Commit Graph

67 Commits

Author SHA1 Message Date
ceamac cbec986e78 Split config.yaml into global+persistent files; add -c/--config-file
config.yaml now holds only the global section (log-level, unshare-*,
with-veth, with-ipv6); a new persistent.yaml holds volumes/networks.
load_config_file()/write_config_file() are replaced by
load_global_config()/load_persistent_config()/write_global_config()/
write_persistent_config(), each touching only their own file.

-c/--config-file <path> lets one invocation use an alternate file for the
global section only -- persistent.yaml is always the one fixed path,
regardless of -c, so an experiment can never affect real volumes/networks
(a -c file's own volumes/networks, if any, are simply never read either).
A -c path that doesn't exist is a hard error, unlike the default path's
existing missing-file leniency.

migrate_legacy_config_if_needed() moves volumes/networks out of an
old-format config.yaml into persistent.yaml on first run after upgrading,
always against the fixed default paths regardless of -c. A name collision
aborts the migration for that run (touching neither file) rather than
risking data loss.

Required reordering main() to parse CLI args before loading config (so
-c's value is known first) -- ParsedArgs::log_level_flag_given tracks
whether --log-level was already given so the config file's own log-level
doesn't clobber it despite the reversed call order.
2026-09-05 09:32:36 +00:00
ceamac d2d631117d Drop -m/-u/-c short options for --mount/--umount/--cleanup
Now that -r/--run and -x/--exec cover normal use, --mount/--umount/--cleanup
are debug-only escape hatches not worth a short letter. Reassigned their
long_options codes to long-option-only constants (options::mount/umount/
cleanup) and dropped m:/u:/c: from getopt_long's own short-options string.

Updated the fixture smoke test (tests/run_test.py) and docs, which invoked
-m/-u/-c directly.
2026-09-05 08:43:58 +00:00
ceamac cdf9dcd210 Add global.with-veth/with-ipv6 config defaults for -n/--network creation
Replaces --no-ipv6/--no-veth (plain flags) with --with-ipv6/--with-veth,
each taking an explicit true/false value (e.g. --with-veth=false), parsed
via the same parse_bool_flag() the config file itself already uses (now
exported from config_file.h so cli_args.cpp can reuse it).

create_network_command() now resolves ipv6/veth as CLI flag -> config's own
global.with-ipv6/global.with-veth -> true, so a host that always wants the
tap+relay fallback (or no IPv6) can set it once in the config instead of
passing the flag on every network creation. -w/--write-config fills in both
new keys like the existing six unshare-* bools.
2026-09-05 08:36:12 +00:00
ceamac 1f52bc5f6f Add regression test for the session-straggler sweep; resolve TODO entry
test_session_cleanup.cpp exercises kill_via_cgroup() directly against two
plain forked processes (one setsid()-ing away from the other before it
exits), confirming a reparented straggler is actually reaped -- reproducing
the real escape shape (no pid namespace support at all) through a full
mount/bwrap session isn't possible from the CLI on a single run, since
--unshare-pid is a config-file-only setting, not a flag.

Also resolves TODO.md's SIGINT/SIGTERM entry and extends the relevant
CLAUDE.md sections (bwrap.{h,cpp}, session_cgroup.{h,cpp}, kill_session.{h,cpp})
with the fix's rationale and its known residual limitation (a kernel with
neither cgroup v2 nor pid namespace support still can't be reached
automatically).
2026-09-05 07:20:51 +00:00
ceamac b602de8e7b Document the new Catch2 test suite
README.md: new "Testing" section -- the 4 category/tag-expression table,
what meson test covers vs. what stays manual, and tests/setup-tests.py.

CLAUDE.md: rewrote the self_test.{h,cpp} entry to describe its new role
(pure Catch2 Session::run() plumbing, ENABLE_TESTS-guarded) instead of the
hand-rolled tests it used to contain directly, and added a full
per-file breakdown of the new tests/unit, tests/integration, and
tests/support infrastructure -- including the real bugs found building it
(the two parse_args()/getopt_long state-reset bugs, the ScratchXdgDirs
mixed-iterator UB, the Catch2-inherited-SIGTERM-handler artifact, the
missing /sys mount and spdlog-writes-to-stdout findings), all in the same
narrative depth this file already uses throughout. Also updated the
"Build & test commands" flag list and meson test description.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Gv3s5jckJKzh6JkMoi2Akz
2026-09-04 11:23:24 +00:00
ceamac 5080895043 Document UDP port-forward support
CLAUDE.md's port_forward.{h,cpp} entry, README.md's -p table row, and
docs/networking-design.md's syntax line all updated for the new
[/tcp|udp] suffix. Includes the local dev-machine (root, via the scoped
doas rule) verification detail: TCP unaffected, UDP confirmed end-to-end
(a raw datagram sent to the forwarded host port was read back inside the
container via -x/--exec), same port pair coexisting on both protocols,
invalid-protocol parse errors, clean teardown, and --clean-processes
sweeping both the old 3-field and new 4-field state-file formats. Real
Android iptables/tetherctrl_FORWARD confirmation for UDP is still open.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Gv3s5jckJKzh6JkMoi2Akz
2026-09-04 06:48:20 +00:00
ceamac 0745d30c97 Document the per-session DNS resolution feature
Records the design decision (one dnsmasq instance per session, not per
network -- avoids the NXDOMAIN-fallthrough problem a per-network design
would have hit for multi-network containers) and the three real bugs
found while building it (dnsmasq's --pid-file needing daemonize mode,
its default privilege drop breaking $XDG_STATE_HOME access, and REFUSED
AAAA answers breaking getaddrinfo()-based tools), matching the level of
detail already recorded for the other networking features in this
document and in CLAUDE.md's own file-by-file reference.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Gv3s5jckJKzh6JkMoi2Akz
2026-09-03 17:36:55 +00:00
ceamac e7ef5428d0 Document the -p/--port-forward extern-connectivity fix
Records the root-cause investigation and fix for -p/--port-forward not
reaching a server on an extern network (host root had no route to the
container subnet, and the route alone wasn't consulted without a matching
ip rule -- Android's policy routing has no default "lookup main" rule),
plus the related uplink-rollback-on-failure robustness bug found while
testing it, matching the level of detail already recorded for the other
networking fixes in this document.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Gv3s5jckJKzh6JkMoi2Akz
2026-09-03 12:19:26 +00:00
ceamac 37ab2fcb1e Document the multi-network join race and its fix
Records the strace-based root-cause investigation for the bug where
joining 2+ networks in one -r/--run left every network after the first
permanently unreachable, and the retry-on-EIO/ENETDOWN fix applied in
network_tap_relay.cpp, matching the level of detail already recorded for
the extern-connectivity investigation above it.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Gv3s5jckJKzh6JkMoi2Akz
2026-08-31 17:00:25 +00:00
ceamac 743e899c3d Document extern's private-namespace + uplink architecture
Updates docs/networking-design.md, CLAUDE.md, and README.md to describe
the current, corrected extern network architecture (see the previous
commit) instead of the superseded host-root-bridge design: both extern
and intern now provision their bridge inside a dedicated private
namespace, and extern additionally gets a point-to-point uplink out to
host root, with the three real-device-confirmed pieces (FORWARD insert
ordering, outbound ip rule, return-path ip rule) that make it actually
carry traffic. docs/networking-design.md gets the full incident writeup,
including exactly how each piece was diagnosed on the real device.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Gv3s5jckJKzh6JkMoi2Akz
2026-08-31 12:23:09 +00:00
ceamac bebf559039 Create tap devices persistently via ip tuntap add, drop retry logic
Real-device testing showed the previous retry-based fix (ad30f93) was
insufficient: a bare ioctl(TUNSETIFF)-created tap device (no IFF_PERSIST)
could work for one command and then vanish for the next on that kernel,
not just be slow to appear. Both tap devices are now created ahead of
time via an external `ip tuntap add dev <name> mode tap` before being
attached to via open_tap(), making them genuine persistent netdevices
with no tie to any fd/process lifetime -- the same technique QEMU/libvirt
use. stop_tap_relay() now explicitly `ip link del`s the host-side device
since it no longer disappears on its own; the crash-orphan sweep records
each relay's network kind/name too so it can do the same for orphans.
All retry logic (network_join.cpp's run_with_retry(), self_test.cpp's
wait_for_container_device_visible()) is removed as no longer needed.

