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@@ -121,12 +121,6 @@ def fork():
# Parent and child process.
return pid, master_fd
def _writen(fd, data):
"""Write all the data to a descriptor."""
while data:
n = os.write(fd, data)
data = data[n:]
def _read(fd):
"""Default read function."""
return os.read(fd, 1024)
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@@ -136,9 +130,42 @@ def _copy(master_fd, master_read=_read, stdin_read=_read):
Copies
pty master -> standard output (master_read)
standard input -> pty master (stdin_read)"""
fds = [master_fd, STDIN_FILENO]
while fds:
rfds, _wfds, _xfds = select(fds, [], [])
if os.get_blocking(master_fd):
# If we write more than tty/ndisc is willing to buffer, we may block
# indefinitely. So we set master_fd to non-blocking temporarily during
# the copy operation.
os.set_blocking(master_fd, False)
try:
_copy(master_fd, master_read=master_read, stdin_read=stdin_read)
finally:
# restore blocking mode for backwards compatibility
os.set_blocking(master_fd, True)
return
high_waterlevel = 4096
stdin_avail = master_fd != STDIN_FILENO
stdout_avail = master_fd != STDOUT_FILENO
i_buf = b''
o_buf = b''
while 1:
rfds = []
wfds = []
if stdin_avail and len(i_buf) < high_waterlevel:
rfds.append(STDIN_FILENO)
if stdout_avail and len(o_buf) < high_waterlevel:
rfds.append(master_fd)
if stdout_avail and len(o_buf) > 0:
wfds.append(STDOUT_FILENO)
if len(i_buf) > 0:
wfds.append(master_fd)
rfds, wfds, _xfds = select(rfds, wfds, [])
if STDOUT_FILENO in wfds:
try:
n = os.write(STDOUT_FILENO, o_buf)
o_buf = o_buf[n:]
except OSError:
stdout_avail = False
if master_fd in rfds:
# Some OSes signal EOF by returning an empty byte string,
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@@ -150,15 +177,18 @@ def _copy(master_fd, master_read=_read, stdin_read=_read):
if not data: # Reached EOF.
return # Assume the child process has exited and is
# unreachable, so we clean up.
else:
os.write(STDOUT_FILENO, data)
o_buf += data
if master_fd in wfds:
n = os.write(master_fd, i_buf)
i_buf = i_buf[n:]
if STDIN_FILENO in rfds:
if stdin_avail and STDIN_FILENO in rfds:
data = stdin_read(STDIN_FILENO)
if not data:
fds.remove(STDIN_FILENO)
stdin_avail = False
else:
_writen(master_fd, data)
i_buf += data
def spawn(argv, master_read=_read, stdin_read=_read):
"""Create a spawned process."""
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