blob: f02ccb1058999a84fed0cb59e3dc97e13b9a8e5b [file] [log] [blame] [edit]
#!/usr/bin/python
#
# gem5img.py
# Script for managing a gem5 disk image.
#
from optparse import OptionParser
import os
from os import environ as env
import string
from subprocess import CalledProcessError, Popen, PIPE, STDOUT
from sys import exit, argv
# Some constants.
MaxLBACylinders = 16383
MaxLBAHeads = 16
MaxLBASectors = 63
MaxLBABlocks = MaxLBACylinders * MaxLBAHeads * MaxLBASectors
BlockSize = 512
MB = 1024 * 1024
# Setup PATH to look in the sbins.
env['PATH'] += ':/sbin:/usr/sbin'
# Whether to print debug output.
debug = False
# Figure out cylinders, heads and sectors from a size in blocks.
def chsFromSize(sizeInBlocks):
if sizeInBlocks >= MaxLBABlocks:
sizeInMBs = (sizeInBlocks * BlockSize) / MB
print '%d MB is too big for LBA, truncating file.' % sizeInMBs
return (MaxLBACylinders, MaxLBAHeads, MaxLBASectors)
sectors = sizeInBlocks
if sizeInBlocks > 63:
sectors = 63
headSize = sizeInBlocks / sectors
heads = 16
if headSize < 16:
heads = sizeInBlocks
cylinders = sizeInBlocks / (sectors * heads)
return (cylinders, heads, sectors)
# Figure out if we should use sudo.
def needSudo():
if not hasattr(needSudo, 'notRoot'):
needSudo.notRoot = (os.geteuid() != 0)
if needSudo.notRoot:
print 'You are not root. Using sudo.'
return needSudo.notRoot
# Run an external command.
def runCommand(command, inputVal=''):
print "%>", ' '.join(command)
proc = Popen(command, stdin=PIPE)
proc.communicate(inputVal)
return proc.returncode
# Run an external command and capture its output. This is intended to be
# used with non-interactive commands where the output is for internal use.
def getOutput(command, inputVal=''):
global debug
if debug:
print "%>", ' '.join(command)
proc = Popen(command, stderr=STDOUT,
stdin=PIPE, stdout=PIPE)
(out, err) = proc.communicate(inputVal)
return (out, proc.returncode)
# Run a command as root, using sudo if necessary.
def runPriv(command, inputVal=''):
realCommand = command
if needSudo():
realCommand = [findProg('sudo')] + command
return runCommand(realCommand, inputVal)
def privOutput(command, inputVal=''):
realCommand = command
if needSudo():
realCommand = [findProg('sudo')] + command
return getOutput(realCommand, inputVal)
# Find the path to a program.
def findProg(program, cleanupDev=None):
(out, returncode) = getOutput(['which', program])
if returncode != 0:
if cleanupDev:
cleanupDev.destroy()
exit("Unable to find program %s, check your PATH variable." % program)
return string.strip(out)
class LoopbackDevice(object):
def __init__(self, devFile=None):
self.devFile = devFile
def __str__(self):
return str(self.devFile)
def setup(self, fileName, offset=False):
assert not self.devFile
(out, returncode) = privOutput([findProg('losetup'), '-f'])
if returncode != 0:
print out
return returncode
self.devFile = string.strip(out)
command = [findProg('losetup'), self.devFile, fileName]
if offset:
off = findPartOffset(self.devFile, fileName, 0)
command = command[:1] + \
["-o", "%d" % off] + \
command[1:]
return runPriv(command)
def destroy(self):
assert self.devFile
returncode = runPriv([findProg('losetup'), '-d', self.devFile])
self.devFile = None
return returncode
def findPartOffset(devFile, fileName, partition):
# Attach a loopback device to the file so we can use sfdisk on it.
dev = LoopbackDevice()
dev.setup(fileName)
# Dump the partition information.
command = [findProg('sfdisk'), '-d', dev.devFile]
(out, returncode) = privOutput(command)
if returncode != 0:
print out
exit(returncode)
lines = out.splitlines()
# Make sure the first few lines of the output look like what we expect.
assert(lines[0][0] == '#')
assert(lines[1] == 'unit: sectors')
assert(lines[2] == '')
# This line has information about the first partition.
chunks = lines[3].split()
# The fourth chunk is the offset of the partition in sectors followed by
# a comma. We drop the comma and convert that to an integer.
sectors = string.atoi(chunks[3][:-1])
# Free the loopback device and return an answer.
dev.destroy()
return sectors * BlockSize
def mountPointToDev(mountPoint):
(mountTable, returncode) = getOutput([findProg('mount')])
if returncode != 0:
print mountTable
exit(returncode)
mountTable = mountTable.splitlines()
for line in mountTable:
chunks = line.split()
if os.path.samefile(chunks[2], mountPoint):
return LoopbackDevice(chunks[0])
return None
# Commands for the gem5img.py script
commands = {}
commandOrder = []
class Command(object):
def addOption(self, *args, **kargs):
self.parser.add_option(*args, **kargs)
def __init__(self, name, description, posArgs):
self.name = name
self.description = description
self.func = None
self.posArgs = posArgs
commands[self.name] = self
commandOrder.append(self.name)
usage = 'usage: %prog [options]'
posUsage = ''
for posArg in posArgs:
(argName, argDesc) = posArg
usage += ' %s' % argName
posUsage += '\n %s: %s' % posArg
usage += posUsage
self.parser = OptionParser(usage=usage, description=description)
self.addOption('-d', '--debug', dest='debug', action='store_true',
help='Verbose output.')
def parseArgs(self, argv):
(self.options, self.args) = self.parser.parse_args(argv[2:])
if len(self.args) != len(self.posArgs):
self.parser.error('Incorrect number of arguments')
global debug
if self.options.debug:
debug = True
def runCom(self):
if not self.func:
exit('Unimplemented command %s!' % self.name)
self.func(self.options, self.args)
# A command which prepares an image with an partition table and an empty file
# system.
initCom = Command('init', 'Create an image with an empty file system.',
[('file', 'Name of the image file.'),
('mb', 'Size of the file in MB.')])
initCom.addOption('-t', '--type', dest='fstype', action='store',
default='ext2',
help='Type of file system to use. Appended to mkfs.')
