Generate SBOM of the target product in file sbom.spdx.json in product out directory.

Original aosp/2374663 was reverted, so this change cnotains the implementation but disabled by default and SBOM will not be built by default with "m dist".

The feature will be enabled later in small CLs after running tests successfully in forrest.

Test: m sbom
Test: m dist
Test: on aosp, lunch aosp_bluejay-userdebug && m dist
Bug: 266726655
Change-Id: I926d0f97f3a0330ef61d059f12ea660005d370e6
diff --git a/tools/protos/metadata_file.proto b/tools/protos/metadata_file.proto
new file mode 100644
index 0000000..ac1129a
--- /dev/null
+++ b/tools/protos/metadata_file.proto
@@ -0,0 +1,281 @@
+// Copyright (C) 2023 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+syntax = "proto2";
+
+package metadata_file;
+
+// Proto definition of METADATA files of packages in AOSP codebase.
+message Metadata {
+  // Name of the package.
+  optional string name = 1;
+
+  // A short description (a few lines) of the package.
+  // Example: "Handles location lookups, throttling, batching, etc."
+  optional string description = 2;
+
+  // Specifies additional data about third-party packages.
+  optional ThirdParty third_party = 3;
+}
+
+message ThirdParty {
+  // URL(s) associated with the package.
+  //
+  // At a minimum, all packages must specify a URL which identifies where it
+  // came from, containing a type of: ARCHIVE, GIT or OTHER. Typically,
+  // a package should contain only a single URL from these types.  Occasionally,
+  // a package may be broken across multiple archive files for whatever reason,
+  // in which case having multiple ARCHIVE URLs is okay.  However, this should
+  // not be used to combine different logical packages that are versioned and
+  // possibly licensed differently.
+  repeated URL url = 1;
+
+  // The package version.  In order of preference, this should contain:
+  //  - If the package comes from Git or another source control system,
+  //    a specific tag or revision in source control, such as "r123" or
+  //    "58e27d2".  This MUST NOT be a mutable ref such as a branch name.
+  //  - a released package version such as "1.0", "2.3-beta", etc.
+  //  - the date the package was retrieved, formatted as "As of YYYY-MM-DD".
+  optional string version = 2;
+
+  // The date of the change in which the package was last upgraded from
+  // upstream.
+  // This should only identify package upgrades from upstream, not local
+  // modifications. This may identify the date of either the original or
+  // merged change.
+  //
+  // Note: this is NOT the date that this version of the package was released
+  // externally.
+  optional Date last_upgrade_date = 3;
+
+  // License type that identifies how the package may be used.
+  optional LicenseType license_type = 4;
+
+  // An additional note explaining the licensing of this package.  This is most
+  // commonly used with commercial license.
+  optional string license_note = 5;
+
+  // Description of local changes that have been made to the package.  This does
+  // not need to (and in most cases should not) attempt to include an exhaustive
+  // list of all changes, but may instead direct readers to review the local
+  // commit history, a collection of patch files, a separate README.md (or
+  // similar) document, etc.
+  // Note: Use of this field to store IDs of advisories fixed with a backported
+  // patch is deprecated, use "security.mitigated_security_patch" instead.
+  optional string local_modifications = 6;
+
+  // Security related metadata including risk category and any special
+  // instructions for using the package, as determined by an ISE-TPS review.
+  optional Security security = 7;
+
+  // The type of directory this metadata represents.
+  optional DirectoryType type = 8 [default = PACKAGE];
+
+  // The homepage for the package. This will eventually replace
+  // `url { type: HOMEPAGE }`
+  optional string homepage = 9;
+
+  // SBOM information of the package. It is mandatory for prebuilt packages.
+  oneof sbom {
+    // Reference to external SBOM document provided as URL.
+    SBOMRef sbom_ref = 10;
+  }
+
+}
+
+// URL associated with a third-party package.
+message URL {
+  enum Type {
+    // The homepage for the package. For example, "https://bazel.io/". This URL
+    // is optional, but encouraged to help disambiguate similarly named packages
+    // or to get more information about the package. This is especially helpful
+    // when no other URLs provide human readable resources (such as git:// or
+    // sso:// URLs).
+    HOMEPAGE = 1;
+
+    // The URL of the archive containing the source code for the package, for
+    // example a zip or tgz file.
+    ARCHIVE = 2;
+
+    // The URL of the upstream git repository this package is retrieved from.
+    // For example:
+    //  - https://github.com/git/git.git
+    //  - git://git.kernel.org/pub/scm/git/git.git
+    //
+    // Use of a git URL requires that the package "version" value must specify a
+    // specific git tag or revision.
+    GIT = 3;
+
+    // The URL of the upstream SVN repository this package is retrieved from.
+    // For example:
+    //  - http://llvm.org/svn/llvm-project/llvm/
+    //
+    // Use of an SVN URL requires that the package "version" value must specify
+    // a specific SVN tag or revision.
+    SVN = 4;
+
+    // The URL of the upstream mercurial repository this package is retrieved
+    // from. For example:
+    //   - https://mercurial-scm.org/repo/evolve
+    //
+    // Use of a mercurial URL requires that the package "version" value must
+    // specify a specific tag or revision.
+    HG = 5;
+
