M7350/oe-core/bitbake/lib/bb/pysh/interp.py
2024-09-09 08:52:07 +00:00

1368 lines
49 KiB
Python

# interp.py - shell interpreter for pysh.
#
# Copyright 2007 Patrick Mezard
#
# This software may be used and distributed according to the terms
# of the GNU General Public License, incorporated herein by reference.
"""Implement the shell interpreter.
Most references are made to "The Open Group Base Specifications Issue 6".
<http://www.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html>
"""
# TODO: document the fact input streams must implement fileno() so Popen will work correctly.
# it requires non-stdin stream to be implemented as files. Still to be tested...
# DOC: pathsep is used in PATH instead of ':'. Clearly, there are path syntax issues here.
# TODO: stop command execution upon error.
# TODO: sort out the filename/io_number mess. It should be possible to use filenames only.
# TODO: review subshell implementation
# TODO: test environment cloning for non-special builtins
# TODO: set -x should not rebuild commands from tokens, assignments/redirections are lost
# TODO: unit test for variable assignment
# TODO: test error management wrt error type/utility type
# TODO: test for binary output everywhere
# BUG: debug-parsing does not pass log file to PLY. Maybe a PLY upgrade is necessary.
import base64
import cPickle as pickle
import errno
import glob
import os
import re
import subprocess
import sys
import tempfile
try:
s = set()
del s
except NameError:
from Set import Set as set
import builtin
from sherrors import *
import pyshlex
import pyshyacc
def mappend(func, *args, **kargs):
"""Like map but assume func returns a list. Returned lists are merged into
a single one.
"""
return reduce(lambda a,b: a+b, map(func, *args, **kargs), [])
class FileWrapper:
"""File object wrapper to ease debugging.
Allow mode checking and implement file duplication through a simple
reference counting scheme. Not sure the latter is really useful since
only real file descriptors can be used.
"""
def __init__(self, mode, file, close=True):
if mode not in ('r', 'w', 'a'):
raise IOError('invalid mode: %s' % mode)
self._mode = mode
self._close = close
if isinstance(file, FileWrapper):
if file._refcount[0] <= 0:
raise IOError(0, 'Error')
self._refcount = file._refcount
self._refcount[0] += 1
self._file = file._file
else:
self._refcount = [1]
self._file = file
def dup(self):
return FileWrapper(self._mode, self, self._close)
def fileno(self):
"""fileno() should be only necessary for input streams."""
return self._file.fileno()
def read(self, size=-1):
if self._mode!='r':
raise IOError(0, 'Error')
return self._file.read(size)
def readlines(self, *args, **kwargs):
return self._file.readlines(*args, **kwargs)
def write(self, s):
if self._mode not in ('w', 'a'):
raise IOError(0, 'Error')
return self._file.write(s)
def flush(self):
self._file.flush()
def close(self):
if not self._refcount:
return
assert self._refcount[0] > 0
self._refcount[0] -= 1
if self._refcount[0] == 0:
self._mode = 'c'
if self._close:
self._file.close()
self._refcount = None
def mode(self):
return self._mode
def __getattr__(self, name):
if name == 'name':
self.name = getattr(self._file, name)
return self.name
else:
raise AttributeError(name)
def __del__(self):
self.close()
def win32_open_devnull(mode):
return open('NUL', mode)
class Redirections:
"""Stores open files and their mapping to pseudo-sh file descriptor.
"""
# BUG: redirections are not handled correctly: 1>&3 2>&3 3>&4 does
# not make 1 to redirect to 4
def __init__(self, stdin=None, stdout=None, stderr=None):
self._descriptors = {}
if stdin is not None:
self._add_descriptor(0, stdin)
if stdout is not None:
self._add_descriptor(1, stdout)
if stderr is not None:
self._add_descriptor(2, stderr)
def add_here_document(self, interp, name, content, io_number=None):
if io_number is None:
io_number = 0
if name==pyshlex.unquote_wordtree(name):
content = interp.expand_here_document(('TOKEN', content))
# Write document content in a temporary file
tmp = tempfile.TemporaryFile()
try:
tmp.write(content)
tmp.flush()
tmp.seek(0)
self._add_descriptor(io_number, FileWrapper('r', tmp))
except:
tmp.close()
raise
def add(self, interp, op, filename, io_number=None):
if op not in ('<', '>', '>|', '>>', '>&'):
# TODO: add descriptor duplication and here_documents
raise RedirectionError('Unsupported redirection operator "%s"' % op)
if io_number is not None:
io_number = int(io_number)
if (op == '>&' and filename.isdigit()) or filename=='-':
# No expansion for file descriptors, quote them if you want a filename
fullname = filename
else:
if filename.startswith('/'):
# TODO: win32 kludge
if filename=='/dev/null':
fullname = 'NUL'
else:
