Rework immutability and overlays
This commit is contained in:
Rudra Saraswat
parent
fddf7f86ae
commit
5e65e6c06e
13 changed files with 1141 additions and 70 deletions
2
.gitignore
vendored
2
.gitignore
vendored
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@ -2,3 +2,5 @@
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/blend-settings/build/
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/blend-settings/dist/
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/blend-settings/package-lock.json
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*.o
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/overlayfs-tools/overlayfs-tools
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@ -18,7 +18,7 @@
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Containers</button>
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<button class="btn btn-outline-light shadow-none d-none" id="android-button" onclick="page('android')">Android
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Apps</button>
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<button class="btn btn-outline-light shadow-none" id="system-button" onclick="page('system')">System</button>
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<!-- <button class="btn btn-outline-light shadow-none" id="system-button" onclick="page('system')">System</button> -->
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</div>
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</div>
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53
blend-system
53
blend-system
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@ -70,51 +70,39 @@ def info(msg):
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def error(err):
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print (colors.bold + colors.fg.red + '>> e: ' + colors.reset + colors.bold + err + colors.reset)
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def load_prev_state():
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subprocess.call(['rm', '-rf', '/blend/overlay/current'], stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
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subprocess.call(['mkdir', '-p', '/blend/overlay/current/usr'], stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
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subprocess.call(['tar', '-xvpzf', f'/blend/states/state{current_state()}.tar.gz', '-C', '/blend/overlay/current/usr', '--numeric-owner'],
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stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
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subprocess.call(['rm', '-f', f'/blend/states/state{current_state()}.tar.gz'], stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
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### END
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def current_state():
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_state = -1
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for s in os.listdir('/blend/states'):
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if re.match(r'^state([0-9]+)\.tar\.gz$', s):
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for s in os.listdir('/.states'):
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if re.match(r'^state([0-9]+)\.squashfs$', s):
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if int(s[5:-7]) > _state:
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_state = int(s[5:-7])
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return _state
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def save_state():
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subprocess.call(['mkdir', '-p', '/blend/states'], stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
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subprocess.call(['mkdir', '-p', '/.states'], stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
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state = current_state() + 1
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subprocess.call(r"find /blend/states/ -type f -not -name 'state" + str(state - 1) + ".tar.gz' -print0 | xargs -0 -I {} rm {}", stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL, shell=True)
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subprocess.call(['tar', '-C', '/blend/overlay/current/usr', '-cpzf', f'/blend/states/state{state}.tar.gz', '.'], stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
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subprocess.call(['bash', '-c', 'rm -f /.states/*.tmp'])
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if subprocess.call(['mksquashfs', '/usr', f'/.states/state{state}.squashfs.tmp', '-no-compression'], stdout=sys.stdout, stderr=sys.stderr) == 0:
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subprocess.call(['rm', '-rf', 'add-squashfs'], cwd='/tmp')
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subprocess.call(['mkdir', '-p', 'add-squashfs'], cwd='/tmp')
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subprocess.call(['cp', '-a', '/var/lib', 'add-squashfs/varlib'], cwd='/tmp')
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if subprocess.call(['mksquashfs', 'add-squashfs', f'/.states/state{state}.squashfs.tmp', '-no-compression'], cwd='/tmp') == 0:
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subprocess.call(['mv', f'/.states/state{state}.squashfs.tmp', f'/.states/state{state}.squashfs'])
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else:
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error('state creation failed')
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exit(1)
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else:
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error('state creation failed')
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exit(1)
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info(f'saved state {state}')
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def autosave_state():
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while True:
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if not os.path.isfile('/blend/states/.disable_states'):
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save_state()
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time.sleep(12*60*60) # XXX: make this configurable
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def toggle_states():
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if os.path.isfile('/blend/states/.disable_states'):
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os.remove('/blend/states/.disable_states')
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info('enabled saving states automatically (every 6 hours; this will be configurable in future releases)')
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else:
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subprocess.call(['touch', '/blend/states/.disable_states'], stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
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info('disabled saving states automatically')
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def rollback():
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if current_state() == -1:
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error('no states present')
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exit(1)
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subprocess.call(['touch', '/blend/states/.load_prev_state'], stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
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info(f'will rollback to the previous state on the next boot')
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info("Rollback hasn't been implemented yet.")
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description = f'''
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{colors.bold}{colors.fg.purple}Usage:{colors.reset}
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@ -126,7 +114,6 @@ description = f'''
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{colors.bold}help{colors.reset} Show this help message and exit.
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{colors.bold}version{colors.reset} Show version information and exit.
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{colors.bold}save-state{colors.reset} Save the current state (backup).
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{colors.bold}toggle-states{colors.reset} Enable/disable automatic state creation (you can still manually save states).
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{colors.bold}rollback{colors.reset} Rollback to previous state.
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{colors.bold}{colors.fg.purple}options for commands{colors.reset}:
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@ -142,8 +129,6 @@ parser = argparse.ArgumentParser(description=description, usage=argparse.SUPPRES
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command_map = { 'help': 'help',
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'version': 'version',
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'save-state': save_state,
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'toggle-states': toggle_states,
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'autosave-state': autosave_state,
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'rollback': rollback }
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parser.add_argument('command', choices=command_map.keys(), help=argparse.SUPPRESS)
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parser.add_argument('-v', '--version', action='version', version=f'%(prog)s {__version}', help=argparse.SUPPRESS)
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@ -1,10 +0,0 @@
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[Unit]
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Description=Save system state
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[Service]
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Type=simple
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ExecStart=/usr/bin/blend-system autosave-state
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User=root
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[Install]
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WantedBy=multi-user.target
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72
blend.hook
Normal file → Executable file
72
blend.hook
Normal file → Executable file
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@ -1,30 +1,56 @@
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#!/bin/bash
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run_latehook() {
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if [[ -f /new_root/blend/states/.load_prev_state ]] && compgen -G "/new_root/blend/states/state+([0-9]).tar.gz" >/dev/null; then
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rm -rf /new_root/blend/overlay/current
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mkdir -p /new_root/blend/overlay/current/usr
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c=0
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for i in $(compgen -G "/new_root/blend/states/state*.tar.gz"); do
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n="${i:19:-7}"
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if [[ "$n" -gt "$c" ]]; then
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c="$n"
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echo
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if [[ "$abort_staging" == true ]]; then
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echo '[ BLEND ] Not applying system changes made in previous boot.'
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rm -rf '/new_root/.upperdir' '/new_root/.workdir'; mkdir -p '/new_root/.upperdir' '/new_root/.workdir'
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fi
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if [[ -d "/new_root/blend/overlay/current" ]]; then
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echo '[ BLEND ] Detected old version of overlay implementation, switching.'
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rm -rf /new_root/.upperdir /new_root/.workdir
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mv /new_root/blend/overlay/current/usr /new_root/.upperdir
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rm -rf /new_root/blend
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fi
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# Broken attempt at getting rollback and snapshots working.
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#
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# if [[ -L "/new_root/.states/rollback.squashfs" ]] && [[ -e "/new_root/.states/rollback.squashfs" ]]; then
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# echo -n '[ BLEND ] Rolling back to selected state. Do __not__ power off or reboot.'
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# echo
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# cd /new_root
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# unsquashfs /new_root/.states/rollback.squashfs && (
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# for i in bin include lib lib32 share src; do
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# rm -rf rm -rf /new_root/.workdir/"$i" rm -rf /new_root/.upperdir/"$i" /new_root/usr/"$i"
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# mv squashfs-root/"$i" /new_root/usr
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# done
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# rm -rf /new_root/.workdir/varlib /new_root/.upperdir/varlib /new_root/var/lib
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# mkdir -p /new_root/var/lib
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# mv squashfs-root/varlib /new_root/var/varlib
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# echo ' - SUCCESS '
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# echo
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# ); cd ..
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# fi
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for i in bin include lib lib32 share src; do
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echo -n "[ BLEND ] Setting up /usr/${i} overlay (applying changes)."