self_test.cpp's post-teardown assertions updated to match: the host-side
device is now expected gone after stop_tap_relay(), while the
container-side device is expected to persist (it only goes away once its
own namespace is torn down, not merely because the relay stopped).

Verified end-to-end on the dev machine with --no-veth forcing the
fallback: eth0 stayed visible and usable across repeated commands with
no disappearance, and both gateway and outside (8.8.8.8) ping succeeded
at 0% loss.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Gv3s5jckJKzh6JkMoi2Akz
2026-08-30 19:59:14 +00:00
ceamac ad30f93f77 Retry container-side tap device setup, external process only
A user's log from the real target device showed nsenter'd `ip addr
add ... dev eth0` failing with "Cannot find device" immediately after
network_tap_relay.h's relay had already created it -- confirmed by
hand that retrying the whole session a few times eventually worked.

join_one_network() now retries (bounded, ~500ms, quiet until final
success/give-up) the three steps that touch the just-created container
interface -- IPv4 address, IPv6 address, bringing it up -- via a new
run_with_retry() instead of plain run().

A tempting first fix was investigated and ruled out by direct A/B
testing, not just reasoned about: having the relay itself self-verify
the device is visible (a same-process check, immediately after
creating it, before ever reporting success) was tried first, in
relay_child_main(). It made things categorically worse: the
container-side device became permanently invisible to every external
nsenter afterward, 100% reproducibly (confirmed with a 10-second retry
budget -- never once became visible), on a mechanism that had
otherwise worked correctly and instantly, zero retries needed, on
every real session tested earlier the same day -- including a
from-scratch self-test reproduction that had passed reliably many
times before this one change, and immediately went back to passing
once it was reverted. Root cause not fully understood (something about
forking a subprocess that inherits the tap fd -- deliberately not
O_CLOEXEC -- while still holding it open, immediately after device
creation, appears to corrupt the device's external visibility on this
kernel specifically), but the fix is unambiguous: never add an
internal, same-process/fd-holding self-check to the relay; only the
external, separate-process retry is safe.

network_tap_relay.cpp ends up completely unchanged -- the actual fix
lives entirely in network_join.cpp's own retry. self_test.cpp's own
container-visibility check needed the same external retry treatment,
for the same underlying reason.

Verified as root via the doas rule: three separate real --no-veth
sessions all succeeded getting eth0 on the first attempt (no retries
triggered), and the self-test passes reliably across repeated runs.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Gv3s5jckJKzh6JkMoi2Akz
2026-08-30 19:26:39 +00:00
ceamac cf166ed3b4 Use a genuinely random ULA /48 for auto-allocated IPv6 subnets
The old fd00:168:0::/48 base was never actually generated via RFC
4193's randomization procedure -- just a memorable placeholder chosen
to visibly pair with the IPv4 10.168.x.x scheme. Replaced with
fdf0:f243:f06f::/48, a real randomly-generated ULA prefix.

That /48 consumes all three "identity" hextets a ULA prefix has room
for, leaving only the subnet-id (4th) hextet -- the same one the
per-network auto-allocation index already lived in -- with nowhere
left to also place a fixed "168" marker without colliding with either
the random prefix or the index itself. Per the user's own choice
(offered two options): the per-network index is now offset by a
constant 168 instead of matching IPv4's index number-for-number, so
the first auto-allocated network's IPv6 block is
fdf0:f243:f06f:168::/64 (paired with 10.168.0.0/24), second is
...:169::/64 (paired with 10.168.1.0/24), and so on -- deterministic
and still visibly project-stamped, just via a constant offset instead
of an identical digit.

network_subnet.cpp's new ipv6_ula_prefix48/ipv6_subnet_id_base
constants hold the new prefix and offset.

Verified as root via the doas rule: two freshly created extern
networks got fdf0:f243:f06f:168::/64 and fdf0:f243:f06f:169::/64
exactly as expected, correctly paired with their IPv4 subnets.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Gv3s5jckJKzh6JkMoi2Akz
2026-08-30 18:49:15 +00:00
ceamac 8a0d800478 Drop IPv6 NAT (MASQUERADE): never correct IPv6 practice, unsupported
The real target device's ip6tables build has no MASQUERADE target,
breaking extern network provisioning whenever IPv6 was enabled. Rather
than work around that gap, dropped the ip6tables MASQUERADE rule
entirely, unconditionally, on both the veth and tap+relay paths --
it was never correct IPv6 design to begin with. The fd00::/8 ULA
addresses this project auto-allocates (network_subnet.h) are
non-globally-routable by design (RFC 4193, the IPv6 equivalent of
RFC1918 private space); NAT66 for them isn't how IPv6 is meant to get
outside access -- that's supposed to come from a properly delegated,
globally-routable prefix (DHCPv6-PD), which this project doesn't do.
Dropping NAT66 is the honest design, not a workaround.

extern's IPv6 side now behaves exactly like intern's already did: real
same-bridge reachability between containers, no path to the actual
internet. IPv4 is unaffected -- extern still gets full NAT'd outside
access there. IPv6 forwarding stays enabled (harmless, global,
available for other uses later); only the ip6tables MASQUERADE call
and the ip6tables dependency check that gated it were removed
(network_bridge.{h,cpp}'s provision_bridge()/teardown_network_state()/
check_network_dependencies()) -- one less required tool on the target
device too.