# TODO: handle absolute pathnames, they are unlikely to exist on the
# current platform (win32 for instance).
raise NotImplementedError()
else:
fullname = interp.expand_redirection(('TOKEN', filename))
if not fullname:
raise RedirectionError('%s: ambiguous redirect' % filename)
# Build absolute path based on PWD
fullname = os.path.join(interp.get_env()['PWD'], fullname)
if op=='<':
return self._add_input_redirection(interp, fullname, io_number)
elif op in ('>', '>|'):
clobber = ('>|'==op)
return self._add_output_redirection(interp, fullname, io_number, clobber)
elif op=='>>':
return self._add_output_appending(interp, fullname, io_number)
elif op=='>&':
return self._dup_output_descriptor(fullname, io_number)
def close(self):
if self._descriptors is not None:
for desc in self._descriptors.itervalues():
desc.flush()
desc.close()
self._descriptors = None
def stdin(self):
return self._descriptors[0]
def stdout(self):
return self._descriptors[1]
def stderr(self):
return self._descriptors[2]
def clone(self):
clone = Redirections()
for desc, fileobj in self._descriptors.iteritems():
clone._descriptors[desc] = fileobj.dup()
return clone
def _add_output_redirection(self, interp, filename, io_number, clobber):
if io_number is None:
# io_number default to standard output
io_number = 1
if not clobber and interp.get_env().has_opt('-C') and os.path.isfile(filename):
# File already exist in no-clobber mode, bail out
raise RedirectionError('File "%s" already exists' % filename)
# Open and register
self._add_file_descriptor(io_number, filename, 'w')
def _add_output_appending(self, interp, filename, io_number):
if io_number is None:
io_number = 1
self._add_file_descriptor(io_number, filename, 'a')
def _add_input_redirection(self, interp, filename, io_number):
if io_number is None:
io_number = 0
self._add_file_descriptor(io_number, filename, 'r')
def _add_file_descriptor(self, io_number, filename, mode):
try:
if filename.startswith('/'):
if filename=='/dev/null':
f = win32_open_devnull(mode+'b')
else:
# TODO: handle absolute pathnames, they are unlikely to exist on the
# current platform (win32 for instance).
raise NotImplementedError('cannot open absolute path %s' % repr(filename))
else:
f = file(filename, mode+'b')
except IOError as e:
raise RedirectionError(str(e))
wrapper = None
try:
wrapper = FileWrapper(mode, f)
f = None
self._add_descriptor(io_number, wrapper)
except:
if f: f.close()
if wrapper: wrapper.close()
raise
def _dup_output_descriptor(self, source_fd, dest_fd):
if source_fd is None:
source_fd = 1
self._dup_file_descriptor(source_fd, dest_fd, 'w')
def _dup_file_descriptor(self, source_fd, dest_fd, mode):
source_fd = int(source_fd)
if source_fd not in self._descriptors:
raise RedirectionError('"%s" is not a valid file descriptor' % str(source_fd))
source = self._descriptors[source_fd]
if source.mode()!=mode:
raise RedirectionError('Descriptor %s cannot be duplicated in mode "%s"' % (str(source), mode))
if dest_fd=='-':
# Close the source descriptor
del self._descriptors[source_fd]
source.close()
else:
dest_fd = int(dest_fd)
if dest_fd not in self._descriptors:
raise RedirectionError('Cannot replace file descriptor %s' % str(dest_fd))
dest = self._descriptors[dest_fd]
if dest.mode()!=mode:
raise RedirectionError('Descriptor %s cannot be cannot be redirected in mode "%s"' % (str(dest), mode))
self._descriptors[dest_fd] = source.dup()
dest.close()
def _add_descriptor(self, io_number, file):
io_number = int(io_number)
if io_number in self._descriptors:
# Close the current descriptor
d = self._descriptors[io_number]
del self._descriptors[io_number]
d.close()
self._descriptors[io_number] = file
def __str__(self):
names = [('%d=%r' % (k, getattr(v, 'name', None))) for k,v
in self._descriptors.iteritems()]
names = ','.join(names)
return 'Redirections(%s)' % names
def __del__(self):
self.close()
def cygwin_to_windows_path(path):
"""Turn /cygdrive/c/foo into c:/foo, or return path if it
is not a cygwin path.
"""
if not path.startswith('/cygdrive/'):
return path
path = path[len('/cygdrive/'):]
path = path[:1] + ':' + path[1:]
return path
def win32_to_unix_path(path):
if path is not None:
path = path.replace('\\', '/')
return path
_RE_SHEBANG = re.compile(r'^\#!\s?([^\s]+)(?:\s([^\s]+))?')
_SHEBANG_CMDS = {
'/usr/bin/env': 'env',
'/bin/sh': 'pysh',
'python': 'python',
}
def resolve_shebang(path, ignoreshell=False):
"""Return a list of arguments as shebang interpreter call or an empty list
if path does not refer to an executable script.
