zeroinstall/injector/run.py

   1 """
   2 Executes a set of implementations as a program.
   3 """
   4
   5 # Copyright (C) 2009, Thomas Leonard
   6 # See the README file for details, or visit http://0install.net.
   7
   8 from zeroinstall import _
   9 import os, sys
  10 from logging import info
  11 from string import Template
  12
  13 from zeroinstall.injector.model import SafeException, EnvironmentBinding, ExecutableBinding, Command, Dependency
  14 from zeroinstall.injector import namespaces, qdom
  15 from zeroinstall.support import basedir
  16
  17 def do_env_binding(binding, path):
  18         """Update this process's environment by applying the binding.
  19         @param binding: the binding to apply
  20         @type binding: L{model.EnvironmentBinding}
  21         @param path: the selected implementation
  22         @type path: str"""
  23         os.environ[binding.name] = binding.get_value(path,
  24                                         os.environ.get(binding.name, None))
  25         info("%s=%s", binding.name, os.environ[binding.name])
  26
  27 def execute(policy, prog_args, dry_run = False, main = None, wrapper = None):
  28         """Execute program. On success, doesn't return. On failure, raises an Exception.
  29         Returns normally only for a successful dry run.
  30         @param policy: a policy with the selected versions
  31         @type policy: L{policy.Policy}
  32         @param prog_args: arguments to pass to the program
  33         @type prog_args: [str]
  34         @param dry_run: if True, just print a message about what would have happened
  35         @type dry_run: bool
  36         @param main: the name of the binary to run, or None to use the default
  37         @type main: str
  38         @param wrapper: a command to use to actually run the binary, or None to run the binary directly
  39         @type wrapper: str
  40         @precondition: C{policy.ready and policy.get_uncached_implementations() == []}
  41         """
  42         execute_selections(policy.solver.selections, prog_args, dry_run, main, wrapper)
  43
  44 def test_selections(selections, prog_args, dry_run, main, wrapper = None):
  45         """Run the program in a child process, collecting stdout and stderr.
  46         @return: the output produced by the process
  47         @since: 0.27
  48         """
  49         import tempfile
  50         output = tempfile.TemporaryFile(prefix = '0launch-test')
  51         try:
  52                 child = os.fork()
  53                 if child == 0:
  54                         # We are the child
  55                         try:
  56                                 try:
  57                                         os.dup2(output.fileno(), 1)
  58                                         os.dup2(output.fileno(), 2)
  59                                         execute_selections(selections, prog_args, dry_run, main)
  60                                 except:
  61                                         import traceback
  62                                         traceback.print_exc()
  63                         finally:
  64                                 sys.stdout.flush()
  65                                 sys.stderr.flush()
  66                                 os._exit(1)
  67
  68                 info(_("Waiting for test process to finish..."))
  69
  70                 pid, status = os.waitpid(child, 0)
  71                 assert pid == child
  72
  73                 output.seek(0)
  74                 results = output.read()
  75                 if status != 0:
  76                         results += _("Error from child process: exit code = %d") % status
  77         finally:
  78                 output.close()
  79
  80         return results
  81
  82 def _process_args(args, element):
  83         """Append each <arg> under <element> to args, performing $-expansion."""
  84         for child in element.childNodes:
  85                 if child.uri == namespaces.XMLNS_IFACE and child.name == 'arg':
  86                         args.append(Template(child.content).substitute(os.environ))
  87
  88 class Setup(object):
  89         """@since: 1.2"""
  90         stores = None
  91         selections = None
  92         _exec_bindings = None
  93
  94         def __init__(self, stores, selections):
  95                 """@param stores: where to find cached implementations
  96                 @type stores: L{zerostore.Stores}"""
  97                 self.stores = stores
  98                 self.selections = selections
  99
 100         def build_command(self, command_iface, command_name, user_command = None):
 101                 """Create a list of strings to be passed to exec to run the <command>s in the selections.
