path: root/meta/classes/update-alternatives.bbclass

# This class is used to help the alternatives system which is useful when
# multiple sources provide same command. You can use update-alternatives
# command directly in your recipe, but in most cases this class simplifies
# that job.
#
# To use this class a number of variables should be defined:
#
# List all of the alternatives needed by a package:
# ALTERNATIVE_<pkg> = "name1 name2 name3 ..."
#
#   i.e. ALTERNATIVE_busybox = "sh sed test bracket"
#
# The pathname of the link
# ALTERNATIVE_LINK_NAME[name] = "target"
#
#   This is the name of the binary once it's been installed onto the runtime.
#   This name is global to all split packages in this recipe, and should match
#   other recipes with the same functionality.
#   i.e. ALTERNATIVE_LINK_NAME[bracket] = "/usr/bin/["
#
# NOTE: If ALTERNATIVE_LINK_NAME is not defined, it defaults to ${bindir}/name
#
# The default link to create for all targets
# ALTERNATIVE_TARGET = "target"
#
#   This is useful in a multicall binary case
#   i.e. ALTERNATIVE_TARGET = "/bin/busybox"
#
# A non-default link to create for a target
# ALTERNATIVE_TARGET[name] = "target"
#
#   This is the name of the binary as it's been install by do_install
#   i.e. ALTERNATIVE_TARGET[sh] = "/bin/bash"
#
# A package specific link for a target
# ALTERNATIVE_TARGET_<pkg>[name] = "target"
#
#   This is useful when a recipe provides multiple alternatives for the
#   same item.
#
# NOTE: If ALTERNATIVE_TARGET is not defined, it will inherit the value
# from ALTERNATIVE_LINK_NAME.
#
# NOTE: If the ALTERNATIVE_LINK_NAME and ALTERNATIVE_TARGET are the same,
# ALTERNATIVE_TARGET will have '.{BPN}' appended to it.  If the file
# referenced has not been renamed, it will also be renamed.  (This avoids
# the need to rename alternative files in the do_install step, but still
# supports it if necessary for some reason.)
#
# The default priority for any alternatives
# ALTERNATIVE_PRIORITY = "priority"
#
#   i.e. default is ALTERNATIVE_PRIORITY = "10"
#
# The non-default priority for a specific target
# ALTERNATIVE_PRIORITY[name] = "priority"
#
# The package priority for a specific target
# ALTERNATIVE_PRIORITY_<pkg>[name] = "priority"
#
#
# -----
#
#
# The following describes deprecated behavior, using any of the
# following modes will result in a warning, and eventually an error:
#
# There are two basic modes supported: 'single update' and 'batch update'
#
# 'single update' is used for a single alternative command, and you're
# expected to provide at least below keywords:
#
#     ALTERNATIVE_NAME - the name that the alternative is registered
#     ALTERNATIVE_PATH - the path of installed alternative
#
# ALTERNATIVE_PRIORITY and ALTERNATIVE_LINK are optional which have defaults
# in this class.
#
# 'batch update' is used if you have multiple alternatives to be updated.
# Unlike 'single update', 'batch update' in most times only require two
# parameters:
#
#     ALTERNATIVE_LINKS - a list of symbolic links for which you'd like to
#                         create alternatives, with space as delimiter, e.g:
#
#         ALTERNATIVE_LINKS = "${bindir}/cmd1 ${sbindir}/cmd2 ..."
#
#     ALTERNATIVE_PRIORITY - optional, applies to all
#
# To simplify the design, this class has the assumption that for a name
# listed in ALTERNATIVE_LINKS, say /path/cmd:
#
#     the name of the alternative would be: cmd
#     the path of installed alternative would be: /path/cmd.${BPN}
#     ${D}/path/cmd will be renamed to ${D}/path/cmd.{BPN} automatically
#     priority will be the same from ALTERNATIVE_PRIORITY
#
# If above assumption breaks your requirement, then you still need to use
# your own update-alternatives command directly.

