1"""
2   class for handling configuration data files
3
4   Reads a .conf file and obtains its metadata
5
6"""
7
8# Copyright (C) 2003, 2004  Chris Larson
9# Copyright (C) 2003, 2004  Phil Blundell
10#
11# SPDX-License-Identifier: GPL-2.0-only
12#
13
14import errno
15import re
16import os
17import bb.utils
18from bb.parse import ParseError, resolve_file, ast, logger, handle
19
20__config_regexp__  = re.compile( r"""
21    ^
22    (?P<exp>export\s+)?
23    (?P<var>[a-zA-Z0-9\-_+.${}/~:]+?)
24    (\[(?P<flag>[a-zA-Z0-9\-_+.]+)\])?
25
26    \s* (
27        (?P<colon>:=) |
28        (?P<lazyques>\?\?=) |
29        (?P<ques>\?=) |
30        (?P<append>\+=) |
31        (?P<prepend>=\+) |
32        (?P<predot>=\.) |
33        (?P<postdot>\.=) |
34        =
35    ) \s*
36
37    (?!'[^']*'[^']*'$)
38    (?!\"[^\"]*\"[^\"]*\"$)
39    (?P<apo>['\"])
40    (?P<value>.*)
41    (?P=apo)
42    $
43    """, re.X)
44__include_regexp__ = re.compile( r"include\s+(.+)" )
45__require_regexp__ = re.compile( r"require\s+(.+)" )
46__export_regexp__ = re.compile( r"export\s+([a-zA-Z0-9\-_+.${}/~]+)$" )
47__unset_regexp__ = re.compile( r"unset\s+([a-zA-Z0-9\-_+.${}/~]+)$" )
48__unset_flag_regexp__ = re.compile( r"unset\s+([a-zA-Z0-9\-_+.${}/~]+)\[([a-zA-Z0-9\-_+.]+)\]$" )
49
50def init(data):
51    return
52
53def supports(fn, d):
54    return fn[-5:] == ".conf"
55
56def include(parentfn, fns, lineno, data, error_out):
57    """
58    error_out: A string indicating the verb (e.g. "include", "inherit") to be
59    used in a ParseError that will be raised if the file to be included could
60    not be included. Specify False to avoid raising an error in this case.
61    """
62    fns = data.expand(fns)
63    parentfn = data.expand(parentfn)
64
65    # "include" or "require" accept zero to n space-separated file names to include.
66    for fn in fns.split():
67        include_single_file(parentfn, fn, lineno, data, error_out)
68
69def include_single_file(parentfn, fn, lineno, data, error_out):
70    """
71    Helper function for include() which does not expand or split its parameters.
72    """
73    if parentfn == fn: # prevent infinite recursion
74        return None
75
76    if not os.path.isabs(fn):
77        dname = os.path.dirname(parentfn)
78        bbpath = "%s:%s" % (dname, data.getVar("BBPATH"))
79        abs_fn, attempts = bb.utils.which(bbpath, fn, history=True)
80        if abs_fn and bb.parse.check_dependency(data, abs_fn):
81            logger.warning("Duplicate inclusion for %s in %s" % (abs_fn, data.getVar('FILE')))
82        for af in attempts:
83            bb.parse.mark_dependency(data, af)
84        if abs_fn:
85            fn = abs_fn
86    elif bb.parse.check_dependency(data, fn):
87        logger.warning("Duplicate inclusion for %s in %s" % (fn, data.getVar('FILE')))
88
89    try:
90        bb.parse.handle(fn, data, True)
91    except (IOError, OSError) as exc:
92        if exc.errno == errno.ENOENT:
93            if error_out:
94                raise ParseError("Could not %s file %s" % (error_out, fn), parentfn, lineno)
95            logger.debug2("CONF file '%s' not found", fn)
96        else:
97            if error_out:
98                raise ParseError("Could not %s file %s: %s" % (error_out, fn, exc.strerror), parentfn, lineno)
99            else:
100                raise ParseError("Error parsing %s: %s" % (fn, exc.strerror), parentfn, lineno)
101
102# We have an issue where a UI might want to enforce particular settings such as
103# an empty DISTRO variable. If configuration files do something like assigning
104# a weak default, it turns out to be very difficult to filter out these changes,
105# particularly when the weak default might appear half way though parsing a chain
106# of configuration files. We therefore let the UIs hook into configuration file
107# parsing. This turns out to be a hard problem to solve any other way.
108confFilters = []
109
110def handle(fn, data, include):
111    init(data)
112
113    if include == 0:
114        oldfile = None
115    else:
116        oldfile = data.getVar('FILE', False)
117
118    abs_fn = resolve_file(fn, data)
119    with open(abs_fn, 'r') as f:
120
121        statements = ast.StatementGroup()
122        lineno = 0
123        while True:
124            lineno = lineno + 1
125            s = f.readline()
126            if not s:
127                break
128            origlineno = lineno
129            origline = s
130            w = s.strip()
131            # skip empty lines
132            if not w:
133                continue
134            s = s.rstrip()
135            while s[-1] == '\\':
136                line = f.readline()
137                origline += line
138                s2 = line.rstrip()
139                lineno = lineno + 1
140                if (not s2 or s2 and s2[0] != "#") and s[0] == "#" :
141                    bb.fatal("There is a confusing multiline, partially commented expression starting on line %s of file %s:\n%s\nPlease clarify whether this is all a comment or should be parsed." % (origlineno, fn, origline))
142
143                s = s[:-1] + s2
144            # skip comments
145            if s[0] == '#':
146                continue
147            feeder(lineno, s, abs_fn, statements)
148
149    # DONE WITH PARSING... time to evaluate
150    data.setVar('FILE', abs_fn)
151    statements.eval(data)
152    if oldfile:
153        data.setVar('FILE', oldfile)
154
155    for f in confFilters:
156        f(fn, data)
157
158    return data
159
160def feeder(lineno, s, fn, statements):
161    m = __config_regexp__.match(s)
162    if m:
163        groupd = m.groupdict()
164        ast.handleData(statements, fn, lineno, groupd)
165        return
166
167    m = __include_regexp__.match(s)
168    if m:
169        ast.handleInclude(statements, fn, lineno, m, False)
170        return
171
172    m = __require_regexp__.match(s)
173    if m:
174        ast.handleInclude(statements, fn, lineno, m, True)
175        return
176
177    m = __export_regexp__.match(s)
178    if m:
179        ast.handleExport(statements, fn, lineno, m)
180        return
181
182    m = __unset_regexp__.match(s)
183    if m:
184        ast.handleUnset(statements, fn, lineno, m)
185        return
186
187    m = __unset_flag_regexp__.match(s)
188    if m:
189        ast.handleUnsetFlag(statements, fn, lineno, m)
190        return
191
192    raise ParseError("unparsed line: '%s'" % s, fn, lineno);
193
194# Add us to the handlers list
195from bb.parse import handlers
196handlers.append({'supports': supports, 'handle': handle, 'init': init})
197del handlers
198