tools/buildman/toolchain.py - u-boot - Git at Google

 # SPDX-License-Identifier: GPL-2.0+
 # Copyright (c) 2012 The Chromium OS Authors.
 #

 import re
 import glob
 from html.parser import HTMLParser
 import os
 import sys
 import tempfile
 import urllib.request, urllib.error, urllib.parse

 from buildman import bsettings
 from u_boot_pylib import command
 from u_boot_pylib import terminal
 from u_boot_pylib import tools

 (PRIORITY_FULL_PREFIX, PRIORITY_PREFIX_GCC, PRIORITY_PREFIX_GCC_PATH,
     PRIORITY_CALC) = list(range(4))

 (VAR_CROSS_COMPILE, VAR_PATH, VAR_ARCH, VAR_MAKE_ARGS) = range(4)

 # Simple class to collect links from a page
 class MyHTMLParser(HTMLParser):
     def __init__(self, arch):
         """Create a new parser

         After the parser runs, self.links will be set to a list of the links
         to .xz archives found in the page, and self.arch_link will be set to
         the one for the given architecture (or None if not found).

         Args:
             arch: Architecture to search for
         """
         HTMLParser.__init__(self)
         self.arch_link = None
         self.links = []
         self.re_arch = re.compile('[-_]%s-' % arch)

     def handle_starttag(self, tag, attrs):
         if tag == 'a':
             for tag, value in attrs:
                 if tag == 'href':
                     if value and value.endswith('.xz'):
                         self.links.append(value)
                         if self.re_arch.search(value):
                             self.arch_link = value


 class Toolchain:
     """A single toolchain

     Public members:
         gcc: Full path to C compiler
         path: Directory path containing C compiler
         cross: Cross compile string, e.g. 'arm-linux-'
         arch: Architecture of toolchain as determined from the first
                 component of the filename. E.g. arm-linux-gcc becomes arm
         priority: Toolchain priority (0=highest, 20=lowest)
         override_toolchain: Toolchain to use for sandbox, overriding the normal
                 one
     """
     def __init__(self, fname, test, verbose=False, priority=PRIORITY_CALC,
                  arch=None, override_toolchain=None):
         """Create a new toolchain object.

         Args:
             fname: Filename of the gcc component
             test: True to run the toolchain to test it
             verbose: True to print out the information
             priority: Priority to use for this toolchain, or PRIORITY_CALC to
                 calculate it
         """
         self.gcc = fname
         self.path = os.path.dirname(fname)
         self.override_toolchain = override_toolchain

         # Find the CROSS_COMPILE prefix to use for U-Boot. For example,
         # 'arm-linux-gnueabihf-gcc' turns into 'arm-linux-gnueabihf-'.
         basename = os.path.basename(fname)
         pos = basename.rfind('-')
         self.cross = basename[:pos + 1] if pos != -1 else ''

         # The architecture is the first part of the name
         pos = self.cross.find('-')
         if arch:
             self.arch = arch
         else:
             self.arch = self.cross[:pos] if pos != -1 else 'sandbox'
         if self.arch == 'sandbox' and override_toolchain:
             self.gcc = override_toolchain

         env = self.MakeEnvironment(False)

         # As a basic sanity check, run the C compiler with --version
         cmd = [fname, '--version']
         if priority == PRIORITY_CALC:
             self.priority = self.GetPriority(fname)
         else:
             self.priority = priority
         if test:
             result = command.run_pipe([cmd], capture=True, env=env,
                                      raise_on_error=False)
             self.ok = result.return_code == 0
             if verbose:
                 print('Tool chain test: ', end=' ')
                 if self.ok:
                     print("OK, arch='%s', priority %d" % (self.arch,
                                                           self.priority))
                 else:
                     print('BAD')
                     print('Command: ', cmd)
                     print(result.stdout)
                     print(result.stderr)
         else:
             self.ok = True

     def GetPriority(self, fname):
         """Return the priority of the toolchain.

         Toolchains are ranked according to their suitability by their
         filename prefix.

         Args:
             fname: Filename of toolchain
         Returns:
             Priority of toolchain, PRIORITY_CALC=highest, 20=lowest.
         """
         priority_list = ['-elf', '-unknown-linux-gnu', '-linux',
             '-none-linux-gnueabi', '-none-linux-gnueabihf', '-uclinux',
             '-none-eabi', '-gentoo-linux-gnu', '-linux-gnueabi',
             '-linux-gnueabihf', '-le-linux', '-uclinux']
         for prio in range(len(priority_list)):
             if priority_list[prio] in fname:
                 return PRIORITY_CALC + prio
         return PRIORITY_CALC + prio

     def GetWrapper(self, show_warning=True):
         """Get toolchain wrapper from the setting file.
         """
         value = ''
         for name, value in bsettings.GetItems('toolchain-wrapper'):
             if not value:
                 print("Warning: Wrapper not found")
         if value:
             value = value + ' '

         return value

     def GetEnvArgs(self, which):
         """Get an environment variable/args value based on the the toolchain