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rm -rf /new_root/.workdir/"$i"
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mkdir -p /new_root/.upperdir/"$i" /new_root/.workdir/"$i" /new_root/usr/"$i" /new_root/tmp
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cd /new_root/tmp; overlayfs-tools merge -l /new_root/usr/$i -u /new_root/.upperdir/$i &>/dev/null; chmod 755 ./overlay-tools-*; ./overlay-tools-* &>/dev/null; rm -f ./overlay-tools-*; cd /
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mkdir -p /new_root/.upperdir/"$i"
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mount -t overlay overlay -o 'lowerdir=/new_root/usr/'$i',upperdir=/new_root/.upperdir/'$i',workdir=/new_root/.workdir/'$i /new_root/usr/"$i" -o index=off
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echo " - SUCCESS"
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done
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tar -xvpzf "/new_root/blend/states/state${c}.tar.gz" -C "/new_root/blend/overlay/current/usr" --numeric-owner &>/dev/null
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rm -f "/new_root/blend/states/state${c}.tar.gz" "/new_root/blend/states/.load_prev_state"
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fi
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mkdir -p /new_root/blend/overlay/current/usr/bin \
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/new_root/blend/overlay/current/usr/sbin \
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/new_root/blend/overlay/current/usr/share
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mkdir -p /new_root/usr/bin \
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/new_root/usr/sbin \
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/new_root/usr/share
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rm -rf /new_root/blend/overlay/workdir_1 /new_root/blend/overlay/workdir_2 /new_root/blend/overlay/workdir_3
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mkdir -p /new_root/blend/overlay/workdir_1 /new_root/blend/overlay/workdir_2 /new_root/blend/overlay/workdir_3
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mount -t overlay overlay -o 'lowerdir=/new_root/usr/bin,upperdir=/new_root/blend/overlay/current/usr/bin,workdir=/new_root/blend/overlay/workdir_1' /new_root/usr/bin -o index=off
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mount -t overlay overlay -o 'lowerdir=/new_root/usr/sbin,upperdir=/new_root/blend/overlay/current/usr/sbin,workdir=/new_root/blend/overlay/workdir_2' /new_root/usr/sbin -o index=off
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mount -t overlay overlay -o 'lowerdir=/new_root/usr/share,upperdir=/new_root/blend/overlay/current/usr/share,workdir=/new_root/blend/overlay/workdir_3' /new_root/usr/share -o index=off
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echo
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echo -n "[ BLEND ] Setting up /var/lib overlay (applying changes)."
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rm -rf /new_root/.workdir/varlib
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mkdir -p /new_root/.upperdir/varlib /new_root/.workdir/varlib /new_root/var/lib /new_root/tmp
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cd /new_root/tmp; overlayfs-tools merge -l /new_root/var/lib -u /new_root/.upperdir/varlib &>/dev/null; chmod 755 ./overlay-tools-*; ./overlay-tools-* &>/dev/null; rm -f ./overlay-tools-*; cd /
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mkdir -p /new_root/.upperdir/varlib
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mount -t overlay overlay -o 'lowerdir=/new_root/var/lib,upperdir=/new_root/.upperdir/varlib,workdir=/new_root/.workdir/varlib' /new_root/var/lib -o index=off
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echo ' - SUCCESS'
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echo
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}
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@ -5,12 +5,13 @@ build() {
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add_module overlay
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add_binary bash
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add_binary tar
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add_binary overlayfs-tools
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add_runscript
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}
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help() {
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cat <<HELPEOF
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This provides a support for mounting the blend /usr overlay. No
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This provides a support for mounting the blend overlays. No
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configuration is needed.
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HELPEOF
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}
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42
overlayfs-tools/README.md
Executable file
42
overlayfs-tools/README.md
Executable file
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@ -0,0 +1,42 @@
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overlayfs-tools
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========
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[OverlayFS](https://www.kernel.org/doc/Documentation/filesystems/overlayfs.txt) is the union filesystem provided by Linux kernel.
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This program comes provides three tools:
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- **vacuum** - remove duplicated files in `upperdir` where `copy_up` is done but the file is not actually modified (see the sentence "the `copy_up` may turn out to be unnecessary" in the [Linux documentation](https://www.kernel.org/doc/Documentation/filesystems/overlayfs.txt)). This may reduce the size of `upperdir` without changing `lowerdir` or `overlay`.
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- **diff** - show the list of actually changed files (the difference between `overlay` and `lowerdir`). A file with its type changed (i.e. from symbolic link to regular file) will shown as deleted then added, rather than modified. Similarly, for a opaque directory in `upperdir`, the corresponding directory in `lowerdir` (if exists) will be shown as entirely deleted, and a new directory with the same name added. File permission/owner changes will be simply shown as modified.
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- **merge** - merge down the changes from `upperdir` to `lowerdir`. Unlike [aubrsync](http://aufs.sourceforge.net/aufs2/brsync/README.txt) for AuFS which bypasses the union filesystem mechanism, overlayfs-utils emulates the OverlayFS logic, which will be far more efficient. After this operation, `upperdir` will be empty and `lowerdir` will be the same as original `overlay`.
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- **deref** - copy changes from `upperdir` to `uppernew` while unfolding redirect directories and metacopy regular files, so that new upperdir is compatible with legacy overlayfs driver.
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For safety reasons, vacuum and merge will not actually modify the filesystem, but generate a shell script to do the changes instead.
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Prerequisite and Building
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--------
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$ make
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Example usage
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--------
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# ./overlay diff -l /lower -u /upper
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See `./overlay --help` for more.
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Why sudo
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--------
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As [Linux documentation](https://www.kernel.org/doc/Documentation/filesystems/overlayfs.txt) said,
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> A directory is made opaque by setting the xattr "trusted.overlay.opaque" to "y".
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However, only users with `CAP_SYS_ADMIN` can read `trusted.*` extended attributes.
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Warnings / limitations
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--------
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- Only works for regular files and directories. Do not use it on OverlayFS with device files, socket files, etc..
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- Hard links may be broken (i.e. resulting in duplicated independent files).
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- File owner, group and permission bits will be preserved. File timestamps, attributes and extended attributes might be lost.
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- This program only works for OverlayFS with only one lower layer.
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- It is recommended to have the OverlayFS unmounted before running this program.