See <http://www.opengroup.org/austin/docs/austin_51r2.txt>.
ignoreshell - set to True to ignore sh shebangs. Return an empty list instead.
"""
try:
f = file(path)
try:
# At most 80 characters in the first line
header = f.read(80).splitlines()[0]
finally:
f.close()
m = _RE_SHEBANG.search(header)
if not m:
return []
cmd, arg = m.group(1,2)
if os.path.isfile(cmd):
# Keep this one, the hg script for instance contains a weird windows
# shebang referencing the current python install.
cmdfile = os.path.basename(cmd).lower()
if cmdfile == 'python.exe':
cmd = 'python'
pass
elif cmd not in _SHEBANG_CMDS:
raise CommandNotFound('Unknown interpreter "%s" referenced in '\
'shebang' % header)
cmd = _SHEBANG_CMDS.get(cmd)
if cmd is None or (ignoreshell and cmd == 'pysh'):
return []
if arg is None:
return [cmd, win32_to_unix_path(path)]
return [cmd, arg, win32_to_unix_path(path)]
except IOError as e:
if e.errno!=errno.ENOENT and \
(e.errno!=errno.EPERM and not os.path.isdir(path)): # Opening a directory raises EPERM
raise
return []
def win32_find_in_path(name, path):
if isinstance(path, str):
path = path.split(os.pathsep)
exts = os.environ.get('PATHEXT', '').lower().split(os.pathsep)
for p in path:
p_name = os.path.join(p, name)
prefix = resolve_shebang(p_name)
if prefix:
return prefix
for ext in exts:
p_name_ext = p_name + ext
if os.path.exists(p_name_ext):
return [win32_to_unix_path(p_name_ext)]
return []
class Traps(dict):
def __setitem__(self, key, value):
if key not in ('EXIT',):
raise NotImplementedError()
super(Traps, self).__setitem__(key, value)
# IFS white spaces character class
_IFS_WHITESPACES = (' ', '\t', '\n')
class Environment:
"""Environment holds environment variables, export table, function
definitions and whatever is defined in 2.12 "Shell Execution Environment",
redirection excepted.
"""
def __init__(self, pwd):
self._opt = set() #Shell options
self._functions = {}
self._env = {'?': '0', '#': '0'}
self._exported = set([
'HOME', 'IFS', 'PATH'
])
# Set environment vars with side-effects
self._ifs_ws = None # Set of IFS whitespace characters
self._ifs_re = None # Regular expression used to split between words using IFS classes
self['IFS'] = ''.join(_IFS_WHITESPACES) #Default environment values
self['PWD'] = pwd
self.traps = Traps()
def clone(self, subshell=False):
env = Environment(self['PWD'])
env._opt = set(self._opt)
for k,v in self.get_variables().iteritems():
if k in self._exported:
env.export(k,v)
elif subshell:
env[k] = v
if subshell:
env._functions = dict(self._functions)
return env
def __getitem__(self, key):
if key in ('@', '*', '-', '$'):
raise NotImplementedError('%s is not implemented' % repr(key))
return self._env[key]
def get(self, key, defval=None):
try:
return self[key]
except KeyError:
return defval
def __setitem__(self, key, value):
if key=='IFS':
# Update the whitespace/non-whitespace classes
self._update_ifs(value)
elif key=='PWD':
pwd = os.path.abspath(value)
if not os.path.isdir(pwd):
raise VarAssignmentError('Invalid directory %s' % value)
value = pwd
elif key in ('?', '!'):
value = str(int(value))
self._env[key] = value
def __delitem__(self, key):
if key in ('IFS', 'PWD', '?'):
raise VarAssignmentError('%s cannot be unset' % key)
del self._env[key]
def __contains__(self, item):
return item in self._env
def set_positional_args(self, args):
"""Set the content of 'args' as positional argument from 1 to len(args).
Return previous argument as a list of strings.
"""
# Save and remove previous arguments
prevargs = []
for i in xrange(int(self._env['#'])):
i = str(i+1)
prevargs.append(self._env[i])
del self._env[i]
self._env['#'] = '0'
#Set new ones
for i,arg in enumerate(args):
self._env[str(i+1)] = str(arg)
self._env['#'] = str(len(args))
return prevargs
def get_positional_args(self):
return [self._env[str(i+1)] for i in xrange(int(self._env['#']))]
def get_variables(self):
return dict(self._env)
def export(self, key, value=None):
if value is not None:
self[key] = value
self._exported.add(key)
def get_exported(self):
return [(k,self._env.get(k)) for k in self._exported]
def split_fields(self, word):
if not self._ifs_ws or not word:
return [word]
return re.split(self._ifs_re, word)
def _update_ifs(self, value):
"""Update the split_fields related variables when IFS character set is
changed.