         Args:
             which: VAR_... value to get

         Returns:
             Value of that environment variable or arguments
         """
         if which == VAR_CROSS_COMPILE:
             wrapper = self.GetWrapper()
             base = '' if self.arch == 'sandbox' else self.path
             return wrapper + os.path.join(base, self.cross)
         elif which == VAR_PATH:
             return self.path
         elif which == VAR_ARCH:
             return self.arch
         elif which == VAR_MAKE_ARGS:
             args = self.MakeArgs()
             if args:
                 return ' '.join(args)
             return ''
         else:
             raise ValueError('Unknown arg to GetEnvArgs (%d)' % which)

     def MakeEnvironment(self, full_path):
         """Returns an environment for using the toolchain.

         Thie takes the current environment and adds CROSS_COMPILE so that
         the tool chain will operate correctly. This also disables localized
         output and possibly unicode encoded output of all build tools by
         adding LC_ALL=C.

         Note that os.environb is used to obtain the environment, since in some
         cases the environment many contain non-ASCII characters and we see
         errors like:

           UnicodeEncodeError: 'utf-8' codec can't encode characters in position
              569-570: surrogates not allowed

         Args:
             full_path: Return the full path in CROSS_COMPILE and don't set
                 PATH
         Returns:
             Dict containing the (bytes) environment to use. This is based on the
             current environment, with changes as needed to CROSS_COMPILE, PATH
             and LC_ALL.
         """
         env = dict(os.environb)
         wrapper = self.GetWrapper()

         if self.override_toolchain:
             # We'll use MakeArgs() to provide this
             pass
         elif full_path:
             env[b'CROSS_COMPILE'] = tools.to_bytes(
                 wrapper + os.path.join(self.path, self.cross))
         else:
             env[b'CROSS_COMPILE'] = tools.to_bytes(wrapper + self.cross)
             env[b'PATH'] = tools.to_bytes(self.path) + b':' + env[b'PATH']

         env[b'LC_ALL'] = b'C'

         return env

     def MakeArgs(self):
         """Create the 'make' arguments for a toolchain

         This is only used when the toolchain is being overridden. Since the
         U-Boot Makefile sets CC and HOSTCC explicitly we cannot rely on the
         environment (and MakeEnvironment()) to override these values. This
         function returns the arguments to accomplish this.

         Returns:
             List of arguments to pass to 'make'
         """
         if self.override_toolchain:
             return ['HOSTCC=%s' % self.override_toolchain,
                     'CC=%s' % self.override_toolchain]
         return []


 class Toolchains:
     """Manage a list of toolchains for building U-Boot

     We select one toolchain for each architecture type

     Public members:
         toolchains: Dict of Toolchain objects, keyed by architecture name
         prefixes: Dict of prefixes to check, keyed by architecture. This can
             be a full path and toolchain prefix, for example
             {'x86', 'opt/i386-linux/bin/i386-linux-'}, or the name of
             something on the search path, for example
             {'arm', 'arm-linux-gnueabihf-'}. Wildcards are not supported.
         paths: List of paths to check for toolchains (may contain wildcards)
     """

     def __init__(self, override_toolchain=None):
         self.toolchains = {}
         self.prefixes = {}
         self.paths = []
         self.override_toolchain = override_toolchain
         self._make_flags = dict(bsettings.GetItems('make-flags'))

     def GetPathList(self, show_warning=True):
         """Get a list of available toolchain paths

         Args:
             show_warning: True to show a warning if there are no tool chains.

         Returns:
             List of strings, each a path to a toolchain mentioned in the
             [toolchain] section of the settings file.
         """
         toolchains = bsettings.GetItems('toolchain')
         if show_warning and not toolchains:
             print(("Warning: No tool chains. Please run 'buildman "
                    "--fetch-arch all' to download all available toolchains, or "
                    "add a [toolchain] section to your buildman config file "
                    "%s. See buildman.rst for details" %
                    bsettings.config_fname))

         paths = []
         for name, value in toolchains:
             if '*' in value:
                 paths += glob.glob(value)
             else:
                 paths.append(value)
         return paths

     def GetSettings(self, show_warning=True):
         """Get toolchain settings from the settings file.

         Args:
             show_warning: True to show a warning if there are no tool chains.
         """
         self.prefixes = bsettings.GetItems('toolchain-prefix')
         self.paths += self.GetPathList(show_warning)

     def Add(self, fname, test=True, verbose=False, priority=PRIORITY_CALC,
             arch=None):
         """Add a toolchain to our list

         We select the given toolchain as our preferred one for its
         architecture if it is a higher priority than the others.

