support.py

   1 # Copyright (C) 2006, Thomas Leonard
   2 # See the README file for details, or visit http://0install.net.
   3
   4 import os, sys, tempfile, shutil, traceback
   5 from xml.dom import minidom, XMLNS_NAMESPACE, Node
   6
   7 from zeroinstall.injector.model import Interface, Implementation, Dependency, EnvironmentBinding, escape
   8 from zeroinstall.injector import namespaces, basedir, reader
   9 from zeroinstall.injector.iface_cache import iface_cache
  10 from zeroinstall import SafeException
  11 from zeroinstall.injector import run
  12 from zeroinstall.zerostore import Stores
  13
  14 ENV_FILE = '0compile-env.xml'
  15 XMLNS_0COMPILE = 'http://zero-install.sourceforge.net/2006/namespaces/0compile'
  16
  17 def lookup(id):
  18         if id.startswith('/'):
  19                 if os.path.isdir(id):
  20                         return id
  21                 raise SafeException("Directory '%s' no longer exists. Try '0compile setup'" % id)
  22         return iface_cache.stores.lookup(id)
  23
  24 def get_cached_iface_path(uri):
  25         if uri.startswith('/'):
  26                 if not os.path.isfile(uri):
  27                         raise SafeException("Local source interface '%s' does not exist!" % uri)
  28                 return uri
  29         else:
  30                 path = basedir.load_first_cache(namespaces.config_site, 'interfaces', escape(uri))
  31                 if path and os.path.isfile(path):
  32                         return path
  33                 raise SafeException("Interface '%s' not found in cache. Hint: try '0compile setup'" % uri)
  34
  35 def ensure_dir(d):
  36         if os.path.isdir(d): return
  37         if os.path.exists(d):
  38                 raise SafeException("'%s' exitst, but is not a directory!" % d)
  39         os.mkdir(d)
  40
  41 def find_in_path(prog):
  42         for d in os.environ['PATH'].split(':'):
  43                 path = os.path.join(d, prog)
  44                 if os.path.isfile(path):
  45                         return path
  46         return None
  47
  48 def spawn_and_check(prog, args):
  49         status = os.spawnv(os.P_WAIT, prog, [prog] + args)
  50         if status > 0:
  51                 raise SafeException("Program '%s' failed with exit code %d" % (prog, status))
  52         elif status < 0:
  53                 raise SafeException("Program '%s' failed with signal %d" % (prog, -status))
  54
  55 def wait_for_child(child):
  56         """Wait for child to exit and reap it. Throw an exception if it doesn't return success."""
  57         pid, status = os.waitpid(child, 0)
  58         assert pid == child
  59         if os.WIFEXITED(status):
  60                 exit_code = os.WEXITSTATUS(status)
  61                 if exit_code == 0:
  62                         return
  63                 else:
  64                         raise SafeException('Command failed with exit status %d' % exit_code)
  65         else:
  66                 raise SafeException('Command failed with signal %d' % WTERMSIG(status))
  67
  68 def get_env_doc():
  69         if not os.path.isfile(ENV_FILE):
  70                 raise SafeException("Run 0compile from a directory containing a '%s' file" % ENV_FILE)
  71         return minidom.parse(ENV_FILE)
  72
  73 def children(parent, uri, name):
  74         """Yield all direct children with the given name."""
  75         for x in parent.childNodes:
  76                 if x.nodeType == Node.ELEMENT_NODE and x.namespaceURI == uri and x.localName == name:
  77                         yield x
  78
  79 def spawn_maybe_sandboxed(readable, writable, tmpdir, prog, args):
  80         child = os.fork()
  81         if child == 0:
  82                 try:
  83                         try:
  84                                 exec_maybe_sandboxed(readable, writable, tmpdir, prog, args)
  85                         except:
  86                                 traceback.print_exc()
  87                 finally:
  88                         print >>sys.stderr, "Exec failed"
  89                         os._exit(1)
  90         wait_for_child(child)
  91
  92 def exec_maybe_sandboxed(readable, writable, tmpdir, prog, args):
  93         """execl prog, with (only) the 'writable' directories writable if sandboxing is available.
  94         The readable directories will be readable, as well as various standard locations.
  95         If no sandbox is available, run without a sandbox."""
  96         assert prog.startswith('/')
  97         _pola_run = find_in_path('pola-run')
  98
  99         if _pola_run is None:
 100                 os.execlp(prog, prog, *args)
 101         # We have pola-shell :-)
 102         pola_args = ['--prog', prog, '-B']
 103         for a in args:
 104                 pola_args += ['-a', a]
 105         for r in readable:
 106                 pola_args += ['-f', r]
 107         for w in writable:
 108                 pola_args += ['-fw', w]
 109         pola_args += ['-tw', '/tmp', tmpdir]
 110         os.environ['TMPDIR'] = '/tmp'
 111         os.execl(_pola_run, _pola_run, *pola_args)
 112
 113 class BuildEnv(object):
 114         __slots__ = ['doc', 'interface', 'interfaces', 'root_impl', 'srcdir']
 115
 116         def __init__(self):
 117                 self.doc = get_env_doc()
 118                 root = self.doc.documentElement
 119                 self.interface = root.getAttributeNS(None, 'interface')
 120                 assert self.interface
 121
 122                 self.interfaces = {}
 123                 for child in children(root, XMLNS_0COMPILE, 'interface'):
 124                         iface = self.interface_from_elem(child)
 125                         assert iface.uri not in self.interfaces
 126                         self.interfaces[iface.uri] = iface
 127
 128                 assert self.interface in self.interfaces
 129                 self.root_impl = self.chosen_impl(self.interface)
 130
 131                 if os.path.isdir('src'):
 132                         self.srcdir = os.path.realpath('src')
 133                 else:
 134                         self.srcdir = lookup(self.root_impl.id)
 135
 136         def chosen_impl(self, uri):
 137                 assert uri in self.interfaces
 138                 impls = self.interfaces[uri].implementations.values()
 139                 assert len(impls) == 1
 140                 return impls[0]
 141
 142         def interface_from_elem(self, elem):
 143                 uri = elem.getAttributeNS(None, 'uri')
 144
 145                 iface = Interface(uri)
 146
 147                 impl_elems = list(children(elem, XMLNS_0COMPILE, 'implementation'))
 148                 assert len(impl_elems) == 1
 149                 impl_elem = impl_elems[0]
 150
 151                 impl = iface.get_impl(impl_elem.getAttributeNS(None, 'id'))
 152                 impl.main = impl_elem.getAttributeNS(None, 'main') or None
 153                 impl.version = reader.parse_version(impl_elem.getAttributeNS(None, 'version'))
 154
 155                 for x in impl_elem.attributes.values():
 156                         impl.metadata[x.name] = x.value
 157
 158                 for dep_elem in children(impl_elem, XMLNS_0COMPILE, 'requires'):
 159                         dep_uri = dep_elem.getAttributeNS(None, 'interface')
 160                         dep = Dependency(dep_uri)
 161                         impl.dependencies[dep_uri] = dep
 162
 163                         for e in children(dep_elem, XMLNS_0COMPILE, 'environment'):
 164                                 env = EnvironmentBinding(e.getAttributeNS(None, 'name'),
 165                                                          e.getAttributeNS(None, 'insert'),
 166                                                          e.getAttributeNS(None, 'default') or None)
 167                                 dep.bindings.append(env)
 168
 169                 return iface
 170
 171 def depth(node):
 172         root = node.ownerDocument.documentElement
 173         depth = 0
 174         while node and node is not root:
 175                 node = node.parentNode
 176                 depth += 1
 177         return depth