[thirdparty/systemd.git] / man / 90-rearrange-path.py

#!/usr/bin/env python3
# SPDX-License-Identifier: MIT-0

"""

Proof-of-concept systemd environment generator that makes sure that bin dirs
are always after matching sbin dirs in the path.
(Changes /sbin:/bin:/foo/bar to /bin:/sbin:/foo/bar.)

This generator shows how to override the configuration possibly created by
earlier generators. It would be easier to write in bash, but let's have it
in Python just to prove that we can, and to serve as a template for more
interesting generators.

"""

import os
import pathlib

def rearrange_bin_sbin(path):
    """Make sure any pair of …/bin, …/sbin directories is in this order

    >>> rearrange_bin_sbin('/bin:/sbin:/usr/sbin:/usr/bin')
    '/bin:/sbin:/usr/bin:/usr/sbin'
    """
    items = [pathlib.Path(p) for p in path.split(':')]
    for i in range(len(items)):
        if 'sbin' in items[i].parts:
            ind = items[i].parts.index('sbin')
            bin = pathlib.Path(*items[i].parts[:ind], 'bin', *items[i].parts[ind+1:])
            if bin in items[i+1:]:
                j = i + 1 + items[i+1:].index(bin)
                items[i], items[j] = items[j], items[i]
    return ':'.join(p.as_posix() for p in items)

if __name__ == '__main__':
    path = os.environ['PATH'] # This should be always set.
                              # If it's not, we'll just crash, which is OK too.
    new = rearrange_bin_sbin(path)
    if new != path:
        print('PATH={}'.format(new))
Commit	Line	Data
3e67e5c9	1	#!/usr/bin/env python3
1fe6d37e	2	# SPDX-License-Identifier: MIT-0
1bd2d4e3 ZJS	3
	4	"""
	5
	6	Proof-of-concept systemd environment generator that makes sure that bin dirs
	7	are always after matching sbin dirs in the path.
	8	(Changes /sbin:/bin:/foo/bar to /bin:/sbin:/foo/bar.)
	9
	10	This generator shows how to override the configuration possibly created by
	11	earlier generators. It would be easier to write in bash, but let's have it
	12	in Python just to prove that we can, and to serve as a template for more
	13	interesting generators.
	14
	15	"""
	16
	17	import os
	18	import pathlib
	19
	20	def rearrange_bin_sbin(path):
	21	"""Make sure any pair of …/bin, …/sbin directories is in this order
	22
	23	>>> rearrange_bin_sbin('/bin:/sbin:/usr/sbin:/usr/bin')
	24	'/bin:/sbin:/usr/bin:/usr/sbin'
	25	"""
	26	items = [pathlib.Path(p) for p in path.split(':')]
	27	for i in range(len(items)):
	28	if 'sbin' in items[i].parts:
	29	ind = items[i].parts.index('sbin')
	30	bin = pathlib.Path(items[i].parts[:ind], 'bin', items[i].parts[ind+1:])
	31	if bin in items[i+1:]:
	32	j = i + 1 + items[i+1:].index(bin)
	33	items[i], items[j] = items[j], items[i]
	34	return ':'.join(p.as_posix() for p in items)
	35
	36	if __name__ == '__main__':
	37	path = os.environ['PATH'] # This should be always set.
8a2f7b7c	38	# If it's not, we'll just crash, which is OK too.
1bd2d4e3 ZJS	39	new = rearrange_bin_sbin(path)
	40	if new != path:
	41	print('PATH={}'.format(new))