         Args:
             fname: Filename of toolchain's gcc driver
             test: True to run the toolchain to test it
             priority: Priority to use for this toolchain
             arch: Toolchain architecture, or None if not known
         """
         toolchain = Toolchain(fname, test, verbose, priority, arch,
                               self.override_toolchain)
         add_it = toolchain.ok
         if toolchain.arch in self.toolchains:
             add_it = (toolchain.priority <
                         self.toolchains[toolchain.arch].priority)
         if add_it:
             self.toolchains[toolchain.arch] = toolchain
         elif verbose:
             print(("Toolchain '%s' at priority %d will be ignored because "
                    "another toolchain for arch '%s' has priority %d" %
                    (toolchain.gcc, toolchain.priority, toolchain.arch,
                     self.toolchains[toolchain.arch].priority)))

     def ScanPath(self, path, verbose):
         """Scan a path for a valid toolchain

         Args:
             path: Path to scan
             verbose: True to print out progress information
         Returns:
             Filename of C compiler if found, else None
         """
         fnames = []
         for subdir in ['.', 'bin', 'usr/bin']:
             dirname = os.path.join(path, subdir)
             if verbose: print("      - looking in '%s'" % dirname)
             for fname in glob.glob(dirname + '/*gcc'):
                 if verbose: print("         - found '%s'" % fname)
                 fnames.append(fname)
         return fnames

     def ScanPathEnv(self, fname):
         """Scan the PATH environment variable for a given filename.

         Args:
             fname: Filename to scan for
         Returns:
             List of matching pathanames, or [] if none
         """
         pathname_list = []
         for path in os.environ["PATH"].split(os.pathsep):
             path = path.strip('"')
             pathname = os.path.join(path, fname)
             if os.path.exists(pathname):
                 pathname_list.append(pathname)
         return pathname_list

     def Scan(self, verbose):
         """Scan for available toolchains and select the best for each arch.

         We look for all the toolchains we can file, figure out the
         architecture for each, and whether it works. Then we select the
         highest priority toolchain for each arch.

         Args:
             verbose: True to print out progress information
         """
         if verbose: print('Scanning for tool chains')
         for name, value in self.prefixes:
             if verbose: print("   - scanning prefix '%s'" % value)
             if os.path.exists(value):
                 self.Add(value, True, verbose, PRIORITY_FULL_PREFIX, name)
                 continue
             fname = value + 'gcc'
             if os.path.exists(fname):
                 self.Add(fname, True, verbose, PRIORITY_PREFIX_GCC, name)
                 continue
             fname_list = self.ScanPathEnv(fname)
             for f in fname_list:
                 self.Add(f, True, verbose, PRIORITY_PREFIX_GCC_PATH, name)
             if not fname_list:
                 raise ValueError("No tool chain found for prefix '%s'" %
                                    value)
         for path in self.paths:
             if verbose: print("   - scanning path '%s'" % path)
             fnames = self.ScanPath(path, verbose)
             for fname in fnames:
                 self.Add(fname, True, verbose)

     def List(self):
         """List out the selected toolchains for each architecture"""
         col = terminal.Color()
         print(col.build(col.BLUE, 'List of available toolchains (%d):' %
                         len(self.toolchains)))
         if len(self.toolchains):
             for key, value in sorted(self.toolchains.items()):
                 print('%-10s: %s' % (key, value.gcc))
         else:
             print('None')

     def Select(self, arch):
         """Returns the toolchain for a given architecture

         Args:
             args: Name of architecture (e.g. 'arm', 'ppc_8xx')

         returns:
             toolchain object, or None if none found
         """
         for tag, value in bsettings.GetItems('toolchain-alias'):
             if arch == tag:
                 for alias in value.split():
                     if alias in self.toolchains:
                         return self.toolchains[alias]

         if not arch in self.toolchains:
             raise ValueError("No tool chain found for arch '%s'" % arch)
         return self.toolchains[arch]

     def ResolveReferences(self, var_dict, args):
         """Resolve variable references in a string

         This converts ${blah} within the string to the value of blah.
         This function works recursively.

         Args:
             var_dict: Dictionary containing variables and their values
             args: String containing make arguments
         Returns:
             Resolved string

         >>> bsettings.Setup(None)
         >>> tcs = Toolchains()
         >>> tcs.Add('fred', False)
         >>> var_dict = {'oblique' : 'OBLIQUE', 'first' : 'fi${second}rst', \
                         'second' : '2nd'}
         >>> tcs.ResolveReferences(var_dict, 'this=${oblique}_set')
         'this=OBLIQUE_set'
         >>> tcs.ResolveReferences(var_dict, 'this=${oblique}_set${first}nd')
         'this=OBLIQUE_setfi2ndrstnd'
         """
         re_var = re.compile('(\$\{[-_a-z0-9A-Z]{1,}\})')

         while True:
             m = re_var.search(args)
             if not m:
                 break
             lookup = m.group(0)[2:-1]
             value = var_dict.get(lookup, '')
             args = args[:m.start(0)] + value + args[m.end(0):]
         return args

     def GetMakeArguments(self, brd):
         """Returns 'make' arguments for a given board

         The flags are in a section called 'make-flags'. Flags are named
         after the target they represent, for example snapper9260=TESTING=1
         will pass TESTING=1 to make when building the snapper9260 board.

