[OE-core][PATCH v2] spdx: Add yocto PURLs

[Joshua Watt <jpewhacker@gmail.com>]

Adds code to add PURLs to packages based on the PURL specification for
Yocto packages [1].

The SPDX_PACKAGE_URL variable is renamed SPDX_PACKAGE_URLS to make it
clear that it can now be a list of PURLs. SPDX_PACKAGE_URL is retained,
but marked as deprecated.

[1]: https://github.com/package-url/purl-spec/blob/main/types-doc/yocto-definition.md

Signed-off-by: Joshua Watt <JPEWhacker@gmail.com>
---
 meta/classes/create-spdx-3.0.bbclass | 11 ++++++++-
 meta/lib/oe/__init__.py              |  2 +-
 meta/lib/oe/purl.py                  | 34 ++++++++++++++++++++++++++++
 meta/lib/oe/spdx30_tasks.py          | 21 ++++++++++++-----
 4 files changed, 60 insertions(+), 8 deletions(-)
 create mode 100644 meta/lib/oe/purl.py

diff --git a/meta/classes/create-spdx-3.0.bbclass b/meta/classes/create-spdx-3.0.bbclass
index 96c0b9722b..d4575d61c4 100644
--- a/meta/classes/create-spdx-3.0.bbclass
+++ b/meta/classes/create-spdx-3.0.bbclass
@@ -131,7 +131,16 @@ SPDX_PACKAGE_VERSION[doc] = "The version of a package, software_packageVersion \
 SPDX_PACKAGE_URL ??= ""
 SPDX_PACKAGE_URL[doc] = "Provides a place for the SPDX data creator to record \
 the package URL string (in accordance with the Package URL specification) for \
-a software Package."
+a software Package. DEPRECATED - use SPDX_PACKAGE_URLS instead"
+
+SPDX_PACKAGE_URLS ?= "${SPDX_PACKAGE_URL} ${@oe.purl.get_base_purl(d)}"
+SPDX_PACKAGE_URLS[doc] = "A space separated list of Package URLs (purls) for \
+    the software Package. The first item in this list will be listed as the \
+    packageUrl property of the packages, and all purls (including the first \
+    one) will be listed as external references. The default value is an auto \
+    generated pkg:yocto purl based on the recipe name, version, and layer name. \
+    Override this variable to replace the default, otherwise append or prepend \
+    to add additional purls."
 
 IMAGE_CLASSES:append = " create-spdx-image-3.0"
 SDK_CLASSES += "create-spdx-sdk-3.0"
diff --git a/meta/lib/oe/__init__.py b/meta/lib/oe/__init__.py
index 9e4134c483..13d887a4aa 100644
--- a/meta/lib/oe/__init__.py
+++ b/meta/lib/oe/__init__.py
@@ -12,4 +12,4 @@ __path__ = extend_path(__path__, __name__)
 BBIMPORTS = ["qa", "data", "path", "utils", "types", "package", "packagedata", \
              "packagegroup", "sstatesig", "lsb", "cachedpath", "license", "qemu", \
              "reproducible", "rust", "buildcfg", "go", "spdx30_tasks", "spdx_common", \
-             "cve_check", "tune", "classextend"]
+             "cve_check", "tune", "classextend", "purl"]
diff --git a/meta/lib/oe/purl.py b/meta/lib/oe/purl.py
new file mode 100644
index 0000000000..2f92a23596
--- /dev/null
+++ b/meta/lib/oe/purl.py
@@ -0,0 +1,34 @@
+#
+# Copyright OpenEmbedded Contributors
+#
+# SPDX-License-Identifier: GPL-2.0-only
+#
+
+import urllib.parse
+
+PREFIX = "pkg:yocto"
+
+
+def quote(s):
+    """
+    Returns the percent encoded version of the string, suitable for including
+    in a PURL field
+    """
+    return urllib.parse.quote(s, safe="")
+
+
+def get_base_purl(d):
+    """
+    Returns the base PURL for the current recipe (that is, the PURL without any
+    additional qualifiers)
+    """
+    layername = d.getVar("FILE_LAYERNAME")
+    bpn = d.getVar("BPN")
+    pv = d.getVar("PV")
+
+    name = f"{quote(bpn.lower())}@{quote(pv)}"
+
+    if layername:
+        return f"{PREFIX}/{quote(layername.lower())}/{name}"
+
+    return f"{PREFIX}/{name}"
diff --git a/meta/lib/oe/spdx30_tasks.py b/meta/lib/oe/spdx30_tasks.py
index f731a709e3..01e7dcbbc6 100644
--- a/meta/lib/oe/spdx30_tasks.py
+++ b/meta/lib/oe/spdx30_tasks.py
@@ -639,12 +639,21 @@ def create_spdx(d):
             set_var_field("SUMMARY", spdx_package, "summary", package=package)
             set_var_field("DESCRIPTION", spdx_package, "description", package=package)
 
-            if d.getVar("SPDX_PACKAGE_URL:%s" % package) or d.getVar("SPDX_PACKAGE_URL"):
-                set_var_field(
-                    "SPDX_PACKAGE_URL",
-                    spdx_package,
-                    "software_packageUrl",
-                    package=package
+            purls = (
+                d.getVar("SPDX_PACKAGE_URLS:%s" % package)
+                or d.getVar("SPDX_PACKAGE_URLS")
+                or ""
+            ).split()
+
+            if purls:
+                spdx_package.software_packageUrl = purls[0]
+
+            for p in sorted(set(purls)):
+                spdx_package.externalIdentifier.append(
+                    oe.spdx30.ExternalIdentifier(
+                        externalIdentifierType=oe.spdx30.ExternalIdentifierType.packageUrl,
+                        identifier=p,
+                    )
                 )
 
             pkg_objset.new_scoped_relationship(
-- 
2.52.0