zephyr/scripts/west_commands/zspdx/util.py
Steve Winslow fd31b9b4ac west: spdx: Generate SPDX 2.2 tag-value documents
This adds support to generate SPDX 2.2 tag-value documents via the
new west spdx command. The CMake file-based APIs are leveraged to
create relationships from source files to the corresponding
generated build files. SPDX-License-Identifier comments in source
files are scanned and filled into the SPDX documents.

Before `west build` is run, a specific file must be created in the
build directory so that the CMake API reply will run. This can be
done by running:

    west spdx --init -d BUILD_DIR

After `west build` is run, SPDX generation is then activated by
calling `west spdx`; currently this requires passing the build
directory as a parameter again:

    west spdx -d BUILD_DIR

This will generate three SPDX documents in `BUILD_DIR/spdx/`:

1) `app.spdx`: This contains the bill-of-materials for the
application source files used for the build.

2) `zephyr.spdx`: This contains the bill-of-materials for the
specific Zephyr source code files that are used for the build.

3) `build.spdx`: This contains the bill-of-materials for the built
output files.

Each file in the bill-of-materials is scanned, so that its hashes
(SHA256 and SHA1) can be recorded, along with any detected licenses
if an `SPDX-License-Identifier` appears in the file.

SPDX Relationships are created to indicate dependencies between
CMake build targets; build targets that are linked together; and
source files that are compiled to generate the built library files.

`west spdx` can be called with optional parameters for further
configuration:

* `-n PREFIX`: specifies a prefix for the Document Namespaces that
will be included in the generated SPDX documents. See SPDX spec 2.2
section 2.5 at
https://spdx.github.io/spdx-spec/2-document-creation-information/.
If -n is omitted, a default namespace will be generated according
to the default format described in section 2.5 using a random UUID.

* `-s SPDX_DIR`: specifies an alternate directory where the SPDX
documents should be written. If not specified, they will be saved
in `BUILD_DIR/spdx/`.

* `--analyze-includes`: in addition to recording the compiled
source code files (e.g. `.c`, `.S`) in the bills-of-materials, if
this flag is specified, `west spdx` will attempt to determine the
specific header files that are included for each `.c` file. This
will take longer, as it performs a dry run using the C compiler
for each `.c` file (using the same arguments that were passed to it
for the actual build).

* `--include-sdk`: if `--analyze-includes` is used, then adding
`--include-sdk` will create a fourth SPDX document, `sdk.spdx`,
which will list any header files included from the SDK.

Signed-off-by: Steve Winslow <steve@swinslow.net>
2021-05-05 11:14:06 -04:00

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Python

# Copyright (c) 2020, 2021 The Linux Foundation
#
# SPDX-License-Identifier: Apache-2.0
import hashlib
from west import log
def getHashes(filePath):
"""
Scan for and return hashes.
Arguments:
- filePath: path to file to scan.
Returns: tuple of (SHA1, SHA256, MD5) hashes for filePath, or
None if file is not found.
"""
hSHA1 = hashlib.sha1()
hSHA256 = hashlib.sha256()
hMD5 = hashlib.md5()
log.dbg(f" - getting hashes for {filePath}")
try:
with open(filePath, 'rb') as f:
buf = f.read()
hSHA1.update(buf)
hSHA256.update(buf)
hMD5.update(buf)
except OSError:
return None
return (hSHA1.hexdigest(), hSHA256.hexdigest(), hMD5.hexdigest())