         References to other boards can be added in the string also. For
         example:

         [make-flags]
         at91-boards=ENABLE_AT91_TEST=1
         snapper9260=${at91-boards} BUILD_TAG=442
         snapper9g45=${at91-boards} BUILD_TAG=443

         This will return 'ENABLE_AT91_TEST=1 BUILD_TAG=442' for snapper9260
         and 'ENABLE_AT91_TEST=1 BUILD_TAG=443' for snapper9g45.

         A special 'target' variable is set to the board target.

         Args:
             brd: Board object for the board to check.
         Returns:
             'make' flags for that board, or '' if none
         """
         self._make_flags['target'] = brd.target
         arg_str = self.ResolveReferences(self._make_flags,
                            self._make_flags.get(brd.target, ''))
         args = re.findall("(?:\".*?\"|\S)+", arg_str)
         i = 0
         while i < len(args):
             args[i] = args[i].replace('"', '')
             if not args[i]:
                 del args[i]
             else:
                 i += 1
         return args

     def LocateArchUrl(self, fetch_arch):
         """Find a toolchain available online

         Look in standard places for available toolchains. At present the
         only standard place is at kernel.org.

         Args:
             arch: Architecture to look for, or 'list' for all
         Returns:
             If fetch_arch is 'list', a tuple:
                 Machine architecture (e.g. x86_64)
                 List of toolchains
             else
                 URL containing this toolchain, if avaialble, else None
         """
         arch = command.output_one_line('uname', '-m')
         if arch == 'aarch64':
             arch = 'arm64'
         base = 'https://www.kernel.org/pub/tools/crosstool/files/bin'
         versions = ['12.2.0', '11.1.0']
         links = []
         for version in versions:
             url = '%s/%s/%s/' % (base, arch, version)
             print('Checking: %s' % url)
             response = urllib.request.urlopen(url)
             html = tools.to_string(response.read())
             parser = MyHTMLParser(fetch_arch)
             parser.feed(html)
             if fetch_arch == 'list':
                 links += parser.links
             elif parser.arch_link:
                 return url + parser.arch_link
         if fetch_arch == 'list':
             return arch, links
         return None

     def Unpack(self, fname, dest):
         """Unpack a tar file

         Args:
             fname: Filename to unpack
             dest: Destination directory
         Returns:
             Directory name of the first entry in the archive, without the
             trailing /
         """
         stdout = command.output('tar', 'xvfJ', fname, '-C', dest)
         dirs = stdout.splitlines()[1].split('/')[:2]
         return '/'.join(dirs)

     def TestSettingsHasPath(self, path):
         """Check if buildman will find this toolchain

         Returns:
             True if the path is in settings, False if not
         """
         paths = self.GetPathList(False)
         return path in paths

     def ListArchs(self):
         """List architectures with available toolchains to download"""
         host_arch, archives = self.LocateArchUrl('list')
         re_arch = re.compile('[-a-z0-9.]*[-_]([^-]*)-.*')
         arch_set = set()
         for archive in archives:
             # Remove the host architecture from the start
             arch = re_arch.match(archive[len(host_arch):])
             if arch:
                 if arch.group(1) != '2.0' and arch.group(1) != '64':
                     arch_set.add(arch.group(1))
         return sorted(arch_set)

     def FetchAndInstall(self, arch):
         """Fetch and install a new toolchain

         arch:
             Architecture to fetch, or 'list' to list
         """
         # Fist get the URL for this architecture
         col = terminal.Color()
         print(col.build(col.BLUE, "Downloading toolchain for arch '%s'" % arch))
         url = self.LocateArchUrl(arch)
         if not url:
             print(("Cannot find toolchain for arch '%s' - use 'list' to list" %
                    arch))
             return 2
         home = os.environ['HOME']
         dest = os.path.join(home, '.buildman-toolchains')
         if not os.path.exists(dest):
             os.mkdir(dest)

         # Download the tar file for this toolchain and unpack it
         tarfile, tmpdir = tools.download(url, '.buildman')
         if not tarfile:
             return 1
         print(col.build(col.GREEN, 'Unpacking to: %s' % dest), end=' ')
         sys.stdout.flush()
         path = self.Unpack(tarfile, dest)
         os.remove(tarfile)
         os.rmdir(tmpdir)
         print()

         # Check that the toolchain works
         print(col.build(col.GREEN, 'Testing'))
         dirpath = os.path.join(dest, path)
         compiler_fname_list = self.ScanPath(dirpath, True)
         if not compiler_fname_list:
             print('Could not locate C compiler - fetch failed.')
             return 1
         if len(compiler_fname_list) != 1:
             print(col.build(col.RED, 'Warning, ambiguous toolchains: %s' %
                             ', '.join(compiler_fname_list)))
         toolchain = Toolchain(compiler_fname_list[0], True, True)

