android-tools: make adbd fs_config opt-in via PACKAGECONFIG

On non-Android builds should_use_fs_config() in adbd's
file_sync_service.cpp unconditionally returns true, so every
`adb push` destination, including paths under /data, is routed through
Android's fs_config tables. Those tables have a catch-all directory entry
for "data" (mode 0771, AID_SYSTEM) but no equivalent file entry, so a
freshly pushed directory and the file inside it end up with inconsistent
owners, and non-root/system processes can't list the directory.

On non-Android builds should_use_fs_config() now returns false by
default: adbd then honours the mode sent by the host and leaves
ownership untouched.

Add a "fs-config" PACKAGECONFIG (disabled by default) which defines
ADBD_USE_FS_CONFIG and re-enables fs_config, scoped to /system, /vendor
and /oem, for BSPs that rely on it.

Behaviour change: fs_config is no longer applied on non-Android builds
unless PACKAGECONFIG contains "fs-config".

AI-Generated: Uses Claude Code (Claude Sonnet 5.5)

Signed-off-by: Etienne Cordonnier <ecordonnier@snap.com>
Signed-off-by: Khem Raj <khem.raj@oss.qualcomm.com>

meta-oe/recipes-devtools/android-tools/android-tools/0015-adbd-make-fs-config-opt-in-on-non-android-builds.patch

@@ -0,0 +1,60 @@
+Subject: [PATCH] adbd: make fs_config opt-in on non-Android builds
+
+should_use_fs_config() exists to restrict Android's fs_config-based
+ownership/mode table to the partitions it actually describes
+(/system, /vendor, /oem), with a compatibility carve-out that also
+excludes /data on older on-device Android API levels. That carve-out
+is guarded by `#if defined(__ANDROID__)`, so on a non-Android (Linux
+host) build of adbd it never applies, and the function unconditionally
+returns true instead.
+
+As a result, every `adb push` destination -- including arbitrary
+paths under /data -- gets routed through fs_config's android_dirs/
+android_files tables. Those tables define a catch-all directory entry
+for "data" (mode 0771, uid/gid AID_SYSTEM) but no equivalent catch-all
+file entry, so a freshly pushed directory and the file inside it end
+up with different, Android-partition-image-derived owners instead of
+both simply being owned by whoever ran the push. Mode 0771 also means
+a process that isn't root or system can traverse such a directory but
+not list its contents, which breaks any non-privileged service trying
+to iterate a pushed directory tree.
+
+fs_config's table has nothing meaningful to say about a generic Linux
+rootfs, so on non-Android builds disable it by default, which makes adbd
+honour the mode sent by the host and leave ownership untouched. Builds
+that do rely on fs_config can define ADBD_USE_FS_CONFIG, in which case
+it is applied only to /system, /vendor and /oem.
+
+Upstream-Status: Pending
+
+Signed-off-by: Etienne Cordonnier <ecordonnier@snap.com>
+---
+ packages/modules/adb/daemon/file_sync_service.cpp | 13 ++++++++++++-
+ 1 file changed, 12 insertions(+), 1 deletion(-)
+
+diff --git a/packages/modules/adb/daemon/file_sync_service.cpp b/packages/modules/adb/daemon/file_sync_service.cpp
+--- a/packages/modules/adb/daemon/file_sync_service.cpp
++++ b/packages/modules/adb/daemon/file_sync_service.cpp
+@@ -81,8 +81,19 @@ static bool should_use_fs_config([[maybe_unused]] const std::string& path) {
+     if (android_get_device_api_level() < __ANDROID_API_V__) {
+         return !android::base::StartsWith(path, "/data/");
+     }
+-#endif
+     return true;
++#elif defined(ADBD_USE_FS_CONFIG)
++    // Non-Android (Linux host) build with fs_config enabled: its tables only
++    // describe the system partitions, so keep it scoped to those rather than
++    // letting it apply to arbitrary pushed paths such as /data.
++    return android::base::StartsWith(path, "/system/") ||
++           android::base::StartsWith(path, "/vendor/") ||
++           android::base::StartsWith(path, "/oem/");
++#else
++    // Non-Android build, fs_config disabled: use the mode sent by the host and
++    // don't change ownership.
++    return false;
++#endif
+ }
+ 
+ static bool update_capabilities(const char* path, uint64_t capabilities) {
+--
+2.43.0

meta-oe/recipes-devtools/android-tools/android-tools_35.0.2.bb

@@ -60,6 +60,7 @@ SRC_URI = "https://deb.debian.org/debian/pool/main/a/android-platform-tools/andr
            file://0012-libbase-off64_t-extend-non-glibc-compat-typedef-to-musl.patch \
            file://0013-adb-sysdeps-provide-pread64-pwrite64-lseek64-fallba.patch \
            file://0014-daemon-auth-vendor-a-portable-b64_pton-for-non-glib.patch \
+           file://0015-adbd-make-fs-config-opt-in-on-non-android-builds.patch \
            "
 
 SRC_URI[orig.md5sum] = "352376965cdef7bd7505d8fefdd43d50"
@@ -98,6 +99,7 @@ CFLAGS:append:libc-musl = " -DANDROID_HOST_MUSL"
 # path instead of the broken compile-time one.
 CXXFLAGS:append = " -fPIC -std=gnu++20 -D_Nonnull= -D_Nullable= -I${STAGING_INCDIR}/boringssl -DFMT_CONSTEVAL="
 CXXFLAGS:append:libc-musl = " -DANDROID_HOST_MUSL"
+CXXFLAGS:append = "${@bb.utils.contains('PACKAGECONFIG', 'fs-config', ' -DADBD_USE_FS_CONFIG', '', d)}"
 LDFLAGS:append = " -fPIC -L${STAGING_LIBDIR}/android"
 
 
@@ -259,4 +261,8 @@ FILES:${PN}-adbd = " \
 BBCLASSEXTEND = "native"
 
 PACKAGECONFIG ??= "${@bb.utils.filter('DISTRO_FEATURES', 'systemd', d)}"
+# Apply Android's fs_config ownership/mode tables to files pushed by adbd to
+# /system, /vendor and /oem. Off by default: the tables describe Android
+# partition images and are meaningless on a generic Linux rootfs.
+PACKAGECONFIG[fs-config] = ""
 PACKAGECONFIG[systemd] = ",,systemd"