"""
# TODO: handle NULL IFS
# Separate characters in whitespace and non-whitespace
chars = set(value)
ws = [c for c in chars if c in _IFS_WHITESPACES]
nws = [c for c in chars if c not in _IFS_WHITESPACES]
# Keep whitespaces in a string for left and right stripping
self._ifs_ws = ''.join(ws)
# Build a regexp to split fields
trailing = '[' + ''.join([re.escape(c) for c in ws]) + ']'
if nws:
# First, the single non-whitespace occurence.
nws = '[' + ''.join([re.escape(c) for c in nws]) + ']'
nws = '(?:' + trailing + '*' + nws + trailing + '*' + '|' + trailing + '+)'
else:
# Then mix all parts with quantifiers
nws = trailing + '+'
self._ifs_re = re.compile(nws)
def has_opt(self, opt, val=None):
return (opt, val) in self._opt
def set_opt(self, opt, val=None):
self._opt.add((opt, val))
def find_in_path(self, name, pwd=False):
path = self._env.get('PATH', '').split(os.pathsep)
if pwd:
path[:0] = [self['PWD']]
if os.name == 'nt':
return win32_find_in_path(name, self._env.get('PATH', ''))
else:
raise NotImplementedError()
def define_function(self, name, body):
if not is_name(name):
raise ShellSyntaxError('%s is not a valid function name' % repr(name))
self._functions[name] = body
def remove_function(self, name):
del self._functions[name]
def is_function(self, name):
return name in self._functions
def get_function(self, name):
return self._functions.get(name)
name_charset = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_'
name_charset = dict(zip(name_charset,name_charset))
def match_name(s):
"""Return the length in characters of the longest prefix made of name
allowed characters in s.
"""
for i,c in enumerate(s):
if c not in name_charset:
return s[:i]
return s
def is_name(s):
return len([c for c in s if c not in name_charset])<=0
def is_special_param(c):
return len(c)==1 and c in ('@','*','#','?','-','$','!','0')
def utility_not_implemented(name, *args, **kwargs):
raise NotImplementedError('%s utility is not implemented' % name)
class Utility:
"""Define utilities properties:
func -- utility callable. See builtin module for utility samples.
is_special -- see XCU 2.8.
"""
def __init__(self, func, is_special=0):
self.func = func
self.is_special = bool(is_special)
def encodeargs(args):
def encodearg(s):
lines = base64.encodestring(s)
lines = [l.splitlines()[0] for l in lines]
return ''.join(lines)
s = pickle.dumps(args)
return encodearg(s)
def decodeargs(s):
s = base64.decodestring(s)
return pickle.loads(s)
class GlobError(Exception):
pass
class Options:
def __init__(self):
# True if Mercurial operates with binary streams
self.hgbinary = True
class Interpreter:
# Implementation is very basic: the execute() method just makes a DFS on the
# AST and execute nodes one by one. Nodes are tuple (name,obj) where name
# is a string identifier and obj the AST element returned by the parser.
#
# Handler are named after the node identifiers.
# TODO: check node names and remove the switch in execute with some
# dynamic getattr() call to find node handlers.
"""Shell interpreter.
The following debugging flags can be passed:
debug-parsing - enable PLY debugging.
debug-tree - print the generated AST.
debug-cmd - trace command execution before word expansion, plus exit status.
debug-utility - trace utility execution.
"""
# List supported commands.
COMMANDS = {
'cat': Utility(builtin.utility_cat,),
'cd': Utility(builtin.utility_cd,),
':': Utility(builtin.utility_colon,),
'echo': Utility(builtin.utility_echo),
'env': Utility(builtin.utility_env),
'exit': Utility(builtin.utility_exit),
'export': Utility(builtin.builtin_export, is_special=1),
'egrep': Utility(builtin.utility_egrep),
'fgrep': Utility(builtin.utility_fgrep),
'gunzip': Utility(builtin.utility_gunzip),
'kill': Utility(builtin.utility_kill),
'mkdir': Utility(builtin.utility_mkdir),
'netstat': Utility(builtin.utility_netstat),
'printf': Utility(builtin.utility_printf),
'pwd': Utility(builtin.utility_pwd),
'return': Utility(builtin.builtin_return, is_special=1),
'sed': Utility(builtin.utility_sed,),
'set': Utility(builtin.builtin_set,),
'shift': Utility(builtin.builtin_shift,),
'sleep': Utility(builtin.utility_sleep,),
'sort': Utility(builtin.utility_sort,),
'trap': Utility(builtin.builtin_trap, is_special=1),
'true': Utility(builtin.utility_true),
'unset': Utility(builtin.builtin_unset, is_special=1),
'wait': Utility(builtin.builtin_wait, is_special=1),
}
def __init__(self, pwd, debugflags = [], env=None, redirs=None, stdin=None,
stdout=None, stderr=None, opts=Options()):
self._env = env
if self._env is None:
self._env = Environment(pwd)
self._children = {}
self._redirs = redirs
self._close_redirs = False
if self._redirs is None:
if stdin is None:
stdin = sys.stdin
if stdout is None:
stdout = sys.stdout
if stderr is None:
stderr = sys.stderr
stdin = FileWrapper('r', stdin, False)
stdout = FileWrapper('w', stdout, False)
stderr = FileWrapper('w', stderr, False)
self._redirs = Redirections(stdin, stdout, stderr)
self._close_redirs = True
self._debugflags = list(debugflags)
self._logfile = sys.stderr
self._options = opts
def close(self):
"""Must be called when the interpreter is no longer used."""