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581
overlayfs-tools/logic.c
Executable file
581
overlayfs-tools/logic.c
Executable file
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@ -0,0 +1,581 @@
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#define _GNU_SOURCE
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#include <stdio.h>
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#include <fcntl.h>
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#include <sys/stat.h>
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#include <linux/limits.h>
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#include <stdlib.h>
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#include <string.h>
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#include <errno.h>
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#include <unistd.h>
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#include <sys/xattr.h>
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#include <fts.h>
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#include <libgen.h>
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#include "logic.h"
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#include "sh.h"
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// exactly the same as in linux/fs.h
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#define WHITEOUT_DEV 0
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// exact the same as in fs/overlayfs/overlayfs.h
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const char *ovl_opaque_xattr = "trusted.overlay.opaque";
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const char *ovl_redirect_xattr = "trusted.overlay.redirect";
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const char *ovl_metacopy_xattr = "trusted.overlay.metacopy";
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#define MIN(X,Y) ((X) < (Y) ? (X) : (Y))
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#define TRAILING_SLASH(ftype) (((ftype) == S_IFDIR) ? "/" : "")
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static inline mode_t file_type(const struct stat *status) {
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return status->st_mode & S_IFMT;
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}
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const char *ftype_name(mode_t type) {
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switch (type) {
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case S_IFDIR:
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return "directory";
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case S_IFREG:
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return "regular file";
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case S_IFLNK:
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return "symbolic link";
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default:
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return "special file";
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}
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}
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const char *ftype_name_plural(mode_t type) {
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switch (type) {
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case S_IFDIR:
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return "Directories";
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case S_IFREG:
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return "Files";
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case S_IFLNK:
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return "Symbolic links";
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default:
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return "Special files";
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}
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}
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static inline bool is_whiteout(const struct stat *status) {
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return (file_type(status) == S_IFCHR) && (status->st_rdev == WHITEOUT_DEV);
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}
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static inline mode_t permission_bits(const struct stat *status) { // not used yet. I haven't decided how to treat permission bit changes
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return status->st_mode & (S_IRWXU | S_IRWXG | S_IRWXO | S_ISVTX);
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}
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int is_opaque(const char *path, bool *output) {
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char val;
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ssize_t res = getxattr(path, ovl_opaque_xattr, &val, 1);
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if ((res < 0) && (errno != ENODATA)) {
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return -1;
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}
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*output = (res == 1 && val == 'y');
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return 0;
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}
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int is_redirect(const char *path, bool *output) {
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ssize_t res = getxattr(path, ovl_redirect_xattr, NULL, 0);
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if ((res < 0) && (errno != ENODATA)) {
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fprintf(stderr, "File %s redirect xattr can not be read.\n", path);
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return -1;
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}
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*output = (res > 0);
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return 0;
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}
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int is_metacopy(const char *path, bool *output) {
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ssize_t res = getxattr(path, ovl_metacopy_xattr, NULL, 0);
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if ((res < 0) && (errno != ENODATA)) {
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fprintf(stderr, "File %s metacopy xattr can not be read.\n", path);
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return -1;
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}
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*output = (res >= 0);
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return 0;
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}
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// Treat redirect as opaque dir because it hides the tree in lower_path
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// and we do not support following to redirected lower path
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int is_opaquedir(const char *path, bool *output) {
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bool opaque, redirect;
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if (is_opaque(path, &opaque) < 0) { return -1; }
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if (is_redirect(path, &redirect) < 0) { return -1; }
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*output = opaque || redirect;
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return 0;
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}
|
||||
|
||||
bool permission_identical(const struct stat *lower_status, const struct stat *upper_status) {
