1#!/usr/bin/env python
2"""
3   class for handling configuration data files
4
5   Reads a .conf file and obtains its metadata
6
7"""
8
9# Copyright (C) 2003, 2004  Chris Larson
10# Copyright (C) 2003, 2004  Phil Blundell
11#
12# SPDX-License-Identifier: GPL-2.0-only
13#
14
15import errno
16import re
17import os
18import bb.utils
19from bb.parse import ParseError, resolve_file, ast, logger, handle
20
21__config_regexp__  = re.compile( r"""
22    ^
23    (?P<exp>export\s+)?
24    (?P<var>[a-zA-Z0-9\-_+.${}/~]+?)
25    (\[(?P<flag>[a-zA-Z0-9\-_+.]+)\])?
26
27    \s* (
28        (?P<colon>:=) |
29        (?P<lazyques>\?\?=) |
30        (?P<ques>\?=) |
31        (?P<append>\+=) |
32        (?P<prepend>=\+) |
33        (?P<predot>=\.) |
34        (?P<postdot>\.=) |
35        =
36    ) \s*
37
38    (?!'[^']*'[^']*'$)
39    (?!\"[^\"]*\"[^\"]*\"$)
40    (?P<apo>['\"])
41    (?P<value>.*)
42    (?P=apo)
43    $
44    """, re.X)
45__include_regexp__ = re.compile( r"include\s+(.+)" )
46__require_regexp__ = re.compile( r"require\s+(.+)" )
47__export_regexp__ = re.compile( r"export\s+([a-zA-Z0-9\-_+.${}/~]+)$" )
48__unset_regexp__ = re.compile( r"unset\s+([a-zA-Z0-9\-_+.${}/~]+)$" )
49__unset_flag_regexp__ = re.compile( r"unset\s+([a-zA-Z0-9\-_+.${}/~]+)\[([a-zA-Z0-9\-_+.]+)\]$" )
50
51def init(data):
52    topdir = data.getVar('TOPDIR', False)
53    if not topdir:
54        data.setVar('TOPDIR', os.getcwd())
55
56
57def supports(fn, d):
58    return fn[-5:] == ".conf"
59
60def include(parentfn, fns, lineno, data, error_out):
61    """
62    error_out: A string indicating the verb (e.g. "include", "inherit") to be
63    used in a ParseError that will be raised if the file to be included could
64    not be included. Specify False to avoid raising an error in this case.
65    """
66    fns = data.expand(fns)
67    parentfn = data.expand(parentfn)
68
69    # "include" or "require" accept zero to n space-separated file names to include.
70    for fn in fns.split():
71        include_single_file(parentfn, fn, lineno, data, error_out)
72
73def include_single_file(parentfn, fn, lineno, data, error_out):
74    """
75    Helper function for include() which does not expand or split its parameters.
76    """
77    if parentfn == fn: # prevent infinite recursion
78        return None
79
80    if not os.path.isabs(fn):
81        dname = os.path.dirname(parentfn)
82        bbpath = "%s:%s" % (dname, data.getVar("BBPATH"))
83        abs_fn, attempts = bb.utils.which(bbpath, fn, history=True)
84        if abs_fn and bb.parse.check_dependency(data, abs_fn):
85            logger.warning("Duplicate inclusion for %s in %s" % (abs_fn, data.getVar('FILE')))
86        for af in attempts:
87            bb.parse.mark_dependency(data, af)
88        if abs_fn:
89            fn = abs_fn
90    elif bb.parse.check_dependency(data, fn):
91        logger.warning("Duplicate inclusion for %s in %s" % (fn, data.getVar('FILE')))
92
93    try:
94        bb.parse.handle(fn, data, True)
95    except (IOError, OSError) as exc:
96        if exc.errno == errno.ENOENT:
97            if error_out:
98                raise ParseError("Could not %s file %s" % (error_out, fn), parentfn, lineno)
99            logger.debug(2, "CONF file '%s' not found", fn)
100        else:
101            if error_out:
102                raise ParseError("Could not %s file %s: %s" % (error_out, fn, exc.strerror), parentfn, lineno)
103            else:
104                raise ParseError("Error parsing %s: %s" % (fn, exc.strerror), parentfn, lineno)
105
106# We have an issue where a UI might want to enforce particular settings such as
107# an empty DISTRO variable. If configuration files do something like assigning
108# a weak default, it turns out to be very difficult to filter out these changes,
109# particularly when the weak default might appear half way though parsing a chain
110# of configuration files. We therefore let the UIs hook into configuration file
111# parsing. This turns out to be a hard problem to solve any other way.
112confFilters = []
113
114def handle(fn, data, include):
115    init(data)
116
117    if include == 0:
118        oldfile = None
119    else:
120        oldfile = data.getVar('FILE', False)
121
122    abs_fn = resolve_file(fn, data)
123    f = open(abs_fn, 'r')
124
125    statements = ast.StatementGroup()
126    lineno = 0
127    while True:
128        lineno = lineno + 1
129        s = f.readline()
130        if not s:
131            break
132        w = s.strip()
133        # skip empty lines
134        if not w:
135            continue
136        s = s.rstrip()
137        while s[-1] == '\\':
138            s2 = f.readline().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 on line %s of file %s (%s).\nPlease clarify whether this is all a comment or should be parsed." % (lineno, fn, s))
142            s = s[:-1] + s2
143        # skip comments
144        if s[0] == '#':
145            continue
146        feeder(lineno, s, abs_fn, statements)
147
148    # DONE WITH PARSING... time to evaluate
149    data.setVar('FILE', abs_fn)
150    statements.eval(data)
151    if oldfile:
152        data.setVar('FILE', oldfile)
153
154    f.close()
155
156    for f in confFilters:
157        f(fn, data)
158
159    return data
160
161def feeder(lineno, s, fn, statements):
162    m = __config_regexp__.match(s)
163    if m:
164        groupd = m.groupdict()
165        ast.handleData(statements, fn, lineno, groupd)
166        return
167
168    m = __include_regexp__.match(s)
169    if m:
170        ast.handleInclude(statements, fn, lineno, m, False)
171        return
172
173    m = __require_regexp__.match(s)
174    if m:
175        ast.handleInclude(statements, fn, lineno, m, True)
176        return
177
178    m = __export_regexp__.match(s)
179    if m:
180        ast.handleExport(statements, fn, lineno, m)
181        return
182
183    m = __unset_regexp__.match(s)
184    if m:
185        ast.handleUnset(statements, fn, lineno, m)
186        return
187
188    m = __unset_flag_regexp__.match(s)
189    if m:
190        ast.handleUnsetFlag(statements, fn, lineno, m)
191        return
192
193    raise ParseError("unparsed line: '%s'" % s, fn, lineno);
194
195# Add us to the handlers list
196from bb.parse import handlers
197handlers.append({'supports': supports, 'handle': handle, 'init': init})
198del handlers
199