Proper mount namespace configuration for bionic
This CL fixes the design problem of the previous mechanism for providing
the bootstrap bionic and the runtime bionic to the same path.
Previously, bootstrap bionic was self-bind-mounted; i.e.
/system/bin/libc.so is bind-mounted to itself. And the runtime bionic
was bind-mounted on top of the bootstrap bionic. This has not only caused
problems like `adb sync` not working(b/122737045), but also is quite
difficult to understand due to the double-and-self mounting.
This is the new design:
Most importantly, these four are all distinct:
1) bootstrap bionic (/system/lib/bootstrap/libc.so)
2) runtime bionic (/apex/com.android.runtime/lib/bionic/libc.so)
3) mount point for 1) and 2) (/bionic/lib/libc.so)
4) symlink for 3) (/system/lib/libc.so -> /bionic/lib/libc.so)
Inside the mount namespace of the pre-apexd processes, 1) is
bind-mounted to 3). Likewise, inside the mount namespace of the
post-apexd processes, 2) is bind-mounted to 3). In other words, there is
no self-mount, and no double-mount.
Another change is that mount points are under /bionic and the legacy
paths become symlinks to the mount points. This is to make sure that
there is no bind mounts under /system, which is breaking some apps.
Finally, code for creating mount namespaces, mounting bionic, etc are
refactored to mount_namespace.cpp
Bug: 120266448
Bug: 123275379
Test: m, device boots, adb sync/push/pull works,
especially with following paths:
/bionic/lib64/libc.so
/bionic/bin/linker64
/system/lib64/bootstrap/libc.so
/system/bin/bootstrap/linker64
Change-Id: Icdfbdcc1efca540ac854d4df79e07ee61fca559f
diff --git a/rootdir/etc/ld.config.txt b/rootdir/etc/ld.config.txt
index d0e84df..6d0c5b3 100644
--- a/rootdir/etc/ld.config.txt
+++ b/rootdir/etc/ld.config.txt
@@ -73,6 +73,8 @@
namespace.default.permitted.paths += /%PRODUCT_SERVICES%/priv-app
namespace.default.permitted.paths += /data
namespace.default.permitted.paths += /mnt/expand
+namespace.default.permitted.paths += /bionic/${LIB}
+namespace.default.permitted.paths += /system/${LIB}/bootstrap
namespace.default.asan.search.paths = /data/asan/system/${LIB}
namespace.default.asan.search.paths += /system/${LIB}
@@ -104,6 +106,8 @@
namespace.default.asan.permitted.paths += /%PRODUCT_SERVICES%/app
namespace.default.asan.permitted.paths += /%PRODUCT_SERVICES%/priv-app
namespace.default.asan.permitted.paths += /mnt/expand
+namespace.default.asan.permitted.paths += /bionic/${LIB}
+namespace.default.asan.permitted.paths += /system/${LIB}/bootstrap
# Keep in sync with ld.config.txt in the com.android.runtime APEX.
namespace.default.links = runtime,resolv
diff --git a/rootdir/init.rc b/rootdir/init.rc
index d081666..4a19e39 100644
--- a/rootdir/init.rc
+++ b/rootdir/init.rc
@@ -12,6 +12,12 @@
import /init.${ro.zygote}.rc
on early-init
+ # Mount shared so changes propagate into child namespaces
+ # Do this before other processes are started from init. Otherwise,
+ # processes launched while the propagation type of / is 'private'
+ # won't get mount events from others.
+ mount rootfs rootfs / shared rec
+
# Set init and its forked children's oom_adj.
write /proc/1/oom_score_adj -1000
@@ -346,8 +352,6 @@
# Once everything is setup, no need to modify /.
# The bind+remount combination allows this to work in containers.
mount rootfs rootfs / remount bind ro nodev
- # Mount shared so changes propagate into child namespaces
- mount rootfs rootfs / shared rec
# Mount default storage into root namespace
mount none /mnt/runtime/default /storage bind rec
mount none none /storage slave rec
@@ -583,6 +587,14 @@
# Check any timezone data in /data is newer than the copy in the runtime module, delete if not.
exec - system system -- /system/bin/tzdatacheck /apex/com.android.runtime/etc/tz /data/misc/zoneinfo
+ # Wait for apexd to finish activating APEXes before starting more processes.
+ # This certainly reduces the parallelism but is required to make as many processes
+ # as possible to use the bionic libs from the runtime APEX. This takes less than 50ms
+ # so the impact on the booting time is not significant.
+ wait_for_prop apexd.status ready
+ setup_runtime_bionic
+ parse_apex_configs
+
# If there is no post-fs-data action in the init.<device>.rc file, you
# must uncomment this line, otherwise encrypted filesystems
# won't work.
@@ -804,6 +816,3 @@
service flash_recovery /system/bin/install-recovery.sh
class main
oneshot
-
-on property:apexd.status=ready
- parse_apex_configs