Verified as root via the doas rule: creating and fully deleting an
extern network with IPv6 enabled no longer invokes ip6tables at all.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Gv3s5jckJKzh6JkMoi2Akz
2026-08-30 18:38:57 +00:00
ceamac 745930aad6 Resolve gateway/outside reachability gap: stale test state, not a bug
Retested the tap+relay fallback on a clean host after the user cleared
out accumulated leftover bridges and iptables rules from many earlier
rounds of manual testing (left behind because --delete-network never
tore down live host state before --delete-network-full existed).

With a clean host: a fresh --no-veth extern network's gateway IP and a
real external host both answered ICMP with 0% packet loss, and a raw
TCP connect (nc) to an external host completed cleanly. A separate
wget segfault against the same host was confirmed to be an unrelated
busybox bug (reproduces identically regardless of join mechanism), not
a networking issue. Inter-container connectivity was reconfirmed
working at the same time.

This closes out the previously-reported "gateway/outside reachability
unconfirmed" gap in docs/networking-design.md and CLAUDE.md -- both
peer-to-peer and gateway/outside connectivity through the tap+relay
fallback are now confirmed working on this dev machine.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Gv3s5jckJKzh6JkMoi2Akz
2026-08-30 18:31:21 +00:00
ceamac 534136339f Add --delete-network-full to fully tear down a network's live state
--delete-network only ever removed the config entry, leaving the
bridge/iptables/persistent-namespace state behind. Since
ensure_network_provisioned() treats "bridge exists" as "already fully
provisioned" and skips re-adding anything, a network recreated with
the same name after a plain --delete-network silently never got a
fresh MASQUERADE rule if the old one had been removed separately by
hand -- the bridge itself was still there the whole time.

teardown_network_state() (network_bridge.{h,cpp}) is the reverse of
ensure_network_provisioned(): for extern, removes the MASQUERADE
rule(s) then deletes the bridge; for intern, removes the whole
persistent namespace in one step (destroys the bridge inside it too,
no separate ip link del needed). Deliberately leaves the IPv4/IPv6
forwarding sysctls alone -- those are global host state shared across
every extern network, not per-network. Each step is best-effort
(teardown_step(), logging a warning not an error on failure) since a
step "failing" because that piece was already gone by hand is the
expected case this exists to handle, not a reason to abort --
delete_network_command() doesn't gate the config removal on any of
this succeeding, unlike delete_volume_command()'s own -full variant.

--delete-network-full wired into cli_args.{h,cpp} the same way
--delete-volume-full is.

Verified as root via the doas rule: an extern network's bridge and
MASQUERADE rule were both confirmed gone after --delete-network-full,
and recreating a network with the same name went through
provision_bridge() fresh instead of short-circuiting on a stale
bridge_exists() check -- fixing exactly the gap reported (a manually
removed MASQUERADE rule never came back on delete+recreate). An intern
network's persistent namespace was likewise confirmed fully removed
and recreatable without conflict.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Gv3s5jckJKzh6JkMoi2Akz
2026-08-30 17:59:52 +00:00
ceamac 69a18924b4 Add bridge name column to --list-networks
list_networks_command() now includes each network's bridge name
(recomputed via bridge_name(), not stored -- it's already a pure
deterministic function of the network name), tab-aligned the same way
as the existing name/kind/subnet columns, positioned before the
trailing unaligned IPv6 column. Useful for correlating a network entry
with its live host-side state (`ip link show <bridge>`,
`iptables -t nat -L`) without recomputing the hash by hand.

Verified as root via the doas rule against a fresh extern and intern
network.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Gv3s5jckJKzh6JkMoi2Akz
2026-08-30 17:15:31 +00:00
ceamac fd234124e1 Add crash-orphan sweep for stale tap-relay processes
Direct tap+relay analog of the existing -p port-forward sweep: unlike
a veth pair or a session's own bridge/persistent-namespace state, a
relay process is host-global state with no automatic teardown if
slocker-lite crashes before reaching its own stop_tap_relay() calls
(bwrap still dies immediately via --die-with-parent, so only the relay
can actually leak).

tap_relay_state_path() uses the same xdg_state_dir()/
sanitize_for_filename() naming scheme as session_pid_file_path()/
port_forward_state_path(), so clean_stale_tap_relays() can
cross-reference filenames against list_sessions() the same way
clean_stale_port_forwards() already does. record_tap_relays()/
remove_tap_relay_record() are wired into run_container() the same
two-places-split as their port-forward counterparts. Wired into
clean_processes_command() (--clean-processes) alongside the two
existing sweeps.

Verified via a controlled scratch test, the same shape the original
port-forward sweep used: a plain rootless daemonized session (no
network join needed for the sweep logic itself) gave a real, live pid,
alongside a hand-written matching record and a fabricated stale one in
the same rootless state dir -- the matching record was left untouched,
the fabricated one was correctly identified as stale and removed
(kill() on its nonexistent pid failing harmlessly with ESRCH), and
killing the real session then correctly swept its own now-stale record
on a second run.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Gv3s5jckJKzh6JkMoi2Akz
2026-08-30 16:35:26 +00:00
ceamac f323dab3da Wire tap+relay fallback into join_one_network()
join_one_network() now branches on should_use_veth(network)
(network_bridge.h): the existing veth-pair path when the kernel
supports veth and the network wasn't created with --no-veth, or
create_tap_relay() (network_tap_relay.h) otherwise -- both produce the
same postcondition (a ready eth<N> in the container's namespace)
before the unchanged IP-assignment/route code runs. JoinedNetwork
gains an optional `relay` field; run_container() (commands.cpp)
collects these into active_relays (mirroring active_port_forwards) and
calls stop_tap_relay() for each after run_bwrap() returns.

Two real bugs caught by testing while verifying this end-to-end:

1. The relay child, unlike every other forked child in this project,
   never exec()s, so O_CLOEXEC on fds created before its fork (like
   daemonize.cpp's own report pipe) never takes effect -- it only
   closes fds across exec(), not across a fork that never execs. The
   relay inherited a live copy of that pipe's write end and kept it
   open forever, so `-D` combined with `-n <no-veth network>` hung
   indefinitely (the daemonize handshake's read-until-EOF never saw
   EOF). Fixed with close_inherited_fds(), scanning /proc/self/fd and
   closing everything except stdio and the relay's own report pipe, as
   the first thing relay_child_main() does.

2. A first-attempt companion fix -- adding the relay's pid to the
   session's own cgroup so --kill would reach it directly -- was tried
   and reverted: remove_session_cgroup() runs inside run_bwrap(),
   before run_container() gets to call stop_tap_relay(), so the cgroup
   was still non-empty at removal time and every such session left a
   stray cgroup directory behind (EBUSY, confirmed by testing). The
   ordinary flow already stops the relay correctly (killing bwrap lets
   run_container() reach its own cleanup), so this wasn't worth the
   added complexity.

