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Andrew Geisslerb7d28612020-07-24 16:15:54 -05001#
Patrick Williams92b42cb2022-09-03 06:53:57 -05002# Copyright OpenEmbedded Contributors
3#
Andrew Geisslerb7d28612020-07-24 16:15:54 -05004# SPDX-License-Identifier: GPL-2.0-only
5#
6import os
7import subprocess
8import bb
9
Andrew Geisslereff27472021-10-29 15:35:00 -050010# For reproducible builds, this code sets the default SOURCE_DATE_EPOCH in each
11# component's build environment. The format is number of seconds since the
12# system epoch.
13#
14# Upstream components (generally) respect this environment variable,
15# using it in place of the "current" date and time.
16# See https://reproducible-builds.org/specs/source-date-epoch/
17#
18# The default value of SOURCE_DATE_EPOCH comes from the function
19# get_source_date_epoch_value which reads from the SDE_FILE, or if the file
20# is not available will use the fallback of SOURCE_DATE_EPOCH_FALLBACK.
21#
22# The SDE_FILE is normally constructed from the function
23# create_source_date_epoch_stamp which is typically added as a postfuncs to
24# the do_unpack task. If a recipe does NOT have do_unpack, it should be added
25# to a task that runs after the source is available and before the
26# do_deploy_source_date_epoch task is executed.
27#
28# If a recipe wishes to override the default behavior it should set it's own
29# SOURCE_DATE_EPOCH or override the do_deploy_source_date_epoch_stamp task
30# with recipe-specific functionality to write the appropriate
31# SOURCE_DATE_EPOCH into the SDE_FILE.
32#
33# SOURCE_DATE_EPOCH is intended to be a reproducible value. This value should
34# be reproducible for anyone who builds the same revision from the same
35# sources.
36#
37# There are 4 ways the create_source_date_epoch_stamp function determines what
38# becomes SOURCE_DATE_EPOCH:
39#
40# 1. Use the value from __source_date_epoch.txt file if this file exists.
41# This file was most likely created in the previous build by one of the
42# following methods 2,3,4.
43# Alternatively, it can be provided by a recipe via SRC_URI.
44#
45# If the file does not exist:
46#
47# 2. If there is a git checkout, use the last git commit timestamp.
48# Git does not preserve file timestamps on checkout.
49#
50# 3. Use the mtime of "known" files such as NEWS, CHANGLELOG, ...
51# This works for well-kept repositories distributed via tarball.
52#
53# 4. Use the modification time of the youngest file in the source tree, if
54# there is one.
55# This will be the newest file from the distribution tarball, if any.
56#
57# 5. Fall back to a fixed timestamp (SOURCE_DATE_EPOCH_FALLBACK).
58#
59# Once the value is determined, it is stored in the recipe's SDE_FILE.
60
Andrew Geisslerb7d28612020-07-24 16:15:54 -050061def get_source_date_epoch_from_known_files(d, sourcedir):
62 source_date_epoch = None
63 newest_file = None
64 known_files = set(["NEWS", "ChangeLog", "Changelog", "CHANGES"])
65 for file in known_files:
66 filepath = os.path.join(sourcedir, file)
67 if os.path.isfile(filepath):
68 mtime = int(os.lstat(filepath).st_mtime)
69 # There may be more than one "known_file" present, if so, use the youngest one
70 if not source_date_epoch or mtime > source_date_epoch:
71 source_date_epoch = mtime
72 newest_file = filepath
73 if newest_file:
74 bb.debug(1, "SOURCE_DATE_EPOCH taken from: %s" % newest_file)
75 return source_date_epoch
76
77def find_git_folder(d, sourcedir):
78 # First guess: WORKDIR/git
79 # This is the default git fetcher unpack path
80 workdir = d.getVar('WORKDIR')
81 gitpath = os.path.join(workdir, "git/.git")
82 if os.path.isdir(gitpath):
83 return gitpath
84
85 # Second guess: ${S}
86 gitpath = os.path.join(sourcedir, ".git")
87 if os.path.isdir(gitpath):
88 return gitpath
89
90 # Perhaps there was a subpath or destsuffix specified.
