nodev,noexec,nosuid,size=512M"
o+=",mode=0755,uid=$(id -u build),gid=$(id -g build)"
echo "tmpfs /build/tftp tmpfs $o 0 0" >>$fstab

# Generate a host key. Used, for example, by the bbot agent to authenticate
# with a controller.
#
mkdir -p /state/etc
if [ ! -e /state/etc/host-key.pem ]; then
  openssl genrsa 4096 >/state/etc/host-key.pem
fi

# Configure Postfix.
#
cat <<<"$hname" >/etc/mailname

sed -r -i \
 -e "s%^(myhostname).*%\1 = $hname%" \
 -e 's%^(mydestination).*%\1 = $myhostname, localhost.localdomain, localhost%' \
 -e 's%^(mynetworks).*%\1 = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128%' \
 -e "s%^(relayhost).*%\1 = $smtp_relay%" \
 /etc/postfix/main.cf

# Make admin alias for buildos.admin_email, alias root as admin.
#
cat <<EOF >>/etc/aliases
admin: $admin_email
root: admin
EOF
newaliases

# Configure OpenSSH server. Things that we do:
#
# - Change host key locations to (persistent) /state/etc/ssh/ and remove
#   existing keys. If no corresponding key exists in /state, generate it.
#
# - Disable root login.
#
# - Disable password authentication.
#
sed -r -i \
  -e "s%^#?HostKey +(.+)%HostKey /state\1%" \
  -e "s%^#?PermitRootLogin.*%PermitRootLogin no%" \
  -e "s%^#?PasswordAuthentication.*%PasswordAuthentication no%" \
 /etc/ssh/sshd_config

# Generate missing keys.
#
mkdir -p /state/etc/ssh
for k in $(echo /etc/ssh/ssh_host_*_key | \
	      sed -re 's%/etc/ssh/ssh_host_([^_]+)_key%\1%g'); do
  if [ ! -e "/state/etc/ssh/ssh_host_${k}_key" ]; then
    ssh-keygen -N "" -t "$k" -f "/state/etc/ssh/ssh_host_${k}_key"
  fi
done
rm -f /etc/ssh/ssh_host_*_key*

# Add buildos.ssh_key to build's authorized_keys.
#
if [ -n "$ssh_key" ]; then
  info "adding buildos.ssh_key to ~build/.ssh/authorized_keys"
  mkdir -p /build/.ssh
  echo "$ssh_key" >>/build/.ssh/authorized_keys

  chown build:build /build/.ssh /build/.ssh/authorized_keys
  chmod 700 /build/.ssh
  chmod 600 /build/.ssh/authorized_keys
fi

# Configure the TFTP server (tftpd-hpa).
#
# We could have ran it as user 'build' but since it is read-only, the default
# user 'tftp' works just as well. Note that by default it is running chroot'ed
# (--secure) so no symlinks pointing outside /build/tftp will work.
#
sed -r -i \
  -e "s%^(TFTP_DIRECTORY).*%\1=\"/build/tftp\"%" \
 /etc/default/tftpd-hpa

# Hand off to systemd. But first arrange to keep console output (which
# becomes tty1).
#
mkdir -p /etc/systemd/system/getty@tty1.service.d
cat <<EOF >/etc/systemd/system/getty@tty1.service.d/noclear.conf
[Service]
TTYVTDisallocate=no
EOF

# Stop udev daemon (systemd will start its own).
#
udevadm control --exit

# Get rid of klibc tools.
#
export PATH=/sbin:/usr/sbin:/bin:/usr/bin

exec /lib/systemd/systemd \
  --show-status=1 \
  --machine-id="00000000000000000000$mid" \
  </dev/console >/dev/console 2>&1