 102                 @param commands: the commands to be used (taken from selections is None)
 103                 @type commands: [L{model.Command}]
 104                 @return: the argument list
 105                 @rtype: [str]"""
 106
 107                 assert command_name
 108
 109                 prog_args = []
 110                 sels = self.selections.selections
 111
 112                 while command_name:
 113                         command_sel = sels[command_iface]
 114
 115                         if user_command is None:
 116                                 command = command_sel.get_command(command_name)
 117                         else:
 118                                 command = user_command
 119                                 user_command = None
 120
 121                         command_args = []
 122
 123                         # Add extra arguments for runner
 124                         runner = command.get_runner()
 125                         if runner:
 126                                 command_iface = runner.interface
 127                                 command_name = runner.command
 128                                 _process_args(command_args, runner.qdom)
 129                         else:
 130                                 command_iface = None
 131                                 command_name = None
 132
 133                         # Add main program path
 134                         command_path = command.path
 135                         if command_path is not None:
 136                                 if command_sel.id.startswith('package:'):
 137                                         prog_path = command_path
 138                                 else:
 139                                         if command_path.startswith('/'):
 140                                                 raise SafeException(_("Command path must be relative, but '%s' starts with '/'!") %
 141                                                                         command_path)
 142                                         prog_path = os.path.join(self._get_implementation_path(command_sel), command_path)
 143
 144                                 assert prog_path is not None
 145
 146                                 if not os.path.exists(prog_path):
 147                                         raise SafeException(_("File '%(program_path)s' does not exist.\n"
 148                                                         "(implementation '%(implementation_id)s' + program '%(main)s')") %
 149                                                         {'program_path': prog_path, 'implementation_id': command_sel.id,
 150                                                         'main': command_path})
 151
 152                                 command_args.append(prog_path)
 153
 154                         # Add extra arguments for program
 155                         _process_args(command_args, command.qdom)
 156
 157                         prog_args = command_args + prog_args
 158
 159                 # Each command is run by the next, but the last one is run by exec, and we
 160                 # need a path for that.
 161                 if command.path is None:
 162                         raise SafeException("Missing 'path' attribute on <command>")
 163
 164                 return prog_args
 165
 166         def _get_implementation_path(self, impl):
 167                 return impl.local_path or self.stores.lookup_any(impl.digests)
 168
 169         def prepare_env(self):
 170                 """Do all the environment bindings in the selections (setting os.environ)."""
 171                 self._exec_bindings = []
 172
 173                 def _do_bindings(impl, bindings, dep):
 174                         for b in bindings:
 175                                 self.do_binding(impl, b, dep)
 176
 177                 def _do_deps(deps):
 178                         for dep in deps:
 179                                 dep_impl = sels.get(dep.interface, None)
 180                                 if dep_impl is None:
 181                                         assert dep.importance != Dependency.Essential, dep
 182                                 elif not dep_impl.id.startswith('package:'):
 183                                         _do_bindings(dep_impl, dep.bindings, dep)
 184
 185                 sels = self.selections.selections
 186                 for selection in sels.values():
 187                         _do_bindings(selection, selection.bindings, None)
 188                         _do_deps(selection.dependencies)
 189
 190                         # Process commands' dependencies' bindings too
 191                         for command in selection.get_commands().values():
 192                                 _do_deps(command.requires)
 193
 194                 # Do these after <environment>s, because they may do $-expansion
 195                 for binding, dep in self._exec_bindings:
 196                         self.do_exec_binding(binding, dep)
 197                 self._exec_bindings = None
 198
 199         def do_binding(self, impl, binding, dep):
 200                 """Called by L{prepare_env} for each binding.