|
||||
return (permission_bits(lower_status) == permission_bits(upper_status)) && (lower_status->st_uid == upper_status->st_uid) && (lower_status->st_gid == upper_status->st_gid);
|
||||
}
|
||||
|
||||
int read_chunk(int fd, char *buf, int len) {
|
||||
ssize_t ret;
|
||||
ssize_t remain = len;
|
||||
while (remain > 0 && (ret = read(fd, buf, remain)) != 0) {
|
||||
if (ret == -1) {
|
||||
if (errno == EINTR) {
|
||||
continue;
|
||||
}
|
||||
return -1;
|
||||
}
|
||||
remain -= ret;
|
||||
buf += ret;
|
||||
}
|
||||
return len - remain;
|
||||
}
|
||||
|
||||
int regular_file_identical(const char *lower_path, const struct stat *lower_status, const char *upper_path, const struct stat *upper_status, bool *output) {
|
||||
size_t blksize = (size_t) MIN(lower_status->st_blksize, upper_status->st_blksize);
|
||||
if (lower_status->st_size != upper_status->st_size) { // different sizes
|
||||
*output = false;
|
||||
return 0;
|
||||
}
|
||||
bool metacopy, redirect;
|
||||
if (is_metacopy(upper_path, &metacopy) < 0) { return -1; }
|
||||
if (is_redirect(upper_path, &redirect) < 0) { return -1; }
|
||||
if (metacopy) {
|
||||
// metacopy means data is indentical, but redirect means it is not identical to lower_path
|
||||
*output = !redirect;
|
||||
return 0;
|
||||
}
|
||||
char lower_buffer[blksize];
|
||||
char upper_buffer[blksize];
|
||||
int lower_file = open(lower_path, O_RDONLY);
|
||||
int upper_file = open(upper_path, O_RDONLY);
|
||||
if (lower_file < 0) {
|
||||
fprintf(stderr, "File %s can not be read for content.\n", lower_path);
|
||||
return -1;
|
||||
}
|
||||
if (upper_file < 0) {
|
||||
fprintf(stderr, "File %s can not be read for content.\n", upper_path);
|
||||
return -1;
|
||||
}
|
||||
ssize_t read_lower; ssize_t read_upper;
|
||||
do { // we can assume one will not reach EOF earlier than the other, as the file sizes are checked to be the same earlier
|
||||
read_lower = read_chunk(lower_file, lower_buffer, blksize);
|
||||
read_upper = read_chunk(upper_file, upper_buffer, blksize);
|
||||
if (read_lower < 0) {
|
||||
fprintf(stderr, "Error occured when reading file %s.\n", lower_path);
|
||||
return -1;
|
||||
}
|
||||
if (read_upper < 0) {
|
||||
fprintf(stderr, "Error occured when reading file %s.\n", upper_path);
|
||||
return -1;
|
||||
}
|
||||
if (read_upper != read_lower) { // this should not happen as we've checked the sizes
|
||||
fprintf(stderr, "Unexpected size difference: %s.\n", upper_path);
|
||||
return -1;
|
||||
}
|
||||
if (memcmp(lower_buffer, upper_buffer, read_upper)) { *output = false; return 0; } // the output is by default false, but we still set it for ease of reading
|
||||
} while (read_lower || read_upper);
|
||||
*output = true; // now we can say they are identical
|
||||
if (close(lower_file) || close(upper_file)) { return -1; }
|
||||
return 0;
|
||||
}
|
||||
|
||||
int symbolic_link_identical(const char *lower_path, const char *upper_path, bool *output) {
|
||||
char lower_buffer[PATH_MAX];
|
||||
char upper_buffer[PATH_MAX];
|
||||
ssize_t lower_len = readlink(lower_path, lower_buffer, PATH_MAX);
|
||||
ssize_t upper_len = readlink(upper_path, upper_buffer, PATH_MAX);
|
||||
if (lower_len < 0 || lower_len == PATH_MAX) {
|
||||
fprintf(stderr, "Symbolic link %s cannot be resolved.\n", lower_path);
|
||||
return -1;
|
||||
}
|
||||
if (upper_len < 0 || upper_len == PATH_MAX) {
|
||||
fprintf(stderr, "Symbolic link %s cannot be resolved.\n", upper_path);
|
||||
return -1;
|
||||
}
|
||||
lower_buffer[lower_len] = '\0';
|
||||
upper_buffer[upper_len] = '\0';
|
||||
*output = (strcmp(lower_buffer, upper_buffer) == 0);
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int vacuum_d(const char *lower_path, const char* upper_path, const size_t lower_root_len, const struct stat *lower_status, const struct stat *upper_status, FILE* script_stream, int *fts_instr) {
|
||||
bool opaque;
|
||||
if (is_opaquedir(upper_path, &opaque) < 0) { return -1; }
|
||||
if (opaque) { // TODO: sometimes removing opaque directory (and combine with lower directory) might be better
|
||||
*fts_instr = FTS_SKIP;
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int vacuum_dp(const char *lower_path, const char* upper_path, const size_t lower_root_len, const struct stat *lower_status, const struct stat *upper_status, FILE* script_stream, int *fts_instr) {
|
||||
if (lower_status == NULL) { return 0; } // lower does not exist
|
||||
if (file_type(lower_status) != S_IFDIR) { return 0; }
|
||||
if (!permission_identical(lower_status, upper_status)) { return 0; }
|
||||
bool opaque;
|
||||
if (is_opaquedir(upper_path, &opaque) < 0) {
|
||||
return -1;
|
||||
}
|
||||
if (opaque) { return 0; }
|
||||
// this directory might be empty if all children are deleted in previous commands. but we simply don't test whether it's that case
|
||||
return command(script_stream, "rmdir --ignore-fail-on-non-empty %U", upper_path);
|
||||
}
|
||||
|
||||
static int vacuum_f(const char *lower_path, const char* upper_path, const size_t lower_root_len, const struct stat *lower_status, const struct stat *upper_status, FILE* script_stream, int *fts_instr) {
|
||||
if (lower_status == NULL) { return 0; } // lower does not exist
|
||||
if (file_type(lower_status) != S_IFREG) { return 0; }
|
||||
if (!permission_identical(lower_status, upper_status)) { return 0; }
|
||||
bool identical;
|
||||
if (regular_file_identical(lower_path, lower_status, upper_path, upper_status, &identical) < 0) {
|
||||
return -1;
|
||||
}
|
||||
if (!identical) { return 0; }
|
||||
return command(script_stream, "rm %U", upper_path);
|
||||
}
|
||||
|
||||
static int vacuum_sl(const char *lower_path, const char* upper_path, const size_t lower_root_len, const struct stat *lower_status, const struct stat *upper_status, FILE* script_stream, int *fts_instr) {
|
||||
if (lower_status == NULL) { return 0; } // lower does not exist
|
||||
if (file_type(lower_status) != S_IFLNK) { return 0; }
|
||||
if (!permission_identical(lower_status, upper_status)) { return 0; }
|
||||
bool identical;
|
||||
if (symbolic_link_identical(lower_path, upper_path, &identical) < 0) {
|
||||
return -1;
|
||||
}
|
||||
if (!identical) { return 0; }
|
||||
return command(script_stream, "rm %U", upper_path);
|
||||
}
|
||||
|
||||
void print_only_in(const char *path) {
|
||||
char *dirc = strdup(path);
|
||||
char *basec = strdup(path);
|
||||
char *dname = dirname(dirc);
|
||||
char *bname = basename(basec);
|
||||
printf("Only in %s: %s\n", dname, bname);
|
||||
free(dirc);
|
||||
free(basec);
|
||||
}
|
||||
|
||||
void print_removed(const char *lower_path, const size_t lower_root_len, mode_t lower_type) {
|
||||
if (brief) {
|
||||
print_only_in(lower_path);
|
||||
} else {
|
||||
printf("Removed: %s%s\n", &lower_path[lower_root_len], TRAILING_SLASH(lower_type));
|
||||
}
|
||||
}
|
||||
|
||||
void print_added(const char *lower_path, const size_t lower_root_len, const char *upper_path, mode_t upper_type) {
|
||||
if (brief) {
|
||||
print_only_in(upper_path);
|
||||
} else {
|
||||
printf("Added: %s%s\n", &lower_path[lower_root_len], TRAILING_SLASH(upper_type));
|
||||
}
|
||||
}
|
||||
|
||||
void print_replaced(const char *lower_path, const size_t lower_root_len, mode_t lower_type, const char *upper_path, mode_t upper_type) {
|
||||
if (brief) {
|
||||
printf("File %s is a %s while file %s is a %s\n", lower_path, ftype_name(lower_type), upper_path, ftype_name(upper_type));
|
||||
} else {
|
||||
if (lower_type != S_IFDIR) { // dir removed already printed by list_deleted_files()
|
||||
print_removed(lower_path, lower_root_len, lower_type);
|
||||
}
|
||||
print_added(lower_path, lower_root_len, upper_path, upper_type);