script = self._env.traps.get('EXIT')
if script:
try:
self.execute_script(script=script)
except:
pass
if self._redirs is not None and self._close_redirs:
self._redirs.close()
self._redirs = None
def log(self, s):
self._logfile.write(s)
self._logfile.flush()
def __getitem__(self, key):
return self._env[key]
def __setitem__(self, key, value):
self._env[key] = value
def options(self):
return self._options
def redirect(self, redirs, ios):
def add_redir(io):
if isinstance(io, pyshyacc.IORedirect):
redirs.add(self, io.op, io.filename, io.io_number)
else:
redirs.add_here_document(self, io.name, io.content, io.io_number)
map(add_redir, ios)
return redirs
def execute_script(self, script=None, ast=None, sourced=False,
scriptpath=None):
"""If script is not None, parse the input. Otherwise takes the supplied
AST. Then execute the AST.
Return the script exit status.
"""
try:
if scriptpath is not None:
self._env['0'] = os.path.abspath(scriptpath)
if script is not None:
debug_parsing = ('debug-parsing' in self._debugflags)
cmds, script = pyshyacc.parse(script, True, debug_parsing)
if 'debug-tree' in self._debugflags:
pyshyacc.print_commands(cmds, self._logfile)
self._logfile.flush()
else:
cmds, script = ast, ''
status = 0
for cmd in cmds:
try:
status = self.execute(cmd)
except ExitSignal as e:
if sourced:
raise
status = int(e.args[0])
return status
except ShellError:
self._env['?'] = 1
raise
if 'debug-utility' in self._debugflags or 'debug-cmd' in self._debugflags:
self.log('returncode ' + str(status)+ '\n')
return status
except CommandNotFound as e:
print >>self._redirs.stderr, str(e)
self._redirs.stderr.flush()
# Command not found by non-interactive shell
# return 127
raise
except RedirectionError as e:
# TODO: should be handled depending on the utility status
print >>self._redirs.stderr, str(e)
self._redirs.stderr.flush()
# Command not found by non-interactive shell
# return 127
raise
def dotcommand(self, env, args):
if len(args) < 1:
raise ShellError('. expects at least one argument')
path = args[0]
if '/' not in path:
found = env.find_in_path(args[0], True)
if found:
path = found[0]
script = file(path).read()
return self.execute_script(script=script, sourced=True)
def execute(self, token, redirs=None):
"""Execute and AST subtree with supplied redirections overriding default
interpreter ones.
Return the exit status.
"""
if not token:
return 0
if redirs is None:
redirs = self._redirs
if isinstance(token, list):
# Commands sequence
res = 0
for t in token:
res = self.execute(t, redirs)
return res
type, value = token
status = 0
if type=='simple_command':
redirs_copy = redirs.clone()
try:
# TODO: define and handle command return values
# TODO: implement set -e
status = self._execute_simple_command(value, redirs_copy)
finally:
redirs_copy.close()
elif type=='pipeline':
status = self._execute_pipeline(value, redirs)
elif type=='and_or':
status = self._execute_and_or(value, redirs)
elif type=='for_clause':
status = self._execute_for_clause(value, redirs)
elif type=='while_clause':
status = self._execute_while_clause(value, redirs)
elif type=='function_definition':
status = self._execute_function_definition(value, redirs)
elif type=='brace_group':
status = self._execute_brace_group(value, redirs)
elif type=='if_clause':
status = self._execute_if_clause(value, redirs)
elif type=='subshell':
status = self.subshell(ast=value.cmds, redirs=redirs)
elif type=='async':
status = self._asynclist(value)
elif type=='redirect_list':
redirs_copy = self.redirect(redirs.clone(), value.redirs)
try:
status = self.execute(value.cmd, redirs_copy)
finally:
redirs_copy.close()
else:
raise NotImplementedError('Unsupported token type ' + type)
if status < 0:
status = 255
return status
def _execute_if_clause(self, if_clause, redirs):
cond_status = self.execute(if_clause.cond, redirs)
if cond_status==0:
return self.execute(if_clause.if_cmds, redirs)
else:
return self.execute(if_clause.else_cmds, redirs)
def _execute_brace_group(self, group, redirs):
status = 0
for cmd in group.cmds:
status = self.execute(cmd, redirs)
return status
def _execute_function_definition(self, fundef, redirs):
self._env.define_function(fundef.name, fundef.body)
return 0
def _execute_while_clause(self, while_clause, redirs):
status = 0
while 1:
cond_status = 0
for cond in while_clause.condition:
cond_status = self.execute(cond, redirs)