         # Make sure that it will be found by buildman
         if not self.TestSettingsHasPath(dirpath):
             print(("Adding 'download' to config file '%s'" %
                    bsettings.config_fname))
             bsettings.SetItem('toolchain', 'download', '%s/*/*' % dest)
         return 0
	# SPDX-License-Identifier: GPL-2.0+
	# Copyright (c) 2012 The Chromium OS Authors.
	#

	import re
	import glob
	from html.parser import HTMLParser
	import os
	import sys
	import tempfile
	import urllib.request, urllib.error, urllib.parse

	from buildman import bsettings
	from u_boot_pylib import command
	from u_boot_pylib import terminal
	from u_boot_pylib import tools

	(PRIORITY_FULL_PREFIX, PRIORITY_PREFIX_GCC, PRIORITY_PREFIX_GCC_PATH,
	PRIORITY_CALC) = list(range(4))

	(VAR_CROSS_COMPILE, VAR_PATH, VAR_ARCH, VAR_MAKE_ARGS) = range(4)

	# Simple class to collect links from a page
	class MyHTMLParser(HTMLParser):
	def __init__(self, arch):
	"""Create a new parser

	After the parser runs, self.links will be set to a list of the links
	to .xz archives found in the page, and self.arch_link will be set to
	the one for the given architecture (or None if not found).

	Args:
	arch: Architecture to search for
	"""
	HTMLParser.__init__(self)
	self.arch_link = None
	self.links = []
	self.re_arch = re.compile('[-_]%s-' % arch)

	def handle_starttag(self, tag, attrs):
	if tag == 'a':
	for tag, value in attrs:
	if tag == 'href':
	if value and value.endswith('.xz'):
	self.links.append(value)
	if self.re_arch.search(value):
	self.arch_link = value


	class Toolchain:
	"""A single toolchain

	Public members:
	gcc: Full path to C compiler
	path: Directory path containing C compiler
	cross: Cross compile string, e.g. 'arm-linux-'
	arch: Architecture of toolchain as determined from the first
	component of the filename. E.g. arm-linux-gcc becomes arm
	priority: Toolchain priority (0=highest, 20=lowest)
	override_toolchain: Toolchain to use for sandbox, overriding the normal
	one
	"""
	def __init__(self, fname, test, verbose=False, priority=PRIORITY_CALC,
	arch=None, override_toolchain=None):
	"""Create a new toolchain object.

	Args:
	fname: Filename of the gcc component
	test: True to run the toolchain to test it
	verbose: True to print out the information
	priority: Priority to use for this toolchain, or PRIORITY_CALC to
	calculate it
	"""
	self.gcc = fname
	self.path = os.path.dirname(fname)
	self.override_toolchain = override_toolchain

	# Find the CROSS_COMPILE prefix to use for U-Boot. For example,
	# 'arm-linux-gnueabihf-gcc' turns into 'arm-linux-gnueabihf-'.
	basename = os.path.basename(fname)
	pos = basename.rfind('-')
	self.cross = basename[:pos + 1] if pos != -1 else ''

	# The architecture is the first part of the name
	pos = self.cross.find('-')
	if arch:
	self.arch = arch
	else:
	self.arch = self.cross[:pos] if pos != -1 else 'sandbox'
	if self.arch == 'sandbox' and override_toolchain:
	self.gcc = override_toolchain

	env = self.MakeEnvironment(False)

	# As a basic sanity check, run the C compiler with --version
	cmd = [fname, '--version']
	if priority == PRIORITY_CALC:
	self.priority = self.GetPriority(fname)
	else:
	self.priority = priority
	if test:
	result = command.run_pipe([cmd], capture=True, env=env,
	raise_on_error=False)
	self.ok = result.return_code == 0
	if verbose:
	print('Tool chain test: ', end=' ')
	if self.ok:
	print("OK, arch='%s', priority %d" % (self.arch,
	self.priority))
	else:
	print('BAD')
	print('Command: ', cmd)
	print(result.stdout)
	print(result.stderr)
	else:
	self.ok = True

	def GetPriority(self, fname):
	"""Return the priority of the toolchain.

	Toolchains are ranked according to their suitability by their
	filename prefix.

	Args:
	fname: Filename of toolchain
	Returns:
	Priority of toolchain, PRIORITY_CALC=highest, 20=lowest.
	"""
	priority_list = ['-elf', '-unknown-linux-gnu', '-linux',
	'-none-linux-gnueabi', '-none-linux-gnueabihf', '-uclinux',
	'-none-eabi', '-gentoo-linux-gnu', '-linux-gnueabi',
	'-linux-gnueabihf', '-le-linux', '-uclinux']
	for prio in range(len(priority_list)):
	if priority_list[prio] in fname:
	return PRIORITY_CALC + prio
	return PRIORITY_CALC + prio

	def GetWrapper(self, show_warning=True):
	"""Get toolchain wrapper from the setting file.
	"""
	value = ''
	for name, value in bsettings.GetItems('toolchain-wrapper'):
	if not value:
	print("Warning: Wrapper not found")
	if value:
	value = value + ' '

	return value

	def GetEnvArgs(self, which):
	"""Get an environment variable/args value based on the the toolchain

	Args:
	which: VAR_... value to get

	Returns:
	Value of that environment variable or arguments
	"""
	if which == VAR_CROSS_COMPILE:
	wrapper = self.GetWrapper()
	base = '' if self.arch == 'sandbox' else self.path
	return wrapper + os.path.join(base, self.cross)
	elif which == VAR_PATH:
	return self.path
	elif which == VAR_ARCH:
	return self.arch
	elif which == VAR_MAKE_ARGS:
	args = self.MakeArgs()
	if args:
	return ' '.join(args)
	return ''
	else:
	raise ValueError('Unknown arg to GetEnvArgs (%d)' % which)

	def MakeEnvironment(self, full_path):
	"""Returns an environment for using the toolchain.