|
||||
}
|
||||
}
|
||||
|
||||
void print_modified(const char *lower_path, const size_t lower_root_len, mode_t lower_type, const char *upper_path, bool identical) {
|
||||
if (brief) {
|
||||
if (!identical) { // brief format does not print permission difference
|
||||
printf("%s %s and %s differ\n", ftype_name_plural(lower_type), lower_path, upper_path);
|
||||
}
|
||||
} else {
|
||||
printf("Modified: %s%s\n", &lower_path[lower_root_len], TRAILING_SLASH(lower_type));
|
||||
}
|
||||
}
|
||||
|
||||
int list_deleted_files(const char *lower_path, size_t lower_root_len, mode_t upper_type) { // This WORKS with files and itself is listed. However, prefixs are WRONG!
|
||||
// brief format needs to print only first level deleted children under opaque dir
|
||||
bool children = (brief && (upper_type == S_IFDIR));
|
||||
if (!verbose && !children) {
|
||||
if (!brief || upper_type == S_IFCHR) { // dir replaced already printed by print_replaced()
|
||||
print_removed(lower_path, lower_root_len, S_IFDIR);
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
FTSENT *cur;
|
||||
char *paths[2] = {(char *) lower_path, NULL };
|
||||
FTS *ftsp = fts_open(paths, FTS_NOCHDIR | FTS_PHYSICAL, NULL);
|
||||
if (ftsp == NULL) { return -1; }
|
||||
int return_val = 0;
|
||||
while (((cur = fts_read(ftsp)) != NULL) && (return_val == 0)) {
|
||||
switch (cur->fts_info) {
|
||||
case FTS_D:
|
||||
// brief format does not need to print deleted grand children under opaque dir
|
||||
if (children && cur->fts_level > 0) {
|
||||
print_removed(cur->fts_path, lower_root_len, S_IFDIR);
|
||||
fts_set(ftsp, cur, FTS_SKIP);
|
||||
}
|
||||
break; // do nothing
|
||||
case FTS_DP:
|
||||
// brief format does not need to print deleted dir under opaque dir itself
|
||||
if (!children) {
|
||||
print_removed(cur->fts_path, lower_root_len, S_IFDIR);
|
||||
}
|
||||
break;
|
||||
case FTS_F:
|
||||
print_removed(cur->fts_path, lower_root_len, S_IFREG);
|
||||
break;
|
||||
case FTS_SL:
|
||||
print_removed(cur->fts_path, lower_root_len, S_IFLNK);
|
||||
break;
|
||||
case FTS_DEFAULT:
|
||||
fprintf(stderr, "File %s is a special file (device or pipe). We cannot handle that.\n", cur->fts_path);
|
||||
return_val = -1;
|
||||
break;
|
||||
default:
|
||||
fprintf(stderr, "Error occured when opening %s.\n", cur->fts_path);
|
||||
return_val = -1;
|
||||
}
|
||||
}
|
||||
if (errno) { return_val = -1; } // if no error happened, fts_read will "sets the external variable errno to 0" according to the documentation
|
||||
return fts_close(ftsp) || return_val;
|
||||
}
|
||||
|
||||
static int diff_d(const char *lower_path, const char* upper_path, const size_t lower_root_len, const struct stat *lower_status, const struct stat *upper_status, FILE* script_stream, int *fts_instr) {
|
||||
bool opaque = false;
|
||||
bool lower_exist = (lower_status != NULL);
|
||||
if (lower_exist) {
|
||||
if (file_type(lower_status) == S_IFDIR) {
|
||||
if (is_opaquedir(upper_path, &opaque) < 0) { return -1; }
|
||||
if (opaque) {
|
||||
if (list_deleted_files(lower_path, lower_root_len, S_IFDIR) < 0) { return -1; }
|
||||
} else {
|
||||
if (!permission_identical(lower_status, upper_status)) {
|
||||
print_modified(lower_path, lower_root_len, S_IFDIR, upper_path, true);
|
||||
}
|
||||
return 0; // children must be recursed, and directory itself does not need to be printed
|
||||
}
|
||||
} else { // other types of files
|
||||
print_replaced(lower_path, lower_root_len, file_type(lower_status), upper_path, S_IFDIR);
|
||||
}
|
||||
}
|
||||
if (!(verbose || (brief && opaque))) { // brief format needs to print children of opaque dir
|
||||
*fts_instr = FTS_SKIP;
|
||||
}
|
||||
if (!lower_exist || (!brief && opaque)) { // brief format does not need to print opaque dir itself
|
||||
print_added(lower_path, lower_root_len, upper_path, S_IFDIR);
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int diff_f(const char *lower_path, const char* upper_path, const size_t lower_root_len, const struct stat *lower_status, const struct stat *upper_status, FILE* script_stream, int *fts_instr) {
|
||||
bool identical;
|
||||
if (lower_status != NULL) {
|
||||
switch (file_type(lower_status)) {
|
||||
case S_IFREG:
|
||||
if (regular_file_identical(lower_path, lower_status, upper_path, upper_status, &identical) < 0) {
|
||||
return -1;
|
||||
}
|
||||
if (!(identical && permission_identical(lower_status, upper_status))) {
|
||||
print_modified(lower_path, lower_root_len, S_IFREG, upper_path, identical);
|
||||
}
|
||||
return 0;
|
||||
case S_IFDIR:
|
||||
if (list_deleted_files(lower_path, lower_root_len, S_IFREG) < 0) { return -1; }
|
||||
/* fallthrough */
|
||||
case S_IFLNK:
|
||||
print_replaced(lower_path, lower_root_len, file_type(lower_status), upper_path, S_IFREG);
|
||||
return 0;
|
||||
default:
|
||||
fprintf(stderr, "File %s is a special file (device or pipe). We cannot handle that.\n", lower_path);
|
||||
return -1;
|
||||
}
|
||||
}
|
||||
print_added(lower_path, lower_root_len, upper_path, S_IFREG);
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int diff_sl(const char *lower_path, const char* upper_path, const size_t lower_root_len, const struct stat *lower_status, const struct stat *upper_status, FILE* script_stream, int *fts_instr) {
|
||||
bool identical;
|
||||
if (lower_status != NULL) {
|
||||
switch (file_type(lower_status)) {
|
||||
case S_IFDIR:
|
||||
if (list_deleted_files(lower_path, lower_root_len, S_IFLNK) < 0) { return -1; }
|
||||
/* fallthrough */
|
||||
case S_IFREG:
|
||||
print_replaced(lower_path, lower_root_len, file_type(lower_status), upper_path, S_IFLNK);
|
||||
return 0;
|
||||
case S_IFLNK:
|
||||
if (symbolic_link_identical(lower_path, upper_path, &identical) < 0) {
|
||||
return -1;
|
||||
}
|
||||
if (!(identical && permission_identical(lower_status, upper_status))) {
|
||||
print_modified(lower_path, lower_root_len, S_IFLNK, upper_path, identical);
|
||||
}
|
||||
return 0;
|
||||
default:
|
||||
fprintf(stderr, "File %s is a special file (device or pipe). We cannot handle that.\n", lower_path);
|
||||
return -1;
|
||||
}
|
||||
}
|
||||
print_added(lower_path, lower_root_len, upper_path, S_IFLNK);
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int diff_whiteout(const char *lower_path, const char* upper_path, const size_t lower_root_len, const struct stat *lower_status, const struct stat *upper_status, FILE* script_stream, int *fts_instr) {
|
||||
if (lower_status != NULL) {
|
||||
if (file_type(lower_status) == S_IFDIR) {
|
||||
if (list_deleted_files(lower_path, lower_root_len, S_IFCHR) < 0) { return -1; }
|
||||
} else {
|
||||
print_removed(lower_path, lower_root_len, file_type(lower_status));
|
||||
}
|
||||
} // else: whiteouting a nonexistent file? must be an error. but we ignore that :)
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int merge_d(const char *lower_path, const char* upper_path, const size_t lower_root_len, const struct stat *lower_status, const struct stat *upper_status, FILE* script_stream, int *fts_instr) {
|
||||
bool redirect;
|
||||
if (is_redirect(upper_path, &redirect) < 0) { return -1; }
|
||||
// merging redirects is not supported, we must abort merge so redirected lower (under whiteout) won't be deleted
|
||||
// upper_path may be hiding the directory in lower_path, but there may be another redirect upper pointing at it
|
||||
if (redirect) {
|
||||
fprintf(stderr, "Found redirect on %s. Merging redirect is not supported - Abort.\n", upper_path);
|
||||
return -1;
|
||||
}
|
||||
if (lower_status != NULL) {
|
||||
if (file_type(lower_status) == S_IFDIR) {
|
||||
bool opaque = false;
|
||||
if (is_opaquedir(upper_path, &opaque) < 0) { return -1; }
