[PATCH v2 4/9] oe-selftest/cpp-example: fix conf file ownership with static UIDs/GIDs

[AdrianF <adrian.freihofer@siemens.com>]

From: Adrian Freihofer <adrian.freihofer@siemens.com>

test_devtool_ide_sdk_none_qemu builds an image containing both
cmake-example and meson-example, starts a QEMU instance, then uses
devtool ide-sdk + devtool deploy-target to rebuild and redeploy each
recipe in turn. The test verifies that /etc/<recipe>.conf is owned by
the matching user both before and after each deploy cycle.

The test was failing with:

  /etc/meson-example.conf not owned by user meson-example: got cmake-example

Root cause: both recipes call

  install -m 0644 -o ${BPN} -g ${BPN} ... ${D}${sysconfdir}/${BPN}.conf

During do_install, pseudo resolves ${BPN} to a UID by looking up
/etc/passwd in the recipe's own isolated RECIPE_SYSROOT. Since the
sysroots are independent, both cmake-example and meson-example each
see themselves as the first --system user and get the same UID (e.g.
100). Both ${D} trees therefore contain files with UID 100. In the
final rootfs cmake-example is allocated UID 100 and meson-example UID
101. Files packaged for meson-example still carry UID 100, so stat
reports them as owned by cmake-example.

A pkg_postinst chown would fix the rootfs, but devtool deploy-target
is a plain tar pipe over SSH with no package-manager involvement - it
never runs pkg_postinst. Whatever UID is embedded in ${D} is what
lands on the target. Not sure how this could be fixed with dynamic UIDs.

A clean solution is to make every recipe sysroot and the final image
agree on the same UIDs from the start, i.e. static IDs.

Fix:
- Enable USERADDEXTENSION = "useradd-staticids" in _write_bb_config so
  the test builds with static IDs for the duration of the test.
- Add cmake-example (UID/GID 533) and meson-example (UID/GID 534) to
  meta-selftest/files/static-passwd and static-group.
- Expand the comment in cpp-example.inc's do_install to document the
  static-ID requirement so future readers understand why the -o/-g
  flags work correctly only under useradd-staticids.
- Fix a copy-paste error in the in-test comment (said
  "meson-example.conf ... cmake-example user" for the cmake block).

Signed-off-by: Adrian Freihofer <adrian.freihofer@siemens.com>
---
 meta-selftest/files/static-group               |  2 ++
 meta-selftest/files/static-passwd              |  2 ++
 meta-selftest/recipes-test/cpp/cpp-example.inc |  6 +++++-
 meta/lib/oeqa/selftest/cases/devtool.py        | 14 ++++++++++++--
 4 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/meta-selftest/files/static-group b/meta-selftest/files/static-group
index 3fca4aa5c9..adf436f310 100644
--- a/meta-selftest/files/static-group
+++ b/meta-selftest/files/static-group
@@ -28,4 +28,6 @@ ptest:x:529:
 xuser:x:530:
 seat:x:531:
 audio:x:532:
+cmake-example:x:533:
+meson-example:x:534:
 nogroup:x:65534:
diff --git a/meta-selftest/files/static-passwd b/meta-selftest/files/static-passwd
index cc6c5acd5c..8d9f149b9f 100644
--- a/meta-selftest/files/static-passwd
+++ b/meta-selftest/files/static-passwd
@@ -19,3 +19,5 @@ _apt:x:523:523::/:/bin/nologin
 weston:x:525:525::/:/bin/nologin
 ptest:x:529:529::/:/bin/nologin
 xuser:x:530:530::/:/bin/nologin
+cmake-example:x:533:533::/var/lib/cmake-example:/bin/false
+meson-example:x:534:534::/var/lib/meson-example:/bin/false
diff --git a/meta-selftest/recipes-test/cpp/cpp-example.inc b/meta-selftest/recipes-test/cpp/cpp-example.inc
index 2653f45e90..0671824d1c 100644
--- a/meta-selftest/recipes-test/cpp/cpp-example.inc
+++ b/meta-selftest/recipes-test/cpp/cpp-example.inc
@@ -41,7 +41,11 @@ USERADD_PARAM:${PN} = "--system --home /var/lib/${BPN} --no-create-home --shell
 EX_BINARY_NAME ?= "${BPN}"
 
 do_install:append() {
-    # Install configuration file owned by unprivileged user
+    # Install configuration file owned by the recipe's unprivileged user.
+    # Note: this requires static UIDs/GIDs (USERADDEXTENSION = "useradd-staticids")
+    # so that the UID embedded by pseudo during do_install matches the UID assigned
+    # in the final image. devtool deploy-target is a raw file copy and does not run
+    # pkg_postinst, so the UID in ${D} must already be correct.
     install -d ${D}${sysconfdir}
     install -m 0644 -g ${BPN} -o ${BPN} ${S}/cpp-example.conf ${D}${sysconfdir}/${BPN}.conf
     sed -i -e 's|@BINARY_NAME@|${BPN}|g' ${D}${sysconfdir}/${BPN}.conf
diff --git a/meta/lib/oeqa/selftest/cases/devtool.py b/meta/lib/oeqa/selftest/cases/devtool.py
index dc83d406fd..bccbae912f 100644
--- a/meta/lib/oeqa/selftest/cases/devtool.py
+++ b/meta/lib/oeqa/selftest/cases/devtool.py
@@ -2597,7 +2597,17 @@ class DevtoolIdeSdkTests(DevtoolBase):
             'IMAGE_GEN_DEBUGFS = "1"',
             'IMAGE_INSTALL:append = " gdbserver %s"' % ' '.join(
                 [r + '-ptest' for r in recipe_names]),
-            'DISTRO_FEATURES:append = " ptest"'
+            'DISTRO_FEATURES:append = " ptest"',
+            # Static UIDs/GIDs are required so that files installed via
+            # "install -o ${BPN}" in do_install embed the same UID that gets
+            # assigned in the final image. Without this, each recipe's isolated
+            # sysroot allocates UIDs independently (both start at the first free
+            # system UID), so files end up with colliding UIDs in the image.
+            # devtool deploy-target is a raw file copy and does not run
+            # pkg_postinst, so ownership must be correct already in ${D}.
+            'USERADDEXTENSION = "useradd-staticids"',
+            'USERADD_UID_TABLES += "files/static-passwd"',
+            'USERADD_GID_TABLES += "files/static-group"',
         ]
         self.write_config("\n".join(conf_lines))
 
@@ -2985,7 +2995,7 @@ class DevtoolIdeSdkTests(DevtoolBase):
             self.assertEqual(self._workspace_scripts_dir(
                 recipe_name), self._sources_scripts_dir(tempdir))
 
-            # Verify /etc/meson-example.conf is still owned by the cmake-example user
+            # Verify /etc/cmake-example.conf is still owned by the cmake-example user
             # after the install and deploy scripts updated the file
             self._verify_conf_file(qemu, conf_file, example_exe, example_exe)
 
-- 
2.53.0