Add rpm fileattr generator for dlopen-notes

README.md

@@ -97,6 +97,19 @@ $ dlopen-notes /usr/lib64/systemd/libsystemd-shared-257.so
 ...
 ```
 
+### Using the rpm fileattr generator
+
+The tool that processes package notes can be hooked into the rpm build process
+to automatically generate virtual `Requires`, `Recommends`, and `Suggests` dependencies.
+
+The rpm file attribute mechanism is described in
+[rpm-dependency-generators.7](https://rpm-software-management.github.io/rpm/man/rpm-dependency-generators.7).
+
+This tool implements the 'multifile' protocol:
+it reads the list of files on stdin and outputs a list of virtual dependencies.
+
+See the `rpm/dlopen_notes.attr` file for invocation details and options.
+
 ## Requirements
 * binutils (>= 2.39)
 * mold (>= 1.3.0)

dlopen-notes.py

@@ -7,6 +7,7 @@
 
 import argparse
 import enum
+import fnmatch
 import functools
 import json
 import sys
@@ -19,6 +20,11 @@
 except ImportError:
     print_json = print
 
+def dictify(f):
+    def wrap(*args, **kwargs):
+        return dict(f(*args, **kwargs))
+    return functools.update_wrapper(wrap, f)
+
 def listify(f):
     def wrap(*args, **kwargs):
         return list(f(*args, **kwargs))
@@ -63,11 +69,6 @@ def notes(self):
 
                 yield from j
 
-def dictify(f):
-    def wrap(*args, **kwargs):
-        return dict(f(*args, **kwargs))
-    return functools.update_wrapper(wrap, f)
-
 @dictify
 def group_by_soname(elffiles):
     for elffile in elffiles:
@@ -84,6 +85,16 @@ class Priority(enum.Enum):
     def __lt__(self, other):
         return self.value < other.value
 
+    def rpm_name(self):
+        if self == self.__class__.suggested:
+            return 'Suggests'
+        if self == self.__class__.recommended:
+            return 'Recommends'
+        if self == self.__class__.required:
+            return 'Requires'
+        raise ValueError
+
+
 def group_by_feature(elffiles):
     features = {}
 
@@ -143,6 +154,52 @@ def generate_rpm(elffiles, stanza, filter):
                 soname = next(iter(note['soname']))  # we take the first — most recommended — soname
                 yield f"{stanza}: {soname}{suffix}"
 
+def rpm_fileattr_generator(args):
+    if args.rpm_features is not None:
+        if not any(fnmatch.fnmatch(args.subpackage, pattern[0])
+                   for pattern in args.rpm_features):
+            # Current subpackage is not listed, nothing to do.
+            # Consume all input as required by the protocol.
+            sys.stdin.read()
+            return
+
+    for file in sys.stdin:
+        file = file.strip()
+        if not file:
+            continue  # ignore empty lines
+
+        elffile = ELFFileReader(file)
+        suffix = '()(64bit)' if elffile.elffile.elfclass == 64 else ''
+
+        first = True
+
+        for note in elffile.notes():
+            # Feature name is optional. Allow this to be matched
+            # by the empty string ('') or a wildcard glob ('*').
+            feature = note.get('feature', '')
+
+            if args.rpm_features is not None:
+                for package_pattern,feature_pattern in args.rpm_features:
+                    if (fnmatch.fnmatch(args.subpackage, package_pattern) and
+                        fnmatch.fnmatch(feature, feature_pattern)):
+                        break
+                else:
+                    # not matched
+                    continue
+            else:
+                # if no mapping, print all features at the suggested level
+                level = Priority[note.get('priority', 'recommended')].rpm_name()
+                if level != args.rpm_fileattr:
+                    continue
+
+            if first:
+                print(f';{file}')
+                first = False
+
+            soname = next(iter(note['soname']))  # we take the first — most recommended — soname
+            print(f'{soname}{suffix}')
+
+
 def make_parser():
     p = argparse.ArgumentParser(
         description=__doc__,
@@ -187,10 +244,28 @@ def make_parser():
         metavar='FEATURE1,FEATURE2',
         help='Generate rpm Recommends for listed features',
     )
+    p.add_argument(
+        '--rpm-fileattr',
+        metavar='TYPE',
+        help='Run as rpm fileattr generator for TYPE dependencies',
+    )
+    p.add_argument(
+        '--subpackage',
+        metavar='NAME',
+        default='',
+        help='Current subpackage NAME',
+    )
+    p.add_argument(
+        '--rpm-features',
+        metavar='SUBPACKAGE:FEATURE,SUBPACKAGE:FEATURE',
+        type=lambda s: [x.split(':', maxsplit=1) for x in s.split(',')],
+        action='extend',
+        help='Specify subpackage:feature mapping',
+    )
     p.add_argument(
         'filenames',
-        nargs='+',
-        metavar='filename',
+        nargs='*',
+        metavar='FILENAME',
         help='Library file to extract notes from',
     )
     p.add_argument(
@@ -207,15 +282,30 @@ def parse_args():
         and not args.sonames
         and args.features is None
         and args.rpm_requires is None
-        and args.rpm_recommends is None):
+        and args.rpm_recommends is None
+        and args.rpm_fileattr is None):