|
||||
if (opaque) {
|
||||
if (command(script_stream, "rm -r %L", lower_path) < 0) { return -1; };
|
||||
} else {
|
||||
if (!permission_identical(lower_status, upper_status)) {
|
||||
command(script_stream, "chmod --reference %U %L", upper_path, lower_path);
|
||||
}
|
||||
return 0; // children must be recursed, and directory itself does not need to be printed
|
||||
}
|
||||
} else {
|
||||
command(script_stream, "rm %L", lower_path);
|
||||
}
|
||||
}
|
||||
*fts_instr = FTS_SKIP;
|
||||
return command(script_stream, "mv -T %U %L", upper_path, lower_path);
|
||||
}
|
||||
|
||||
static int merge_dp(const char *lower_path, const char* upper_path, const size_t lower_root_len, const struct stat *lower_status, const struct stat *upper_status, FILE* script_stream, int *fts_instr) {
|
||||
if (lower_status != NULL) {
|
||||
if (file_type(lower_status) == S_IFDIR) {
|
||||
bool opaque = false;
|
||||
if (is_opaquedir(upper_path, &opaque) < 0) { return -1; }
|
||||
if (!opaque) { // delete the directory: it should be empty already
|
||||
return command(script_stream, "rmdir %U", upper_path);
|
||||
}
|
||||
}
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int merge_f(const char *lower_path, const char* upper_path, const size_t lower_root_len, const struct stat *lower_status, const struct stat *upper_status, FILE* script_stream, int *fts_instr) {
|
||||
bool metacopy, redirect;
|
||||
if (is_metacopy(upper_path, &metacopy) < 0) { return -1; }
|
||||
if (is_redirect(upper_path, &redirect) < 0) { return -1; }
|
||||
// merging metacopy is not supported, we must abort merge so lower data won't be deleted
|
||||
if (metacopy || redirect) {
|
||||
fprintf(stderr, "Found metacopy/redirect on %s. Merging metacopy/redirect is not supported - Abort.\n", upper_path);
|
||||
return -1;
|
||||
}
|
||||
return command(script_stream, "rm -rf %L", lower_path) || command(script_stream, "mv -T %U %L", upper_path, lower_path);
|
||||
}
|
||||
|
||||
static int merge_sl(const char *lower_path, const char* upper_path, const size_t lower_root_len, const struct stat *lower_status, const struct stat *upper_status, FILE* script_stream, int *fts_instr) {
|
||||
return command(script_stream, "rm -rf %L", lower_path) || command(script_stream, "mv -T %U %L", upper_path, lower_path);
|
||||
}
|
||||
|
||||
static int merge_whiteout(const char *lower_path, const char* upper_path, const size_t lower_root_len, const struct stat *lower_status, const struct stat *upper_status, FILE* script_stream, int *fts_instr) {
|
||||
return command(script_stream, "rm -r %L", lower_path) || command(script_stream, "rm %U", upper_path);
|
||||
}
|
||||
|
||||
typedef int (*TRAVERSE_CALLBACK)(const char *lower_path, const char* upper_path, const size_t lower_root_len, const struct stat *lower_status, const struct stat *upper_status, FILE* script_stream, int *fts_instr);
|
||||
|
||||
int traverse(const char *lower_root, const char *upper_root, FILE* script_stream, TRAVERSE_CALLBACK callback_d, TRAVERSE_CALLBACK callback_dp, TRAVERSE_CALLBACK callback_f, TRAVERSE_CALLBACK callback_sl, TRAVERSE_CALLBACK callback_whiteout) { // returns 0 on success
|
||||
FTSENT *cur;
|
||||
char *paths[2] = {(char *) upper_root, NULL };
|
||||
char lower_path[PATH_MAX];
|
||||
strcpy(lower_path, lower_root);
|
||||
size_t upper_root_len = strlen(upper_root);
|
||||
size_t lower_root_len = strlen(lower_root);
|
||||
FTS *ftsp = fts_open(paths, FTS_NOCHDIR | FTS_PHYSICAL, NULL);
|
||||
if (ftsp == NULL) { return -1; }
|
||||
int return_val = 0;
|
||||
while ((return_val == 0) && ((cur = fts_read(ftsp)) != NULL)) {
|
||||
TRAVERSE_CALLBACK callback = NULL;
|
||||
switch (cur->fts_info) {
|
||||
case FTS_D:
|
||||
callback = callback_d;
|
||||
break;
|
||||
case FTS_DP:
|
||||
callback = callback_dp;
|
||||
break;
|
||||
case FTS_F:
|
||||
callback = callback_f;
|
||||
break;
|
||||
case FTS_SL:
|
||||
callback = callback_sl;
|
||||
break;
|
||||
case FTS_DEFAULT:
|
||||
if (is_whiteout(cur->fts_statp)) {
|
||||
callback = callback_whiteout;
|
||||
} else {
|
||||
return_val = -1;
|
||||
fprintf(stderr, "File %s is a special file (device or pipe). We cannot handle that.\n", cur->fts_path);
|
||||
}
|
||||
break;
|
||||
default:
|
||||
return_val = -1;
|
||||
fprintf(stderr, "Error occured when opening %s.\n", cur->fts_path);
|
||||
}
|
||||
if (callback != NULL) {
|
||||
int fts_instr = 0;
|
||||
struct stat lower_status;
|
||||
bool lower_exist = true;
|
||||
strcpy(&lower_path[lower_root_len], &(cur->fts_path[upper_root_len]));
|
||||
if (lstat(lower_path, &lower_status) != 0) {
|
||||
if (errno == ENOENT || errno == ENOTDIR) { // the corresponding lower file (or its ancestor) does not exist at all
|
||||
lower_exist = false;
|
||||
} else { // stat failed for some unknown reason
|
||||
fprintf(stderr, "Failed to stat %s.\n", lower_path);
|
||||
return_val = -1;
|
||||
break; // do not call callback in this case
|
||||
}
|
||||
}
|
||||
return_val = callback(lower_path, cur->fts_path, lower_root_len, lower_exist ? &lower_status : NULL, cur->fts_statp, script_stream, &fts_instr); // return_val must previously be 0
|
||||
if (fts_instr) {
|
||||
fts_set(ftsp, cur, fts_instr);
|
||||
}
|
||||
}
|
||||
}
|
||||
if (errno) { return_val = -1; } // if no error happened, fts_read will "sets the external variable errno to 0" according to the documentation
|
||||
return fts_close(ftsp) || return_val;
|
||||
}
|
||||
|
||||
static int deref_d(const char *mnt_path, const char* upper_path, const size_t mnt_root_len, const struct stat *mnt_status, const struct stat *upper_status, FILE* script_stream, int *fts_instr) {
|
||||
bool redirect;
|
||||
if (is_redirect(upper_path, &redirect) < 0) { return -1; }
|
||||
if (!redirect) { return 0; }
|
||||
*fts_instr = FTS_SKIP;
|
||||
return command(script_stream, "rm -rf %U", upper_path) || command(script_stream, "cp -a %M %U", mnt_path, upper_path);
|
||||
}
|
||||
|
||||
static int deref_f(const char *mnt_path, const char* upper_path, const size_t mnt_root_len, const struct stat *mnt_status, const struct stat *upper_status, FILE* script_stream, int *fts_instr) {
|
||||
bool metacopy;
|
||||
if (is_metacopy(upper_path, &metacopy) < 0) { return -1; }
|
||||
if (!metacopy) { return 0; }
|
||||
return command(script_stream, "rm -r %U", upper_path) || command(script_stream, "cp -a %M %U", mnt_path, upper_path);
|
||||
}
|
||||
|
||||
int vacuum(const char* lowerdir, const char* upperdir, FILE* script_stream) {
|
||||
return traverse(lowerdir, upperdir, script_stream, vacuum_d, vacuum_dp, vacuum_f, vacuum_sl, NULL);
|
||||
}
|
||||
|
||||
int diff(const char* lowerdir, const char* upperdir) {
|
||||
return traverse(lowerdir, upperdir, NULL, diff_d, NULL, diff_f, diff_sl, diff_whiteout);
|
||||
}
|
||||
|
||||
int merge(const char* lowerdir, const char* upperdir, FILE* script_stream) {
|
||||
return traverse(lowerdir, upperdir, script_stream, merge_d, merge_dp, merge_f, merge_sl, merge_whiteout);
|
||||
}
|
||||
|
||||
int deref(const char* mountdir, const char* upperdir, FILE* script_stream) {
|
||||
return traverse(mountdir, upperdir, script_stream, deref_d, NULL, deref_f, NULL, NULL);
|
||||
}
|
||||
37
overlayfs-tools/logic.h
Executable file
37
overlayfs-tools/logic.h
Executable file
|
|
@ -0,0 +1,37 @@
|
|||
/*
|
||||
* logic.h / logic.c
|
||||
*
|
||||
* the logic for the three feature functions
|
||||
*/
|
||||
|
||||
#ifndef OVERLAYFS_TOOLS_LOGIC_H
|
||||
#define OVERLAYFS_TOOLS_LOGIC_H
|
||||
|
||||
#include <stdbool.h>
|
||||
|
||||
extern bool verbose;
|
||||
extern bool brief;
|
||||
|
||||
/*
|
||||
* feature function. will take very long time to complete. returns 0 on success
|
||||
*/
|
||||
