Provides the 'spawn()' function, a front-end to various platform-
specific functions for launching another program in a sub-process.
Also provides the 'find_executable()' to search the path for a given
# This module should be kept compatible with Python 2.1.
__revision__
= "$Id: spawn.py,v 1.19 2004/11/10 22:23:14 loewis Exp $"
from distutils
.errors
import *
from distutils
import log
"""Run another program, specified as a command list 'cmd', in a new
process. 'cmd' is just the argument list for the new process, ie.
cmd[0] is the program to run and cmd[1:] are the rest of its arguments.
There is no way to run a program with a name different from that of its
If 'search_path' is true (the default), the system's executable
search path will be used to find the program; otherwise, cmd[0]
must be the exact path to the executable. If 'dry_run' is true,
the command will not actually be run.
Raise DistutilsExecError if running the program fails in any way; just
_spawn_posix(cmd
, search_path
, dry_run
=dry_run
)
_spawn_nt(cmd
, search_path
, dry_run
=dry_run
)
_spawn_os2(cmd
, search_path
, dry_run
=dry_run
)
raise DistutilsPlatformError
, \
"don't know how to spawn programs on platform '%s'" % os
.name
def _nt_quote_args (args
):
"""Quote command-line arguments for DOS/Windows conventions: just
wraps every argument which contains blanks in double quotes, and
returns a new argument list.
# XXX this doesn't seem very robust to me -- but if the Windows guys
# say it'll work, I guess I'll have to accept it. (What if an arg
# contains quotes? What other magic characters, other than spaces,
# have to be escaped? Is there an escaping mechanism other than
for i
in range(len(args
)):
if string
.find(args
[i
], ' ') != -1:
args
[i
] = '"%s"' % args
[i
]
cmd
= _nt_quote_args(cmd
)
# either we find one or it stays the same
executable
= find_executable(executable
) or executable
log
.info(string
.join([executable
] + cmd
[1:], ' '))
# spawn for NT requires a full path to the .exe
rc
= os
.spawnv(os
.P_WAIT
, executable
, cmd
)
# this seems to happen when the command isn't found
raise DistutilsExecError
, \
"command '%s' failed: %s" % (cmd
[0], exc
[-1])
# and this reflects the command running but failing
raise DistutilsExecError
, \
"command '%s' failed with exit status %d" % (cmd
[0], rc
)
#cmd = _nt_quote_args(cmd)
# either we find one or it stays the same
executable
= find_executable(executable
) or executable
log
.info(string
.join([executable
] + cmd
[1:], ' '))
# spawnv for OS/2 EMX requires a full path to the .exe
rc
= os
.spawnv(os
.P_WAIT
, executable
, cmd
)
# this seems to happen when the command isn't found
raise DistutilsExecError
, \
"command '%s' failed: %s" % (cmd
[0], exc
[-1])
# and this reflects the command running but failing
print "command '%s' failed with exit status %d" % (cmd
[0], rc
)
raise DistutilsExecError
, \
"command '%s' failed with exit status %d" % (cmd
[0], rc
)
log
.info(string
.join(cmd
, ' '))
exec_fn
= search_path
and os
.execvp
or os
.execv
if pid
== 0: # in the child
#print "cmd[0] =", cmd[0]
sys
.stderr
.write("unable to execute %s: %s\n" %
sys
.stderr
.write("unable to execute %s for unknown reasons" % cmd
[0])
# Loop until the child either exits or is terminated by a signal
# (ie. keep waiting if it's merely stopped)
(pid
, status
) = os
.waitpid(pid
, 0)
if exc
.errno
== errno
.EINTR
:
raise DistutilsExecError
, \
"command '%s' failed: %s" % (cmd
[0], exc
[-1])
if os
.WIFSIGNALED(status
):
raise DistutilsExecError
, \
"command '%s' terminated by signal %d" % \
(cmd
[0], os
.WTERMSIG(status
))
elif os
.WIFEXITED(status
):
exit_status
= os
.WEXITSTATUS(status
)
return # hey, it succeeded!
raise DistutilsExecError
, \
"command '%s' failed with exit status %d" % \
elif os
.WIFSTOPPED(status
):
raise DistutilsExecError
, \
"unknown error executing '%s': termination status %d" % \
def find_executable(executable
, path
=None):
"""Try to find 'executable' in the directories listed in 'path' (a
string listing directories separated by 'os.pathsep'; defaults to
os.environ['PATH']). Returns the complete filename or None if not
path
= os
.environ
['PATH']
paths
= string
.split(path
, os
.pathsep
)
(base
, ext
) = os
.path
.splitext(executable
)
if (sys
.platform
== 'win32' or os
.name
== 'os2') and (ext
!= '.exe'):
executable
= executable
+ '.exe'
if not os
.path
.isfile(executable
):
f
= os
.path
.join(p
, executable
)
# the file exists, we have a shot at spawn working