# A command to mount the first partition in the image.
mountCom = Command('mount', 'Mount the first partition in the disk image.',
[('file', 'Name of the image file.'),
('mount point', 'Where to mount the image.')])
def mountComFunc(options, args):
(path, mountPoint) = args
if not os.path.isdir(mountPoint):
print "Mount point %s is not a directory." % mountPoint
dev = LoopbackDevice()
if dev.setup(path, offset=True) != 0:
exit(1)
if runPriv([findProg('mount'), str(dev), mountPoint]) != 0:
dev.destroy()
exit(1)
mountCom.func = mountComFunc
# A command to unmount the first partition in the image.
umountCom = Command('umount', 'Unmount the first partition in the disk image.',
[('mount point', 'What mount point to unmount.')])
def umountComFunc(options, args):
(mountPoint,) = args
if not os.path.isdir(mountPoint):
print "Mount point %s is not a directory." % mountPoint
exit(1)
dev = mountPointToDev(mountPoint)
if not dev:
print "Unable to find mount information for %s." % mountPoint
# Unmount the loopback device.
if runPriv([findProg('umount'), mountPoint]) != 0:
exit(1)
# Destroy the loopback device.
dev.destroy()
umountCom.func = umountComFunc
# A command to create an empty file to hold the image.
newCom = Command('new', 'File creation part of "init".',
[('file', 'Name of the image file.'),
('mb', 'Size of the file in MB.')])
def newImage(file, mb):
(cylinders, heads, sectors) = chsFromSize((mb * MB) / BlockSize)
size = cylinders * heads * sectors * BlockSize
# We lseek to the end of the file and only write one byte there. This
# leaves a "hole" which many file systems are smart enough not to actually
# store to disk and which is defined to read as zero.
fd = os.open(file, os.O_WRONLY | os.O_CREAT)
os.lseek(fd, size - 1, os.SEEK_SET)
os.write(fd, '\0')
def newComFunc(options, args):
(file, mb) = args
mb = string.atoi(mb)
newImage(file, mb)
newCom.func = newComFunc
# A command to partition the image file like a raw disk device.
partitionCom = Command('partition', 'Partition part of "init".',
[('file', 'Name of the image file.')])
def partition(dev, cylinders, heads, sectors):
# Use fdisk to partition the device
comStr = '0,\n;\n;\n;\n'
return runPriv([findProg('sfdisk'), '--no-reread', '-D', \
'-C', "%d" % cylinders, \
'-H', "%d" % heads, \
'-S', "%d" % sectors, \
str(dev)], inputVal=comStr)
def partitionComFunc(options, args):
(path,) = args
dev = LoopbackDevice()
if dev.setup(path) != 0:
exit(1)
# Figure out the dimensions of the file.
size = os.path.getsize(path)
if partition(dev, *chsFromSize(size / BlockSize)) != 0:
dev.destroy()
exit(1)
dev.destroy()
partitionCom.func = partitionComFunc
# A command to format the first partition in the image.
formatCom = Command('format', 'Formatting part of "init".',
[('file', 'Name of the image file.')])
formatCom.addOption('-t', '--type', dest='fstype', action='store',
default='ext2',
help='Type of file system to use. Appended to mkfs.')
def formatImage(dev, fsType):
return runPriv([findProg('mkfs.%s' % fsType, dev), str(dev)])
def formatComFunc(options, args):
(path,) = args
dev = LoopbackDevice()
if dev.setup(path, offset=True) != 0:
exit(1)
# Format the device.
if formatImage(dev, options.fstype) != 0:
dev.destroy()
exit(1)
dev.destroy()
formatCom.func = formatComFunc
def initComFunc(options, args):
(path, mb) = args
mb = string.atoi(mb)
newImage(path, mb)
dev = LoopbackDevice()
if dev.setup(path) != 0:
exit(1)
size = os.path.getsize(path)
if partition(dev, *chsFromSize((mb * MB) / BlockSize)) != 0:
dev.destroy()
exit(1)
dev.destroy()
if dev.setup(path, offset=True) != 0:
exit(1)
if formatImage(dev, options.fstype) != 0:
dev.destroy()
exit(1)
dev.destroy()
initCom.func = initComFunc
# Figure out what command was requested and execute it.
if len(argv) < 2 or argv[1] not in commands:
print 'Usage: %s [command] <command arguments>'
print 'where [command] is one of '
for name in commandOrder:
command = commands[name]
print ' %s: %s' % (command.name, command.description)
print 'Watch for orphaned loopback devices and delete them with'
print 'losetup -d. Mounted images will belong to root, so you may need'
print 'to use sudo to modify their contents.'
exit(1)
command = commands[argv[1]]
command.parseArgs(argv)
command.runCom()