Verified end-to-end as root via the doas rule, using a --no-veth
extern network on this dev machine specifically to exercise the
fallback: two containers joined the same network, got distinct
addresses via two tap devices + relays (no veth at all), and pinged
each other with 0% packet loss, repeatably.

Known gap, confirmed by testing, not yet root-caused: neither
container could reach the network's own gateway IP (ICMP or TCP),
despite ARP resolving correctly -- ruling out an L2/relay framing
problem. The identical bridge/subnet/host reached via veth instead
works perfectly, ruling out every environment-level explanation that
would affect both paths equally. rp_filter=0 (host-tap, bridge, and
`all` scope) was tried and confirmed not to fix it. Diagnosing further
needs host tools (tcpdump, direct iptables/sysctl inspection) this
session's doas access doesn't permit. Peer-to-peer connectivity (an
intern network's whole purpose) is solid; gateway/outside reachability
through this fallback needs re-verification, ideally on the actual
veth-less target device, before being relied on.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Gv3s5jckJKzh6JkMoi2Akz
2026-08-30 16:31:27 +00:00
ceamac 96efcf37e1 Add network_tap_relay: tap-backed veth substitute, standalone
Second step of the tap+relay fallback for veth-less kernels (the real
target device supports tun/tap but not veth). Reuses the existing
bridge as the switching fabric -- provision_bridge()'s NAT/forwarding
setup needs no changes -- and only replaces how a container's
namespace gets connected to it:

- a host-side tap device, created wherever the network's bridge lives
  and enslaved to it, playing veth's host-side role
- a container-side tap device, created directly inside the container's
  namespace and named eth<N> from the start (no rename step needed)
- a relay process holding both fds open, copying raw Ethernet frames
  bidirectionally between them -- reproducing a veth pair's kernel
  wire via one userspace hop

Not wired into join_one_network() yet -- this commit only adds
create_tap_relay()/stop_tap_relay() and exercises them standalone via
a new self-test (throwaway bridge + throwaway namespace).

A real synchronization bug turned up while writing that self-test:
fork() returning to the parent doesn't mean the child has reached its
own unshare(CLONE_NEWNET) yet, so using its pid immediately raced and
created the container-side tap in the wrong (host) namespace. Fixed
by polling namespace_isolated() first, the same guard
network_join.cpp's wait_for_isolated_net_namespace() already uses for
a real session.

Verified twice as root via the doas rule: host-side tap gets created
and attached to the bridge, container-side tap gets created with the
right name inside the target namespace, and -- the biggest open
assumption from the design doc addendum -- both devices disappear on
their own once stop_tap_relay() stops the process, no explicit
`ip link del` needed.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Gv3s5jckJKzh6JkMoi2Akz
2026-08-30 16:06:32 +00:00
ceamac 08895297a9 Add veth capability probe + --no-veth network flag
Prep work for a tap+userspace-relay fallback: the real target device
supports tun/tap but not veth (CONFIG_VETH stripped from its kernel),
so -n/--network joins there can't use the veth-pair mechanism as-is.

probe_veth_support() (network_bridge.{h,cpp}) detects kernel veth
support the same way bwrap.cpp's kernel_supports_namespace() probes
namespace types: fork, unshare(CLONE_NEWNET) into a throwaway
namespace, try `ip link add ... type veth ...` there. should_use_veth()
combines that with a new per-network NetworkEntry::veth policy flag
(default true, config_file.h), mirroring how namespace_policy_enabled()
already combines kernel capability with policy for --unshare-xxx.

--no-veth at network-creation time (-n <name> --extern|--intern
--no-veth) sets veth: false, forcing the not-yet-built tap+relay
fallback even on a veth-capable kernel like this dev machine -- lets
that path be exercised here without the actual veth-less hardware.

Verified as root via the doas rule: probe_veth_support() returns true
on this dev machine (a real veth pair is created successfully), and
--no-veth correctly persists veth: false while should_use_veth() still
returns false regardless of kernel support.

The fallback itself (network_tap_relay.{h,cpp}) isn't wired in yet --
a --no-veth network simply has no way to join a container until that
lands.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Gv3s5jckJKzh6JkMoi2Akz
2026-08-30 15:59:40 +00:00
ceamac a9cd3bf643 Fix -x/--exec to also join a session's network namespace
net was deliberately excluded from exec_session.cpp's joinable_namespaces
list, written back when this project never isolated networking at
all. Now that -r/--run sometimes does (whenever -n/--network was
used), -x/--exec'ing into such a session saw the host's own network
stack instead of the container's -- confirmed directly: it showed the
host's unrelated listening ports and couldn't reach the container's
own service on 127.0.0.1.

Fixed by joining net the same way -x/--exec already joins
mnt/uts/ipc/pid/cgroup/user when they differ from the caller's own --
not required, so a session with no isolated net namespace (never
joined any network) is unaffected, the entry is just skipped like any
other identical-to-ours namespace.

Verified as root (via a scoped doas rule): execing into a session
joined to an extern network now correctly shows its own eth0 and
reaches its own service on 127.0.0.1; execing into a plain session
with no -n is unaffected.
2026-08-30 13:39:25 +00:00
ceamac 7605831269 Add crash-orphan sweep for stale -p port-forward rules
Commit 6/6 (final) of the network isolation feature
(docs/networking-design.md). Landed narrower in scope than originally
planned once the actual orphan surface was worked out: veths need no
sweep at all (the kernel tears down an entire pair once either end's
namespace is destroyed, so nothing survives a crash), and bridges/
persistent namespaces are deliberately meant to always outlive any one
session (the whole point of the reboot-reconciliation design already
built in commit 3). Only -p's iptables rules are host-global state
with no automatic teardown, so that's the entire sweep.

port_forward.{h,cpp}: record_port_forwards()/remove_port_forward_record()
persist a session's active mappings to $XDG_STATE_HOME/slocker-lite/
port-forwards/<container_name>-<pid> -- the exact same naming scheme
as session_pid_file_path() (pid_file.h), so clean_stale_port_forwards()
can cross-reference filenames directly against list_sessions()'s own
liveness check rather than re-deriving it. --clean-processes
(commands.cpp) now also runs this sweep alongside its existing
stale-pid-file one.

Also fixed a real gap in commands.cpp caught while wiring this up:
on_bwrap_pid_known was only set when daemonize_flag ||
!network_specs.empty(), so a bare "-p ... " with no -n or -D would
silently never even attempt to run -- no error, nothing logged, the
whole flag just quietly did nothing.

