summaryrefslogtreecommitdiffstats
path: root/baseudev.py
blob: f441bceaa237f5dd83579b9a42ce8638b310bd44 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
# udev.py
# Python module for querying the udev database for device information.
#
# Copyright (C) 2009  Red Hat, Inc.
#
# This copyrighted material is made available to anyone wishing to use,
# modify, copy, or redistribute it subject to the terms and conditions of
# the GNU General Public License v.2, or (at your option) any later version.
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY expressed or implied, including the implied warranties of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General
# Public License for more details.  You should have received a copy of the
# GNU General Public License along with this program; if not, write to the
# Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
# 02110-1301, USA.  Any Red Hat trademarks that are incorporated in the
# source code or documentation are not subject to the GNU General Public
# License and may only be used or replicated with the express permission of
# Red Hat, Inc.
#
# Red Hat Author(s): Dave Lehman <dlehman@redhat.com>
#                    Chris Lumens <clumens@redhat.com>
#

import iutil
import os

import logging
log = logging.getLogger("storage")

def udev_enumerate_devices(deviceClass="block"):
    top_dir = "/sys/class/%s" % deviceClass
    devices = []
    for dev_name in os.listdir(top_dir):
        full_path = os.path.join(top_dir, dev_name)
        link_ref = os.readlink(full_path)
        real_path = os.path.join(top_dir, link_ref)
        sysfs_path = os.path.normpath(real_path)
        devices.append(sysfs_path)
    return devices

def udev_get_device(sysfs_path):
    if not os.path.exists(sysfs_path):
        log.debug("%s does not exist" % sysfs_path)
        return None

    db_entry = sysfs_path[4:].replace("/", "\\x2f")
    db_root = "/dev/.udev/db"
    db_path = os.path.normpath("%s/%s" % (db_root, db_entry))
    if not os.access(db_path, os.R_OK):
        log.debug("db entry %s does not exist" % db_path)
        return None

    entry = open(db_path).read()
    dev = udev_parse_entry(entry)
    if dev.has_key("name"):
        # XXX why do we do this? is /sys going to move during installation?
        dev['sysfs_path'] = sysfs_path[4:]  # strip off the leading '/sys'
        dev = udev_parse_uevent_file(dev)

    # now add in the contents of the uevent file since they're handy
    return dev

def udev_get_devices(deviceClass="block"):
    udev_settle(timeout=30)
    entries = []
    for path in udev_enumerate_devices(deviceClass):
        entry = udev_get_device(path)
        if entry:
            entries.append(entry)
    return entries

def udev_parse_entry(buf):
    dev = {}

    for line in buf.splitlines():
        line.strip()
        (tag, sep, val) = line.partition(":")
        if not sep:
            continue

        if tag == "N":
            dev['name'] = val
        elif tag == "S":
            if dev.has_key('symlinks'):
                dev['symlinks'].append(val)
            else:
                dev['symlinks'] = [val]
        elif tag == "E":
            if val.count("=") > 1 and val.count(" ") > 0:
                # eg: LVM2_LV_NAME when querying the VG for its LVs
                vars = val.split()
                vals = []
                var_name = None
                for (index, subval) in enumerate(vars):
                    (var_name, sep, var_val) = subval.partition("=")
                    if sep:
                        vals.append(var_val)

                dev[var_name] = vals
            else:
                (var_name, sep, var_val) = val.partition("=")
                if not sep:
                    continue

                dev[var_name] = var_val

    return dev

def udev_parse_uevent_file(dev):
    path = os.path.normpath("/sys/%s/uevent" % dev['sysfs_path'])
    if not os.access(path, os.R_OK):
        return dev

    with open(path) as f:
        for line in f.readlines():
            (key, equals, value) = line.strip().partition("=")
            if not equals:
                continue

            dev[key] = value

    return dev

def udev_settle(timeout=None):
    argv = ["settle"]
    if timeout:
        argv.append("--timeout=%d" % int(timeout))

    iutil.execWithRedirect("udevadm", argv, stderr="/dev/null", searchPath=1)

def udev_trigger(subsystem=None):
    argv = ["trigger"]
    if subsystem:
        argv.append("--subsystem-match=%s" % subsystem)

    iutil.execWithRedirect("udevadm", argv, stderr="/dev/null", searchPath=1)