# defaults
ALTERNATIVE_PRIORITY = "10"

# The following code is deprecated, but included for compatibility with older packages
def update_alternatives_after_parse(d):
    if bb.data.inherits_class('native', d) or bb.data.inherits_class('nativesdk', d):
        return

    # The following code is deprecated, but included for compatibility with older packages
    pn = d.getVar('BPN', True)

    if d.getVar('ALTERNATIVE_LINKS') != None:
        # Convert old format to new format...
        alt_links = d.getVar('ALTERNATIVE_LINKS', True) or ""
        for alt_link in alt_links.split():
        	alt_name = os.path.basename(alt_link)

        	alternative = d.getVar('ALTERNATIVE_%s' % pn, True) or ""
        	alternative += " " + alt_name
        	d.setVar('ALTERNATIVE_%s' % pn, alternative)
        	d.setVarFlag('ALTERNATIVE_LINK_NAME', alt_name, alt_link)
        	d.setVarFlag('ALTERNATIVE_TARGET', alt_name, alt_link)
        return

    if d.getVar('ALTERNATIVE_NAME') != None or d.getVar('ALTERNATIVE_PATH') != None:
        # Convert old format to new format...
        alt_name = d.getVar('ALTERNATIVE_NAME', True)
        alt_path = d.getVar('ALTERNATIVE_PATH', True)
        alt_link = d.getVar('ALTERNATIVE_LINK', True) or ("%s/%s" % (d.getVar('bindir', True), alt_name))
        if alt_name == None:
        	raise bb.build.build.FuncFailed, "%s inherits update-alternatives but doesn't set ALTERNATIVE_NAME" % d.getVar('FILE')
        if alt_path == None:
        	raise bb.build.build.FuncFailed, "%s inherits update-alternatives but doesn't set ALTERNATIVE_PATH" % d.getVar('FILE')

        alternative = d.getVar('ALTERNATIVE_%s' % pn, True) or ""
        alternative += " " + alt_name

	# Fix the alt_path if it's relative
	alt_path = os.path.join(os.path.dirname(alt_link), alt_path)

        d.setVar('ALTERNATIVE_%s' % pn, alternative)
        d.setVarFlag('ALTERNATIVE_LINK_NAME', alt_name, alt_link)
        d.setVarFlag('ALTERNATIVE_TARGET', alt_name, alt_path)


# We need special processing for vardeps because it can not work on
# modified flag values.  So we agregate the flags into a new variable
# and include that vairable in the set.

UPDALTVARS  = "ALTERNATIVE ALTERNATIVE_LINK_NAME ALTERNATIVE_TARGET ALTERNATIVE_PRIORITY"

def gen_updatealternativesvardeps(d):
   pkgs = (d.getVar("PACKAGES", True) or "").split()
   vars = (d.getVar("UPDALTVARS", True) or "").split()

   # First compute them for non_pkg versions
   for v in vars:
      for flag in (d.getVarFlags(v) or {}):
         if flag == "doc" or flag == "vardeps" or flag == "vardepsexp":
            continue
         d.appendVar('%s_VARDEPS' % (v), ' %s:%s' % (flag, d.getVarFlag(v, flag, False)))

   for p in pkgs:
      for v in vars:
         for flag in (d.getVarFlags("%s_%s" % (v,p)) or {}):
            if flag == "doc" or flag == "vardeps" or flag == "vardepsexp":
               continue
            d.appendVar('%s_VARDEPS_%s' % (v,p), ' %s:%s' % (flag, d.getVarFlag('%s_%s' % (v,p), flag, False)))

python __anonymous() {
    # deprecated stuff...
    update_alternatives_after_parse(d)

    # compute special vardeps
    gen_updatealternativesvardeps(d)
}

def gen_updatealternativesvars(d):
   ret = []
   pkgs = (d.getVar("PACKAGES", True) or "").split()
   vars = (d.getVar("UPDALTVARS", True) or "").split()

   for v in vars:
      ret.append(v + "_VARDEPS")

   for p in pkgs:
      for v in vars:
         ret.append(v + "_" + p)
         ret.append(v + "_VARDEPS_" + p)
   return " ".join(ret)

# First the deprecated items...
populate_packages[vardeps] += "ALTERNATIVE_LINKS ALTERNATIVE_NAME ALTERNATIVE_PATH"

# Now the new stuff, we use a custom function to generate the right values
populate_packages[vardeps] += "${UPDALTVARS} ${@gen_updatealternativesvars(d)}"