	Thie takes the current environment and adds CROSS_COMPILE so that
	the tool chain will operate correctly. This also disables localized
	output and possibly unicode encoded output of all build tools by
	adding LC_ALL=C.

	Note that os.environb is used to obtain the environment, since in some
	cases the environment many contain non-ASCII characters and we see
	errors like:

	UnicodeEncodeError: 'utf-8' codec can't encode characters in position
	569-570: surrogates not allowed

	Args:
	full_path: Return the full path in CROSS_COMPILE and don't set
	PATH
	Returns:
	Dict containing the (bytes) environment to use. This is based on the
	current environment, with changes as needed to CROSS_COMPILE, PATH
	and LC_ALL.
	"""
	env = dict(os.environb)
	wrapper = self.GetWrapper()

	if self.override_toolchain:
	# We'll use MakeArgs() to provide this
	pass
	elif full_path:
	env[b'CROSS_COMPILE'] = tools.to_bytes(
	wrapper + os.path.join(self.path, self.cross))
	else:
	env[b'CROSS_COMPILE'] = tools.to_bytes(wrapper + self.cross)
	env[b'PATH'] = tools.to_bytes(self.path) + b':' + env[b'PATH']

	env[b'LC_ALL'] = b'C'

	return env

	def MakeArgs(self):
	"""Create the 'make' arguments for a toolchain

	This is only used when the toolchain is being overridden. Since the
	U-Boot Makefile sets CC and HOSTCC explicitly we cannot rely on the
	environment (and MakeEnvironment()) to override these values. This
	function returns the arguments to accomplish this.

	Returns:
	List of arguments to pass to 'make'
	"""
	if self.override_toolchain:
	return ['HOSTCC=%s' % self.override_toolchain,
	'CC=%s' % self.override_toolchain]
	return []


	class Toolchains:
	"""Manage a list of toolchains for building U-Boot

	We select one toolchain for each architecture type

	Public members:
	toolchains: Dict of Toolchain objects, keyed by architecture name
	prefixes: Dict of prefixes to check, keyed by architecture. This can
	be a full path and toolchain prefix, for example
	{'x86', 'opt/i386-linux/bin/i386-linux-'}, or the name of
	something on the search path, for example
	{'arm', 'arm-linux-gnueabihf-'}. Wildcards are not supported.
	paths: List of paths to check for toolchains (may contain wildcards)
	"""

	def __init__(self, override_toolchain=None):
	self.toolchains = {}
	self.prefixes = {}
	self.paths = []
	self.override_toolchain = override_toolchain
	self._make_flags = dict(bsettings.GetItems('make-flags'))

	def GetPathList(self, show_warning=True):
	"""Get a list of available toolchain paths

	Args:
	show_warning: True to show a warning if there are no tool chains.

	Returns:
	List of strings, each a path to a toolchain mentioned in the
	[toolchain] section of the settings file.
	"""
	toolchains = bsettings.GetItems('toolchain')
	if show_warning and not toolchains:
	print(("Warning: No tool chains. Please run 'buildman "
	"--fetch-arch all' to download all available toolchains, or "
	"add a [toolchain] section to your buildman config file "
	"%s. See buildman.rst for details" %
	bsettings.config_fname))

	paths = []
	for name, value in toolchains:
	if '*' in value:
	paths += glob.glob(value)
	else:
	paths.append(value)
	return paths

	def GetSettings(self, show_warning=True):
	"""Get toolchain settings from the settings file.

	Args:
	show_warning: True to show a warning if there are no tool chains.
	"""
	self.prefixes = bsettings.GetItems('toolchain-prefix')
	self.paths += self.GetPathList(show_warning)

	def Add(self, fname, test=True, verbose=False, priority=PRIORITY_CALC,
	arch=None):
	"""Add a toolchain to our list

	We select the given toolchain as our preferred one for its
	architecture if it is a higher priority than the others.

