Namespace sanitizing, step 2

Rename portage.exec to portage.process to avoid syntax errors


svn path=/main/trunk/; revision=5780

1 files changed, 336 insertions, 0 deletions

diff --git a/pym/portage/process.py b/pym/portage/process.py
new file mode 100644
index 000000000..20b1d705c
--- /dev/null
+++ b/pym/portage/process.py
@@ -0,0 +1,336 @@
+# portage.py -- core Portage functionality
+# Copyright 1998-2004 Gentoo Foundation
+# Distributed under the terms of the GNU General Public License v2
+# $Id$
+
+
+import os, atexit, signal, sys
+import portage.data
+
+from portage.util import dump_traceback
+from portage.const import BASH_BINARY, SANDBOX_BINARY
+
+
+try:
+	import resource
+	max_fd_limit = resource.getrlimit(resource.RLIMIT_NOFILE)[0]
+except ImportError:
+	max_fd_limit = 256
+
+if os.path.isdir("/proc/%i/fd" % os.getpid()):
+	def get_open_fds():
+		return map(int, [fd for fd in os.listdir("/proc/%i/fd" % os.getpid()) if fd.isdigit()])
+else:
+	def get_open_fds():
+		return xrange(max_fd_limit)
+
+sandbox_capable = (os.path.isfile(SANDBOX_BINARY) and
+                   os.access(SANDBOX_BINARY, os.X_OK))
+
+def spawn_bash(mycommand, debug=False, opt_name=None, **keywords):
+	"""
+	Spawns a bash shell running a specific commands
+	
+	@param mycommand: The command for bash to run
+	@type mycommand: String
+	@param debug: Turn bash debugging on (set -x)
+	@type debug: Boolean
+	@param opt_name: Name of the spawned process (detaults to binary name)
+	@type opt_name: String
+	@param keywords: Extra Dictionary arguments to pass to spawn
+	@type keywords: Dictionary
+	"""
+
+	args = [BASH_BINARY]
+	if not opt_name:
+		opt_name = os.path.basename(mycommand.split()[0])
+	if debug:
+		# Print commands and their arguments as they are executed.
+		args.append("-x")
+	args.append("-c")
+	args.append(mycommand)
+	return spawn(args, opt_name=opt_name, **keywords)
+
+def spawn_sandbox(mycommand, opt_name=None, **keywords):
+	if not sandbox_capable:
+		return spawn_bash(mycommand, opt_name=opt_name, **keywords)
+	args=[SANDBOX_BINARY]
+	if not opt_name:
+		opt_name = os.path.basename(mycommand.split()[0])
+	args.append(mycommand)
+	return spawn(args, opt_name=opt_name, **keywords)
+
+_exithandlers = []
+def atexit_register(func, *args, **kargs):
+	"""Wrapper around atexit.register that is needed in order to track
+	what is registered.  For example, when portage restarts itself via
+	os.execv, the atexit module does not work so we have to do it
+	manually by calling the run_exitfuncs() function in this module."""
+	_exithandlers.append((func, args, kargs))
+
+def run_exitfuncs():
+	"""This should behave identically to the routine performed by
+	the atexit module at exit time.  It's only necessary to call this
+	function when atexit will not work (because of os.execv, for
+	example)."""
+
+	# This function is a copy of the private atexit._run_exitfuncs()
+	# from the python 2.4.2 sources.  The only difference from the
+	# original function is in the output to stderr.
+	exc_info = None
+	while _exithandlers:
+		func, targs, kargs = _exithandlers.pop()
+		try:
+			func(*targs, **kargs)
+		except SystemExit:
+			exc_info = sys.exc_info()
+		except: # No idea what they called, so we need this broad except here.
+			dump_traceback("Error in portage.process.run_exitfuncs", noiselevel=0)
+			exc_info = sys.exc_info()
+
+	if exc_info is not None:
+		raise exc_info[0], exc_info[1], exc_info[2]
+
+atexit.register(run_exitfuncs)
+
+# We need to make sure that any processes spawned are killed off when
+# we exit. spawn() takes care of adding and removing pids to this list
+# as it creates and cleans up processes.