# We need to do the rename after the image creation step, but before
# the split and strip steps..  packagecopy seems to be the earliest reasonable
# place.
python perform_packagecopy_append () {
	# Check for deprecated usage...
	pn = d.getVar('BPN', True)
	if d.getVar('ALTERNATIVE_LINKS', True) != None:
		bb.warn('%s: Use of ALTERNATIVE_LINKS is deprecated, see update-alternatives.bbclass for more info.' % pn)

    	if d.getVar('ALTERNATIVE_NAME', True) != None or d.getVar('ALTERNATIVE_PATH', True) != None:
		bb.warn('%s: Use of ALTERNATIVE_NAME is deprecated, see update-alternatives.bbclass for more info.' % pn)

	# Do actual update alternatives processing
	pkgdest = d.getVar('PKGD', True)
	for pkg in (d.getVar('PACKAGES', True) or "").split():
		# If the src == dest, we know we need to rename the dest by appending ${BPN}
		link_rename = {}
		for alt_name in (d.getVar('ALTERNATIVE_%s' % pkg, True) or "").split():
			alt_link     = d.getVarFlag('ALTERNATIVE_LINK_NAME', alt_name, True)
			if not alt_link:
				alt_link = "%s/%s" % (d.getVar('bindir', True), alt_name)
				d.setVarFlag('ALTERNATIVE_LINK_NAME', alt_name, alt_link)

			alt_target   = d.getVarFlag('ALTERNATIVE_TARGET_%s' % pkg, alt_name, True) or d.getVarFlag('ALTERNATIVE_TARGET', alt_name, True)
			alt_target   = alt_target or d.getVar('ALTERNATIVE_TARGET_%s' % pkg, True) or d.getVar('ALTERNATIVE_TARGET', True) or alt_link
			# Sometimes alt_target is specified as relative to the link name.
			alt_target   = os.path.join(os.path.dirname(alt_link), alt_target)

			# If the link and target are the same name, we need to rename the target.
			if alt_link == alt_target:
				src = '%s/%s' % (pkgdest, alt_target)
				alt_target_rename = '%s.%s' % (alt_target, pn)
				dest = '%s/%s' % (pkgdest, alt_target_rename)
				if os.path.lexists(dest):
					bb.note('%s: Already renamed: %s' % (pn, alt_target_rename))
				elif os.path.lexists(src):
					if os.path.islink(src):
						# Delay rename of links
						link_rename[alt_target] = alt_target_rename
					else:
						bb.note('%s: Rename %s -> %s' % (pn, alt_target, alt_target_rename))
						os.rename(src, dest)
				else:
					bb.warn("%s: alternative target (%s or %s) does not exist, skipping..." % (pn, alt_target, alt_target_rename))
					continue
				d.setVarFlag('ALTERNATIVE_TARGET_%s' % pkg, alt_name, alt_target_rename)

		# Process delayed link names
		# Do these after other renames so we can correct broken links
		for alt_target in link_rename:
			src = '%s/%s' % (pkgdest, alt_target)
			dest = '%s/%s' % (pkgdest, link_rename[alt_target])
			link_target = os.path.join(os.path.dirname(src), os.readlink(src))

			if os.path.lexists(link_target):
				# Ok, the link_target exists, we can rename
				bb.note('%s: Rename (link) %s -> %s' % (pn, alt_target, link_rename[alt_target]))
				os.rename(src, dest)
			else:
				# Try to resolve the broken link to link.${BPN}
				link_maybe = '%s.%s' % (os.readlink(src), pn)
				if os.path.lexists(os.path.join(os.path.dirname(src), link_maybe)):
					# Ok, the renamed link target exists.. create a new link, and remove the original
					bb.note('%s: Creating new link %s -> %s' % (pn, link_rename[alt_target], link_maybe))
					os.symlink(link_maybe, dest)
					os.unlink(src)
				else:
					bb.warn('%s: Unable to resolve dangling symlink: %s' % (pn, alt_target))
}

python populate_packages_prepend () {
	pn = d.getVar('BPN', True)