if cond_status:
break
for cmd in while_clause.cmds:
status = self.execute(cmd, redirs)
return status
def _execute_for_clause(self, for_clause, redirs):
if not is_name(for_clause.name):
raise ShellSyntaxError('%s is not a valid name' % repr(for_clause.name))
items = mappend(self.expand_token, for_clause.items)
status = 0
for item in items:
self._env[for_clause.name] = item
for cmd in for_clause.cmds:
status = self.execute(cmd, redirs)
return status
def _execute_and_or(self, or_and, redirs):
res = self.execute(or_and.left, redirs)
if (or_and.op=='&&' and res==0) or (or_and.op!='&&' and res!=0):
res = self.execute(or_and.right, redirs)
return res
def _execute_pipeline(self, pipeline, redirs):
if len(pipeline.commands)==1:
status = self.execute(pipeline.commands[0], redirs)
else:
# Execute all commands one after the other
status = 0
inpath, outpath = None, None
try:
# Commands inputs and outputs cannot really be plugged as done
# by a real shell. Run commands sequentially and chain their
# input/output throught temporary files.
tmpfd, inpath = tempfile.mkstemp()
os.close(tmpfd)
tmpfd, outpath = tempfile.mkstemp()
os.close(tmpfd)
inpath = win32_to_unix_path(inpath)
outpath = win32_to_unix_path(outpath)
for i, cmd in enumerate(pipeline.commands):
call_redirs = redirs.clone()
try:
if i!=0:
call_redirs.add(self, '<', inpath)
if i!=len(pipeline.commands)-1:
call_redirs.add(self, '>', outpath)
status = self.execute(cmd, call_redirs)
# Chain inputs/outputs
inpath, outpath = outpath, inpath
finally:
call_redirs.close()
finally:
if inpath: os.remove(inpath)
if outpath: os.remove(outpath)
if pipeline.reverse_status:
status = int(not status)
self._env['?'] = status
return status
def _execute_function(self, name, args, interp, env, stdin, stdout, stderr, *others):
assert interp is self
func = env.get_function(name)
#Set positional parameters
prevargs = None
try:
prevargs = env.set_positional_args(args)
try:
redirs = Redirections(stdin.dup(), stdout.dup(), stderr.dup())
try:
status = self.execute(func, redirs)
finally:
redirs.close()
except ReturnSignal as e:
status = int(e.args[0])
env['?'] = status
return status
finally:
#Reset positional parameters
if prevargs is not None:
env.set_positional_args(prevargs)
def _execute_simple_command(self, token, redirs):
"""Can raise ReturnSignal when return builtin is called, ExitSignal when
exit is called, and other shell exceptions upon builtin failures.
"""
debug_command = 'debug-cmd' in self._debugflags
if debug_command:
self.log('word' + repr(token.words) + '\n')
self.log('assigns' + repr(token.assigns) + '\n')
self.log('redirs' + repr(token.redirs) + '\n')
is_special = None
env = self._env
try:
# Word expansion
args = []
for word in token.words:
args += self.expand_token(word)
if is_special is None and args:
is_special = env.is_function(args[0]) or \
(args[0] in self.COMMANDS and self.COMMANDS[args[0]].is_special)
if debug_command:
self.log('_execute_simple_command' + str(args) + '\n')
if not args:
# Redirections happen is a subshell
redirs = redirs.clone()
elif not is_special:
env = self._env.clone()
# Redirections
self.redirect(redirs, token.redirs)
# Variables assignments
res = 0
for type,(k,v) in token.assigns:
status, expanded = self.expand_variable((k,v))
if status is not None:
res = status
if args:
env.export(k, expanded)
else:
env[k] = expanded
if args and args[0] in ('.', 'source'):
res = self.dotcommand(env, args[1:])
elif args:
if args[0] in self.COMMANDS:
command = self.COMMANDS[args[0]]
elif env.is_function(args[0]):
command = Utility(self._execute_function, is_special=True)
else:
if not '/' in args[0].replace('\\', '/'):
cmd = env.find_in_path(args[0])
if not cmd:
# TODO: test error code on unknown command => 127
raise CommandNotFound('Unknown command: "%s"' % args[0])
else:
# Handle commands like '/cygdrive/c/foo.bat'
cmd = cygwin_to_windows_path(args[0])
if not os.path.exists(cmd):
raise CommandNotFound('%s: No such file or directory' % args[0])
shebang = resolve_shebang(cmd)
if shebang:
cmd = shebang
else:
cmd = [cmd]
args[0:1] = cmd
command = Utility(builtin.run_command)
# Command execution
if 'debug-cmd' in self._debugflags:
self.log('redirections ' + str(redirs) + '\n')
res = command.func(args[0], args[1:], self, env,
redirs.stdin(), redirs.stdout(),
redirs.stderr(), self._debugflags)
if self._env.has_opt('-x'):