+spawned_pids = []
+def cleanup():
+	while spawned_pids:
+		pid = spawned_pids.pop()
+		try:
+			if os.waitpid(pid, os.WNOHANG) == (0, 0):
+				os.kill(pid, signal.SIGTERM)
+				os.waitpid(pid, 0)
+		except OSError:
+			# This pid has been cleaned up outside
+			# of spawn().
+			pass
+
+atexit_register(cleanup)
+
+def spawn(mycommand, env={}, opt_name=None, fd_pipes=None, returnpid=False,
+          uid=None, gid=None, groups=None, umask=None, logfile=None,
+          path_lookup=True):
+	"""
+	Spawns a given command.
+	
+	@param mycommand: the command to execute
+	@type mycommand: String or List (Popen style list)
+	@param env: A dict of Key=Value pairs for env variables
+	@type env: Dictionary
+	@param opt_name: an optional name for the spawn'd process (defaults to the binary name)
+	@type opt_name: String
+	@param fd_pipes: A dict of mapping for pipes, { '0': stdin, '1': stdout } for example
+	@type fd_pipes: Dictionary
+	@param returnpid: Return the Process IDs for a successful spawn.
+	NOTE: This requires the caller clean up all the PIDs, otherwise spawn will clean them.
+	@type returnpid: Boolean
+	@param uid: User ID to spawn as; useful for dropping privilages
+	@type uid: Integer
+	@param gid: Group ID to spawn as; useful for dropping privilages
+	@type gid: Integer
+	@param groups: Group ID's to spawn in: useful for having the process run in multiple group contexts.
+	@type groups: List
+	@param umask: An integer representing the umask for the process (see man chmod for umask details)
+	@type umask: Integer
+	@param logfile: name of a file to use for logging purposes
+	@type logfile: String
+	@param path_lookup: If the binary is not fully specified then look for it in PATH
+	@type path_lookup: Boolean
+	
+	logfile requires stdout and stderr to be assigned to this process (ie not pointed
+	   somewhere else.)
+	
+	"""
+
+	# mycommand is either a str or a list
+	if isinstance(mycommand, str):
+		mycommand = mycommand.split()
+
+	# If an absolute path to an executable file isn't given
+	# search for it unless we've been told not to.
+	binary = mycommand[0]
+	if (not os.path.isabs(binary) or not os.path.isfile(binary)
+	    or not os.access(binary, os.X_OK)):
+		binary = path_lookup and find_binary(binary) or None
+		if not binary:
+			return -1
+
+	# If we haven't been told what file descriptors to use
+	# default to propogating our stdin, stdout and stderr.
+	if fd_pipes is None:
+		fd_pipes = {0:0, 1:1, 2:2}
+
+	# mypids will hold the pids of all processes created.
+	mypids = []
+
+	if logfile:
+		# Using a log file requires that stdout and stderr
+		# are assigned to the process we're running.
+		if 1 not in fd_pipes or 2 not in fd_pipes:
+			raise ValueError(fd_pipes)
+
+		# Create a pipe
+		(pr, pw) = os.pipe()
+
+		# Create a tee process, giving it our stdout and stderr
+		# as well as the read end of the pipe.
+		mypids.extend(spawn(('tee', '-i', '-a', logfile),
+		              returnpid=True, fd_pipes={0:pr,
+		              1:fd_pipes[1], 2:fd_pipes[2]}))
+
+		# We don't need the read end of the pipe, so close it.
+		os.close(pr)
+
+		# Assign the write end of the pipe to our stdout and stderr.
+		fd_pipes[1] = pw
+		fd_pipes[2] = pw
+
+	pid = os.fork()
+
+	if not pid:
+		try:
+			_exec(binary, mycommand, opt_name, fd_pipes,
+			      env, gid, groups, uid, umask)
+		except Exception, e:
+			# We need to catch _any_ exception so that it doesn't
+			# propogate out of this function and cause exiting
+			# with anything other than os._exit()
+			sys.stderr.write("%s:\n   %s\n" % (e, " ".join(mycommand)))
+			sys.stderr.flush()
+			os._exit(1)
+
+	# Add the pid to our local and the global pid lists.