int vacuum(const char* lowerdir, const char* upperdir, FILE* script_stream);
|
||||
|
||||
/*
|
||||
* feature function. will take very long time to complete. returns 0 on success
|
||||
*/
|
||||
int diff(const char* lowerdir, const char* upperdir);
|
||||
|
||||
/*
|
||||
* feature function. will take very long time to complete. returns 0 on success
|
||||
*/
|
||||
int merge(const char* lowerdir, const char* upperdir, FILE* script_stream);
|
||||
|
||||
/*
|
||||
* Unfold metacopy and redirect upper.
|
||||
*
|
||||
* mountdir is required and lowerdir is irrelevant.
|
||||
*/
|
||||
int deref(const char* mountdir, const char* upperdir, FILE* script_stream);
|
||||
|
||||
#endif //OVERLAYFS_TOOLS_LOGIC_H
|
||||
266
overlayfs-tools/main.c
Executable file
266
overlayfs-tools/main.c
Executable file
|
|
@ -0,0 +1,266 @@
|
|||
/*
|
||||
* main.c
|
||||
*
|
||||
* the command line user interface
|
||||
*/
|
||||
#define _GNU_SOURCE
|
||||
#include <unistd.h>
|
||||
#include <errno.h>
|
||||
#include <stdio.h>
|
||||
#include <stdlib.h>
|
||||
#include <string.h>
|
||||
#include <getopt.h>
|
||||
#include <linux/limits.h>
|
||||
#include <stdbool.h>
|
||||
#include <sys/stat.h>
|
||||
#include <sys/xattr.h>
|
||||
#include <errno.h>
|
||||
#ifndef _SYS_STAT_H
|
||||
#include <linux/stat.h>
|
||||
#endif
|
||||
#include "logic.h"
|
||||
#include "sh.h"
|
||||
|
||||
#define STRING_BUFFER_SIZE PATH_MAX * 2
|
||||
|
||||
// currently, brief and verbose are mutually exclusive
|
||||
bool verbose;
|
||||
bool brief;
|
||||
bool yes;
|
||||
|
||||
void print_help(const char *program) {
|
||||
printf("Usage: %s command options\n", program);
|
||||
puts("");
|
||||
puts("Commands:");
|
||||
puts(" vacuum - remove duplicated files in upperdir where copy_up is done but the file is not actually modified");
|
||||
puts(" diff - show the list of actually changed files");
|
||||
puts(" merge - merge all changes from upperdir to lowerdir, and clear upperdir");
|
||||
puts(" deref - copy changes from upperdir to a new upperdir unfolding redirect and metacopy");
|
||||
puts("");
|
||||
puts("Options:");
|
||||
puts(" -l, --lowerdir=LOWERDIR the lowerdir of OverlayFS (required)");
|
||||
puts(" -u, --upperdir=UPPERDIR the upperdir of OverlayFS (required)");
|
||||
puts(" -m, --mountdir=MOUNTDIR the mountdir of OverlayFS (optional)");
|
||||
puts(" -L, --lowernew=LOWERNEW the lowerdir of new OverlayFS (optional)");
|
||||
puts(" -U, --uppernew=UPPERNEW the upperdir of new OverlayFS (optional)");
|
||||
puts(" -y --yes don't prompt if OverlayFS is still mounted (optional)");
|
||||
puts(" -v, --verbose with diff action only: when a directory only exists in one version, still list every file of the directory");
|
||||
puts(" -b, --brief with diff action only: conform to output of diff --brief --recursive --no-dereference");
|
||||
puts(" -h, --help show this help text");
|
||||
puts("");
|
||||
puts("See https://github.com/kmxz/overlayfs-tools/ for warnings and more information.");
|
||||
}
|
||||
|
||||
bool starts_with(const char *haystack, const char* needle) {
|
||||
return strncmp(needle, haystack, strlen(needle)) == 0;
|
||||
}
|
||||
|
||||
bool is_mounted(const char *lower, const char *upper) {
|
||||
FILE *f = fopen("/proc/mounts", "r");
|
||||
if (!f) {
|
||||
fprintf(stderr, "Cannot read /proc/mounts to test whether OverlayFS is mounted.\n");
|
||||
return true;
|
||||
}
|
||||
char buf[STRING_BUFFER_SIZE];
|
||||
while (fgets(buf, STRING_BUFFER_SIZE, f)) {
|
||||
if (!starts_with(buf, "overlay")) {
|
||||
continue;
|
||||
}
|
||||
if (strlen(buf) == STRING_BUFFER_SIZE) {
|
||||
fprintf(stderr, "OverlayFS line in /proc/mounts is too long.\n");
|
||||
return true;
|
||||
}
|
||||
char *m_lower = strstr(buf, "lowerdir=");
|
||||
char *m_upper = strstr(buf, "upperdir=");
|
||||
if (m_lower == NULL || m_upper == NULL) {
|
||||
fprintf(stderr, "Cannot extract information from OverlayFS line in /proc/mounts.\n");
|
||||
return true;
|
||||
}
|
||||
m_lower = &(m_lower[strlen("lowerdir=")]);
|
||||
m_upper = &(m_upper[strlen("upperdir=")]);
|
||||
if (!(strncmp(lower, m_lower, strlen(lower)) && strncmp(upper, m_upper, strlen(upper)))) {
|
||||
printf("The OverlayFS involved is still mounted.\n");
|
||||
return true;
|
||||
}
|
||||
}
|
||||
return false;
|
||||
}
|
||||
|
||||
bool check_mounted(const char *lower, const char *upper) {
|
||||
if (is_mounted(lower, upper) && !yes) {
|
||||
printf("It is strongly recommended to unmount OverlayFS first. Still continue (not recommended)?: \n");
|
||||
int r = getchar();
|
||||
if (r != 'Y' && r != 'y') {
|
||||
return true;
|
||||
}
|
||||
}
|
||||
return false;
|
||||
}
|
||||
|
||||
bool directory_exists(const char *path) {
|
||||
struct stat sb;
|
||||
if (lstat(path, &sb) != 0) { return false; }
|
||||
return (sb.st_mode & S_IFMT) == S_IFDIR;
|
||||
}
|
||||
|
||||
bool directory_create(const char *name, const char *path) {
|
||||
if (mkdir(path, 0755) == 0 || errno == EEXIST) { return true; }
|
||||
fprintf(stderr, "%s directory '%s' does not exist and cannot be created.\n", name, path);
|
||||
exit(EXIT_FAILURE);
|
||||
}
|
||||
|
||||
bool real_check_xattr_trusted(const char *tmp_path, int tmp_file) {
|
||||
int ret = fsetxattr(tmp_file, "trusted.overlay.test", "naive", 5, 0);
|
||||
close(tmp_file);
|
||||
if (ret) { return false; }
|
||||
char verify_buffer[10];
|
||||
if (getxattr(tmp_path, "trusted.overlay.test", verify_buffer, 10) != 5) { return false; }
|
||||
return !strncmp(verify_buffer, "naive", 5);
|
||||
}
|
||||
|
||||
bool check_xattr_trusted(const char *upper) {
|
||||
char tmp_path[PATH_MAX];
|
||||
strcpy(tmp_path, upper);
|
||||
strcat(tmp_path, "/.xattr_test_XXXXXX.tmp");
|
||||
int tmp_file = mkstemps(tmp_path, 4);
|
||||
if (tmp_file < 0) { return false; }
|
||||
bool ret = real_check_xattr_trusted(tmp_path, tmp_file);
|
||||
unlink(tmp_path);
|
||||
return ret;
|
||||
}
|
||||
|
||||
int main(int argc, char *argv[]) {
|
||||
|
||||
char *lower = NULL;
|
||||
char *upper = NULL;
|
||||
char *dir, *mnt = NULL;
|
||||
|
||||
static struct option long_options[] = {
|
||||
{ "lowerdir", required_argument, 0, 'l' },
|
||||
{ "upperdir", required_argument, 0, 'u' },
|
||||
{ "mountdir", required_argument, 0, 'm' },
|
||||
{ "lowernew", required_argument, 0, 'L' },
|
||||
{ "uppernew", required_argument, 0, 'U' },
|
||||
{ "yes", no_argument , 0, 'y' },
|
||||
{ "help", no_argument , 0, 'h' },
|
||||
{ "verbose", no_argument , 0, 'v' },
|
||||
{ "brief", no_argument , 0, 'b' },
|
||||
{ 0, 0, 0, 0 }
|
||||
};
|
||||
|
||||
int opt = 0;
|
||||
int long_index = 0;
|
||||
while ((opt = getopt_long_only(argc, argv, "l:u:m:L:U:yhvb", long_options, &long_index)) != -1) {
|
||||
switch (opt) {
|
||||
case 'l':
|
||||
lower = realpath(optarg, NULL);
|
||||
if (lower) { vars[LOWERDIR] = lower; }
|
||||
break;
|
||||
case 'u':
|
||||
upper = realpath(optarg, NULL);
|
||||
if (upper) { vars[UPPERDIR] = upper; }
|
||||
break;
|
||||
case 'm':
|
||||
mnt = realpath(optarg, NULL);
|
||||
if (mnt) { vars[MOUNTDIR] = mnt; }
|
||||
break;
|
||||
case 'L':
|
||||
directory_create("New lowerdir", optarg);
|
||||
dir = realpath(optarg, NULL);
|
||||
if (dir) { vars[LOWERNEW] = dir; }
|
||||
break;
|
||||
case 'U':
|
||||
directory_create("New upperdir", optarg);
|
||||
dir = realpath(optarg, NULL);
|
||||
if (dir) { vars[UPPERNEW] = dir; }
|
||||
break;
|
||||
case 'y':
|
||||
yes = true;
|
||||
break;
|
||||
case 'h':
|
||||
print_help(argv[0]);
|
||||
return EXIT_SUCCESS;
|
||||
case 'v':
|
||||
verbose = true;
|
||||
brief = false;
|
||||
break;
|
||||
case 'b':
|
||||
verbose = false;
|
||||
brief = true;
|
||||
break;
|
||||
default:
|
||||