# Trace command execution in shell environment
# BUG: would be hard to reproduce a real shell behaviour since
# the AST is not annotated with source lines/tokens.
self._redirs.stdout().write(' '.join(args))
except ReturnSignal:
raise
except ShellError as e:
if is_special or isinstance(e, (ExitSignal,
ShellSyntaxError, ExpansionError)):
raise e
self._redirs.stderr().write(str(e)+'\n')
return 1
return res
def expand_token(self, word):
"""Expand a word as specified in [2.6 Word Expansions]. Return the list
of expanded words.
"""
status, wtrees = self._expand_word(word)
return map(pyshlex.wordtree_as_string, wtrees)
def expand_variable(self, word):
"""Return a status code (or None if no command expansion occurred)
and a single word.
"""
status, wtrees = self._expand_word(word, pathname=False, split=False)
words = map(pyshlex.wordtree_as_string, wtrees)
assert len(words)==1
return status, words[0]
def expand_here_document(self, word):
"""Return the expanded document as a single word. The here document is
assumed to be unquoted.
"""
status, wtrees = self._expand_word(word, pathname=False,
split=False, here_document=True)
words = map(pyshlex.wordtree_as_string, wtrees)
assert len(words)==1
return words[0]
def expand_redirection(self, word):
"""Return a single word."""
return self.expand_variable(word)[1]
def get_env(self):
return self._env
def _expand_word(self, token, pathname=True, split=True, here_document=False):
wtree = pyshlex.make_wordtree(token[1], here_document=here_document)
# TODO: implement tilde expansion
def expand(wtree):
"""Return a pseudo wordtree: the tree or its subelements can be empty
lists when no value result from the expansion.
"""
status = None
for part in wtree:
if not isinstance(part, list):
continue
if part[0]in ("'", '\\'):
continue
elif part[0] in ('`', '$('):
status, result = self._expand_command(part)
part[:] = result
elif part[0] in ('$', '${'):
part[:] = self._expand_parameter(part, wtree[0]=='"', split)
elif part[0] in ('', '"'):
status, result = expand(part)
part[:] = result
else:
raise NotImplementedError('%s expansion is not implemented'
% part[0])
# [] is returned when an expansion result in no-field,
# like an empty $@
wtree = [p for p in wtree if p != []]
if len(wtree) < 3:
return status, []
return status, wtree
status, wtree = expand(wtree)
if len(wtree) == 0:
return status, wtree
wtree = pyshlex.normalize_wordtree(wtree)
if split:
wtrees = self._split_fields(wtree)
else:
wtrees = [wtree]
if pathname:
wtrees = mappend(self._expand_pathname, wtrees)
wtrees = map(self._remove_quotes, wtrees)
return status, wtrees
def _expand_command(self, wtree):
# BUG: there is something to do with backslashes and quoted
# characters here
command = pyshlex.wordtree_as_string(wtree[1:-1])
status, output = self.subshell_output(command)
return status, ['', output, '']
def _expand_parameter(self, wtree, quoted=False, split=False):
"""Return a valid wtree or an empty list when no parameter results."""
# Get the parameter name
# TODO: implement weird expansion rules with ':'
name = pyshlex.wordtree_as_string(wtree[1:-1])
if not is_name(name) and not is_special_param(name):
raise ExpansionError('Bad substitution "%s"' % name)
# TODO: implement special parameters
if name in ('@', '*'):
args = self._env.get_positional_args()
if len(args) == 0:
return []
if len(args)<2:
return ['', ''.join(args), '']
sep = self._env.get('IFS', '')[:1]
if split and quoted and name=='@':
# Introduce a new token to tell the caller that these parameters
# cause a split as specified in 2.5.2
return ['@'] + args + ['']
else:
return ['', sep.join(args), '']
return ['', self._env.get(name, ''), '']
def _split_fields(self, wtree):
def is_empty(split):
return split==['', '', '']
def split_positional(quoted):
