def test_unsetCloseOnExec(self):
"""
A file descriptor passed to L{fdesc._unsetCloseOnExec} is inherited by
a new process image created with one of the exec family of functions.
"""
with open(self.mktemp(), 'wb') as fObj:
fdesc._setCloseOnExec(fObj.fileno())
fdesc._unsetCloseOnExec(fObj.fileno())
status = self._execWithFileDescriptor(fObj)
self.assertTrue(os.WIFEXITED(status))
self.assertEqual(os.WEXITSTATUS(status), 20)
def test_unsetCloseOnExec(self):
"""
A file descriptor passed to L{fdesc._unsetCloseOnExec} is inherited by
a new process image created with one of the exec family of functions.
"""
with open(self.mktemp(), 'wb') as fObj:
fdesc._setCloseOnExec(fObj.fileno())
fdesc._unsetCloseOnExec(fObj.fileno())
status = self._execWithFileDescriptor(fObj)
self.assertTrue(os.WIFEXITED(status))
self.assertEqual(os.WEXITSTATUS(status), 20)
def _setupChild(self, fdmap):
"""
fdmap[childFD] = parentFD
The child wants to end up with 'childFD' attached to what used to be
the parent's parentFD. As an example, a bash command run like
'command 2>&1' would correspond to an fdmap of {0:0, 1:1, 2:1}.
'command >foo.txt' would be {0:0, 1:os.open('foo.txt'), 2:2}.
This is accomplished in two steps::
1. close all file descriptors that aren't values of fdmap. This
means 0 .. maxfds (or just the open fds within that range, if
the platform supports '/proc/<pid>/fd').
2. for each childFD::
- if fdmap[childFD] == childFD, the descriptor is already in
place. Make sure the CLOEXEC flag is not set, then delete
the entry from fdmap.
- if childFD is in fdmap.values(), then the target descriptor
is busy. Use os.dup() to move it elsewhere, update all
fdmap[childFD] items that point to it, then close the
original. Then fall through to the next case.
- now fdmap[childFD] is not in fdmap.values(), and is free.
Use os.dup2() to move it to the right place, then close the
original.
"""
debug = self.debug_child
if debug:
errfd = sys.stderr
errfd.write("starting _setupChild\n")
destList = fdmap.values()
for fd in _listOpenFDs():
if fd in destList:
continue
if debug and fd == errfd.fileno():
continue
try:
os.close(fd)
except BaseException:
pass
# at this point, the only fds still open are the ones that need to
# be moved to their appropriate positions in the child (the targets
# of fdmap, i.e. fdmap.values() )
if debug:
print("fdmap", fdmap, file=errfd)
for child in sorted(fdmap.keys()):
target = fdmap[child]
if target == child:
# fd is already in place
if debug:
print("%d already in place" % target, file=errfd)
fdesc._unsetCloseOnExec(child)
else:
if child in fdmap.values():
# we can't replace child-fd yet, as some other mapping
# still needs the fd it wants to target. We must preserve
# that old fd by duping it to a new home.
newtarget = os.dup(child) # give it a safe home
if debug:
print("os.dup(%d) -> %d" % (child, newtarget),
file=errfd)
os.close(child) # close the original
for c, p in list(fdmap.items()):
if p == child:
fdmap[c] = newtarget # update all pointers
# now it should be available
if debug:
print("os.dup2(%d,%d)" % (target, child), file=errfd)
os.dup2(target, child)
# At this point, the child has everything it needs. We want to close
# everything that isn't going to be used by the child, i.e.
# everything not in fdmap.keys(). The only remaining fds open are
# those in fdmap.values().
# Any given fd may appear in fdmap.values() multiple times, so we
# need to remove duplicates first.
old = []
for fd in fdmap.values():
if fd not in old:
if fd not in fdmap.keys():
old.append(fd)
if debug:
print("old", old, file=errfd)
for fd in old:
os.close(fd)
self._resetSignalDisposition()
def _setupChild(self, fdmap):
"""
fdmap[childFD] = parentFD
The child wants to end up with 'childFD' attached to what used to be
the parent's parentFD. As an example, a bash command run like
'command 2>&1' would correspond to an fdmap of {0:0, 1:1, 2:1}.
'command >foo.txt' would be {0:0, 1:os.open('foo.txt'), 2:2}.
This is accomplished in two steps::
1. close all file descriptors that aren't values of fdmap. This
means 0 .. maxfds (or just the open fds within that range, if
the platform supports '/proc/<pid>/fd').
2. for each childFD::
- if fdmap[childFD] == childFD, the descriptor is already in
place. Make sure the CLOEXEC flag is not set, then delete
the entry from fdmap.
- if childFD is in fdmap.values(), then the target descriptor
is busy. Use os.dup() to move it elsewhere, update all
fdmap[childFD] items that point to it, then close the
original. Then fall through to the next case.
- now fdmap[childFD] is not in fdmap.values(), and is free.
Use os.dup2() to move it to the right place, then close the
original.
"""
debug = self.debug_child
if debug:
errfd = sys.stderr
errfd.write("starting _setupChild\n")
destList = fdmap.values()
for fd in _listOpenFDs():
if fd in destList:
continue
if debug and fd == errfd.fileno():
continue
try:
os.close(fd)
except:
pass
# at this point, the only fds still open are the ones that need to
# be moved to their appropriate positions in the child (the targets
# of fdmap, i.e. fdmap.values() )
if debug: print >>errfd, "fdmap", fdmap
childlist = fdmap.keys()
childlist.sort()
for child in childlist:
target = fdmap[child]
if target == child:
# fd is already in place
if debug: print >>errfd, "%d already in place" % target
fdesc._unsetCloseOnExec(child)
else:
if child in fdmap.values():
# we can't replace child-fd yet, as some other mapping
# still needs the fd it wants to target. We must preserve
# that old fd by duping it to a new home.
newtarget = os.dup(child) # give it a safe home
if debug: print >>errfd, "os.dup(%d) -> %d" % (child,
newtarget)
os.close(child) # close the original
for c, p in fdmap.items():
if p == child:
fdmap[c] = newtarget # update all pointers
# now it should be available
if debug: print >>errfd, "os.dup2(%d,%d)" % (target, child)
os.dup2(target, child)
# At this point, the child has everything it needs. We want to close
# everything that isn't going to be used by the child, i.e.
# everything not in fdmap.keys(). The only remaining fds open are
# those in fdmap.values().
# Any given fd may appear in fdmap.values() multiple times, so we
# need to remove duplicates first.
old = []
for fd in fdmap.values():
if not fd in old:
if not fd in fdmap.keys():
old.append(fd)
if debug: print >>errfd, "old", old
for fd in old:
os.close(fd)
self._resetSignalDisposition()
def __iter__(self):
for description, fileno in self._descriptionsAndFilenos:
fdesc._unsetCloseOnExec(fileno)
yield description, fileno