+    // The URL of the upstream darcs repository this package is retrieved
+    // from. For example:
+    //   - https://hub.darcs.net/hu.dwim/hu.dwim.util
+    //
+    // Use of a DARCS URL requires that the package "version" value must
+    // specify a specific tag or revision.
+    DARCS = 6;
+
+    PIPER = 7;
+
+    // A URL that does not fit any other type. This may also indicate that the
+    // source code was received via email or some other out-of-band way. This is
+    // most commonly used with commercial software received directly from the
+    // vendor. In the case of email, the URL value can be used to provide
+    // additional information about how it was received.
+    OTHER = 8;
+
+    // The URL identifying where the local copy of the package source code can
+    // be found.
+    //
+    // Typically, the metadata files describing a package reside in the same
+    // directory as the source code for the package. In a few rare cases where
+    // they are separate, the LOCAL_SOURCE URL identifies where to find the
+    // source code. This only describes where to find the local copy of the
+    // source; there should always be an additional URL describing where the
+    // package was retrieved from.
+    //
+    // Examples:
+    //  - https://android.googlesource.com/platform/external/apache-http/
+    LOCAL_SOURCE = 9;
+  }
+
+  // The type of resource this URL identifies.
+  optional Type type = 1;
+
+  // The actual URL value.  URLs should be absolute and start with 'http://' or
+  // 'https://' (or occasionally 'git://' or 'ftp://' where appropriate).
+  optional string value = 2;
+}
+
+// License type that identifies how the packages may be used.
+enum LicenseType {
+  BY_EXCEPTION_ONLY = 1;
+  NOTICE = 2;
+  PERMISSIVE = 3;
+  RECIPROCAL = 4;
+  RESTRICTED_IF_STATICALLY_LINKED = 5;
+  RESTRICTED = 6;
+  UNENCUMBERED = 7;
+}
+
+// Identifies security related metadata including risk category and any special
+// instructions for using the package.
+message Security {
+  // Security risk category for a package, as determined by an ISE-TPS review.
+  enum Category {
+    CATEGORY_UNSPECIFIED = 0;
+
+    // Package should only be used in a sandboxed environment.
+    // Package should have restricted visibility.
+    SANDBOXED_ONLY = 1;
+
+    // Package should not be used to process user content. It is considered
+    // safe to use to process trusted data only. Package should have restricted
+    // visibility.
+    TRUSTED_DATA_ONLY = 2;
+
+    // Package is considered safe to use.
+    REVIEWED_AND_SECURE = 3;
+  }
+
+  // Identifies the security risk category for the package.  This will be
+  // provided by the ISE-TPS team as the result of a security review of the
+  // package.
+  optional Category category = 1;
+
+  // An additional security note for the package.
+  optional string note = 2;
+
+  // Text tag to categorize the package. It's currently used by security to:
+  // - to disable OSV (https://osv.dev)
+  // support via the `OSV:disable` tag
+  // - to attach CPE to their corresponding packages, for vulnerability
+  // monitoring:
+  //
+  // Please do document your usecase here should you want to add one.
+  repeated string tag = 3;
+
+  // ID of advisories fixed with a mitigated patch, for example CVE-2018-1111.
+  repeated string mitigated_security_patch = 4;
+}
+
+enum DirectoryType {
+  UNDEFINED = 0;
+
+  // This directory represents a package.
+  PACKAGE = 1;
+
+  // This directory is designed to organize multiple third-party PACKAGE
+  // directories.
+  GROUP = 2;
+
+  // This directory contains several PACKAGE directories representing
+  // different versions of the same third-party project.
+  VERSIONS = 3;
+}
+
+// Represents a whole or partial calendar date, such as a birthday. The time of
+// day and time zone are either specified elsewhere or are insignificant. The
+// date is relative to the Gregorian Calendar. This can represent one of the
+// following:
+//
+// * A full date, with non-zero year, month, and day values.
+// * A month and day, with a zero year (for example, an anniversary).
+// * A year on its own, with a zero month and a zero day.
+// * A year and month, with a zero day (for example, a credit card expiration
+//   date).
+message Date {
+  // Year of the date. Must be from 1 to 9999, or 0 to specify a date without
+  // a year.
+  optional int32 year = 1;
+  // Month of a year. Must be from 1 to 12, or 0 to specify a year without a
+  // month and day.
+  optional int32 month = 2;
+  // Day of a month. Must be from 1 to 31 and valid for the year and month, or 0
+  // to specify a year by itself or a year and month where the day isn't
+  // significant.
+  optional int32 day = 3;
+}
+
+// Reference to external SBOM document and element corresponding to the package.
+// See https://spdx.github.io/spdx-spec/v2.3/document-creation-information/#66-external-document-references-field
+message SBOMRef {
+  // The URL that points to the SBOM document of the upstream package of this
+  // third_party package.
+  optional string url = 1;
+  // Checksum of the SBOM document the url field points to.
+  // Format: e.g. SHA1:<checksum>, or any algorithm defined in
+  // https://spdx.github.io/spdx-spec/v2.3/file-information/#8.4
+  optional string checksum = 2;
+  // SPDXID of the upstream package/file defined in the SBOM document the url field points to.
+  // Format: SPDXRef-[a-zA-Z0-9.-]+, see
+  // https://spdx.github.io/spdx-spec/v2.3/package-information/#72-package-spdx-identifier-field or
+  // https://spdx.github.io/spdx-spec/v2.3/file-information/#82-file-spdx-identifier-field
+  optional string element_id = 3;
+}
\ No newline at end of file