Verified via a controlled scratch test rather than a literal kill -9
on a root-owned slocker-lite process (not achievable through this
session's scoped doas rule, which only permits running slocker-lite
itself): a fabricated stale port-forward record was correctly
detected, its rule-removal attempted, and its file cleaned up, while a
record matching a real running session was left completely untouched.
2026-08-30 13:33:47 +00:00
ceamac 5c87cac430 Add -p/--port-forward: iptables DNAT into extern-joined containers
Commit 5/6 of the network isolation feature (docs/networking-design.md).
port_forward.{h,cpp}: parse_port_forward_spec() parses
"[<network>:]<host-port>:<container-port>"; add_port_forward()
resolves the network (by name, or the container's sole extern network)
against join_networks()'s result and adds the DNAT/FORWARD rules;
remove_port_forward() undoes them. join_networks() (network_join.{h,cpp})
now returns the joined networks with their assigned IPs (was a bare
bool) so port-forward setup knows where to send traffic. -p requires
-r, is repeatable, network names may no longer contain ':' (needed to
keep the spec syntax unambiguous -- is_valid_network_name(),
network_subnet.h).

Two real corrections from testing, not assumed:
- The DNAT rule needs both nat PREROUTING and nat OUTPUT -- PREROUTING
  never sees locally-generated packets (e.g. curl run on the same
  host), only OUTPUT does. PREROUTING-only left the host's own real IP
  connection-refused despite the container being directly reachable.
- curl localhost:<port> still doesn't work even with both chains --
  a separate problem, NAT hairpinning: the container sees an inbound
  packet claiming a loopback source arriving on a non-loopback
  interface and drops it as martian. A net.ipv4.conf.*.route_localnet
  sysctl was tried and confirmed not to fix this alone, then removed
  rather than left in as dead code. Not solved here (would need scoped
  source masquerading or a userland proxy); curl <host's real IP> is
  the actually-relevant, verified-working path for real clients.

Also surfaced (unrelated to -p, found while testing it, not fixed
here): -x/--exec doesn't join the net namespace -- written when this
project never isolated networking at all -- so it currently sees the
host's own network stack instead of a network-isolated session's own.

Verified end-to-end as root (via a scoped doas rule): a container
serving HTTP on an extern network with -p 8080:80 was reachable via
curl <host's real IP>:8080; the rule was confirmed gone after the
session was killed.
2026-08-30 13:28:23 +00:00
ceamac 8cc967e748 Join -r/--run containers to networks: veth creation, IPs, routes
Commit 4/6 of the network isolation feature (docs/networking-design.md).
network_join.{h,cpp}: join_networks() waits (bounded, polling) for the
session's own isolated net namespace to exist -- bwrap's outer pid
never enters it, and the on_bwrap_pid_known callback fires before
bwrap has even started its own setup -- then per network: ensures it's
provisioned, creates a veth pair where the bridge lives, attaches the
bridge side, moves the container side into the session's namespace as
eth<N>, assigns it a free address, brings it up, and (extern only)
replaces the default route.

sandbox_process.{h,cpp}: generalized pid_namespace_isolated() into
namespace_isolated(outer_pid, ns_pid, ns_type) so this can reuse it for
"net" instead of "pid".

network_subnet.{h,cpp}: gateway-address logic generalized into
host_address(af, cidr, n) shared by the existing gateway functions
(n=1) and new ipv4/ipv6_host_address() (n=2, 3, ... for containers).

network_bridge.{h,cpp}: bridge_name()/wrap_for_network() exported so
network_join.cpp can attach to the exact bridge/namespace
network_bridge.cpp provisioned.

commands.cpp: run_container() validates network namespace isolation is
actually available before ever starting bwrap (can't be degraded the
way --hostname is), then joins networks from on_bwrap_pid_known,
before the -D/--daemonize report is sent.

Real bug caught by testing, fixed before landing: address allocation
first tried to detect in-use IPs via `ip addr show master <bridge>`,
but a container's address lives on its own interface inside its own
private namespace, invisible from the bridge's namespace -- two
concurrent containers on the same network both got 10.168.0.2. Fixed
with a flock-based per-address lease file (same technique pid_file.h's
SessionLock already uses), verified with two containers running
simultaneously getting distinct addresses.

Known, documented limitation: a very short-lived sandboxed command can
exit before the namespace-wait polling catches up (bwrap execs
straight into the target with no hook point in between namespace
creation and exec); real long-running networked services are
unaffected.

Verified end-to-end as root (via a scoped doas rule): two containers
on the same intern network got distinct addresses and could ping each
other; an intern-joined container could not reach the outside; an
extern-joined container reached the real internet through NAT; a
container joining both simultaneously got two working interfaces.
2026-08-30 13:11:28 +00:00
ceamac 24b8ddcce7 Add bridge provisioning for networks (root-only)
Commit 3/6 of the network isolation feature (docs/networking-design.md).
network_bridge.{h,cpp}: ensure_network_provisioned() stands up a
network's real bridge -- idempotent (checks `ip link show` first), so
this doubles as the reboot-reconciliation mechanism, no separate code
path. extern's bridge lives in the host's own root namespace with
net.ipv4.ip_forward + an iptables MASQUERADE rule for the subnet (+
IPv6 equivalents if enabled); intern's bridge lives inside its own
dedicated persistent namespace (persistent_netns.h) with no forwarding
or NAT at all -- a structural isolation boundary, not just a missing
rule. Bridge names are a deterministic FNV-1a hash of the network name
(not std::hash, whose value isn't guaranteed stable across a rebuild),
kept under Linux's 15-char interface name limit.

network_subnet.{h,cpp} gains ipv4_gateway_address()/
ipv6_gateway_address() (mask a CIDR to its network address, +1 for the
bridge's own ".1"). create_network_command() now calls
ensure_network_provisioned() before persisting the config entry -- a
network that fails to provision isn't saved.

Verified end-to-end as root (via a scoped doas rule): a real extern
network's bridge/gateway IPs/forwarding/NAT rule, and a real intern
network's isolated bridge with neither, both came up correctly; test
networks removed via --delete-network afterward.
2026-08-30 12:50:55 +00:00
ceamac db3a9d82c7 Add persistent network namespace primitives
Commit 2/6 of the network isolation feature (docs/networking-design.md).
persistent_netns.{h,cpp}: create/verify/remove a network namespace kept
alive with no process in it, the way `ip netns add` does (fork a child,
unshare(CLONE_NEWNET), bind-mount its /proc/self/ns/net onto a
persistent path, exit -- the bind mount keeps it alive). Root-only
(CAP_SYS_ADMIN for the bind mount), best-effort like this project's
other host-state primitives. Not wired into -n/--network yet.

xdg_state_dir() (pid_file.cpp) moved out of its anonymous namespace so
this file can reuse the same $XDG_STATE_HOME resolution rather than a
second, drifting copy.

-t/--test now exercises the create/verify/remove cycle (skipped with a
message, not a failure, when not root) -- confirmed working via doas.
2026-08-30 12:43:12 +00:00
ceamac ec09b96b56 Add -n/--network config CRUD: schema, subnet/IPv6 allocation, CLI
Commit 1/6 of the network isolation feature (docs/networking-design.md):
config-only, no host-side effects yet. Adds NetworkEntry {name, kind,
subnet, ipv6, subnet6} and a networks config-file section parallel to
volumes; network_subnet.{h,cpp} for CIDR validation, overlap checking,
and auto-allocation (10.168.<n>.0/24 / fd00:168:0:<n>::/64, paired,
--subnet/--subnet6 overrides); -n/--network create/list/delete CLI,
dual-purpose like -v/--volume (alone creates, repeatable with -r to
join -- joining isn't wired up yet, just accepted).