         # Make --raw the default if no action is specified.
         args.raw = True
 
+    if args.rpm_fileattr is not None:
+        if (args.filenames
+            or args.raw
+            or args.features is not None
+            or args.rpm_requires
+            or args.rpm_recommends):
+            raise ValueError('--rpm-generate cannot be combined with most options')
+
+    if args.rpm_fileattr is None and not args.filenames:
+        raise ValueError('At least one positional FILENAME parameter is required')
+
     return args
 
 if __name__ == '__main__':
     args = parse_args()
 
+    if args.rpm_fileattr is not None:
+        sys.exit(rpm_fileattr_generator(args))
+
     elffiles = [ELFFileReader(filename) for filename in args.filenames]
     features = group_by_feature(elffiles)
 

fakelib/fakelib.spec

@@ -0,0 +1,36 @@
+# SPDX-License-Identifier: MIT-0
+#
+# This file is part of the package-notes package.
+
+Name:           fakelib
+Version:        0
+Release:        %autorelease
+Summary:        %{name}
+
+License:        None
+
+%define __dlopen_notes_requires_opts   --rpm-features=fakelib:gcrypt,fakelib:lz4
+%define __dlopen_notes_recommends_opts --rpm-features=*:zstd
+%define __dlopen_notes_suggests_opts   --rpm-features=fakelib:lzm[abc]
+
+#undefine _dlopen_notes_generator
+
+%description
+%{summary}.
+
+%prep
+
+%build
+
+%install
+install -Dt %{buildroot}/usr/lib64/ /usr/lib64/libsystemd.so.0
+ln -s libsystemd.so.0 %{buildroot}/usr/lib64/libsystemd.so
+install -Dt %{buildroot}/usr/lib64/ /usr/lib64/libmvec.so.1
+
+%files
+/usr/lib64/libsystemd.so.0
+/usr/lib64/libsystemd.so
+/usr/lib64/libmvec.so.1
+
+%changelog
+%autochangelog

rpm/dlopen_notes.attr

@@ -0,0 +1,44 @@
+# SPDX-License-Identifier: MIT-0
+#
+# This file is part of the package-notes package.
+#
+#
+# The spec file for a package can specify which features are listed
+# and at which level, using
+# '--rpm-features=SUBPACKAGE1:FEATURE1,SUBPACKAGE2:FEATURE2' option in
+# the '__dlopen_notes_TYPE_opts' macro, where TYPE is one of
+# 'requires', 'recommends', or 'suggests'. The macro should be declared
+# in the spec file using:
+#   %define __dlopen_notes_TYPE_opts SUBPACKAGE:FEATURE…
+# e.g.
+#   %define __dlopen_notes_recommends_opts *:zstd
+#
+# The option accepts multiple comma-separated pairs, and can also be
+# specified multiple times. Both the subpackage name and feature name
+# can be a glob. If configuration is omitted, the priority recommended
+# in the notes is used.
+#
+# The '--subpackage=SUBPACKAGE' option (inserted below) tells the generator
+# which subpackage is being processed.
+#
+# For example, for a package using compression libraries, we can say
+# that the 'package-libs' subpackage shall carry 'Requires' on all the
+# libraries needed for the 'zstd' feature, all subpackages shall carry
+# 'Recommends' on all the libraries needed for the 'gzip' feature, and
+# the 'package' subpackage shall carry 'Suggests' for any feature
+# matching 'lzma' or 'bzip*'.
+#
+#  %define __dlopen_notes_requires_opts   --rpm-features=package-libs:zstd
+#  %define __dlopen_notes_recommends_opts --rpm-features=*:gzip
+#  %define __dlopen_notes_suggests_opts   --rpm-features=package:lzma,package:bzip*
+#
+# To opt out, undefine the %_dlopen_notes_generator macro:
+#  %undefine _dlopen_notes_generator
+
+%_dlopen_notes_generator   %{_bindir}/dlopen-notes
+
+%__dlopen_notes_requires   %{!?_dlopen_notes_generator:true }%{_dlopen_notes_generator} --subpackage='%{name}' --rpm-fileattr=Requires
+%__dlopen_notes_recommends %{!?_dlopen_notes_generator:true }%{_dlopen_notes_generator} --subpackage='%{name}' --rpm-fileattr=Recommends
+%__dlopen_notes_suggests   %{!?_dlopen_notes_generator:true }%{_dlopen_notes_generator} --subpackage='%{name}' --rpm-fileattr=Suggests
+%__dlopen_notes_protocol   multifile
+%__dlopen_notes_magic      ^.*ELF (32|64)-bit.*$