#!/usr/bin/python

# Copyright (c) 2003 Intel Corporation
# All rights reserved.
#
# Copyright (c) 2004-2006 The Trustees of Princeton University
# All rights reserved.
# expected /proc/partitions format

import os, sys, shutil
import popen2
import socket
import fcntl
import string
import exceptions

from Exceptions import *


### handling breakpoints in the startup process
import select, sys, string

### global debug settings
# NOTE. when BREAKPOINT_MODE turns out enabled,
# you have to attend the boot phase, that would hang otherwise 

# enabling this will cause the node to ask for breakpoint-mode at startup
# production code should read False/False
PROMPT_MODE=False
# default for when prompt is turned off, or it's on but the timeout triggers
BREAKPOINT_MODE=False
VERBOSE_MODE=False
VERBOSE_MODE=True
# in seconds : if no input, proceed
PROMPT_TIMEOUT=5

def prompt_for_breakpoint_mode ():

    global BREAKPOINT_MODE
    if PROMPT_MODE:
        default_answer=BREAKPOINT_MODE
        answer=''
        if BREAKPOINT_MODE:
            display="[y]/n"
        else:
            display="y/[n]"
        sys.stdout.write ("Want to run in breakpoint mode ? %s "%display)
        sys.stdout.flush()
        r,w,e = select.select ([sys.stdin],[],[],PROMPT_TIMEOUT)
        if r:
            answer = string.strip(sys.stdin.readline())
        else:
            sys.stdout.write("\nTimed-out (%d s)"%PROMPT_TIMEOUT)
        if answer:
            BREAKPOINT_MODE = ( answer == "y" or answer == "Y")
        else:
            BREAKPOINT_MODE = default_answer
    label="Off"
    if BREAKPOINT_MODE:
        label="On"
    sys.stdout.write("\nCurrent BREAKPOINT_MODE is %s\n"%label)

def breakpoint (message, cmd = None):

    if BREAKPOINT_MODE:

        if cmd is None:
            cmd="/bin/sh"
            message=message+" -- Entering bash - type ^D to proceed"

        print message
        os.system(cmd)


########################################
def makedirs( path ):
    """
    from python docs for os.makedirs:
    Throws an error exception if the leaf directory
    already exists or cannot be created.

    That is real useful. Instead, we'll create the directory, then use a
    separate function to test for its existance.

    Return 1 if the directory exists and/or has been created, a BootManagerException
    otherwise. Does not test the writability of said directory.
    """
    try:
        os.makedirs( path )
    except OSError:
        pass
    try:
        os.listdir( path )
    except OSError:
        raise BootManagerException, "Unable to create directory tree: %s" % path
    
    return 1



def removedir( path ):
    """
    remove a directory tree, return 1 if successful, a BootManagerException
    if failure.
    """
    try:
        os.listdir( path )
    except OSError:
        return 1

    try:
        shutil.rmtree( path )
    except OSError, desc:
        raise BootManagerException, "Unable to remove directory tree: %s" % path
    
    return 1



def sysexec( cmd, log= None ):
    """
    execute a system command, output the results to the logger
    if log <> None

    return 1 if command completed (return code of non-zero),
    0 if failed. A BootManagerException is raised if the command
    was unable to execute or was interrupted by the user with Ctrl+C
    """
    if VERBOSE_MODE:
        print ("sysexec >>> %s" % cmd)
    prog= popen2.Popen4( cmd, 0 )
    if prog is None:
        raise BootManagerException, \
              "Unable to create instance of popen2.Popen4 " \
              "for command: %s" % cmd

    if log is not None:
        try:
            for line in prog.fromchild:
                log.write( line )
        except KeyboardInterrupt:
            raise BootManagerException, "Interrupted by user"

    returncode= prog.wait()
    if returncode != 0:
        raise BootManagerException, "Running %s failed (rc=%d)" % (cmd,returncode)

    prog= None
    return 1


def sysexec_chroot( path, cmd, log= None ):
    """
    same as sysexec, but inside a chroot
    """
    preload = ""
    release = os.uname()[2]
    # 2.6.12 kernels need this
    if release[:5] == "2.6.1":
        library = "%s/lib/libc-opendir-hack.so" % path
        if not os.path.exists(library):
            shutil.copy("./libc-opendir-hack.so", library)
        preload = "/bin/env LD_PRELOAD=/lib/libc-opendir-hack.so"
    sysexec("chroot %s %s %s" % (path, preload, cmd), log)


def sysexec_chroot_noerr( path, cmd, log= None ):
    """
    same as sysexec_chroot, but capture boot manager exceptions
    """
    try:
        rc= 0
        rc= syexec_chroot( cmd, log )
    except BootManagerException, e:
        pass

    return rc


def sysexec_noerr( cmd, log= None ):
    """
    same as sysexec, but capture boot manager exceptions
    """
    try:
        rc= 0
        rc= sysexec( cmd, log )
    except BootManagerException, e:
        pass

    return rc



def chdir( dir ):
    """
    change to a directory, return 1 if successful, a BootManagerException if failure
    """
    try:
        os.chdir( dir )
    except OSError:
        raise BootManagerException, "Unable to change to directory: %s" % dir

    return 1



def removefile( filepath ):
    """
    removes a file, return 1 if successful, 0 if failure
    """
    try:
        os.remove( filepath )
    except OSError:
        raise BootManagerException, "Unable to remove file: %s" % filepath

    return 1



# from: http://forums.devshed.com/archive/t-51149/
#              Ethernet-card-address-Through-Python-or-C

def hexy(n):
    return "%02x" % (ord(n))

def get_mac_from_interface(ifname):
    """
    given a device name, like eth0, return its mac_address.
    return None if the device doesn't exist.
    """
    
    SIOCGIFHWADDR = 0x8927 # magic number

    s=socket.socket(socket.AF_INET,socket.SOCK_STREAM)
    ifname = string.strip(ifname)
    ifr = ifname + '\0'*(32-len(ifname))

    try:
        r= fcntl.ioctl(s.fileno(),SIOCGIFHWADDR,ifr)
        addr = map(hexy,r[18:24])
        ret = (':'.join(map(str, addr)))
    except IOError, e:
        ret = None
        
    return ret