 201                 Sub-classes may wish to override this.
 202                 @param impl: the selected implementation
 203                 @type impl: L{selections.Selection}
 204                 @param binding: the binding to be processed
 205                 @type binding: L{model.Binding}
 206                 @param dep: the dependency containing the binding, or None for implementation bindings
 207                 @type dep: L{model.Dependency}
 208                 """
 209                 if isinstance(binding, EnvironmentBinding):
 210                         do_env_binding(binding, self._get_implementation_path(impl))
 211                 elif isinstance(binding, ExecutableBinding):
 212                         self._exec_bindings.append((binding, dep))
 213
 214         def do_exec_binding(self, binding, dep):
 215                 if dep is None:
 216                         raise SafeException("<%s> can only appear within a <requires>" % binding.qdom.name)
 217                 name = binding.name
 218                 if '/' in name or name.startswith('.') or "'" in name:
 219                         raise SafeException("Invalid <executable> name '%s'" % name)
 220                 exec_dir = basedir.save_cache_path(namespaces.config_site, namespaces.config_prog, 'executables', name)
 221                 exec_path = os.path.join(exec_dir, name)
 222                 if not os.path.exists(exec_path):
 223                         import tempfile
 224
 225                         # Create the runenv.py helper script under ~/.cache if missing
 226                         main_dir = basedir.save_cache_path(namespaces.config_site, namespaces.config_prog)
 227                         runenv = os.path.join(main_dir, 'runenv.py')
 228                         if not os.path.exists(runenv):
 229                                 tmp = tempfile.NamedTemporaryFile('w', dir = main_dir, delete = False)
 230                                 tmp.write("#!%s\nfrom zeroinstall.injector import _runenv; _runenv.main()\n" % sys.executable)
 231                                 tmp.close()
 232                                 os.chmod(tmp.name, 0555)
 233                                 os.rename(tmp.name, runenv)
 234
 235                         # Symlink ~/.cache/0install.net/injector/executables/$name/$name to runenv.py
 236                         os.symlink('../../runenv.py', exec_path)
 237                         os.chmod(exec_dir, 0o500)
 238
 239                 if binding.in_path:
 240                         path = os.environ["PATH"] = exec_dir + os.pathsep + os.environ["PATH"]
 241                         info("PATH=%s", path)
 242                 else:
 243                         os.environ[name] = exec_path
 244                         info("%s=%s", name, exec_path)
 245
 246                 import json
 247                 args = self.build_command(dep.interface, binding.command)
 248                 os.environ["0install-runenv-" + name] = json.dumps(args)
 249
 250 def execute_selections(selections, prog_args, dry_run = False, main = None, wrapper = None, stores = None):
 251         """Execute program. On success, doesn't return. On failure, raises an Exception.
 252         Returns normally only for a successful dry run.
 253         @param selections: the selected versions
 254         @type selections: L{selections.Selections}
 255         @param prog_args: arguments to pass to the program
 256         @type prog_args: [str]
 257         @param dry_run: if True, just print a message about what would have happened
 258         @type dry_run: bool
 259         @param main: the name of the binary to run, or None to use the default
 260         @type main: str
 261         @param wrapper: a command to use to actually run the binary, or None to run the binary directly
 262         @type wrapper: str
 263         @since: 0.27
 264         @precondition: All implementations are in the cache.
 265         """
 266         #assert stores is not None
 267         if stores is None:
 268                 from zeroinstall import zerostore
 269                 stores = zerostore.Stores()
 270
 271         setup = Setup(stores, selections)
 272
 273         commands = selections.commands
 274         if main is not None:
 275                 # Replace first command with user's input
 276                 if main.startswith('/'):
 277                         main = main[1:]                 # User specified a path relative to the package root
 278                 else:
 279                         old_path = commands[0].path
 280                         assert old_path, "Can't use a relative replacement main when there is no original one!"
 281                         main = os.path.join(os.path.dirname(old_path), main)    # User main is relative to command's name
 282                 # Copy all child nodes (e.g. <runner>) except for the arguments
 283                 user_command_element = qdom.Element(namespaces.XMLNS_IFACE, 'command', {'path': main})
 284                 if commands:
 285                         for child in commands[0].qdom.childNodes:
 286                                 if child.uri == namespaces.XMLNS_IFACE and child.name == 'arg':
 287                                         continue
 288                                 user_command_element.childNodes.append(child)
 289                 user_command = Command(user_command_element, None)
 290         else:
 291                 user_command = None
 292
 293         setup.prepare_env()
 294         prog_args = setup.build_command(selections.interface, selections.command, user_command) + prog_args
 295
 296         if wrapper:
 297                 prog_args = ['/bin/sh', '-c', wrapper + ' "$@"', '-'] + list(prog_args)
 298
 299         if dry_run:
 300                 print _("Would execute: %s") % ' '.join(prog_args)
 301         else:
 302                 info(_("Executing: %s"), prog_args)
 303                 sys.stdout.flush()
 304                 sys.stderr.flush()
 305                 try:
 306                         os.execv(prog_args[0], prog_args)
 307                 except OSError as ex:
 308                         raise SafeException(_("Failed to run '%(program_path)s': %(exception)s") % {'program_path': prog_args[0], 'exception': str(ex)})