	# Do actual update alternatives processing
	pkgdest = d.getVar('PKGD', True)
	for pkg in (d.getVar('PACKAGES', True) or "").split():
		# Create post install/removal scripts
		alt_setup_links = ""
		alt_remove_links = ""
		for alt_name in (d.getVar('ALTERNATIVE_%s' % pkg, True) or "").split():
			alt_link     = d.getVarFlag('ALTERNATIVE_LINK_NAME', alt_name, True)
			alt_target   = d.getVarFlag('ALTERNATIVE_TARGET_%s' % pkg, alt_name, True) or d.getVarFlag('ALTERNATIVE_TARGET', alt_name, True)
			alt_target   = alt_target or d.getVar('ALTERNATIVE_TARGET_%s' % pkg, True) or d.getVar('ALTERNATIVE_TARGET', True) or alt_link
			# Sometimes alt_target is specified as relative to the link name.
			alt_target   = os.path.join(os.path.dirname(alt_link), alt_target)

			alt_priority = d.getVarFlag('ALTERNATIVE_PRIORITY_%s' % pkg,  alt_name, True) or d.getVarFlag('ALTERNATIVE_PRIORITY',  alt_name, True)
			alt_priority = alt_priority or d.getVar('ALTERNATIVE_PRIORITY_%s' % pkg, True) or d.getVar('ALTERNATIVE_PRIORITY', True)

			# This shouldn't trigger, as it should have been resolved earlier!
			if alt_link == alt_target:
				bb.note('alt_link == alt_target: %s == %s -- correcting, this should not happen!' % (alt_link, alt_target))
				alt_target = '%s.%s' % (alt_target, pn)

			if not os.path.lexists('%s/%s' % (pkgdest, alt_target)):
				bb.warn('%s: NOT adding alternative provide %s: %s does not exist' % (pn, alt_link, alt_target))
				continue

			# Default to generate shell script.. eventually we may want to change this...
			alt_target = os.path.relpath(alt_target, os.path.dirname(alt_link))

			alt_setup_links  += '	update-alternatives --install %s %s %s %s\n' % (alt_link, alt_name, alt_target, alt_priority)
			alt_remove_links += '	update-alternatives --remove  %s %s\n' % (alt_name, alt_target)

		if alt_setup_links:
			bb.note('adding update-alternatives calls to postinst/postrm for %s' % pkg)
			bb.note('%s' % alt_setup_links)
			postinst = (d.getVar('pkg_postinst_%s' % pkg, True) or d.getVar('pkg_postinst', True)) or '#!/bin/sh\n'
			postinst += alt_setup_links
			d.setVar('pkg_postinst_%s' % pkg, postinst)

			bb.note('%s' % alt_remove_links)
			postrm = (d.getVar('pkg_postrm_%s' % pkg, True) or d.getVar('pkg_postrm', True)) or '#!/bin/sh\n'
			postrm += alt_remove_links
			d.setVar('pkg_postrm_%s' % pkg, postrm)
}

python package_do_filedeps_append () {
	pn = d.getVar('BPN', True)
	pkgdest = d.getVar('PKGDEST', True)

	for pkg in packages.split():
		for alt_name in (d.getVar('ALTERNATIVE_%s' % pkg, True) or "").split():
			alt_link     = d.getVarFlag('ALTERNATIVE_LINK_NAME', alt_name, True)
			alt_target   = d.getVarFlag('ALTERNATIVE_TARGET_%s' % pkg, alt_name, True) or d.getVarFlag('ALTERNATIVE_TARGET', alt_name, True)
			alt_target   = alt_target or d.getVar('ALTERNATIVE_TARGET_%s' % pkg, True) or d.getVar('ALTERNATIVE_TARGET', True) or alt_link

			if alt_link == alt_target:
				bb.warn('alt_link == alt_target: %s == %s' % (alt_link, alt_target))
				alt_target = '%s.%s' % (alt_target, pn)

			if not os.path.lexists('%s/%s/%s' % (pkgdest, pkg, alt_target)):
				continue

			# Add file provide
			trans_target = file_translate(alt_target)
			d.appendVar('FILERPROVIDES_%s_%s' % (trans_target, pkg), " " + alt_link)
			if not trans_target in (d.getVar('FILERPROVIDESFLIST_%s' % pkg, True) or ""):
				d.appendVar('FILERPROVIDESFLIST_%s' % pkg, " " + trans_target)
}