-n was already taken by --no-nsenter; moved that to long-option-only
(--no-nsenter), matching --kill's "rare flag, no real loss" precedent,
since --network will be far more heavily used.
2026-08-30 12:39:28 +00:00
ceamac ace71e0474 Add -w/--write-config to bootstrap a fully-populated config file
Writes every supported config option explicitly -- the six
unshare-* bools defaulted via value_or(true), log-level captured
from the actually active spdlog level (so an explicit --log-level
passed alongside -w is persisted too) -- creating the file and its
parent directory if missing, and prints its full path. Existing
values (including volumes) are preserved untouched.

Also fixes a stale README row left over from unplugging the
namespace probe out of -t/--test.
2026-08-30 09:44:03 +00:00
ceamac bcae8bbcd4 Unplug the bwrap namespace-support probe from -t/--test
detect_bwrap_unshare_args()'s output was diagnostic/capability info,
not an actual test; run_self_tests() reverts to an empty placeholder
for real tests to land in later.
2026-08-30 09:23:55 +00:00
ceamac c70abb56a9 Make bwrap's --unshare-xxx namespaces configurable via global.unshare-*
Adds six global.unshare-{user,ipc,pid,net,uts,cgroup} config-file keys
(1/on/yes/true or 0/off/no/false, case-insensitive, default on) that
gate whether -r/--run requests each bwrap --unshare-xxx flag when the
kernel also supports it. Replaces the previous hardcoded skip of
--unshare-net, which is now policy-driven like the other five types
and defaults to enabled -- preparation for real network namespace
isolation (slirp4netns) next, on this same branch.
2026-08-30 09:15:39 +00:00
ceamac 33cd97fdc8 Make --kill long-option-only, no -k short form
Per the user's request: --kill is destructive enough (stops every process
a session started) that typo-prone brevity isn't worth it -- dropping the
short option makes it harder to invoke by mistake.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Gv3s5jckJKzh6JkMoi2Akz
2026-08-29 10:05:23 +00:00
ceamac 28332ac5c2 Change -e/--exec's short option to -x
-e was going to collide with the shape of other single-letter destructive-
ish operational flags; -x frees up the letter and reads fine as
--exec's short form.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Gv3s5jckJKzh6JkMoi2Akz
2026-08-29 10:02:31 +00:00
ceamac 8c4afb82e8 Add -k/--kill <pid> to fully stop a running session
A plain `kill <tracked_bwrap_pid>` doesn't kill everything a container
started: on a kernel without pid namespace support, a service that
daemonizes (double-forks and detaches) before the entrypoint execs into its
main command reparents all the way to the *host's* own pid 1, completely
disconnected from the sandboxed session -- confirmed via a real session log
from the user's own Android target device, where php-fpm and caddy both
kept running as orphans after killing the tracked pid.

kill_session() (src/kill_session.{h,cpp}) picks between three
independently-named strategies per session, based on what's actually
available for it:
- kill_via_cgroup(): preferred when the session has a dedicated cgroup
  (src/session_cgroup.{h,cpp}, set up at -r/--run time in run_bwrap()'s
  on_start callback). Reaches every process the session ever started,
  daemonized/reparented or not, regardless of pid namespace support.
- kill_via_pid_namespace(): used when --unshare-pid was genuinely in effect
  for the session (src/sandbox_process.{h,cpp}, shared with exec_session.cpp,
  which already needed resolve_namespace_pid()). Relies on the kernel's own
  guarantee that killing a pid namespace's pid 1 tears down everything in it.
- kill_via_tracked_pid(): fallback, signals the tracked pid directly -- no
  worse than today's manual kill. This is what the user's real target
  device currently falls back to (no pid namespace support there).

Each strategy sends SIGTERM, waits up to a 10s grace period, then forces a
SIGKILL. Verified locally (rootless dev machine, which does support pid
namespaces): a daemonizing test session was fully cleaned up via
kill_via_pid_namespace(), including the forced-SIGKILL escalation path,
with no leftover processes, mounts, or layers.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Gv3s5jckJKzh6JkMoi2Akz
2026-08-29 09:43:12 +00:00
ceamac 247e61d9d8 Add --user/--group support to -e/--exec, matching -r/--run
Previously -e/--exec always ran its command as the host's own invoking
credentials, ignoring whatever uid/gid the session's own -r/--run resolved
it to. Now it defaults to whatever the session's sandboxed command is
already running as (read from /proc/<pid>/status), and --user/--group can
override that, resolved against the session's own /etc/passwd/group
(fetched via nsenter, since the mount namespace isn't otherwise reachable).
Either way it's applied by reusing the already bind-mounted
slocker-lite-priv-drop helper from the original -r/--run, not a second copy.

Refactored resolve_user_and_group() (user_spec.{h,cpp}) to take passwd/group
*content* instead of a filesystem path, so both callers -- run_container()
(local file read) and exec_in_session() (nsenter + cat) -- can share it.
Exported priv_drop::path/helper_name and find_priv_drop_helper() from
bwrap.h so exec_session.cpp can reuse the same helper.

Caught and fixed a second bug during testing on a rootless dev machine:
under -r/--run's own --unshare-user, "root inside the container" is a uid
mapping, not a real privilege drop, so /proc/<pid>/status's uid/gid (read
from outside that namespace) is the host-mapped id, not the container's
own view -- defaulting to a priv-drop there was wrong and failed outright.
Fixed by skipping the default-identity lookup whenever --exec is already
joining a differing user namespace, since nsenter --preserve-credentials
alone already reproduces the container's view via that same kernel mapping.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Gv3s5jckJKzh6JkMoi2Akz
2026-08-29 08:05:55 +00:00
ceamac 1c186b0365 Fix -e/--exec namespace resolution on kernels without CONFIG_CHECKPOINT_RESTORE
/proc/<pid>/task/<pid>/children doesn't exist on every kernel (confirmed
missing on a real Android target), so resolve_namespace_pid() fell back to
the outer bwrap pid itself and nsenter ended up with no namespace flags at
all. Add a portable fallback that scans /proc/<n>/stat for the child whose
ppid matches, the same information pstree uses to build its tree.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Gv3s5jckJKzh6JkMoi2Akz
2026-08-29 07:42:02 +00:00
ceamac fa0bf13732 Fix volume init to always reconcile the host directory's own attributes
resolve_volume_mount() was supposed to initialize a fresh host directory
from the image's own content at the mounted container path, but only ever
did anything when that image-side directory was non-empty. Two bugs
followed: an image declaring an *empty* directory with specific ownership/
permissions (e.g. a data directory owned by a non-root uid/gid) got a host
directory with plain create_directories() defaults instead, and even the
non-empty case never reconciled the directory's own attributes -- only
each copied entry's.