	Args:
	fname: Filename of toolchain's gcc driver
	test: True to run the toolchain to test it
	priority: Priority to use for this toolchain
	arch: Toolchain architecture, or None if not known
	"""
	toolchain = Toolchain(fname, test, verbose, priority, arch,
	self.override_toolchain)
	add_it = toolchain.ok
	if toolchain.arch in self.toolchains:
	add_it = (toolchain.priority <
	self.toolchains[toolchain.arch].priority)
	if add_it:
	self.toolchains[toolchain.arch] = toolchain
	elif verbose:
	print(("Toolchain '%s' at priority %d will be ignored because "
	"another toolchain for arch '%s' has priority %d" %
	(toolchain.gcc, toolchain.priority, toolchain.arch,
	self.toolchains[toolchain.arch].priority)))

	def ScanPath(self, path, verbose):
	"""Scan a path for a valid toolchain

	Args:
	path: Path to scan
	verbose: True to print out progress information
	Returns:
	Filename of C compiler if found, else None
	"""
	fnames = []
	for subdir in ['.', 'bin', 'usr/bin']:
	dirname = os.path.join(path, subdir)
	if verbose: print(" - looking in '%s'" % dirname)
	for fname in glob.glob(dirname + '/*gcc'):
	if verbose: print(" - found '%s'" % fname)
	fnames.append(fname)
	return fnames

	def ScanPathEnv(self, fname):
	"""Scan the PATH environment variable for a given filename.

	Args:
	fname: Filename to scan for
	Returns:
	List of matching pathanames, or [] if none
	"""
	pathname_list = []
	for path in os.environ["PATH"].split(os.pathsep):
	path = path.strip('"')
	pathname = os.path.join(path, fname)
	if os.path.exists(pathname):
	pathname_list.append(pathname)
	return pathname_list

	def Scan(self, verbose):
	"""Scan for available toolchains and select the best for each arch.

	We look for all the toolchains we can file, figure out the
	architecture for each, and whether it works. Then we select the
	highest priority toolchain for each arch.

	Args:
	verbose: True to print out progress information
	"""
	if verbose: print('Scanning for tool chains')
	for name, value in self.prefixes:
	if verbose: print(" - scanning prefix '%s'" % value)
	if os.path.exists(value):
	self.Add(value, True, verbose, PRIORITY_FULL_PREFIX, name)
	continue
	fname = value + 'gcc'
	if os.path.exists(fname):
	self.Add(fname, True, verbose, PRIORITY_PREFIX_GCC, name)
	continue
	fname_list = self.ScanPathEnv(fname)
	for f in fname_list:
	self.Add(f, True, verbose, PRIORITY_PREFIX_GCC_PATH, name)
	if not fname_list:
	raise ValueError("No tool chain found for prefix '%s'" %
	value)
	for path in self.paths:
	if verbose: print(" - scanning path '%s'" % path)
	fnames = self.ScanPath(path, verbose)
	for fname in fnames:
	self.Add(fname, True, verbose)

	def List(self):
	"""List out the selected toolchains for each architecture"""
	col = terminal.Color()
	print(col.build(col.BLUE, 'List of available toolchains (%d):' %
	len(self.toolchains)))
	if len(self.toolchains):
	for key, value in sorted(self.toolchains.items()):
	print('%-10s: %s' % (key, value.gcc))
	else:
	print('None')

	def Select(self, arch):
	"""Returns the toolchain for a given architecture

	Args:
	args: Name of architecture (e.g. 'arm', 'ppc_8xx')

	returns:
	toolchain object, or None if none found
	"""
	for tag, value in bsettings.GetItems('toolchain-alias'):
	if arch == tag:
	for alias in value.split():
	if alias in self.toolchains:
	return self.toolchains[alias]

	if not arch in self.toolchains:
	raise ValueError("No tool chain found for arch '%s'" % arch)
	return self.toolchains[arch]

	def ResolveReferences(self, var_dict, args):
	"""Resolve variable references in a string

	This converts ${blah} within the string to the value of blah.
	This function works recursively.

	Args:
	var_dict: Dictionary containing variables and their values
	args: String containing make arguments
	Returns:
	Resolved string

	>>> bsettings.Setup(None)
	>>> tcs = Toolchains()
	>>> tcs.Add('fred', False)
	>>> var_dict = {'oblique' : 'OBLIQUE', 'first' : 'fi${second}rst', \
	'second' : '2nd'}
	>>> tcs.ResolveReferences(var_dict, 'this=${oblique}_set')
	'this=OBLIQUE_set'
	>>> tcs.ResolveReferences(var_dict, 'this=${oblique}_set${first}nd')
	'this=OBLIQUE_setfi2ndrstnd'
	"""
	re_var = re.compile('(\$\{[-_a-z0-9A-Z]{1,}\})')

	while True:
	m = re_var.search(args)
	if not m:
	break
	lookup = m.group(0)[2:-1]
	value = var_dict.get(lookup, '')
	args = args[:m.start(0)] + value + args[m.end(0):]
	return args

	def GetMakeArguments(self, brd):
	"""Returns 'make' arguments for a given board

	The flags are in a section called 'make-flags'. Flags are named
	after the target they represent, for example snapper9260=TESTING=1
	will pass TESTING=1 to make when building the snapper9260 board.