fprintf(stderr, "Option %c is not supported.\n", opt);
|
||||
goto see_help;
|
||||
}
|
||||
}
|
||||
|
||||
if (!lower) {
|
||||
fprintf(stderr, "Lower directory not specified.\n");
|
||||
goto see_help;
|
||||
}
|
||||
if (!directory_exists(lower)) {
|
||||
fprintf(stderr, "Lower directory cannot be opened.\n");
|
||||
goto see_help;
|
||||
}
|
||||
if (!upper) {
|
||||
fprintf(stderr, "Upper directory not specified.\n");
|
||||
goto see_help;
|
||||
}
|
||||
if (!directory_exists(upper)) {
|
||||
fprintf(stderr, "Upper directory cannot be opened.\n");
|
||||
goto see_help;
|
||||
}
|
||||
if (!check_xattr_trusted(upper)) {
|
||||
fprintf(stderr, "The program cannot write trusted.* xattr. Try run again as root.\n");
|
||||
return EXIT_FAILURE;
|
||||
}
|
||||
// Relax check for mounted overlay if we are not going to modify lowerdir/upperdir
|
||||
if ((!vars[LOWERNEW] || !vars[UPPERNEW]) && check_mounted(lower, upper)) {
|
||||
return EXIT_FAILURE;
|
||||
}
|
||||
|
||||
if (optind == argc - 1) {
|
||||
int out;
|
||||
char filename_template[] = "overlay-tools-XXXXXX.sh";
|
||||
FILE *script = NULL;
|
||||
if (strcmp(argv[optind], "diff") == 0) {
|
||||
out = diff(lower, upper);
|
||||
} else if (strcmp(argv[optind], "vacuum") == 0) {
|
||||
script = create_shell_script(filename_template);
|
||||
if (script == NULL) { fprintf(stderr, "Script file cannot be created.\n"); return EXIT_FAILURE; }
|
||||
out = vacuum(lower, upper, script);
|
||||
} else if (strcmp(argv[optind], "merge") == 0) {
|
||||
script = create_shell_script(filename_template);
|
||||
if (script == NULL) { fprintf(stderr, "Script file cannot be created.\n"); return EXIT_FAILURE; }
|
||||
out = merge(lower, upper, script);
|
||||
} else if (strcmp(argv[optind], "deref") == 0) {
|
||||
if (!mnt || !vars[UPPERNEW]) { fprintf(stderr, "'deref' command requires --uppernew and --mountdir.\n"); return EXIT_FAILURE; }
|
||||
if (!directory_exists(mnt)) {
|
||||
fprintf(stderr, "OverlayFS mount directory cannot be opened.\n");
|
||||
goto see_help;
|
||||
}
|
||||
script = create_shell_script(filename_template);
|
||||
if (script == NULL) { fprintf(stderr, "Script file cannot be created.\n"); return EXIT_FAILURE; }
|
||||
out = deref(mnt, upper, script);
|
||||
} else {
|
||||
fprintf(stderr, "Action not supported.\n");
|
||||
goto see_help;
|
||||
}
|
||||
if (script != NULL) {
|
||||
printf("The script %s is created. Run the script to do the actual work please. Remember to run it when the OverlayFS is not mounted.\n", filename_template);
|
||||
fclose(script);
|
||||
}
|
||||
if (out) {
|
||||
fprintf(stderr, "Action aborted due to fatal error.\n");
|
||||
return EXIT_FAILURE;
|
||||
}
|
||||
return EXIT_SUCCESS;
|
||||
}
|
||||
|
||||
fprintf(stderr, "Please specify one action.\n");
|
||||
|
||||
see_help:
|
||||
fprintf(stderr, "Try '%s --help' for more information.\n", argv[0]);
|
||||
return EXIT_FAILURE;
|
||||
|
||||
}
|
||||
23
overlayfs-tools/makefile
Executable file
23
overlayfs-tools/makefile
Executable file
|
|
@ -0,0 +1,23 @@
|
|||
CC = gcc
|
||||
CFLAGS = -Wall -std=c99
|
||||
LDFLAGS = -lm
|
||||
ifneq (,$(wildcard /etc/alpine-release))
|
||||
LDFLAGS += -lfts
|
||||
endif
|
||||
|
||||
all: overlayfs-tools
|
||||
|
||||
overlayfs-tools: main.o logic.o sh.o
|
||||
$(CC) main.o logic.o sh.o -o overlayfs-tools $(LDFLAGS)
|
||||
|
||||
main.o: main.c logic.h
|
||||
$(CC) $(CFLAGS) -c main.c
|
||||
|
||||
logic.o: logic.c logic.h sh.h
|
||||
$(CC) $(CFLAGS) -c logic.c
|
||||
|
||||
sh.o: sh.c sh.h
|
||||
$(CC) $(CFLAGS) -c sh.c
|
||||
|
||||
clean:
|
||||
$(RM) main.o logic.o sh.o overlayfs-tools
|
||||
98
overlayfs-tools/sh.c
Executable file
98
overlayfs-tools/sh.c
Executable file
|
|
@ -0,0 +1,98 @@
|
|||
#define _GNU_SOURCE
|
||||
#include <stdarg.h>
|
||||
#include <stdlib.h>
|
||||
#include <stdio.h>
|
||||
#include <string.h>
|
||||
#include <sys/stat.h>
|
||||
#include <time.h>
|
||||
#include "sh.h"
|
||||
|
||||
char * vars[NUM_VARS];
|
||||
const char * var_names[NUM_VARS] = {
|
||||
"LOWERDIR",
|
||||
"UPPERDIR",
|
||||
"MOUNTDIR",
|
||||
"LOWERNEW",
|
||||
"UPPERNEW",
|
||||
};
|
||||
|
||||
int quote(const char *filename, FILE *output);
|
||||
|
||||
FILE* create_shell_script(char *tmp_path_buffer) {
|
||||
int tmp_file = mkstemps(tmp_path_buffer, 3); // the 3 is for suffix length (".sh")
|
||||
if (tmp_file < 0) { return NULL; }
|
||||
fchmod(tmp_file, S_IRWXU); // chmod to 0700
|
||||
FILE* f = fdopen(tmp_file, "w");
|
||||
if (f == NULL) { return NULL; }
|
||||
fprintf(f, "#!/usr/bin/env bash\n");
|
||||
fprintf(f, "set -x\n");
|
||||
time_t rawtime;
|
||||
time (&rawtime);
|
||||
fprintf(f, "# This shell script is generated by overlayfs-tools on %s\n", ctime (&rawtime));
|
||||
for (int i=0; i < NUM_VARS; i++) {
|
||||
if (vars[i]) {
|
||||
fprintf(f, "%s=", var_names[i]);
|
||||
if (quote(vars[i], f) < 0) { return NULL; }
|
||||
if (fputc('\n', f) == EOF) { return NULL; }
|
||||
}
|
||||
}
|
||||
// Non-empty *NEW vars make a backup copy and override *DIR vars
|
||||
if (vars[LOWERNEW]) {
|
||||
fprintf(f, "rm -rf \"$LOWERNEW\"\n");
|
||||
fprintf(f, "cp -a \"$LOWERDIR\" \"$LOWERNEW\"\n");
|
||||
fprintf(f, "LOWERDIR=");
|
||||
if (quote(vars[LOWERNEW], f) < 0) { return NULL; }
|
||||
if (fputc('\n', f) == EOF) { return NULL; }
|
||||
}
|
||||
if (vars[UPPERNEW]) {
|
||||
fprintf(f, "rm -rf \"$UPPERNEW\"\n");
|
||||
fprintf(f, "cp -a \"$UPPERDIR\" \"$UPPERNEW\"\n");
|
||||
fprintf(f, "UPPERDIR=");
|
||||
if (quote(vars[UPPERNEW], f) < 0) { return NULL; }
|
||||
if (fputc('\n', f) == EOF) { return NULL; }
|
||||
}
|
||||
return f;
|
||||
}
|
||||
|
||||
int quote(const char *filename, FILE *output) {
|
||||
if (fputc('\'', output) == EOF) { return -1; }
|
||||
for (const char *s = filename; *s != '\0'; s++) {
|
||||
if (*s == '\'') {
|
||||
if (fprintf(output, "'\"'\"'") < 0) { return -1; }
|
||||
} else {
|
||||
if (fputc(*s, output) == EOF) { return -1; }
|
||||
}
|
||||
}
|
||||
if (fputc('\'', output) == EOF) { return -1; }
|
||||
return 0;
|
||||
}
|
||||
|
||||
int substitue(char what, const char *filename, FILE *output) {
|
||||
int i;
|
||||
for (i=0; i < NUM_VARS; i++)
|
||||
if (vars[i] && var_names[i][0] == what)
|
||||
break;
|
||||
if (i == NUM_VARS) { return -1; }
|
||||
// filename prefix must match the var value
|
||||
int prefix = strlen(vars[i]);
|
||||
if (strncmp(filename, vars[i], prefix)) { return -1; }
|
||||
filename += prefix;
|
||||
fprintf(output, "\"$%s\"", var_names[i]);
|
||||
return quote(filename, output);
|
||||
}
|
||||
|
||||
int command(FILE *output, const char *command_format, ...) {
|
||||
va_list arg;
|
||||
va_start(arg, command_format);
|
||||
for (size_t i = 0; command_format[i] != '\0'; i++) {
|
||||
if (command_format[i] == '%') {
|
||||
const char *s = va_arg(arg, char *);
|
||||
if (substitue(command_format[++i], s, output) < 0) { return -1; }
|
||||
} else {
|
||||
if (fputc(command_format[i], output) == EOF) { return -1; }
|
||||
}
|
||||
}
|
||||
va_end(arg);
|
||||
if (fputc('\n', output) == EOF) { return -1; }
|
||||
return 0;
|
||||
}
|
||||
20
overlayfs-tools/sh.h
Executable file
20
overlayfs-tools/sh.h
Executable file
|
|
@ -0,0 +1,20 @@
|
|||
#ifndef OVERLAYFS_TOOLS_SH_H
|
||||
#define OVERLAYFS_TOOLS_SH_H
|
||||
|
||||
enum {
|
||||
LOWERDIR,
|
||||
UPPERDIR,
|
||||
MOUNTDIR,
|
||||
LOWERNEW,
|
||||
UPPERNEW,
|
||||
NUM_VARS
|
||||
};
|
||||
|
||||
extern const char *var_names[NUM_VARS];
|
||||
extern char *vars[NUM_VARS];
|
||||
|
||||
FILE* create_shell_script(char *tmp_path_buffer);
|
||||
|
||||
int command(FILE *output, const char *command_format, ...);
|
||||
|
||||
#endif //OVERLAYFS_TOOLS_SH_H
|
||||
Loading…
Reference in a new issue