Fixed by splitting into two independent steps in the embedded cp script:
copy contents only when non-empty (as before), then always reconcile the
host directory's own mode/ownership/timestamps/xattrs via
`cp -a --attributes-only -T`. -T/--no-target-directory turned out to be
required -- caught by direct testing: without it, cp nests the image
directory *into* the already-existing host directory instead of
reconciling its attributes, which silently produced a spurious nested
copy and left the host directory's own attributes untouched.

Verified end-to-end against images/gitea.tar's real declared
/etc/gitea and /var/lib/gitea volumes under a real rootless mount: the
resulting host directories' mode/ownership now match the image's own
declared values, with no leftover mounts/layers afterward.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Gv3s5jckJKzh6JkMoi2Akz
2026-08-24 15:10:23 +00:00
ceamac 0f43a02bd7 Split main.cpp into cli_args, commands, and self_test
main.cpp had grown to ~910 lines holding CLI parsing, every command
implementation, and the -t/--test handler all in one file. Split it:

- cli_args.{h,cpp}: getopt_long parsing and all post-loop validation
  (parse_args()), producing a ParsedArgs the rest of the program consumes.
- commands.{h,cpp}: every command implementation plus dispatch_command(),
  an exhaustive switch over Mode with no default -- so -Wswitch (this
  project's warning_level=3) now catches a future Mode value added without
  a matching dispatch case, instead of silently falling through. Confirmed
  by temporarily adding an unhandled enumerator and observing the warning.
- self_test.{h,cpp}: -t/--test's own file, ahead of real tests landing here.

Also fixes Mode::mount, which previously had no explicit dispatch check at
all -- it ran only because it was whatever fell off the end of main()'s
if/else chain when nothing else matched. It's now mount_command(), a real
case in dispatch_command() like every other mode.

main.cpp itself shrinks to ~30 lines: load config, apply its log level,
parse_args(), dispatch_command().

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Gv3s5jckJKzh6JkMoi2Akz
2026-08-24 14:07:57 +00:00
ceamac 00cb04ff41 Document global-state audit and fork-per-container decision
Ahead of docker-compose multi-container support, audited the three pieces
of mutable global state (g_mount_program, g_foreground_child_pid,
g_report_fd/g_log_path) for concurrency safety. Decided each container's
session will run in its own forked OS process, the same model
-D/--daemonize already uses, rather than one process managing multiple
containers without forking. Under that model none of the globals need to
change, since "one OS process" already equals "one running container" --
recorded as a load-bearing constraint for the compose orchestrator.

No code changes; documentation only.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Gv3s5jckJKzh6JkMoi2Akz
2026-08-24 13:17:40 +00:00
ceamac 61f542080d Rename k-prefixed constants to snake_case, grouped in namespaces
Drop the k Hungarian-notation prefix throughout src/. Enum class values
(Mode::, OciPortProtocol::) are already qualified by the enum's own name,
so plain snake_case enumerators are enough. Free-standing constants also
move to snake_case; related ones are grouped under a named namespace
instead of relying on a shared prefix (main.cpp's getopt long-option
codes -> namespace options, bwrap.cpp's priv-drop path/binary name ->
namespace priv_drop). kMountProgram, which was actually mutable global
state rather than a true constant, is renamed to g_mount_program to
match this codebase's existing g_ convention for that kind of state.
Also dedupes the three identical kTabWidth local constants in main.cpp
into one shared tab_width.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Gv3s5jckJKzh6JkMoi2Akz
2026-08-24 12:59:26 +00:00
ceamac f904d33a11 Add -D/--daemonize to run -r/--run sessions in the background
Single-fork daemonize: the child calls setsid() itself rather than
re-enabling bwrap's own --new-session, which was previously removed
(and stays that way) because it only detaches the deeply-nested
sandboxed command, leaving bwrap/nsenter/slocker-lite itself still
attached to the original session -- not real daemonization. Calling
setsid() in slocker-lite's own forked child, before it execs into
nsenter/bwrap, detaches the whole chain at once, since exec() never
changes session membership -- confirmed via ps -o sid,pgid,tty against
a running daemonized session.

The child also ignores SIGHUP (confirmed to survive exec() into bwrap,
unlike a real handler, which exec() resets) and redirects stdin to
/dev/null and stdout/stderr to a log file under
$XDG_STATE_HOME/slocker-lite/logs/ (session_log_file_path(), new
sibling to the existing session_pid_file_path() in pid_file.{h,cpp}).
The original process blocks briefly on a pipe until the child reports
the real bwrap pid (or exits without doing so), then prints it and
exits -- keeping "pid" meaning the same thing everywhere in this
codebase (the same one --list-processes/-e/--exec already use), rather
than introducing a separate daemon-supervisor pid. run_bwrap() gained
an on_bwrap_pid_known callback (bwrap.{h,cpp}) for this, invoked
alongside the existing session-lock creation at the same instant.

The daemonized child is what runs run_container()'s entire existing
body afterward, including the unmount/cleanup that already ran once
bwrap exits -- no separate watcher/reaper process.

Testing caught a real bug before this was correct: the log file gets
renamed from its initial (daemon-pid-named) filename to the final
<container_name>-<bwrap-pid>.log once the real pid is known, but the
parent had already been told the pre-rename path and was never updated
-- fixed by re-reporting the path over the same pipe after the rename.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Gv3s5jckJKzh6JkMoi2Akz
2026-08-23 16:41:07 +00:00
ceamac e7dac86eee Add --env/--env-file to set environment variables under -r/--run
Both flags are repeatable and share a single ordered EnvSpec list
(env_spec.{h,cpp}) so a later --env or --env-file always overrides an
earlier one for the same name, regardless of which flag set it.
--env-file reads one VAR=VALUE per line, skipping blank lines and
#-comments. resolve_env_specs()'s result is appended after
build_sandbox_env()'s own PATH/HOME/PWD/TERM defaults, letting an
explicit --env override any of them too.

Testing this surfaced a real bug in the environment-at-exec-time
mechanism from the previous change (dropping bwrap's own --clearenv):
since bwrap/nsenter are now exec'd with the same explicitly-built
environment the sandbox sees, a --env PATH=... override broke
execvp()'s ability to even locate bwrap/nsenter themselves (bare-name
PATH lookup happens in the child, using the already-overridden PATH).
Fixed by resolving both to absolute paths via find_in_path(), called
from this process's own unmodified environment before fork() --
confirmed by testing that only the sandboxed command's own lookup is
now affected by a PATH override, not bwrap/nsenter.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Gv3s5jckJKzh6JkMoi2Akz
2026-08-23 15:12:22 +00:00
ceamac bec5456c33 Drop --clearenv; control the sandbox's environment at exec time
Moves responsibility for the sandboxed command's environment out of
bwrap's own --clearenv/--setenv flags and into the process-launching
code itself: build_sandbox_env() (bwrap.cpp) constructs the exact
environment (PATH, HOME, PWD, TERM if present), and run_bwrap() passes
it to run_process_foreground()'s new optional env override, which
replaces the forked child's entire environment via clearenv()/setenv()
(plain POSIX, not the GNU-only execvpe(), since the target platform
includes musl) right before exec. bwrap, nsenter (when interposed),
and slocker-lite-priv-drop all just forward whatever environment
they're launched with, so controlling it once at the outermost exec
is sufficient.