91 # Go looking in the WORKDIR
92 exclude = set(["build", "image", "license-destdir", "patches", "pseudo",
93 "recipe-sysroot", "recipe-sysroot-native", "sysroot-destdir", "temp"])
94 for root, dirs, files in os.walk(workdir, topdown=True):
95 dirs[:] = [d for d in dirs if d not in exclude]
96 if '.git' in dirs:
Andrew Geissler595f6302022-01-24 19:11:47 +000097 return os.path.join(root, ".git")
Andrew Geisslerb7d28612020-07-24 16:15:54 -050098
99 bb.warn("Failed to find a git repository in WORKDIR: %s" % workdir)
100 return None
101
102def get_source_date_epoch_from_git(d, sourcedir):
Andrew Geissler09209ee2020-12-13 08:44:15 -0600103 if not "git://" in d.getVar('SRC_URI') and not "gitsm://" in d.getVar('SRC_URI'):
Andrew Geisslerb7d28612020-07-24 16:15:54 -0500104 return None
105
106 gitpath = find_git_folder(d, sourcedir)
107 if not gitpath:
108 return None
109
110 # Check that the repository has a valid HEAD; it may not if subdir is used
111 # in SRC_URI
Andrew Geissler635e0e42020-08-21 15:58:33 -0500112 p = subprocess.run(['git', '--git-dir', gitpath, 'rev-parse', 'HEAD'], stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
Andrew Geisslerb7d28612020-07-24 16:15:54 -0500113 if p.returncode != 0:
114 bb.debug(1, "%s does not have a valid HEAD: %s" % (gitpath, p.stdout.decode('utf-8')))
115 return None
116
117 bb.debug(1, "git repository: %s" % gitpath)
Andrew Geisslerc5535c92023-01-27 16:10:19 -0600118 p = subprocess.run(['git', '-c', 'log.showSignature=false', '--git-dir', gitpath, 'log', '-1', '--pretty=%ct'],
119 check=True, stdout=subprocess.PIPE)
Andrew Geisslerb7d28612020-07-24 16:15:54 -0500120 return int(p.stdout.decode('utf-8'))
121
122def get_source_date_epoch_from_youngest_file(d, sourcedir):
123 if sourcedir == d.getVar('WORKDIR'):
124 # These sources are almost certainly not from a tarball
125 return None
126
127 # Do it the hard way: check all files and find the youngest one...
128 source_date_epoch = None
129 newest_file = None
130 for root, dirs, files in os.walk(sourcedir, topdown=True):
131 files = [f for f in files if not f[0] == '.']
132
133 for fname in files:
134 filename = os.path.join(root, fname)
135 try:
136 mtime = int(os.lstat(filename).st_mtime)
137 except ValueError:
138 mtime = 0
139 if not source_date_epoch or mtime > source_date_epoch:
140 source_date_epoch = mtime
141 newest_file = filename
142
143 if newest_file:
144 bb.debug(1, "Newest file found: %s" % newest_file)
145 return source_date_epoch
146
Andrew Geissler90fd73c2021-03-05 15:25:55 -0600147def fixed_source_date_epoch(d):
Andrew Geisslerb7d28612020-07-24 16:15:54 -0500148 bb.debug(1, "No tarball or git repo found to determine SOURCE_DATE_EPOCH")
Andrew Geissler90fd73c2021-03-05 15:25:55 -0600149 source_date_epoch = d.getVar('SOURCE_DATE_EPOCH_FALLBACK')
150 if source_date_epoch:
151 bb.debug(1, "Using SOURCE_DATE_EPOCH_FALLBACK")
152 return int(source_date_epoch)
Andrew Geisslerb7d28612020-07-24 16:15:54 -0500153 return 0
154
155def get_source_date_epoch(d, sourcedir):
156 return (
157 get_source_date_epoch_from_git(d, sourcedir) or
Andrew Geisslerb7d28612020-07-24 16:15:54 -0500158 get_source_date_epoch_from_youngest_file(d, sourcedir) or
Andrew Geissler90fd73c2021-03-05 15:25:55 -0600159 fixed_source_date_epoch(d) # Last resort
Andrew Geisslerb7d28612020-07-24 16:15:54 -0500160 )
161
Andrew Geisslereff27472021-10-29 15:35:00 -0500162def epochfile_read(epochfile, d):
163 cached, efile = d.getVar('__CACHED_SOURCE_DATE_EPOCH') or (None, None)
164 if cached and efile == epochfile:
165 return cached
166
167 if cached and epochfile != efile:
168 bb.debug(1, "Epoch file changed from %s to %s" % (efile, epochfile))
169
170 source_date_epoch = int(d.getVar('SOURCE_DATE_EPOCH_FALLBACK'))
171 try:
172 with open(epochfile, 'r') as f:
173 s = f.read()
174 try:
175 source_date_epoch = int(s)
176 except ValueError:
177 bb.warn("SOURCE_DATE_EPOCH value '%s' is invalid. Reverting to SOURCE_DATE_EPOCH_FALLBACK" % s)
178 source_date_epoch = int(d.getVar('SOURCE_DATE_EPOCH_FALLBACK'))
179 bb.debug(1, "SOURCE_DATE_EPOCH: %d" % source_date_epoch)
180 except FileNotFoundError:
181 bb.debug(1, "Cannot find %s. SOURCE_DATE_EPOCH will default to %d" % (epochfile, source_date_epoch))
182
183 d.setVar('__CACHED_SOURCE_DATE_EPOCH', (str(source_date_epoch), epochfile))
184 return str(source_date_epoch)
185
186def epochfile_write(source_date_epoch, epochfile, d):
187
188 bb.debug(1, "SOURCE_DATE_EPOCH: %d" % source_date_epoch)
189 bb.utils.mkdirhier(os.path.dirname(epochfile))
190
191 tmp_file = "%s.new" % epochfile
192 with open(tmp_file, 'w') as f:
193 f.write(str(source_date_epoch))
194 os.rename(tmp_file, epochfile)