	References to other boards can be added in the string also. For
	example:

	[make-flags]
	at91-boards=ENABLE_AT91_TEST=1
	snapper9260=${at91-boards} BUILD_TAG=442
	snapper9g45=${at91-boards} BUILD_TAG=443

	This will return 'ENABLE_AT91_TEST=1 BUILD_TAG=442' for snapper9260
	and 'ENABLE_AT91_TEST=1 BUILD_TAG=443' for snapper9g45.

	A special 'target' variable is set to the board target.

	Args:
	brd: Board object for the board to check.
	Returns:
	'make' flags for that board, or '' if none
	"""
	self._make_flags['target'] = brd.target
	arg_str = self.ResolveReferences(self._make_flags,
	self._make_flags.get(brd.target, ''))
	args = re.findall("(?:\".*?\"\|\S)+", arg_str)
	i = 0
	while i < len(args):
	args[i] = args[i].replace('"', '')
	if not args[i]:
	del args[i]
	else:
	i += 1
	return args

	def LocateArchUrl(self, fetch_arch):
	"""Find a toolchain available online

	Look in standard places for available toolchains. At present the
	only standard place is at kernel.org.

	Args:
	arch: Architecture to look for, or 'list' for all
	Returns:
	If fetch_arch is 'list', a tuple:
	Machine architecture (e.g. x86_64)
	List of toolchains
	else
	URL containing this toolchain, if avaialble, else None
	"""
	arch = command.output_one_line('uname', '-m')
	if arch == 'aarch64':
	arch = 'arm64'
	base = 'https://www.kernel.org/pub/tools/crosstool/files/bin'
	versions = ['12.2.0', '11.1.0']
	links = []
	for version in versions:
	url = '%s/%s/%s/' % (base, arch, version)
	print('Checking: %s' % url)
	response = urllib.request.urlopen(url)
	html = tools.to_string(response.read())
	parser = MyHTMLParser(fetch_arch)
	parser.feed(html)
	if fetch_arch == 'list':
	links += parser.links
	elif parser.arch_link:
	return url + parser.arch_link
	if fetch_arch == 'list':
	return arch, links
	return None

	def Unpack(self, fname, dest):
	"""Unpack a tar file

	Args:
	fname: Filename to unpack
	dest: Destination directory
	Returns:
	Directory name of the first entry in the archive, without the
	trailing /
	"""
	stdout = command.output('tar', 'xvfJ', fname, '-C', dest)
	dirs = stdout.splitlines()[1].split('/')[:2]
	return '/'.join(dirs)

	def TestSettingsHasPath(self, path):
	"""Check if buildman will find this toolchain

	Returns:
	True if the path is in settings, False if not
	"""
	paths = self.GetPathList(False)
	return path in paths

	def ListArchs(self):
	"""List architectures with available toolchains to download"""
	host_arch, archives = self.LocateArchUrl('list')
	re_arch = re.compile('[-a-z0-9.][-_]([^-])-.*')
	arch_set = set()
	for archive in archives:
	# Remove the host architecture from the start
	arch = re_arch.match(archive[len(host_arch):])
	if arch:
	if arch.group(1) != '2.0' and arch.group(1) != '64':
	arch_set.add(arch.group(1))
	return sorted(arch_set)

	def FetchAndInstall(self, arch):
	"""Fetch and install a new toolchain

	arch:
	Architecture to fetch, or 'list' to list
	"""
	# Fist get the URL for this architecture
	col = terminal.Color()
	print(col.build(col.BLUE, "Downloading toolchain for arch '%s'" % arch))
	url = self.LocateArchUrl(arch)
	if not url:
	print(("Cannot find toolchain for arch '%s' - use 'list' to list" %
	arch))
	return 2
	home = os.environ['HOME']
	dest = os.path.join(home, '.buildman-toolchains')
	if not os.path.exists(dest):
	os.mkdir(dest)

	# Download the tar file for this toolchain and unpack it
	tarfile, tmpdir = tools.download(url, '.buildman')
	if not tarfile:
	return 1
	print(col.build(col.GREEN, 'Unpacking to: %s' % dest), end=' ')
	sys.stdout.flush()
	path = self.Unpack(tarfile, dest)
	os.remove(tarfile)
	os.rmdir(tmpdir)
	print()

	# Check that the toolchain works
	print(col.build(col.GREEN, 'Testing'))
	dirpath = os.path.join(dest, path)
	compiler_fname_list = self.ScanPath(dirpath, True)
	if not compiler_fname_list:
	print('Could not locate C compiler - fetch failed.')
	return 1
	if len(compiler_fname_list) != 1:
	print(col.build(col.RED, 'Warning, ambiguous toolchains: %s' %
	', '.join(compiler_fname_list)))
	toolchain = Toolchain(compiler_fname_list[0], True, True)

	# Make sure that it will be found by buildman
	if not self.TestSettingsHasPath(dirpath):
	print(("Adding 'download' to config file '%s'" %
	bsettings.config_fname))
	bsettings.SetItem('toolchain', 'download', '%s//' % dest)
	return 0