Also adds PWD=/ to the constructed environment: per bwrap's own man
page, --clearenv never actually unset PWD in the first place (bwrap
manages it separately, alongside --chdir), so the old --clearenv/
--setenv sequence was leaving it unset by omission rather than by
choice. Hardcoded to "/" to match --chdir's own value.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Gv3s5jckJKzh6JkMoi2Akz
2026-08-23 14:56:11 +00:00
ceamac 00482b6b42 Add -e/--exec to join a running -r/--run session
Validates the given pid against the same tracked-session liveness
check --list-processes/--clean-processes already use, then joins its
namespaces via nsenter and runs a command there in the foreground.

Two things discovered only by testing against a live session, not
assumed up front:

- The tracked pid is bwrap's own outer process. It sets up the
  mount/user namespaces itself, then clone()s the actual sandboxed
  command into fresh pid/uts/ipc/cgroup namespaces -- clone()'s
  namespace flags only ever affect the new child, never the caller,
  so the outer process itself never enters those namespaces at all.
  exec_in_session() resolves that real child via
  /proc/<pid>/task/<pid>/children and joins its namespaces instead,
  falling back to the outer pid if that can't be read.

- Rather than nsenter -a (which would hit a known "Invalid argument"
  failure re-entering an identical namespace -- this project already
  worked around exactly that once, for the containers-storage mount
  path), each namespace type is only joined if
  /proc/<pid>/ns/<type> actually differs from this process's own.
  nsenter also needs --preserve-credentials, or it tries to
  setuid/setgid/setgroups to the target's identity, which fails
  outright against the setgroups-denied unprivileged user namespace
  bwrap creates whenever -r/--run isn't root.

Verified end-to-end: joined shell gets the container's own hostname,
process tree (ps shows only container processes), and root
filesystem; untracked/stale pids error out cleanly without touching
nsenter; Ctrl-C during the joined command doesn't disturb the
original session; no leftover mounts after either exits.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Gv3s5jckJKzh6JkMoi2Akz
2026-08-22 09:41:32 +00:00
ceamac d4c0e8f0a1 Add --clean-processes to remove stale session pid files
Scans the same $XDG_STATE_HOME/slocker-lite/run/ directory as
--list-processes and removes every pid file that's genuinely stale.
The liveness check and the removal happen atomically per file (the
same non-blocking flock() used to test it is held across the
remove() call itself), rather than reusing a separate earlier scan,
closing the race window where a new session could start in between.
Only files actually removed are reported, one line each; sessions
still running are left untouched and silently skipped.

Refactored list_sessions() and the new clean_stale_sessions() to
share a private open_session_file() helper for the open/read-pid/
recover-name step they both need.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Gv3s5jckJKzh6JkMoi2Akz
2026-08-22 09:16:57 +00:00
ceamac 8c55e5c288 Add --list-processes to list running -r/--run sessions
Lists every session pid file found under
$XDG_STATE_HOME/slocker-lite/run/, showing pid, container name, and
status (running or exited). Status is determined the same way any
external tool could check it: a non-blocking exclusive flock() on the
file that succeeds means it's actually stale (nothing holds it), so
the session is reported as exited in that case; the lock is always
released again immediately, never left held by the check itself.

list_sessions() (pid_file.{h,cpp}) reads the real pid from each file's
own contents rather than parsing it out of the filename, which would
be ambiguous for container names that themselves contain '-'.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Gv3s5jckJKzh6JkMoi2Akz
2026-08-22 09:05:27 +00:00
ceamac 23f380e180 Track running -r/--run sessions with a locked PID file
Each bwrap session is now recorded under
$XDG_STATE_HOME/slocker-lite/run/<container-name>-<pid> (falling back
to $HOME/.local/state/...), holding an exclusive advisory flock() for
as long as it's running -- so any tool can tell a stale leftover file
apart from a live session by attempting the same non-blocking flock().
The file is removed once the run ends, on every exit path including a
forwarded Ctrl-C.

run_process_foreground() gained an optional on_start(pid) callback,
fired right after fork() succeeds -- the only point the real bwrap pid
is knowable, since exec() (including nsenter handing off to bwrap)
never changes it. run_bwrap() uses this to create/release the session
lock. The container name comes from read_image_ref(), promoted from a
list_oci_images()-only helper to public API in oci_image.h so
run_container() can reuse the same name/tag derivation for a single
image tar.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Gv3s5jckJKzh6JkMoi2Akz
2026-08-22 08:56:12 +00:00
ceamac 9877ffe7f1 Add --hostname to set the sandbox's hostname under -r/--run
Long-option only. Threaded through run_container() into
build_bwrap_args(), which passes it as bwrap's own --hostname only
when --unshare-uts is actually among the flags being given to bwrap
(bwrap itself refuses --hostname without it) -- otherwise logs a
warning and leaves the hostname alone, since a stock Android kernel
in degraded mode may not support a UTS namespace at all.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Gv3s5jckJKzh6JkMoi2Akz
2026-08-22 07:13:22 +00:00
ceamac 355675b43f Resolve HOME to the target user's home directory instead of /root
ResolvedUser now carries home, looked up from the image's own
/etc/passwd entry for the final resolved uid (falling back to /root
for uid 0 or / otherwise when there's no matching row). bwrap's HOME
now uses this whenever a user override applies (--user/--group or an
image-declared default user); the plain /root default is kept only
when no override applies at all.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Gv3s5jckJKzh6JkMoi2Akz
2026-08-22 06:47:16 +00:00
ceamac 545762d6de Reuse -v/--volume to mount named/host volumes into -r/--run
Volume names now reject '/', which lets a -v spec used with -r be told
apart as either an existing named volume or a host directory path. -v
becomes repeatable with -r, each mounting a volume at an absolute
container path; if the host directory is empty and the image already
has content there, it's copied in first (preserving numeric
ownership/permissions/links/xattrs-ACLs, degrading gracefully with a
warning if the host filesystem doesn't support xattrs). The
existence-check and copy run through the same nsenter-wrapped
namespace bwrap itself needs, since a rootless containers-storage
mount's content isn't otherwise visible to this process at all.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Gv3s5jckJKzh6JkMoi2Akz
2026-08-21 17:08:16 +00:00