+	mypids.append(pid)
+	spawned_pids.append(pid)
+
+	# If we started a tee process the write side of the pipe is no
+	# longer needed, so close it.
+	if logfile:
+		os.close(pw)
+
+	# If the caller wants to handle cleaning up the processes, we tell
+	# it about all processes that were created.
+	if returnpid:
+		return mypids
+
+	# Otherwise we clean them up.
+	while mypids:
+
+		# Pull the last reader in the pipe chain. If all processes
+		# in the pipe are well behaved, it will die when the process
+		# it is reading from dies.
+		pid = mypids.pop(0)
+
+		# and wait for it.
+		retval = os.waitpid(pid, 0)[1]
+
+		# When it's done, we can remove it from the
+		# global pid list as well.
+		spawned_pids.remove(pid)
+
+		if retval:
+			# If it failed, kill off anything else that
+			# isn't dead yet.
+			for pid in mypids:
+				if os.waitpid(pid, os.WNOHANG) == (0,0):
+					os.kill(pid, signal.SIGTERM)
+					os.waitpid(pid, 0)
+				spawned_pids.remove(pid)
+
+			# If it got a signal, return the signal that was sent.
+			if (retval & 0xff):
+				return ((retval & 0xff) << 8)
+
+			# Otherwise, return its exit code.
+			return (retval >> 8)
+
+	# Everything succeeded
+	return 0
+
+def _exec(binary, mycommand, opt_name, fd_pipes, env, gid, groups, uid, umask):
+
+	"""
+	Execute a given binary with options
+	
+	@param binary: Name of program to execute
+	@type binary: String
+	@param mycommand: Options for program
+	@type mycommand: String
+	@param opt_name: Name of process (defaults to binary)
+	@type opt_name: String
+	@param fd_pipes: Mapping pipes to destination; { 0:0, 1:1, 2:2 }
+	@type fd_pipes: Dictionary
+	@param env: Key,Value mapping for Environmental Variables
+	@type env: Dictionary
+	@param gid: Group ID to run the process under
+	@type gid: Integer
+	@param groups: Groups the Process should be in.
+	@type groups: Integer
+	@param uid: User ID to run the process under
+	@type uid: Integer
+	@param umask: an int representing a unix umask (see man chmod for umask details)
+	@type umask: Integer
+	@rtype: None
+	@returns: Never returns (calls os.execve)
+	"""
+	
+	# If the process we're creating hasn't been given a name
+	# assign it the name of the executable.
+	if not opt_name:
+		opt_name = os.path.basename(binary)
+
+	# Set up the command's argument list.
+	myargs = [opt_name]
+	myargs.extend(mycommand[1:])
+
+	# Set up the command's pipes.
+	my_fds = {}
+	# To protect from cases where direct assignment could
+	# clobber needed fds ({1:2, 2:1}) we first dupe the fds
+	# into unused fds.
+	for fd in fd_pipes:
+		my_fds[fd] = os.dup(fd_pipes[fd])
+	# Then assign them to what they should be.
+	for fd in my_fds:
+		os.dup2(my_fds[fd], fd)
+	# Then close _all_ fds that haven't been explictly
+	# requested to be kept open.
+	for fd in get_open_fds():
+		if fd not in my_fds:
+			try:
+				os.close(fd)
+			except OSError:
+				pass
+
+	# Set requested process permissions.
+	if gid:
+		os.setgid(gid)
+	if groups:
+		os.setgroups(groups)
+	if uid:
+		os.setuid(uid)
+	if umask:
+		os.umask(umask)
+
+	# And switch to the new process.
+	os.execve(binary, myargs, env)
+
+def find_binary(binary):
+	"""
+	Given a binary name, find the binary in PATH
+	
+	@param binary: Name of the binary to find
+	@type string
+	@rtype: None or string
+	@returns: full path to binary or None if the binary could not be located.
+	"""
+	
+	for path in os.getenv("PATH", "").split(":"):
+		filename = "%s/%s" % (path, binary)
+		if os.access(filename, os.X_OK) and os.path.isfile(filename):
+			return filename
+	return None