wxPython/distutils/spawn.py

   1 """distutils.spawn
   2
   3 Provides the 'spawn()' function, a front-end to various platform-
   4 specific functions for launching another program in a sub-process.
   5 Also provides the 'find_executable()' to search the path for a given
   6 executable name.
   7 """
   8
   9 # This module should be kept compatible with Python 1.5.2.
  10
  11 __revision__ = "$Id$"
  12
  13 import sys, os, string
  14 from distutils.errors import *
  15 from distutils import log
  16
  17 def spawn (cmd,
  18            search_path=1,
  19            verbose=0,
  20            dry_run=0):
  21
  22     """Run another program, specified as a command list 'cmd', in a new
  23     process.  'cmd' is just the argument list for the new process, ie.
  24     cmd[0] is the program to run and cmd[1:] are the rest of its arguments.
  25     There is no way to run a program with a name different from that of its
  26     executable.
  27
  28     If 'search_path' is true (the default), the system's executable
  29     search path will be used to find the program; otherwise, cmd[0]
  30     must be the exact path to the executable.  If 'dry_run' is true,
  31     the command will not actually be run.
  32
  33     Raise DistutilsExecError if running the program fails in any way; just
  34     return on success.
  35     """
  36     if os.name == 'posix':
  37         _spawn_posix(cmd, search_path, dry_run=dry_run)
  38     elif os.name == 'nt':
  39         _spawn_nt(cmd, search_path, dry_run=dry_run)
  40     elif os.name == 'os2':
  41         _spawn_os2(cmd, search_path, dry_run=dry_run)
  42     else:
  43         raise DistutilsPlatformError, \
  44               "don't know how to spawn programs on platform '%s'" % os.name
  45
  46 # spawn ()
  47
  48
  49 def _nt_quote_args (args):
  50     """Quote command-line arguments for DOS/Windows conventions: just
  51     wraps every argument which contains blanks in double quotes, and
  52     returns a new argument list.
  53     """
  54
  55     # XXX this doesn't seem very robust to me -- but if the Windows guys
  56     # say it'll work, I guess I'll have to accept it.  (What if an arg
  57     # contains quotes?  What other magic characters, other than spaces,
  58     # have to be escaped?  Is there an escaping mechanism other than
  59     # quoting?)
  60
  61     for i in range(len(args)):
  62         if string.find(args[i], ' ') != -1:
  63             args[i] = '"%s"' % args[i]
  64     return args
  65
  66 def _spawn_nt (cmd,
  67                search_path=1,
  68                verbose=0,
  69                dry_run=0):
  70
  71     executable = cmd[0]
  72     cmd = _nt_quote_args(cmd)
  73     if search_path:
  74         # either we find one or it stays the same
  75         executable = find_executable(executable) or executable
  76     log.info(string.join([executable] + cmd[1:], ' '))
  77     if not dry_run:
  78         # spawn for NT requires a full path to the .exe
  79         try:
  80             rc = os.spawnv(os.P_WAIT, executable, cmd)
  81         except OSError, exc:
  82             # this seems to happen when the command isn't found
  83             raise DistutilsExecError, \
  84                   "command '%s' failed: %s" % (cmd[0], exc[-1])
  85         if rc != 0:
  86             # and this reflects the command running but failing
  87             raise DistutilsExecError, \
  88                   "command '%s' failed with exit status %d" % (cmd[0], rc)
  89
  90
  91 def _spawn_os2 (cmd,
  92                 search_path=1,
  93                 verbose=0,
  94                 dry_run=0):
  95
  96     executable = cmd[0]
  97     #cmd = _nt_quote_args(cmd)
  98     if search_path:
  99         # either we find one or it stays the same
 100         executable = find_executable(executable) or executable
 101     log.info(string.join([executable] + cmd[1:], ' '))
 102     if not dry_run:
 103         # spawnv for OS/2 EMX requires a full path to the .exe
 104         try:
 105             rc = os.spawnv(os.P_WAIT, executable, cmd)
 106         except OSError, exc:
 107             # this seems to happen when the command isn't found
 108             raise DistutilsExecError, \
 109                   "command '%s' failed: %s" % (cmd[0], exc[-1])
 110         if rc != 0:
 111             # and this reflects the command running but failing
 112             print "command '%s' failed with exit status %d" % (cmd[0], rc)
 113             raise DistutilsExecError, \
 114                   "command '%s' failed with exit status %d" % (cmd[0], rc)
 115
 116
 117 def _spawn_posix (cmd,
 118                   search_path=1,
 119                   verbose=0,
 120                   dry_run=0):
 121
 122     log.info(string.join(cmd, ' '))
 123     if dry_run:
 124         return
 125     exec_fn = search_path and os.execvp or os.execv
 126
 127     pid = os.fork()
 128
 129     if pid == 0:                        # in the child
 130         try:
 131             #print "cmd[0] =", cmd[0]
 132             #print "cmd =", cmd
 133             exec_fn(cmd[0], cmd)
 134         except OSError, e:
 135             sys.stderr.write("unable to execute %s: %s\n" %
 136                              (cmd[0], e.strerror))
 137             os._exit(1)
 138
 139         sys.stderr.write("unable to execute %s for unknown reasons" % cmd[0])
 140         os._exit(1)
 141
 142
 143     else:                               # in the parent
 144         # Loop until the child either exits or is terminated by a signal
 145         # (ie. keep waiting if it's merely stopped)
 146         while 1:
 147             (pid, status) = os.waitpid(pid, 0)
 148             if os.WIFSIGNALED(status):
 149                 raise DistutilsExecError, \
 150                       "command '%s' terminated by signal %d" % \
 151                       (cmd[0], os.WTERMSIG(status))
 152
 153             elif os.WIFEXITED(status):
 154                 exit_status = os.WEXITSTATUS(status)
 155                 if exit_status == 0:
 156                     return              # hey, it succeeded!
 157                 else:
 158                     raise DistutilsExecError, \
 159                           "command '%s' failed with exit status %d" % \
 160                           (cmd[0], exit_status)
 161
 162             elif os.WIFSTOPPED(status):
 163                 continue
 164
 165             else:
 166                 raise DistutilsExecError, \
 167                       "unknown error executing '%s': termination status %d" % \
 168                       (cmd[0], status)
 169 # _spawn_posix ()
 170
 171
 172 def find_executable(executable, path=None):
 173     """Try to find 'executable' in the directories listed in 'path' (a
 174     string listing directories separated by 'os.pathsep'; defaults to
 175     os.environ['PATH']).  Returns the complete filename or None if not
 176     found.
 177     """
 178     if path is None:
 179         path = os.environ['PATH']
 180     paths = string.split(path, os.pathsep)
 181     (base, ext) = os.path.splitext(executable)
 182     if (sys.platform == 'win32' or os.name == 'os2') and (ext != '.exe'):
 183         executable = executable + '.exe'
 184     if not os.path.isfile(executable):
 185         for p in paths:
 186             f = os.path.join(p, executable)
 187             if os.path.isfile(f):
 188                 # the file exists, we have a shot at spawn working
 189                 return f
 190         return None
 191     else:
 192         return executable
 193
 194 # find_executable()