# Return a list of wtree split according positional parameters rules.
# All remaining '@' groups are removed.
assert quoted[0]=='"'
splits = [[]]
for part in quoted:
if not isinstance(part, list) or part[0]!='@':
splits[-1].append(part)
else:
# Empty or single argument list were dealt with already
assert len(part)>3
# First argument must join with the beginning part of the original word
splits[-1].append(part[1])
# Create double-quotes expressions for every argument after the first
for arg in part[2:-1]:
splits[-1].append('"')
splits.append(['"', arg])
return splits
# At this point, all expansions but pathnames have occured. Only quoted
# and positional sequences remain. Thus, all candidates for field splitting
# are in the tree root, or are positional splits ('@') and lie in root
# children.
if not wtree or wtree[0] not in ('', '"'):
# The whole token is quoted or empty, nothing to split
return [wtree]
if wtree[0]=='"':
wtree = ['', wtree, '']
result = [['', '']]
for part in wtree[1:-1]:
if isinstance(part, list):
if part[0]=='"':
splits = split_positional(part)
if len(splits)<=1:
result[-1] += [part, '']
else:
# Terminate the current split
result[-1] += [splits[0], '']
result += splits[1:-1]
# Create a new split
result += [['', splits[-1], '']]
else:
result[-1] += [part, '']
else:
splits = self._env.split_fields(part)
if len(splits)<=1:
# No split
result[-1][-1] += part
else:
# Terminate the current resulting part and create a new one
result[-1][-1] += splits[0]
result[-1].append('')
result += [['', r, ''] for r in splits[1:-1]]
result += [['', splits[-1]]]
result[-1].append('')
# Leading and trailing empty groups come from leading/trailing blanks
if result and is_empty(result[-1]):
result[-1:] = []
if result and is_empty(result[0]):
result[:1] = []
return result
def _expand_pathname(self, wtree):
"""See [2.6.6 Pathname Expansion]."""
if self._env.has_opt('-f'):
return [wtree]
# All expansions have been performed, only quoted sequences should remain
# in the tree. Generate the pattern by folding the tree, escaping special
# characters when appear quoted
special_chars = '*?[]'
def make_pattern(wtree):
subpattern = []
for part in wtree[1:-1]:
if isinstance(part, list):
part = make_pattern(part)
elif wtree[0]!='':
for c in part:
# Meta-characters cannot be quoted
if c in special_chars:
raise GlobError()
subpattern.append(part)
return ''.join(subpattern)
def pwd_glob(pattern):
cwd = os.getcwd()
os.chdir(self._env['PWD'])
try:
return glob.glob(pattern)
finally:
os.chdir(cwd)
#TODO: check working directory issues here wrt relative patterns
try:
pattern = make_pattern(wtree)
paths = pwd_glob(pattern)
except GlobError:
# BUG: Meta-characters were found in quoted sequences. The should
# have been used literally but this is unsupported in current glob module.
# Instead we consider the whole tree must be used literally and
# therefore there is no point in globbing. This is wrong when meta
# characters are mixed with quoted meta in the same pattern like:
# < foo*"py*" >
paths = []
if not paths:
return [wtree]
return [['', path, ''] for path in paths]
def _remove_quotes(self, wtree):
"""See [2.6.7 Quote Removal]."""
def unquote(wtree):
unquoted = []
for part in wtree[1:-1]:
if isinstance(part, list):
part = unquote(part)
unquoted.append(part)
return ''.join(unquoted)
return ['', unquote(wtree), '']
def subshell(self, script=None, ast=None, redirs=None):
"""Execute the script or AST in a subshell, with inherited redirections
if redirs is not None.
"""
if redirs:
sub_redirs = redirs
else:
sub_redirs = redirs.clone()
subshell = None
try:
subshell = Interpreter(None, self._debugflags, self._env.clone(True),
sub_redirs, opts=self._options)
return subshell.execute_script(script, ast)
finally:
if not redirs: sub_redirs.close()
if subshell: subshell.close()
def subshell_output(self, script):
"""Execute the script in a subshell and return the captured output."""
# Create temporary file to capture subshell output
tmpfd, tmppath = tempfile.mkstemp()
try:
tmpfile = os.fdopen(tmpfd, 'wb')
stdout = FileWrapper('w', tmpfile)
redirs = Redirections(self._redirs.stdin().dup(),
stdout,
self._redirs.stderr().dup())
try:
status = self.subshell(script=script, redirs=redirs)
finally:
redirs.close()
redirs = None
# Extract subshell standard output
tmpfile = open(tmppath, 'rb')
try:
output = tmpfile.read()
return status, output.rstrip('\n')
finally:
tmpfile.close()
finally:
os.remove(tmppath)
def _asynclist(self, cmd):
args = (self._env.get_variables(), cmd)
arg = encodeargs(args)
assert len(args) < 30*1024
cmd = ['pysh.bat', '--ast', '-c', arg]
p = subprocess.Popen(cmd, cwd=self._env['PWD'])
self._children[p.pid] = p
self._env['!'] = p.pid
return 0
def wait(self, pids=None):
if not pids:
pids = self._children.keys()
status = 127
for pid in pids:
if pid not in self._children:
continue
p = self._children.pop(pid)
status = p.wait()
return status