Busybox file copy tool

devicecopy.py

#!/usr/bin/python
#
# Tool to copy files/directory trees to/from devices where the only opening
# is a telnet/serial shell and there is nothing other than a basic busybox on the device.
#


import sys, socket, tempfile, shutil, re, time
import telnetlib as T

# Busybox telnetd always expands tabs to spaces (this is hard-coded into telnetd.c)
XTABS_WORKAROUND = True

prompt = None

def expect(s, r, to=1000):
    buf = ""
    t0 = time.time()
    while (not r) or (not buf.endswith(r)):
        l = s.recv(4096)
        if len(l) == 0: break
        buf += l
        if time.time() - t0 > to: break
    return buf

# Expand / unexpand telnet IAC chars
def escape(s):
    return s.replace("\xff", "\xff\xff")
def unescape(s):
    return s.replace("\xff\xff", "\xff")

def do_cmd(s, cmd, stdin=False, stdout=False):
    cmd = escape(cmd).strip()
    if XTABS_WORKAROUND and stdout:
        cmd +=  ' | sed "s/#/##/g" | sed "s/\\t/#t/g"'
    cmd += '\r\n'
    print >>sys.stderr, ">>", cmd,
    s.send(cmd)
    if stdin:
        raise NotImplementedError()
    buf = unescape(expect(s, prompt))
    if buf.startswith(cmd): buf = buf[len(cmd):]
    if buf.endswith(prompt): buf = buf[:-len(prompt)]
    if XTABS_WORKAROUND and stdout:
        buf = buf.replace("#t","\t").replace("##","#")
    buf = buf.replace("\r\n", "\n")
    l = []
    return buf
    
def usage():
    print >>sys.stderr, "Usage: " + sys.argv[0] + " <dest> [getdir|get|putdir|put] <remotefile>"
    print >>sys.stderr, "Last-resort binary transfer when the only access is telnet or a"
    print >>sys.stderr, "serial console. When possible, use ssh/scp instead of this hack."
    print >>sys.stderr, ""
    print >>sys.stderr, "Local file is always stdin/stdout"
    print >>sys.stderr, "Examples:"
    print >>sys.stderr, "  " + sys.argv[0] + " 192.168.1.121 getdir / > rootfs.tar.gz"
    print >>sys.stderr, "  (Gets entire filesystem as tarball over telnet)"
    print >>sys.stderr, "  " + sys.argv[0] + " /dev/ttyUSB0 get /dev/mmcblk0p1 > part0.gz"
    print >>sys.stderr, "  (Gets block device as gzip over serial)"
    print >>sys.stderr, "  " + sys.argv[0] + " /dev/ttyUSB0 put /bin/ls < hacked_ls"
    print >>sys.stderr, "  (Replaces /bin/ls over serial)"

def do_connect(dest):
    global prompt
    hp = dest.split(":")
    port = 23
    if len(hp) > 1:
        port = int(hp[1])
    
    # Connect
    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    s.connect((hp[0], port))

    # Wait for prompt
    buf = expect(s, r"# ", .5)
    prompt = buf.split("\n")[-1]
    
    return s
    
def do_getdir(dest, remotefile):
    s = do_connect(dest)
    buf = do_cmd(s, 'tar -zc -C ' + remotefile + ' . 2>/dev/null', stdout=True)
    sys.stdout.write(buf)
    s.close() 
    
def do_get(dest, remotefile):
    s = do_connect(dest)
    buf = do_cmd(s, 'gzip 2>/dev/null < ' + remotefile, stdout=True)
    sys.stdout.write(buf)
    s.close() 
    
def do_put(dest, remotefile):
    s = do_connect(dest)
    buf = do_cmd(s, 'cat > ' + remotefile, stdin=True)
    sys.stdout.write(buf)
    s.close() 
    
def do_putdir(dest, remotefile):
    raise NotImplementedError("putdir command is not implemented")

if __name__ == '__main__':
    if len(sys.argv) <= 3:
        usage()
        sys.exit(1)
        
    dest = sys.argv[2]
    remotefile = sys.argv[3]
    if sys.argv[1] == "getdir":
        do_getdir(dest, remotefile)
    elif sys.argv[1] == "get":
        do_get(dest, remotefile)
    elif sys.argv[1] == "putdir":
        do_putdir(dest, remotefile)
    elif sys.argv[1] == "put":
        do_put(dest, remotefile)
    else:
        print >>sys.stderr, "Sub-command", sys.argv[1], "not recognized"
        usage()
        sys.exit(1)